CCP-ACI on OCD up to 10mm

<b>Purpose: </b>To evaluate clinical, radiographic, and magnetic resonance (MR) results of costal chondrocyte-derived pellet-type scaffold-free autologous chondrocyte implantation (CCP-ACI) in osteochondral defects (ODs) up to 10-mm depth during 5 years of follow-up.<b>Methods: </b>Ten patients with CCP-ACI performed in ODs with depth up to 10 mm were retrospectively analyzed. The minimum follow-up period was 5 years. The median age was 36.5 (range, 20–55) years. The median size and depth of the OD lesion were 4.25 cm² (range, 2–6) and 7.0 mm (6–9), respectively. Clinically, the International Knee Documentation Committee, Lysholm, and visual analog scale pain scores were evaluated. Radiographically, the hip‒knee‒ankle (HKA) angle and the Kellgren‒Lawrence (K‒L) grade were assessed. On MR imaging, the magnetic resonance observation of cartilage repair tissue (MOCART) 2.0 score and defect depth were evaluated.<b>Results: </b>All average clinical scores improved significantly by 1, 2, and 5 years postoperatively. The average HKA angle and the proportion of K‒L grade did not change significantly within 5 years. The median total MOCART scores were 50 (range, 45–65), 50 (35–90), 57.5 (40–90), and 65 (50–85) at 6 months, 1 year, 2 years, and 5 years postoperatively, respectively (p = 0.001), with significant improvement at 2 years compared to that at 6 months postoperatively. The signal intensity of the repair tissue and subchondral change significantly improved from 10 (range, 10–10) to 12.5 (10–15) (p = 0.036), and from 10 (10–10) to 17.5 (0–20) (p = 0.017), respectively. Significant improvements were seen at 5 years postoperatively for the former and at 2 years postoperatively for the latter. The average depths on MR imaging were 6.7, 6.7, 6.8, 6.6, and 6.6 mm preoperatively and at 6 months, 1 year, 2 years, and 5 years postoperatively with no significant changes (n.s)<b>Conclusion: </b>CCP-ACI provided acceptable mid-term outcomes in ODs up to 10-mm in depth without bone grafting despite of no scaffold. The procedure can be one of minimally invasive treatment options for ODs without scaffold-related problems.