Patients with osteoarthritis and avascular necrosis have better functional outcomes and those with avascular necrosis worse pain outcomes compared to rheumatoid arthritis after primary hip arthroplasty: a cohort study.
BACKGROUND
This study was conducted to assess whether patient-reported outcomes (PROs) differ by the underlying diagnosis (rheumatoid arthritis (RA)/inflammatory arthritis, osteoarthritis (OA), avascular necrosis of bone (AVN), other) in patients undergoing primary total hip arthroplasty (THA).


METHODS
We used prospectively collected data to assess the association of diagnosis with index hip function and pain. Moderate-severe activity limitation and moderate-severe pain were assessed at two- and five-year follow-up after primary THA using multivariable-adjusted logistic regression analyses. Odds ratios (OR) and 95% confidence intervals (CI) were calculated.


RESULTS
There were 5,707 primary THAs at two-years and 3,289 at five-years, 51% were women and the mean age was 65 years. The underlying diagnosis was RA in 3%, OA in 87%, AVN in 7% and other in 3%. In multivariable-adjusted analyses, compared to RA, diagnoses of OA and AVN were significantly associated with lower odds of moderate-severe activities of daily living limitations with an OR (95% CI) of 0.5 (0.3 to 0.8) (P = 0.01) and 0.4 (0.2 to 0.8) (P = 0.01), respectively, at two-years, but not at five-years, 0.7 (0.4 to 1.4) (P = 0.36) and 0.9 (0.4 to 1.8) (P = 0.78), respectively. At two-years, neither OA nor AVN were significantly associated with higher odds of moderate-severe pain (1.6 (0.6 to 4.5) (P = 0.40) and 2.8 (0.9 to 8.5) (P =0 0.06)), respectively. At five-years, AVN was associated with higher odds of moderate-severe pain with OR 4.1 (1.2 to 14.1) (P = 0.02), but not OA, 2.1 (0.7 to 6.5) (P = 0.22).


CONCLUSIONS
We found that patients with OA and AVN had better functional outcomes and those with AVN worse pain outcomes after primary THA, compared to patients with RA/inflammatory arthritis. Insights into mediators of these relationships are needed to better understand these associations.
Medicine Service and the Center for Surgical Medical Acute Care Research and Transitions (C-SMART), Birmingham VA Medical Center, Birmingham, AL, USA. Jasvinder.md@gmail.com.
Jasvinder A
JA
Singh
David G
DG
Lewallen
D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001172:Arthritis, Rheumatoid / Q000503:physiopathology / Q000601:surgery*; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000503:physiopathology / Q000601:surgery*; D010020:Osteonecrosis / Q000503:physiopathology / Q000601:surgery*; D010146:Pain / Q000209:etiology*; D011446:Prospective Studies; D011788:Quality of Life; D011795:Surveys and Questionnaires; D016896:Treatment Outcome