Survivorship After Meniscal Allograft Transplantation According to Articular Cartilage Status

Clinical outcomes after meniscal allograft transplantation (MAT) in arthritic knees are unclear, and objective estimates of graft survival according to the articular cartilage status have not been performed.

MAT should provide clinical benefits in knees with high-grade cartilage damage, but their graft survivorship should be inferior to that in knees with low-grade chondral degeneration after MAT.

Cohort study; Level of evidence, 3.

The records of 222 consecutive patients who underwent primary MAT were reviewed to compare clinical outcomes and graft survivorship. The patients were grouped according to the degree and location of articular cartilage degeneration: low-grade chondral lesions (International Cartilage Repair Society [ICRS] grade ≤2) on both the femoral and tibial sides (ideal indication), high-grade lesions (ICRS grade 3 or 4) on either the femoral or tibial side (relative indication), and high-grade lesions on both sides (salvage indication). Kaplan-Meier survival analysis with the log-rank test was performed to compare the clinical survival rates and graft survival rates between the groups. A Lysholm score of <65 was considered a clinical failure, and graft failure was defined as a meniscal tear or meniscectomy of greater than one-third of the allograft, objectively evaluated by magnetic resonance imaging (MRI) and second-look arthroscopic surgery.

The mean (±SD) Lysholm score significantly improved from 63.1 ± 15.1 preoperatively to 85.1 ± 14.3 at the latest follow-up of a mean 44.6 ± 19.7 months ( P < .001). However, the postoperative scores were not significantly different between the 3 groups (85.7 ± 14.2 for ideal indication, 84.7 ± 17.0 for relative indication, and 84.7 ± 14.2 for salvage indication; P = .877). On MRI at the latest follow-up of a mean 23.0 ± 19.9 months and second-look arthroscopic surgery of a mean 19.3 ± 20.7 months, there were 25 (11.3%) failed MAT procedures (4 medial, 21 lateral); of these, 5 lateral MAT procedures (2.3%) went on to allograft removal. Clinical survival rates were not significantly different between the groups ( P = .256). However, on objective evaluation, the estimated cumulative graft survival rate at 5 years in the salvage indication group (62.2% [95% CI, 41.6-82.8]) was significantly lower than that in the other 2 groups (ideal indication: 93.8% [95% CI, 88.5-99.1]; relative indication: 90.9% [95% CI, 81.1-100.0]) ( P = .006).

Our findings showed that MAT was an effective symptomatic treatment in knees with advanced bipolar chondral lesions. However, better graft survival can be expected when articular cartilage is intact or if chondral damage is limited to a unipolar lesion. MAT should be considered before the progression of chondral damage to a bipolar lesion for better graft survivorship and should be performed cautiously in arthritic knees.