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

Abstract

Abstract Background Bone stock preservation in total hip replacement is essential to allow for later revisions in an increasingly younger and fitter index patient population. While contemporary modular press-fit acetabular cups lead to rigid fixation with equatorial stress and central osteolysis, more elastic fixation may cause different peri-acetabular bone remodelling. The purpose of this study was to investigate changes in peri-acetabular bone mineral density (BMD) in uncemented elastic fixation with monoblock press-fit cups. Methods This prospective observational study included 45 patients with monoblock cups. We evaluated peri-acetabular BMD using dual-energy X-ray absorptiometry and reported functional outcomes and complications. Results At a mean follow-up of 24.2 ± 2.2 months, we found that BMD stabilised in DeLee and Charnley zones I and III and recovered to baseline value in zone II. The mean Harris Hip Scores improved significantly from 56.9 ± 20.0 to 97.2 ± 4.0 (p < 0001). Other than one peri-operative dislocation, we saw no post-operative complications. Conclusions We found favourable adaptive bone changes with BMD stabilisation in the equatorial zones and recovery to pre-operative values in the central zone. Additionally, excellent clinical outcomes and few prosthesis-related complications strengthened the favourable results of monoblock acetabular cups. Trial registration Registration number DRKS00017076.

Keywords

• Total hip arthroplasty
• Monoblock cups
• Bone remodelling
• Elastic fixation
• Bone mineral density
• DEXA