Background Historically, total hip arthroplasty (THR) outcomes have been poorer for patients with rheumatoid arthritis (RA) compared with osteoarthritis (OA). Whether this is true in a contemporary cohort of RA THR is unknown.
Objectives To compare outcomes of primary and revision THR in RA vs. OA.
Methods All THR and revision THR (RTHR) enrolled in a single institution arthroplasty registry between 5/1/2007 and 7/1/2010 with pre-operative data and who were alive at two years were eligible for this analysis. Patients with two eligible procedures only contributed data from the second. RA cases were identified by self report or ICD-9 code 714.0 and were validated by chart review. Patients with any other systemic rheumatic disease or fractures were excluded. Baseline and 2 year data were compared between RA and OA cases. Satisfaction at 2 years was measured on a Likert scale. Differences between groups were compared using unpaired Student’s t test, Chi-Square or Fisher’s exact test as appropriate.
Results From 6,515 cases, we identified 6012 eligible primary THR (202 RA) and 503 RTHR (58 RA). 95% had 2 year follow-up. (Table 1) RA were more likely to be female and had significantly more comorbidities. Compared with OA, RA THR had no significant difference in age or BMI, while RA RTHR were younger with lower BMI. RA THR had significantly worse baseline and 2 year WOMAC pain and function, though only 2-year function showed a clinically meaningful difference, (WOMAC difference >10). In addition, RA THR had 4x increased prevalence of poor pain and poor function at 2 years compared with OA. RA RTHR had significantly worse function and 2x increased prevalence of poor function at 2 years. RA THR were as satisfied as OA with pain relief but significantly less likely satisfied overall. RTHR showed no difference in satisfaction.
Conclusions Contemporary RA THR patients have similar absolute improvements in pain and function compared with OA but significantly worse 2-year pain and function. This is important information to convey to RA patients to ensure appropriate expectations. Further study of timing of THR in RA patients may help optimize outcomes.
Disclosure of Interest None Declared
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