Optimizing Meniscus Allograft Transplantation - Reducing Extrusion and Restoring Joint Loading Mechanics: A Systematic Review.

Abstract

Purpose of review: Meniscus allograft transplantation (MAT) is associated with good clinical outcomes even though biological mechanical and technical challenges persist. These include early graft shrinkage, extrusion, reoperation due to reoccurrence of pain or mechanical symptoms and progression of osteoarthritis (OA). The purpose of this review is to evaluate the influence of MAT surgical techniques, and novel cell therapies on graft extrusion and tibial femoral contact stresses and how these can be optimized to improve clinical outcomes.

Recent findings: Of the 27 articles that met the inclusion and exclusion criteria, 16 (clinical and cadaveric) focused on the impact of surgical fixation techniques on extrusion, joint loading mechanics and clinical outcomes. These studies demonstrated that bony fixation techniques were superior to soft tissue and transossesous suture fixation for restoring joint mechanics and minimizing extrusion. However, clinical outcomes were not significantly impacted by these biomechanical findings. The remaining 11 studies investigated novel cell therapies for meniscus regeneration and improving MAT procedures. Intrameniscal injections into frozen meniscus allografts demonstrated the potential for cell therapy to improve allograft tissue properties. Intraarticular injections and cell sheet transplantation led to tissue regeneration and chondroprotection following a hemi-meniscectomy in preclinical models. Although short-term clinical outcomes and PROMs are not significantly affected by fixation techniques, cadaveric and clinical studies have suggested that suture-only fixation with a traditional transosseous fixation may lead to worsened extrusion and joint mechanics compared to bony fixation methods. However, the implications of these findings on long-term clinical outcomes have not been evaluated. Cell therapy could further improve allograft tissue properties, chondroprotection and graft healing working together with current surgical techniques to restore joint functioning.