The recipient site is prepared by the coring of a bone plug which is slightly smaller than the donor plug. Finally the plugs are pressed into the recipient sites. These are some of the non-load bearing sites which have been recommended in the recent literature. The methods of thickness, curvature and contact analysis used for this study were all developed at our lab and have all been reported previously. Thickness is defined as the distance between the cartilage and bone surface along the normal to the cartilage surface.
Contact is defined as proximity between opposing surfaces.
Modeling To enable us to find the contact region on the femur through a wide range of flexion angles, we created 3D computer models of 5 cadaveric knees. Simulations were run for 10-110 degrees of flexion in increments of 10 degrees. For each position of the tibia, the model was used to solve for the position of the patella and to calculate the PFJ contact force. A 3D quasi-static mathematical multibody model for diarthrodial joints. Experimental work to verify these models was done using a joint rig on which the knee was mounted and loaded, coordinate measuring device to measure kinematics, and stereophotogrammetry to determine surface topography.