Clinical results and mri findings after Collagen Meniscus Implant (CMI).

We report clinical results and MRI findings observed in 50 patients, who underwent collagen meniscus implant (CMI) between March 2001 and October 2003. Fifty patients, affected by irreparable meniscal lesions or had previously undergone partial medial meniscectomy, were arthroscopically treated with CMI, a tissue engineering technique designed to promote meniscal regeneration. Average age at the time of surgery was 38.4 years. The average size of the lesion/defect was 4.3 cm. Additional procedures included 16 ACL reconstruction, 8 high tibial osteotomy and 2 autologous chondrocyte implantation. All knees were evaluated according to the Lysholm II and Tegner activity scales. MRI was performed 6, 12 and 24 months postoperatively. Six arthroscopic examinations of the implant were performed at different times (6 to 16 months postoperatively). Postoperative complications included saphenus neuroapraxia in 3 patients and CMI rupture in 1 patient who presented persistent knee swelling. Follow-up averaged 16.5 months, with a minimum of 6 months. At most recent evaluation, 46 patients showed improvement of the clinical scores. A progressive uniform signal was evident by MRI. At second arthroscopic look, free fragments of the implant were observed in case of CMI rupture. In another patient, partial resorption of CMI was observed at the posterior horn. The remaining four arthroscopic examinations demonstrated regeneration of meniscal-like tissue. Clinical results achieved with CMI are promising. MRI demonstrated to be an effective tool for monitoring the evolution of the implant and showed good correlation with clinical outcomes and arthroscopic findings at follow up