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Peroneal nerve injuries are rare injuries and usually associated with multiligamentous knee injuries (MLKIs) involving one or both cruciate ligaments. The purpose of our study was to perform a multicenter retrospective cohort analysis to examine the rates of peroneal nerve injuries and to see whether a peroneal nerve injury was suggestive of a particular injury pattern.A retrospective chart review was conducted in patients who were diagnosed with MLKI at two level I trauma centers from January 2001 to March 2021. MLKIs were defined as complete injuries to two or more knee ligaments that required surgical reconstruction or repair. Peroneal nerve injury was clinically diagnosed in these patients by the attending orthopaedic surgeon. Radiographs, advanced imaging, and surgical characteristics were obtained through a chart review.Overall, 221 patients were included in this study. The mean age was 35.9 years, and 72.9% of the population was male. Overall, the incidence of clinical peroneal nerve injury was 19.5% (43 patients). One hundred percent of the patients with peroneal nerve injury had a posterolateral corner injury. Among patients with peroneal nerve injury, 95.3% had a complete anterior cruciate ligament (ACL) rupture as compared with 4.7% of the patients who presented with an intact ACL. There was 4.4 times of greater relative risk of peroneal nerve injury in the MLKI with ACL tear group compared with the MLKI without an ACL tear group. No statistical difference was observed in age, sex, or body mass index between patients experiencing peroneal nerve injuries and those who did not.The rate of ACL involvement in patients presenting with a traumatic peroneal nerve palsy is exceptionally high, whereas the chance of having a spared ACL is exceptionally low. More than 90% of the patients presenting with a nerve palsy will have sustained, at the least, an ACL and posterolateral corner injury.IV, Case Series.

Postoperative protocols after surgical treatment of calcaneal fracture have not been standardized to date. There are only a few reports on the efficacy of heel-unloading orthoses (HUOs; Mars shoe, Graffin orthosis), and thier efficacy is uncertain.The purpose of this study was to compare postoperative radiologic and clinical outcomes in patients with calcaneal fractures who used Graffin orthosis.Multicenter retrospective study.We finally extracted 182 patients from a database of the Trauma Research Group of Nagoya and divided them into two groups: group C (underwent casting or splinting only) and group O (Graffin orthosis was used). A propensity score algorithm was used to match group C to group O in a 1:1 ratio. We evaluated American Orthopaedic Foot and Ankle Society (AOFAS) score at three and six months after surgery and at final follow-up. Differences in reduction of the Böhler angle between the two groups were evaluated radiographically. All data were analyzed with a t-test or Fisher's exact test. P.05 was considered statistically significant.The AOFAS score 3 months after surgery in group O was significantly higher than that in group C (69.57 vs. 77.22; P = .004). However, there were no statistically significant differences between group C vs. group O in AOFAS scores at 6 months after surgery and at final follow-up (81.92 vs. 85.67 and 89.18 vs. 88.13; P = .087 and 0.597, respectively). There was no significant statistical difference in the reduction of the Böhler angle (5.07 vs. 5.89; P = .529).At 3 months postoperatively, the orthosis group showed predominantly better functional results. We believe that heel-unloading orthoses are useful for patients who require an early return to work and to daily life.

Prophylactic knee braces (PKBs) are widely used by athletes in pivoting and landing sports and have the potential to influence knee movement and alignment, thus modulating anterior cruciate ligament (ACL) injury risk. This systematic review analyses current evidence on the biomechanical effects that PKBs have in the prevention of ACL injuries.The review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Searches were conducted on PubMed, Web of Science, Scopus, Ovid MEDLINE, EMBASE, Cochrane, and CINAHL for studies published from inception until May 31, 2021. Included studies assessed the effects of PKBs on biomechanical variables associated with ACL injuries in landing or pivoting tasks, comparing between braced and unbraced conditions.A total of 234 articles were identified; from which, 14 controlled, laboratory, biomechanical studies were included in this review. The effects of PKBs on knee biomechanics could be divided into kinematic variables in the coronal, sagittal, and transverse planes; and common kinetic variables, such as ground reaction force (GRF) and ACL load/strain. Also, PKBs were found to have protective effects in coronal and transverse plane kinematics, but results in the sagittal plane were inconclusive. Assessing knee kinetics, PKBs were advantageous in decreasing ACL load/strain but had no significant effect on GRF.Prophylactic knee braces may serve to reduce ACL injury risk by modulating knee coronal and transverse plane movements and ACL load/strain during high-risk maneuvres. Precise recommendations are limited by study heterogeneity. More prospective studies are needed to assess ACL injury risk during high-risk sports using specific PKBs.

BACKGROUND: The Knee Injury and Osteoarthritis Outcome Score (KOOS) is well known and commonly used to assess young, active patients with ACL injuries. However, this application of the outcome measure has been called into question. There is currently no evidence supporting the structural validity of the KOOS for this patient population. Structural validity refers to whether a questionnaire meant to provide scores on different subscales behaves as intended in the populations of interest. Structural validity should be assessed for all questionnaire measures with multiple items or subscales. QUESTIONS/PURPOSES: Does the KOOS demonstrate adequate structural validity in young, active patients with ACL tears, when evaluated using (1) exploratory and (2) confirmatory factor analyses? METHODS: Between January 2014 and March 2017, 1033 patients were screened for eligibility in the Stability 1 randomized controlled trial from nine centers in Canada and Europe. Patients were eligible if they had an ACL deficient knee, were between 14 and 25 years old, and were thought to be at higher risk of reinjury based on the presence of two or more of the following factors: participation in pivoting sports, presence of a Grade 2 pivot shift or greater, generalized ligamentous laxity (Beighton score of 4 or greater), or genu recurvatum greater than 10°. Based on this criteria, 367 patients were ineligible and another 48 declined to participate. In total, 618 patients were randomized into the trial. Of the trial participants, 98% (605 of 618) of patients had complete baseline KOOS questionnaire data available for this analysis. Based on study inclusion criteria, the baseline KOOS data from the Stability 1 trial represents an appropriate sample to investigate the structural validity of the KOOS, specifically for the young, active ACL deficient population. A cross sectional retrospective secondary data analysis of the Stability 1 baseline KOOS data was completed to assess the structural validity of the KOOS using exploratory and confirmatory factor analyses. Exploratory factor analysis investigates how all questionnaire items group together based on their conceptual similarity in a specific sample. Confirmatory factor analysis is similar but used often in a second stage to test and confirm a proposed structure of the subscales. These methods were used to assess the established five-factor structure of the KOOS (symptoms [seven items], pain [nine items], activities of daily living [17 items], sport and recreation [five items], and quality of life [four items]) in young active patients with ACL tears. Incremental posthoc modifications, such as correlating questionnaire items or moving items to different subscales, were made to the model structure until adequate fit was achieved. Model fit was assessed using chi-square, root mean square error of approximation (RMSEA) and an associated 90% confidence interval, comparative fit index (CFI), Tucker-Lewis index (TLI), as well as standardized root mean square residual (SRMR). Adequate fit was defined as a CFI and TLI > 0.9, and RMSEA and SRMR < 0.08. RESULTS: Structural validity of the KOOS was not confirmed when evaluated using (1) exploratory or (2) confirmatory factor analyses. The exploratory factor analysis, where the 42 KOOS items were allowed to group naturally, did not reflect adequate fit for a five-factor model (TLI = 0.828). Similarly, the confirmatory factor analysis used to investigate the KOOS structure as it was originally developed, revealed inadequate fit in our sample (RMSEA = 0.088 [90% CI 0.086 to 0.091]). Our analysis suggested a modified four-factor structure may be more appropriate in young, active ACL deficient patients; however, the final version presented here is not appropriate for clinical use because of the number and nature of post-hoc modifications required to reach adequate fit indices. CONCLUSION: The established five-factor structure of the KOOS did not hold true in our sample of young, active patients undergoing ACL reconstruction, indicating poor structural validity. CLINICAL RELEVANCE: We question the utility and interpretability of KOOS subscale scores for young, active patients with ACL tears with the current form of the KOOS. A modified version of the KOOS, adjusted for this patient population, is needed to better reflect and interpret the outcomes and recovery trajectory in this high-functioning group. A separate analysis with a defined a priori development plan would be needed to create a valid alternative.

Knee overload was detrimental to knee osteoarthritis subjects. We aim to analyze the association between the subchondral bone microarchitecture sclerosis and typical knee-straining activities.The frequency of experiencing squatting, kneeling, lifting, and climbing of 481 knee osteoarthritis subjects was investigated. Subchondral bone microarchitecture (bone volume fraction, trabecular thickness, trabecular separation, and trabecular number) was measured by the fast imaging with steady-state free precession magnetic resonance imaging applying trabecular sequencing, at baseline and 12-mo follow-up. Logistic regression was conducted to investigate the relationship between microarchitecture change and each knee-straining activity, adjusted by age, sex, weight, and Kellgren-Lawrence grade. All data were from the Osteoarthritis Initiative.Long kneeling was associated with increased bone volume fraction (adjusted odds ratio = 1.16, confidence interval = 1.01-1.33) and trabecular number (adjusted odds ratio = 1.16, confidence interval = 1.02-1.33). Long squatting was associated with a lower risk of increased trabecular separation (adjusted odds ratio = 0.84, confidence interval = 0.71-0.98) and a higher risk of increased trabecular thickness (adjusted odds ratio = 1.29, confidence interval = 1.06-1.55). Long squatting also increased the medial compartment joint width narrowing (-0.21 in squatting group vs -0.03 in no squatting group, P0.05).Knee osteoarthritis patients should avoid long squatting and kneeling, and subchondral bone microarchitecture possesses excellent potential as a monitoring indicator in subjects who kneel or squat for long.

Articular cartilage injuries of the knee are being observed with increasing frequency in athletes and have proven to be difficult to treat given the limited regenerative ability of cartilage and the potential for progressive joint degeneration. A wide range of surgical treatments such as microfracture, autologous chondrocyte implantation, and osteochondral autograft and allograft have demonstrated promising results in these high-demand individuals. These procedures permit healing of cartilage defects while decreasing pain and restoring function with patient-reported outcomes demonstrating significant improvement at short-, mid-, and long-term follow-up. Most athletes are able to return to play after cartilage restoration of the knee, regardless of the surgical technique used. Although there is a large degree of heterogeneity across the literature and no consensus as to the optimal technique, osteochondral autograft transfer seems to offer the highest rate of return to sport and return to play at preinjury level. However, autologous chondrocyte implantation and osteochondral allograft transplantation are often used for larger defects or salvage after previous procedures, so results may be confounded. In addition, a multitude of factors including patient history, characteristics of the chondral lesion, and postoperative management may affect functional outcomes in athletes.

Background Segond fractures (avulsion fractures of the proximal lateral tibia) are highly associated with anterior cruciate ligament (ACL) tears in adult patients. This large case series of pediatric Segond fractures describes the associated intra-articular knee injuries to determine if these fractures have a high incidence of ACL tears or its equivalent injury in young patients. Methods Institutional review board approved retrospective study at a tertiary children's hospital of patients under 19 years who were diagnosed with a Segond fracture between 2009 and 2019 was conducted. Demographics, clinical data, imaging features, associated injuries, and treatment information were collected. Results Fifty-three patients (44 males and 9 females) with median age 15.4 (11.8 to 19) years with Segond fractures of the proximal tibia on radiographic imaging were included. Diagnosis of associated injuries was established based on clinical examination, radiology report, and arthroscopic findings. Median Segond fracture size was 2.0×9.0 mm measured on standard anteroposterior knee radiographs. Magnetic resonance imaging (MRI) was obtained in 49/53 (92.5%) patients. Associated injuries included ACL tears (39 patients, 73.6%), tibial spine fractures (9, 17.0%), and other injuries (5, 9.4%). 37/53 (69.8%) patients had meniscal injury. Three (5.7%) patients sustained multiligament injuries. All associated injuries were confirmed by either MRI/computerized tomography or direct operative examination. Among Segond fractures found with ACL tears, 12 (30.8%) were contact injuries, 30 (76.9%) were sports injuries. In associated tibial spine fractures, 7 (78%) injuries were contact in nature and were sports related. There was a statistically significant difference (P=0.013) in age, patients with tibial spine fractures (median 13.6 y) being younger than those with ACL tears (median 15.4 y). 12/53 (22.6%) had associated articular cartilaginous injuries, 3 of which were treated surgically. Overall, 81.1% of patients were treated operatively for associated intra-articular injuries. Conclusions This large case series of Pediatric Segond fractures suggests a high association with intra-articular injuries, specifically, ACL tears and its equivalent injury, that is, tibial spine fractures, the later more common in the younger patient population. An MRI is recommended in patients with a Segond fracture for characterizing the exact intra-articular injury to help plan the appropriate management. Level of evidence Level IV-prognostic.

This article was updated on May 19, 2021 because of previous errors, which were discovered after the preliminary version of the article was posted online. In the legend for Figure 3-A, the phrase that had read "T1-weighted coronal MRI showing a right knee" now reads "T1-weighted coronal MRI showing a left knee." On page 924, in the section entitled "Materials and Methods," the sentence that had read "If there was no radiographic evidence or if there was a clinical note that documented visible deformity around the knee with no reduction maneuver being performed, then the patient was classified into the non-dislocated MLKI group." now reads "If there was no radiographic evidence or if there was no clinical note that documented visible deformity around the knee with no reduction maneuver being performed, then the patient was classified into the non-dislocated MLKI group." On page 925, in the section entitled "Analysis," the sentence that had read "Our study included 78 dislocated MLKIs and non-dislocated MLKIs, so both cohorts were adequately powered for the overall analysis." now reads "Our study included 45 dislocated MLKIs and 78 non-dislocated MLKIs, so both cohorts were adequately powered for the overall analysis." Finally, on page 927, in the section entitled "Discussion," the sentence that had read "Interestingly, we found that MLKIs with a documented knee dislocation had a substantially higher rate of vascular injury (23%) compared with those without (3%)." now reads "Interestingly, we found that MLKIs with a documented knee dislocation had a substantially higher rate of vascular injury (18%) compared with those without (4%)."The terms “knee dislocation” and “multiligamentous knee injury” (MLKI) have been used interchangeably in the literature, and MLKI without a documented knee dislocation has often been described as a knee dislocation that “spontaneously reduced.” We hypothesized that MLKI with documented tibiofemoral dislocation represents a more severe injury than MLKI without documented dislocation. We aimed to better characterize the injuries associated with documented knee dislocations versus MLKIs without evidence of tibiofemoral dislocation. A total of 124 patients who were treated for an MLKI or knee dislocation to a single level-I trauma center between January 2001 and January 2020 were retrospectively reviewed. Patients were stratified into 2 groups, those with and those without a documented knee dislocation, and 123 of 124 patients were included in the analysis (78 in the non-dislocated group and 45 in the dislocated group). Data regarding patient demographics, injury pattern, and associated neurovascular injury were collected and compared between groups. Dislocated MLKIs, compared with non-dislocated MLKIs, had higher rates of peroneal nerve injury (38% versus 14%, respectively; p = 0.004), vascular injury (18% versus 4%; p = 0.018), and an increased number of medial-sided injuries (53% versus 30%; p = 0.009). There was no difference between dislocated and non-dislocated MLKIs in the number of bicruciate ligament injuries (82% versus 77%, respectively; p = 0.448), or lateral-sided injuries (73% versus 74%; p = 0.901). Dislocated MLKIs were found to have increased rates of neurovascular injury compared with non-dislocated MLKIs, suggesting that knee dislocation and MLKI may not be synonymous in terms of associated injuries. Not all MLKIs are the result of a knee dislocation, and thus a documented tibiofemoral dislocation is a distinct entity that carries a greater risk of neurovascular compromise. We propose that these terms not be used interchangeably as previously described, and also that a high degree of vigilance must be maintained to evaluate for potential limb-threatening neurovascular injuries in any type of MLKI. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND Multiligamentous knee injuries (MLKIs) are rare, and heterogeneous in presentation and treatment options. Consequently, optimal postoperative rehabilitation of MLKI remains unclear. OBJECTIVE To summarize the latest evidence for postoperative rehabilitation protocols following multiligamentous knee reconstruction (MLKR). PATIENTS AND METHODS A multidatabase search was conducted with the aid of a health sciences librarian. Blinded reviewers conducted multiple screenings of studies evaluating postoperative rehabilitation protocols following MLKR. All included studies were then graded based on level of evidence, and data concerning patient demographics and rehabilitation protocols were extracted. RESULTS MLKR rehabilitation protocols differ widely in terms of weightbearing, bracing, initiation, and types of physical therapy, yet several established protocols were referenced frequently throughout the literature. Such protocols resulted in good outcomes, with patients returning to running in 6 to 12 months and returning to sport in 8 to 12 months. CONCLUSION The rare nature of MLKI hinders the ability to create a standardized rehabilitation protocol. However, early postoperative physical therapy and range of motion consistently lead to improved outcomes. Randomized studies are needed to determine optimal postoperative rehabilitation following MLKR.

Effective options exist for acute nonoperative management of anterior tibial spine fractures, yet there exists a paucity of literature describing long-term outcomes for these patients. This systematic review thus aims to consolidate management strategies and complications for patients with nonoperative anterior tibial spine fractures. In accordance with PRISMA guidelines, 5 databases (CINAHL, MEDLINE, EMBASE, Cochrane, and Pubmed) were searched and screened in duplicate. Quality assessment was performed using the Methodological Index for Non-Randomized Studies (MINORS) criteria. Of 485 studies identified in the initial search, a total of 18 studies involving 369 patients were eligible for this review. These were stratified into 173 type I, 124 type II, and 72 type III injuries as described by Meyers and McKeever. All patients were treated with knee immobilization in either full extension or slight flexion, with possible closed reduction and/or aspiration of hemarthrosis. Complications at final follow-up comprised 33.9% of patients with persistent stiffness, 19.4% persistent instability, 11.1% mechanical symptoms, 6.37 delayed anterior cruciate ligament reconstruction, 4.9% delayed operative intervention for other complications, and 1.9% extension impingement. Given the lack of comparative studies in this review, definitive conclusions for nonoperative management are difficult to establish on the basis of the current body of literature alone. A modestly higher rate of arthrofibrosis and persistent laxity are seen in higher-grade injuries, however, only a minority of studies stratified complications by Meyers and McKeever classification in this review. A better understanding of variables in treatment decision making require further prospective study focused on the collection of functional and patient-reported outcome measures, whereas also further delineating complications by injury severity.

OBJECTIVES To evaluate the functional outcomes of patients with displaced patellar fractures treated with anterior plate constructs. DESIGN Prospective cohort and retrospective clinical and radiographic assessment. SETTING Level I Trauma Center. PATIENTS/PARTICIPANTS Between 2014 and 2018, 18 patients who underwent operative intervention for an isolated, displaced patella fracture (OTA/AO 34C1-3) with a minimum of 1-year follow-up agreed to participate in the study. The mean follow-up was 19.5 ± 6.0 months. INTERVENTION Patients were treated with 2.4 or 2.7-mm plates and supplemental screws or cerclage wires. MAIN OUTCOME MEASUREMENTS Patients were evaluated with the Short Form-36 Survey and the Knee Injury and Osteoarthritis Outcome Scores and asked about symptomatic implants. The range of motion was assessed by goniometer. RESULTS The cohort had no wound complications, infections, nonunion, loss of reduction, or implant failure. Active knee flexion was 131 ± 7 degrees. Five patients (28%) endorsed implant irritation. Only one patient (5.5%) underwent implant removal, which consisted of transverse screw removal alone. Twelve of the 14 patients (86%), who were previously employed, returned to work at 10 ± 7 weeks. All Knee Injury and Osteoarthritis Outcome Scores subscale scores and the Short Form-36 Survey scores for physical functioning, limitations due to physical health, limitations due to mental health, and social functioning were significantly lower than reference population norms (P < 0.05). CONCLUSIONS Anterior plating provides reliable fixation for displaced patellar fractures and results in a low incidence of implant irritation. However, patients who had anterior fixation for displaced patella fractures continue to exhibit functional deficits at 1-year postoperatively. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

OBJECTIVES: To determine the feasibility and performance of a deep learning system (DLS) used to create synthetic artificial intelligence-based fat-suppressed (FS) MR images (AFSMRI) of the knee. MATERIALS AND METHODS: This single-center study was approved by the Institutional Review Board. Artificial intelligence-based fat-suppressed MR images were created from non-FS images using a deep learning system with a modified Convolutional Neural Networks-based U-Net that employed a training set of 25,920 images and validation set of 16,416 images. Three musculoskeletal radiologists reviewed 88 knee MR studies in two sessions, the original (proton density (PD) + FSPD) and the synthetic (PD + AFSMRI). Readers recorded AFSMRI quality (diagnostic/non-diagnostic), and the presence or absence of meniscal, ligament and tendon tears, cartilage defects, and bone marrow abnormalities. Contrast-to-noise (CNR) measurements were made between subcutaneous fat, fluid, bone marrow, cartilage, and muscle. The original MR imaging sequences were used as the reference standard to determine the diagnostic performance of AFSMRI (combined with the original PD sequence). This is a fully balanced study design, where all readers read all images the same number of times, which allowed the determination of the interchangeability of the original and synthetic protocols. Descriptive statistics, intermethod agreement, interobserver concordance, and interchangeability tests were applied. A p value < 0.01 was considered statistically significant for the likelihood ratio testing, and p value 0.05), except for cartilage assessment. Interobserver agreement ranged from moderate to substantial for almost all evaluated structures. Original and synthetic protocols were interchangeable for the diagnosis of all evaluated structures. There was no significant difference for the common exact match proportions for all combinations (p> 0.01). The conspicuity of all tissues assessed through CNR was higher on AFSMRI than on original FSPD images (P

Late rupture of the posterior cruciate ligament (PCL) in cruciate-retaining total knee arthroplasty (TKA) can lead to increased AP instability. This results in increased stress on the medial hamstrings resulting in hamstring-based pain. We looked to identify patients with late PCL failure using a lateral stress radiograph.A prospective cohort analysis was completed at a single institution. Eligible patients were divided into two groups based on the amount of anterior knee pain. Pain was defined as a visual analog scale of greater than or equal to 3. Each group completed a visual analog scale, Knee Injury and Osteoarthritis Outcome Score Junior, Patient-Reported Outcome Measurement Information System score and underwent a lateral posterior stress/nonstress radiograph. Amount of posterior translation and posterior tibial slope was measured.Patients who had painful TKAs at the follow-up had lower Knee Injury and Osteoarthritis Outcome Score Junior (45.86 ± 13.52 versus 78.00 ± 13.26 P0.001). Those patients were also found to have significantly higher posterior tibial translation with stress radiograph (6.89 ± 1.874 versus 3.91 ± 2.15 mm P0.001) and significantly increased tibial slope (6.51 ± 2.37° versus 3.98 ± 1.79°, P = 0.004). Seven of the 14 patients in the pain group underwent revision surgery, with 6 patients found to have incompetent PCLs.Patients with increased AP translation and increased posterior tibial slope after cruciate-retaining TKA are likely to have worse pain and outcome measures.

BACKGROUND Due to the pain caused by knee injuries, low-load resistance training with blood flow restriction (L-BFR) may be a potential adjuvant therapeutic tool in the rehabilitation of knee injuries. This review aimed to analyze the effectiveness of L-BFR training modality in knee rehabilitation. DESIGN A meta-analysis was conducted to determine the potential impact of blood flow restriction on patients with knee injuries. PubMed, EBSCO, and Web of Science databases were searched for eligible studies from January 2000 until January 2020. The mean differences of the data were analyzed using Revman 5.3 software with a 95% confidence interval. RESULTS Nine studies fulfilled the inclusion criteria. These studies involved 179 patients who received L-BFR, 96 patients who underwent high-load resistance training, and another 94 patients who underwent low-load resistance training. The analysis of pooled data showed that patients in both the L-BFR (standardized mean difference, 0.83 [0.53, 1.14], P < 0.01) and high-load resistance training (standardized mean difference, -0.09 [-0.43, 0.24], P = 0.58) groups experienced an increase in muscle strength after the training. In addition, pain score was significantly reduced in the L-BFR group compared with the other two groups (standardized mean difference, -0.61 [-1.19, -0.03], P = 0.04). CONCLUSIONS Muscle strength increased after L-BFR and high-load resistance training compared with low-load resistance training. Furthermore, pain score was significantly reduced after L-BFR. Hence, L-BFR is a potential intervention to be applied in rehabilitation of knee injuries.

BACKGROUND Increased enrollment in government-based insurance plans has been reported. With youth sports injuries on the rise, increased ordering of advanced imaging such as magnetic resonance imaging (MRI) has occurred. This study sought to report on the impact of insurance type on access to and results of knee MRI in pediatric sports medicine patients. METHODS A retrospective review of 178 consecutive pediatric sports medicine clinics was completed. INCLUSION CRITERIA patients younger than 18 years, routine knee MRI ordered, sports medicine diagnosis, and insurance. Data included basic demographics, injury date, date and location (urgent care vs. clinic) of the first presentation, details of MRI ordering and approval, date and location of MRI follow-up, MRI results (negative, minor findings, major findings), and eventual treatment required. RESULTS A total of 168 charts underwent a complete review. The patients' average age was 14±3 years and 54% (N=90) were female. Ninety-eight had government insurance and 70 had commercial insurance. The time between injury and MRI completion was significantly longer with government insurance (34 vs. 67 d, P

Cartilage injuries in the knee are common and can occur in isolation or in combination with limb malalignment, meniscus, ligament, and bone deficiencies. Each of these problems must be addressed to achieve a successful outcome for any cartilage restoration procedure. If nonsurgical management fails, surgical treatment is largely based on the size and location of the cartilage defect. Preservation of the patient's native cartilage is preferred if an osteochondral fragment can be salvaged. Chondroplasty and osteochondral autograft transfer are typically used to treat small (

The traumatic knee dislocation (KD) is a complex condition resulting in injury to >1 ligament or ligament complexes about the knee, termed multiligament knee injuries. Typically, KDs result in injury to both cruciate ligaments with variable injury to collateral ligament complexes. Very rarely, KD may occur with single cruciate injuries combined with collateral involvement but it is important to understand that not all multiligament knee injuries are KDs. Patients can present in a wide spectrum of severity; from frank dislocation of the tibiofemoral joint to a spontaneously reduced KD, either with or without neurovascular injury. The initial evaluation of these injuries should include a thorough patient history and physical examination, with particularly close attention to vascular status which has the most immediate treatment implications. Multiple classification systems have been developed for KDs, with the anatomic classification having the most practical application.

An understanding of knee ligament anatomy and biomechanics is foundational for physicians treating knee injuries, especially the more rare and morbid multiligamentous knee injuries. This chapter examines the roles that the cruciate and collateral anatomy and morphology play in their kinematics. Additionally, the biomechanics of the ACL, PCL, MCL, and LCL are discussed as they have surgical and reconstructive implications.

Meniscal root tears are an increasingly recognized injury leading to notable functional limitations, potential rapid cartilage deterioration of the affected compartment, and subsequent risk of total knee arthroplasty if left untreated. Repair of these tears is advised when articular cartilage remains intact because both medial and lateral meniscus root repairs have demonstrated favorable results. Recent literature demonstrates decreased rates of osteoarthritis and arthroplasty after medial meniscus root repair compared with partial meniscectomy and nonsurgical management. The transtibial pull-out repair technique is most commonly used and provides a biomechanically strong suture construct with standard and familiar knee arthroscopy portals. Furthermore, repair has recently been shown to be economically effective by decreasing overall societal healthcare costs when compared with more conservative management strategies. This review outlines the evaluation, treatment, and documented outcomes of meniscal root repair, which is imperative to the preservation of knee function and maintaining quality of life.

Introduction The purpose of this study was to compare leg, sagittal plane knee and ankle, and frontal plane ankle stiffness over the course of a prolonged treadmill run in neutral and stability footwear. Methods Thirteen male habitual rearfoot runners completed two biomechanical testing sessions in which they ran for 21 min at their preferred running speed in a neutral shoe, then changed either into the same neutral shoe or a stability shoe and ran a further 21 min on a force-instrumented treadmill. Three-dimensional kinematics and kinetics were recorded at the beginning and end of each 21-min interval. Results No differences were observed in leg stiffness between footwear conditions throughout the run (P > 0.05). Knee stiffness increased during the first 21 min (P = 0.009), whereas ankle stiffness reduced at minute 21 (P = 0.004) and minute 44 (P = 0.006). These changes were modulated by an increase in ankle joint compliance and knee joint moments. No differences were observed between footwear conditions for leg and sagittal plane lower extremity joint stiffness (P > 0.05). During the second half of the run, frontal plane ankle stiffness increased in the stability shoe but decreased in the neutral shoe (P = 0.019), attributed to reduced eversion range of motion caused by the added medial post. Conclusions These results suggest that over the course of a prolonged treadmill run, shock attenuation strategies change, which may affect the knee joint.

BACKGROUND Spontaneous osteonecrosis of the knee has recently been termed subchondral insufficiency fracture of the knee (SIFK) to appropriately recognize the etiology of mechanical overloading of the subchondral bone. The purpose of this study was to assess clinical outcomes of SIFK based on progression to surgical treatment and arthroplasty, and to evaluate the risk factors that increase the progression to arthroplasty. METHODS A retrospective review was performed on patients with a diagnosis of SIFK, as confirmed with use of magnetic resonance images (MRIs). Baseline and final radiographs were reviewed. Baseline MRIs were also reviewed for injury characteristics. Failure was defined as progression to surgical treatment or conversion to arthroplasty. RESULTS Two hundred twenty-three patients (71% female) with a mean age of 65.1 years were included. SIFK affected 154 femora (69%) and 123 tibiae (55%), with medial compartment involvement in 198 knees (89%); 74% of medial menisci had root or radial tears, with a mean extrusion of 3.6 mm. Varus malalignment was identified in 54 (69%) of 78 knees. Seventy-six (34%) of all patients progressed to surgical intervention at 2.7 years, and 66 (30%) underwent arthroplasty at 3.0 years. The rates of conversion to surgical intervention and arthroplasty increased to 47% (37 of 79; p = 0.04) and 37% (29 of 79; p = 0.09), respectively, in patients with >5 years of follow-up. The 10-year survival rate free of arthroplasty for patients with SIFK on the medial femoral condyle (p < 0.01), SIFK on the medial tibial plateau (p < 0.01), medial meniscal extrusion (p = 0.01), varus alignment (p = 0.02), and older age (per year older; p = 0.003) was significantly higher than the survival rates of those without each respective condition. CONCLUSIONS Subchondral insufficiency fractures predominantly involve the medial compartment of the knee and commonly present with medial meniscal root and radial tears. Approximately one-third of patients progressed to total knee arthroplasty. Baseline arthritis, older age, location of the insufficiency fracture on both the medial femoral condyle and medial tibial plateau, meniscal extrusion, and varus malalignment were all associated with progression to arthroplasty. LEVEL OF EVIDENCE Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

OBJECTIVE To determine the relationship between patient-reported outcomes (PROs) to the single-leg step-down test (SLSD) and the Y-balance anterior reach (YB-A) 6 months after primary anterior cruciate ligament reconstruction (ACLR). DESIGN Cross-sectional. SETTING Laboratory. PARTICIPANTS Sixty-six patients 6 months after ACLR participated. INTERVENTIONS Patients performed the SLSD, YB-A, and completed PROs after ACLR. MAIN OUTCOME MEASURES Patients completed the International Knee Documentation Committee Score (IKDC), the Lysholm Activity Scale, the Tampa Scale of Kinesiophobia (TSK-11), and the Knee Injury and Osteoarthritis Outcome Score (KOOS)-Symptom, -Sport, and -Quality of Life (QOL) subscales. The SLSD requires subjects to complete as many single-leg step-downs as possible in 60 seconds, and the YB-A involves reaching anteriorly on a single limb. Pearson product moment correlations were used to assess relationships between the YB-A and SLSD performance to each PRO. RESULTS Single-leg step-down test symmetry was significantly correlated with the TSK-11 (r = -0.70), KOOS-Sport (r = 0.40), -Symptom (r = 0.46), and -QOL (r = 0.42). The YB-A symmetry was significantly correlated with the KOOS-Symptom (r = 0.30) and KOOS-Sport (r = 0.30). CONCLUSIONS Single-leg step-down test performance demonstrated stronger relationships to patient-reported knee function than the YB-A. Furthermore, the SLSD symmetry was strongly correlated with fear of movement. The SLSD provides a robust method for clinicians to assess dynamic knee function and may aid in identifying patients who could benefit from intervention to reduce fear of movement or reinjury.

A 31-year-old man who had a chronic popliteus avulsion fracture 18 years earlier treated with physical therapy presented with new onset left knee locking after exercising at the gym. Magnetic resonance imaging demonstrated a chronic popliteus avulsion fracture of the lateral femoral condyle. Surgical excision of the nonunited bone fragment was performed.Isolated popliteus avulsion fractures are extremely rare injuries that occur primarily in a skeletally immature patient population and for which treatment options are not well understood. Treatment options include conservative management and early surgical intervention, both of which have inherent risks and benefits. We recommend prompt imaging with computed tomography (CT) to better characterize the degree of injury and follow-up CT imaging in patients who do not undergo early surgical intervention.

Double-layered menisci are a rare anatomical variant, with cases identified predominantly in Asian populations. We present a case of Caucasian woman with a double-layered lateral meniscus, in which the accessory lateral meniscus had displaced into the intercondylar notch causing feelings of instability within the right knee. The accessory lateral meniscus was removed through arthroscopic surgery, and the patient had complete resolution of her symptoms postoperatively.Double-layered menisci can present similar to bucket-handled meniscus tears if the accessory meniscus displaces into the intercondylar notch. Arthroscopic debridement can be effective at improving clinical symptoms for these patients.

A 13-year-old male American football player sustained an isolated grade III lateral collateral ligament (LCL) rupture and underwent direct repair with biceps femoris rotation graft augmentation after failure of nonoperative management. The procedure was performed without any complications or graft site morbidity and achieved complete functional resolution.Isolated LCL injuries in the pediatric population are an extremely rare finding, with no evidence of rotation graft in the literature to date. Most of these cases involve multiligamentous knee injuries in the adult population, and therefore, there is no consensus regarding pediatric repair vs. reconstruction in this presentation.

We report a very rare case of simultaneous ipsilateral floating hip and floating knee (SIFHFK) injury with the neck of the femur and patella fracture and hip dislocation associated with sciatic nerve injury in a 45-year-old man after a road traffic accident. We adopted a staged approach for surgical fixation of the fractures after stabilization. At the latest 2 years follow-up, the patient was asymptomatic with satisfactory clinical outcome.SIFHFK injuries present a challenging and emergent clinical scenario and require extensive clinical experience, careful planning, and multidisciplinary teamwork because of the paucity of specific treatment protocols for the treatment of this complex injury.

Characteristic injury patterns have been described in pedestrians struck by motor vehicles. The common injury pattern seen in upright pedestrians consists of a triad of head, pelvis, and lower extremity trauma. There are several factors such as vehicular type, design, mass and speed, and impact surfaces that influence the type and distribution of these injuries. We report a case that illustrates the importance of examination of the knee at autopsy when the typical lower extremity diaphyseal fractures that are usually seen in a motor vehicle-pedestrian collision are absent.

Background: The purpose of this investigation was to compare the magnitude of rotatory knee laxity in patients with a partial anterior cruciate ligament (ACL) tear, those with a complete ACL tear, and those who had undergone a failed ACL reconstruction. It was hypothesized that rotatory knee laxity would increase with increasing injury grade, with knees with partial ACL tears demonstrating the lowest rotatory laxity and knees that had undergone failed ACL reconstruction demonstrating the highest rotatory laxity. Methods: A prospective multicenter study cohort of 354 patients who had undergone ACL reconstruction between 2012 and 2018 was examined. All patients had both injured and contralateral healthy knees evaluated using standardized, preoperative quantitative pivot shift testing, determined by a validated, image-based tablet software application and a surface-mounted accelerometer. Quantitative pivot shift was compared with the contralateral healthy knee in 20 patients with partial ACL tears, 257 patients with complete ACL tears, and 27 patients who had undergone a failed ACL reconstruction. Comparisons were made using 1-way analysis of variance (ANOVA) with post hoc 2-sample t tests with Bonferroni correction. Significance was set at p < 0.05. Results: There were stepwise increases in side-to-side differences in quantitative pivot shift in terms of lateral knee compartment translation for patients with partial ACL tears (mean [and standard deviation], 1.4 ± 1.5 mm), those with complete ACL tears (2.5 ± 2.1 mm), and those who had undergone failed ACL reconstruction (3.3 ± 1.9 mm) (p = 0.01) and increases in terms of lateral compartment acceleration for patients with partial ACL tears (0.7 ± 1.4 m/s2), those with complete ACL tears (2.3 ± 3.1 m/s2), and those who had undergone failed ACL reconstruction (2.4 ± 5.5 m/s2) (p = 0.01). A significant difference in lateral knee compartment translation was found when comparing patients with partial ACL tears and those with complete ACL tears (1.2 ± 2.1 mm [95% confidence interval (CI), 0.2 to 2.1 mm]; p = 0.02) and patients with partial ACL tears and those who had undergone failed ACL reconstruction (1.9 ± 1.7 mm [95% CI, 0.8 to 2.9 mm]; p = 0.001), but not when comparing patients with complete ACL tears and those who had undergone failed ACL reconstruction (0.8 ± 2.1 [95% CI, −0.1 to 1.6 mm]; p = 0.09). Increased lateral compartment acceleration was found when comparing patients with partial ACL tears and those with complete ACL tears (1.5 ± 3.0 m/s2 [95% CI, 0.8 to 2.3 m/s2]; p = 0.0002), but not when comparing patients with complete ACL tears and those who had undergone failed ACL reconstruction (0.1 ± 3.4 m/s2 [95% CI, −2.2 to 2.4 m/s2]; p = 0.93) or patients with partial ACL tears and those who had undergone failed ACL reconstruction (1.7 ± 4.2 m/s2 [95% CI, −0.7 to 4.0 m/s2]; p = 0.16). An increasing lateral compartment translation of the contralateral, ACL-healthy knee was found in patients with partial ACL tears (0.8 mm), those with complete ACL tears (1.2 mm), and those who had undergone failed ACL reconstruction (1.7 mm) (p < 0.05). Conclusions: A progressive increase in rotatory knee laxity, defined by side-to-side differences in quantitative pivot shift, was observed in patients with partial ACL tears, those with complete ACL tears, and those who had undergone failed ACL reconstruction. These results may be helpful when assessing outcomes and considering indications for the management of high-grade rotatory knee laxity. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

To compare subjective and objective outcomes of fibular and combined tibial-fibular (TF)-based posterolateral corner (PLC) reconstruction.A systematic review of literature reporting outcomes of posterolateral corner reconstruction was conducted including outcome studies of surgically treated PLC injuries with a minimum 1-year follow-up, postoperative subjective and objective outcomes including the patient-reported outcome scorings of Lysholm score, International Knee Documentation Committee evaluation (subjective and objective), dial test, and varus stress radiographs.The 32 studies included comprised 40 cohorts: 12 cohorts (n = 350 knees) used a fibular-based technique, and 28 cohorts (n = 593 knees) used a combined TF-based technique. No statistically significant differences were found in patient-reported outcomes or objective clinical measurements comparing the two techniques using the Lysholm score (P = 0.204, τ2 = 3.46), International Knee Documentation Committee evaluation (subjective P = 0.21 τ2 = 15.57; objective P = 0.398), dial test (P = 0.69), or varus stress radiographs (P = 0.98, τ2 = 0.08).This study found no statistically significant differences in subjective or objective clinical outcome measurements after fibular-based versus combined TF-based PLC reconstruction. Further prospective evaluation comparing long-term clinical outcomes, complications, and surgical time may help to elucidate a preferred reconstructive technique.

A 46-year-old man presents with left knee bucking 3 months after open reduction and internal fixation of a left knee inferior pole patella fracture. Radiograph and magnetic resonance imaging evaluation reveal displacement and comminution of the inferior pole of the patella confirming failure of the repair. The purpose of this video is to demonstrate the surgical management of failed inferior pole patella fractures using suture anchors for repair of the patella tendon and augmentation with ipsilateral autologous hamstring grafts.

We present the surgical technique for arthrodesis of the subtalar and calcaneocuboid joints of a Sanders type IV calcaneal fracture nonunion via a distraction bone block arthrodesis technique with tricortical iliac crest allograft combined with reamer/irrigator/aspirator autograft from the patient's femur. A lateral extensile approach to the calcaneus was used for the exposure, which allowed the surgeon to follow the stepwise complex surgical plan outlined here. Calcaneal nonunions are difficult to treat, but good outcomes can be achieved if proper technique with bone grafting is used.

A minimally invasive approach has been widely used for the treatment of calcaneal fractures, however, its downside in exposing the calcaneal body, affects fracture reduction. We used a Steinmann pin retractor mentioned in our previous case series study to solve this issue. To further evaluate the efficacy of this reduction technique, and elucidate its mechanism, we compared it with the control groups in this study. Between March 2017 and November 2020, 52 patients were included in this retrospective comparative study. 20 patients were included in the S-S group (Steinmann pin retractor with internal fixation via the sinus tarsi approach), 17 patients were included in the S group (internal fixation via sinus tarsi approach), and 15 patients were included in the L group (internal fixation via L-shaped approach). Patients in each group were operated on by a distinctly skilled surgeon who is specialized in one of the specified surgeries mentioned above. All patients received positive postoperative radiological and clinical evaluations. The patients were followed up for at least 6 months postoperatively. At the last S-S group follow-up, the VAS value (0.29 ± 0.46) improved compared to the L group. The AOFAS (American Orthopedic Foot and Ankle Society) Ankle-Hindfoot score (94.38 ± 5.05) also improved significantly compared to the S and L groups. The Böhler angle (32.34 ± 3.56°), width (36.48 ± 3.91 mm), and height (88.87 ± 4.12 mm) of the calcaneal improved (34.38 ± 18.50°, -10.13 ± 6.98 mm, 8.75 ± 4.82 mm) compared to the preoperative state, the S and L groups. These parameters (the Böhler angle: 31.76 ± 3.37°, width: 36.47 ± 3.72 mm, height: 87.23 ± 3.83 mm) were maintained at the last follow-up. Steinmann pin retractor effected a sound reduction. It also manifested radiological and clinical advantages over the S and L protocols. By reason of the aforementioned, it could be recommended as useful reduction equipment for the minimally invasive treatment of calcaneal fractures.

» While the gross mechanical abnormalities contributing to posttraumatic osteoarthritis (PTOA) have been well described, new research is demonstrating that these insults to the articular cartilage may also initiate changes in the joint microenvironment that seed the development of PTOA. » A growing amount of literature has identified key biomarkers that exhibit altered expression in the synovial fluid following a knee injury, with a portion of these molecules remaining elevated in the years following an injury. » These biomarkers have the potential to aid in the early detection of PTOA before radiographic evidence becomes apparent. Furthermore, deciphering the processes that occur within the articular microenvironment after trauma may allow for better identification of therapeutic targets for the prevention and earlier treatment of PTOA.

Revision TKA is a serious adverse event with substantial consequences for the patient. As the demand for TKA rises, reducing the risk of revision TKA is becoming increasingly important. Predictive tools based on machine-learning algorithms could reform clinical practice. Few attempts have been made to combine machine-learning algorithms with data from nationwide arthroplasty registries and, to the authors' knowledge, none have tried to predict the likelihood of early revision TKA.We used the Danish Knee Arthroplasty Registry to build models to predict the likelihood of revision TKA within 2 years of primary TKA and asked: (1) Which preoperative factors were the most important features behind these models' predictions of revision? (2) Can a clinically meaningful model be built on the preoperative factors included in the Danish Knee Arthroplasty Registry?The Danish Knee Arthroplasty Registry collects patients' characteristics and surgical information from all arthroplasties conducted in Denmark and thus provides a large nationwide cohort of patients undergoing TKA. As training dataset, we retrieved all preoperative variables of 25,104 primary TKAs from 2012 to 2015. The same variables were retrieved from 6170 TKAs conducted in 2016, which were used as a hold-out year for temporal external validation. If a patient received bilateral TKA, only the first knee to receive surgery was included. All patients were followed for 2 years, with removal, exchange, or addition of an implant defined as TKA revision. We created four different predictive models to find the best performing model, including a regression-based model using logistic regression with least shrinkage and selection operator (LASSO), two classification tree models (random forest and gradient boosting model) and a supervised neural network. For comparison, we created a noninformative model predicting that all observations were unrevised. The four machine learning models were trained using 10-fold cross-validation on the training dataset after adjusting for the low percentage of revisions by over-sampling revised observations and undersampling unrevised observations. In the validation dataset, the models' performance was evaluated and compared by density plot, calibration plot, accuracy, Brier score, receiver operator characteristic (ROC) curve and area under the curve (AUC). The density plot depicts the distribution of probabilities and the calibration plot graphically depicts whether the predicted probability resembled the observed probability. The accuracy indicates how often the models' predictions were correct and the Brier score is the mean distance from the predicted probability to the observed outcome. The ROC curve is a graphical output of the models' sensitivity and specificity from which the AUC is calculated. The AUC can be interpreted as the likelihood that a model correctly classified an observation and thus, a priori, an AUC of 0.7 was chosen as threshold for a clinically meaningful model.Based the model training, age, postfracture osteoarthritis and weight were deemed as important preoperative factors within the machine learning models. During validation, the models' performance was not different from the noninformative models, and with AUCs ranging from 0.57 to 0.60, no models reached the predetermined AUC threshold for a clinical useful discriminative capacity.Although several well-known presurgical risk factors for revision were coupled with four different machine learning methods, we could not develop a clinically useful model capable of predicting early TKA revisions in the Danish Knee Arthroplasty Registry based on preoperative data.The inability to predict early TKA revision highlights that predicting revision based on preoperative information alone is difficult. Future models might benefit from including medical comorbidities and an anonymous surgeon identifier variable or may attempt to build a postoperative predictive model including intra- and postoperative factors as these may have a stronger association with early TKA revisions.

It is imperative that surgeons educate their patients on what to expect following a meniscectomy.A high preinjury activity level, younger age, medial meniscectomy, and smaller meniscal resection play a role in reducing the time until patients are able to return to sport.Improved clinical outcomes ca

Background Isolated femoral and tibial fractures are 2 of the top 5 causes of pediatric orthopaedic hospital admission, yet their simultaneous ipsilateral presentation, the "floating knee" injury, remains rare. Historically, treatment consisted of traction and cast immobilization, which resulted in prolonged periods of immobilization, lengthy hospitalizations, and high rates of malunion. As such, previous authors have recommended fixation of at least 1 bone in the setting of a floating knee injury. This strategy, however, has never been evaluated and the outcomes of modern treatment are unknown. Methods We performed a multicenter retrospective review of the records of pediatric patients with ipsilateral femoral and tibial fractures that had been treated at 11 tertiary care level-I pediatric trauma centers from 2004 to 2014. Outcomes and treatment strategies were assessed with standardized means. Results Over the study period, 130 floating knees in 129 patients met the inclusion criteria for evaluation. The average patient age was 10.2 years, and 63.1% were male. One-third of the patients presented with open injuries, and 83.8% of injuries were related to vehicular trauma. Simple diaphyseal fractures (OTA/AO 32-A and B femoral fractures and OTA/AO 42-A and B tibial fractures) were most common. Intramedullary fixation (rigid or flexible) was the most common treatment strategy for femoral fractures (69.2%). Tibial fractures were treated most commonly with casting (27.7%), followed by flexible intramedullary nailing (24.6%). The mean duration of hospitalization was 9.7 days. Outcomes were excellent in 66.6% of cases and good in 26.4% of cases. Conclusions Previous literature on pediatric floating knee injuries consisted of small case series that were published prior to the introduction of flexible intramedullary nailing to North America. This multicenter study of a large cohort demonstrates a change in practice pattern from a largely nonoperative treatment strategy to operative fixation of at least the femoral fracture. In the present study, this approach led to good or excellent results in 93.1% of cases and was associated with a short duration of hospitalization. Level of evidence Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND Prior research has shown decreased accuracy of meniscal injury detection using magnetic resonance imaging (MRI) for anterior cruciate ligament (ACL)-deficient adult patients as well as ACL-deficient pediatric and adolescent patients. The objectives of this study were the following: (1) assess the diagnostic ability of MRI in detecting meniscal injuries for pediatric and adolescent patients undergoing arthroscopic ACL reconstruction and (2) characterize the unrecognized meniscal injuries. METHODS The sensitivity, specificity, positive predictive value, and negative predictive value of meniscal tears (medial, lateral, or both) on MRI were calculated for the 107 patients in this cohort. Fisher exact tests were used to compare event frequencies between medial meniscal (MM) and lateral meniscal (LM) tears. One-way analysis of variance tests were performed to compare event rates between the location and type of unrecognized meniscal tears. RESULTS The median age of the cohort was 15 (range: 7 to 18). The sensitivity, specificity, positive predictive value, and negative predictive value of MRI in detecting meniscal tears (medial, lateral, or both) in ACL-deficient pediatric and adolescent patients was 62.3%, 68.4%, 78.2%, and 50.0%, respectively. There were 26 (24.3%) cases in which a meniscal injury was not detected on MRI, but was discovered arthroscopically (MM: 5 knees, LM: 20 knees, both: 1 knee). These unrecognized meniscal injuries were more commonly the LM than the MM (77.8%, P-value=0.100), a vertical/longitudinal tear type (77.8%, P-value

Background Missed posterolateral corner (PLC) injuries are a known cause of anterior cruciate ligament reconstruction (ACL) failure in the adult population. Failed ACL reconstruction causes significant morbidity in the skeletally immature pediatric population. There is little literature on the character and potential significance of PLC injuries in skeletally immature patients. Methods Magnetic resonance imaging studies of the knee at a tertiary care children's hospital for patients who underwent an ACL reconstruction without PLC surgery were retrospectively reviewed. Demographic variables were obtained through chart review, and magnetic resonance imaging studies were evaluated for PLC (popliteus, fibular collateral ligament, popliteofibular ligament, and arcuate ligament) injury, and ACL, medial collateral ligament (MCL), bone bruise, fracture, and meniscal pathology by an experienced pediatric musculoskeletal radiologist. Results A total of 50 patients with a mean age at 13.3 years at injury were analyzed. PLC injuries were found in 26 patients (52%), with 7 patients (14%) having a complete tear of a component of the PLC. There was no association between sex (P=0.35), Segond fracture (P=0.09), meniscus injury (P=0.92), or MCL injury (P=0.24) with the risk of PLC injury. There was an association between patient age and PLC injury (P=0.02). For each additional year of age, the odds of PLC injury increased by 1.8 times (odds ratio, 1.8; 95% confidence interval, 1.4-2.2). There was no association between PLC injury and ACL graft failure (P=0.19). Conclusions Missed PLC injuries are a significant source of morbidity and poor clinical outcomes in the management of concomitant ACL injuries in adults. This study demonstrates the prevalence of PLC injuries in the setting of concomitant ACL injuries in the unique skeletally immature patient population. Incomplete PLC injuries are relatively common. Complete PLC injuries are relatively uncommon. PLC injury was more common in older patients. No other concomitant injury predicted the likelihood of PLC injury. Further research is needed regarding the risk of ACL reconstruction failure from associated PLC injury and the indications for PLC reconstruction in skeletally immature patients. Level of evidence Level IV-diagnostic study.

Background Autologous chondrocyte implantation (ACI) and microfracture are two of the main surgical treatment options for articular cartilage lesions of the knee. Consensus regarding the best clinical options to repair knee cartilage lesions is lacking. We undertook a systematic review to clarify the clinical efficacy of ACI and microfracture at minimum mean 5-year follow-up. Methods A literature search was conducted using the MEDLINE, Embase and Cochrane Library databases up to August 2018. Only comparative clinical studies of ACI and microfracture for the treatment of articular cartilage lesions of the knee with level I/Ⅱ evidence were included. Clinical outcomes and the prevalence of treatment failure from each study were extracted and compared. The methodological quality of the included studies was analyzed by means of the PEDro scale. Results Five comparative studies (three randomized controlled trials and two prospective cohort studies) met our eligibility criteria. ACI and microfracture elicited significant improvement in clinical outcomes after 5 years. However, better clinical results with significant differences were found with modified versions of ACI (ACI with a modified collagen membrane [ACI-C] or matrix-applied chondrocyte implantation [MACI]) than with microfracture as determined by the Knee Injury and Osteoarthritis Outcome Score, activities of daily living assessment, Tegner Activity Scale score, and the International Knee Documentation Committee objective and subjective scores. No significant difference was observed in the treatment failure rate between these two methods within a particular study. Conclusions Currently, the best-available evidence suggests that some clinical outcomes of articular cartilage lesions of the knee treated with modified versions of ACI (ACI-C or MACI) can significantly improve patient outcomes at the mid-term follow-up of 5 years compared with those obtained using microfracture.

To facilitate the interpretation of numerical patient-reported outcome measure (PROM) scales, concepts such as the patient acceptable symptom state (PASS) have been introduced. Currently, no PASS thresholds have been established for the Knee injury and Osteoarthritis Outcome Score (KOOS) after total knee arthroplasty. The aims of the current study were to define PASS thresholds for the KOOS subscales and several other generic and knee-specific PROMs at 1 and 3 years after total knee arthroplasty using data from an international, multicenter clinical outcome study of a modern, well-performing implant system.The study cohort consisted of 499 patients undergoing total knee arthroplasty from an international, multicenter study. At 1 and 3 years after a total knee arthroplasty, patients completed the KOOS, EuroQoL 5-dimension 3-level (EQ-5D-3L), EuroQol visual analog scale (EQ-VAS), and numerical rating scales (NRS) for knee-related pain and satisfaction. PASS thresholds were calculated at each follow-up interval using 3 anchor-based approaches, using patient-reported satisfaction as the anchor.According to our satisfaction anchor, 302 (78.9%) of 383 responding patients were satisfied at 1 year, and 242 (80.4%) of 301 responding patients were satisfied at 3 years. PASS thresholds were 84.5 points at 1 year and 87.5 points at 3 years for KOOS pain, 80.5 points at 1 year and 84.0 points at 3 years for KOOS symptoms, 83.0 points at 1 year and 87.5 points at 3 years for KOOS activities of daily living, 66.0 points at 1 year and 66.0 points at 3 years for KOOS quality of life, 83.0 points at 1 year and 90.5 points at 3 years for EQ-VAS, 0.80 point at 1 year and 0.80 point at 3 years for EQ-5D, and 1.8 points at 1 year and 1.8 points at 3 years for NRS pain.The current study is the first, to our knowledge, to propose PASS thresholds for the KOOS subscales at 1 and 3 years after total knee arthroplasty and contributes to PASS literature on other common PROMs. These findings will provide a useful reference for future total knee arthroplasty outcome studies and will help to determine what patients consider to be satisfactory operations.Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

© American Academy of Orthopaedic Surgeons. Background:Extensor mechanism disruption after total knee arthroplasty is a serious complication leading to notable patient morbidity. The purpose of this study is to compare the outcomes of extensor mechanism allograft with synthetic graft reconstruction.Methods:We retrospectively identified all patients who underwent extensor mechanism reconstruction using either allograft or synthetic graft from two high-volume academic arthroplasty institutions between 2006 and 2017. We collected extensor lag, need for ambulatory aids, and patient-reported outcome measures, as well as the incidence of postoperative complications and revision surgeries. We evaluated cost differences, considering both material cost and the need for revision surgery.Results:We identified 27 cases. A significantly greater postoperative extensor lag was found in the allograft group (P = 0.05). Graft failure after synthetic reconstruction was zero, with an overall revision surgery rate of 15%. Graft failure was 21%, and the revision surgery rate was 43% after allograft reconstruction. The allograft cost was significantly higher compared with the synthetic graft cost (P = 0.001). The mean total cost was 4,733.08 CAD for the synthetic group and 24,050.40 CAD for the allograft group (P = 0.17).Discussion:Synthetic reconstruction for extensor mechanism disruption shows benefit in postoperative extensor lag, graft failure, revision surgery, and cost when compared with allograft.Level of Evidence:Level III.

Effects of rehabilitation on knee function, activity and health-related quality of life after soft-tissue knee injury have been widely studied in clinical trials, but there is still a lack of data on the relation between knee muscle strength and athlete's perceived performance to identify sports-risk modifiers. We performed a prospective observational clinical study of knee muscle strength and self-reported health during rehabilitation after unilateral knee soft-tissue injury in recreational sports. Forty-three patients performed isokinetic dynamometry and filled in the Short form Health Survey (SF-36) and the Oxford Knee Score questionnaires before and after 4 months of instructed home strengthening program. We observed significant improvement in peak torque deficit between two limbs during concentric extension (PTDE) and flexion, dynamic control ratio of the involved knee, most of the SF-36 subscales and the Oxford Knee Score values (P ≤ 0.001). Dynamic control ratio of the uninvolved knee values remained below referential values and unchanged. Improvement of PTDE correlated positively with improvement of the bodily pain subscale of SF-36 score (r = 0.51, P < 0.001). Receiver operating characteristic analysis indicated that reduction of pain by at least nine points predicts at least 10% reduction in PTDE, whereby the bodily pain change achieved poor (56%) sensitivity and good (86%) specificity as a rehabilitation success measure for recreational athletes after knee injury. Primary inferior eccentric strength of noninjured knee hamstrings might indicate increased risk of knee injury. Diminished perceived pain predicts strength improvement of the injured knee extensors with poor sensitivity and good specificity.

Eagle, SR, Keenan, KA, Connaboy, C, Wohleber, M, Simonson, A, and Nindl, BC. Bilateral quadriceps strength asymmetry is associated with previous knee injury in military special tactics operators. J Strength Cond Res 33(1): 89-94, 2019-Bilateral strength asymmetries have been related to lower-limb injury in athletes. Given that military populations often participate in recreational sport, in addition to a physically demanding workload, bilateral strength asymmetries may be related to injury in military populations. The purpose of this study was to determine whether isokinetic strength differs between Operators with/without self-reported knee injury (KI), and to examine the odds of displaying a lower-extremity strength asymmetry based on previous KI history. Operators (n = 150) self-reported injury history and performed isokinetic knee strength testing. Cohorts were separated by those who reported/not reported KI. Mean isokinetic knee strength and odds ratios, with subjects' KI history compared with strength differences:10, 10-20, and20%, were calculated. Operators who reported KI demonstrated larger bilateral knee extension (KE) strength differences compared with those who did not report an injury (injured: 13.5 ± 12.9% vs. noninjured: 8.1 ± 5.9%, p = 0.01). Operators with10 or 10-20% KE strength difference had 76-77% reduced odds of previous KI, compared to those with20% strength difference (p0.05). Operators with previous KI demonstrated bilateral differences in KE strength. Those with10 or 10-20% strength differences had reduced odds of reporting previous KI. Strength and conditioning professionals should consider unilateral, targeted exercises in reducing bilateral asymmetry to rectify more balanced strength between limbs. Targeted exercise programs may improve bilateral strength differences and limit reinjury risk.

Knee injuries are common in sports, and postinjury immobilization is often required to protect healing tissues and alleviate pain, but both the injury and the immobilization can lead to a knee contracture. Knee flexion contractures limit performance. Previous research has identified posterior knee capsule fibrosis as a contributor to immobility-induced knee flexion contractures. This study aims to measure posterior knee capsule length at various durations of remobilization after knee immobilization and to correlate with the recovery of knee range of motion.Two hundred fifty-nine male Sprague-Dawley rats had one knee extra-articularly immobilized in flexion with a Delrin® plate at a 45° angle for one of six durations: 1, 2, 4, 8, 16, or 32 wk, followed by spontaneous remobilization after plate removal, which lasted zero, one, two, and four times the duration of immobilization. The contralateral knees served as controls. The posterior knee capsule length was measured by histomorphometry. These measures were correlated with previously published range of motion data from the same cohort of specimens.Knees immobilized for 1 and 2 wk partially recovered posterior capsule length (P0.05). Knees immobilized beyond 2 wk failed to recover posterior capsule length, irrespective of the duration of remobilization (P0.05). The residual posterior capsule shortening correlated with the lack of knee extension (P0.003).For knee injuries requiring more than 2 wk of immobilization, unassisted remobilization will not restore posterior knee capsule shortening and the reduction in knee extension. These results support the role of the posterior capsule in knee joint contracture and the need to minimize the duration of immobility and to assist the recovery of the range of knee extension after a sport injury.

CASE A 41-year-old man presented with a transverse patella fracture and proximal patellar tendon avulsion after a fall from standing. Disruption of the extensor mechanism of the knee at multiple points is rare. He was treated operatively for his patella fracture and patellar tendon avulsion but experienced early failure of the patellar tendon fixation requiring reoperation. Both components of injury ultimately healed, and he returned to function. CONCLUSION This case describes a rare presentation of an uncommon injury pattern affecting the extensor mechanism. This is the first report to describe multifocal failure of the extensor chain from a low-energy mechanism.

Case Patellar fractures after anterior cruciate ligament (ACL) reconstruction with a bone-patellar-tendon-bone (BPTB) autograft are a rare complication with a reported incidence of 0.2% to 2.3%. Treatment has previously been nonoperative splinting, lag screws, or a tension-band construct. We present the case of a 14-year-old adolescent girl who suffered a comminuted patella fracture 4 weeks after an ACL reconstruction using a BPTB autograft who subsequently underwent successful operative fixation through a novel technique with the use of a maxillofacial plate and screw system. Conclusion A maxillofacial plate and screw system is an effective and reliable treatment option for patellar fractures sustained after ACL reconstruction with a BPTB autograft.