Medial and lateral meniscal tear patterns in anterior cruciate ligament-deficient knees. A prospective analysis of 575 tears.

We used our database to evaluate the locations of meniscal tears associated with anterior cruciate ligament injuries. Five hundred seventy-five meniscal tears were seen in 476 patients. Each tear was categorized prospectively according to the side (medial/lateral), the radial zone of the tear, and the circumferential zone of the tear. The different tear locations were then compared for the medial and lateral menisci and evaluated for statistical significance. We found a nearly equal number of tears on the medial (305) and lateral (270) sides. A significantly greater number of tears on the medial side as compared with the lateral side were posterior (99.4% versus 87.8%) and peripheral (75.4% versus 44.1%). Peripheral posterior horn tears of the medial meniscus were the most common type of tear (230 of 575, 40%) by a statistically significant amount.