Aim: To relate clinical progress following cartilage repair using TruFit plugs with appearance on MRI imaging with a view to determining safe healing in order for patients to return to activity, without needing invasive assessment.

Methods: 26 active sporting patients underwent cartilage repair using TruFit CB plugs (Smith & Nephew) for symptomatic chondral defects in the knee between February 2006 and September 2008. The plugs are a biphasic synthetic implant designed to reform both bone and articular cartilage. As part of this prospective series patients underwent MRI at post op time-points of 6, 12, 18 and 24 months. MRI was performed using a 1.5 Tesla scanner and later using a 3T scanner. We report the results of both including T2 cartilage mapping.

Results: All 26 patients were improved at latest follow-up when compared to pre-operative scores (mean follow up 15 months (range 6–30 months)). MRI evaluation demonstrates oedema like signal surrounding the plugs at an early stage but by 6 months the oedema resolves and the subchondral lamina is seen to reform. By 12 months the bone part of the plug has similar appearance to host bone and the neo-cartilage shows similar signal to native cartilage on all MRI modalities (1.5T, 3T and T2 mapping). This suggests that the repair tissue contains a high percentage of hyaline like cartilage. In one patient slow clinical improvement was reflected in the MRI appearance.

Conclusion: MRI imaging appears to relate to clinical improvement according to KOOS, IKDC, Lysholm, Tegner and SF36 scores. This indicates that MRI is a useful imaging tool for assessing healing, and knowledge of the recovery pattern is important for quantifying healing and for better advising patients on when it may be safe to load repaired areas.