Meniscal transplantation using fresh and cryopreserved allografts

Abstract

A comparative study of three subgroups of meniscal transplants was undertaken in the goat model: Group 1 (autograft) involved removal and immediate reimplan tation of the meniscus; Group 2, fresh meniscal allo grafts ; and Group 3, cryopreserved (30 days) meniscal allografts. Six months after surgery, tissues were eval uated for gross degenerative changes, proteoglycan concentration (as assessed by uronic acid), water con tent, vascularity, histology, and cell viability. The con tralateral knee served as control for all comparisons. There was no statistical difference in the amount of arthritis present and all transplants demonstrated an essentially normal peripheral vascularity compared to controls. Sections revealed reduced numbers of cells in the central portions of the transplanted menisci and these viable cells demonstrated different behavior in multiplication in tissue culture compared to contralateral controls. Grossly and microscopically, the implanted menisci differed little from the controls. The measurement of proteoglycan concentration and water content of the transplanted meniscal cartilage suggest alterations that may affect the long-term mechanical properties. The autograft specimens showed the water content was very slightly increased (3% to 6%), while the proteogly can concentration was increased (42% in terms of uronic acid). In contrast, the water content of the fresh allograft group and the cryopreserved group was in creased 12% to 24%. Proteoglycan concentration in these groups was decreased up to 56% in portions of some menisci compared to controls. Fresh and cryopreserved meniscal allografts showed peripheral healing, revascularization, cellularity, and in corporation, and grossly appeared good at 6 months in the goat model. The biochemical changes in the extra cellular matrix at 6 months raises questions on the long- term function of these transplanted menisci.