Revision Meniscal Allograft Transplantation in the Lateral Compartment

Abstract

Background: Little is known about clinical outcomes after revision meniscal allograft transplantation (RMAT), and there are no studies on magnetic resonance imaging (MRI) evaluations during the early remodeling period. Hypothesis: The objective imaging results, as determined by MRI evaluation, would be inferior to those of published data on primary meniscal allograft transplantations (MATs), although short-term clinical improvement would be achieved after RMAT. Study Design: Case series; Level of evidence, 4. Methods: We retrospectively reviewed 9 consecutive patients (6 male and 3 female) who underwent RMAT from 2010 to 2014. The mean patient age was 33 years (range, 28-45 years). All patients had prior failed MATs in the lateral compartment. None of the patients had malalignment or ligament instability, and 7 patients had grade 3 or higher chondral degeneration. We assessed the RMAT with routine MRI evaluations during the remodeling period of the first postoperative year to determine graft healing and the mode of refailures, if any. We also investigated the problems specific for revision operations, as well as clinical outcomes. Results: Four of the 9 RMAT patients had significant intra-articular fibrosis with or without motion limitations at the time of RMAT. MRI evaluations demonstrated that the overall early refailure rate was 33.3% (3/9) during the first year; bucket-handle displacement with no meniscocapsular healing was the mode of all failures. Insufficient meniscal healing was also found in 2 other RMATs without premature failure. After a mean follow-up of 29.2 months (range, 21-45 months) in the 6 patients with preserved RMATs, Lysholm and International Knee Documentation Committee subjective scores showed significant improvements over preoperative scores (from 53.3 ± 6.0 to 87.7 ± 2.9 [P = .028] and from 53.4 ± 9.0 to 69.9 ± 4.8 [P = .043], respectively; Wilcoxon signed rank test). Conclusion: The MRI findings showed that poor or insufficient meniscal healing to the host joint capsule was the major drawback of RMAT. Although more than half of our patients experienced clinical improvement after RMAT, the short-term graft survival was inferior to that of primary MATs in the literature. Our findings suggest that this challenging revision procedure requires great caution, especially with regard to the effects of poor host tissue quality on meniscal healing. Although RMAT can be an effective treatment, close observation with routine MRI evaluation is necessary during the early remodeling period to assess the status of the revised meniscal allograft.