Long-term results of meniscal allograft transplantation.

Between May 1984 and December 1986, 23 patients with a history of medial meniscectomy and anterior knee instability were entered into a long-term prospective study of the results of medial meniscal transplantation combined with reconstruction of the anterior cruciate ligament. In 17 cases a lyophilized meniscal allograft was used and in 6 cases a deep-frozen meniscal allograft was used. The patients' clinical outcomes were evaluated 3 and 14 years postoperatively by clinical assessment, Lysholm score, radiographs, magnetic resonance imaging, arthrography, and, in some cases, arthroscopy. Two anterior cruciate ligament reconstruction control groups were used for comparison, one group having previously undergone meniscectomy and one with intact menisci. The follow-up rate was 100% after 14 years. The Lysholm score was 84 +/- 12 points at 3 years postoperatively and 75 +/- 23 points at 14 years. Patients with deep-frozen meniscal transplants generally had better results than patients with lyophilized meniscal transplants. Magnetic resonance imaging evaluation showed good preservation of the deep-frozen meniscal transplants, even after 14 years. The lyophilized meniscal transplants were reduced in size at the second-look arthroscopy and as seen on magnetic resonance imaging examination. When the control groups were compared with the study group, the deep-frozen meniscal allografts were found to be more comparable with an intact meniscus and the lyophilized meniscal allografts were more comparable with the control group knees that had undergone meniscectomy.