Hip replacement surgery in patients with ankylosing spondylitis

Area of Science:

• Rheumatology
• Orthopedic Surgery
• Clinical Epidemiology

Background:

• Ankylosing spondylitis (AS) treatment has been revolutionized by tumor necrosis factor-alpha (TNF-α) inhibitors, yet their impact on spinal ankylosis and joint destruction remains unclear.
• The study investigates the effect of improved AS treatments on the utilization of hip arthroplasty surgery.

Purpose of the Study:

• To determine if advancements in AS treatment, specifically the introduction of TNF-α inhibitors, have influenced the rate of hip replacement surgeries.
• To compare hip arthroplasty trends in AS patients before and after the widespread adoption of TNF-α inhibitors.

Main Methods:

• Analysis of hip prosthesis procedures in AS patients (n=534) from the Norwegian Arthroplasty Register (1988-2010).
• Comparison of annual procedure trends between 1988-2002 and 2003-2010.
• Utilized osteoarthritis (OA) patients (n=95094) as a control group for comparison.

Main Results:

• Hip replacement surgery frequency increased in both AS and OA groups until 2002.
• From 2003-2010, a non-statistically significant trend (p=0.087) of reduced hip surgery frequency was observed in AS patients compared to OA.
• The mean age of AS patients undergoing hip surgery significantly increased from 49.9 to 56.4 years after 2002 (p<0.001).

Conclusions:

• The introduction of TNF-α inhibitors in Norway (2000-2003) correlates with a potential shift in AS prognosis.
• Findings suggest TNF-α inhibitors may slow or inhibit large joint arthritis progression in AS.
• This may lead to a reduced requirement for hip replacement surgery in ankylosing spondylitis patients.