Meniscal repair. An experimental study in the goat

To evaluate the healing potential of the meniscus, we created a longitudinal medial meniscal tear in both knees of 24 adult goats (48 knees). In all goats, the meniscus was repaired in one knee and left unrepaired in the other. The goats were placed into one of three groups based on the location of the tear and the status of the anterior cruciate ligament. At 6 months' followup, an arthrogram was obtained and the menisci were examined. In knees with an intact anterior cruciate ligament, tears in the peripheral 20% to 25% of the meniscus healed in six of seven repaired menisci, but in only one of seven of the unrepaired menisci. Tears in the peripheral 40% to 50% healed in only one of the eight repaired menisci and in none of the unrepaired menisci. When the anterior cruciate ligament was incised, tears in the peripheral 20% to 25% of the meniscus healed in only 1 of 8 repaired menisci and in none of the unrepaired menisci; the rest developed into complex tears. Arthrography was 92% accurate in predicting the status of meniscal repair. This study supports current clinical practices in meniscal repair and emphasizes the importance of tear location and knee stability in successful meniscal repair.