An assessment of the biological fixation of a retrieved Mayo femoral component.

Implant analysis was conducted on a retrieved Mayo femoral prosthesis that has a non-anatomic design with two distinct surfaces intended for osseous fixation. The prosthesis itself has a circumferential grit-blasted region interposed with the porous surfaces and involving the entire proximal stem. In addition, there are pads of mesh porous coating on the anterior, posterior, and medial surfaces proximally. A single, radiographically stable stem retrieved after 18 months secondary to recurrent dislocations was examined for osseous fixation by measurement of trabecular bone into the porous-coated and onto the grit-blasted surfaces of the stem. Results showed 17% +/- 7% bone ingrowth into the porous coated areas and 20% +/- 16% osseointegration onto the grit-blasted surfaces. These results are similar to percentages of ingrowth seen with more conventional, anatomic design prostheses.