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Background: The efficacy of a neuromuscular training (NMT) program to ameliorate known hip biomechanical risk factors for athletes with anterior cruciate ligament reconstruction (ACLR) is currently unknown. Purpose/Hypothesis: The purpose was to quantify the effects of an NMT program on hip biomechanics among athletes with ACLR and to compare posttraining hip biomechanics with a control group. The hypotheses were that known hip biomechanical risk factors of anterior cruciate ligament (ACL) injury would be significantly reduced among athletes with ACLR after the NMT program and that posttraining hip biomechanics between the ACLR and control cohorts would not differ. Study Design: Controlled laboratory study. Methods: Twenty-eight athletes (n = 18, ACLR; n = 10, uninjured) completed a 12-session NMT program. Biomechanical evaluation of a jump-landing task was done before and after completion of the program. Repeated measures analysis of variance was performed to understand the effect of NMT within the ACLR cohort. Two-way analysis of variance was used to compare both groups. Post hoc testing was done for significant interactions. Hip biomechanical variables at initial contact are reported. Results: The athletes with ACLR who completed the NMT program had a significant session × limb interaction (P = .01) for hip external rotation moment and a significant main effect of session for hip flexion angle (P = .049) and moment (P < .001). There was a significant change for the involved (P = .04; 528% increase) and uninvolved (P = .04; 57% decrease) limbs from pre- to posttraining for hip rotation moment. The ACLR cohort had an increase in hip flexion angle (14% change) and a decrease in hip flexion moment (65% change) from pre- to posttraining. Posttraining comparison for these same hip biomechanical variables of interest revealed no significant interactions (P > .05) between the ACLR and control cohorts. There was a significant main effect of group (P = .02) for hip flexion angle, as the ACLR cohort demonstrated greater hip flexion angle than that of the control group. Conclusion: For athletes with ACLR, hip biomechanical measures of ACL injury risk show significant improvements after completion of an NMT program. Clinical Relevance: Athletes with ACLR who are participating in an NMT program may ameliorate known hip biomechanical risk factors for an ACL injury. [ABSTRACT FROM AUTHOR]

Background: Anatomic reconstruction techniques are increasingly used to address cases of acromioclavicular (AC) joint chronic instability. These usually involve an additional surgical site for autograft harvesting or an allograft. Purpose: To describe a triple-bundle (TB) anatomic reconstruction using on-site autografts, the semiconjoint tendon (SCT) and the coracoacromial ligament (CAL), and compare its primary stability to the native AC joint ligamentous complex and to a modified Weaver-Dunn (WD) reconstruction. Study Design: Controlled laboratory study. Methods: Intact AC joints of 12 paired cadaveric shoulders were tested for anterior, posterior, and superior translations under cyclic loading with a servo-hydraulic testing system. One shoulder from each pair was randomly assigned to the TB group, where 2 SCT strips were used to reconstruct the coracoclavicular ligaments while the distal end of the CAL was transferred to the distal extremity of the clavicle to reconstruct the AC ligaments; the other shoulder received a modified WD reconstruction. After reconstruction, the same translational testing was performed, with an additional load-to-failure test in the superior direction. Results: In both the TB and the WD groups, no significant differences were found before and after reconstruction in terms of joint displacements after cyclic loading, in all 3 directions. Compared with the WD reconstruction, the TB repair resulted in significantly lower displacements in both the anterior (ie, 2.59 ± 1.08 mm, P = .011) and posterior (ie, 10.17 ± 6.24 mm, P = .014) directions, but not in the superior direction. No significant differences were observed between the 2 reconstructions during the load-to-failure testing, except for the displacement to failure, which was significantly smaller (ie, 5.34 ± 2.97 mm) in the WD group (P = .037). Conclusion: Anterior, posterior, and superior displacements after an anatomic reconstruction of the AC joint complex using the SCT and CAL as graft material were similar to those of native AC joints and significantly smaller in the axial plane than those of AC joints after a WD repair. Clinical Relevance: An anatomic reconstruction is achievable using the CAL and the SCT as on-site graft materials, providing satisfactory initial stability and thereby allowing earlier mobilization. [ABSTRACT FROM AUTHOR]

Background: The optimal treatment for a medium- or large-sized cartilage lesion is still controversial. Since an ultrapurified alginate (UPAL) gel enhances cartilage repair in animal models, this material is expected to improve the efficacy of the current treatment strategies for cartilage lesions. Hypothesis: The bone marrow stimulation technique (BMST) augmented by UPAL gel can induce hyaline-like cartilage repair. Study Design: Controlled laboratory study. Methods: Two cylindrical osteochondral defects were created in the patellar groove of 27 beagle dogs. A total of 108 defects were divided into 3 groups: defects without intervention (control group), defects with the BMST (microfracture group), and defects with the BMST augmented by implantation of UPAL gel (combined group). At 27 weeks postoperatively, macroscopic and histological evaluations, micro–computed tomography assessment, and mechanical testing were performed for each reparative tissue. Results: The defects in the combined group were almost fully covered with translucent reparative tissues, which consisted of hyaline-like cartilage with well-organized collagen structures. The macroscopic score was significantly better in the combined group than in the control group (P < .05). The histological scores in the combined group were significantly better than those in the control group (P < .01) and microfracture group (P < .05). Although the repaired subchondral bone volumes were not influenced by UPAL gel augmentation, the mechanical properties of the combined group were significantly better than those of the microfracture group (P < .05). Conclusion: The BMST augmented by UPAL gel elicited hyaline-like cartilage repair that had characteristics of rich glycosaminoglycan and matrix immunostained by type II collagen antibody in a canine osteochondral defect model. The present results suggest that the current technique has the potential to be one of the autologous matrix-induced chondrogenesis techniques of the future and to expand the operative indications for the BMST without loss of its technical simplicity. Clinical Relevance: The data support the clinical reality of 1-step minimally invasive cartilage-reparative medicine with UPAL gel without harvesting donor cells. [ABSTRACT FROM AUTHOR]

Background: Measuring the size of the anterior cruciate ligament (ACL) tibial footprint on magnetic resonance image (MRI) is common for preoperative planning of ACL reconstruction. However, the accuracy of such measurement has not been well documented. Purpose: To investigate whether the actual size of the ACL tibial footprint could be predicted by its measurement on MRI and to develop equations to improve the accuracy of predicting the actual size based on MRI measurement. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A total of 164 patients with normal visualized ACL in gross evaluation and MRI were included (mean ± SD age, 67.3 ± 8.3 years). Cases with ACL tear, severe mucoid degeneration, osteophyte around the ACL tibial insertion, or intervals >12 months between MRI and actual measurement were excluded. The ACL tibial footprint was carefully dissected and measured during total knee arthroplasty. The length of the ACL tibial footprint on MRI was measured on a sagittal image, while the width was measured on an oblique coronal image. For the ACL tibial footprint, the association between measurement on MRI and actual measurement of length and width was analyzed via univariable and multivariable regression analyses. Reliability of measurements on MRI was also evaluated. Results: The length and width of the ACL tibial footprint as measured on MRI showed strong correlation with the actual length and width (coefficients: ρ = 0.904 and ρ = 0.808, respectively). There were differences between ACL size on MRI and its actual size: length, 12.4 mm (range, 9.7-15.3 mm) vs 13.8 (10.6-17.8) (P < .001); width, 8.8 mm (range, 7.0-12.1 mm) vs 7.2 (5.8-10.4) (P < .001). Based on sex, there were also differences between the size per MRI and the actual size (P < .001 for all): length in men, 12.6 mm (range, 10.9-15.3 mm) vs 14.2 (12.3-17.8); length in women, 12.4 mm (range, 9.7-14.5 mm) vs 13.7 (10.6-15.8); width in men, 9.3 mm (range, 8.0-12.1 mm) vs 7.6 (5.8-10.4); width in women, 8.7 mm (range, 7.0-10.4 mm) vs 7.2 (5.8-9.7). The actual length of the ACL tibial footprint could be predicted by its length on MRI and sex (R2 = 0.83, P < .001). Similarly, actual width could be predicted by the width on MRI and sex (R2 = 0.75, P < .001). All intraclass correlation coefficients were >0.8, indicating good reliability. Conclusion: Measurements of the size of the ACL tibial footprint on MRI showed strong correlation with its actual size. Prediction equations showed good concordance correlation coefficients. [ABSTRACT FROM AUTHOR]

Background: The critical shoulder angle (CSA) is the angle created between the superior and inferior bone margins of the glenoid and the most lateral border of the acromion. A few studies recently investigated the relation between CSA and functional outcomes after rotator cuff repair. However, there is a lack of research investigating the effect of CSA on postoperative tendon integrity after rotator cuff repair. Purpose: To assess the effects of the CSA on postoperative tendon integrity after rotator cuff repair. Study Design: Cohort study; Level of evidence, 3. Methods: All patients who underwent rotator cuff repair for full-thickness supraspinatus tears by 1 senior surgeon between January 2010 and January 2014 were included in this study. All patients had standardized anteroposterior shoulder radiographs the day before surgery. CSA and acromial index (AI) were measured. AI was derived by measuring the distance from the glenoid plane to the lateral border of the acromion and dividing it by the distance from the glenoid plane to the lateral aspect of the humeral head. Functional scores—including American Shoulder and Elbow Surgeons shoulder evaluation form, modified University of California at Los Angeles score, Constant-Murley score, and visual analog scale for pain—were used to evaluate shoulder function at a minimum follow-up of 2 years. Meanwhile, magnetic resonance imaging examinations were performed to evaluate rotator cuff integrity according to the Sugaya method and the signal/noise quotient (SNQ) of the rotator cuff tendon. Results: A total of 90 patients were included in this study: 42 patients with a single-row repair and 48 with a double-row repair. There was a significant positive correlation between CSA or AI and tendon SNQ. On the basis of CSA, the patients were divided into 2 groups: large CSA (>38°) and control (CSA ≤38°). At final follow-up, the large CSA group and the control CSA group demonstrated no significant differences in American Shoulder and Elbow Surgeons, University of California at Los Angeles, Constant, and visual analog scale scores. Postoperative magnetic resonance imaging revealed that the large CSA group had 9 cases of retear, with a significantly higher retear rate than the control group (15% vs 0%, P = .03). Furthermore, the tendon SNQ of the large CSA group was significantly greater than that of the control group. Conclusion: CSA did not appear to influence postoperative functional outcomes, while those in the large CSA group had poor tendon integrity after rotator cuff repair. These findings indicate that a large CSA is associated with an increased risk of rotator cuff tendon retear after repair. [ABSTRACT FROM AUTHOR]

Background: Meniscus injuries and associated meniscectomies cause patients long-term pain and discomfort and can lead to joint deterioration. Purpose: To evaluate a collagen-hyaluronan sponge reinforced with synthetic resorbable polymer fiber for total meniscus reconstruction in a long-term ovine model. Study Design: Controlled laboratory study. Methods: Eleven skeletally mature sheep were implanted with the total meniscus scaffold. At 2 years, explants were evaluated biologically (radial/circumferential histology, immunofluorescence) and mechanically (compression, tension), and articular surfaces were examined for damage. Results: The fiber-reinforced scaffold induced formation of functional neomeniscus tissue that was intact in 8 of 11 animals. The implant was remodeled into organized circumferentially aligned collagen bundles to resist meniscus hoop stresses. Moreover, type II collagen and proteoglycan deposition near the inner margin suggested a direct response to compressive stresses and confirmed fibrocartilage formation. Cartilage damage was observed, but end-stage (severe) joint deterioration associated with meniscectomy was avoided, even with limitations regarding the ovine surgical procedure and postoperative care. Conclusion: A fiber-reinforced total meniscus replacement device induces formation of functional neomeniscus tissue that has the potential to prevent catastrophic joint deterioration associated with meniscectomy. Clinical Relevance: An off-the-shelf meniscus device that can be remodeled into functional tissue and thus prevent or delay the onset of osteoarthritis could address a widespread clinical need after meniscus injury. [ABSTRACT FROM AUTHOR]

Background: Patients with partial-thickness rotator cuff tears (PTRCTs) can be treated nonoperatively and/or undergo operative treatment, but the ideal time for surgical intervention is unclear. Purpose: To compare the results of immediate arthroscopic rotator cuff repair with repair after 6 months of nonoperative care of PTRCTs involving more than 50% of the tendon thickness. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: The authors prospectively randomized and analyzed 78 consecutive patients diagnosed with either isolated bursal-side or articular-side PTRCTs (supraspinatus only). Group 1 (n = 44) received immediate rotator cuff repair. Group 2 (n = 34) received delayed rotator cuff repair after 6 months of nonoperative treatment. The American Shoulder and Elbow Surgeons (ASES) Score, Constant score, visual analog scale (VAS) for pain, and range of motion at initial visit; months 3, 6, and 12 postoperatively; and the last visit after 24 months were used for the evaluation. Cuff integrity was assessed with magnetic resonance imaging at 12 months postoperatively. Results: There were no significant differences in age, sex (18/26 vs 13/21, male/female), symptom duration, composition of PTRCTs, or clinical outcomes between groups 1 and 2 (P > .05). In group 2, 10 patients voluntarily dropped out from the study due to improvement of symptoms during the 6 months of preoperative nonoperative treatment. The mean follow-up period in groups 1 and 2 was 31.9 ± 1.5 months and 37.0 ± 2.2 months, respectively. At the end of the study, both groups showed significant improvements in terms of functional scores and pain VAS scores compared with the initial period. There were no significant differences between the 2 groups, except for lower pain VAS score and higher ASES Score in group 2 at 6 months postoperatively. At 12 months postoperatively, 1 patient from group 1 and 2 patients from group 2 experienced a retear. Conclusion: Both immediate surgical repair and delayed repair after nonsurgical care for PTRCTs were effective in improving clinical outcomes, and there was a very low incidence of retears in both groups. However, at 6 months postoperatively, superior functional outcomes were observed in the delayed repair group compared with the immediate repair group. A trial period of preoperative nonsurgical care is reasonable, and immediate surgical repair is not crucial for the treatment of PTRCT. [ABSTRACT FROM AUTHOR]

Background: There is currently no consensus regarding the amount of posterior glenoid bone loss that is considered critical. Critical bone loss is defined as the amount of bone loss that occurs in which an isolated labral repair will not sufficiently restore stability. Purpose: The purpose is to identify the critical size of the posterior defect. Study Design: Controlled laboratory study. Methods: Eleven cadaveric shoulders were tested. With the use of a custom robot device, a 50-N compressive force was applied to the glenohumeral joint, and the peak force that was required to translate the humeral head posteriorly and the lateral displacement that occurred with translation were measured. The defect size was measured as a percentage of the glenoid width. Testing was performed in 11 conditions: (1) intact glenoid and labrum, (2) simulated reverse Bankart lesion, (3) the reverse Bankart lesion repaired, (4) a 10% defect, (5) the reverse Bankart lesion repaired, (6) a 20% defect, (7) the reverse Bankart lesion repaired, (8) a 30% defect, (9) the reverse Bankart lesion repaired, (10) a 40% defect, and (11) the reverse Bankart repaired. Results: Force and displacement decreased as the size of the osseous defect increased. The mean peak force that occurred with posterior displacement in specimens with a glenoid defect ≥20% and a reverse Bankart repair (13 ± 9 N) was significantly lower than the peak force that occurred in specimens with an isolated reverse Bankart repair (22 ± 10 N) (P = .0451). In addition, the mean lateral displacement was significantly less in the specimens with a 20% glenoid defect and a reverse Bankart repair (0.61 ± 0.57 mm) compared with the lateral displacement that occurred in specimens with an isolated reverse Bankart repair (1.6 ± 0.78 mm) (P = .0058). Conclusion: An osseous defect that is ≥20% of the posterior glenoid width remains unstable after isolated reverse Bankart repair. Clinical Relevance: A bony restoration procedure of the glenoid may be necessary in shoulders with a posterior glenoid defect that is ≥20% of the glenoid width. [ABSTRACT FROM AUTHOR]

Background: Meaningful change scores in the Knee injury and Osteoarthritis Outcome Score (KOOS) in patients undergoing anterior cruciate ligament (ACL) reconstruction have not yet been established. Purpose: To define the minimal important change (MIC) for the KOOS after ACL reconstruction. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: KOOS and anchor questions with 7-point scales ranging from “better, an important improvement” to “worse, an important worsening” were completed postoperatively by randomly chosen participants from the Norwegian Knee Ligament Registry. Presurgery KOOS scores were retrieved from the registry. The MIC for improvement was calculated with anchor-based approaches using the predictive modeling method adjusted for the proportion of improved patients, the mean change method, and the receiver operating characteristic (ROC) method. Results: Complete data for at least one of the KOOS subscales were obtained from 542 (45.3%) participants. Predictive modeling MIC values were 12.1 for the KOOS subscales of Sport and Recreational Function and 18.3 for Knee-Related Quality of Life. These values aid in interpreting within-group improvement over time and can be used as responder criteria when comparing groups. The corresponding and much lower values for the subscales of Pain (2.5), Symptoms (–1.2), and Activities of Daily Living (2.4) are the results from patients reporting, on average, only mild problems with these domains preoperatively. Although 4% to 10% of patients reported subscale-specific worsening, MIC deterioration calculations were not possible. The ROC MIC values were associated with high degrees of misclassification. Values obtained by the mean change method were considered less reliable because these estimates are derived from subgroups of patients. Average KOOS change scores were approximately similar for patients reporting acceptable symptoms postoperatively and patients reporting important improvements on the anchor items after surgery. Conclusion: KOOS users should apply subscale-specific cutoffs for meaningful improvement. Our results confirm using the subscales of Sport and Recreational Function and Knee-Related Quality of Life as primary patient-reported outcomes after ACL reconstruction. The predictive modeling approach gave the most robust estimates of MIC values. Our data suggest that reporting acceptable symptoms postoperatively corresponds to reporting an important improvement after ACL reconstruction. [ABSTRACT FROM AUTHOR]

Background: The meniscus plays an important role in knee joint diseases such as osteoarthritis (OA). Meniscal injuries can be accompanied by joint catabolic events initiated by inflammation, leading to articular cartilage destruction, but the cellular events responsible for intrinsic meniscal injury and the extracellular matrix changes necessary for meniscal degradation are not well known. Purpose: To explore the cellular and matrix-related changes of menisci based on a mouse OA model of anterior cruciate ligament transection (ACLT). Study Design: Controlled laboratory study. Methods: A mouse ACLT OA model was established by transection of anterior cruciate ligaments on the right knee joints of 8-week-old male (n = 34) and female (n = 34) C57 mice. The knee joints were collected at 1, 2, 4, and 8 weeks after ACLT surgery, and the meniscal changes were analyzed by radiography, histology, immunohistochemistry, immunoblot, and quantitative real-time polymerase chain reaction. Results: The deterioration of menisci was more extensive than that of articular cartilage and subchondral bone at 4 weeks after ACLT surgery. The rapid loss of collagen II and Sox9 in chondrocyte-like cells in the white-white zone of menisci was confirmed, and the activation of potential meniscus progenitor cells and chondroblasts was identified based on the increase of CD90, CD105, and Runx2. Further, the intrinsic inflammation in the bone marrow–like zone of menisci was activated by enhancement of dendritic cells (CD11c+), T cells (CD3+), and macrophages (F4/80+) with the increase of the inflammatory factors interleukin 1β and tumor necrosis factor α. Finally, the extracellular matrix events involving changes in chemokines, increases of matrix proteases (matrix metalloproteinases and ADAMTS5), and decreases of lysyl oxidase family were elucidated. Conclusion: ACLT-induced meniscal changes not only could explain the contribution of the meniscus to the progress of OA but also could provide a cue for initiation of preventive treatments in the early stages of OA. Clinical Relevance: This study provides support for better protection of menisci in ACL injury–induced conditions such as OA and indicates that menisci should be considered in the development of clinical pharmacological interventions. [ABSTRACT FROM AUTHOR]

Background: Anterior cruciate ligament (ACL) tears are associated with the development of knee osteoarthritis despite ACL reconstruction surgery. However, little evidence is available to determine which patients will develop symptomatic knee osteoarthritis. Purpose: To determine if preoperative outcome measures—KOOS (Knee injury and Osteoarthritis Outcome Score) and SF-36 (36-item Short Form Health Survey)—were associated with the development of a symptomatic knee 7 years after ACL reconstruction. A secondary goal was to examine the relationship between imaging evidence of knee osteoarthritis and development of knee pain. Study Design: Case-control study; Level of evidence, 3. Methods: Prospectively collected data from 72 patients were reviewed with 7-year follow-up after unilateral ACL reconstruction. Patients were divided into symptomatic and asymptomatic groups based on the previously defined KOOS pain ≤72. Demographic variables and preoperative KOOS and SF-36 scores were compared between groups. Radiographic and magnetic resonance imaging data were used to evaluate differences in joint space width, Osteoarthritis Research Society International radiographic score, and the Whole-Organ Magnetic Resonance Imaging Score between groups. Univariate and multivariate analyses were performed to identify potential predictors of pain at 7-year follow-up. Wilcoxon sum rank and t tests were used to compare imaging findings between the symptomatic and asymptomatic patients at 7 years. Results: According to KOOS pain, 7 of the 72 patients available at 7-year follow-up formed the symptomatic group. No differences were found between groups in regard to demographic variables or intraoperative findings. In multivariate analysis, lower preoperative scores for KOOS sports/recreation (P = .005) and SF-36 mental health (P = .025) were associated with a painful knee at 7 years, with increased odds of 82% and 68% per 10-unit decrease, respectively. The Whole-Organ Magnetic Resonance Imaging Score at 7 years showed evidence of osteoarthritic changes in the symptomatic group as compared with the asymptomatic group (P = .047). However, there were no significant differences in the Osteoarthritis Research Society International radiographic score (P = .051) or joint space width (P = .488) between groups. Conclusion: Lower preoperative KOOS and SF-36 scores were associated with those patients who developed symptomatic knee osteoarthritis 7 years after ACL reconstruction. [ABSTRACT FROM AUTHOR]

Background: The creation of a single patient-reported outcome (PRO) platform validated across hip preservation, osteoarthritis (OA), and total hip arthroplasty (THA) populations may reduce barriers and streamline the routine collection of PROs in clinical practice. As such, the purpose of this study was to determine if augmenting the Hip disability and Osteoarthritis Outcome Score–Joint Replacement (HOOS, JR) with additional HOOS questions would result in a PRO platform that could be used across a wider spectrum of hip patient populations. Hypothesis: The HOOS, JR would demonstrate a notable ceiling effect, but by augmenting the HOOS, JR with additional HOOS questions, a responsive PRO platform could be created. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Using preoperative and postoperative HOOS responses from a sample of 304 patients undergoing periacetabular osteotomy (PAO), additional items were identified to augment the HOOS, JR. The psychometric properties of a newly created PRO tool (HOOSglobal) were then compared with the HOOS, JR and other PRO instruments developed for patients with hip OA and/or undergoing THA. Results: By augmenting the HOOS, JR with 2 additional questions, the HOOSglobal was more responsive than all other included PRO tools and had significantly fewer maximum postoperative scores than the HOOS, JR (P < .0001), HOOS–Physical Function Short form (P < .0001), Western Ontario and McMaster Universities Osteoarthritis Index (P = .02), University of California, Los Angeles activity scale (P = .0002), and modified Harris Hip Score (P = .04). The postoperative HOOSglobal score threshold associated with patients achieving the patient acceptable symptom state (PASS) was 62.5. Conclusion: The HOOSglobal is a valid and responsive PRO tool after PAO and may potentially provide the orthopaedic community with a PRO platform to be used across hip-related subspecialties. For patients undergoing PAO, a postoperative HOOSglobal score ≥62.5 was associated with patients achieving the PASS. [ABSTRACT FROM AUTHOR]

Background: Superior capsular reconstruction (SCR) was recently introduced as a treatment for irreparable superior rotator cuff tears in younger patients. Purpose/Hypothesis: The purpose was to assess the biomechanical strength of 3 methods for fixation of the graft to the glenoid for SCR. It was hypothesized that a 4-anchor technique would provide greater load to failure than 3-anchor techniques. Study Design: Controlled laboratory study. Methods: Thirty-six cadaveric specimens were randomized into 3 groups of previously established glenoid-side graft fixation techniques: (1) three 3.5-mm knotless screw-in anchors, (2) three 3.0-mm knotless push-in anchors, and (3) a 4-anchor hybrid construct with two 3.0-mm knotted push-in anchors and two 2.9-mm knotless push-in anchors. The repairs were cyclically loaded at 0.5 Hz from 10 to 200 N, then pulled to failure. Elongation, stiffness, maximum load at failure, and mode of failure were recorded and calculated. Results: There were no significant differences in graft elongation or stiffness among the 3 techniques (P > .37 and P > .26, respectively). Maximum load to failure was significantly greater in technique 1 (mean ± SD, 427.85 ± 119.70 N) than technique 3 (319.5 ± 57.60 N) (P = 0.024). There were no significant differences in load to failure between techniques 1 and 2 or between techniques 2 and 3. Conclusion: Glenoid-side graft fixation with 3 threaded 3.5-mm suture anchors showed a significant superior pull-out strength when compared with a 4-anchor hybrid technique and thus might be recommended in SCR for patients with irreparable superior rotator cuff tears to achieve maximum stability. Clinical Relevance: SCR presents a novel alternative for treatment of irreparable superior rotator cuff tears in younger patients. Glenoid fixation is essential to provide adequate fixation of the graft to prevent the humeral head from rising and to restore normal biomechanics. [ABSTRACT FROM AUTHOR]

Background: Anterior cruciate ligament (ACL) grafts that are placed for reconstruction are subject to complex forces. Current “anatomic” ACL reconstruction techniques may result in greater in situ graft forces. The biological effect of changing magnitudes of ACL graft force on graft-tunnel osseointegration is not well understood. Purpose: The research objective is to determine how mechanical force on the ACL graft during knee motion affects tendon healing in the tunnel. Study Design: Controlled laboratory study. Methods: Male rats (N = 120) underwent unilateral ACL reconstruction with a soft tissue flexor tendon autograft. ACL graft force was modulated by different femoral tunnel positions at the time of surgery to create different graft force patterns with knee motion. External fixators were used to eliminate graft load during cage activity. A custom knee flexion device was used to deliver graft load through controlled daily knee motion. Graft-tunnel healing was then assessed via biomechanical, micro–computed tomography, and histological analyses. Results: ACL graft-tunnel healing was sensitive to dynamic changes in graft forces with postoperative knee motion. High ACL graft force with joint motion resulted in early inferior ACL graft load to failure as compared with knees that had low-force ACL grafts and joint motion and knees that were immobilized (mean ± SD: 5.50 ± 2.30 N vs 9.91 ± 3.54 N [P = .013] and 10.90 ± 2.8 N [P = .001], respectively). Greater femoral bone volume fraction was seen in immobilized knees and knees with low-force ACL grafts when compared with high-force ACL grafts at 3 and 6 weeks. Conclusion: The authors were able to demonstrate that ACL graft-tunnel incorporation is sensitive to dynamic changes in ACL graft force with joint motion. Early high forces on the ACL graft appear to impair graft-tunnel osseointegration. Clinical Relevance: Current “anatomic” techniques of ACL reconstruction may result in greater graft excursion and force with knee motion. Our results suggest that the postoperative rehabilitation regimen may need to be modified during the early phase of healing to protect the reconstruction. [ABSTRACT FROM AUTHOR]

Background: The plantaris tendon (PT) has been thought to contribute to symptoms in a proportion of patients with Achilles midportion tendinopathy, with symptoms improving after PT excision. Hypothesis: There is compression and differential movement between the PT and Achilles tendon (AT) during ankle plantarflexion and dorsiflexion. Study Design: Descriptive laboratory study. Methods: Eighteen fresh-frozen cadaveric ankles (mean ± SD age: 35 ± 7 years, range = 27-48 years; men, n = 9) were mounted in a customized testing rig, where the tibia was fixed but the forefoot could be moved freely. A Steinmann pin was drilled through the calcaneus, enabling a valgus torque to be applied. The soleus, gastrocnemius, and plantaris muscles were loaded with 63 N with a weighted pulley system. The test area was 40 to 80 mm above the os calcis, corresponding to where the injury is observed clinically. Medially, the AT and PT were exposed, and a calibrated flexible pressure sensor was inserted between the tendons. Pressure readings were recorded with the ankle in full dorsiflexion, full plantarflexion, and plantargrade and repeated in these positions with a 5 N·m torque, simulating increased hindfoot valgus. The pressure sensor was removed and the PT and AT marked with ink at the same level, with the foot held in neutral rotation and plantargrade. Videos and photographs were taken to assess differential motion between the tendons. After testing, specimens were dissected to identify the PT insertion. One-way analysis of variance and paired t tests were performed to make comparisons. Results: The PT tendons with an insertion separate from the AT demonstrated greater differential motion through range (14 ± 4 mm) when compared with those directly adherent to the AT (2 ± 2 mm) (P < .001). Mean pressure between the PT and AT rose in terminal plantarflexion for all specimens (P < .001) and was more pronounced with hindfoot valgus (P < .001). Conclusion: The PT inserting directly into the calcaneus resulted in significantly greater differential motion as compared with the AT. Tendon compression was elevated in terminal plantarflexion, suggesting that adapting rehabilitation tendon-loading programs to avoid this position may be beneficial. Clinical Relevance: The insertion pattern of the PT may be a factor in plantaris-related midportion Achilles tendinopathy. Terminal range plantarflexion and hindfoot valgus both increased AT and PT compression, suggesting that these should be avoided in this patient population. [ABSTRACT FROM AUTHOR]

Background: Insertion force has been shown to significantly reduce chondrocyte viability during osteochondral allograft transplantation. How graft size influences the required insertion force and chondrocyte viability has yet to be determined. Hypothesis/Purpose: The purpose was to characterize how graft size influences insertion force requirements and chondrocyte viability during osteochondral transplantation. The hypothesis was that larger grafts would require greater force and reduce chondrocyte viability. Study Design: Controlled laboratory study. Methods: Four graft sizes—15 × 5 mm, 15 × 10 mm, 25 × 5 mm, and 25 × 10 mm (diameter × depth)—were harvested from 13 thawed fresh-frozen human cadaveric distal femurs. Average, maximum, and cumulative force and number of impacts were recorded for 44 grafts by a surgical mallet embedded with a calibrated force sensor. In a separate experiment, fresh osteochondral tissues were subjected to mechanical loading. To capture a range of clinically important forces, categories were selected to correspond to impaction force data. Chondrocyte viability was assessed with confocal laser microscopy and live/dead staining. Results: Total force for all grafts averaged 4576 N. Median number of impacts for all grafts was 20 (range, 7-116). The mean number of impacts for 5-mm-deep grafts was 14.2 (95% CI, 10.8-18.6), as compared with 26.3 (95% CI, 19.9-34.4) for 10-mm-deep grafts (P < .001). The mean cumulative force for 5-mm-deep grafts was 2128 N (95% CI, 1467-3087), as opposed to 4689 N (95% CI, 3232-6803) for 10-mm-deep grafts (P = .001). For every 1 mm in graft depth, an average of 13.1% (95% CI, 6.2%-20.3%) more impacts are required when controlling for diameter and density (P < .001). For every 1 mm in graft depth, the force required increases on average by 17.1% (95% CI, 7.7%-27.4%) when controlling for diameter and density (P = .001). There was a significant reduction in chondrocyte viability for the forces required for graft thickness values >10 mm. Only forces associated with graft thickness <10 mm had chondrocyte viabilities consistently >70%. Conclusion: Insertion force increases significantly with increasing graft depth. Controlling for diameter and bone density, a 1-mm increase in graft depth is associated with 13.1% more impacts and 17.1% more force. Chondrocyte viability was significantly reduced to <70% at average forces associated with grafts thicker than 10 mm. Clinical Relevance: Based on the current data, graft depth is an important consideration for surgeons when sizing osteochondral allograft transplant for chondral lesions of the knee. [ABSTRACT FROM AUTHOR]

Background: Persistent clinical instability after anterior cruciate ligament (ACL) reconstruction may be associated with injury to the anterolateral structures and has led to renewed interest in anterolateral extra-articular procedures. The influence of these procedures on knee kinematics is controversial. Purpose/Hypothesis: The purpose was to investigate the biomechanical properties of anatomic anterolateral ligament (ALL) reconstruction and a modified Lemaire procedure (lateral extra-articular tenodesis [LET]) in combination with ACL reconstruction as compared with isolated ACL reconstruction in the setting of deficient anterolateral structures (ALL and Kaplan fibers). It was hypothesized that both techniques would reduce tibial internal rotation when combined with ACL reconstruction in the setting of anterolateral structure deficiency. Study Design: Controlled laboratory study. Methods: A 6 degrees of freedom robotic system was used to assess tibial internal rotation, a simulated pivot-shift test, and anterior tibial translation in 10 paired fresh-frozen cadaveric knees. The following states were tested: intact; sectioned ACL, ALL, and Kaplan fibers; ACL reconstruction; and an anterolateral extra-articular procedure (various configurations of ALL reconstruction and LET). Knees within a pair were randomly assigned to either ALL reconstruction or LET with a graft tension of 20 N and a randomly assigned fixation angle (30° or 70°). ALL reconstruction was then repeated and secured with a graft tension of 40 N. Results: In the setting of deficient anterolateral structures, ACL reconstruction was associated with significantly increased residual laxity for tibial internal rotation (up to 4°) and anterior translation (up to 2 mm) laxity as compared with the intact state. The addition of ALL reconstruction or LET after ACL reconstruction significantly reduced tibial internal rotation in most testing scenarios to values lower than the intact state (ie, overconstraint). Significantly greater reduction in laxity with internal rotation and pivot-shift testing was found with the LET procedure than ALL reconstruction when compared with the intact state. Combined with ACL reconstruction alone, both extra-articular procedures restored anterior tibial translation to values not significantly different from the intact state with most testing scenarios (usually within 1 mm). Conclusion: Residual laxity was identified after isolated ACL reconstruction in the setting of ALL and Kaplan fiber deficiency, and the combination of ACL reconstruction in this setting with either ALL reconstruction or the modified Lemaire LET procedure resulted in significant reductions in tibiofemoral motion at most knee flexion angles, although overconstraint was also identified. ALL reconstruction and LET restored anterior tibial translation to intact values with most testing states. Clinical Relevance: ALL reconstruction and lateral extra-articular tenodesis have been described in combination with intra-articular ACL reconstruction to address rotational laxity. This study demonstrated that both procedures resulted in significant reductions of tibial internal rotation versus the intact state independent of graft tension or fixation angle, although anterior tibial translation was generally restored to intact values. The influence of overconstraint with anterolateral knee reconstruction procedures has not been fully evaluated in the clinical setting and warrants continued evaluation based on the findings of this biomechanical study. [ABSTRACT FROM AUTHOR]

Background: Although image analysis has shown that the outside-in (OI) technique is associated with different femoral tunnel geometry than the transportal (TP) technique in anatomic anterior cruciate ligament (ACL) reconstruction, it is not known whether clinical results differ between the 2 techniques. Purpose: To compare clinical results, second-look arthroscopic findings, and magnetic resonance imaging (MRI) findings between the TP and OI techniques in anatomic double-bundle (DB) ACL reconstruction. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: From November 2010 to March 2013, 128 patients were enrolled in this study and were randomly assigned to either the TP group (64 patients) or the OI group (64 patients), and DB ACL reconstructions were performed. At the minimum 2-year follow-up (34.9 ± 10.9 months), 111 patients (86.7%) were evaluated with multiple clinical scores and stability tests (KT-2000 arthrometer, Lachman test, and pivot-shift test). Ninety-three knees were evaluated for graft continuity, graft tension, and synovialization by use of second-look arthroscopy. Seventy-eight knees were evaluated on MRI for graft continuity, femoral graft tunnel healing, and graft signal/noise quotient (SNQ). The primary outcome was KT-2000 arthrometer results. Results were compared between the TP and OI groups. Results: No significant differences were found between the 2 groups in terms of KT-2000 arthrometer results, which was the primary outcome, and other clinical results, with the exception of the postoperative functional test of International Knee Documentation Committee (IKDC) objective score. The ratio of grade A and B on the postoperative functional test of IKDC objective score was significantly larger for the OI group (51/58) than the TP group (36/53) (P = .005). The second-look arthroscopic findings were not significantly different between the 2 groups in either bundle (P > .05). In addition, MRI findings did not differ significantly between the 2 groups (P > .05). Conclusion: With the exception of the functional test of IKDC objective score, we found that clinical results, second-look arthroscopic findings, and MRI findings did not differ significantly between the OI and TP techniques for anatomic ACL reconstruction, although femoral tunnel geometries differed significantly between the 2 techniques. [ABSTRACT FROM AUTHOR]

Background: Anterior cruciate ligament (ACL) injury increases risk for posttraumatic knee osteoarthritis (OA). Quantitative ultrashort echo time enhanced T2* (UTE-T2*) mapping shows promise for early detection of potentially reversible subsurface cartilage abnormalities after ACL reconstruction (ACLR) but needs further validation against established clinical metrics of OA risk such as knee adduction moment (KAM) and mechanical alignment. Hypothesis: Elevated UTE-T2* values in medial knee cartilage 2 years after ACLR correlate with varus alignment and higher KAM during walking. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Twenty patients (mean age, 33.1 ± 10.5 years; 11 female) 2 years after ACLR underwent 3.0-T knee magnetic resonance imaging (MRI), radiography, and gait analysis, after which mechanical alignment was measured, KAM during walking was calculated, and UTE-T2* maps were generated. The mechanical axis and the first and second peaks of KAM (KAM1 and KAM2, respectively) were tested using linear regressions for correlations with deep UTE-T2* values in the central and posterior medial femoral condyle (cMFC and pMFC, respectively) and central medial tibial plateau (cMTP). UTE-T2* values from ACL-reconstructed patients were additionally compared with those of 14 uninjured participants (mean age, 30.9 ± 8.9 years; 6 female) using Mann-Whitney U and standard t tests. Results: Central weightbearing medial compartment cartilage of ACL-reconstructed knees was intact on morphological MRI. Mean UTE-T2* values were elevated in both the cMFC and pMFC of ACL-reconstructed knees compared with those of uninjured knees (P = .003 and P = .012, respectively). In ACL-reconstructed knees, UTE-T2* values of cMFC cartilage positively correlated with increasing varus alignment (R = 0.568). Higher UTE-T2* values in cMFC and cMTP cartilage of ACL-reconstructed knees also correlated with greater KAM1 (R = 0.452 and R = 0.463, respectively) and KAM2 (R = 0.465 and R = 0.764, respectively) and with KAM2 in pMFC cartilage (R = 0.602). Conclusion: Elevated deep UTE-T2* values of medial knee cartilage 2 years after ACLR correlate with 2 clinical markers of increased risk of medial knee OA. These results support the clinical utility of MRI UTE-T2* for early diagnosis of subsurface cartilage abnormalities. Longitudinal follow-up of larger cohorts is needed to determine the predictive and staging potential of UTE-T2* for posttraumatic OA. [ABSTRACT FROM AUTHOR]

Background: Corticosteroid injection is a common treatment for frozen shoulder, but controversy still exists regarding the injection site with the best outcome. Hypothesis: To treat the frozen shoulder in the freezing stage with corticosteroid injection, a single injection into the rotator interval (RI) could yield better effects in terms of improvement in pain, passive range of motion (ROM), and function than would an injection into the intra-articular (IA) or subacromial (SA) space. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Patients with primary frozen shoulder in the freezing stage were randomized into 3 groups: RI injection, IA injection, or SA injection with corticosteroid. Clinical outcomes were documented at baseline and at 4, 8, and 12 weeks after intervention, including visual analog scale (VAS) for pain; passive ROM measurements, including external rotation, internal rotation, forward flexion, and abduction; and evaluation with the Disability of Arm, Hand, and Shoulder (DASH) score and Constant score. Results: There were no significant differences in the basic properties of the 3 groups (27 in RI group, 24 in IA group, and 26 in SA group) before injection. Improvements in pain VAS, passive ROM, Constant score, and DASH score were faster and significant in the RI group from 4 weeks after injection, followed by those in the IA group. Passive ROM decreased and DASH score did not change significantly in the SA group, although pain VAS and Constant score improved significantly. Conclusion: To treat frozen shoulder in the freezing stage with corticosteroid injection, a single injection into the RI yielded better effects in terms of improvement in pain, passive ROM, and function than did injections into the IA or SA space. [ABSTRACT FROM AUTHOR]

Background: Insufficient cell numbers still present a challenge for articular cartilage repair. Converting heterotopic auricular chondrocytes by extracellular matrix may be the solution. Hypothesis: Specific extracellular matrix may convert the phenotype of auricular chondrocytes toward articular cartilage for repair. Study Design: Controlled laboratory study. Methods: For in vitro study, rabbit auricular chondrocytes were cultured in monolayer for several passages until reaching status of dedifferentiation. Later, they were transferred to chondrogenic type II collagen (Col II)–coated plates for further cell conversion. Articular chondrogenic profiles, such as glycosaminoglycan deposition, articular chondrogenic gene, and protein expression, were evaluated after 14-day cultivation. Furthermore, 3-dimensional constructs were fabricated using Col II hydrogel-associated auricular chondrocytes, and their histological and biomechanical properties were analyzed. For in vivo study, focal osteochondral defects were created in the rabbit knee joints, and auricular Col II constructs were implanted for repair. Results: The auricular chondrocytes converted by a 2-step protocol expressed specific profiles of chondrogenic molecules associated with articular chondrocytes. The histological and biomechanical features of converted auricular chondrocytes became similar to those of articular chondrocytes when cultivated with Col II 3-dimensional scaffolds. In an in vivo animal model of osteochondral defects, the treated group (auricular Col II) showed better cartilage repair than did the control groups (sham, auricular cells, and Col II). Histological analyses revealed that cartilage repair was achieved in the treated groups with abundant type II collagen and glycosaminoglycans syntheses rather than elastin expression. Conclusion: The study confirmed the feasibility of applying heterotopic chondrocytes for cartilage repair via extracellular matrix–induced cell conversion. Clinical Relevance: This study proposes a feasible methodology to convert heterotopic auricular chondrocytes for articular cartilage repair, which may serve as potential alternative sources for cartilage repair. [ABSTRACT FROM AUTHOR]

Background: Limited information in basic science and clinical trials exists to determine if ligament healing may be accelerated with the use of biological adjuvants, such as platelet-rich plasma (PRP). However, there has been widespread acceptance of PRP for use in clinical practice, despite an inadequate understanding of its biological mechanism of action. Purpose: To determine whether a single dose of PRP could accelerate ligament healing and correspondingly improve histological characteristics and biomechanical properties when injected immediately postoperatively into the injured medial collateral ligament (MCL) of New Zealand White rabbits. Study Design: Controlled laboratory study. Methods: Eighty skeletally mature New Zealand White rabbits (160 knees) were used. The MCL was torn midbody to simulate a grade 3 tear. After an acute injury of the MCL, the administration of autologous PRP at 3 different platelet concentrations (0 million/uL, platelet-poor plasma [PPP]; 0.6 million/uL, 2 times the baseline [2× PRP]; and 1.2 million/uL, 4 times the baseline [4× PRP]) was performed and compared with a saline injection control in the contralateral knee. Histological analysis and a biomechanical endpoint characterization were utilized to assess ligamentous healing and compare it to a sham surgery group. Results: The PPP (P = .001) and 4× PRP (P = .002) groups had a significantly lower collagen subscore than the sham surgery group. No other differences were observed among the treatment groups, including the vascularity subscore and overall ligament tissue maturity index score. Compared with saline-injected contralateral knees, the maximum load for PPP and 2× PRP was not significantly different (P = .788 and .325, respectively). The maximum load and stiffness for knees treated with 4× PRP were significantly less than for the saline-treated contralateral knees (P = .006 and .001, respectively). Conclusion: One single dose of PPP or 2× PRP at the time of injury did not improve ligament healing. In addition, 4× PRP negatively affected ligament strength and histological characteristics at 6 weeks after the injury. Clinical Relevance: The current practice of treating knee ligament injuries with PRP may not improve healing at low doses of PRP. The decreased mechanical properties and histological appearance of the torn MCL suggest that high doses of PRP decrease the quality of repair tissue. Further in vivo studies are necessary to determine the dosing and timing of PRP administration after a ligament injury before the widespread use of PRP to treat ligament injuries is recommended. [ABSTRACT FROM AUTHOR]

Background: A hamstring autograft is commonly used in anterior cruciate ligament (ACL) reconstruction (ACLR); however, there is evidence to suggest that the tendons harvested may contribute to medial knee instability. Hypothesis: We tested the hypothesis that the gracilis (G) and semitendinosus (ST) tendons significantly contribute to sagittal, coronal, and/or rotational knee stability in the setting of ACLR with a concurrent partial medial collateral ligament (MCL) injury. Study Design: Controlled laboratory study. Methods: Twelve human cadaveric knees were subject to static forces applied to the tibia including an anterior-directed force as well as varus, valgus, and internal and external rotation moments to quantify laxity at 0°, 30°, 60°, and 90° of flexion. The following ligament conditions were tested on each specimen: (1) ACL intact/MCL intact, (2) ACL deficient/MCL intact, (3) ACL deficient/partial MCL injury, and (4) ACLR/partial MCL injury. To quantify the effect of muscle loads, the quadriceps, semimembranosus, biceps femoris, sartorius (SR), ST, and G muscles were subjected to static loads. The loads on the G, ST, and SR could be added or removed during various test conditions. For each ligament condition, the responses to loading and unloading the G/ST and SR were determined. Three-dimensional positional data of the tibia relative to the femur were recorded to determine tibiofemoral rotations and translations. Results: ACLR restored anterior stability regardless of whether static muscle loads were applied. There was no significant increase in valgus motion after ACL transection. However, when a partial MCL tear was added to the ACL injury, there was a 30% increase in valgus rotation (P < .05). ACLR restored valgus stability toward that of the intact state when the G/ST muscles were loaded. A load on the SR muscle without a load on the G/ST muscles restored 19% of valgus rotation; however, it was still significantly less stable than the intact state. Conclusion: After ACLR in knees with a concurrent partial MCL injury, the absence of loading on the G/ST did not significantly alter anterior stability. Simulated G/ST harvest did lead to increased valgus motion. These results may have important clinical implications and warrant further investigation to better outline the role of the medial hamstrings, particularly among patients with a concomitant ACL and MCL injury. Clinical Relevance: A concurrent ACL and MCL injury is a commonly encountered clinical problem. Knowledge regarding the implications of hamstring autograft harvest techniques on joint kinematics may help guide management decisions. [ABSTRACT FROM AUTHOR]

Background: Fresh osteochondral allografts (OCAs) are limited in availability. The Missouri Osteochondral Allograft Preservation System (MOPS) has been reported to effectively preserve OCAs twice as long as current tissue bank protocols in preclinical studies. Hypothesis: The viable chondrocyte density (VCD) in OCAs preserved for up to 70 days using the MOPS will not be significantly different from day 0, and the VCD in MOPS-preserved OCAs will be significantly higher than for standard tissue bank preservation. Media changes during preservation will significantly improve the VCD. Study Design: Controlled laboratory study. Methods: Femoral condyles harvested from qualified donors (n = 12) were quartered (n = 48), assigned to 1 of 4 treatment groups (tissue bank protocol at 4°C or MOPS at 25°C, with or without media changes), and preserved for 0, 28, 56, or 70 days and assessed for the VCD and histopathological characteristics. In addition, osteochondral explants were created from the femoral condyles of 12 donors (n = 36 explants), assigned to the same groups and time points, and tested for biomechanical properties. Results: MOPS-preserved OCAs maintained the day 0 VCD through 56 days. OCAs stored using current tissue bank protocols had a significantly lower VCD compared with day 0 and the MOPS by day 28. OCA histological and biomechanical properties did not significantly change from day 0 for any group. Conclusion: The MOPS preserved essential OCA viability and quality at significantly higher levels than current tissue bank protocols for at least 56 days after procurement. Clinical Relevance: Improving the viability and duration of OCA preservation provides potential benefits to tissue banks, donor families, surgeons, and patients with respect to tissue use, financial costs, and outcomes. [ABSTRACT FROM AUTHOR]

Background: Variations in femoral and acetabular version are becoming increasingly recognized as contributing factors to the development of hip pain in patients with femoroacetabular impingement (FAI) and hip dysplasia. It is still unknown what the true prevalence of these rotational abnormalities is in this patient population. Purpose: To determine (1) the prevalence of femoral version abnormalities in symptomatic hips with FAI and hip dysplasia, (2) the prevalence of combined abnormalities of femoral and acetabular version in these patients, and (3) which specific hip morphologies are associated with abnormalities of femoral version. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 462 symptomatic patients (538 hips) were included who had hip pain attributed to FAI or hip dysplasia and who presented to our tertiary referral center for hip preservation surgery between 2011 and 2015. We retrospectively examined femoral and acetabular version among 11 subgroups with predefined hip morphologies and compared findings with a control group. The allocation to each subgroup was based on morphologic reference values for femoral head coverage, lateral center edge angle, alpha angle, and neck-shaft angle calculated on plain radiographs. Results: Of the 538 hips included, 52% were found to have abnormal femoral version; severe abnormalities were found in 17%. Severely decreased femoral version (<0°) was found in 5%; moderately decreased femoral version (0°-10°), in 17%; moderately increased femoral version (26°-35°), in 18%; and severely increased femoral version (>35°), in 12%. The most frequent abnormal combination was increased femoral version combined with normal acetabular version (22%). We found significantly lower mean femoral version for the cam-type FAI group (15°) and significantly higher mean femoral version for the Perthes hips (32°; ie, Legg-Calvé-Perthes disease) as compared with the control group (22°). The mean femoral version of the study group was 19°; for male patients, 15°; and for female patients, 22°. Conclusion: Abnormalities in femoral version are highly prevalent in patients with hip pain who are eligible for hip preservation surgery, and severe abnormalities are prevalent in 1 of 6 patients (17%). Based on these results, the evaluation of young patients with hip pain should always include an assessment of femoral version and acetabular version to best decide what treatment approach should be undertaken to optimize outcomes. [ABSTRACT FROM AUTHOR]

Background: Contralateral anterior cruciate ligament (CACL) injury after recovery from a first-time ACL rupture occurs at a high rate in young females; however, little is known about the risk factors associated with bilateral ACL trauma. Hypothesis: The geometric characteristics of the contralateral knee at the time of the initial ACL injury are associated with risk of suffering a CACL injury in these female athletes. Study Design: Case-control study; Level of evidence, 3. Methods: Sixty-two female athletes who suffered their first noncontact ACL injury while participating in sports at the high school or college level were identified, and geometry of the femoral notch, ACL, tibial spines, tibial subchondral bone, articular cartilage surfaces, and menisci of the contralateral, uninjured, knee was characterized in 3 dimensions. We were unable to contact 7 subjects and followed the remaining 55 until either a CACL injury or an ACL graft injury occurred or, if they were not injured, until the date of last contact (mean, 34 months after their first ACL injury). Cox regression was used to identify risk factors for CACL injury. Results: Ten (18.2%) females suffered a CACL injury. Decreases of 1 SD in femoral intercondylar notch width (measured at its outlet and anterior attachment of the ACL) were associated with increases in the risk of suffering a CACL injury (hazard ratio = 1.88 and 2.05, respectively). Likewise, 1 SD decreases in medial-lateral width of the lateral tibial spine, height of the medial tibial spine, and thickness of the articular cartilage located at the posterior region of the medial tibial compartment were associated with 3.59-, 1.75-, and 2.15-fold increases in the risk of CACL injury, respectively. Conclusion: After ACL injury, subsequent injury to the CACL is influenced by geometry of the structures that surround the ACL (the femoral notch and tibial spines). This information can be used to identify individuals at increased risk for CACL trauma, who might benefit from targeted risk-reduction interventions. [ABSTRACT FROM AUTHOR]

Background: Although knees that have undergone anterior cruciate ligament reconstruction (ACLR) often exhibit normal laxity on clinical examination, abnormal kinematic patterns have been observed when the joint is dynamically loaded during whole body activity. This study investigated whether abnormal knee kinematics arise with loading under isolated dynamic movements. Hypothesis: Tibiofemoral and patellofemoral kinematics of ACLR knees will be similar to those of the contralateral uninjured control knee during passive flexion-extension, with bilateral differences emerging when an inertial load is applied. Study Design: Controlled laboratory study. Methods: The bilateral knees of 18 subjects who had undergone unilateral ACLR within the past 4 years were imaged by use of magnetic resonance imaging (MRI). Their knees were cyclically (0.5 Hz) flexed passively. Subjects then actively flexed and extended their knees against an inertial load that induced stretch-shortening quadriceps contractions, as seen during the load acceptance phase of gait. A dynamic, volumetric, MRI sequence was used to track tibiofemoral and patellofemoral kinematics through 6 degrees of freedom. A repeated-measures analysis of variance was used to compare secondary tibiofemoral and patellofemoral kinematics between ACLR and healthy contralateral knees during the passive and active extension phases of the cyclic motion. Results: Relative to the passive motion, inertial loading induced significant shifts in anterior and superior tibial translation, internal tibial rotation, and all patellofemoral degrees of freedom. As hypothesized, tibiofemoral and patellofemoral kinematics were bilaterally symmetric during the passive condition. However, inertial loading induced bilateral differences, with the ACLR knees exhibiting a significant shift toward external tibial rotation. A trend toward greater medial and anterior tibial translation was seen in the ACLR knees. Conclusion: This study demonstrates that abnormal knee kinematic patterns in ACLR knees emerge during a simple, active knee flexion-extension task that can be performed in an MRI scanner. Clinical Relevance: It is hypothesized that abnormal knee kinematics may alter cartilage loading patterns and thereby contribute to increased risk for osteoarthritis. Recent advances in quantitative MRI can be used to detect early cartilage degeneration in ACLR knees. This study demonstrates the feasibility of identifying abnormal ACLR kinematics by use of dynamic MRI, supporting the combined use of dynamic and quantitative MRI to investigate the proposed link between knee motion, cartilage contact, and early biomarkers of cartilage degeneration. [ABSTRACT FROM AUTHOR]

Background: Osteoarthritis of the medial tibiofemoral joint (MTFJ) is prevalent among patients undergoing anterior cruciate ligament reconstruction (ACLR). Magnetic resonance T1ρ and T2 relaxation times provide noninvasive methods to quantify early cartilage degeneration. Altered sagittal-plane gait biomechanics have been observed after ACLR, but their associations with longitudinal changes in MTFJ cartilage T1ρ and T2 remain unclear. Hypothesis/Purpose: To examine whether the peak knee flexion moment (KFM), knee flexion angle (KFA), and vertical ground-reaction force (vGRF) during gait are associated with prospective changes in medial tibiofemoral cartilage T1ρ and T2 in ACL-reconstructed knees and to compare these gait characteristics between patients undergoing ACLR and healthy control participants. We hypothesized that a higher KFM, KFA, and vGRF would be associated with greater increases in cartilage relaxation times and that patients undergoing ACLR would demonstrate altered gait characteristics compared with healthy controls. Study Design: Controlled laboratory study. Methods: Thirty-three patients undergoing ACLR underwent gait analysis before and 6 months and 1 year after ACLR and knee magnetic resonance imaging (MRI) before and 6 months, 1 year, and 2 years after ACLR. Twelve healthy controls underwent knee MRI and gait analysis at baseline and 1 year. Cartilage T1ρ and T2 were calculated for the medial tibia and medial femoral condyle. Linear regressions were used to evaluate associations between gait characteristics and changes in cartilage relaxation times from before ACLR to follow-up time points. Independent t tests were used to compare differences in gait between patients undergoing ACLR and control participants. Results: A higher KFM and KFA before ACLR were related to greater increases in medial femoral condyle T1ρ and T2 at 6 months after ACLR. Similarly, a higher KFM, KFA, and vGRF at 6 months were associated with greater increases in medial tibia and medial femoral condyle T1ρ and T2 at 1 and 2 years after ACLR. Gait characteristics at 1 year were not associated with changes in cartilage relaxation times at 2 years after ACLR. Compared with healthy controls, patients undergoing ACLR demonstrated a lower KFM at 6 months after ACLR. Conclusion/Clinical Relevance: The findings of this study revealed that a higher KFM, KFA, and vGRF during gait, especially at 6 months after ACLR, were associated with greater deterioration of MTFJ cartilage health at later time points. [ABSTRACT FROM AUTHOR]

Background: Although osteochondral autograft transplantation (OAT) provides satisfactory outcomes for osteochondral defects, for large defects OAT is often inadequate because of graft availability. Osteochondral allograft transplantation is an alternative treatment for large defects, but this approach is limited by graft storage constraints and carries disease transmission risks. Platelet-rich fibrin (PRF) is a second-generation platelet concentrate, and its positive effect on articular cartilage has been reported. However, the effect of PRF with OAT of osteochondral defects is unknown. Purpose: To compare the effects of OAT with platelet-rich plasma (PRP) and PRF on osteochondral defects in a rabbit model. Study Design: Controlled laboratory study. Methods: Forty-two juvenile rabbits were divided into control, PRP, and PRF groups. In the control and PRP groups, a cylindrical osteochondral defect (5 mm in diameter and 2 mm in depth) was created on the patellar groove, and an osteochondral graft (3.5 mm in diameter and 5 mm in length) harvested from the contralateral side was inserted into the distal portion of the defect. After wound closure, either normal saline or PRP was injected in the knee. In the PRF group, a PRF clot was placed in the defect before grafting. The surgical site was macroscopically and histologically assessed after 3 and 12 weeks. Results: At 3 weeks, the PRF group (n = 8) was macroscopically healed compared with the other 2 groups (control, n = 7; PRP, n = 6) (P < .005). Histologically, osteochondral graft cartilage of the PRF group had normal cellularity and higher amounts of safranin O staining relative to the other 2 groups (P < .005). At 12 weeks, all 3 groups (n = 8 per group) were macroscopically healed with normal or nearly normal cartilage, and osteochondral graft cartilage was histologically hyaline cartilage. In contrast, the PRF group healed with hyaline-like cartilage at nongrafted defects, whereas the other 2 groups healed with fibrocartilage (P < .001). Conclusion: OAT with PRF maintained hyaline cartilage, and the nongrafted defect healed with hyaline-like cartilage. Clinical Relevance: PRF has the potential to improve clinical outcomes of OAT used to treat osteochondral lesions. [ABSTRACT FROM AUTHOR]

Background: Matrix-associated autologous chondrocyte transplantation (MACT) has been an effective therapy for large, full-thickness cartilage lesions for years. However, little is known about how graft maturation is affected by characteristics of transplanted chondrocytes. Purpose: To investigate the influence of gene expression of chondrocytes at the time of transplantation on MRI outcomes up to 2 years after MACT. Study Design: Case series; Level of evidence, 4. Methods: This study included 25 patients with 27 symptomatic traumatic defects of articular cartilage, who had undergone MACT in the knee. Postoperative MRI examinations were conducted at 3, 6, 12, and 24 months after surgery. Biochemical graft maturation was assessed by measuring T2 relaxation time values of the transplant and healthy native cartilage areas. The MOCART (magnetic resonance observation of cartilage repair tissue) score was used to evaluate the morphological quality of regeneration tissue. Gene expression (collagen type I, collagen type II, aggrecan, versican, and interleukin-1β) was determined by real-time polymerase chain reaction (PCR) in transplant residuals at the time point of transplantation and was correlated with MRI outcomes using Spearman’s rank correlation coefficient. A Friedman test with post hoc analysis (Wilcoxon signed rank test) conducted with a Bonferroni correction was applied to compare scores at different time points. Results: T2 relaxation time of regeneration tissue improved from a mean ± SD of 74.6 ± 20.1 milliseconds at 3 months to 47.9 ±13.3 milliseconds at 24 months (P < .003). These values were similar to the T2 relaxation times of the native surrounding cartilage (50.9 ± 15 ms). The calculated T2 index (ratio of regeneration tissue to native cartilage) improved from 1.63 ± 0.76 at 3 months to 1.0 ± 0.4 at 24 months (P < .011). The MOCART score increased from 51.6 ± 15 points to 72.4 ± 12.2 points (P < .001). Improvement of the T2 index over time significantly correlated with aggrecan, COL1A1, COL2A1, and versican expression (rs = 0.9, P < .001; rs = 0.674, P < .012; rs = 0.553, P < .05; and rs = 0.575, P < .04, respectively). No correlation was found for IL-1β. Conclusion: These data demonstrate that matrix production in transplanted chondrocytes affects maturation of MACT grafts in MRI 2 years after surgery. [ABSTRACT FROM AUTHOR]

Background: Anterior cruciate ligament (ACL) injury is a well-known risk factor for the development of posttraumatic osteoarthritis (PTOA). However, whether using continuous passive motion (CPM) with or without additional treadmill exercise (TRE) in early ACL injury might provide chondroprotective effects and further decrease the risk of PTOA has yet to be determined. Hypothesis: CPM may offer an enhanced chondroprotective effect, but TRE may attenuate that effect due to the mechanical stress on the joint and inflammatory cytokines in the joint. Study Design: Controlled laboratory study. Methods: Thirty adult New Zealand White male rabbits were randomly allocated to sedentary (SED), CPM, TRE, or CPM+TRE groups. Each rabbit underwent an ACL transection (ACLT) on the right knee, with the contralateral knee used as an internal control (sham). The 4 joint surfaces (ie, medial and lateral femoral condyles and tibial plateaus) were evaluated 4 weeks after surgery for gross appearance, histological characteristics, and quantitative osteoarthritis (OA) scores. Results: Overall, at the end of testing, the CPM group experienced the best protective therapeutic effects in all compartments. In gross appearance, CPM resulted in normal articular surfaces, while the TRE and SED groups exhibited surface abrasion. Histological analysis showed significant differences in articular cartilage status. The CPM group had significantly better histological OA scores (P < .01), corresponding to the smoothest cartilage surface and sound chondrocyte and collagen arrangement. This group also showed abundant glycosaminoglycan (GAG) content and a sound growth microenvironment, with significantly lower expression levels of the inflammatory cytokine tumor necrosis factor α and the apoptotic marker caspase 3. In contrast, the TRE and SED groups showed several features of damage: distinct graded cartilage abrasion; damaged collagen fibers, corresponding to noticeable collagen type X (osteoarthritic cartilage); reduced cartilage thickness; fewer cartilaginous cells; and the appearance of chondrocyte clusters. These groups also showed loss of GAG, corresponding to higher levels of inflammatory cytokines and apoptosis of articular chondrocytes. Furthermore, the CPM+TRE group displayed visible pathological changes in the superficial cartilage, indicating that early loading exercise may contribute to osteoarthritis. The sham treatment showed no difference in the changes in all compartments between groups. Conclusion: Immediate CPM therapy produces a superior in situ microenvironment for reducing the occurrence of PTOA after ACL injury without reconstruction in rabbits. Clinical Relevance: These data suggest that immediate application of CPM therapy may be necessary to create a sound microenvironment in joints and possibly to decrease the risk of PTOA without or while awaiting ACL reconstruction. In contrast, both early active loading exercise and inactivity lead to the development of PTOA. [ABSTRACT FROM AUTHOR]

Background: The open modified Broström anatomic repair technique is widely accepted as the reference standard for lateral ankle stabilization. Despite recent increases in publications regarding arthroscopic repair of the anterior talofibular ligament (ATFL) for treatment of chronic ankle instability, research is lacking that compares the functional outcomes between arthroscopic repair and open repair procedures for chronic ankle instability. Purpose: To compare function and activity level after arthroscopic repair versus open repair of the ATFL in patients with lateral ankle instability. Study Design: Cohort study; Level of evidence, 3. Methods: All patients who underwent arthroscopic or open surgical Broström repair of the ATFL between January 2012 and August 2014 were invited to participate in this study. All of the patients had consented for arthroscopic repair if feasible. In cases in which arthroscopic repair was impossible, the open modified Broström procedure was performed after arthroscopy. Patients accepted a systematic rehabilitation program postoperatively. American Orthopaedic Foot and Ankle Society (AOFAS) score, Karlsson Ankle Functional Score (KAFS), and Tegner activity score were used to evaluate ankle function preoperatively and at a minimum follow-up of 2 years. Magnetic resonance imaging (MRI) was performed to evaluate the signal to noise ratio (SNR) of the repaired ATFL. Results: A total of 60 patients were included in this study. They were assigned to 1 of 2 groups according to their surgical procedure: 23 patients underwent arthroscopic repair (arthroscopic group) and 37 patients underwent open repair (open group). No patient in either group had ankle instability at follow-up postoperatively. After surgery, the AOFAS score (P < .001), KAFS (P < .001), and Tegner activity score (P < .001) increased significantly in both groups. However, no significant difference was found in AOFAS score (93.3 ± 8.9 vs 92.4 ± 8.6; P = .7), KAFS (90.3 ± 12.5 vs 89.4 ± 10.6; P = .75), and Tegner score (5 ± 2 vs 5 ± 2; P = .61) between the arthroscopic group and the open group, respectively. As well, no significant difference was found in the mean SNR value of ATFL between the arthroscopic group and the open group (9.1 ± 2.7 vs 8.8 ± 2.3; P = .39, respectively). Conclusion: When compared with open lateral ankle repair, arthroscopic repair of lateral ankle ligament when feasible produced similarly favorable outcomes. Arthroscopic ATFL repair, as a minimally invasive technique, provided favorable outcomes. [ABSTRACT FROM AUTHOR]

Background: Osteochondral allograft (OCA) transplantation is an integral part of the cartilage repair paradigm, but insufficient data are available regarding return to sport or recreational activity after the procedure. Purpose: The purpose of this study was to determine if athletic patients undergoing OCA transplantation returned to sport, assess reasons for not returning to sport, and ascertain patient and graft-related characteristics that differed between those who returned or did not return to sport. The secondary aims were to assess graft survivorship and patient-reported subjective outcome measures (pain, function, satisfaction) among athletic patients undergoing OCA transplantation. Study Design: Case series; Level of evidence, 4. Methods: We identified 149 knees in 142 patients who participated in sport or recreational activity before a cartilage injury (45% highly competitive athletes and 55% well-trained and frequently sporting) and underwent OCA transplantation in the knee. The mean age was 31.2 years and 58.4% were male. Information on preinjury and postoperative participation in sport or recreational activity was collected. Patients not returning to sport after OCA transplantation were mailed a questionnaire to assess why. Postoperative pain, function, and satisfaction scores were obtained, and further surgery on the operative knee was documented. Results: At a mean follow-up of 6 years, 75.2% of knees returned to sport or recreational activity. Among those who did not return to sport, knee-related issues and lifestyle changes were cited as reasons why. Patients who did not return to sport were more likely to be female, have injured their knee in an activity other than sport, and have a larger graft size. The diagnosis and anatomic location also differed. Overall, 71% of knees reported having “very good” to “excellent” function, and 79% were able to participate in a high level of activity (moderate, strenuous, or very strenuous) postoperatively. After OCA transplantation, 25.5% of knees underwent further surgery; 14 knees (9.4% of entire cohort) were considered allograft failures. Among the 135 knees that had the graft remaining in situ, pain and function improved from preoperatively to the latest follow-up on all measures, and 91% of patients were satisfied with the results of the surgery. Conclusion: OCA transplantation is a successful treatment option for athletes and highly active patients who sustain a cartilage injury to their knee. The majority of patients returned to sport or recreational activity. [ABSTRACT FROM AUTHOR]

Background: The treatment of symptomatic cartilage defects of the patella is particularly challenging, and no gold standard is currently available. Purpose: To evaluate the clinical results of a biphasic cell-free collagen-hydroxyapatite scaffold and to evaluate osteochondral tissue regeneration with magnetic resonance imaging (MRI). Study Design: Case series; Level of evidence, 4. Methods: Thirty-four patients (18 men and 16 women; mean ± SD: age, 30.0 ± 10 years) were treated by scaffold implantation for knee chondral or osteochondral lesions of the patella (area, 2.1 ± 1 cm2). The clinical evaluation was performed prospectively at 12 and 24 months via the IKDC (International Knee Documentation Committee; objective and subjective) and Tegner scores. MRI evaluation was performed at both follow-ups in 18 lesions through the MOCART score (magnetic resonance observation of cartilage repair tissue) and specific subchondral bone parameters. Results: A statistically significant improvement in all the scores was observed at 12- and 24-month follow-up as compared with the basal evaluation. The IKDC subjective score improved from 39.5 ± 14.5 to 61.9 ± 14.5 at 12 months (P > .0005) with a further increase to 67.6 ± 17.4 at 24 months of follow-up (12-24 months, P = .020). The MRI evaluation showed a stable value of the MOCART score between 12 and 24 months, with a complete filling of the cartilage in 87.0% of the lesions, complete integration of the graft in 95.7%, and intact repair tissue surface in 69.6% at final follow-up. The presence of osteophytes or more extensive bony overgrowth was documented in 47.8% of the patients of this series, but no correlation was found between MRI findings and clinical outcome. Conclusion: The implantation of a cell-free collagen-hydroxyapatite osteochondral scaffold provided a clinical improvement at short-term follow-up for the treatment of patellar cartilage defects. Women had lower outcomes, and the need for realignment procedures led to a slower recovery. MRI evaluation showed some abnormal findings with the presence of bone overgrowth, but no correlation has been found with the clinical outcome. [ABSTRACT FROM AUTHOR]

Background: Second anterior cruciate ligament (ACL) tears after reconstruction occur at a reported rate of 20% to 30%. This high frequency indicates that there may be factors that predispose an athlete to graft failure and ACL tears of the contralateral knee. Purpose: To determine the incidence of second ACL injuries in a geographic population-based cohort over a 10-year observation period. Study Design: Descriptive epidemiological study. Methods: International Classification of Diseases, 9th Revision (ICD-9) codes relevant to the diagnosis of an ACL tear and the procedure code for ACL reconstruction were searched across the Rochester Epidemiology Project, a multidisciplinary county database, between the years of 1990 and 2000. This cohort of patients was tracked for subsequent ACL injuries through December 31, 2015. The authors identified 1041 patients with acute, isolated ACL tears. These patients were stratified by primary and secondary tears, sex, age, activity level, side of injury, sex by side of injury, and graft type. Results: Of the 1041 unique patients with a diagnosed ACL tear in Olmsted County, Minnesota, from 1990 to 2000, there were 66 (6.0%) second ACL tears; 66.7% of these tears occurred on the contralateral side. A second ACL injury was influenced by graft type (P < .0001), election of ACL reconstruction (P = .0060), and sex by side of injury (P = .0072). Nonparametric analysis of graft disruption by graft type demonstrated a higher prevalence of second ACL tears with allografts compared with hamstring (P = .0499) or patellar tendon autografts (P = .0012). Conclusion: The incidence of second ACL tears in this population-based cohort was 6.0%, with 66.7% of these tears occurring on the contralateral side from the original injury. There was a high population incidence of second ACL injuries in female patients younger than age 20 years. The utilization of patellar tendon autografts significantly reduced the risk of second ACL injuries compared with allografts or hamstring autografts in this cohort. [ABSTRACT FROM AUTHOR]

Background: Recommendations exist to encourage safe youth participation in sport. These recommendations include not specializing in 1 sport, limiting participation to less than 8 months per year, and limiting participation to fewer hours per week than a child’s age. However, limited evidence exists to support or refute these recommendations. Hypothesis: High levels of specialization will be associated with a history of injuries and especially overuse injuries, independent of age, sex, or weekly sport training hours. Athletes who exceed current sport volume recommendations will be more likely to have a history of injuries and overuse injuries. Study Design: Case-control study; Level of evidence, 3. Methods: Youth athletes (n = 2011; 989 female and 1022 male; 12-18 years of age) completed a questionnaire regarding their specialization status, yearly and weekly sport participation volume, and injury history. Specialization was classified as low, moderate, or high using a previously utilized 3-point scale. Athletes were classified into groups based on either meeting or exceeding current volume recommendations (months per year and hours per week). Odds ratios (ORs) and 95% CIs were calculated to investigate associations of specialization and volume of participation with a history of sport-related injuries in the past year (P ≤ .05). Results: Highly specialized athletes were more likely to report a previous injury of any kind (P < .001; OR, 1.59; 95% CI, 1.26-2.02) or an overuse injury (P = .011; OR, 1.45; 95% CI, 1.07-1.99) in the previous year compared with athletes in the low specialization group. Athletes who played their primary sport more than 8 months of the year were more likely to report an upper extremity overuse injury (P = .04; OR, 1.68; 95% CI, 1.06-2.80) or a lower extremity overuse injury (P = .001; OR, 1.66; 95% CI, 1.22-2.30). Athletes who participated in their primary sport for more hours per week than their age (ie, a 16-year-old athlete who participated in his or her primary sport for more than 16 h/wk) were more likely to report an injury of any type (P = .001; OR, 1.34; 95% CI, 1.12-1.61) in the previous year. Conclusion: High levels of specialization were associated with a history of injuries, independent of age, sex, and weekly organized sport volume. Athletes who exceeded volume recommendations were more likely to have a history of overuse injuries. Clinical Relevance: Parents and youth athletes should be aware of the risks of specialization and excessive sport volume to maximize safe sport participation. [ABSTRACT FROM AUTHOR]

Background: The number of arthroscopic rotator cuff surgeries is consistently increasing. Although generally considered successful, the reported number of retears after rotator cuff repair is substantial. Short-term clinical outcomes are reported to be rarely impaired by tendon retears, whereas to our knowledge, there is no study documenting long-term clinical outcomes and tendon integrity after arthroscopic rotator cuff repair. Purpose: To investigate longitudinal long-term repair integrity and clinical outcomes after arthroscopic rotator cuff reconstruction. Study Design: Case series; Level of evidence, 4. Methods: Thirty patients who underwent arthroscopic rotator cuff repair with suture anchors for a full-tendon full-thickness tear of the supraspinatus or a partial-tendon full-thickness tear of the infraspinatus were included. Two and 10 years after initial arthroscopic surgery, tendon integrity was analyzed using magnetic resonance imaging (MRI). The University of California, Los Angeles (UCLA) score and Constant score as well as subjective questions regarding satisfaction with the procedure and return to normal activity were used to evaluate short- and long-term outcomes. Results: At the early MRI follow-up, 42% of patients showed a full-thickness rerupture, while 25% had a partial rerupture, and 33% of tendons remained intact. The 10-year MRI follow-up (129 ± 11 months) showed 50% with a total rerupture, while the other half of the tendons were partially reruptured (25%) or intact (25%). The UCLA and Constant scores significantly improved from preoperatively (UCLA total: 50.6% ± 20.2%; Constant total: 44.7 ± 10.5 points) to 2 years (UCLA total: 91.4% ± 16.0% [P < .001]; Constant total: 87.8 ± 15.3 points [P < .001]) and remained significantly higher after 10 years (UCLA total: 89.7% ± 15.9% [P < .001]; Constant total: 77.5 ± 15.6 points [P < .001]). The Constant total score and Constant strength subscore, but not the UCLA score, were also significantly better at 10 years postoperatively in patients with intact tendons compared with patients with retorn tendons (Constant total: 89.0 ± 7.8 points vs 75.7 ± 14.1 points, respectively [P = .034]; Constant strength: 18.0 ± 4.9 points vs 9.2 ± 5.2 points, respectively [P = .006]). The majority of patients rated their satisfaction with the procedure as “excellent” (83.3%), and 87.5% returned to their normal daily activities. Conclusion: Arthroscopic rotator cuff repair showed good clinical long-term results despite a high rate of retears. Nonetheless, intact tendons provided significantly superior clinical long-term outcomes, making the improvement of tendon healing and repair integrity important goals of future research efforts. [ABSTRACT FROM AUTHOR]

Background: Although survival of transplanted stem cells in vivo and differentiation of stem cells into tenocytes in vitro have been reported, there have been no in vivo studies demonstrating that mesenchymal stem cells (MSCs) could secrete their own proteins as differentiated tenogenic cells. Purpose/Hypothesis: Using a xenogeneic MSC transplantation model, we aimed to investigate whether MSCs could differentiate into the tenogenic lineage and secrete their own proteins. The hypothesis was that human MSCs would differentiate into the human tenogenic lineage and the cells would be able to secrete human-specific proteins in a rat tendon injury model. Study Design: Controlled laboratory study. Methods: The Achilles tendons of 57 Sprague Dawley rats received full-thickness rectangular defects. After the modeling, the defective tendons were randomly assigned to 3 groups: (1) cell group, implantation with human adipose-derived mesenchymal stem cells (hASCs) and fibrin glue (106 cells in 60 μL); (2) fibrin group, implantation with fibrin glue and same volume of cell media; and (3) sham group, identical surgical procedure without any treatment. Gross observation and biomechanical, histopathological, immunohistochemistry, and Western blot analyses were performed at 2 and 4 weeks after modeling. Results: hASCs implanted into the defective rat tendons were viable for 4 weeks as detected by immunofluorescence staining. Tendons treated with hASCs showed better gross morphological and biomechanical recovery than those in the fibrin and sham groups. Furthermore, the expression of both human-specific collagen type I and tenascin-C was significantly higher in the cell group than in the other 2 groups. Conclusion: Transplantation of hASCs enhanced rat tendon healing biomechanically. hASCs implanted into the rat tendon defect model survived for at least 4 weeks and secreted human-specific collagen type I and tenascin-C. These findings suggest that transplanted MSCs may be able to differentiate into the tenogenic lineage and contribute their own proteins to tendon healing. Clinical Relevance: In tendon injury, MSCs can enhance tendon healing by secreting their own protein and have potential as a therapeutic option in human tendinopathy. [ABSTRACT FROM AUTHOR]

Background: The windmill pitching motion has been associated with risk for shoulder injury. Because there are no pitching limits on youth fast-pitch softball pitchers, these athletes often pitch multiple games across consecutive days. Strength changes, fatigue levels, and shoulder pain that develop among female fast-pitch pitchers over the course of consecutive days of pitching have not been investigated. Hypothesis: Over the course of 2- and 3-day fast-pitch softball tournaments, pitchers will develop progressive objective weakness and increased subjective shoulder fatigue and pain without complete recovery between days. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Fourteen female fast-pitch softball pitchers between the ages of 14 and 18 years were evaluated for strength and fatigue changes across 2- and 3-day tournaments. At the beginning and end of each day of tournament play, pitchers were asked to quantify shoulder fatigue and shoulder pain levels of their dominant throwing arm using a 10-point visual analog scale (VAS). Shoulder abduction, flexion, external rotation, internal rotation, elbow flexion, and elbow extension strength measurements were gathered using a handheld dynamometer. Results: Over the course of an average single day of tournament participation, pitchers developed significant increases in VAS scores for shoulder fatigue (median, 2.0; 95% CI, 1.3-3.0) and pain (median, 1.3; 95% CI, 0.5-2.3) and significant strength loss in all tested motions. Pitchers also developed significant increases in VAS shoulder fatigue (median, 3.5; 95% CI, 1.5-5.5), VAS shoulder pain (median, 2.5; 95% CI, 1.0-4.5), and strength loss in all tested motions over the entire tournament. Shoulder pain, fatigue, and strength do not fully recover between days. The accumulation of subjective shoulder pain and fatigue over the course of tournament play were closely correlated. Conclusion: Among youth female fast-pitch softball pitchers, there is a progressive increase in shoulder fatigue, pain, and weakness over the course of 2- and 3-day tournaments without full recovery between consecutive days of pitching. [ABSTRACT FROM AUTHOR]

Background: With their unremittingly high incidence rate and detrimental functional repercussions, hamstring injuries remain a substantial problem in male soccer. Proximal neuromuscular control (“core stability”) is considered to be of key importance in primary and secondary hamstring injury prevention, although scientific evidence and insights on the exact nature of the core-hamstring association are nonexistent at present. Hypothesis: The muscle activation pattern throughout the running cycle would not differ between participants based on injury occurrence during follow-up. Study Design: Case-control study; Level of evidence, 3. Methods: Sixty amateur soccer players participated in a multimuscle surface electromyography (sEMG) assessment during maximal acceleration to full-speed sprinting. Subsequently, hamstring injury occurrence was registered during a 1.5-season follow-up period. Hamstring, gluteal, and trunk muscle activity time series during the airborne and stance phases of acceleration were evaluated and statistically explored for a possible causal association with injury occurrence and absence from sport during follow-up. Results: Players who did not experience a hamstring injury during follow-up had significantly higher amounts of gluteal muscle activity during the front swing phase (P = .027) and higher amounts of trunk muscle activity during the backswing phase of sprinting (P = .042). In particular, the risk of sustaining a hamstring injury during follow-up lowered by 20% and 6%, with a 10% increment in normalized muscle activity of the gluteus maximus during the front swing and the trunk muscles during the backswing, respectively (P < .024). Conclusion: Muscle activity of the core unit during explosive running appeared to be associated with hamstring injury occurrence in male soccer players. Higher amounts of gluteal and trunk muscle activity during the airborne phases of sprinting were associated with a lower risk of hamstring injuries during follow-up. Hence, the present results provide a basis for improved, evidence-based rehabilitation and prevention, particularly focusing on increasing neuromuscular control of the gluteal and trunk muscles during sport-specific activities (eg, sprint drills, agility drills). [ABSTRACT FROM AUTHOR]

Background: Research in sport concussion has increased greatly over the previous decade due to increased scientific interest as well as the media and political spotlight that has been cast on this injury. However, a dearth of literature is available regarding the long-term (>1 year after concussion) effects of adolescent concussion on cognitive and motor performance of high school athletes. Purpose: To evaluate the potential for long-term effects of concussion sustained during high school on cognitive and motor performance across the lifespan. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Adults with (n = 30) and without (n = 53) a concussion history were recruited in 3 age groups: younger (18-30 years; n = 43), middle-aged (40-50 years; n = 18), and older (≥60 years; n = 22). Each participant completed a computerized neurocognitive assessment and continuous tracking and discrete temporal auditory tasks with the hand and foot. Root mean squared error and timing variability were derived from the tracking and temporal auditory tasks, respectively. Data were analyzed by regression analyses for each recorded variable. Results: The analysis revealed significant age effects on neurocognitive task, continuous tracking task, and discrete auditory timing task performance (P values < .05). No concussion history or interaction (concussion history by age) effects were found for performance on any task (P values > .05). Conclusion: While longitudinal investigations are still needed, this cross-sectional study failed to identify any observable effect of adolescent concussion history on cognition or motor performance with age. [ABSTRACT FROM AUTHOR]

Background: Deficits in plantarflexor function are common after an Achilles tendon rupture. These deficits may result in an altered distribution of joint loads during lower extremity tasks. Hypothesis: We hypothesized that, regardless of treatment, the Achilles tendon-ruptured limb would exhibit deficits in ankle kinematics and joint power while exhibiting elevated knee joint power and patellofemoral joint loads during walking, jogging, and hopping. We further hypothesized that this loading pattern would be most evident during jogging and hopping. Study Design: Controlled laboratory study. Methods: Thirty-four participants (17 participants treated surgically, 17 treated nonsurgically) were tested at a mean 6.1 ± 2.0 years after an Achilles tendon rupture. Lower extremity kinematics and kinetics were assessed while participants completed walking, jogging, and single-legged hopping trials. Patellofemoral joint stress was calculated via a musculoskeletal model. Data were analyzed via mixed-model repeated analyses of variance (α = .05) and the limb symmetry index (LSI). Results: No differences (P ≥ .05) were found between the surgical and nonsurgical groups. In both groups, large side-to-side deficits in the plantarflexion angle at toeoff (LSI: 53.5%-73.9%) were noted during walking, jogging, and hopping in the involved limb. Side-to-side deficits in the angular velocity were only present during jogging (LSI: 93.5%) and hopping (LSI: 92.5%). This pattern was accompanied by large deficits in eccentric (LSI: 80.8%-94.7%) and concentric (LSI: 82.2%-84.7%) ankle joint powers in the involved limb during all tasks. Interestingly, only jogging and hopping demonstrated greater knee joint loads when compared with the uninvolved limb. Concentric knee power was greater during jogging (LSI: 117.2%) and hopping (LSI: 115.9%) compared with the uninvolved limb. Similarly, peak patellofemoral joint stress was greater in the involved limb during jogging (LSI: 107.5%) and hopping (LSI: 107.1%), while only hopping had a greater loading rate of patellofemoral joint stress (LSI: 110.9%). Conclusion: Considerable side-to-side deficits in plantarflexor function were observed during walking, jogging, and hopping in patients after an Achilles tendon rupture. As a possible compensation, increased knee joint loads were present but only during jogging and hopping. Clinical Relevance: These data suggest that after an Achilles tendon rupture, patients may be susceptible to greater mechanical loading of the knee during sporting tasks, regardless of surgical or nonsurgical treatment. [ABSTRACT FROM AUTHOR]

Background: Few studies have investigated detailed 3-dimensional lower extremity kinematics during baseball pitching in adolescent athletes during extended play. Changes in these parameters may affect performance outcomes. Purpose: To investigate whether adolescent baseball pitchers experience changes in lower extremity kinematics and event timing during a simulated game-length pitching bout. Study Design: Descriptive laboratory study. Methods: Twelve male adolescent pitchers (aged 14-16 years) threw 6 sets of 15 fastball pitches from an artificial pitching mound to a target at regulation distance. Joint angles and angular velocities at the hip, knee, and ankle of both legs were collected throughout the phases of the pitching cycle as well as stride length, pelvis orientation, pitch duration, timing of foot contact and ball release, ball speed, and pitching accuracy. Paired t tests (P < .05) were used to compare the dependent variables between the last 5 pitches of the second (baseline) and sixth (final) sets. Results: During the stride phase, decreased maximum angular excursions for hip extension (baseline: 14.7° ± 9.8°; final: 11.6° ± 10.3°; P < .05) and ankle plantar flexion (baseline: 30.2° ± 14.5°; final: 24.2° ± 15.3°; P < .05) as well as maximum angular velocity for knee extension (baseline: 144.9 ± 63.3 deg·s-1; final: 121.7 ± 62.0 deg·s-1; P < .05) were observed between sets in the trailing leg. At foot contact, pitchers had decreased hip flexion (baseline: 69.5° ± 10.1°; final: 66.5° ± 11.8°; P < .05) and increased hip abduction (baseline: 20.7° ± 8.9°; final: 25.4° ± 6.0°; P < .05) in the leading leg in the final set. Compared with the baseline set, ball speed significantly decreased in the final set (29.5 ± 2.5 m·s-1 vs 28.3 ± 2.5 m·s-1, respectively; P < .05). Conclusion: Kinematic changes and decreased ball speeds observed in the final set suggest that adolescent pitchers are unable to maintain lower extremity kinematics and performance as a result of extended play. Clinical Relevance: The results from this study may warrant further investigation into how altered lower extremity kinematics may affect trunk and upper extremity function, performance, and risk of injuries during pitching in adolescent athletes, particularly during actual game play. [ABSTRACT FROM AUTHOR]

Background: Noncontact anterior cruciate ligament (ACL) injury after valgus landing has been reported and studied biomechanically. However, the role of the medial collateral ligament (MCL) in dissipating these forces has not been fully elucidated. Purpose/Hypothesis: The purpose of this study was to investigate the role that the MCL plays in ACL strain during simulated landing. The hypothesis was that ACL strain would increase significantly in MCL-incompetent knees compared with the native knee and that reconstructing the MCL would return the values to those of the intact knee. Study Design: Controlled laboratory study. Methods: Eight fresh-frozen human cadaveric knees were used in this study. A materials testing machine applied a force of 2× body weight over 60 milliseconds to simulate landing after a jump. The knees were tested in 12 loading conditions, consisting of full extension or 15° of flexion combined with 7° of valgus or neutral alignment while the tibia was in external rotation, neutral rotation, or internal rotation. This test procedure was repeated on each specimen with the MCL transected and reconstructed. The superficial and deep MCL was transected along with the posterior oblique ligament, which was thought to simulate a worst case scenario. The MCL was reconstructed by use of semitendinosus and gracilis tendon grafts. Results: During internal rotation at 0° of flexion and 0° of valgus, both the intact (P = .005) and the reconstructed (P = .004) MCL states placed significantly lower strain on the ACL than did the transected MCL. The reconstructed MCL state at 0° of flexion and 7° of valgus (P = .049) along with 15° of flexion and 0° of valgus (P = .020) also placed significantly lower strain on the ACL than did the transected MCL. For external rotation testing at 0° of flexion and 7° of valgus, the reconstructed MCL state placed significantly lower strain on the ACL than did the transected MCL (P = .039). Finally, during neutral rotation, the ACL strain at 0° of valgus and 0° of flexion, and at 7° of valgus and 0° of flexion was significantly lower for the MCL-intact groups (P < .028) and MCL-reconstructed groups (P < .016) than the MCL-transected groups. Conclusion: The current findings demonstrate that during valgus landing, a knee with an incompetent MCL puts the ACL under increased strain. These values are highest in full extension with the tibia in internal and neutral rotation. This increased strain can be reduced to baseline levels with reconstruction. Clinical Relevance: A knee with an incompetent MCL puts the ACL under increased strain. Once the MCL has healed in an elongated manner, MCL reconstruction should be considered. [ABSTRACT FROM AUTHOR]

Background: Mesenchymal stem cells (MSCs) are promising candidates as a cell-based therapy for osteoarthritis (OA), although current results are modest. Pre-treatment of MSCs before application might improve their therapeutic efficacy. Hypothesis: Pre-treatment of MSCs with inflammatory factors or hypoxia will improve their migration and adhesion capacities toward OA-affected tissues. Study Design: Controlled laboratory study. Methods: We used real-time polymerase chain reaction to determine the effects of different fetal calf serum (FCS) batches, platelet lysate (PL), hypoxia, inflammatory factors, factors secreted by OA tissues, and OA synovial fluid (SF) on the expression of 12 genes encoding chemokine or adhesion receptors. Migration of MSCs toward factors secreted by OA tissues was studied in vitro, and attachment of injected MSCs was evaluated in vivo in healthy and OA knees of male Wistar rats. Results: Different FCS batches, PL, or hypoxia did not influence the expression of the migration and adhesion receptor genes. Exposure to inflammatory factors altered the expression of CCR1, CCR4, CD44, PDGFRα, and PDGFRβ. MSCs migrated toward factors secreted by OA tissues in vitro. Neither pre-treatment with inflammatory factors nor the presence of OA influenced MSC migration in vitro or adhesion in vivo. Conclusion: Factors secreted by OA tissues increase MSC migration in vitro. In vivo, no difference in MSC adhesion was found between OA and healthy knees. Pre-treatment with inflammatory factors influenced the expression of migration and adhesion receptors of MSCs but not their migration in vitro or adhesion in vivo.Clinical Relevance:To improve the therapeutic capacity of intra-articular injection of MSCs, they need to remain intra-articular for a longer period of time. Pre-treatment of MSCs with hypoxia or inflammatory factors did not increase the migration or adhesion capacity of MSCs and will therefore not likely prolong their intra-articular longevity. Alternative approaches to prolong the intra-articular presence of MSCs should be developed to increase the therapeutic effect of MSCs in OA. [ABSTRACT FROM AUTHOR]

Background: A corticosteroid injection is commonly used to treat tendinopathy, but it has been associated with negative effects on tendon homeostasis. Platelet-rich plasma (PRP) is known to have proliferative and anabolic effects as well as cytoprotective effects against corticosteroids on tenocytes. However, the combined effects of a corticosteroid and PRP on the anti-inflammatory, matrix synthesis, and cytoprotective potential of tenocytes in conditions simulating tendinopathy have not been investigated. Purpose: To assess the effects of PRP on tenocytes from degenerative rotator cuff tears with the concomitant use of a corticosteroid in interleukin 1β (IL-1β)-induced tendinopathic conditions.Study Design: Controlled laboratory study. Methods: Tenocytes were enzymatically isolated and cultured from patients with degenerative rotator cuff tears. PRP was prepared using a plateletpheresis system, and growth factor concentrations were measured. To evaluate the gene expression of proinflammatory and anti-inflammatory cytokines, enzymes and their inhibitors, and matrix molecules, cells were cultured with 1 ng/mL IL-1β, 1 μM dexamethasone, and 10% (vol/vol) platelet-poor plasma (PPP) and PRP of 200, 1000, and 4000 × 10³/μL; quantitative real-time reverse transcriptase polymerase chain reaction was also performed. Western blotting was performed to investigate the protein synthesis of degradative enzymes and their inhibitors. Cell viability, apoptosis, and senescence assays were also conducted. Results: PRP did not interfere with the anti-inflammatory effects of dexamethasone on tenocytes pretreated with IL-1β, but it increased the synthesis of tissue inhibitor of metalloproteinase (TIMP)-1 and -3. Meanwhile, PRP did not induce anti-inflammatory cytokines that had been suppressed with a corticosteroid. It did increase the type I/III collagen ratio mainly through the suppression of type III collagen expression. PRP reversed the decreased viability, increased apoptosis, and induced senescence with IL-1β and a corticosteroid. Conclusion: This study shows that the addition of PRP does not interfere with the anti-inflammatory effects of a corticosteroid on IL-1β-treated tenocytes from degenerative rotator cuff tears but that it does avoid the deleterious side effects of a corticosteroid. Clinical Relevance: PRP can be clinically useful with a corticosteroid as a treatment for tendinopathy. [ABSTRACT FROM AUTHOR]

Background: The use of autologous chondrocyte implantation (ACI) remains limited, even though multiple studies have demonstrated success rates exceeding 75%. The procedure is perceived as invasive and technically challenging, presenting barriers to more widespread adoption. Purpose/Hypothesis: The objective of this study was to investigate whether outcomes and the failure rate of a simplified ACI technique (cs-ACI) were comparable with those of the more complicated traditional technique of a chondrocyte suspension injected under a collagen membrane (cACI). We hypothesized that the change in technique would not negatively affect outcomes. Study Design: Cohort study; Level of evidence, 3. Methods: Thirty-nine patients treated with the cs-ACI technique fulfilled the inclusion requirements. A group of 45 patients treated previously with standard cACI was used as a comparison. The functional outcomes were prospectively collected both preoperatively and postoperatively at the last follow-up. Failure was defined as any graft removal of more than 25% of the original defect size. Magnetic resonance imaging was performed postoperatively, and scans were assessed using a modified MOCART (magnetic resonance observation of cartilage repair tissue) scoring system. Results: Group demographics were not significantly different, except for the defect size and mean follow-up: 4.09 years in the cACI group and 2.46 years in the cs-ACI group. Significant improvements were seen in all outcome measures except the Tegner score from the preoperative baseline to the latest follow-up for both the cACI group (International Knee Documentation Committee [IKDC] score, from 42.0 to 63.4; Knee injury and Osteoarthritis Outcome Score [KOOS]-Pain subscore, from 58.7 to 77.1; Lysholm score, from 57.2 to 69.7; and Tegner score, from 3.5 to 4.2) and the cs-ACI group (IKDC score, from 45.6 to 68.0; KOOS-Pain subscore, from 66.6 to 84.7; Lysholm score, from 53.7 to 75.4; and Tegner score, from 3.2 to 3.8). No significant difference was found between the groups at the latest follow-up. The failure rate at 2 years was not significantly different, while the total failure rate over the entire study period was significantly lower in the cs-ACI group than the cACI group (5% vs 24%, respectively). The overall MOCART score was not significantly different between the groups. Conclusion: The treatment of full-thickness articular cartilage defects with a simplified cell-seeded ACI technique demonstrated no significant differences in the failure rate and patient-reported outcomes when compared with a standard technique utilizing interrupted sutures and the injection of a cell suspension under a collagen membrane. [ABSTRACT FROM AUTHOR]

Background: The variability in outcomes after anterior cruciate ligament reconstruction (ACLR) might be related to the criteria that are used to determine athletes' readiness to return to their preinjury activity level. A battery of return-to-activity criteria (RTAC) that emphasize normal knee function and movement symmetry has been instituted to quantitatively determine athletes' readiness to return to preinjury activities. Purpose: To investigate performance-based and patient-reported measures at 12 and 24 months after ACLR between patients who passed or failed RTAC at 6 months after ACLR. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 108 patients who had participated in International Knee Documentation Committee level 1 or 2 sports activities completed RTAC testing at 6, 12, and 24 months after surgery. The RTAC included the isometric quadriceps strength index (QI), 4 single-legged hop tests, the Knee Outcome Survey-activities of daily living subscale (KOS-ADLS), and the global rating scale of perceived function (GRS). Patients who scored ≥90% on all RTAC were classified as the pass group, and those who scored <90% on any RTAC were classified as the fail group. At 12- and 24-month follow-ups, patients were asked if they had returned to the same preinjury activity level. Results: At the 6-month follow-up, there were 48 patients in the pass group and 47 in the fail group. At the 12-month follow-up, 31 patients (73.8%) from the pass group and 15 patients (39.5%) from the fail group passed RTAC, and at the 24-month follow-up, 25 patients (75.8%) from the pass group and 14 patients (51.9%) from the fail group passed RTAC. The rate of return to activities in the pass group was 81% and 84% at 12 and 24 months after ACLR, respectively, compared with only 44% and 46% in the fail group (P ≤ .012), respectively; however, some patients in the fail group participated in preinjury activities without being cleared by their therapists. At 12 and 24 months, 60.5% and 48.1% of patients continued to fail again on the criteria, respectively. A statistically significant group × time interaction was found for the single hop and 6-m timed hop limb symmetry indices (LSIs) (P ≤ .037), with only the fail group demonstrating a significant improvement over time. A main effect of group was detected for the QI and the crossover hop and triple hop LSIs (P < .01), with patients in the pass group demonstrating higher performance. A main effect of time was detected for the crossover hop and triple hop LSIs and the GRS, with improvements seen in both groups (P < .05). Conclusion: Patients who passed the RTAC early after ACLR were more likely to demonstrate normal knee function and movement symmetry at 12 and 24 months postoperatively, while patients who failed the RTAC early were more likely to demonstrate impaired knee function and movement asymmetry at 12- and 24-month follow-ups. Patients in the pass group had a higher rate of return to their preinjury activity level compared with those in the fail group. A group of patients chose to return to their preinjury activities, even though they were functionally not ready. [ABSTRACT FROM AUTHOR]

Background: Patellofemoral pain (PFP) is a prevalent disorder among female adolescents. Overuse is frequently cited as the cause of pain for this population. What is currently unclear, however, is if the patella demonstrates abnormal tracking patterns relative to the femoral trochlear groove in female adolescents with PFP. Purpose: The aim of this case-control study was to determine if abnormal patellar tracking patterns are present in female adolescents with PFP. The secondary aim was to identify if an increased tibial tuberosity-trochlear groove (TT-TG) distance is associated with the observed kinematic patterns. Study Design: Controlled laboratory study. Methods: Twenty female adolescent knees from 12 patients with PFP and 20 age-matched female knees from 13 healthy controls were recruited for this study. Patellofemoral kinematics (eg, lateral patellar displacement) during a repetitive knee extension-flexion maneuver was quantified by dynamic cine phase-contrast magnetic resonance imaging (MRI). Static MRI scans were used to determine the TT-TG distance. Results: Relative to the control cohort, female adolescents with PFP demonstrated significantly greater lateral displacement at 10° (3.2 mm; P < .001), 20° (2.3 mm; P < .001), and 30° (1.7 mm; P = .014) of knee flexion. A subgroup within this cohort (7 knees from 5 patients) demonstrated extreme lateral maltracking >2 SDs of the mean of the control cohort. This subgroup also demonstrated a greater TT-TG distance relative to the controls (Δ = 4.2 mm; P = .001). Conclusion: This study demonstrates abnormal lateral patellar displacement in the absence of patellar tilt in female adolescents with PFP. Because all adolescents from both cohorts participated in impact sports, it appears that rigorous athletic training alone is inadequate to produce symptoms in this population. Rather, PFP may derive from a combination of physical activity in the context of pathological kinematics. Clinical Relevance: Abnormal patellar tracking patterns and abnormal static alignment have been shown to contribute to the etiology of patellofemoral pain in adults. This study demonstrates that pathologic patellar tracking patterns are present in adolescent females with patellofemoral pain. [ABSTRACT FROM AUTHOR]

Background: Quantitative magnetic resonance (qMR) can be used to measure macromolecules in tissues and is a potential method of observing early cartilage changes in the development of posttraumatic osteoarthritis. Hypothesis/Purpose: We hypothesized that specific patient and surgical factors affecting cartilage matrix composition after anterior cruciate ligament (ACL) reconstruction (ACLR) can be detected using T1&#961 and T2 relaxation times. Our purpose was to demonstrate this ability in a multicenter feasibility study. Study Design: Case series; Level of evidence, 4. Methods: A total of 54 patients who underwent ACLR underwent bilateral MRI at baseline before surgery and 6 months postoperatively. Operative findings were recorded. T1&#961 and T2 relaxation times were calculated for 6 cartilage regions: the medial femur, lateral femur, medial tibia, lateral tibia, patella, and trochlea. A paired t test compared relaxation times at baseline and 6 months, univariate regression identified regions that influenced patient-reported outcome measures, and analysis of covariance was used to determine the surgical factors that resulted in elevated relaxation times at 6 months. Results: The injured knee had significantly prolonged T1&#961 and T2 relaxation times in the tibiofemoral compartment at baseline and 6 months but had shorter values in the patellofemoral compartment compared with the uninjured knee. Prolonged T1&#961 and T2 times at 6 months were noted for both the injured and uninjured knees. At 6 months, prolongation of T1&#961 and T2 times in the tibial region was associated with lower patient-reported outcome measures. ACLR performed within 30 days of injury had significantly shorter T1&#961 times in the tibial regions, and lateral meniscal tears treated with repair had significantly shorter T1&#961 times than those treated with excision. Conclusion: Prolonged relaxation times in multiple regions demonstrate how the injury affects the entire joint after an ACL tear. Changes observed in the uninjured knee may be caused by increased loading during rehabilitation, especially in the patellofemoral articular cartilage and distal femur. Relaxation times in the tibial regions may be predictive of patient symptoms at 6 months. These same regions are affected by surgical timing as early as 30 days after injury, but this may partially be reflective of the severity of the preoperative injury and the choice of treatment of meniscal tears. [ABSTRACT FROM AUTHOR]