Chondrocyte-seeded type I/III collagen membrane for autologous chondrocyte transplantation: prospective 2-year results in patients with cartilage defects of the knee joint.

PURPOSE: We report the 2-year clinical results and identify prognostic factors in patients treated with autologous chondrocyte transplantation by use of a collagen membrane to seed the chondrocytes (ACT-CS).
METHODS: This is a prospective study of 59 patients who were treated with ACT-CS and followed up for 24 months. Clinical function was assessed by International Knee Documentation Committee (IKDC-2000), objective International Cartilage Repair Society, and Lysholm scores before surgery and at 6, 12, and 24 months after surgery.
RESULTS: On the basis of objective International Cartilage Repair Society (ICRS) rating, the percentage of patients rated A (normal) and B (nearly normal) increased from 33.9% preoperatively to 92.5% at 24 months after ACT-CS. IKDC and Lysholm scores increased from 50.1 points (SD, 13.4) and 60.5 points (SD, 9.4), respectively, to 76.1 points (SD, 15.2) (P < .001) and 82.5 points (SD, 13.7) (P < .001), respectively, at 24 months. The failure rate was highest, at 26.7% at 2 years' follow-up, in the subgroup of patients who underwent ACT-CS as a salvage procedure. The rate of failures in patients with isolated cartilage defects was 5.9%.
CONCLUSIONS: ACT-CS represents a technical modification of membrane-associated autologous chondrocyte transplantation that combines easy handling and attractive application properties with reliable clinical results 24 months after surgery, especially in patients with isolated cartilage defects. Even though the failure rate was higher in patients with kissing lesions or mild osteoarthritis, ACT-CS also seems to improve function in a large proportion of such patients. LEVEL OF EVIDENCE: Level IV, prospective case series. 2010 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.