COMPARISON OF COLLAGEN-SYNTHESIS IN THE PERIPHERAL AND CENTRAL REGIONOF THE CANINE MENISCUS

A comparison of collagen synthesis in the peripheral and central regio ns of the normal medial meniscus, the normal lateral meniscus, and the medial meniscus, three months after reconstruction of the anterior cr uciate ligament (ACL), was performed in a canine model. Triangular-sha ped explants were labeled in vitro with tritiated proline to compare c ollagen synthesis. Regional cellularity was also quantified. In the no rmal medial and lateral meniscus, cellularity was similar. Total colla gen synthesis, as assessed by collagenase digestible material, was sig nificantly elevated in the peripheral one-third of the medial meniscus versus the central region (paired t-test, p = 0.026). However, in the medial meniscus after ACL reconstruction, cellularity and total colla gen synthesis were significantly higher in the peripheral one-third ve rsus the contiguous central region. They were also elevated relative t o the peripheral and central region of the normal medial and lateral m eniscus (ANOVA, p < 0.05; Student-Neuman-Kuel test, p < 0.05). Thus, i n the normal medial meniscus, the peripheral one-third may have an inc reased healing potential based on its increased ability to synthesize collagen. Furthermore, after ACL reconstruction, only the peripheral, and not the central, region of the canine meniscus responds to the alt ered mechanical and synovial environment by significantly increasing c ellularity and collagen synthesis.