Fifty-four patients with anterior cruciate ligament tears that were arthroscopically reconstructed within 3 months of initial injury were prospectively evaluated. Patients with grade 3 medial collateral ligament, lateral collateral ligament, or posterior cruciate ligament tears were excluded. Eighty percent of our patients had a bone bruise present on the magnetic resonance image, with 68% in the lateral femoral condyle. Two of the latter findings--an abnormal articular cartilage signal (P = 0.02) and a thin and impacted subchondral bone (P = 0.03)--had a significant relationship with injury to the overlying articular cartilage. Meniscal tears were found in 56% of the lateral menisci and 37% of the medial menisci. A significant association was present between bone bruising on the lateral femoral condyle and the lateral tibial plateau (P = 0.02). Results of our study support the concept that the common mechanism of injury to the anterior cruciate ligament involves severe anterior subluxation with impaction of the posterior tibia on the anterior femur. Determination of the significance of bone bruising, articular cartilage injury, or meniscal tears will require a long-term followup that includes evaluation for arthritis, stability, and function. These 54 patients represent the first cohort evaluated in this ongoing prospective clinical study.

The purposes of this study were to determine the effect of a rigid ankle orthosis (Aircast Air-Stirrup) and lateral ankle ligament anesthesia on ankle joint proprioception. Twelve noninjured subjects attempted to match nine reference ankle joint positions with their eyes closed before and after application of the ankle brace and before and after one or two of the lateral ankle ligaments (anterior talofibular and calcaneofibular) were anesthetized. Three-dimensional ankle joint orientations were recorded with a Motion Analysis system. No significant differences in the constant, variable, or absolute error were seen between subjects in the non-anesthetized and anesthetized conditions (P > 0.05), regardless of whether one or two ligaments were anesthetized. Thus, it appears that ligament mechanoreceptors contributed little to ankle joint proprioception, and that the afferent feedback from skin, muscle, and other joint receptors was adequate for the positioning task of the present study. Both the variable and absolute error in matching the reference positions were significantly less with the orthosis than without (P < 0.05). Application of an orthosis may increase the afferent feedback from cutaneous receptors in the foot and shank, which may in turn lead to an improved ankle joint position sense.

A review of 250 cases of surgical reconstruction of the anterior cruciate ligament identified 24 patients with bilateral complete tears of the anterior cruciate ligament. Twenty of these patients had previous reconstruction of one anterior cruciate ligament before rupture of the opposite ligament. Twelve injuries occurred during the same activity that was responsible for the initial opposite injury. The average time between surgical reconstruction and rupture of the opposite ligament was 29.3 months (range, 3 to 103). No significant demographic differences existed between patients with unilateral or bilateral ruptures of the anterior cruciate ligament. Standardized measurements of intercondylar notch height and width and medial and lateral femoral condyle height and width were performed on routine notchview height and width were performed on routine notchview radiographs of 31 knees of patients with bilateral injuries, 30 with unilateral injury, and 30 with no anterior cruciate ligament injury. Statistical analysis revealed no significant differences between the three groups when comparing absolute measures or any of eight mathematical ratios calculated from these measurements. We concluded that measurements of the intercondylar notch made from radiographs may not be reliable predictors of injury to the anterior cruciate ligament. We found no significant clinical or demographic differences between patients with unilateral or bilateral complete ruptures of the anterior cruciate ligament.