Purpose
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 (OCDs) up to 10-mm depths during 5 years of follow-up.
Methods
Ten cases with CCP-ACI performed in OCDs with depths up to 10 mm were retrospectively analyzed. The minimum follow-up period was 5 years. All data were collected prospectively because the cases were involved in a clinical trial. The mean age was 36.5 years. The average size and depth of OCD lesion were 3.83 cm2 and 7.1 mm, 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 imaging, the magnetic resonance observation of cartilage repair tissue (MOCART) 2.0 score and defect depth were evaluated.
Results
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 (p = 0.758 and 0.200, respectively). The median total MOCART scores were 50, 50, 57.5, and 65 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 to 12.5 (p = 0.036), and from 10 to 17.5 (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 (p = 0.441)
Conclusion
CCP-ACI provided satisfactory mid-term outcomes in OCDs up to 10-mm depths without bone grafting despite of no scaffold or covering membranes.