Revision total hip arthroplasty in patients with ankylosing spondylitis: Mid-term results

Abstract

Background: Few studies have reported on the outcome of revision total hip arthroplasty (THA) for ankylosing spondylitis (AS). Therefore, we sought to investigate the clinical and radiographic outcomes of revision THA in patients with AS.

Hypothesis: The mid-term outcome of revision THA in AS patients was comparable to conventional revision THA.

Materials and methods: Forty-one patients with AS who underwent revision THA (on a total of 51 hips) between April 2004 and June 2018 were included. The mean follow-up duration was 7.5±3.6 years (3.0-15.8 years). Clinical outcomes were assessed using the Bath Ankylosing Spondylitis Functional Index (BASFI), Harris Hip Score (HHS), and the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index. Complications were assessed at each follow-up. Radiological outcomes were examined by reviewing postoperative plain radiographs.

Results: Significant improvements were seen in BASFI, HHS, and WOMAC scores (p<0.01). Postoperative combined range of motion (ROM) was 128.9±45.3° (range, 60-300°). Complications included heterotopic ossification, periprosthetic fractures, aseptic loosening, osteolysis, reinfection, residual pain or stiffness, delayed wound healing, numbness, deep vein thrombosis, leg length discrepancy, and posterior dislocation. Five (9.8%) of the 51 hips were treated with re-revision due to aseptic loosening, re-infection, or re-fracture. The incidence of dislocation was 1.9% at 7.5 years. Implant survival for all reasons was estimated to be 96.3% at 5 years, 85.9% at 10 years and 61.0% at 15 years. Forty-two (82.4%) hip revisions were rated "satisfactory" or "very satisfactory" by the patients.

Conclusions: The mid-term result of revision THA for patients with AS is comparable to conventional revisions in terms of implant survival, despite high complication rates. The benefit-risk ratio of these indications is acceptable but deserves specific information for these patients.

Level of evidence: IV; case series.

Keywords: Ankylosing spondylitis; Complication; Outcome; Revision THA.