Preliminary Results of a Novel Single-Stage Cartilage Restoration Technique: Particulated Juvenile Articular Cartilage Allograft for Chondral Defects of the Patella

Purpose To evaluate outcomes and magnetic resonance imaging (MRI) findings after use of particulated juvenile cartilage for the treatment of focal Outerbridge grade 4 articular cartilage defects of the patella. Methods From 2007 to 2011, 16 patients (2 bilateral) underwent a novel single-stage articular cartilage restoration procedure using particulated juvenile articular cartilage allograft. We enrolled 15 knees (13 patients) in this study. The mean age at surgery was 26.4 ± 9.1 years, and the mean postoperative follow-up was 28.8 ± 10.2 months. A musculoskeletal radiologist evaluated each knee with postoperative MRI for the International Cartilage Repair Society cartilage repair assessment score, graft hypertrophy, bony changes around the graft, and percent fill of the defect. All patients also completed the Knee Injury and Osteoarthritis Outcome Score, International Knee Documentation Committee Subjective Knee Evaluation, and Kujala clinical outcome survey (scale, 0 to 100), as well as the Tegner activity scale and visual analog pain scale (scale, 0 to 10). Results The mean International Cartilage Repair Society cartilage repair assessment score on MRI was 8.0 ± 2.8, a nearly normal assessment. Of 15 knees, 11 (73%) were found to have normal or nearly normal cartilage repair. Three patients had mild graft hypertrophy whereas 2 had gross graft hypertrophy, 2 of whom required arthroscopic debridement because of symptoms. The mean fill of the defect at follow-up was 89% ± 19.6%, with 12 of 15 knees (80%) showing at least 90% defect coverage. The mean clinical outcome score at follow-up was 73.3 ± 17.6 for the International Knee Documentation Committee evaluation, and the mean scores for each subdomain of the Knee Injury and Osteoarthritis Outcome Score were as follows: 84.2 ± 14.2 for pain, 85.0 ± 12.3 for symptoms and stiffness, 88.9 ± 12.9 for activities of daily living, 62.0 ± 25.1 for sports and recreation, and 60.8 ± 28.6 for quality of life. The median score for the Kujala survey was 79 (range, 55 to 99). The median score on the Tegner activity scale was 5 (range, 3 to 9), and the mean score on the visual analog scale was 1.9 ± 1.4, indicating minimal pain. Conclusions Preliminary results suggest that cartilage restoration using particulated juvenile articular cartilage allograft offers a viable option for patients with focal grade 4 articular cartilage defects of the patella. Level of Evidence Level IV, therapeutic case series.