Hydroxyapatite-coated total primary hip replacement: 28-year follow-up survivorship.

Background: Survival at 25 years' follow-up for total hip arthroplasty (THA) has been reported at 5%-77%, with hydroxyapatite (HA) coating, due to its osteo-conductive properties, used to enhance implant fixation and survival. The progressive increase in life expectancy raises doubts regarding HA-coated THA survival and THA revision surgery risk. The aim of our study was to retrospectively analyse survival for primary uncemented fully HA-coated THA after 28 years' follow-up.

Methods: Our cohort survival study of the JRI Furlong HA-coated system retrospectively included patients aged 18-75 years who had undergone THA between 1992 and 1998 at our centre and who were followed up according to clinical records by orthopaedic surgeons to 2022. Data on THA revision surgery and its causes, follow-up, and death were analysed using Kaplan-Meier survival and Cox regression modelling.

Results: The cohort included 196 patients (268 hips) followed up to a maximum of 27.5 years (mean 15.54 (SD 6.01) years) with 62 patients (88 hips) >25 years. THA revision surgery was performed in 7.5% of cases, occurring a mean of 11.1 years following primary surgery. Aseptic loosening accounted for 4.4% of these revisions, affecting both the acetabular component (2.2%) and the femoral stem (1.3%). THA survival at 15 years', 20 years', and 27.5 years' follow-up was 95.5%, 88.3%, and 79.3%, respectively. According to the log-rank and Cox regression analysis, no significant relationships were found.

Conclusions: Furlong HA-coated stem provides excellent long-term bone fixation for a long-term follow-up over 27.5 years with an aseptic loosening stem revision rate of 1.3%.