Citations

Background: Both the anterior cruciate ligament (ACL) and the medial collateral ligament (MCL) bear load during athletic tasks of landing, cutting, pivoting, and twisting. As dynamic knee valgus is a purported mechanism for ACL injury, the MCL should bear significant strain load with valgus force. Hypothesis: The intact MCL will demonstrate a significant increase in strain upon failure of the ACL at 25° of knee flexion. Study Design: Controlled laboratory study. Methods: In vivo kinetics/kinematics of 44 healthy athletic participants were measured to determine stratification of injury risk (ie, low, medium, and high) in 3 degrees of knee forces/moments (knee abduction moment, anterior tibial shear, and internal tibial rotation). These stratified kinetic values were input into a cadaveric impact simulator to assess ligamentous strain during a simulated landing task. Uniaxial and multiaxial load cells and differential variable reluctance transducer strain sensors were utilized to collect mechanical data for analysis. Conditions of external loads applied to the cadaveric limbs were varied and randomized. Results: ACL strain increased with increased dynamic knee abduction moment (χ 2 [5] = 14.123, P = .0148). The most extreme dynamic knee abduction moment condition demonstrated significantly higher ACL strain compared with lower loaded trials ( P≤ .0203). Similarly, MCL strain increased with dynamic knee abduction moment (χ 2 [5] = 36.578, P < .0001). Matched-pairs analysis compared ACL strain with MCL strain (maximum ACL strain – maximum MCL strain) and demonstrated high strain for the ACL versus the MCL ( S 177 = 6223.5, P < .0001). Conclusion: Although significant, MCL strain had minimal increase with increased dynamic knee abduction moment, and the event of ACL failure did not significantly increase MCL strain when compared with high dynamic knee abduction moment conditions in the cadaveric model. The ACL bears more strain than the MCL at increasing amounts of dynamic knee abduction moment at 25° of knee flexion, which may explain the limited concomitant MCL injury rate that can occur during a dynamic valgus collapse of the knee. Clinical Relevance: These characteristics of ACL and MCL strain are important to understand the mechanisms that drive these injuries at the knee and will improve rehabilitation and injury prevention techniques.

Objective The purpose of this systematic review is to determine (1) current reported treatment options for isolated tibial plateau (TP) cartilage lesions, (2) patient reported outcomes following various treatments, and (3) complication rate and survivorship following various treatments. Design A literature search of PubMed, the Cochrane Library, and CINAHL was conducted adhering to PRISMA guidelines. Patients were included if they had TP cartilage lesions treated with surgery. Lesion characteristics, surgical procedure details, patient reported outcomes, complication, and failure rates were collected. Results Thirteen studies yielded 205 knees with TP cartilage lesions treated surgically. Ages ranged from 12 to 77 years. Surgical techniques included 138 treated with osteochondral allograft transplantation (OCA), 37 treated with osteochondral autograft transfer system (OATS), 11 treated with microfracture, 11 treated with an osteochondral scaffold, and 8 treated with autologous chondrocyte implantation (ACI). The patient-reported outcome measures were heterogeneous, but all reported improvements with the notable exception of one study evaluating microfracture. The rate of complications ranged from 0% to 4.6%. Failure rate ranged from 22% to 46% for OCA and 0% to 16% for OATS. No failures were reported for the additional techniques. Conclusions Various surgical techniques have been utilized for the treatment of TP cartilage lesions. Patient-reported outcome measures were heterogeneous, but improvements were reported following all surgical treatments except for microfracture, which resulted in decreased scores at mid-term follow-up. The complication rate was low for all techniques described. However, the failure rate was higher following unicondylar OCA for salvage treatment of posttraumatic deformities.

Objective The purpose of this systematic review was to determine (1) treatment options for bipolar cartilage lesions of the knee, (2) patient-reported outcomes following various surgical treatments, and (3) complication and failure rates following surgery. Design A literature search of PubMed, the Cochrane Library, and CINHAL was performed using PRISMA guidelines. Patients were included if they had bipolar cartilage lesions of the knee treated surgically. Lesion characteristics, surgical technique, patient-reported outcomes, complication rates, failure rates, and survivorship were recorded. Results Fourteen studies yielded 301 knees treated surgically. Patient age ranged from 15 to 74 years. Surgical techniques included 138 autologous chondrocyte implantation (ACI), 156 osteochondral allograft transplantation (OCA), and 7 osteochondral autograft transfer system (OATS). Seven studies reported a concomitant procedure rate that ranged from 0% to 88%. Eight studies reported that both reciprocal lesions received surgical treatment, while 6 studies did not specify. Lesion size ranged from 1 to 41 cm 2 . All reported postoperative improvements in patient-reported outcomes, but the measures were very heterogeneous. There were no major complications and the rate of minor complications ranged from 0% to 50%. Survivorship ranged from 40% to 100% for OCA, 76% to 95% for ACI, and 100% for the 1 study evaluating OATS. Conclusions Bipolar cartilage lesions of the knee typically involve a large surface area and are most commonly treated with ACI or OCA, while OATS may be an option for smaller lesions. Improvements in mid-term patient-reported outcomes were reported for all surgical procedures and they can be performed safely with a low rate of major complications.

Purpose To (1) define the rate of delayed surgery, between 1 and 10 years after injury, in a population‐based study of patients with posterior shoulder instability (PSI), (2) evaluate predictive factors associated with delayed repair, and (3) identify differences between the nonoperative and operative groups at long‐term follow‐up. Methods A population‐based retrospectively reviewed study of all patients with PSI from January 1, 1994, to December 31, 2015, was performed. Inclusion required a clinical diagnosis of PSI combined with supporting imaging. Complete medical records were reviewed for 2,091 potential cases. Kaplan‐Meier estimates were used to calculate survival. Landmark survival analysis was performed to identify predictors of conversion to surgery. Results The study included 143 patients with PSI, 79 of whom were managed nonoperatively for at least 1 year after diagnosis. After the first year, survival free of surgery was 78.3% at 1 year, 63.1% at 5 years, and 51.5% at 10 years. There was a trend toward increased surgery in patients with a body mass index > 35 ( P = .10; hazard ratio = 2.32; confidence interval, 0.8‐6.8). Nonthrowing athletes (including contact/weight‐lifting athletes) showed a trend toward an increased risk for surgery ( P = . 07). Patients who underwent surgery were significantly more likely to have progression in arthritis ( P = . 02; hazard ratio = 4.0; confidence interval, 1.2‐13.2). Conclusions Nonoperative management was performed for at least 1 year in over half of patients diagnosed with PSI. Overall, long‐term follow‐up demonstrates that 46% of these patients converted to surgery between 1 and 10 years after initial diagnosis. Ultimately, 70% of patients diagnosed with PSI go on to surgical intervention. Patients who underwent surgery at any time point were at an increased risk of radiographic progression of arthritis at a minimum of 5 years of follow‐up. Level of Evidence Level III, cohort study.

Background: Anterior cruciate ligament (ACL) tears and concomitant medial collateral ligament (MCL) injuries are known to occur during dynamic athletic tasks that place combinatorial frontal and transverse plane loads on the knee. A mechanical impact simulator that produces clinical presentation of ACL injury allows for the quantification of individual loading contributors leading to ACL failure. Purpose/Hypothesis: The objective was to delineate the relationship between knee abduction moment, anterior tibial shear, and internal tibial rotation applied at the knee and ACL strain during physiologically defined simulations of impact at a knee flexion angle representative of initial contact landing from a jump. The hypothesis tested was that before ACL failure, abduction moment would induce greater change in ACL strain during landing than either anterior shear or internal rotation. Study Design: Controlled laboratory study. Methods: Nineteen cadaveric specimens were subjected to simulated landings in the mechanical impact simulator. During simulations, external knee abduction moment, internal tibial rotation moment, and anterior tibial shear loads were derived from a previously analyzed in vivo cohort and applied to the knee in varying magnitudes with respect to injury risk classification. Implanted strain gauges were used to track knee ligament displacement throughout simulation. Kruskal-Wallis tests were used to assess strain differences among loading factors, with Wilcoxon each pair post hoc tests used to assess differences of magnitude within each loading. Results: Each loading factor significantly increased ACL strain ( P < .005). Within factors, the high-risk magnitude of each factor significantly increased ACL strain relative to the baseline condition ( P≤ .002). However, relative to knee abduction moment specifically, ACL strain increased with each increased risk magnitude ( P≤ .015). Conclusion: Increased risk levels of each load factor contributed to increased levels of ACL strain during a simulated jump landing. The behavior of increased strain between levels of increased risk loading was most prevalent for changes in knee abduction moment. This behavior was observed in the ACL and MCL. Clinical Relevance: Knee abduction moment may be the predominant precursor to ACL injury and concomitant MCL injury. As knee abduction occurs within the frontal plane, primary preventative focus should incorporate reduction of frontal plane knee loading in landing and cutting tasks, but secondary reduction of transverse plane loading could further increase intervention efficacy. Constraint of motion in these planes should restrict peak ACL strain magnitudes during athletic performance.

Background: Anterior cruciate ligament (ACL) injury is one of the most frequent orthopaedic injuries and reasons for time loss in sports and carries significant implications, including posttraumatic osteoarthritis (OA). Instability associated with ACL injury has been linked to the development of secondary meniscal tears (defined as tears that develop after the initial ACL injury). To date, no study has examined secondary meniscal tears after ACL injury and their effect on OA and arthroplasty risk. Purpose: To describe the rates and natural history of secondary meniscal tears after ACL injury and to determine the effect of meniscal tear treatment on the development of OA and conversion to total knee arthroplasty (TKA). Study Design: Cohort study; Level of evidence, 3. Methods: A geographic database of >500,000 patients was reviewed to identify patients with primary ACL injuries between January 1, 1990, and December 31, 2005. Information was collected with regard to ACL injury treatment, rates/characteristics of the secondary meniscal tears, and outcomes, including development of OA and conversion to TKA. Kaplan-Meier and adjusted multivariate survival analyses were performed to test for the effect of meniscal treatment on survivorship free of OA and TKA. Results: Of 1398 primary ACL injuries, the overall rate of secondary meniscal tears was 16%. Significantly lower rates of secondary meniscal tears were noted among patients undergoing acute ACL reconstruction within 6 months (7%) as compared with patients with delayed ACL reconstruction (33%, P < .01) and nonoperative ACL management (19%, P < .01). Of the 235 secondary meniscal tears identified (196 patients), 11.5% underwent repair, 73% partial meniscectomy, and 16% were treated nonoperatively. Tears were most often medial in location (77%) and complex in morphology (56% of medial tears, 54% of lateral tears). At the time of final follow-up, no patient undergoing repair of a secondary meniscal tear (0%) underwent TKA, as opposed to 10.9% undergoing meniscectomy and 6.1% receiving nonoperative treatment ( P = .28). Conclusion: Secondary meniscal tears after ACL injury are most common among patients undergoing delayed surgical or nonoperative treatment of their primary ACL injuries. Secondary tears often present as complex tears of the medial meniscus and result in high rates of partial meniscectomy.

Objectives The purpose of this study was to describe an arthroscopic surgical approach to identify and expose the popliteus tendon (PT), posterior fibular head, Fibular collateral ligament (FCL), popliteal fibular ligament (PFL), biceps femoris tendon, and the peroneal nerve. Methods 10 fresh human cadaveric knees were examined arthroscopically using standard anterior and posterior portals. The use of a transeptal approach with both posteromedial and posterolateral portals was required using a standard 30 degrees arthroscope. Optimal portal placement and specific technique and sequence for appropriate visualization of the PLC structures were tested and documented. Results In all specimens, all the PLC structures that we attempted to identify were successfully visualized. These included the PT, posterior fibular head, the FCL, the PFL, biceps femoris tendon, peroneal nerve, PT and FCL femoral attachments. Conclusion This study demonstrated that the identification and exposure of the PLC structures using an all arthroscopic approach can be successfully performed with precise portal placement. This technique may serve as a basis for arthroscopic treatment of PLC injuries.

Abstract Focal cartilage defects lead to significant pain and disability, prompting the development of various options for biologic restoration of the articular surface. Although each technique and biologic implant provides various advantages and associated limitations, matrix‐induced autologous chondrocyte implantation (MACI) has gained popularity given promising long‐term results. We present a technique for the facile implantation of MACI membranes using cookie cutter instrumentation to aid in defect debridement and graft preparation. The technique described allows for efficient operative workflow while ensuring the creation of vertical, stable defect edges and a form‐fitting MACI membrane in a readily implemented fashion. Technique Video video See video under supplementary data.

Background: The lack of a standardized system for describing cell therapies acts as a barrier to advancement in clinical and basic research and practice. The aim of this study was to establish an international expert consensus on strategies to improve standardization and transparency when describing cell therapies. The secondary aim was to develop a consensus among experts on the contents of a standardized tool for describing cell therapies. Methods: The need for expert consensus on strategies to improve cell therapy communication was confirmed at the American Academy of Orthopaedic Surgeons/National Institutes of Health Optimizing Clinical Use of Biologics Symposium in 2018. A working group of 6 experts convened an international consensus process involving clinicians and basic scientists using validated Delphi methodology. This iterative process was used to define statements on communication of cell therapies and develop a standardized tool for describing cell therapies. Results: Thirty-four experts completed 3 rounds survey with use of the Delphi process. After 3 rounds, 27 statements relating to existing nomenclature, solutions to improve communication, ideal characteristics of a framework, mandatory elements of a new framework, and future work to facilitate application reached consensus with >80% agreement and <5% disagreement. Consensus was reached on the contents of a tool for improving standardization and transparency when describing cell therapies. This tool, dubbed “DOSES,” is based on the reporting of 5 core items: donor (i.e., autologous, allogeneic, xenogeneic), origin of tissue, separation from other cell types/preparation method, exhibited cell characteristics associated with behavior, and the site of delivery. Conclusions: This study has established expert consensus on the communication of cell therapies. The DOSES tool has been developed to improve standardization and transparency in describing cell therapies. Clinical Relevance: The DOSES tool for describing cell therapies can be utilized by researchers, clinicians, regulators, and industry professionals to improve standardization and transparency when describing cell therapies. The use of this tool may allow clinicians and patients to better understand the characteristics of current and future cell preparations.

Background: Hip arthroscopy is becoming more advanced and commonly performed. However, significant controversy exists regarding whether high-grade acetabular cartilage lesions should be treated with debridement/abrasion or microfracture. In addition, patients treated with microfracture are subject to extended protected weightbearing rehabilitation to mitigate risk of subchondral plate fracture and to protect fibrocartilage tissue formation. Purpose: To determine the midterm patient-reported outcomes and failure rate of patients with grade 3 and 4 acetabular labrum articular disruption (ALAD) lesions managed with debridement/abrasion or microfracture. Study Design: Cohort study; Level of evidence, 3. Methods: Primary arthroscopic labral repair cases at 2 centers from November 2008 to April 2016 were reviewed for patients aged <55 years with unipolar ALAD grade 3 and 4 chondrolabral acetabular delamination. Patients undergoing microfracture and debridement/abrasion were compared using the visual analog pain scale (VAS), modified Harris Hip Score (mHHS), and Hip Outcome Score–Sports-Specific Subscale (HOS-SSS) to determine predictors of outcomes and failure. Results: A total of 113 hips in 110 patients (66 males, 44 females; mean age, 34.5 ± 1.1 years) undergoing debridement/abrasion (n = 82) or microfracture (n = 31) were followed for a mean of 4.9 years (range, 2.0-8.5 years). Lesion size was not statistically different between the debridement/abrasion (1.3 ± 1.0 cm 2 ) and microfracture cohorts (1.4 ± 1.0 cm 2 ) ( P = .47). Patients undergoing debridement/abrasion achieved 3.6-point mean improvements in VAS ( P < .01), 21.2-point improvements in mHHS ( P < .01), and 25.4-point improvements in HOS-SSS ( P < .01), which were not significantly different from those observed in microfracture patients ( P≥ .20). The 5-year rate of survival free of revision surgery was 84.0% in the debridement/abrasion group and 85.6% in the microfracture group ( P = .78). The cartilage treatment technique was found not to be predictive of revision risk during both univariate (hazard ratio [HR], 1.01; P = .98) and multivariate (HR, 0.93; P = .90) analysis accounting for patient age, lesion grade, and acetabular coverage. Conclusion: Patients undergoing debridement/abrasion of high-grade unipolar acetabular cartilage lesions demonstrate similar outcome scores and revision rates compared with those of patients undergoing microfracture. These outcomes support the consideration of preferential debridement/abrasion at the discretion of the treating surgeon to optimize recovery while maintaining established positive outcomes after hip arthroscopy.