No abstract

Background Anatomic double-bundle reconstruction has been thought to better simulate the anterior cruciate ligament anatomy. It is, however, a technically challenging procedure, associated with longer operation time and higher cost. Hypothesis Double-bundle anterior cruciate ligament reconstruction using a single femoral and tibial tunnel can closely reproduce intact knee kinematics. Study Design Controlled laboratory study. Methods Eight fresh-frozen human cadaveric knee specimens were tested using a robotic testing system to investigate the kinematic response of the knee joint under an anterior tibial load (130 N), simulated quadriceps load (400 N), and combined torques (5 N·m valgus and 5 N·m internal tibial torques) at 0°, 15°, 30°, 60°, and 90° of flexion. Each knee was tested sequentially under 4 conditions: (1) anterior cruciate ligament intact, (2) anterior cruciate ligament deficient, (3) single-bundle anterior cruciate ligament reconstruction using quadrupled hamstring tendon, and (4) single-tunnel–double-bundle anterior cruciate ligament reconstruction using the same tunnels and quadrupled hamstring tendon graft as in the single-bundle anterior cruciate ligament reconstruction. Results Single-tunnel–double-bundle anterior cruciate ligament reconstruction more closely restored the intact knee kinematics than single-bundle anterior cruciate ligament reconstruction at low flexion angles (≤30°) under the anterior tibial load and simulated muscle load (P < .05). However, single-tunnel–double-bundle anterior cruciate ligament reconstruction overconstrained the knee joint at high flexion angles (≥60°) under the anterior tibial load and at 0° and 30° of flexion under combined torques. Conclusion This double-bundle anterior cruciate ligament reconstruction using a single tunnel can better restore anterior tibial translations to the intact level compared with single-bundle anterior cruciate ligament reconstruction at low flexion angles, but it overconstrained the knee joint at high flexion angles. Clinical Relevance This technique could be an alternative for both single-bundle and double-tunnel–double-bundle anterior cruciate ligament reconstructions to reproduce intact knee kinematics and native anterior cruciate ligament anatomy.

No abstract

No abstract

Study Design: Prospective cohort study. Objectives: To determine the effect of rotator cuff tear size on shoulder strength and range of motion. Background: Patients with rotator cuff pathology typically present with weakness and motion loss in various motions. The extent to which the presence of a rotator cuff tear and the size of the tear affect strength and range of motion is not well understood. Methods and Measures: Sixty-one patients scheduled for surgery, with a diagnosis of a rotator cuff tear and/or subacromial impingement, underwent examination for shoulder pain, function, range of motion, and strength. The extent of rotator cuff pathology was documented during subsequent surgery (presence of tear, tear size, tear thickness). Results: There were 10 massive tears, 15 large tears, 13 medium tears, 12 small tears, and 11 rotator cuffs without a tear. Patients had marked weakness in abduction strength at 90°and 10°of abduction, in external rotation strength at 90°, and in the ''full can test'' (all, P Ͻ.0001). Marked range of motion losses in shoulder flexion and external rotation at 0°and 90°abduction (all, P Ͻ.001) were also observed. Abduction strength deficit at 10°was affected by rotator cuff tear size (P Ͻ.0001). Twenty of 25 patients with large or massive tears had deficits greater than 50%, compared with only 1 of 11 patients with no tear, 2 of 12 patients with a small tear, and 5 of 13 patients with a medium tear (P Ͻ.0001). Other strength and range of motion deficits or indices of pain and function were unaffected by tear size. Conclusions: Weakness of greater than 50% relative to the contralateral side in shoulder abduction at 10°of abduction was indicative of a large or massive rotator cuff tear. J Orthop Sports Phys Ther 2005;35:130-135.