Purpose: We report the results of cryopreserved meniscus allograft transplantations with 10 or more years of follow-up.
Methods: Fourteen medial and 8 lateral meniscus allografts were evaluated with a mean follow-up of 141 months (range, 115 to 167 months). The clinical outcome and failure rate was evaluated by use of a Lysholm score and modified pain score in 22 patients. The results of radiographic and magnetic resonance imaging (MRI) analysis were reported in 15 and 7 patients, respectively.
Results: Overall, 25% of medial allografts and 50% of lateral allografts failed. The combined failure rate was 35%. There was a 90% improvement in Lysholm scores, as well as pain scores. There were no discernible Lysholm or pain score differences for both lateral and medial allografts. Furthermore, there was no discernible difference in both Lysholm and pain scores between bone plug and soft-tissue methods of graft fixation. Ten of fifteen allografts showed radiographic joint space narrowing, and twelve had progression of degenerative joint disease. On MRI, all grafts had moderate meniscus shrinkage and five had grade III signal intensities. Eighty-five percent of patients underwent subsequent procedures, 5 of whom required total allograft resection and 2 of whom required partial allograft resection. One allograft required repair.
Conclusions: Although transplantation of cryopreserved allografts improved knee pain and function, the average knee function was fair at long-term follow-up. Fifty-five percent of allografts failed when failure criteria for second-look surgery, knee improvement surveys, and MRI were added to Lysholm and pain score failures. The protective benefits of meniscus allografts remain debatable, and inferences cannot be made from this study.
Level of evidence: Level IV, therapeutic case series.