Biomechanical Properties of Articular Cartilage in Different Regions and Sites of the Knee Joint: Acquisition of Osteochondral Allografts

Background: Osteochondral allograft (OCA) transplantation involves grafting of natural hyaline cartilage and supporting subchondral bone into the cartilage defect area of a joint to recover its biomechanical and tissue structure. However, differing biomechanical properties and donor-host matching may impair the integration of articular cartilage (AC). This study analyzed the biomechanical properties of the AC in different regions of different sites of the knee joint and provides a novel approach to OCA transplantation. Methods: ： Intact stifle joints from skeletally mature pigs were collected from a local abattoir less than 8 h after slaughter. OCAs were collected from different regions of the joints. The patella and thetibial plateau were divided into medial and lateral regions, while the trochlea and femoral condyle were divided into six regions. The OCAs were analyzed and compared for Young’s modulus, the compressive modulus, and cartilage thickness. Results: : Young’s modulus, cartilage thickness and compressive modulus of OCA were significantly different in different regions of the joints. A negative correlation was observed between Young's modulus and the proportion of the subchondral bone (r=−0.4241, P<0.0001). Cartilage thickness was positively correlated with Young’s modulus (r=0.4473, P<0.0001) and the compressive modulus (r=0.3678, P<0.0001). Conclusions: : During OCA transplantation, OCAs may be xenotransplanted into similar regions, or at the closest possible regions to ensure consistency of the biomechanical properties and cartilage thickness of the donor and recipient and, thus, easy integration with the surrounding tissue. A 7-mm depth achieved a higher Young's modulus, and may represent the ideal length.