Review Question - QID 5929

The patient has sustained a tear of his anterior cruciate ligament (ACL), as demonstrated by the positive pivot shift test; therefore, he would most likely exhibit lateral joint line tenderness indicative of a lateral meniscus tear, the most common intraarticular injury associated with an ACL tear.

ACL tears usually occur as a result of a non-contact pivoting injury. Abnormal anterior translation results in bone contusions of mid-lateral femoral condyle and posterolateral tibia, which can be seen on MRI. Other concomitant intraarticular injuries include meniscal tears (lateral > medial), chondral damage and other ligamentous injury (MCL, LCL, PLC) usually found in cases of higher energy trauma such as a knee dislocation.

Piasecki et al prospectively analyzed intraarticular injuries associated with ACL tears in high school athletes by gender and sport. There was no significant difference in mechanism of injury between sexes. Female basketball and soccer players had fewer intraarticular injuries (medial femoral condyle lesions, medial and lateral meniscus tears) compared to male athletes. The authors hypothesized that women may therefore enjoy a better prognosis following reconstruction.

Spindler et al performed a prospective cohort study investigating concomitant intraarticular injuries in patients who underwent ACL reconstruction. Eighty percent of patients had a bone bruise on MRI, 68% involving the lateral condyle. At time of arthroscopic reconstruction, meniscal tears were identified in 56% of lateral menisci and 37% of medial menisci.

Incorrect Responses:
Answer 1: Medial joint line tenderness is suggestive of a medial meniscus tear, which is a common injury associated with ACL tears but is less common than a lateral meniscus tear in cases of acute ACL rupture. Medial meniscus tears are more common in chronic ACL tears.
Answer 3: Positive dial test at 30° of knee flexion is suggestive of a posterolateral corner injury, which is less common than a lateral meniscus tear in patients with an ACL tear.
Answer 4: Varus laxity at 30° of knee flexion is suggestive of a lateral collateral ligament injury, which is less common than a lateral meniscus tear in patients with an ACL tear.
Answer 5: Positive posterior drawer test is suggestive of a posterior cruciate ligament injury, which is less common than a lateral meniscus tear in patients with an ACL tear.