ANALYSIS OF THE BONE SURFACE-AREA IN RESECTED TIBIA - IMPLICATIONS INTIBIAL COMPONENT SUBSIDENCE AND FIXATION

Anterior subsidence of the tibial component is still a clinical compli cation requiring revision in total knee replacement. Using the scannin g electron microscope, a quantitative 3-dimensional stereoscopic and d igitizing study was conducted on the cortical and cancellous bone surf ace area from 10 resected human cadaveric tibia. The data demonstrated that the cortical bone surface area covered an average of 6% of the t otal tibial surface area, cancellous bone 18%, and bone marrow space 7 6%. By conducting anatomic regional analysis, the data showed signific antly higher (p less than or equal to 0.05) bone quantities in the pos teromedial and medial regions as compared with the anterior and antero lateral regions. These data help to explain why tibial component subsi dence occurs anteriorly in total knee replacement. The data also sugge st that if long-term component subsidence and loosening is to be limit ed, either biologic cement or bone cement would be required to increas e the surface attachment between the tibial component and resected can cellous bone.