Autologous matrix induced chondrogenesis (AMIC) is an innovative treatment for localized full-thickness cartilage defects. This study was performed to review and compare the outcome of AMIC in an open versus an arthroscopic technique.

Within the context of clinical follow-up, 50 patients were evaluated, 1 and 2 years after the index procedure. While surgery was performed in 30 cases in an open procedure (group 1), 20 patients (group 2) were treated with an arthroscopic technique.

No differences were seen comparing baseline data (e.g. age, defect size) of group 1 and 2. The majority of patients was satisfied with the postoperative outcome, reporting a significant decrease of pain (VAS group 1/group 2: preoperative 6.1/5.2, 1 year postoperative 2.4/2.5, 2 years postoperative 2.1/1.5). Significant improvement of the Lysholm score was observed as early as 12 months after AMIC and further increased values were notable up to 24 months postoperatively (group 1/group 2: preoperative 45.8/49.9, 1 year postoperative 79.0/79.5, 2 years postoperative 80.5/81.8). Analyzing the subgroups of the KOOS score of group 1 and 2 reveals comparable results with significant increases of the values. No significant differences were seen comparing group 1 and 2.

This is the first study comparing the outcome of AMIC in an open or arthroscopic technique. In the recent series, we did not see a significant difference comparing the open and arthroscopic technique at mid-term follow-up. In conclusion, both techniques should be considered as alternative treatment options.