A STUDY OF MICROMOTION AND APPOSITIONAL BONE-GROWTH TO A CANINE MADREPORIC-SURFACED FEMORAL COMPONENT

A canine total hip arthroplasty model was used to examine micromotion and bone apposition to a proximally two-thirds madreporic-surfaced fem oral prosthesis. Micromotion was also measured following initial press -fit implantation into canine cadaveric femora. After initial press-fi t fixation and either 6 or 24 months of biologic fixation, micromotion was less than 23 mu m in the proximal and midstem regions, a magnitud e consistent with bone apposition. Bone apposition was greatest near t he junction of the madreporic and smooth surfaces and was not signific antly different between 6 and 24 months (51% at 6 months and 47% at 24 months). The quality of the interface tissue appears to be conducive to long-term fixation.