No superior performance of hydroxyapatite-coated acetabular cups over porous-coated cups

Abstract

Background and purposeHydroxyapatite (HA) coating is believed to improve bone-implant ingrowth and long-term survival of prostheses. Recent studies, however, have challenged this view. Furthermore, HA particles may produce third-body wear and initiate aseptic loosening of implants. We report the performance of HA- and porous-coated acetabular cups in a prospective randomized trial.MethodsThis was an 8-year follow-up study of our previously published prospective randomized study to compare clinical outcomes, survival, periprosthetic bone mineral density, migration, and wear rates of HA- and porous-coated acetabular cups. Dual X-ray absorptiometry (DXA) and Ein Bild Roentgen Analyse (EBRA) measurements were used. 100 patients who underwent unilateral cementless total hip arthroplasty were randomized to either porous-coated cups or HA-coated cups. Patients were examined preoperatively and at 3, 6, and 9 months, and also 1, 3, and 8 years after surgery. 81 patients were available for 8-year follow-up, 40 with porous-coated cups and 41 with HA-coated cups.ResultsAge, sex, bone mineral density, and clinical results (Harris hip score) were similar in the 2 groups. The survival, wear, and migration patterns of the cups were also similar in both groups. The results of periprosthetic bone mineral density scans in region of interest 2 was in favor of the porous-coated cups, but there were no differences between the 2 groups in all the remaining regions of interest.InterpretationHA coating had no statistically significant effect on clinical results, survival, wear, or migration at the 8-year follow-up.

Higher early proximal migration of hemispherical cups with electrochemically applied hydroxyapatite (BoneMaster) on a porous surface compared with porous surface alone: a randomized RSA study with 53 patients

“…In accordance with studies on plasma-sprayed HA coatings we found little or no positive effect of electrochemically applied HA coating on migration of hemispherical cups after 2 years (Rohrl et al 2004, Valancius et al 2013. Our findings also indicate no improved long-term survival effect of electrochemically applied HA coating.…”

“…Plasma-sprayed HA coating results in better bony ingrowth and early implant fixation in experimental studies (Soballe et al 1992, Daugaard et al 2010). However, clinical results have not truly been able to show superior cementless cup fixation with HA over porous coating at midterm (Rohrl et al 2004, Valancius et al 2013 or long-term (Otten et al 2016, Lazarinis et al 2017.…”

Peri-acetabular bone remodelling after uncemented total hip arthroplasty with monoblock press-fit cups: an observational study

“…Although BMD did recover and stabilise in all zones, it remained significantly lower at follow-up than the baseline values [5]. Additionally, osteoconductive coating, such as hydroxyapatite [12] or alumina-reduced surface finish [13], did not improve peri-acetabular bone remodelling around modular cups. These data suggest that rigid acetabular fixation results in a loss of BMD in all zones over time and that this loss cannot be recovered by increasing the osteointegration properties of modular acetabular cups.…”

Peri-acetabular bone remodelling after uncemented total hip arthroplasty with monoblock press-fit cups: an observational study

“…Although BMD did recover and stabilise in all zones, it remained signi cantly lower at follow-up than the baseline values [5]. Additionally, osteoconductive coating, such as hydroxyapatite [13] or alumina-reduced surface nish [14], did not improve peri-acetabular bone remodelling around modular cups. These data suggest that rigid acetabular xation results in a loss of BMD in all zones over time and that this loss cannot be recovered by increasing the osteointegration properties of modular acetabular cups.…”