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Background: Although graft choice may be limited in the revision setting based on previously used grafts, most surgeons believe that graft choice for anterior cruciate ligament (ACL) reconstruction is an important factor related to outcome. Hypothesis: In the ACL revision setting, there would be no difference between autograft and allograft in rerupture rate and patient-reported outcomes (PROs) at 6-year follow-up. Study Design: Cohort study; Level of evidence, 2. Methods: Patients who had revision surgery were identified and prospectively enrolled in this cohort study by 83 surgeons over 52 sites. Data collected included baseline characteristics, surgical technique and pathology, and a series of validated PRO measures. Patients were followed up at 6 years and asked to complete the identical set of PRO instruments. Incidence of additional surgery and reoperation because of graft failure were also recorded. Multivariable regression models were used to determine the predictors (risk factors) of PROs, graft rerupture, and reoperation at 6 years after revision surgery. Results: A total of 1234 patients including 716 (58%) men were enrolled. A total of 325 (26%) underwent revision using a bone-patellar tendon-bone (BTB) autograft; 251 (20%), soft tissue autograft; 289 (23%), BTB allograft; 302 (25%), soft tissue allograft; and 67 (5%), other graft. Questionnaires and telephone follow-up for subsequent surgery information were obtained for 809 (66%) patients, while telephone follow-up was only obtained for an additional 128 patients for the total follow-up on 949 (77%) patients. Graft choice was a significant predictor of 6-year Marx Activity Rating Scale scores ( P = .024). Specifically, patients who received a BTB autograft for revision reconstruction had higher activity levels than did patients who received a BTB allograft (odds ratio [OR], 1.92; 95% CI, 1.25-2.94). Graft rerupture was reported in 5.8% (55/949) of patients by their 6-year follow-up: 3.5% (16/455) of patients with autografts and 8.4% (37/441) of patients with allografts. Use of a BTB autograft for revision resulted in patients being 4.2 times less likely to sustain a subsequent graft rupture than if a BTB allograft were utilized ( P = .011; 95% CI, 1.56-11.27). No significant differences were found in graft rerupture rates between BTB autograft and soft tissue autografts ( P = .87) or between BTB autografts and soft tissue allografts ( P = .36). Use of an autograft was found to be a significant predictor of having fewer reoperations within 6 years compared with using an allograft ( P = .010; OR, 0.56; 95% CI, 0.36-0.87). Conclusion: BTB and soft tissue autografts had a decreased risk in graft rerupture compared with BTB allografts. BTB autografts were associated with higher activity level than were BTB allografts at 6 years after revision reconstruction. Surgeons and patients should consider this information when choosing a graft for revision ACL reconstruction.

Importance There have been numerous publications involving the use of biologics in sports medicine injuries. However, a lack of clarity exists with reporting industry affiliations and sources of funding. Objective The purposes of this study were (1) to determine the frequency of reporting of funding sources in randomised clinical trials evaluating the clinical effects of biological treatments in sports medicine and (2) to evaluate potential relationships between reported clinical results and affiliated funding sources. We hypothesised that funding sources would be under-reported and the favourability of the results would be associated with the specific type of funding received. Evidence review A systematic search of MEDLINE and Embase databases was performed to identify funding sources and favourability of conclusions reported for all randomised clinical trials that compared a biological treatment to a standard treatment for sports medicine-related injuries. Industry affiliation was defined as a funding source or author affiliation with the company that provided the biological product being studied. Extracted data included the reported purpose, conclusion, funding sources, researcher industry affiliations, sample size, minimum follow-up (FU) and the outcome metrics used. Two-tailed t-tests and logistic regression analyses were performed for analysis. Findings Ninety-eight studies met our inclusion criteria and included a total of 5898 subjects with a minimum FU of 6 weeks–24 months. These studies investigated shoulder, knee, foot and ankle, and elbow issues. Forty-eight of the 98 studies (49%) did not report the source of study funding. In total, 47 of the 98 studies (48%) reported favourable results, and 5 of these studies (10.6%) reported industry affiliations. Published studies with unknown funding sources reported conclusions in favour of the biological treatment significantly more often than those with reported funding sources (p=0.015). Conclusions and relevance Nearly half of the included studies did not disclose funding sources, and studies with unknown funding sources more frequently reported results in favour of the biological treatment. Clinical reports of randomised trials should emphasise reporting of funding sources to ensure data transparency and interpretability of results. Future initiatives should focus on developing standard international criteria for reporting research funding in scientific publications. Level of evidence II

Infection is a rare occurrence after revision anterior cruciate ligament reconstruction (rACLR). Because of the low rates of infection, it has been difficult to identify risk factors for infection in this patient population. The purpose of this study was to report the rate of infection following rACLR and assess whether infection is associated with patient- and surgeon- dependent risk factors. We reviewed two large prospective cohorts to identify patients with postoperative infections following rACLR. Age, sex, body mass index (BMI), smoking status, history of diabetes, and graft choice were recorded for each patient. The association of these factors with postoperative infection following rACLR was assessed. There were 1423 rACLR cases in the combined cohort, with 9 (0.6%) reporting post-operative infections. Allografts had a higher risk of infection than autografts (odds ratio=6.8; 95% CI: 0.9-54.5; p=0.045). Diabetes (odds ratio=28.6; 95% CI: 5.5-149.9; p=0.004) was a risk factor for infection. Patient age, sex, BMI and smoking status were not associated with risk of infection after rACLR. STATEMENT OF CLINICAL SIGNIFICANCE: While there is a low rate of infection following rACLR, use of allograft and comorbidity with diabetes are associated with a higher risk of infection following this surgery.

Background: The timing of return to play after anterior cruciate ligament (ACL) reconstruction is still controversial due to uncertainty of true ACL graft state at the time of RTP. Recent work utilizing ultra-short echo T2* (UTE-T2*) magnetic resonance imaging (MRI) as a scanner-independent method to objectively and non-invasively assess the status of in vivo ACL graft remodeling has produced promising results. Purpose/Hypothesis: The purpose of this study was to prospectively and noninvasively investigate longitudinal changes in T2* within ACL autografts at incremental time points up to 12 months after primary ACL reconstruction in human patients. We hypothesized that (1) T2* would increase from baseline and initially exceed that of the intact contralateral ACL, followed by a gradual decline as the graft undergoes remodeling, and (2) remodeling would occur in a region-dependent manner. Study Design: Case series; Level of evidence, 4. Methods: Twelve patients (age range, 14-45 years) who underwent primary ACL reconstruction with semitendinosus tendon or bone–patellar tendon–bone autograft (with or without meniscal repair) were enrolled. Patients with a history of previous injury or surgery to either knee were excluded. Patients returned for UTE MRI at 1, 3, 6, 9, and 12 months after ACL reconstruction. Imaging at 1 month included the contralateral knee. MRI pulse sequences included high-resolution 3-dimensional gradient echo sequence and a 4-echo T2-UTE sequence (slice thickness, 1 mm; repetition time, 20 ms; echo time, 0.3, 3.3, 6.3, and 9.3 ms). All slices containing the intra-articular ACL were segmented from high-resolution sequences to generate volumetric regions of interest (ROIs). ROIs were divided into proximal/distal and core/peripheral sub-ROIs using standardized methods, followed by voxel-to-voxel registration to generate T2* maps at each time point. This process was repeated by a second reviewer for interobserver reliability. Statistical differences in mean T2* values and mean ratios of T2*inj/T2*intact (ie, injured knee to intact knee) among the ROIs and sub-ROIs were assessed using repeated measures and one-way analyses of variance. P < .05 represented statistical significance. Results: Twelve patients enrolled in this prospective study, 2 withdrew, and ultimately 10 patients were included in the analysis (n = 7, semitendinosus tendon; n = 3, bone–patellar tendon–bone). Interobserver reliability for T2* values was good to excellent (intraclass correlation coefficient, 0.84; 95% CI, 0.59-0.94; P < .001). T2* values increased from 5.5 ± 2.1 ms (mean ± SD) at 1 month to 10.0 ± 2.9 ms at 6 months ( P = .001), followed by a decline to 8.1 ± 2.0 ms at 12 months ( P = .129, vs 1 month; P = .094, vs 6 months). Similarly, mean T2*inj/T2*intact ratios increased from 62.8% ± 22.9% at 1 month to 111.1% ± 23.9% at 6 months ( P = .001), followed by a decline to 92.8% ± 29.8% at 12 months ( P = .110, vs 1 month; P = .086, vs 6 months). Sub-ROIs exhibited similar increases in T2* until reaching a peak at 6 months, followed by a gradual decline until the 12-month time point. There were no statistically significant differences among the sub-ROIs ( P > .05). Conclusion: In this preliminary study, T2* values for ACL autografts exhibited a statistically significant increase of 82% between 1 and 6 months, followed by an approximate 19% decline in T2* values between 6 and 12 months. In the future, UTE-T2* MRI may provide unique insights into the condition of remodeling ACL grafts and may improve our ability to noninvasively assess graft maturity before return to play.

Background: Meniscal preservation has been demonstrated to contribute to long-term knee health. This has been a successful intervention in patients with isolated tears and tears associated with anterior cruciate ligament (ACL) reconstruction. However, the results of meniscal repair in the setting of revision ACL reconstruction have not been documented. Purpose: To examine the prevalence and 2-year operative success rate of meniscal repairs in the revision ACL setting. Study Design: Case-control study; Level of evidence, 3. Methods: All cases of revision ACL reconstruction with concomitant meniscal repair from a multicenter group between 2006 and 2011 were selected. Two-year follow-up was obtained by phone and email to determine whether any subsequent surgery had occurred to either knee since the initial revision ACL reconstruction. If so, operative reports were obtained, whenever possible, to verify the pathologic condition and subsequent treatment. Results: In total, 218 patients (18%) from 1205 revision ACL reconstructions underwent concurrent meniscal repairs. There were 235 repairs performed: 153 medial, 48 lateral, and 17 medial and lateral. The majority of these repairs (n = 178; 76%) were performed with all-inside techniques. Two-year surgical follow-up was obtained on 90% (197/218) of the cohort. Overall, the meniscal repair failure rate was 8.6% (17/197) at 2 years. Of the 17 failures, 15 were medial (13 all-inside, 2 inside-out) and 2 were lateral (both all-inside). Four medial failures were treated in conjunction with a subsequent repeat revision ACL reconstruction. Conclusion: Meniscal repair in the revision ACL reconstruction setting does not have a high failure rate at 2-year follow-up. Failure rates for medial and lateral repairs were both

Background: Anterior cruciate ligament (ACL) revision cohorts continually report lower outcome scores on validated knee questionnaires than primary ACL cohorts at similar time points after surgery. It is unclear how these outcomes are associated with physical activity after physician clearance for return to recreational or competitive sports after ACL revision surgery. Hypotheses: Participants who return to either multiple sports or a singular sport after revision ACL surgery will report decreased knee symptoms, increased activity level, and improved knee function as measured by validated patient-reported outcome measures (PROMs) and compared with no sports participation. Multisport participation as compared with singular sport participation will result in similar increased PROMs and activity level. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 1205 patients who underwent revision ACL reconstruction were enrolled by 83 surgeons at 52 clinical sites. At the time of revision, baseline data collected included the following: demographics, surgical characteristics, previous knee treatment and PROMs, the International Knee Documentation Committee (IKDC) questionnaire, Marx activity score, Knee injury and Osteoarthritis Outcome Score (KOOS), and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). A series of multivariate regression models were used to evaluate the association of IKDC, KOOS, WOMAC, and Marx Activity Rating Scale scores at 2 years after revision surgery by sports participation category, controlling for known significant covariates. Results: Two-year follow-up was obtained on 82% (986 of 1205) of the original cohort. Patients who reported not participating in sports after revision surgery had lower median PROMs both at baseline and at 2 years as compared with patients who participated in either a single sport or multiple sports. Significant differences were found in the change of scores among groups on the IKDC ( P < .0001), KOOS-Symptoms ( P = .01), KOOS–Sports and Recreation ( P = .04), and KOOS–Quality of Life ( P < .0001). Patients with no sports participation were 2.0 to 5.7 times more likely than multiple-sport participants to report significantly lower PROMs, depending on the specific outcome measure assessed, and 1.8 to 3.8 times more likely than single-sport participants (except for WOMAC-Stiffness, P = .18), after controlling for known covariates. Conclusion: Participation in either a single sport or multiple sports in the 2 years after ACL revision surgery was found to be significantly associated with higher PROMs across multiple validated self-reported assessment tools. During follow-up appointments, surgeons should continue to expect that patients who report returning to physical activity after surgery will self-report better functional outcomes, regardless of baseline activity levels.

Revision anterior cruciate ligament (ACL) reconstruction has been documented to have worse outcomes than primary ACL reconstruction. The reasons remain varied and not completely understood. METHODS: Patients undergoing revision ACL reconstruction were prospectively enrolled. Data collected included baseline demographics, surgical technique and pathological condition, prescribed rehabilitation instructions, and a series of validated patient-reported outcome instruments. Patients were followed for 2 years and asked to complete a set of outcome instruments identical to those completed at baseline. Subsequent surgical procedures on the ipsilateral knee were recorded. Regression analysis was used to control for age, sex, activity level, baseline outcome scores, and the above-mentioned rehabilitation-related variables in order to assess the factors affecting clinical outcomes 2 years after revision ACL reconstruction. RESULTS: A total of 843 patients met the inclusion criteria and were successfully enrolled, and 82% (695) were followed for 2 years. Two rehabilitation-related factors were found to influence outcome. First, patients who were prescribed an ACL brace for their return to sports had a significantly better Knee injury and Osteoarthritis Outcome Score (KOOS) for sports and recreational activities at 2 years (odds ratio [OR] =1.50, 95% confidence interval [CI] = 1.07 to 2.11; p = 0.019). Second, patients prescribed an ACL brace for the postoperative rehabilitation period were 2.3 times more likely to have subsequent surgery by 2 years (OR = 2.26, 95% CI = 1.11 to 4.60; p = 0.024). The odds of a graft rerupture were not affected by any type of brace wear. CONCLUSIONS: Rehabilitation-related factors that the physician can control at the time of an ACL reconstruction have the ability to influence clinical outcomes at 2 years. Weight-bearing and motion can be initiated immediately postoperatively. Bracing during the early postoperative period is not helpful. Use of a functional brace early in the postoperative period was associated with an increased risk of a reoperation. Use of a functional brace for a return to sports improved the KOOS on the sports/recreation subscale. LEVEL OF EVIDENCE: Prognostic Level I. See Instructions for Authors for a complete description of levels of evidence.

Classification systems should enhance communication between providers, facilitate accurate and consistent reporting in the literature, and guide management. However, current classification systems for MLKIs lack sufficient detail to guide clinical management which limit their prognostic value. The purpose of this chapter is to revisit and consider important features of some of the most impactful classification systems developed in the orthopaedic literature and to propose a classification system for MLKIs that may improve communication among providers, facilitate consistent reporting in the literature, and ultimately foster publication of meaningful clinical data.

It is critical to understand the details and complexity of injuries to the posterior cruciate ligament (PCL) and associated structures to best design a successful treatment plan. Most isolated PCL injuries can be treated non operatively but complete PCL injuries associated with other ligaments usually require surgical intervention. Successful surgery requires a detailed knowledge of the anatomy, pathophysiology and skilled surgical techniques that reproduce the normal anatomy.

Objectives: Post-reconstruction imaging of the anterior cruciate ligament (ACL) is needed to non-invasively assess in vivo graft maturity before release to play. The purpose of this study was to evaluate autograft remodeling up to 12 months after ACL reconstruction using 3D ultra-short time to echo (UTE) T2* MRI. We hypothesized that the T2* values of ACL autografts would progressively change over time, initially resembling the values for the native contralateral graft source and gradually approaching that of the intact contralateral ACL. Methods: After IRB approval, 12 patients (ages 14-45 years) who underwent primary ACL reconstruction (ACLR) with semitendinosus (SemiT) or bone-patellar tendon-bone (BTB) autograft were enrolled. Patients with a history of prior injury or surgery to either knee were excluded. Subjects returned for UTE MRIs at 1, 3, 6, 9, and 12 months after ACLR. Imaging at 1-month included the contralateral knee. All scans were performed on a Philips Ingenia 3T system. MRI pulse sequences included high-resolution 3D T2 (slice thickness: 0.6mm, TR: 18.7ms; TE: 11.5ms) and a four-echo T2 UTE (slice thickness: 1mm, TR: 20ms; TE: 0.3, 3.3, 6.3, and 9.3ms). Using high-resolution 3D T2 sequences at 1 month, all slices containing the intra-articular ACL were segmented semi-automatically to generate volumetric regions of interest (ROIs) (Materialise, Inc.; Leuven, Belgium). ROIs were divided into proximal/distal and core/peripheral sub-ROIs using standardized methods. Each ROI was co-registered voxel-by-voxel to T2* maps also obtained at 1 month. These T2* maps were then co-registered with those of subsequent time points. The segmentation process was repeated for the 1-, 3-, and 6-month time points by a second reviewer for inter-observer reliability (κ). Statistical differences among the ROIs and sub-ROIs of ACL autografts were assessed with repeated-measures ANOVA and two-tailed non-parametric t-tests. PResults: Twelve subjects were enrolled in this prospective study, and after 2 subjects withdrew, 10 subjects were included in the analysis (n=7 SemiT; n=3 BTB). Nine of 10 subjects attended all postoperative imaging sessions at the time of this writing. Inter-observer reliability for T2* values was found to be excellent (κ=0.832; 95% CI [0.70-0.91]; pConclusions: ACL autografts exhibited progressively increasing T2* values and T2*[inj]/T2*[intact] ratios up to 12 months after ACLR, and these changes appear to be region-dependent. UTE T2* MR imaging can provide unique insights into the condition of remodeling ACL grafts, and may improve our ability to non-invasively assess graft maturity before allowing patients to resume high-intensity activities.

This study aims to evaluate relationships among multiple ligament knee injury (MLKI) patterns as classified according to the knee dislocation (KD) classification and the types of surgical management pursued. We hypothesized that the KD classification would not be predictive of the types of surgical management, and that categorizing injuries according to additional injury features such as structure, chronicity, grade, and topographic location would be predictive of the types of surgical management. This is a Retrospective cohort study. This study was conducted at a level I trauma center with a 150-mile coverage radius. Query of our billing database was performed using combinations of 43 billing codes (International Classification of Diseases [ICD] 9, ICD-10, and Current Procedural Terminology) to identify patients from 2011 to 2015 who underwent operative management for MLKIs. There were operative or nonoperative treatment for individual ligamentous injuries, repair, or reconstruction of individual ligamentous injuries, and staging or nonstaging or nonstaging of each surgical procedure. The main outcome was the nature and timing of clinical management for specific ligamentous injury patterns. In total, 287 patients were included in this study; there were 199 males (69.3%), the mean age was 30.2 years (SD: 14.0), and the mean BMI was 28.8 kg/m2 (SD: 7.4). There were 212 injuries (73.9%) categorized as either KD-I or KD-V. The KD classification alone was not predictive of surgery timing, staging, or any type of intervention for any injured ligament (p > 0.05). Recategorization of injury patterns according to structure, chronicity, grade, and location revealed the following: partial non-ACL injuries were more frequently repaired primarily (p

We investigated the effects of isolated meniscectomy on tibiofemoral skeletal kinematics and cartilage contact arthrokinematics in vivo. We recruited nine patients who had undergone isolated medial or lateral meniscectomy, and used a dynamic stereo-radiography (DSX) system to image the patients' knee motion during decline walking. A volumetric model-based tracking process determined 3D tibiofemoral kinematics from the recorded DSX images. Cartilage contact arthrokinematics was derived from the intersection between tibial and femoral cartilage models co-registered to the bones. The kinematics and arthrokinematics were analyzed for early stance and loading response phase (30% of a gait cycle), comparing the affected and intact knees. Results showed that four patients with medial meniscectomy had significantly greater contact centroid excursions in the meniscectomized medial compartments while five patients with lateral meniscectomy had significantly greater cartilage contact area and lateral shift of contact centroid path in the meniscectomized lateral compartments, comparing to those of the same compartments in the contralateral intact knees. No consistent difference however was identified in the skeletal kinematics. The current study demonstrated that cartilage-based intra-articular arthrokinematics is more sensitive and insightful than the skeletal kinematics in assessing the meniscectomy effects.

Background:Articular cartilage health is an important issue following anterior cruciate ligament (ACL) injury and primary ACL reconstruction. Factors present at the time of primary ACL reconstruction may influence the subsequent progression of articular cartilage damage.Hypothesis:Larger meniscus resection at primary ACL reconstruction, increased patient age, and increased body mass index (BMI) are associated with increased odds of worsened articular cartilage damage at the time of revision ACL reconstruction.Study Design:Case-control study; Level of evidence, 3.Methods:Subjects who had primary and revision data in the databases of the Multicenter Orthopaedics Outcomes Network (MOON) and Multicenter ACL Revision Study (MARS) were included. Reviewed data included chondral surface status at the time of primary and revision surgery, meniscus status at the time of primary reconstruction, primary reconstruction graft type, time from primary to revision ACL surgery, as well as demographics and Marx activity score at the time of revision. Significant progression of articular cartilage damage was defined in each compartment according to progression on the modified Outerbridge scale (increase ≥1 grade) or >25% enlargement in any area of damage. Logistic regression identified predictors of significant chondral surface change in each compartment from primary to revision surgery.Results:A total of 134 patients were included, with a median age of 19.5 years at revision surgery. Progression of articular cartilage damage was noted in 34 patients (25.4%) in the lateral compartment, 32 (23.9%) in the medial compartment, and 31 (23.1%) in the patellofemoral compartment. For the lateral compartment, patients who had >33% of the lateral meniscus excised at primary reconstruction had 16.9-times greater odds of progression of articular cartilage injury than those with an intact lateral meniscus ( P < .001). For the medial compartment, patients who had Conclusion:Excision of the medial and lateral meniscus at primary ACL reconstruction increases the odds of articular cartilage damage in the corresponding compartment at the time of revision ACL reconstruction. Increased age is a risk factor for deterioration of articular cartilage in both tibiofemoral compartments, while increased BMI and the use of allograft for primary ACL reconstruction are associated with an increased risk of progression in the patellofemoral compartment.

Arthroscopic partial meniscectomy has been considered a gold standard treatment for meniscal tears for the past three decades, which has led to partial meniscectomy being the most commonly performed orthopaedic procedure in countries across three continents. Because of the prevalence of meniscal tears, there is a tremendous impact of their ‘simple' surgical management on the world's population. The management of degenerative meniscal tears has been changing due to numerous level I studies. While the majority of these studies find little difference between conservative management and partial meniscectomy, these studies have multiple exclusions and high cross-over rates from the non-surgical to the surgical groups. We present a review of the evidence and consensus statements from multiple continents on the treatment of degenerative meniscal tears.

Anterior cruciate ligament graft augmentation may protect the graft during the early phases of graft remodeling. A concern is stress-shielding, and recent time-zero biomechanical models are promising in this regard. To get the best answer, it will require in vivo healing studies conducted in animals, and eventually human studies using non-invasive imaging techniques, and ultimately clinical outcome studies including evaluation of return to play in athletes. For now, until additional research studies are available, this type of augmentation is best reserved as an option in carefully selected patients with a small graft size at the time of harvest.

Background Augmentation of soft-tissue repairs with an autologous fibrin clot has been used clinically for nearly four decades; however, fibrin clots tend to produce an abundance of scar tissue, which is known to inhibit soft-tissue regeneration. Mesenchymal stem cells (MSCs) embedded in fibrin clots before repair could reduce scar tissue deposition and facilitate soft-tissue regeneration. To our knowledge, no published studies have directly evaluated the viability or bioactivity of MSCs in fresh human fibrin clots over time. The purpose of this study was to evaluate the viability and bioactivity of human MSCs inside human fibrin clots over time in nutritive and non-nutritive culture media. Questions/purposes We hypothesized that human MSCs would (1) be captured inside fibrin clots and retain their proliferative capacity, (2) remain viable for at least 7 days in the fibrin clots, (3) maintain their proliferative capacity for at least 7 days in the fibrin clots without evidence of active apoptosis, and (4) display similar viability and proliferative capacity when cultured in a non-nutritive medium over the same time periods. Methods Twelve patients (mean age 33.7 years; range 4-72 years) who underwent elective knee surgery were approached between February 2016 and October 2017; all patients agreed to participate and were enrolled. MSCs isolated from human skeletal muscle and banked after prior studies were used for this analysis. On the day of surgery and after expansion of the MSC population, 3-mL aliquots of phosphate-buffered saline containing approximately 600,000 labeled with anti-green fluorescent protein (GFP) antibodies were transported to the operating room, mixed in 30 mL of venous blood from each enrolled patient, and stirred at 95 rpm for 10 minutes to create MSC-embedded fibrin clots. The fibrin clots were transported to the laboratory with their residual blood for analysis. Eleven samples were analyzed after exclusion of one sample because of a processing error. MSC capture was qualitatively demonstrated by enzymatically digesting half of each clot specimen, thus releasing GFP-positive MSCs into culture. The released MSCs were allowed to culture for 7 days. Manual counting of GFP-positive MSCs was performed at 2, 3, 4, and 7 days using an inverted microscope at 100 x magnification to document the change in the number of GFP-positive MSCs over time. The intact remaining half of each clot specimen was immediately placed in proliferation media and allowed to culture for 7 days. On Days 1, 2, 3, 4, and 7, a small portion of the clot was excised, flash-frozen, cryosectioned (8-μm thickness), and immunostained with antibodies specific to GFP, Ki67 (indicative of active proliferation), and cleaved caspase-3 ([CC3]; indicative of active apoptosis). Using an inverted microscope, we obtained MSC cell counts manually at time zero and after 1, 2, 3, 4, and 7 days of culture. Intact fresh clot specimens were immediately divided in half; one half was placed in nutritive (proliferation media) and the other was placed in non-nutritive (saline) media for 1, 2, 3, 4, and 7 days. At each timepoint, specimens were processed in an identical manner as described above, and a portion of each clot specimen was excised, immediately flash-frozen with liquid nitrogen, cryosectioned (8-μm thickness), and visualized at 200 x using an inverted microscope. The numbers of stain-positive MSCs per field of view, per culture condition, per timepoint, and per antibody stain type were counted manually for a quantitative analysis. Raw data were statistically compared using t-tests, and time-based correlations were assessed using Pearson's correlation coefficients. Two-tailed p values of less than 0.05 (assuming unequal variance) were considered statistically significant. Results Green fluorescence, indicative of viable GFP-positive MSCs, was absent in all residual blood samples after 48 hours of culturing; GFP-positive MSCs were visualized after enzymatic digestion of clot matrices. The number of GFP-positive MSCs per field of view increased between the 2-day and 7-day timepoints (mean 5.4 ± 1.5; 95% confidence interval, 4.7-6.1 versus mean 17.0 ± 13.6; 95% CI, 10.4-23.5, respectively; p = 0.029). Viable GFP-positive MSCs were present in each clot cryosection at each timepoint up to 7 days of culturing (mean 6.2 ± 4.3; 95% CI, 5.8-6.6). There were no differences in MSC counts between any of the timepoints. There was no visible evidence of GFP +/CC3 + double-positive MSCs. Combining all timepoints, there were 0.34 ± 0.70 (95% CI, 0.25-0.43) GFP+/Ki67+ double-positive MSCs per field of view. The mitotic indices at time zero and Day 7 were 7.5% ± 13.4% (95% CI, 3.0%-12.0%) and 7.2% ± 14.3% (95% CI, 3.3%-12,1%), respectively (p = 0.923). There was no visible evidence of GFP +/CC3 + double-positive MSCs (active apoptosis) at any timepoint. For active proliferation in saline-cultured fibrin clots, we found averages of 0.1 ± 0.3 (95% CI, 0.0-0.2) and 0.4 ± 0.9 (95% CI, 0.0-0.8) GFP/Ki67 double-positive MSCs at time zero and Day 7, respectively (p = 0.499). The mitotic indices in saline culture at time zero and Day 7 were 2.9% ± 8.4% (95% CI, 0.0%-5.8%) and 9.1% ± 20.7% (95% CI, 1.2%-17.0%; p = 0.144). There was no visible evidence of GFP +/CC3 + double-positive MSCs (active apoptosis) at any timepoint in either culturing condition. Conclusion These preliminary in vitro results show that human MSCs mixed in unclotted fresh human venous blood were nearly completely captured in fibrin clots and that seeded MSCs were capable of maintaining their viability, proliferation capacity, and osteogenic differentiation capacity in the fibrin clot for up to 7 days, independent of external sources of nutrition. Clinical relevance Fresh human fibrin clots have been used clinically for more than 30 years to improve soft-tissue healing, albeit with scar tissue. Our results demonstrate that allogenic human MSCs, which reduce soft-tissue scarring, can be captured and remain active inside human fibrin clots, even in the absence a nutritive culture medium.

Purpose To quantify the effects of lateral extra-articular tenodesis (LET) on tibiofemoral compartment contact area and pressures, knee kinematics, and forces. Methods Nine cadaveric knees were tested using a robotic testing system. Two loading conditions, (1) anterior tibial translational load coupled with axial compression and (2) internal tibial torque coupled with axial compression, were applied for each knee state at full extension and 30°, 60°, and 90° of knee flexion. Kinematic data was recorded for 3 knee states: anterolateral capsule (ALC) competent, ALC deficient, and post-LET using a 6-mm semitendinosus graft. In situ force in the anterior cruciate ligament (ACL) was quantified using the principle of superposition by comparing the change in force measured before and after the removal of the ALC. Contact area and pressures in each tibiofemoral compartment were measured by replaying kinematics after soft tissues were removed and pressure sensors were inserted. Results In response to an anterior tibial translational load, mean contact area in the medial compartment decreased by 33.1% from the ALC-competent to post-LET knee states at 90° of knee flexion (P = .042). No significant differences in lateral compartment contact pressure were found between knee states. In situ force in the ACL in response to an anterior tibial translational load decreased by 43.4% and 50% from the ALC-deficient to post-LET knee states at 60° (P = .02) and 90° (P = .006). No significant difference in kinematics was observed between the ALC-competent and post-LET knee states in each of the loading conditions at all knee flexion angles (P > .05). Conclusions In this in vitro model, LET with a semitendinosus graft did not significantly overconstrain the knee or increase pressure in the lateral compartment. Additionally, LET reduced the in situ force in the ACL in the setting of ALC injury. Clinical Relevance The lack of knee overconstraint without significant increases in lateral compartment pressures indicates that if an LET with semitendinosus graft is not overtensioned, accelerated degenerative changes in the lateral compartment may not be expected after this procedure.

Objectives: Chronic rotator cuff tears still represent a significant source of morbidity and functional decline in the general population. The purpose of this study was to establish protocols for isolation and expansion of bursa-derived mesenchymal stem cells (BDSCs) and to evaluate their differentiation capacity, including tenogenesis. We hypothesized that BDSCs would be capable of multilineage differentiation (including tenogenesis) and represent an important source for autologous stem cells for patients undergoing rotator cuff repair. Methods: After IRB approval, 10 patients (ages 43-65 years) scheduled to undergo arthroscopic repair for chronic rotator cuff tears were enrolled. During diagnostic arthroscopy, subacromial bursa tissue was harvested using an arthroscopic shaver and collected by attaching the outflow tubing to a specialized specimen cup. Tissue specimens were transported to our laboratory for analysis. BDSCs were isolated via adherent culture and plated in Dulbecco’s Modified Eagle’s Medium (DMEM) supplemented with 10% Fetal Bovine Serum (FBS). Chondrogenic, adipogenic, and osteogenic induction media were used to induce differentiation. Tenogenic induction was performed using DMEM supplemented with varying concentrations of BMP-12, ascorbic acid, and human tenocyte-conditioned media. Alcian Blue staining was used to evaluate chondrogenesis, Oil Red O staining for adipogenesis, and Alkaline Phosphatase staining for osteogenesis. Gene expression markers for adipogenesis (ADIPOQ, FABP4, PPARγ), chondrogenesis (COL2A1 and SOX5), and osteogenesis (osteocalcin, osterix), along with primary antibodies to tenogenic markers (scleraxis, tenomodulin), were used to verify each cell lineage. Results: BDSCs isolated by adherent culture without collagen exhibited a spindle-shaped morphology characteristic of mesenchymal stem cells (MSCs), formed colonies, and demonstrated great expandability for six to eight passages without morphology changes (Figure 1A). After 3 weeks of culture, 95% (pConclusion: Our results demonstrate that subacromial bursa represents a viable source of mesenchymal stem cells. We developed a reliable protocol for isolation of BDSCs from patient bursa samples. We show that BDSCs in the presence of BMP-12 and ascorbic acid can differentiate toward a tenogenic lineage. Our work provides strong evidence that BDSCs may be a potent tool for cellular therapy and may benefit future patients who undergo surgical repair of chronic rotator cuff tears. [Figure: see text][Figure: see text]

Athletic team coverage experience varies widely across orthopedic surgery residency programs in the United States. There is a paucity of literature regarding whether serving as a team physician contributes to resident education and whether it can be performed within the bounds of current work-hour restrictions. Residents consider coverage of high school football games a valuable educational experience that does not adversely affect their 80-hour work week. Sixty-one orthopedic residents who served as high school football team physicians as part of their residency curriculum completed an 11-question survey. Responses ranged from strongly agree (1) to strongly disagree (5) on a Likert scale. The majority of residents agreed that serving as a team physician was an overall valuable experience (85%), that it enhanced their orthopedic sports medicine education (89%), and that it increased their awareness of the role played by athletic trainers (97%). The majority of respondents disagreed only with the statement that serving as a team physician had negatively affected their 80-hour work week (54%), and an additional 26% neither agreed nor disagreed. The vast majority of participating orthopedic residents consider high school football team coverage a valuable experience that enhances education and can be performed within work-hour limitations. [ Orthopedics . 2020;43(6):e574–e578.]

Background: Bone–patellar tendon–bone (BTB) grafts are generally believed to heal more quickly than soft tissue grafts after anterior cruciate ligament (ACL) reconstruction, but little is known about the time course of healing or motion of the grafts within the bone tunnels. Hypothesis: Graft-tunnel motion will be greater in hamstring (HS) grafts compared with BTB grafts and will be less at 1 year than at 6 weeks. Study Design: Controlled laboratory study. Methods: Twelve patients underwent anatomic single-bundle ACL reconstruction using HS or BTB autografts (6 per group) with six 0.8-mm tantalum beads embedded in each graft. Dynamic stereo x-ray images were collected at 6 weeks and 1 year during treadmill walking and stair descent and at 1 year during treadmill running. Tibiofemoral kinematics and bead positions were evaluated. Graft-tunnel motion was based on bead range of motion during the loading response phase (first 10%) of the gait cycle. Results: During treadmill walking, there was no difference in femoral tunnel or tibial tunnel motion between BTB or HS grafts at 6 weeks (BTB vs HS: 2.00 ± 1.05 vs 1.25 ± 0.67 mm [femoral tunnel]; 1.20 ± 0.63 vs 1.27 ± 0.71 mm [tibial tunnel]), or 1 year (BTB vs HS: 1.62 ± 0.76 vs 1.08 ± 0.26 mm [femoral tunnel]; 1.58 ± 0.75 vs 1.68 ± 0.53 mm [tibial tunnel]). During stair descent, there was no difference in femoral or tibial tunnel motion between BTB and HS grafts at 6 weeks or 1 year. With running, there was no difference between graft types at 1 year. For all results, P values were > .05. Knee kinematics were consistent with the literature. Conclusion: During walking and stair descent, ACL reconstruction using suspensory fixation yielded no difference between graft types in femoral or tibial tunnel motion at 6 weeks or 1 year. All subjects were asymptomatic with knee kinematics similar to that of the literature. The significance of persistent, small (1 to 3 mm) movements at 1 year for healing or graft performance is unknown. Clinical Relevance: These study results may have significant implications for graft choice, rehabilitation strategies, and timing for return to sports.

Background:Revision anterior cruciate ligament (ACL) reconstruction has been documented to have worse outcomes compared with primary ACL reconstructions.Purpose/Hypothesis:The purpose of this study was to determine if the prevalence, location, and/or degree of meniscal and chondral damage noted at the time of revision ACL reconstruction predicts activity level, sports function, and osteoarthritis symptoms at 2-year follow-up. The hypothesis was that meniscal loss and high-grade chondral damage noted at the time of revision ACL reconstruction will result in lower activity levels, decreased sports participation, more pain, more stiffness, and more functional limitation at 2 years after revision surgery.Study Design:Cohort study; Level of evidence, 2.Methods:Between 2006 and 2011, a total of 1205 patients who underwent revision ACL reconstruction by 83 surgeons at 52 hospitals were accumulated for study of the relationship of meniscal and articular cartilage damage to outcome. Baseline demographic and intraoperative data, including the International Knee Documentation Committee (IKDC) subjective knee evaluation, Knee injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Marx activity score, were collected initially and at 2-year follow-up to test the hypothesis. Regression analysis was used to control for age, sex, body mass index, smoking status, activity level, baseline outcome scores, revision number, time since last ACL reconstruction, incidence of having a previous ACL reconstruction on the contralateral knee, previous and current meniscal and articular cartilage injury, graft choice, and surgeon years of experience to assess the meniscal and articular cartilage risk factors for clinical outcomes 2 years after revision ACL reconstruction.Results:At 2-year follow-up, 82% (989/1205) of the patients returned their questionnaires. It was found that previous meniscal injury and current articular cartilage damage were associated with the poorest outcomes, with prior lateral meniscectomy and current grade 3 to 4 trochlear articular cartilage changes having the worst outcome scores. Activity levels at 2 years were not affected by meniscal or articular cartilage pathologic changes.Conclusion:Prior lateral meniscectomy and current grade 3 to 4 changes of the trochlea were associated with worse outcomes in terms of decreased sports participation, more pain, more stiffness, and more functional limitation at 2 years after revision surgery, but they had no effect on activity levels.Registration:NCT00625885

‘Nothing ruins good results like long term follow-up.‘ About 43 years ago, 2 bright young academic orthopaedic team doctors decided to review the results of anterior cruciate ligament (ACL) repair in their West Point cadet population. These initial results seemed very promising (greater than 80% good-to-excellent outcomes) at the 2-year follow-up published as an abstract in the Journal of Bone and Joint Surgery in 1972; however, instead of resting on their 2-year outcomes, they made the decision to look at this same group 5 years after surgery. What they found was very alarming and humbling in that the majority of this population had poor outcomes. Being of the highest moral integrity and calibre, they wrote up their results and submitted it to the American Journal of Sports Medicine in 1976. Ironically, the editor of the journal was the legendary Jack Hughston who was well known not to be an advocate of ACL surgery. This article most likely further fuelled his beliefs (‘gasoline on the fire', so to say!). Since this publication over 40 years ago, there has been an explosion of basic science and clinical papers on ACL anatomy, biomechanics, healing, injury and surgical techniques. The purpose of revisiting this ‘Classic' article is to acquire perspectives from both the original authors, Dr John Feagin and Dr Walton Curl, in conjunction with Dr Martha Murray, who is considered one of the leading experts on the science of ACL repair. This article begins with a detailed review of this ‘Classic' and highlights the main take home points. Next, there is a discussion about the historical perspectives, the scientific and societal impact, and where we are today with basic and clinical science studies. We conclude with where we are with ACL repair in 2016 and make recommendations based on current evidence for this procedure in the spectrum of ACL surgery. The ultimate goal of this review is to expose our readership to the potential use of these techniques for select patients with ACL injuries. Most importantly, one must not overlook the primary take home message of this ‘Classic Revisited', that careful and honest long-term follow-up is the key to evidence-based medicine.

The management of posterior cruciate ligament (PCL) injuries is associated with a relatively high rate of complications compared with other ligamentous injuries. PCL injuries are most frequently encountered in the setting of multiligamentous knee injuries, and are less commonly diagnosed in isolation. An understanding of the commonly encountered complications in the evaluation, preoperative management, intraoperative management, postoperative management, and rehabilitation of PCL injury is integral to mitigating events that can lead to poor outcomes. This chapter will review the common pitfalls associated with PCL injury and management, along with strategies to prevent or address these complications.

Chronic knee dislocations are among the most complex set of knee pathologies managed by orthopedic surgeons. They represent a broad range of diagnoses that involve two to four injured collateral and/or cruciate ligaments. Also, there are frequent concomitant injuries to the posteromedial and posterolateral corners of the knee and the menisci with possible resultant malalignment, neurovascular injuries, and venous thromboses. These patients often present with a knee that is simultaneously stiff and unstable. The purpose of this chapter is to provide a reproducible way to determine a complete diagnosis followed by detailed nonsurgical and surgical management of the knee through the postoperative rehabilitation process.

To compare femoral nerve blockade (FNB) versus adductor canal nerve blockade (ACB) for postoperative pain control and quadriceps muscle function in patients undergoing anterior cruciate ligament (ACL) reconstruction with patellar tendon autograft.A randomized therapeutic trial of 90 patients undergoing ACL reconstruction with patellar tendon autograft was conducted comparing ACB versus FNB at 24 hours, 2 and 4 weeks, and 6 months postsurgery. Early outcome measures included average pain score and morphine equivalent units (milligrams) consumed, quadriceps surface electromyography, straight leg raise, and ability to ambulate without assistive devices. The 6-month outcome measures included knee range of motion (ROM), isokinetic knee extension peak torque, single-leg squat, and single-leg hop performance. Complications were recorded throughout the study for the development of anterior knee pain, knee extension ROM loss, deep vein thrombosis, and graft failure. Mixed-model analysis of variance and Mann-Whitney U tests were performed using an alpha of .05.Quadriceps surface electromyography deficits were higher for FNB at 24 hours (P.001) and 2 weeks (P.001) when compared with the ACB group. There were no between-groups difference for subjective pain (P = .793) or morphine consumption (P = .358) within the first 24 hours of surgery. A higher percentage of patients in the ACB group met the full ambulation criteria at 4 weeks compared with the FNB group (100% vs 84.2%, P.001). No between-group differences were observed at 6 months; however, the rate of knee extension ROM loss was higher for the FNB group versus the ACB group (21.1% vs 5.0%, P = .026), respectively.ACB was as effective as FNB at providing pain control while eliciting fewer quadriceps muscle activation deficits and fewer postoperative complications. Based on previous evidence and the results of this study, we recommend the use of ACB over FNB for the analgesic management of patients undergoing ACL reconstruction with patellar tendon autograft.Level I, prospective randomized controlled trial.

Background: The occurrence of physiologic knee hyperextension (HE) in the revision anterior cruciate ligament reconstruction (ACLR) population and its effect on outcomes have yet to be reported. Hypothesis/Purpose: The prevalence of knee HE in revision ACLR and its effect on 2-year outcome were studied with the hypothesis that preoperative physiologic knee HE ≥5° is a risk factor for anterior cruciate ligament (ACL) graft rupture. Study Design: Cohort study; Level of evidence, 2. Methods: Patients undergoing revision ACLR were identified and prospectively enrolled between 2006 and 2011. Study inclusion criteria were patients undergoing single-bundle graft reconstructions. Patients were followed up at 2 years and asked to complete an identical set of outcome instruments (International Knee Documentation Committee, Knee injury and Osteoarthritis Outcome Score, WOMAC, and Marx Activity Rating Scale) as well as provide information regarding revision ACL graft failure. A regression model with graft failure as the dependent variable included age, sex, graft type at the time of the revision ACL surgery, and physiologic preoperative passive HE ≥5° (yes/no) to assess these as potential risk factors for clinical outcomes 2 years after revision ACLR. Results: Analyses included 1145 patients, for whom 2-year follow-up was attained for 91%. The median age was 26 years, with age being a continuous variable. Those below the median were grouped as “younger” and those above as “older” (age: interquartile range = 20, 35 years), and 42% of patients were female. There were 50% autografts, 48% allografts, and 2% that had a combination of autograft plus allograft. Passive knee HE ≥5° was present in 374 (33%) patients in the revision cohort, with 52% being female. Graft rupture at 2-year follow-up occurred in 34 cases in the entire cohort, of which 12 were in the HE ≥5° group (3.2% failure rate) and 22 in the non-HE group (2.9% failure rate). The median age of patients who failed was 19 years, as opposed to 26 years for those with intact grafts. Three variables in the regression model were significant predictors of graft failure: younger age (odds ratio [OR] = 3.6; 95% CI, 1.6-7.9; P = .002), use of allograft (OR = 3.3; 95% CI, 1.5-7.4; P = .003), and HE ≥5° (OR = 2.12; 95% CI, 1.1-4.7; P = .03). Conclusion: This study revealed that preoperative physiologic passive knee HE ≥5° is present in one-third of patients who undergo revision ACLR. HE ≥5° was an independent significant predictor of graft failure after revision ACLR with a >2-fold OR of subsequent graft rupture in revision ACL surgery. Registration: NCT00625885 ( ClinicalTrials.gov identifier).

Regardless of the technique utilized, tunnel expansion following anterior cruciate ligament reconstruction remains a mystery and a clinical challenge. No procedure seems to be immune to this, even anatomic double-bundle reconstruction. This technique was introduced more than 20 years ago and showed great promise while also contributing significantly to our current knowledge of anterior cruciate ligament anatomy and biomechanics. However, we must remember that new techniques do carry with them new side effects that we must document and acknowledge if we hope to improve our surgical outcomes.

Posterolateral corner injuries are rare, and the examination to quantitate these injuries is very challenging. Careful examination comparing the involved and uninvolved knees, considering stress radiographs, and combining this with magnetic resonance imaging findings is currently our most accurate way to grade these injuries.

Background: Revision anterior cruciate ligament (ACL) reconstruction has been documented to have worse outcomes compared with primary ACL reconstruction. Hypothesis: Certain factors under the control of the surgeon at the time of revision surgery can both negatively and positively affect outcomes. Study Design: Case-control study; Level of evidence, 3. Methods: Patients undergoing revision ACL reconstruction were identified and prospectively enrolled between 2006 and 2011. Data collected included baseline demographics, intraoperative surgical technique and joint disorders, and a series of validated patient-reported outcome instruments (International Knee Documentation Committee [IKDC] subjective form, Knee Injury and Osteoarthritis Outcome Score [KOOS], Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], and Marx activity rating scale) completed before surgery. Patients were followed up for 2 years and asked to complete an identical set of outcome instruments. Regression analysis was used to control for age, sex, body mass index (BMI), activity level, baseline outcome scores, revision number, time since last ACL reconstruction, and a variety of previous and current surgical variables to assess the surgical risk factors for clinical outcomes 2 years after revision ACL reconstruction. Results: A total of 1205 patients (697 male [58%]) met the inclusion criteria and were successfully enrolled. The median age was 26 years, and the median time since their last ACL reconstruction was 3.4 years. Two-year follow-up was obtained on 82% (989/1205). Both previous and current surgical factors were found to be significant contributors toward poorer clinical outcomes at 2 years. Having undergone previous arthrotomy (nonarthroscopic open approach) for ACL reconstruction compared with the 1-incision technique resulted in significantly poorer outcomes for the 2-year IKDC ( P = .037; odds ratio [OR], 2.43; 95% CI, 1.05-5.88) and KOOS pain, sports/recreation, and quality of life (QOL) subscales ( P ≤ .05; OR range, 2.38-4.35; 95% CI, 1.03-10.00). The use of a metal interference screw for current femoral fixation resulted in significantly better outcomes for the 2-year KOOS symptoms, pain, and QOL subscales ( P ≤ .05; OR range, 1.70-1.96; 95% CI, 1.00-3.33) as well as WOMAC stiffness subscale ( P = .041; OR, 1.75; 95% CI, 1.02-3.03). Not performing notchplasty at revision significantly improved 2-year outcomes for the IKDC ( P = .013; OR, 1.47; 95% CI, 1.08-1.99), KOOS activities of daily living (ADL) and QOL subscales ( P ≤ .04; OR range, 1.40-1.41; 95% CI, 1.03-1.93), and WOMAC stiffness and ADL subscales ( P ≤ .04; OR range, 1.41-1.49; 95% CI, 1.03-2.05). Factors before revision ACL reconstruction that increased the risk of poorer clinical outcomes at 2 years included lower baseline outcome scores, a lower Marx activity score at the time of revision, a higher BMI, female sex, and a shorter time since the patient’s last ACL reconstruction. Prior femoral fixation, prior femoral tunnel aperture position, and knee flexion angle at the time of revision graft fixation were not found to affect 2-year outcomes in this revision cohort. Conclusion: There are certain surgical variables that the physician can control at the time of revision ACL reconstruction that can modify clinical outcomes at 2 years. Whenever possible, opting for an anteromedial portal or transtibial surgical exposure, choosing a metal interference screw for femoral fixation, and not performing notchplasty are associated with significantly better 2-year clinical outcomes.

Background: While revision anterior cruciate ligament reconstruction (ACLR) can be performed to restore knee stability and improve patient activity levels, outcomes after this surgery are reported to be inferior to those after primary ACLR. Further reoperations after revision ACLR can have an even more profound effect on patient satisfaction and outcomes. However, there is a current lack of information regarding the rate and risk factors for subsequent surgery after revision ACLR. Purpose: To report the rate of reoperations, procedures performed, and risk factors for a reoperation 2 years after revision ACLR. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 1205 patients who underwent revision ACLR were enrolled in the Multicenter ACL Revision Study (MARS) between 2006 and 2011, composing the prospective cohort. Two-year questionnaire follow-up was obtained for 989 patients (82%), while telephone follow-up was obtained for 1112 patients (92%). If a patient reported having undergone subsequent surgery, operative reports detailing the subsequent procedure(s) were obtained and categorized. Multivariate regression analysis was performed to determine independent risk factors for a reoperation. Results: Of the 1112 patients included in the analysis, 122 patients (11%) underwent a total of 172 subsequent procedures on the ipsilateral knee at 2-year follow-up. Of the reoperations, 27% were meniscal procedures (69% meniscectomy, 26% repair), 19% were subsequent revision ACLR, 17% were cartilage procedures (61% chondroplasty, 17% microfracture, 13% mosaicplasty), 11% were hardware removal, and 9% were procedures for arthrofibrosis. Multivariate analysis revealed that patients aged Conclusion: There was a significant reoperation rate after revision ACLR at 2 years (11%), with meniscal procedures most commonly involved. Independent risk factors for subsequent surgery on the ipsilateral knee included age

Background: Most surgeons believe that graft choice for anterior cruciate ligament (ACL) reconstruction is an important factor related to outcome; however, graft choice for revision may be limited due to previously used grafts. Hypotheses: Autograft use would result in increased sports function, increased activity level, and decreased osteoarthritis symptoms (as measured by validated patient-reported outcome instruments). Autograft use would result in decreased graft failure and reoperation rate 2 years after revision ACL reconstruction. Study Design: Cohort study; Level of evidence, 2. Methods: Patients undergoing revision ACL reconstruction were identified and prospectively enrolled by 83 surgeons at 52 sites. Data collected included baseline demographics, surgical technique, pathologic abnormalities, and the results of a series of validated, patient-reported outcome instruments (International Knee Documentation Committee [IKDC], Knee injury and Osteoarthritis Outcome Score [KOOS], Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], and Marx activity rating score). Patients were followed up at 2 years and asked to complete the identical set of outcome instruments. Incidences of additional surgery and reoperation due to graft failure were also recorded. Multivariate regression models were used to determine the predictors (risk factors) of IKDC, KOOS, WOMAC, Marx scores, graft rerupture, and reoperation rate at 2 years after revision surgery. Results: A total of 1205 patients (697 [58%] males) were enrolled. The median age was 26 years. In 88% of patients, this was their first revision, and 341 patients (28%) were undergoing revision by the surgeon who had performed the previous reconstruction. The median time since last ACL reconstruction was 3.4 years. Revision using an autograft was performed in 583 patients (48%), allograft was used in 590 (49%), and both types were used in 32 (3%). Questionnaire follow-up was obtained for 989 subjects (82%), while telephone follow-up was obtained for 1112 (92%). The IKDC, KOOS, and WOMAC scores (with the exception of the WOMAC stiffness subscale) all significantly improved at 2-year follow-up ( P < .001). In contrast, the 2-year Marx activity score demonstrated a significant decrease from the initial score at enrollment ( P < .001). Graft choice proved to be a significant predictor of 2-year IKDC scores ( P = .017). Specifically, the use of an autograft for revision reconstruction predicted improved score on the IKDC ( P = .045; odds ratio [OR] = 1.31; 95% CI, 1.01-1.70). The use of an autograft predicted an improved score on the KOOS sports and recreation subscale ( P = .037; OR = 1.33; 95% CI, 1.02-1.73). Use of an autograft also predicted improved scores on the KOOS quality of life subscale ( P = .031; OR = 1.33; 95% CI, 1.03-1.73). For the KOOS symptoms and KOOS activities of daily living subscales, graft choice did not predict outcome score. Graft choice was a significant predictor of 2-year Marx activity level scores ( P = .012). Graft rerupture was reported in 37 of 1112 patients (3.3%) by their 2-year follow-up: 24 allografts, 12 autografts, and 1 allograft and autograft. Use of an autograft for revision resulted in patients being 2.78 times less likely to sustain a subsequent graft rupture compared with allograft ( P = .047; 95% CI, 1.01-7.69). Conclusion: Improved sports function and patient-reported outcome measures are obtained when an autograft is used. Additionally, use of an autograft shows a decreased risk in graft rerupture at 2-year follow-up. No differences were noted in rerupture or patient-reported outcomes between soft tissue and bone–patellar tendon–bone grafts. Surgeon education regarding the findings of this study has the potential to improve the results of revision ACL reconstruction.

Background: Knee arthroscopies are among the most common procedures performed by orthopaedic surgeons, yet little is known about the associated complications and complication rates. Purpose: To examine the nature and frequency of complications after the most common arthroscopic knee procedures, with particular attention to fellowship training, geographic location of practice, and age and sex of the patient. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Data were obtained from the American Board of Orthopaedic Surgery database for orthopaedic surgeons who sat for the part II examination from 2003 to 2009. The database was queried to determine the type and frequency of complications for patients who underwent knee arthroscopy and for those who underwent sports medicine knee arthroscopy, including arthroscopic partial meniscectomy, meniscal repair, chondroplasty, microfracture, anterior cruciate ligament reconstruction, or posterior cruciate ligament reconstruction. Factors affecting complication rates that were investigated included type of procedure, fellowship training status, geographic location of practice, and age and sex of the patient. Results: There were 4305 complications out of 92,565 knee arthroscopic procedures obtained from the American Board of Orthopaedic Surgery database for an overall candidate-reported complication rate of 4.7%. The complication rates were highest for posterior cruciate ligament reconstruction (20.1%) and anterior cruciate ligament reconstruction (9.0%); complication rates for meniscectomy, meniscal repair, and chondroplasty were 2.8%, 7.6%, and 3.6%, respectively. The complication rate for sports fellowship–trained candidates was higher than for non–sports trained candidates (5.1% sports, 4.1% no sports; P < .0001) and for male patients (4.9% male vs 4.3% female; P < .0001). Younger patients (Conclusion: The overall self-reported complication rate for arthroscopic knee procedures was 4.7%. Knee arthroscopy is not a benign procedure, and patients should be aware of the risk of complications.

Aim To investigate the utility of the coronal oblique sequence in the interrogation of posterior root meniscal lesions. Materials and methods Following international review board approval, 62 consecutive knee arthroscopy cases were referred to the musculoskeletal (MSK) radiologists from the same orthopaedic surgeon for imaging/surgical correlation of the posterior meniscal roots. Of 62 cases, 45 lateral and 46 medial menisci met the inclusion criteria. Imaging evaluation was performed with standard magnetic resonance imaging (MRI) sequences, including a coronal oblique proton density sequence. Two blinded fellowship-trained MSK radiologists independently evaluated the menisci on standard sequences indicating whether a tear was identified and then specifying a confidence score using a scale of 1–3 on each study interpreted. Immediately thereafter, the coronal oblique sequence was evaluated using the same method. Statistics were performed on meniscal lesions involving the posterior horn/root junction or isolated root tears comparing confidence scores. Results Reader A identified nine posterior horn/root junction tears and 14 isolated root tears. Following the addition of the coronal oblique sequence, confidence scores increased in three of 14 (21.4%) isolated root tears. All three final reads were concordant with arthroscopy. Reader B identified 10 posterior horn/root junction tears and 19 isolated root tears. The confidence score increased in six cases: five of 19 (26.3%) isolated root tears and one of 10 (10%) posterior horn/root junction tears. All six final reads were concordant with arthroscopy. Kappa coefficients indicated near perfect agreement. Conclusion The coronal oblique sequence increased reader confidence in nearly 24% of the posterior root cases identified in this series.

Anterior cruciate ligament (ACL) reconstruction in most cases is an elective surgery with many potential complications. Early (non-emergent) surgery may increase the risk of certain complications including significant postoperative stiffness with loss of motion. Delaying surgery by a few weeks to allow the acutely injured knee to regain motion and gain quad control decreases the risk for these adverse effects. However, delayed ACL reconstruction with the intent of returning to normal activities months after the initial injury may lead to an increased risk of injury to cartilage and menisci. By choosing a delayed surgical treatment pathway, we are not intending to return the patient to sports; rather, we plan to get them through the acute inflammatory phase prior to reconstruction. We know by experience and by numerous well-designed studies that returning a patient with a potentially unstable knee to at risk activities including sports and certain occupations can lead to further injuries with irreversible damage.

Anterior cruciate ligament (ACL) reconstruction rehabilitation protocols for the acute postsurgical phase are prevalent. Protocols to guide rehabilitation through the return-to-sport progressions and phases are not as widely available. The purpose of this clinical review is to present the protocol developed at the University of Pittsburgh Medical Center (UMPC) Center for Sports Medicine for the late phases of rehabilitation and return-to-sport progress after ACL reconstruction with references to the literature.

Anterior cruciate ligament (ACL) surgery continues to evolve as we gain a better understanding of the anatomy and biomechanics of the ACL. In the late 1980s, there was a shift from a two-incision (rear-entry guide) to a single-incision (transtibial) technique. The impetus driving this was the potential to achieve equivalent tunnel placement more quickly and in a more cosmetic fashion1. However, when anatomic studies clearly defined the ACL femoral insertion site on the lateral intercondylar wall and not the roof, it was discovered that even when performed as described in the Surgical Techniques supplement of The Journal of Bone & Joint Surgery in 20052, the traditional transtibial technique placed the femoral tunnel higher (toward the apex of the notch as opposed to the wall) on the intercondylar notch, outside the native insertion site (Fig. 1)3-6. Some surgeons postulated that, even with adjustments to the traditional transtibial technique, transtibial drilling would always place the femoral tunnel higher on the intercondylar notch than the location of the native insertion site (Fig. 2, A ). In order to avoid placing the femoral tunnel on the intercondylar roof as is commonly associated with the transtibial technique (also known as the …

An imaging software system was studied for improving the performance of anatomic anterior cruciate ligament (ACL) reconstruction which requires identifying ACL insertion sites for bone tunnel placement. This software predicts and displays the insertion sites based on the literature data and patient-specific bony landmarks. Twenty orthopaedic surgeons performed simulated arthroscopic ACL surgeries on 20 knee specimens, first without and then with the visual guidance by fluoroscopic imaging, and their tunnel entry positions were recorded. The native ACL insertion morphologies of individual specimens were quantified in relation to CT-based bone models and then used to evaluate the software-generated insertion locations. Results suggested that the system was effective in leading surgeons to predetermined locations while the application of averaged insertion morphological information in individual surgeries can be susceptible to inaccuracy and uncertainty. Implications on challenges associated with developing engineering solutions to aid in re-creating or recognizing anatomy in surgical care delivery are discussed.

Background: Recently there have been several evolving trends in the practice of shoulder surgery. Arthroscopic subacromial decompression has been performed with greater frequency by orthopaedic surgeons, and there has been considerable recent interest in arthroscopic rotator cuff repair. The purpose of this study was to identify trends in practice patterns for subacromial decompression and rotator cuff repair over time and in relation to the location of practice, fellowship training, and declared subspecialty of the surgeon. Methods: We reviewed the American Board of Orthopaedic Surgery Part II database to identify patterns in the utilization of open and arthroscopic subacromial decompression and rotator cuff repair among candidates for board certification. All procedures involving only arthroscopic or open subacromial decompression and/or rotator cuff repair from 2004 to 2009 were identified. The rates of arthroscopic and open subacromial decompression and/or rotator cuff repair were compared in terms of year, geographic region, fellowship training, and declared subspecialty of the surgeon. Results: Between 2004 and 2009, 12,136 surgical procedures involving only arthroscopic or open subacromial decompression and/or rotator cuff repair were performed. There were significant differences in treatment with respect to year, geographic region of practice, declared subspecialty, and fellowship training (p < 0.001). There was a significant increase over time in the utilization of arthroscopy among all candidates (p < 0.001). Surgeons with sports medicine fellowship training or a sports-medicine-declared subspecialty performed significantly more subacromial decompressions and rotator cuff repairs arthroscopically than all other candidates (p < 0.001). During this time period, there was a significant decrease in the rate of arthroscopic subacromial decompression, both as an isolated procedure and combined with arthroscopic rotator cuff repair (p < 0.001). Conclusions: From 2004 to 2009, there was a significant shift throughout the United States toward arthroscopic rotator cuff repair and subacromial decompression among young orthopaedic surgeons, with sports medicine fellowship-trained surgeons performing more of their procedures arthroscopically than surgeons with other training. However, there was an increasing frequency of arthroscopic rotator cuff repair performed without subacromial decompression, and, overall, there was a decrease in the frequency of isolated arthroscopic subacromial decompression over time.

Combined injury to the anterior cruciate ligament (ACL) and posterolateral structures of the knee is a rare yet increasingly recognized clinical entity. In children or adolescents with open growth plates, this injury pattern is considered to be even more rare than in adults. Because knee ligaments are felt to be stronger than the adjacent physeal plates, the energy of pathologic translational and rotatory stress commonly results in fracture or avulsion injuries rather than ligamentous injury. The appropriate treatment for either injury remains controversial in the skeletally immature patient, with no previously reported case of this combined injury pattern in a patient with open physes. We present a case of a 12-year-old boy who sustained an ACL-posterolateral corner injury while playing football, and subsequently underwent acute repair of the posterolateral structures with a plan to perform ACL reconstruction at a later date.

Synopsis The anterior cruciate ligament (ACL) is an important stabilizer of the knee against translational and rotational forces. The goal of anatomic reconstruction of the ACL-deficient knee is to re-create a stable knee that will allow for return to sport and prevent recurrent injury. Multiple graft options exist for ACL reconstruction, and each option has unique advantages and disadvantages. With appropriate patient selection, each graft can be utilized to optimize patient outcomes. Allograft options limit morbidity following ACL reconstruction, but care must be taken with surgical technique and postoperative rehabilitation to allow for graft incorporation. An understanding of the surgical technique and differences between graft options will allow the patient, surgeon, and physical therapist to maximize outcomes following ACL reconstruction. Level of Evidence Therapy, level 5. J Orthop Sports Phys Ther 2012;42(3):196–207, Epub 25 January 2012. doi:10.2519/jospt.2012.4083

Background: Evidence suggests that single-bundle anterior cruciate ligament (ACL) reconstruction does not reliably prevent the development of knee osteoarthritis (OA). Purpose: This study was conducted to determine the overall prevalence of and risk factors for the development of radiographic knee OA after single-bundle ACL reconstruction. Study Design: Case control study; Level of evidence, 3. Methods: There were 249 individuals who had undergone primary single-bundle ACL reconstruction included in this retrospective cohort study. Follow-up radiographs were scored by a single orthopaedic surgery sports medicine fellow using the Kellgren-Lawrence (KL) scale to determine the degree of OA in the medial, lateral, and patellofemoral compartments. Radiographic OA of the involved knee was considered to be present if, compared with the noninvolved knee, there was at least a 2-grade difference in the KL score in at least 1 compartment or a 1-grade difference in at least 2 compartments. Predictors of OA that were explored included patient age, sex, body mass index (BMI), smoking status activity level, meniscectomy before or concurrent with ACL reconstruction, chondral injury present at the time of ACL reconstruction, graft type and source, tibial and femoral tunnel positions, need for revision, and length of follow-up. Univariable and stepwise multivariable logistic regressions were used to identify factors that were associated with radiographic knee OA. Results: Thirty-nine percent of the patients had radiographic OA an average of 7.8 years after surgery. Female sex, BMI, time from injury to surgery, medial and patellofemoral compartment chondrosis, prior medial or lateral meniscectomy, concurrent medial meniscectomy, and length of follow-up were associated with radiographic knee OA after ACL surgery. Stepwise multivariable logistic regression indicated that prior medial meniscectomy (95% confidence interval [CI], 1.39-6.85), grade 2 or greater medial chondrosis (95% CI, 1.27-6.73), length of follow-up (95% CI, 1.07-1.24), and BMI (overweight 95% CI, 1.08-3.84; obese 95% CI, 1.34-7.80) were the best set of predictors of knee OA. Conclusion: Despite reduced laxity and instability and improved activity and participation, individuals who have undergone ACL reconstruction are still at high risk for developing knee OA compared with the general population. The strongest predictors of knee OA after ACL reconstruction were obesity and grade 2 or greater chondrosis in the medial compartment. These results may aid in identifying patients at risk for OA after ACL reconstruction.

We performed this study to investigate the therapeutic role of vascular endothelial growth factor (VEGF) in medial collateral ligament (MCL) healing. Murine muscle derived stem cells (MDSCs) obtained via the preplate technique were retrovirally transduced to express: (1) VEGF and nLacZ (MDSC-VEGF), (2) soluble fms-like tyrosine kinase-1 (sFLT1, a VEGF-specific antagonist) and nLacZ (MDSC-sFLT1), and (3) nLacZ (MDSC-nLacZ). After transecting the MCL of immunodeficient rats, 5 × 105 cells of each of the transduction groups list above were transplanted into the MCL injury site. A control group was injected with phosphate-buffered saline (PBS) only. Immunohistochemical staining demonstrated that there were more Isolectin B4 and β-galactosidase double positive cells in the rats transplanted with MDSC-VEGF transduced cells than the other groups at week 1. Capillary density was significantly higher in the MDSC-VEGF group than the other groups at week 2; however, there were no significant differences in the biomechanical assessment between the MDSC-VEGF and MDSC-nLacZ groups. On the other hand, the MDSC-sFLT1 group revealed a lower capillary density than the other two groups and the functional ligament healing of the MDSC-sFLT1 group was significantly decreased compared to the other groups when assessed biomechanically. The findings of the present study suggest that angiogenesis plays a critical role in the healing process of injured MCL. © 2011 Orthopaedic Research Society. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:627–633, 2012

Knee dislocations are relatively rare injuries but necessitate immediate and appropriate management. The prompt reduction of the dislocation and detailed evaluation of the neurovascular status of the limb are required to avoid limb-threatening complications. Although there remains considerable controversy over the ideal management of the multiple-ligamentous injured knee, here we present our preferred approach to the treatment of this injury. Important principles begin with a detailed and specific diagnosis, including the timing, grade, and associated injuries. Next, operative management should be performed only after thorough preoperative planning, timed electively, and performed within an inpatient setting. Although we still operate on complete grade III lateral corner and medial collateral ligament injuries acutely, delayed and/or staged surgery is acceptable in many cases of cruciate reconstruction. Generally speaking, the postoperative rehabilitation and return to work/sports is slower in these patients compared with those undergoing primary anterior cruciate ligament surgery. Nevertheless, adherence to strict surgical principles of anatomic repair/reconstruction of all ligamentous injuries can result in regaining adequate knee function. We present important considerations in surgical indications, timing, graft selections, anatomic reconstruction, and postoperative rehabilitation.

Background High tibial osteotomy is technically demanding. Risks include injury to the popliteal neurovascular bundle. The present goal was to further define this risk. Hypothesis The distance from the posterior tibia to the popliteal artery increases with increasing knee flexion. A saw angle perpendicular to the coronal plane can injure the popliteal artery. Study Design Descriptive laboratory study. Methods Seven fresh-frozen cadaveric lower extremities were used. Lateral radiographs at knee flexion angles of 90°, 60°, 45°, 30°, and 0° were taken to measure the distance from the anterior border of the popliteal artery to the posterior cortex of the tibia 5.0 mm and 2.0 cm below the joint line. After an opening wedge high tibial osteotomy was made, qualitative assessments were made of the depth of a saw blade inserted into the kerf and the relative encroachment of the saw blade on the popliteal artery. The interval through which the space anterior to the popliteus can be accessed was identified by gross dissection in all specimens. Results The distance from the posterior tibia to the popliteal artery increased with knee flexion. At 5.0 mm and 2.0 cm below the joint line, the mean distance at 90° was significantly greater than at all other angles. The popliteal artery could be injured by the oscillating saw at angles greater than 30° to the coronal plane. A protective device inserted anterior to the popliteus protects the neurovascular structures. Conclusion The popliteal artery is farthest from the posterior tibia at 90° of knee flexion. Saw angles greater than 30° from the coronal plane put the popliteal neurovasculature at risk of injury. Clinical Relevance To perform a safe osteotomy, the knee should be positioned in 90° of flexion with the saw angled less than 30° from the coronal plane. A protective device deep to the popliteus may protect against popliteal injury.

Background: Tears of the posterior root of the medial meniscus are becoming increasingly recognized. They can cause rapidly progressive arthritis, yet their biomechanical effects are not understood. The goal of this study was to determine the effects of posterior root tears of the medial meniscus and their repairs on tibiofemoral joint contact pressure and kinematics. Methods: Nine fresh-frozen cadaver knees were used. An axial load of 1000 N was applied with a custom testing jig at each of four knee-flexion angles: 0°, 30°, 60°, and 90°. The knees were otherwise unconstrained. Four conditions were tested: (1) intact, (2) a posterior root tear of the medial meniscus, (3) a repaired posterior root tear, and (4) a total medial meniscectomy. Fuji pressure-sensitive film was used to record the contact pressure and area for each testing condition. Kinematic data were obtained by using a robotic arm to record the position of the knees for each loading condition. Three-dimensional knee kinematics were analyzed with custom programs with use of previously described transformations. The measured variables were axial rotation, varus angulation, lateral translation, and anterior translation. Results: In the medial compartment, a posterior root tear of the medial meniscus caused a 25% increase in peak contact pressure compared with that found in the intact condition (p < 0.001). Repair restored the peak contact pressure to normal. No difference was detected between the peak contact pressure after the total medial meniscectomy and that associated with the root tear. The peak contact pressure in the lateral compartment after the total medial meniscectomy was up to 13% greater than that for all other conditions (p = 0.026). Significant increases in external rotation and lateral tibial translation, compared with the values in the intact knee, were observed in association with the posterior root tear (2.98° and 0.84 mm, respectively) and the meniscectomy (4.45° and 0.80 mm, respectively), and these increases were corrected by the repair. Conclusions: This study demonstrated significant changes in contact pressure and knee joint kinematics due to a posterior root tear of the medial meniscus. Root repair was successful in restoring joint biomechanics to within normal conditions. Clinical Relevance: This study provides a biomechanical rationale for surgical repair of posterior root tears of the medial meniscus. Clinical studies are required to define the appropriate patient population for, and to determine the clinical efficacy of, surgical treatment of this injury.

Purpose The purpose of this study was to identify preoperative and intraoperative factors that predict patient-oriented outcome as measured by the International Knee Documentation Committee (IKDC) Subjective Knee Form after anterior cruciate ligament (ACL) reconstruction. Methods We identified 402 subjects who had undergone primary single-bundle arthroscopic ACL reconstruction at a mean follow-up of 6.3 years (range, 2 to 15 years). The IKDC Subjective Knee Form was used to measure patient-reported outcome and was dichotomized as above or below the patient-specific age- and gender-matched population mean. Potential predictor variables included subject demographics, activity level before surgery, previous meniscectomy, and surgical variables. Multivariate logistic regression analysis was performed to identify the best subset of predictors for determining the likelihood that the IKDC score was better than the age- and gender-matched population mean. Results The dichotomized IKDC score was associated with body mass index (BMI), smoking status, education, previous medial meniscectomy, and medial chondrosis at the time of ACL reconstruction. The multivariate model containing only factors known before surgery included BMI and smoking status. Subjects with a BMI greater than 30 kg/m 2 had 0.35 times the odds of success as subjects with a normal BMI. Subjects who smoked had 0.36 times the odds of success as subjects who did not smoke. A model including medial chondrosis at the time of surgery had a slightly higher discriminatory power (area under the receiver operating characteristic curve, 0.65 v 0.61) and negative predictive value (71.4% v 60.0%) but similar positive predictive power (86.3% v 85.9%). Conclusions Lower patient-reported outcome after ACL reconstruction was strongly associated with obesity, smoking, and severe chondrosis at the time of surgery. Level of Evidence Level III, prognostic case-control study.