Is meniscal allograft transplantation chondroprotective? A systematic review of radiological outcomes.

PURPOSE: The primary aim of this systematic review was to examine the hypothesis that meniscal allograft transplantation is chondroprotective by identifying and appraising studies that have assessed the progression of osteoarthritis following meniscal allograft transplantation. The secondary aim was to identify and appraise radiological measures of meniscal allograft integrity following surgery. METHODS: Clinical studies on human participants undergoing meniscal allograft transplantation with a minimum follow-up of 6 months were included. The primary outcome measure was any radiological osteoarthritis progression measure. Secondary outcomes included magnetic resonance measures of meniscal integrity including meniscal size, shape, healing, extrusion and signal intensity. RESULTS: Thirty-eight studies with 1056 allografts were included. The weighted mean joint space loss was 0.032 mm at 4.5 years across 11 studies. Other radiological classification systems were reported in small numbers and with variable progression rates. Meniscal extrusion was present in nearly all cases, but was not associated with clinical or other radiological outcomes. Meniscal healing rates were high, although the size, shape and signal intensity were commonly altered from that of the native meniscus. The quality of the included studies was low, with a high risk of bias. CONCLUSION: There is some evidence to support the hypothesis that meniscal allograft transplantation reduces the progression of osteoarthritis, although it is unlikely to be as effective as the native meniscus. If this is proven, there may be a role for prophylactic meniscal allograft transplantation in selected patients. Well-designed randomised controlled trials are needed to further test this hypothesis. LEVEL OF EVIDENCE: Systematic review of studies, Level IV.