BONE HARDNESS TESTING IN THE TRABECULAR BONE OF THE HUMAN PATELLA

Bone hardness of 10 human patellas in 15 regions and at three depths w as measured through in situ indentation tests. Indentation tests were performed perpendicular to the three articular surfaces (lateral and m edial facets, and central ridge area) and, thus, parallel to the trabe culae. Multiple regression analysis demonstrated a significant reducti on of bone hardness with depth. In addition, the lateral facet had a h igher bone hardness than the medial facet, and the proximal and centra l regions demonstrated higher bone hardness than the distal region. Ov erall, the proximolateral region of the patella exhibited the highest hardness compared with other regions. As bone hardness is indicative o f load bearing, these results may have important consequences for pate llar resurfacing and patellar component design.