Psoriatic Arthritis Does Not Increase Risk of Poor Outcomes Following Hip Replacement

A study of patients undergoing total hip arthroplasty found that patients with psoriatic arthritis face no greater risk of poor outcomes than patients who get hip replacements because of osteoarthritis.

Researchers compared results for 63 psoriatic arthritis patients with 153 who had cutaneous psoriasis and osteoarthritis and a large cohort of patients who suffered from osteoarthritis alone. The patients with psoriatic arthritis suffered significantly more co-morbidities than patients with osteoarthritis alone. They were also more likely to be obese, more likely to be current or former smokers and slightly more likely to be male. The groups were similar in terms of race, education level and other factors.

Patients from all 3 groups scored about the same before their procedures on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) of pain and function, and they posted similar WOMAC scores when they were measured again after their procedures. However, patients with psoriatic arthritis and psoriasis/osteoarthritis scored worse than those with osteoarthritis alone on the short form 36 mental component summary (SF-36 MCS), which was given before and after surgery, and on the EQ-5D questionnaire, which was given after surgery.

After regression analysis that controlled for potential confounders, these apparent discrepancies disappeared and patients from all 3 groups enjoyed similar outcomes after their hip replacements. Members of all 3 groups also expressed similar levels of satisfaction with the results of their operations.

“Neither psoriatic arthritis nor cutaneous psoriasis in conjunction with osteoarthritis are risk factors for poor outcomes after total hip arthroplasty,” the study authors wrote in Arthritis & Rheumatology. “This is important information to convey to psoriatic arthritis and psoriasis patients contemplating total hip arthroplasty.”

Prior research has found that psoriatic arthritis can lead to hip joint disease in a minority of patients. A Mayo Clinic study that was published in Annals of the Rheumatic Diseases tracked 504 psoriatic arthritis patients for a mean period of 5.7 years and found that 32 of them (6.3%) developed psoriatic hip arthropathy. Still, given that a couple million Americans have the disease, it creates a significant amount of hip dysfunction. More importantly, psoriatic hip arthropathy may predict which patients will suffer particularly severe cases of psoriatic arthritis.

“The patients affected had substantial orthopedic morbidity, which included total hip arthroplasty at a young age. In the patients available for long term follow up, the clinical illness progressed rapidly, with half of the affected patients requiring arthroplasty within 5 years after the onset of hip symptoms. In addition, patients with severe hip joint disease are more likely to require total knee arthroplasty than those without hip arthropathy,” wrote the authors of the Mayo Clinic study, who also noted that early detection of hip problems might obviate the need for hip replacement.

“The results of our study suggest that a potentially small period of time exists for medical therapeutic intervention in patients who have symptoms of hip joint disease…The strong association of symptomatic hip disease with psoriatic spondylitis suggests that alternative treatments such as anti-tumor necrosis factor should be considered early in the development of hip synovitis.”