Abstract
Fresh patellar allograft without violating the continuum of the articular cartilage was evaluated in rabbits. Twenty-four skeletally immature New Zealand White rabbits underwent resurfacing of the patella with fresh allografts and 92% (22/24) of the allografts survived. These specimens were analyzed to assess the geometric parameters of the patellofemoral joint anatomy as well as the biomechanical and histological properties of the patellar articular cartilage at 12 (n = 8), 26 (n = 7) and 52 weeks (n = 7) postoperatively. Despite incomplete restoration of the patellofemoral joint geometry, both the biomechanical and histologic results showed excellent preservation of the articular cartilage at 26 and 52 weeks. From the biomechanical testing, the aggregate modulus (Ha) and the permeability (k) of the transplanted cartilage for the 26- and 52-week groups showed no difference between the experimentals and the controls. For the 26-week group, the aggregate modulus was 0.70±0.07 MPa and 0.72±0.19 MPa for the experimental and control, respectively (p>0.5) and the permeability was (0.97±0.13)×10-15 m4/N-s and (1.17±0.33)×10-15 m4/N-s for the experimental and control, respectively (p>0.5). For the 52-week group, the aggregate modulus was 0.9310.14 MPa and 1.03±0.06 MPa for the experimental and control, respectively (p>0.5) and the permeability was 2.32±0.57)×10-15 m4/N-s and 2.12±0.85)×10-15 m4/N-s for the experimental and control, respectively (p>0.5). This study clearly demonstrates the long-term viability of articular cartilage in entire osteochondral patellar allograft in rabbits. © World Scientific Publishing Company.