Cell quality affects clinical outcome after MACI procedure for cartilage injury of the knee.

The aim of our study was to test the hypothesis that in early follow up after matrix guided autologous chondrocyte implantation (MACI), clinical results do not correlate with radiological and histological results, and that MACI as first line procedure and treatment of traumatic cartilage defects leads to better results compared to second line treatment and treatment of degenerative defects. Six and twelve months after MACI, patients IKDC-score was analysed, as well as the results of MRI-examinations. Specimens of the scaffold were histologically assessed at the time of implantation. The IKDC-score as well as the MRI-score improved significantly during follow up. The number of morphological abnormal cells was correlated with a poor clinical outcome. Defect aetiology proved to be a decisive factor for good clinical outcome. Patients with a short history of trauma (<1 year) and an osteochondritis dissecans were found to have better scores 1 year after MACI than patients with a trauma more than 1 year ago. Defect-size, patients age and -gender did not significantly influence the clinical outcome. No differences were seen when MACI was used as first- or second-line procedure. Defect aetiology and quality of the cells are decisive for the clinical outcome. MACI can produce good and very good clinical results even when used as second-line procedure.