[Transplantation of allogeneic menisci]

The increase in severe ligament injuries of the knee has led to consideration of the need for meniscal transplantation in reconstructive operations for chronic rotational instability. Transplantation of the medial meniscus was carried out in 30 sheep, which were divided up into 2 groups, each containing 15 sheep. In the first group lyophilized, y-sterilized allogeneic menisci were transplanted and these underwent complete remodelling in 48 weeks. In the other group, deep-frozen allogeneic menisci were used and these remained fully functional without remodelling. Twenty-three transplantations of the medial meniscus combined with replacement of the anterior cruciate ligament were performed from May 1984 to December 1986. Clinical follow-ups were coupled with arthroscopic follow-ups on an average of 10 months post-operatively in 19 sheep. In 17 cases a lyophilized meniscus was transplanted and in 6 cases a deep-frozen allogenous meniscus was used. There were no operation-specific complications in either group. Both the lyophilized meniscus transplants and the deep-frozen ones underwent a reduction in size during the observation period. Good-to-excellent results were generally obtained with the deep-frozen transplants; however, there is the risk of transmitting disease. The results seen in the lyophilized transplants were less satisfactory due to a reduction in size, sometimes down to the regeneration size. Taking the infrapatellar fatty pad for meniscal replacement (as suggested by Lexer), we saw only weak meniscus-like tissue after the first year postoperatively. The meniscus tendon by means of an autologous tendon for meniscus replacement may be an alternative procedure. Therefore, allogeneic meniscus transplantation for reconstruction of the knee joint cannot be recommended at present as a standard procedure.