Destruction of a cryopreserved meniscal allograft: A case for acute rejection

A cryopreserved nontissue-antigen-matched medial meniscus was transplanted arthroscopically into the knee of a 33-year-old cyclist. The patient had previously had an open medial menisectomy 19 years earlier and had significant symptoms. Ten weeks postoperatively, the patient underwent a second-look arthroscopy for a persistent effusion. Intraoperative cultures were obtained and all ultimately tested negative. The graft was found to be frayed throughout its length and significantly decreased in size. Its central portion had become detached from the peripheral repair while both the anterior and posterior bone blocks remained intact. Dense, inflammatory, hypertrophic synovium enveloped the entire joint. Histologically, the graft was found to be necrotic and acellular centrally, whereas the periphery was infiltrated with inflammatory leukocytes and giant cells. This histologic appearance is classical for an acute or subacute type rejection of allograft tissue.