Laser subtotal meniscectomy in rabbits.

This study investigates the healing potential of the peripheral rim of rabbit meniscus following laser subtotal meniscectomy. Thirty animals were operated with 23 bilateral meniscectomies and 7 sham controls. When sacrificed at intervals up to 6 months, the harvested peripheral rims demonstrated a devitalized layer of fibrocartilage averaging 17 micron in thickness, indicating an extremely superficial thermal effect of the laser energy utilizing power densities of 20 to 38 W. Viable chondrocytes and minimal alteration of collagen fibril structure and orientation were noted within 20 to 50 micron of the meniscus free margin. By 2 weeks, a proliferation of vascular buds near the free margin of the meniscus was observed with an increase in ground substance production and chondrocyte population. By 10 weeks, the free margin was completely sealed and was composed of logically oriented collagen fibers and only slightly increased numbers of chondrocytes. It was concluded that the healing potential of rabbit meniscus is unimpaired following laser resection of the central margin, and that the repair process is mediated by a proliferation of chondrocytes, supported in part by neovascularity within the substance of the meniscus.