Hydroxyapatite-coated titanium porous plasma spray tapered stem: experience at 15 to 18 years

Advocates of hydroxyapatite in primary total hip arthroplasty report enhanced fixation and early improvements in pain and function. Others report no difference in long-term outcomes with hydroxyapatite application to an already proven fixation surface. We previously reported more rapid clinical improvement with a proximally porous, plasma-sprayed titanium, tapered geometry stem. We now report the long-term followup data on 191 consecutive total hip arthroplasties in which a standard (130 hips) or the hydroxyapatite-coated stem (61 hips) was implanted. At average 12.7 years followup, one stem (noncoated) was revised for aseptic loosening. The Harris hip total and pain scores were similar. Survivorship of the femoral component with aseptic loosening as the endpoint was 99.2% for noncoated stems and 100% for hydroxyapatite stems. The long-term survivorship of plasma-sprayed titanium tapered stems was excellent regardless of hydroxyapatite application, with neither benefit nor detriment observed.