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Functional Outcomes of Dual-Mobility versus Fixed-Bearing Primary Total Hip Arthroplasty in Ankylosing Spondylitis
Ahmad Abdallah Iessa Obeid1, Yan Zhang2, Xin-Hua Cai2
1Orthopedic Department, First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, 150000, People's Republic of China.
Purpose:
Hip involvement in ankylosing spondylitis (AS) can progress to bony or fibrous fusion, causing severe pain and disability. Total hip arthroplasty (THA) offers major benefits, but instability and implant choice remain key challenges. This study compared dual-mobility (DM) and fixed-bearing (FB) implants in AS patients with hip fusion.
Methods:
We conducted a retrospective cohort study of 51 patients with AS and hip fusion who underwent primary THA between 2019 and 2023. Patients received either DM or FB implants. Functional outcomes (The Short Form 12 Health Survey (SF-12), Harris Hip Score (HHS), Oxford Hip Score (OHS)), disease activity by Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), and radiographic parameters were assessed preoperatively and postoperatively.
Results:
Both DM and FB implants improved mobility, pain, and quality of life. DM implants provided significantly better functional outcomes at 3 and 6 months (all p < 0.01). BASDAI scores improved in both groups, with no long-term difference. Patients with bony fusion achieved greater functional gains, while those with fibrous fusion reported more symptom relief. No dislocations or major complications were observed within the follow-up period.
Conclusion:
THA proves to be an effective approach for managing hip fusion in patients with ankylosing spondylitis. While both implant types enhanced clinical outcomes, DM implants were associated with quicker recovery and better early functional results, suggesting an advantage for their use in this challenging patient population.
