The humeral head as a potential donor source for osteochondral allograft transfer to the knee

This study aimed to determine whether osteochondral allograft plugs from the humeral head are a good topographic match to recipient sites on the femoral condyle. If so, the donor pool for allograft osteochondral transplantation to the knee may increase. Simulated osteochondral grafts of 1-cm, 1.5-cm, and 2-cm diameters were taken from the surface map of the humeral heads and superimposed and optimized on recipient sites of identical size on the femoral condyles. Primary measurement criteria included contour mismatch and circumferential step-off. These measurements increased with donor plug size. For the 1-cm and 1.5-cm plugs, the lowest mean mismatch (0.068 mm and 0.110 mm, respectively) and step-off (0.057 mm and 0.154 mm, respectively) occurred at the 30 degree medial position. For the 2-cm plugs, the lowest mean mismatch (0.183 mm) and step-off (0.227 mm) occurred at the 60 degree lateral position. Although 1-cm osteochondral plugs were a good topographic match to the recipient sites, the 2-cm plugs had a mismatch approaching 0.5 mm, an offset with a demonstrated peak contact pressure > 40% higher than normal. The topographic match of the humeral head suggests it is a potential donor source for osteochondral allograft transfer to the distal femur.