The influence of hydroxyapatite coating on continuous migration of a Zweymuller-type hip stem: a double-blinded randomised RSA trial with 5-year follow-up

• Published in: Hip international Vol. 33; no. 1; p. 73
• Main Authors: Hoornenborg, Daniel, Schweden, Annelieke M C, Sierevelt, Inger N, van der Vis, Harm M, Kerkhoffs, Gmmj, Haverkamp, Daniel
• Format: Journal Article
• Language: English
• Published: United States 01.01.2023
• Subjects: Arthroplasty, Replacement, Hip - adverse effects; Arthroplasty, Replacement, Hip - methods; Coated Materials, Biocompatible; Durapatite; Follow-Up Studies; Hip Prosthesis; Humans; Prospective Studies; Prosthesis Design; Prosthesis Failure; migration; RSA; hydroxyapatite; Coating; osseointegration; hip
• ISSN: 1724-6067
• DOI: 10.1177/11207000211006782

Adding hydroxyapatite to a stem to enhance ingrowth is a matter of debate, even less is known about the long-term effect on stability by adding hydroxyapatite (HA). Continuous migration in the first 2-5 years is an indicator of failed osteointegration or pending failure, enhancing the risk of loosening within 10 years after initial surgery. We performed a double-blinded randomised RSA trial with 5-year follow-up, to compare and analyse migration characteristics of the hydroxyapatite uncoated (HA-) and hydroxyapatite coated (HA+) Zweymuller-type hip stem. In this single-centre prospective randomised controlled trial 51 patients were randomised to receive either a HA- or a HA+ Zweymuller-type hip stem during total hip replacement. After 5 years, 35 patients were still eligible for follow-up evaluation. The migration pattern was measured by use of radio stereometric analysis (RSA) images up to 2 years to evaluate short-term migration, additionally RSA images were obtained 5 years postoperatively to assess late-term and continuous migration. Furthermore, the improvement of clinical outcome was analysed by HSS and HOOS ADL and pain subscales preoperative and after 5 years. After initial settling of the implant, no significant migration occurred up to 5 years post-surgery for HA+ as well as HA- prostheses. Continuous migration within the 2-5 years' time interval was not observed for both HA+ nor the HA- group in all directions (  0.05). No significant difference between both groups was observed (  0.10). In both groups the HHS and HOOS improved significantly at 5 years compared to baseline for both groups. Improvement was not altered by the hydroxyapatite coating. No significant difference between both groups was observed (  0.58). Addition of a hydroxyapatite coating did not influence the migration 5 years postoperatively for the Zweymuller-type hip stem.Clinical Trial Protocol number: NL 23524.048.08.