Neither psoriatic arthritis (PsA) nor cutaneous psoriasis (PsC) is an independent predictor of poor postoperative pain or function following a total hip arthroplasty, according to the results of a case-control study by Dr. Lisa A. Mandl and her colleagues.
The study’s participants underwent surgery between May 1, 2007, and Dec. 31, 2010, in a center that performs more than 4,300 THAs annually. All subjects lived for at least 2 years after their operations. The researchers compared pre- and postoperative data from patients in the following three categories: those with PsA, those with PsC without evidence of inflammatory arthritis, and those with osteoarthritis (OA). Patients with OA comprised the control group, which excluded any patient who self-reported a history of PsA, rheumatoid arthritis, lupus erythematosus, or any other systematic rheumatic disease, or who had documentation of skin psoriasis. The researchers acquired postoperative self-report data from 47 PsA patients, 106 PsC patients, and 864 OA patients. Seventeen percent of patients submitted information on their status at 1 year, 69% at 2 years, and 14% at 3-5 years.
The primary outcomes of interest were postoperative pain and function, which were assessed via the Hip Osteoarthritis Outcome Score (HOOS), from which the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was derived.
There were no statistically significant differences in postoperative WOMAC pain or function scores between the three groups of patients (P = .78 and .96, respectively). The mean pain scores were 14.9, 6.1, and 15.8 for patients with PsA, PsC, and OA, respectively. These patients’ mean function scores were 16.3, 19.6, and 18.8 for the PsA, PsC and OA groups, respectively.
Overall levels of satisfaction with the surgery were similar among the three groups (P = .54). Ninety-three percent of the PsA patients, 79% of the PsC patients, and 84% of the OA patients were “very satisfied” with their total hip arthroplasty. Between 1% and 3% of each group reported being “very dissatisfied” with their surgery. The researchers found that extent of skin disease was not associated with worse postoperative pain or function.
“Further work needs to be done to better understand the interplay of disease activity and quality of life on the outcomes of [total hip arthroplasty] in PsA and PsC,” they wrote.
Read the report in Arthritis & Rheumatology (doi: 10.1002/art.39431).