EFFECT OF HYDROXYAPATITE AND TRICALCIUM-PHOSPHATE COATING ON FIBERMETAL POROUS COATED FEMORAL STEM – RESULTS AT 127 MONTHS

Abstract

For successful long-term result of non-cemented total hip arthroplasty (THA), direct biological bond between bone and implant through bony ingrowth into the implant is essential. To facilitate strong bond between bone and implant, hydroxyapatite (HA) or hydroxyapatite and tricalcium phosphate (HA-TCP) coated implants have been developed. Early clinical results of HA coated implants were reported very satisfactorily. However, the long-term effects of HA or HA-TCP coating on implants were still controversial. We evaluated the effect of hydroxyapatite and tricalcium phosphate (HA-TCP) coating on fibermetal coated femoral stem. 37 cases using fibermetal coated femoral stem with additional HA-TCP coating and 38 cases using fibermetal coated femoral stem without additional HA-TCP coating were included with average follow-up for 127 months. The mean Harris hip score at final follow-up 91.2 in HA-TCP group and 90.5 in porous group. Engh’s score at final follow-up was 19.1 in HA-TCP group and 18.7 in porous group. Six acetabular components (8.0%, 3 cases in each group) were revised for excessive PE liner wear and liner dissociation from locking mechanism. One femoral stem without HA-TCP coating was considered as a loosening and failure. None of the remaining femoral components (98.7%) showed any signs of aseptic loosening. No significant differences between two groups were found in all parameters. A cement-less porous coated femoral stem provided good clinical function and survival in the medium term regardless of additional HA-TCP coating.