Comparative Study on Immediate Versus Delayed Meniscus Allograft Transplantation

Background: Meniscus allograft transplantation (MAT) is generally used for patients who sustain symptoms after meniscectomy, which could be called delayed MAT. Meniscus allograft transplantation for patients immediately after meniscectomy has not been reported. Hypothesis: Compared with the conventional delayed MAT, immediate MAT might provide better clinical results and reduce joint degeneration. Study Design: Cohort study; Level of evidence, 3. Methods: The study was performed with 18 transplanted menisci (6 medial, 12 lateral) from 16 patients. Eight menisci were transplanted immediately after meniscectomy (IM group); 10 menisci, from patients who complained of knee symptoms at a mean time of 35 months (range, 9-92 months) after total meniscectomy, underwent delayed transplantation (DE group). Fourteen patients undergoing meniscectomy during the same period were included as controls (ME group). Degenerative changes in knee joints were evaluated by plain radiographs and magnetic resonance imaging (MRI). Allograft extrusion and relative percentage of extrusion were measured on MRI. Other outcome assessments included preoperative and postoperative International Knee Documentation Committee (IKDC), Tegner, and Lysholm scores; visual analog scale (VAS) for pain; and range of motion and isokinetic muscle strength evaluation. Results: The mean length of follow-up was 50.8 months (range, 44-62 months) for the IM group, 72.0 months (range, 44-94 months) for the DE group, and 54.3 months (range, 45-62 months) for the ME group. A statistically significant difference in favor of the IM and ME groups was found on the VAS (0.4 [IM group] vs 1.1 [ME group] vs 2.5 [DE group]) and muscle strength ( P < .05). The mean IKDC score in the IM group was significantly higher than that in the DE group (93 [range, 85-99] vs 74 [range, 38-95], respectively; P < .05). The IM group showed significantly less preoperative to postoperative cartilage degeneration changes on radiographs and MRI when compared with the DE and ME groups (Kellgren-Lawrence score changes: 0.25 [IM group] vs 1.0 [DE group] vs 1.7 [ME group]; Yulish score changes: 0.25 [IM group] vs 1.0 [DE group] vs 1.1 [ME group]; P < .05). Extrusion of the allograft was observed in the body of the menisci in all patients. No significant difference was found in terms of the Lysholm score, Tegner score, joint narrowing, or meniscus extrusion ( P > .05). Conclusion: Compared with delayed MAT, immediate MAT led to more satisfactory subjective results, less joint degeneration, and less muscle strength deficits. The short-term results of delayed meniscus transplantation were close to those of meniscectomy.