Review Question - QID 8615

The MRI scan shows a bone bruise of the lateral femoral condyle and lateral tibial plateau. This injury pattern is commonly associated with anterior cruciate ligament (ACL) rupture and an abnormal pivot shift test result. Treatment of an ACL tear in a high-demand athlete should consist of ligament reconstruction. In this patient, surgery should be delayed until she regains full range of motion to minimize risk for arthrofibrosis after surgery. Recent analysis has shown that the noncontact mechanism is more consistent with anterior translation, affecting both the medial and lateral compartments. The bone bruise in the lateral femoral condyle occurs more anterior than that of the medial femoral condyle, suggesting that internal rotation has occurred. The external rotation recurvatum test assesses for posterolateral corner injury, and a positive quadriceps active test is consistent with posterior cruciate ligament rupture. An abnormal patellar apprehension test result is suggestive of patellar instability. Nonsurgical treatment is unlikely to result in sufficient stability if this patient returns to sports at her preinjury level of activity. Primary ACL repair is associated with high failure rates. Although the precise mechanism of injury varies, injuries can be broadly classified into contact and noncontact injuries. Noncontact injuries occur with the knee in slight flexion, valgus, and internal rotation, and contact injuries typically involve a lateral-side impact producing a valgus force to the knee. The valgus component of noncontact injuries has been thought to cause mainly lateral compartment bone bruising. Posterior translation is the most common mechanism of posterior cruciate ligament rupture, and hyperextension and varus is associated with posterolateral corner injury.