Abstract
Summary Statement
For RA patients undergoing TKR, the gain in function at 6 months following surgery is less than that experienced by OA patients; for THR, however, gains are similar in OA and RA patients.
Introduction
Total joint replacement (TJR) is commonly used in rheumatoid arthritis (RA) patients and yet little information is available to quantify their functional gain following surgery and how it differs from what the osteoarthritis (OA) population experiences. Therefore, we examined 6-month functional outcomes of TJR in a population-based observational cohort of RA and OA patients who underwent total hip (THR) or knee (TKR) replacement.
Methods
Patients undergoing primary TKR from 7/1/11 through 12/3/12 were identified from the FORCE-TJR national research consortium which enrolls patients from 111 surgeons across 27 states in the US. The registry gathers data from patients, surgeons and hospitals on patient demographics, underlying type of arthritis, operative joint severity based on the estimated Western Ontario and McMaster Universities Arthritis Index (WOMAC) using the Hip and Knee Disability and Osteoarthritis Outcome Scores, function based on the Short Form 36 Physical Component Score (PCS), and mental health using the SF-36 Mental Component Score (MCS). Descriptive statistics were performed.
Results
There were 95 RA and 991 OA patients who underwent primary TKR, and 59 RA and 740 OA patients who underwent primary THR. Among TKR patients, RA patients are more likely to be women (68% vs. 61%), nonwhite (17% vs. 9%), unmarried (59% vs. 70%) with an annual income of ≤$45,000 (57% vs. 39%) as well as lower baseline emotional health (48 vs. 52) and functioning (31 vs 33). Among THR patients, RA patients are more likely to be nonwhite (18% vs. 8%), unmarried (66% vs. 69%) with an annual income of ≤$45,000 (54% vs. 34%) as well as lower baseline emotional health (46 vs. 51) and functioning (30 vs 32). RA patients undergoing TKR have less functional gain 6 months post-surgery (6.6 vs. 9.7; p=0.002) as compared to OA patients. In contrast, RA patients who undergo THR have similar functional gain (11.6 vs. 13.8; p=0.13) as compared to OA patients.
Discussion/Conclusion
RA patients have less functional improvement as compared to those with OA when undergoing TKR but similar gains when undergoing THR.
