Clinical and Histopathologic Characteristics and Outcomes of Patients With Psoriatic Arthritis Undergoing Arthroplasty

Objective Patients with psoriatic arthritis (PsA) experience higher postoperative complication rates after total hip or total knee arthroplasty (THA and TKA, respectively) than patients with osteoarthritis, but contributing factors to this risk are poorly defined. We examined clinical factors predicting postoperative complications to determine whether PsA-specific disease activity is associated with adverse events (AEs).

Methods We conducted a prospective study of adults with PsA undergoing THA or TKA. Baseline assessments included demographics, BMI, Charlson Comorbidity Index (CCI), PsA disease activity measures, patient global assessment, medications, and patient-reported outcomes. Operative synovial tissue was assessed for inflammation. Postoperative AEs collected within 1 year were graded for severity (1-4) using the Clavien-Dindo (CD) classification. Logistic regression, adjusting for age and sex, assessed predictors of AEs and AE severity.

Results In total, 57 patients were included (24 THA, 33 TKA). At surgery, patients had moderate PsA activity (mean Disease Activity Index for Psoriatic Arthritis [DAPSA] score of 15.8) with minimal skin disease or enthesitis. CD grade 3-4 AEs occurred in 10 patients (18%). BMI and CCI were higher in THA patients with any AEs and all patients with grade 3-4 AEs. In the adjusted analysis, higher CCI was associated with grade 2-4 and 3-4 AEs, and BMI with grade 3-4 AEs. No PsA-specific measures, including DAPSA or synovial histologic inflammation, were associated with AEs.

Conclusion In patients with PsA undergoing THA/TKA, AEs were driven by comorbidity burden and obesity rather than PsA-specific disease activity or joint inflammation. This finding highlights the importance of perioperative optimization of comorbidities and weight.