Comparison of ACL Strain in the MCL-Deficient and MCL-Reconstructed Knee During Simulated Landing in a Cadaveric Model.

BACKGROUND: Noncontact anterior cruciate ligament (ACL) injury after valgus landing has been reported and studied biomechanically. However, the role of the medial collateral ligament (MCL) in dissipating these forces has not been fully elucidated. Purpose/Hypothesis: The purpose of this study was to investigate the role that the MCL plays in ACL strain during simulated landing. The hypothesis was that ACL strain would increase significantly in MCL-incompetent knees compared with the native knee and that reconstructing the MCL would return the values to those of the intact knee. STUDY DESIGN: Controlled laboratory study. METHODS: Eight fresh-frozen human cadaveric knees were used in this study. A materials testing machine applied a force of 2× body weight over 60 milliseconds to simulate landing after a jump. The knees were tested in 12 loading conditions, consisting of full extension or 15° of flexion combined with 7° of valgus or neutral alignment while the tibia was in external rotation, neutral rotation, or internal rotation. This test procedure was repeated on each specimen with the MCL transected and reconstructed. The superficial and deep MCL was transected along with the posterior oblique ligament, which was thought to simulate a worst case scenario. The MCL was reconstructed by use of semitendinosus and gracilis tendon grafts. RESULTS: During internal rotation at 0° of flexion and 0° of valgus, both the intact ( P = .005) and the reconstructed ( P = .004) MCL states placed significantly lower strain on the ACL than did the transected MCL. The reconstructed MCL state at 0° of flexion and 7° of valgus ( P = .049) along with 15° of flexion and 0° of valgus ( P = .020) also placed significantly lower strain on the ACL than did the transected MCL. For external rotation testing at 0° of flexion and 7° of valgus, the reconstructed MCL state placed significantly lower strain on the ACL than did the transected MCL ( P = .039). Finally, during neutral rotation, the ACL strain at 0° of valgus and 0° of flexion, and at 7° of valgus and 0° of flexion was significantly lower for the MCL-intact groups ( P < .028) and MCL-reconstructed groups ( P < .016) than the MCL-transected groups. CONCLUSION: The current findings demonstrate that during valgus landing, a knee with an incompetent MCL puts the ACL under increased strain. These values are highest in full extension with the tibia in internal and neutral rotation. This increased strain can be reduced to baseline levels with reconstruction. CLINICAL RELEVANCE: A knee with an incompetent MCL puts the ACL under increased strain. Once the MCL has healed in an elongated manner, MCL reconstruction should be considered.

When do rotator cuff repairs fail? Serial ultrasound examination after arthroscopic repair of large and massive rotator cuff tears.

BACKGROUND: Despite advances in arthroscopic repair of rotator cuff tears, recurrent tears after repair of large and massive tears remain a significant clinical problem. The primary objective of this study was to define the timing of structural failure of surgically repaired large and massive rotator cuff tears by serial imaging with ultrasound. The secondary objective of this study was to investigate the association between recurrent tears and clinical outcome after rotator cuff repair. HYPOTHESIS: Recurrent tear after arthroscopic repair of large rotator cuff tears is more likely to occur late (>3 months) in the postoperative period and will be associated with inferior clinical outcome scores. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Twenty-two consecutive patients with large (>3 cm) rotator cuff tears underwent arthroscopic repair with a standardized technique. Serial ultrasound examinations were performed at 2 days, 2 weeks, 6 weeks, 3 months, 6 months, 12 months, and 24 months after surgery. Western Ontario Rotator Cuff (WORC) Index scores were also collected at these time points. RESULTS: Nine (41%) of the 22 arthroscopically repaired rotator cuff tears demonstrated recurrent tears. Seven of the 9 retears occurred within 3 months of surgery, and the other 2 occurred between 3 and 6 months. No retears occurred after 6 months. At 24-month follow-up, WORC scores favoring intact rotator cuffs over retears approached statistical significance (mean WORC intact 123.9 vs retear 659.8; P = .07). CONCLUSION: Recurrent rotator cuff tears are not uncommon after arthroscopic repair of large and massive tears. These recurrent tears appear to occur more frequently in the early postoperative period (within the first 3 months) and are associated with inferior clinical outcomes.

Single-bundle versus double-bundle posterior cruciate ligament reconstruction.

PURPOSE: The purpose of this report is to present a systematic review of the literature to compare knee kinematics and clinical outcomes after single-bundle versus double-bundle posterior cruciate ligament reconstruction. METHODS: Systematic review of the literature by PubMed search, reference review, and search of Arthroscopy identified the relevant biomechanical and clinical studies. The studies were critically evaluated to determine potential advantages of single-bundle or double-bundle reconstructions in anteroposterior stability, graft tension, rotational stability, and functional outcome. RESULTS: Biomechanical comparisons evaluating anteroposterior stability described either no difference or increased stability with double-bundle reconstructions. Comparing these results is complicated by differential graft choices, tensioning techniques, and tunnel anatomy. Biomechanical studies of graft tension describe conflicting results regarding the optimal reconstruction technique. Recent studies of rotational stability suggest no advantage of double-bundle reconstruction in the setting of concomitant posterolateral corner repair but suggest a possible advantage in the setting of subtle posterolateral corner injury. Three retrospective clinical studies of single- and double-bundle reconstructions with methodologic limitations described no difference in clinical outcome. CONCLUSIONS: The superiority of single-bundle or double-bundle posterior cruciate ligament reconstruction remains uncertain.

The use of locked plating in skeletally immature patients.

The philosophy and techniques for the management of fractures in the pediatric patient have changed over the past several decades. The immature skeleton has unique properties, and injuries in children have different characteristics, management options, and complications than do similar injuries in adults. The basic surgical techniques used in the management of pediatric fractures include closed reduction and casting, closed or open reduction with internal fixation, and external fixation. The concept of bridging plate osteosynthesis has evolved based on scientific insight into bone biology and the importance of blood supply to bone. The use of locked plating is gaining favor in the treatment of certain fractures in adults. However, the role for this technique in the skeletally immature patient has not been described.