Meniscal allograft transplantation: a systematic review

Background: Meniscal allograft transplantation (MAT) was developed as a means of treating the symptoms of compartmental overload after meniscectomy. Despite more than 20 years of research in this field, many controversies still exist regarding meniscal transplantation.Purpose: The aims of this study were to assess (1) the quality of the published studies on MAT; (2) the indications for this type of surgery; (3) the methods used for preservation, sizing, and fixation of the allograft; and (4) the clinical and radiographic outcomes of this procedure and its role in preventing osteoarthritis.Study Design: Systematic review.Methods: Inclusion criteria for the articles were (1) English language, (2) peer-reviewed clinical studies with evidence levels 1 to 4, (3) reported clinical and/or radiological outcomes of MAT isolated or combined with other procedures, (4) minimum 12-month follow-up, (5) case series of at least 10 patients, and (6) a follow-up rate of at least 80% (no more than 20% of patients lost to follow-up).Results: A total of 55 studies matched the inclusion criteria (2 level 2, 7 level 3, and 46 level 4). The average Coleman methodology score was 49.73 12.41 (range, 24-81). There was agreement in the literature regarding the indications for MAT: joint line pain and tenderness correlated with previous meniscectomy, young patients, without diffuse Outerbridge grade III and no grade IV cartilage damage, and a stable and well-aligned knee. Different graft types have been used: viable, fresh frozen, cryopreserved, and lyophilized. The most common method for graft sizing was plain radiography. Different fixation techniques have been described, with only a few studies comparing the clinical results of the different techniques and with no proven superiority of one method over the other. All the studies showed clinical improvement at last follow-up visit compared with preoperatively. The chondroprotective effect of MAT is still unclear.Conclusion: Meniscal allograft transplantation seems to provide good clinical results at short-term and midterm follow-up, with improvement in knee function as well as acceptable complication and failure rates. Higher quality studies are necessary to better assess the potential chondroprotective effect of MAT and to identify differences in terms of outcomes between different surgical techniques.