Background Immunosuppressive medications are often stopped prior to arthroplasty to mitigate infection risk, but this may increase the risk of disease flares post surgery in patients with rheumatoid arthritis (RA).
Objectives To describe rates, characteristics, and risk factors for flare after total hip (THA) and total knee (TKA) arthroplasty surgery.
Methods Pre- and post-operative characteristics were examined in 58 RA patients undergoing TKA/THA. Perioperative medication use was standard of care: biologics were stopped before surgery, while steroids and methotrexate (MTX) continued. Clinicians evaluated RA clinical characteristics, on average, 0–2 weeks before and 6 weeks post-surgery. Post-surgery, patients completed weekly questions about RA symptoms, impact, and flare status using the OMERACT Flare Questionnaire. Baseline characteristics were compared using t-tests and chi-square, and multivariate logistic regression was used to identify baseline characteristics associated with post-surgical RA flares.
Results Of 68 patients, 10 (15%) were flaring prior to surgery and were excluded. 88% met 2010/1987 RA criteria; those who did not meet criteria were included by rheumatologist diagnosis. Patients had a mean [SD] age of 61 , BMI of 30.6 [7.2], and RA duration of 16  yrs. 59 (87%) were female, 53 (78%) were white, 33 (49%) were having THA, and 35 (52%) were on biologics. 35 (60%) had flared by 6 weeks post surgery. At baseline, flarers had significantly (p<.05) higher BMI, higher disease activity indicators (DAS28, RAPID3), inflammatory markers (ESR, CRP), and pain, and more were undergoing THA and used biologics (Table 1). After controlling for age, surgical joint, and baseline DAS28, the odds of flaring by 6 weeks post-surgery were significantly higher in patients who had discontinued biologics (OR 14.9, 95% CI 2.0, 112.0) or were obese (OR 6.0, 95% CI 1.1, 33.0).
Conclusions Flares are frequent in RA patients undergoing arthroplasty, particularly THA. Discontinuing biologics and obesity significantly increased the risk of flaring post-arthroplasty.
Acknowledgement This study was supported by the Clinical Translational Science Center (CTSC) (UL1-TR000457–06).
Disclosure of Interest None declared