Pigmented Villonodular Synovitis of the Hip in Patients Undergoing Total Hip Arthroplasty: A Retrospective Case-Controlled Analysis

Pigmented villonodular synovitis (PVNS) is a condition affecting larger joints such as the hip and knee. Little is known regarding the impact of PVNS on total hip arthroplasty (THA). Therefore, the aim of this study is to determine if patients with PVNS of the hip undergoing primary THA experience greater (1) in-hospital lengths of stay (LOS); (2) complications; (3) readmission rates; and (4) costs.

Patients undergoing primary THA for PVNS of the hip from the years 2005 to 2014 were identified using a nationwide claims registry. PVNS patients were matched to a control cohort in a 1:5 ratio by age, gender, and various comorbidities. The query yielded 7440 patients with (n = 1240) and without (n = 6200) PVNS of the hip undergoing primary THA. Endpoints analyzed included LOS, complications, readmission rates, and costs. Multivariate logistic regression was used to determine odds ratios (OR) of developing complications. Welch’s t-tests were used to test for significance in LOS and cost between the cohorts. A P-value less than .001 was considered statistically significant.

PVNS patients had approximately 8% longer in-hospital LOS (3.8 vs 3.5 days, P = .0006). PVNS patients had greater odds of (OR 1.60, P < .0001) medical and (OR 1.81, P < .0001) implant-related complications. Furthermore, PVNS patients were found to have higher odds (OR 1.84, P < .0001) of 90-day readmissions. PVNS patients also incurred higher day of surgery ($13,119 vs $11,983, P < .0001) and 90-day costs ($17,169 vs $15,097, P < .0001).

Without controlling for global trends in LOS, complications, readmissions, or costs between 2005 and 2014, the findings of the study suggest that PVNS of the hip is associated with worse outcomes and higher costs following primary THA. The study is useful as orthopedic surgeons can use the study to educate patients of the complications which may occur following their hip surgery.