Purpose

The aim of this study was to investigate the safety and clinical effectiveness of ACI in adolescent patients with a closed growth plate.

Methods and Materials

A total of 102 patients (60 adolescents (15 to <18 years) with a closed epiphysial growth plate in the affected joint and 42 young adults (18 to <35 years)) treated with ACI with spheroids for focal cartilage defects (ICRS grade 3 or 4) in the knee, were retrospectively included in a multicentre study.

Primary outcome was the Knee injury and osteoarthritis outcome score (KOOS) and secondary KOOS subscores. Other secondary outcomes were the International Knee Documentation Committee (IKDC) examination form, modified Lysholm, and magnetic resonance observation of cartilage repair tissue (MOCART). Outcomes were analyzed descriptively using 95% confidence intervals for the mean difference. Safety data consisted of treatment failure and adverse events related to the study treatment at 4 years follow-up.

Results

Adolescents had a defect size of 3.85 ± 2.18 cm² and a follow-up of 48.39 ± 19.45 months. Young adults had a defect size of 4.98 ± 1.27 cm² and a follow-up of 39.65 ± 15.23 months.

No significant differences between the adolescents and young adults were observed for the overall KOOS, most KOOS subscores (except for KOOS symptoms), IKDC, modified Lysholm and MOCART scores, with all patients achieving absolute good values (Table 1). Treatment failure rates were comparable with 3.3% for the adolescents and 4.8% for the young adults. In addition, the overall safety profile based on adverse events related to the study treatment of adolescent patients was comparable to young adult patients.

Conclusion

ACI using spheroids is a safe and effective treatment for large cartilage defects in the knee of adolescent patients with a closed growth plate. Furthermore, clinical and safety outcomes in adolescent patients are comparable to those of young adults.