Objective: To measure changes in joint contact mechanics, during simulated gait, in the presence of a medial femoral osteochondral defect and after filling the defect using two different polyvinyl alcohol implant configurations. Methods: Seven human cadaveric knees were tested under simulated gait, while the contact stresses on the tibial plateau were recorded using an electronic sensor. Each knee was tested using the following conditions: intact, defect, and after the defect has been filled with either 10% PVA, 20% PVA, 10% PVA + a porous titanium base, or 20% PVA + porous titanium base. Changes in contact area, total force, weight center of contact, and stress pattern differences were measured for each knee. Results: At 14% of the gait cycle, there were no changes in contact area observed between conditions. At 45% of the gait cycle, differences were seen in the meniscal-cartilage contact area with increases in contact area between the intact and 10% PVA as well as 20% PVA scaffolds. At 14% of gait, there was a significant increase in total force between intact and defect conditions and between defect and 20% PVA + pTi in the menical-cartilage region with forces of 179 ± 113 N, 278 ± 113 N, and 193 ± 96 N for the intact, defect, and 20% PVA + pTi respectively. At 45% of gait, there was a significant difference in total force between intact condition and the defect condition in the meniscal-cartilage contact area with average total force of 90 ± 73 N and 148 ± 75 N respectively. Differences were found in the cartilage-cartilage total force at 45% of gait between intact and all other conditions and between defect and 20% PVA + pTi. The total forces were 486 ± 134 N for the intact, 360 ± 158 N for the defect, and 431 ± 177 for the 20% PVA + pTi, and the remaining implants tested having total force values below 412 N. Conclusions: The presence of an osteochondral defect causes an increase in loading on the meniscus. Implants in the range of tissue engineered constructs can partially restore joint loading but cause alterations in contact stress patterns
