Are Weightbearing Restrictions Required After Microfracture for Isolated Chondral Lesions of the Knee? A Review of the Basic Science and Clinical Literature.

CONTEXT: A strict rehabilitation protocol is traditionally followed after microfracture, including weightbearing restrictions for 2 to 6 weeks. However, such restrictions pose significant disability, especially in a patient population that is younger and more active. EVIDENCE ACQUISITION: An extensive literature review was performed through PubMed and Google Scholar of all studies through December 2018 related to microfracture, including biomechanical, basic science, and clinical studies. For inclusion, clinical studies had to report weightbearing status and outcomes with a minimum 12-month follow-up. STUDY DESIGN: Clinical review. LEVEL OF EVIDENCE: Level 3. RESULTS: Review of biomechanical and biology studies suggest new forming repair tissue is protected from shear forces of knee joint loading by the cartilaginous margins of the defect. This margin acts as a shoulder to maintain axial height and allow for tissue remodeling up to at least 12 months after surgery, well beyond current weight bearing restriction trends. A retrospective case-control study showed that weightbearing status postoperatively had no effect on clinical outcomes in patients who underwent microfracture for small chondral (<2 mm2) defects. In fact, 1 survey showed that many orthopaedic surgeons currently do not restrict weightbearing after microfracture. CONCLUSION: This clinical literature review suggests that weightbearing restrictions may not be required after microfracture for isolated tibiofemoral chondral lesions of the knee. STRENGTH OF RECOMMENDATION TAXONOMY: C.

Reconsidering Reciprocal Length Patterns of the Anteromedial and Posterolateral Bundles of the Anterior Cruciate Ligament During In Vivo Gait.

BACKGROUND: Some cadaveric studies have indicated that the anterior cruciate ligament (ACL) consists of anteromedial and posterolateral bundles that display reciprocal function with regard to knee flexion. However, several in vivo imaging studies have suggested that these bundles elongate in parallel with regard to flexion. Furthermore, the most appropriate description of the functional anatomy of the ACL is still debated, with the ACL being described as consisting of 2 or 3 bundles or as a continuum of fibers. HYPOTHESIS: As long as their origination and termination locations are defined within the ACL attachment site footprints, ACL bundles elongate in parallel with knee extension during gait. STUDY DESIGN: Descriptive laboratory study. METHODS: High-speed biplanar radiographs of the right knee joint were obtained during gait in 6 healthy male participants (mean ± SD: body mass index, 25.5 ± 1.2 kg/m2; age, 29.2 ± 3.8 years) with no history of lower extremity injury or surgery. Three-dimensional models of the right femur, tibia, and ACL attachment sites were created from magnetic resonance images. The bone models were registered to the biplanar radiographs, thereby reproducing the in vivo positions of the knee joint. For each knee position, the distances between the centroids of the ACL attachment sites were used to represent ACL length. The lengths of 1000 virtual bundles were measured for each participant by randomly sampling locations on the attachment site surfaces and measuring the distances between each pair of locations. Spearman rho rank correlations were performed between the virtual bundle lengths and ACL length. RESULTS: The virtual bundle lengths were highly correlated with the length of the ACL, defined as the distance between the centroids of the attachment sites (rho = 0.91 ± 0.1, across participants; P < 5 × 10-5). The lengths of the bundles that originated and terminated in the anterior and medial aspects of the ACL were positively correlated (rho = 0.81 ± 0.1; P < 5 × 10-5) with the lengths of the bundles that originated and terminated in the posterior and lateral aspects of the ACL. CONCLUSION: As long as their origination and termination points are specified within the footprint of the attachment sites, ACL bundles elongate in parallel as the knee is extended. CLINICAL RELEVANCE: These data elucidate ACL functional anatomy and may help guide ACL reconstruction techniques.

In vivo attachment site to attachment site length and strain of the ACL and its bundles during the full gait cycle measured by MRI and high-speed biplanar radiography.

The purpose of this study was to measure in vivo attachment site to attachment site lengths and strains of the anterior cruciate ligament (ACL) and its bundles throughout a full cycle of treadmill gait. To obtain these measurements, models of the femur, tibia, and associated ACL attachment sites were created from magnetic resonance (MR) images in 10 healthy subjects. ACL attachment sites were subdivided into anteromedial (AM) and posterolateral (PL) bundles. High-speed biplanar radiographs were obtained as subjects ambulated at 1 m/s. The bone models were registered to the radiographs, thereby reproducing the in vivo positions of the bones and ACL attachment sites throughout gait. The lengths of the ACL and both bundles were estimated as straight line distances between attachment sites for each knee position. Increased attachment to attachment ACL length and strain were observed during midstance (length = 28.5 ±â€¯2.6 mm, strain = 5 ±â€¯4%, mean ±â€¯standard deviation), and heel strike (length = 30.5 ±â€¯3.0 mm, strain = 12 ±â€¯5%) when the knee was positioned at low flexion angles. Significant inverse correlations were observed between mean attachment to attachment ACL lengths and flexion (rho = -0.87, p < 0.001), as well as both bundle lengths and flexion (rho = -0.86, p < 0.001 and rho = -0.82, p < 0.001, respectively). AM and PL bundle attachment to attachment lengths were highly correlated throughout treadmill gait (rho = 0.90, p < 0.001). These data can provide valuable information to inform design criteria for ACL grafts used in reconstructive surgery, and may be useful in the design of rehabilitation and injury prevention protocols.

Editorial Commentary: When Is Too Small, Too Small? Allograft Augmentation of Autologous Hamstring Grafts During Anterior Cruciate Ligament Reconstruction.

Soft tissue allograft augmentation of small hamstring autografts, so-called hybrid grafts, has been proposed as an option during anterior cruciate ligament reconstruction (ACL-R). However, notable concerns exist with both small autograft use and allograft use during ACL-R, particularly in young, active patients. We currently choose to augment hamstring autografts with diameters <8.0 mm, adding only enough allograft to create a hybrid graft with an overall diameter no larger than 8.5 mm. Based on the available evidence, surgeons continue to seek the tipping point where the benefit of additional allograft tissue exceeds the consequence of its use.

Return to Sport After Pediatric Anterior Cruciate Ligament Reconstruction and Its Effect on Subsequent Anterior Cruciate Ligament Injury.

BACKGROUND: Anterior cruciate ligament (ACL) graft failure and contralateral ACL tears are more frequent in children and adolescents than adults. The reasons for higher subsequent injury rates in this population are incompletely understood. METHODS: We analyzed a continuous cohort of patients who were <18 years of age. Subjects underwent isolated, primary ACL reconstruction with autograft between 2006 and January 1, 2014, and had a minimum 2-year follow-up. Return-to-sport characteristics were described, and multivariable Cox regression modeling was used to identify predictors of a second ACL injury. Candidate variables included patient factors (age, sex, physeal status, tibial slope, notch width index), surgical characteristics (graft type, surgical technique), measures of recovery (time to return to sport, duration of physical therapy), and patients' preoperative and postoperative sports involvement (primary and secondary sports, number of sports). RESULTS: A total of 112 subjects met inclusion criteria; of these patients, 85 (76%) had complete follow-up data and were analyzed. The mean age (and standard deviation) was 13.9 ± 2.1 years (range, 6 to 17 years); 77% had open physes. The mean follow-up was 48.3 ± 15.3 months. Seventy-seven patients (91%) returned to sports, and 84% returned to the same sport. The mean Marx activity score at the time of the latest follow-up was 13.7 ± 3.5 points. Patients were involved in fewer sports after ACL reconstruction, 1.48 ± 0.92 compared with 1.83 ± 1.01 sports before reconstruction (p = 0.002). Sixteen patients (19%) sustained an ACL graft rupture, 11 patients (13%) sustained a contralateral ACL tear, and 1 of these patients (1%) sustained both. The overall prevalence of a second ACL injury was 32%. Time to return to sport was the only significant predictor of a second ACL injury, with a slower return being protective (hazard ratio per month, 0.87 [95% confidence interval, 0.73 to 0.99]; p = 0.04). CONCLUSIONS: Pediatric athletes return to sports at a high rate (91%) after ACL reconstruction. Unfortunately, the prevalence of a second ACL injury is high at 32%. Within this population, an earlier return to sport is predictive of a second ACL injury. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Matrix metalloproteinase activity and prostaglandin E2 are elevated in the synovial fluid of meniscus tear patients.

PURPOSE: Meniscus tears are a common knee injury and are associated with the development of post-traumatic osteoarthritis (OA). The purpose of this study is to evaluate potential OA mediators in the synovial fluid and serum of meniscus tear subjects compared to those in the synovial fluid of radiographic non-OA control knees. MATERIALS AND METHODS: Sixteen subjects with an isolated unilateral meniscus injury and six subjects who served as reference controls (knee Kellgren-Lawrence grade 0-1) were recruited. Twenty-one biomarkers were measured in serum from meniscus tear subjects and in synovial fluid from both groups. Meniscus tear subjects were further stratified by tear type to assess differences in biomarker levels. RESULTS: Synovial fluid total matrix metalloproteinase (MMP) activity and prostaglandin E2 (PGE2) were increased 25-fold and 290-fold, respectively, in meniscus tear subjects as compared to reference controls (p < 0.05). Synovial fluid MMP activity and PGE2 concentrations were positively correlated in meniscus tear subjects (R = 0.83, p < 0.0001). In meniscus tear subjects, synovial fluid levels of MMP activity, MMP-2, MMP-3, sGAG, COMP, IL-6, and PGE2 were higher than serum levels (p < 0.05). Subjects with complex meniscus tears had higher synovial fluid MMP-10 (p < 0.05) and reduced serum TNFα and IL-8 (p < 0.05) compared to other tear types. CONCLUSIONS: Given the degradative and pro-inflammatory roles of MMP activity and PGE2, these molecules may alter the biochemical environment of the joint. Our findings suggest that modulation of PGE2 signaling, MMP activity, or both following a meniscus injury may be targets to promote meniscus repair and prevent OA development.

Effect of normal gait on in vivo tibiofemoral cartilage strains.

Altered cartilage loading is believed to be associated with osteoarthritis development. However, there are limited data regarding the influence of normal gait, an essential daily loading activity, on cartilage strains. In this study, 8 healthy subjects with no history of knee surgery or injury underwent magnetic resonance imaging of a single knee prior to and following a 20-min walking activity at approximately 1.1m/s. Bone and cartilage surfaces were segmented from these images and compiled into 3-dimensional models of the tibia, femur, and associated cartilage. Thickness changes were measured across a grid of evenly spaced points spanning the models of the articular surfaces. Averaged compartmental strains and local strains were then calculated. Overall compartmental strains after the walking activity were found to be significantly different from zero in all four tibiofemoral compartments, with tibial cartilage strain being significantly larger than femoral cartilage strain. These results provide baseline data regarding the normal tibiofemoral cartilage strain response to gait. Additionally, the technique employed in this study has potential to be used as a "stress test" to understand how factors including age, weight, and injury influence tibiofemoral cartilage strain response, essential information in the development of potential treatment strategies for the prevention of osteoarthritis.

Lower Extremity Movement Differences Persist After Anterior Cruciate Ligament Reconstruction and When Returning to Sports.

OBJECTIVE: To examine how landing mechanics change in patients after anterior cruciate ligament reconstruction (ACL-R) between 6 months and 12 months after surgery. DESIGN: Case-series. SETTING: Laboratory. PARTICIPANTS: Fifteen adolescent patients after ACL-R participated. INTERVENTIONS: Lower extremity three-dimensional motion analysis was conducted during a bilateral stop jump task in patients at 6 and 12 months after ACL-R. Joint kinematic and kinetic data, in addition to ground reaction forces, were collected at each time point. MAIN OUTCOME MEASURES: During the stop jump landing, the peak joint moments and the initial and peak joint motion at the ankle, knee, and hip were examined. The peak vertical ground reaction force was also examined. RESULTS: Interactions were observed for both the peak knee (P = 0.03) and hip extension moment (P = 0.07). However, only the hip extension moment was symmetrical level at 12 months. Statistically significant (P < 0.05) side-to-side differences existed for the ankle angle at initial contact, peak plantarflexion moment, peak hip flexion angle, and peak impact vertical ground reaction force independent of time. CONCLUSIONS: The findings of this study suggest that sagittal plane moments at the knee and hip demonstrate an increase in symmetry between 6 months and 1 year after ACL-R surgery, however, symmetry of the knee extension moment is not established by 12 months after surgery. The lack of change in the variables across time was unexpected. As a result, it is inappropriate to expect a change in landing mechanics solely as a result of time alone after discharge from rehabilitation.

Inside-Out or Outside-In Suturing Should Not Be Considered the Standard Repair Method for Radial Tears of the Midbody of the Lateral Meniscus: A Systematic Review and Meta-Analysis of Biomechanical Studies.

The purpose was to evaluate which meniscal repair technique for radial tears of the midbody of the lateral meniscus demonstrates the best biomechanical properties. An electronic literature search was conducted using PubMed, EMBASE, CINAHL, and ScienceDirect databases. Biomechanical studies investigating the repair characteristics of radial tears in the midbody of the lateral meniscus were included. After appropriate screening, a total of 54 studies were reviewed in detail (full text), and 6 met inclusion criteria. The most common cause of exclusion was the investigation of longitudinal tears. Only two studies could be meta-analyzed. Stiffness was significantly higher for all-inside compared with inside-out repair techniques (p = 0.0009). No significant differences were observed between both suture methods for load to failure (p = 0.45). However, both studies used different all-inside devices and suture constructs. No clear conclusions can be drawn from the comparison of both types of repairs for displacement, site of failure, or contact pressure changes. Overall, there are no conclusive data to suggest that inside-out or outside-in suture repair has better load to failure or stiffness, less displacement, or different site of failure compared with all-inside repair. According to biomechanical data, it is under surgeon's preference to elect one repair technique over the other.

Gender Differences in Plantar Loading During an Unanticipated Side Cut on FieldTurf.

OBJECTIVE: To determine whether force-time integral (FTI) and maximum force (MF) are significantly different between genders when performing an unanticipated side cut on FieldTurf. DESIGN: Thirty-two collegiate athletes (16 men and 16 women) completed 12 unanticipated cutting trials, while plantar pressure data were recorded using Pedar-X insoles. SETTING: Controlled Laboratory Study. PARTICIPANTS: Division I cleated sport athletes with no previous foot and ankle surgery, no history of lower extremity injury in the past 6 months, and no history of metatarsal stress fracture. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Maximum force and the FTI in the total foot, medial midfoot (MMF), lateral midfoot (LMF), medial forefoot (MFF), middle forefoot (MiddFF), and the lateral forefoot (LFF). RESULTS: Males had a greater FTI beneath the entire foot (TF) (P < 0.001). Females had a significantly higher MF beneath the LMF (P = 0.001), MiddFF (P < 0.001), and LFF (P = 0.001). Males had a significantly greater MF beneath the MMF (P = 0.003) and greater FTI beneath the MMF (P < 0.001) and MFF (P = 0.002). CONCLUSIONS: Significant differences in plantar loading exist between genders with males demonstrating increased loading beneath the TF in comparison with females. Females had overall greater loading on the lateral column, whereas males had greater loading on the medial column of the foot. CLINICAL RELEVANCE: The results of this study indicate that plantar loading is different between genders; therefore, altering cleated footwear to be gender specific may result in more optimal foot loading patterns. Optimizing cleated shoe design could decrease the risk for metatarsal stress fractures.

Does adjustable-loop femoral cortical suspension loosen after anterior cruciate ligament reconstruction? A retrospective comparative study.

BACKGROUND: Recent biomechanical research has suggested that adjustable-loop graft suspension constructs in anterior cruciate ligament (ACL) reconstruction may loosen after deployment. Our objective was to compare short-term knee stability and graft failure rate between adjustable-loop and fixed-loop femoral cortical suspension in patients undergoing primary ACL reconstruction. METHODS: A consecutive series of 188 patients who underwent primary ACL reconstruction using hamstrings autograft by a single surgeon were divided into two groups; 73 received adjustable-loop (TightRope RT (Arthrex Inc., Naples, FL)) and 115 received fixed-loop (RetroButton (Arthrex Inc., Naples, FL)) femoral cortical suspension. The two groups were compared at six months, one year, and two years postoperatively using KT-1000 arthrometer testing and graft failure rate (revision surgery, grade 2+ Lachman test, any pivot shift, >5mm side-to-side KT-1000 difference). RESULTS: There was no significant difference between the two groups in maximum side-to-side difference in KT-1000 testing at six months (mean 1.51mm (adjustable-loop group) vs. 1.79mm (fixed-loop group), p=0.23), one year (mean 1.44mm vs. 1.64mm, p=0.48), or two years (mean 1.14mm vs. 1.07mm, p=0.90) postoperatively. There was no significant difference between the two groups in rate of graft failure (10% vs. 11%, p=0.71) or timing of graft failure in affected patients (mean 11.4months vs. 13.8months, p=0.51). CONCLUSIONS: We found no significant difference in postoperative knee stability or graft failure rate between adjustable-loop and fixed-loop femoral cortical suspension in patients undergoing primary ACL reconstruction. Our results suggest that adjustable-loop suspension does not clinically loosen after ACL reconstruction. LEVEL OF EVIDENCE: III (retrospective cohort study).

Cost-effectiveness analysis of the diagnosis of meniscus tears.

BACKGROUND: Diagnostic imaging represents the fastest growing segment of costs in the US health system. This study investigated the cost-effectiveness of alternative diagnostic approaches to meniscus tears of the knee, a highly prevalent disease that traditionally relies on MRI as part of the diagnostic strategy. PURPOSE: To identify the most efficient strategy for the diagnosis of meniscus tears. STUDY DESIGN: Economic and decision analysis; Level of evidence, 1. METHODS: A simple-decision model run as a cost-utility analysis was constructed to assess the value added by MRI in various combinations with patient history and physical examination (H&P). The model examined traumatic and degenerative tears in 2 distinct settings: primary care and orthopaedic sports medicine clinic. Strategies were compared using the incremental cost-effectiveness ratio (ICER). RESULTS: In both practice settings, H&P alone was widely preferred for degenerative meniscus tears. Performing MRI to confirm a positive H&P was preferred for traumatic tears in both practice settings, with a willingness to pay of less than US$50,000 per quality-adjusted life-year. Performing an MRI for all patients was not preferred in any reasonable clinical scenario. The prevalence of a meniscus tear in a clinician's patient population was influential. For traumatic tears, MRI to confirm a positive H&P was preferred when prevalence was less than 46.7%, with H&P preferred above that. For degenerative tears, H&P was preferred until the prevalence reaches 74.2%, and then MRI to confirm a negative was the preferred strategy. In both settings, MRI to confirm positive physical examination led to more than a 10-fold lower rate of unnecessary surgeries than did any other strategy, while MRI to confirm negative physical examination led to a 2.08 and 2.26 higher rate than H&P alone in primary care and orthopaedic clinics, respectively. CONCLUSION: For all practitioners, H&P is the preferred strategy for the suspected degenerative meniscus tear. An MRI to confirm a positive H&P is preferred for traumatic tears for all practitioners. Consideration should be given to implementing alternative diagnostic strategies as well as enhancing provider education in physical examination skills to improve the reliability of H&P as a diagnostic test. CLINICAL RELEVANCE: Alternative diagnostic strategies that do not include the use of MRI may result in decreased health care costs without harm to the patient and could possibly reduce unnecessary procedures.

Improving residency training in arthroscopic knee surgery with use of a virtual-reality simulator. A randomized blinded study.

BACKGROUND: There is a paucity of articles in the surgical literature demonstrating transfer validity (transfer of training). The purpose of this study was to assess whether skills learned on the ArthroSim virtual-reality arthroscopic knee simulator transferred to greater skill levels in the operating room. METHODS: Postgraduate year-3 orthopaedic residents were randomized into simulator-trained and control groups at seven academic institutions. The experimental group trained on the simulator, performing a knee diagnostic arthroscopy procedure to a predetermined proficiency level based on the average proficiency of five community-based orthopaedic surgeons performing the same procedure on the simulator. The residents in the control group continued their institution-specific orthopaedic education and training. Both groups then performed a diagnostic knee arthroscopy procedure on a live patient. Video recordings of the arthroscopic surgery were analyzed by five pairs of expert arthroscopic surgeons blinded to the identity of the residents. A proprietary global rating scale and a procedural checklist, which included visualization and probing scales, were used for rating. RESULTS: Forty-eight (89%) of the fifty-four postgraduate year-3 residents from seven academic institutions completed the study. The simulator-trained group averaged eleven hours of training on the simulator to reach proficiency. The simulator-trained group performed significantly better when rated according to our procedural checklist (p = 0.031), including probing skills (p = 0.016) but not visualization skills (p = 0.34), compared with the control group. The procedural checklist weighted probing skills double the weight of visualization skills. The global rating scale failed to reach significance (p = 0.061) because of one extreme outlier. The duration of the procedure was not significant. This lack of a significant difference seemed to be related to the fact that residents in the control group were less thorough, which shortened their time to completion of the arthroscopic procedure. CONCLUSIONS: We have demonstrated transfer validity (transfer of training) that residents trained to proficiency on a high-fidelity realistic virtual-reality arthroscopic knee simulator showed a greater skill level in the operating room compared with the control group. CLINICAL RELEVANCE: We believe that the results of our study will stimulate residency program directors to incorporate surgical simulation into the core curriculum of their residency programs.

Meniscal root entrapment of an osteochondritis dissecans loose body.

Loose bodies are relatively common in the knee. On radiographs they can often be seen in the medial and lateral gutters, intercondylar notch, and the posterior compartment. At times an apparent loose body is not free to move in the knee because it has been covered by synovium and is no longer mobile. It is uncommon for an osteochondral loose body to become incorporated into meniscal tissue. We report a case of an apparent loose body becoming incorporated into the posterior horn and root of the medial meniscus. We are not aware that this condition has been previously reported. Because removing the entire loose body would have destabilized the posterior root of the medial meniscus, it is important to be aware of this potential occurrence.

Changes in landing mechanics in patients following anterior cruciate ligament reconstruction when wearing an extension constraint knee brace.

BACKGROUND: Anterior cruciate ligament (ACL) reconstruction is associated with a high incidence of second tears (graft tears and contralateral ACL tears). These secondary tears have been attributed to asymmetrical lower extremity mechanics. Knee bracing is one potential intervention that can be used during rehabilitation that has the potential to normalize lower extremity asymmetry; however, little is known about the effect of bracing on movement asymmetry in patients following ACL reconstruction. HYPOTHESIS: Wearing a knee brace would increase knee joint flexion and joint symmetry. It was also expected that the joint mechanics would become more symmetrical in the braced condition. OBJECTIVE: To examine how knee bracing affects knee joint function and symmetry over the course of rehabilitation in patients 6 months following ACL reconstruction. STUDY DESIGN: Controlled laboratory study. LEVEL OF EVIDENCE: Level 3. METHODS: Twenty-three adolescent patients rehabilitating from ACL reconstruction surgery were recruited for the study. The subjects all underwent a motion analysis assessment during a stop-jump activity with and without a functional knee brace on the surgical side that resisted extension for 6 months following the ACL reconstruction surgery. Statistical analysis utilized a 2 × 2 (limb × brace) analysis of variance with a significant alpha level of 0.05. RESULTS: Subjects had increased knee flexion on the surgical side when they were braced. The brace condition increased knee flexion velocity, decreased the initial knee flexion angle, and increased the ground reaction force and knee extension moment on both limbs. Side-to-side asymmetry was present across conditions for the vertical ground reaction force and knee extension moment. CONCLUSION: Wearing a knee brace appears to increase lower extremity compliance and promotes normalized loading on the surgical side. CLINICAL RELEVANCE: Knee extension constraint bracing in postoperative ACL patients may improve symmetry of lower extremity mechanics, which is potentially beneficial in progressing rehabilitation and reducing the incidence of second ACL tears.

Time to get rid of the clock: intraobserver and interobserver reliability in determination of the o'clock position of the femoral tunnel in ACL reconstruction.

This study evaluates intraobserver and interobserver agreement in reporting the o'clock position of the femoral tunnel during anterior cruciate ligament (ACL) reconstruction. Four PGY2 residents, four PGY5 residents, and four sports medicine orthopedic surgeons reported the o'clock position of the femoral ACL tunnel in 10 arthroscopic pictures on two occasions 3 months apart. Intraobserver agreement was determined using the intraobserver correlation coefficient (r > 0.576 for 0.05 significance level). Interobserver agreement between members of each group and between reviewer groups was evaluated with the intraclass correlation coefficient (ICC > 0.75 considered good agreement). Poor interobserver agreement was demonstrated between the attending and PGY2 groups (ICC = 0.1685), between the attending and PGY5 groups (ICC = 0.2982), and between the PGY5 and PGY2 groups (ICC = 0.267). Attending surgeons, PGY5s, and PGY2s demonstrated poor interobserver agreement amongst themselves (ICC = 0.2244, 0.471, and 0.0859, respectively). PGY2s and PGY5s demonstrated good intraobserver agreement, but attending surgeons demonstrated poor intraobserver agreement. Attending orthopedic surgeons and residents of different levels of training interpret the o'clock position of the femoral tunnel differently. Greater years of experience does not improve intraobserver or interobserver agreement on the o'clock position. The clock face terminology for femoral tunnel placement may not be a reliable descriptor for scientific investigations or clinical instruction.

The effects of femoral graft placement on cartilage thickness after anterior cruciate ligament reconstruction.

Altered joint motion has been thought to be a contributing factor in the long-term development of osteoarthritis after ACL reconstruction. While many studies have quantified knee kinematics after ACL injury and reconstruction, there is limited in vivo data characterizing the effects of altered knee motion on cartilage thickness distributions. Thus, the objective of this study was to compare cartilage thickness distributions in two groups of patients with ACL reconstruction: one group in which subjects received a non-anatomic reconstruction that resulted in abnormal joint motion and another group in which subjects received an anatomically placed graft that more closely restored normal knee motion. Ten patients with anatomic graft placement (mean follow-up: 20 months) and 12 patients with non-anatomic graft placement (mean follow-up: 18 months) were scanned using high-resolution MR imaging. These images were used to generate 3D mesh models of both knees of each patient. The operative and contralateral knee models were registered to each other and a grid sampling system was used to make site-specific comparisons of cartilage thickness. Patients in the non-anatomic graft placement group demonstrated a significant decrease in cartilage thickness along the medial intercondylar notch in the operative knee relative to the intact knee (8%). In the anatomic graft placement group, no significant changes were observed. These findings suggest that restoring normal knee motion after ACL injury may help to slow the progression of degeneration. Therefore, graft placement may have important implications on the development of osteoarthritis after ACL reconstruction.

Tram-track appearance of the posterior cruciate ligament (PCL): correlations with mucoid degeneration, ligamentous stability, and differentiation from PCL tears.

OBJECTIVE: The purpose of our study was to describe the MRI findings in the posterior cruciate ligament (PCL) analogous to mucoid degeneration in the anterior cruciate ligament (ACL); to correlate MRI findings in the PCL with ligamentous stability; to differentiate the PCL tram-track appearance from the appearance of PCL tears; and to emphasize the coexistence of PCL and ACL mucoid degeneration, cruciate ganglia, and meniscal cysts. CONCLUSION: The tram-track PCL appearance commonly coexists with ACL mucoid degeneration; ganglia; and, less frequently, meniscal cysts. Both PCL tears and MRI findings suggestive of PCL mucoid degeneration show ligament thickening and increased PCL signal intensity. Tram-track PCLs are usually asymptomatic and typically have no ligamentous instability.

The Arthroscopic Surgical Skill Evaluation Tool (ASSET).

BACKGROUND: Surgeries employing arthroscopic techniques are among the most commonly performed in orthopaedic clinical practice; however, valid and reliable methods of assessing the arthroscopic skill of orthopaedic surgeons are lacking. HYPOTHESIS: The Arthroscopic Surgery Skill Evaluation Tool (ASSET) will demonstrate content validity, concurrent criterion-oriented validity, and reliability when used to assess the technical ability of surgeons performing diagnostic knee arthroscopic surgery on cadaveric specimens. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Content validity was determined by a group of 7 experts using the Delphi method. Intra-articular performance of a right and left diagnostic knee arthroscopic procedure was recorded for 28 residents and 2 sports medicine fellowship-trained attending surgeons. Surgeon performance was assessed by 2 blinded raters using the ASSET. Concurrent criterion-oriented validity, interrater reliability, and test-retest reliability were evaluated. RESULTS: Content validity: The content development group identified 8 arthroscopic skill domains to evaluate using the ASSET. Concurrent criterion-oriented validity: Significant differences in the total ASSET score (P < .05) between novice, intermediate, and advanced experience groups were identified. Interrater reliability: The ASSET scores assigned by each rater were strongly correlated (r = 0.91, P < .01), and the intraclass correlation coefficient between raters for the total ASSET score was 0.90. Test-retest reliability: There was a significant correlation between ASSET scores for both procedures attempted by each surgeon (r = 0.79, P < .01). CONCLUSION: The ASSET appears to be a useful, valid, and reliable method for assessing surgeon performance of diagnostic knee arthroscopic surgery in cadaveric specimens. Studies are ongoing to determine its generalizability to other procedures as well as to the live operating room and other simulated environments.

Intercondylar synovial septum in two patients with nail-patella syndrome.

This case report describes the arthroscopic findings in two patients with nail-patella syndrome (NPS). In both cases, a midline synovial septum was encountered that completely subdivided the knee into medial and lateral compartments. One patient required two subsequent arthroscopic procedures, and the synovial septum was found to have recurred even after it had been resected at the initial surgery. The etiology and clinical significance of this anatomic anomaly are unknown, however, surgeons should be aware of its existence and the potential difficulties it may present during knee arthroscopy in patients with NPS.