Good clinical outcomes can be expected after meniscal allograft transplantation at 15 years of follow-up

Purpose The aim of this study was to evaluate graft survivorship and report the functional and radiographic results of Meniscal allograft transplantation (MAT) throughout a minimum 15-year follow-up period. Methods Fifty-one patients that had undergone an isolated MAT procedure during the period studied were included. The results were assessed with the Lysholm and Tegner scores as well as the Visual Analog Scale. Magnetic resonance imaging and a complete radiographic series were carried out to determine the degree of meniscal extrusion and joint space narrowing. A comparison was made between the radiological findings of the last follow-up, the 5-year mid-term follow-up and those from the preoperative period. Results Thirty-eight patients were available for the final follow-up. The mean follow-up was 17.4 years. There were 23 (60.5%) medial menisci and 15 lateral menisci (39.4%). Meniscal extrusion increased from the 29.7% +/- 14.9 obtained at the 5-year follow-up to the 72.5% +/- 22.5 seen at the end of the follow-up (p = 0.0001). The joint space distance was almost unchanged from the initial evaluation (3.3 +/- 1.5 mm) to the 5-year follow-up measurement (3.1 +/- 1.7 mm, n.s.). However, it did decrease at the last follow-up (1.9 +/- 1.5 mm, p < 0.05). The functional outcomes improved from the preoperative period to the mid-term follow-up and later worsened at the final follow-up. The mean preoperative Lysholm score at the initial follow-up was 61.5 +/- 9.6, 86.9 +/- 10.9 for the 5-year evaluation and stood at 77.4 +/- 11.5 (p = 0.0001) at the final follow-up. Regarding the Tegner score, those pre-operative scores were compared to the ones at the last follow-up (median: 3; range 0-6 vs. 5.5; 3-6, respectively; p = 0.0001). The VAS went down from 6.6 +/- 1.7 at the initial evaluation to 2.5 +/- 1.9 at the final follow-up (p = 0.0001). The joint-space width remained unchanged from the initial evaluation (3.35 +/- 1.5 mm) up to the 5-year follow-up measurement (3.1 +/- 1.7 mm, n.s.). However, this joint-space distance had decreased by the last evaluation in the long-term follow-up (1.9 +/- 1.4 mm, p < 0.05). Five patients (13.1%) presented with a MAT failure at 5 years, which was followed by extirpation of the meniscal graft. At the final follow-up, a total of 16 patients (42.1%) presented with a failure. At that time, there were 4 more MAT removals and seven patients that required a total knee replacement. The mean time to failure of the meniscal graft was 206.2 months +/- 13.4 (18.0 years). Conclusions Meniscal allograft transplantation produces good functional results at a minimum 15-year follow-up. However, degenerative arthritis in the affected compartment progressed during that period.