MR imaging of meniscal allografts: Correlation with clinical and arthroscopic outcomes

PURPOSE: To correlate magnetic resonance (MR) imaging findings after meniscal transplantation with those at clinical, arthroscopic, and histologic examination. MATERIALS AND METHODS: Twenty-four patients (29 menisci) underwent MR imaging after meniscal transplantation. Nineteen patients underwent arthroscopy, and the peripheral capsular attachment, degenerative areas, or both were sampled for biopsy. MR findings were correlated with those at clinical, arthroscopic, and histologic examination. RESULTS: MR imaging enabled accurate assessment of allograft attachments. Fragmentation and frank extrusion were associated with full-thickness chondral loss. Allograft degeneration, indicated by an increase in signal intensity, was seen with moderate and severe chondral wear. Clinical results were worse with meniscal extrusion, with complaints of locking. Patients with mild fragmentation reported pain without locking. Histologic examination of excised allografts revealed myxomatous degeneration without immunologic reaction. CONCLUSION: MR imaging can help assess allograft placement and articular cartilage and enable differentiation of fragmentation from extrusion. Preoperative assessment of articular cartilage is important to identify patients who may be at risk for failure.