Early Osteoarthritis After Untreated Anterior Meniscal Root Tears: An In Vivo Animal Study.

BACKGROUND: Meniscal root tears cause menisci and their insertions to inadequately distribute loads and potentially leave underlying articular cartilage unprotected. Untreated meniscal root tears are becoming increasingly recognized to induce joint degradation; however, little information is known about anterior meniscal root tears and how they affect joint tissue. PURPOSE: To observe the early degenerative changes within the synovial fluid, menisci, tibial articular cartilage, and subchondral bone after arthroscopic creation of untreated anterior meniscal root tears. STUDY DESIGN: Controlled laboratory study. METHODS: Anterolateral meniscal root tears were created in 1 knee joint of 5 adult Flemish Giant rabbits, and anteromedial meniscal root tears were created in 4 additional rabbits. The contralateral limbs were used as nonoperated controls. The animals were euthanized at 8 weeks postoperatively; synovial fluid was aspirated, and tissue samples of menisci and tibial articular cartilage were collected and processed for multiple analyses to detect signs of early degeneration. RESULTS: Significant changes were found within the synovial fluid, meniscal tissue, and tibial subchondral bone of the knees with anterior meniscal root tears when compared with controls. There were no significant changes identified in the tibial articular cartilage when comparing the tear groups with controls. CONCLUSION: This study demonstrated early degenerative changes within the synovial fluid, menisci, and tibial subchondral bone when leaving anterior meniscal root tears untreated for 8 weeks. The results suggest that meniscal tissue presents measurable, degenerative changes prior to changes within the articular cartilage after anterior meniscal root tears. Anterior destabilization of the meniscus arthroscopically may lead to measurable degenerative changes and be useful for future in vivo natural history and animal repair studies. CLINICAL RELEVANCE: The present study is the first to investigate various tissue changes after anterior meniscal root tears of both the medial and lateral menisci. The results from this study suggest that degenerative changes occur within the synovial fluid, meniscus, and tibial subchondral bone prior to any measurable changes to the tibial articular cartilage. Further studies should expand on this study to evaluate how these components continue to progress when left untreated for long periods.

Comprehensive Arthroscopic Management of Glenohumeral Osteoarthritis: Preoperative Factors Predictive of Treatment Failure.

BACKGROUND: Patient selection is critical when choosing between arthroscopic joint preservation and total shoulder arthroplasty in young patients with glenohumeral osteoarthritis (GHOA). PURPOSE: To identify prognostic factors predictive of early failure in patients undergoing comprehensive arthroscopic management (CAM) for GHOA. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: A total of 107 shoulders in 98 patients with minimum 2-year follow-up who underwent CAM were identified and evaluated. All shoulders met clinical and radiographic criteria for total shoulder arthroplasty (TSA), but the patients opted for joint preservation with arthroscopic management. Radiographic and preoperative factors were analyzed to determine predictors of early failure, defined as progression to TSA within the study period. RESULTS: There were 72 men and 26 women with a mean age of 52 years (range, 29-77 years). Seventeen (15.8%) of 107 shoulders progressed to TSA at a mean of 2 years (range, 0.46-8.2 years). Shoulder status for the rest had a mean follow-up of 3.9 years (range, 2-9.4 years). There were a number of radiographic features that were correlated with early failure. Patients who failed had significantly less preoperative joint space than did those who succeeded (1.3 vs 2.6 mm; P = .004). Higher Kellgren-Lawrence grades for osteoarthritis and age older than 50 were also associated with failure. Shoulders with Walch type B2 and C glenoid were significantly more likely to fail than were Walch types A1, A2, and B1 ( P < .05). CONCLUSION: The CAM procedure has been shown to reliably improve pain and function in active patients with advanced GHOA; however, it is important to inform patients about the limitations of the procedure. Patients with less joint space and abnormal posterior glenoid shape were significantly more likely to progress to early failure.

Anatomic Reconstruction of the Proximal Tibiofibular Joint.

Proximal tibiofibular joint (PTFJ) instability can be easily missed or confused for other, more common lateral knee pathologies such as meniscal tears, fibular collateral ligament injury, biceps femoris pathology, or iliotibial band syndrome. Because of this confusion, some authors believe that PTFJ instability is more common than initially appreciated. Patients with PTFJ subluxation may have no history of inciting trauma or injury, and it is not uncommon for these patients to have bilateral symptoms and generalized ligamentous laxity. Currently, the optimal surgical treatment for patients with chronic PTFJ instability is unknown. Historically, a variety of surgical treatments have been reported. Initially, joint arthrodesis and fibular head resection were recommended. More recently, temporary screw fixation, nonanatomic reconstruction with strips of the biceps femoris tendon or iliotibial band, and reconstruction with free hamstring autograft have been described. The purpose of this report is to present our surgical technique for treatment of chronic PTFJ instability using an anatomic reconstruction of the posterior ligamentous structures of the PTFJ with a semitendinosus autograft.

Comparison of fixation methods after anteromedialization osteotomy of the tibial tubercle for patellar instability.

PURPOSE: The aim of this study was to evaluate the biomechanical strength of two 4.5-mm screws and three 3.5-mm screws for fixation of the tibial tubercle after anteromedialization osteotomy. METHODS: Anteromedialization of the tibial tubercle was performed on 5 pairs of fresh-frozen cadaveric lower extremities. One leg from each pair was randomized to fixation with two 4.5-mm screws and the contralateral leg to fixation with three 3.5-mm screws. Each specimen was loaded cyclically to simulate an active straight-leg raise and then to failure while displacement of the tubercle fragment was recorded. RESULTS: There was no difference in mean tubercle fragment displacement under cyclic loading at any cycle number (P > .352). Maximum failure load for osteotomies secured with two 4.5-mm screws was 1,459 ± 540 N, and for three 3.5-mm screws it was 1,360 ± 707 N. This was not a statistically significant difference (P = .723). Tubercle migration of 7 mm was chosen as clinical failure. At this amount of displacement, mean load was 1,085 ± 398 N and 764 ± 313 N in the 4.5-mm and 3.5-mm groups, respectively, which was also not significantly different (P = .146). CONCLUSIONS: Both 2 × 4.5-mm and 3 × 3.5-mm screw constructs after tibial tubercle anteromedialization are equally capable of withstanding physiologic forces like those encountered during an active straight-leg raise and have similar failure strength. CLINICAL RELEVANCE: Although both configurations are comparable, the use of the smaller 3.5-mm screws may reduce the need for hardware removal related to prominence and soft tissue irritation.

Neural signatures of economic preferences for risk and ambiguity.

People often prefer the known over the unknown, sometimes sacrificing potential rewards for the sake of surety. Overcoming impulsive preferences for certainty in order to exploit uncertain but potentially lucrative options may require specialized neural mechanisms. Here, we demonstrate by functional magnetic resonance imaging (fMRI) that individuals' preferences for risk (uncertainty with known probabilities) and ambiguity (uncertainty with unknown probabilities) predict brain activation associated with decision making. Activation within the lateral prefrontal cortex was predicted by ambiguity preference and was also negatively correlated with an independent clinical measure of behavioral impulsiveness, suggesting that this region implements contextual analysis and inhibits impulsive responses. In contrast, activation of the posterior parietal cortex was predicted by risk preference. Together, this novel double dissociation indicates that decision making under ambiguity does not represent a special, more complex case of risky decision making; instead, these two forms of uncertainty are supported by distinct mechanisms.