While studies have shown significant clinical improvement after medial meniscus allograft transplantation (MMAT) with good long-term graft survivorship, progression to osteoarthritis still occurs, even in the presence of intact grafts. Several factors can potentially explain the lack of chondroprotection despite graft survivorship, including meniscal degeneration, tearing, and remodeling after the initial procedure. A major factor contributing to progression of osteoarthritis is meniscal extrusion, which is seen in up to 60% of patients and seems to be more of an issue in medial meniscus transplantation compared to lateral and is present even immediately postoperatively. Grafts without extrusion provide protective effects similar to the native meniscus, while greater than 3 mm of extrusion leads to nearly complete loss of the protective effects. A reconstruction of the meniscotibial ligament, in addition to standard MMAT, may significantly decrease meniscal extrusion. Optimization of graft size, quality, and meniscal root positioning is best to prevent extrusion and restore native biomechanics.
Copyright © 2022 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.