Clinical, histologic, and radiographic outcomes of distal femoral resurfacing with hypothermically stored osteoarticular allografts

BACKGROUND: Fresh osteoarticular allograft transplantation has a long history of clinical success. These grafts have typically been implanted less than 1 week from donor asystole. HYPOTHESIS: Osteoarticular allografts stored 4 to 6 weeks represent a viable alternative to treat full-thickness cartilage and osteochondral defects of the distal femur as measured by clinical, histologic, and magnetic resonance imaging (MRI) criteria. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Osteoarticular allografts were implanted after a mean graft storage time (at 4 degrees C) of 36 days (range, 28-43). Sixty-seven patients received massive hypothermically stored osteoarticular allografts. Ten knees in 8 of these patients underwent second-look arthroscopic evaluation and biopsy at a mean of 40 months (range, 23-60) after implantation. Clinical assessment was performed using multiple outcome measures and sequential MRI evaluations. Biopsy specimens were obtained from the graft as well as from native articular cartilage at the time of second-look arthroscopy for histologic analysis. RESULTS: The mean International Knee Documentation Committee scores were as follows: preoperative, 27 (range, 9-55); postoperative, 79 (range, 56-99); P = .002. The mean Lysholm scores were as follows: preoperative, 37 (range, 12-47); postoperative, 78 (range, 55-90); P = .002. The mean Short Form-36 physical scores were as follows: preoperative, 38 (range, 24-55); postoperative, 51 (range, 39-61); P = .002. The mean Tegner scores were as follows: preoperative, 4.3 (range, 1-9); postoperative, 5.3 (range, 4-7); P = .16. The mean International Cartilage Repair Society score at follow-up was 10 (nearly normal) (range, 7-11). The mean modified Outerbridge scores were as follows: preoperative, 4.3 (range, 3-5); postoperative, 0.6 (range, 0-1); P = .002. The mean graft and native cartilage cellular density and viability were not statistically different. CONCLUSIONS: Fresh-stored osteoarticular grafts for full-thickness articular surface defects of the distal femur appear to offer a viable biological method to restore knee function. Our study suggests that osteoarticular grafts stored in cell culture medium at 4 degrees C for 4 to 6 weeks provide successful short-term clinical outcomes.