Treatment of Full-Thickness Chondral Defects of the Knee With Autologous Chondrocyte Implantation

BACKGROUND: Autologous chondrocyte implantation (ACI) has been proven an effective method in treating large articular cartilage defects in short- or medium-term follow-up clinical studies. HYPOTHESIS: First generation ACI of patients with large full-thickness chondral defects of the knee could yield reliable functional outcomes after a minimum follow-up of 5 years. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Between 1997 and 2005, 42 patients (45 knees) underwent first generation ACI for symptomatic chondral defects of the knee. All patients had moderate to large (mean, 5.33 cm(2)) full-thickness chondral defects. Patients were evaluated using the International Cartilage Repair Society (ICRS) score, the International Knee Documentation Committee (IKDC) Knee Examination Form, the Tegner activity score, the Lysholm score, the Stanmore functional rating score, and a visual analog scale (VAS) for pain. RESULTS: The mean follow-up was 96 months (range, 62-144 months). At the final follow-up, a significant increase in all scores was recorded. Compared with preoperative findings, the median Lysholm score significantly improved, increasing from 56.0 to 89.0 (P < .05). The IKDC and the Tegner activity score showed significant improvement postoperatively, increasing from 45 and 5.5 to 69 and 6.5, respectively (P < .05). The mean ICRS improved from grade 3.8 preoperatively to grade 2.8 postoperatively (P < .05). The Stanmore functional rating score and the VAS pain score were decreased from 3.06 and 7.33 to 0.94 and 2, respectively (P < .05). Reoperation was required in 5 patients. In 2 of them graft failure was recorded due to degeneration or partial detachment, respectively. CONCLUSION: The long-term outcomes of our series support the effectiveness of first generation ACI in both pain relief and functional rehabilitation of patients with large full-thickness osteochondral defects of the knee.