Background

Viable Cartilage Allograft (VCA) contains cryopreserved viable allogeneic cartilage fibers mixed with chondrogenic matrix. In-vitro and animal studies and a prospective case series were completed with VCA to assess safety and benefits in treating focal knee cartilage defects. Our hypothesis is that VCA is a safe single stage procedure in isolated chondral defects with results comparable or better than other single stage procedures.

Methods

Cell viability and functionality of VCA was evaluated in-vitro. VCA was also evaluated in a goat cartilage repair model. 19 patients (7/12 M/F) were implanted, mean age 26.77 (15-56), mean BMI 27.59 ± 6.1, mean follow-up 19 months (range 12.0–26.3 months). Symptomatic International Cartilage Repair Society (ICRS) grade 3 / 4A lesions of the femoral condyle (n=4) or patella (n=14) were treated. Lesion sizes ranged from 1.4-6.0 cm2 (mean defect size was 5.025 cm2). International Knee Documentation Committee (IKDC), Knee injury and Osteoarthritis Outcome (KOOS) subscales, Lysholm, Short Form-12 (SF-12), visual analog scale (VAS) and pain frequency levels were assessed. Radiographs and magnetic resonance imaging (MRI) were performed at 3 and 6 months (M).

Results

In vitro assessment confirmed VCA contains viable and functional chondrocytes. The goat study confirmed VCA is effective for cartilage repair. Lysholm (25.3), KOOS: Pain (12.2), Symptoms (19.6), ADLs (14.5), Sports (13.7), and QOL (28.9) at 6 months increased from pre-operative baseline (POB) and were maintained at 12 months: IKDC (72.2), Lysholm (84.2), KOOS: Pain (87.8), Symptoms (80.7), ADL (97.6), Sports (72), and QOL (61.2). MRI imaging at 6 and 12 months showed viable preliminary cartilage tissue with no significant bone edema or graft delamination. Second look arthroscopy (2 patients) demonstrated complete fill and incorporation (Brittberg Scores 11/12). Functional scores improved at 24(M): IKDC (87.3), Lysholm (87.7), KOOS: Pain (92.5), Symptoms (86.2), ADLs (95.6), Sports (82.9), QOL (82.1).

Conclusion

VCA is an off-the-shelf, single stage, conformable allogeneic graft that treats chondral defects with no additional fixation. Pre-clinical and short-term prospective clinical studies show VCA can safely treat chondral defects with potential advantages to existing options.