Patient-Reported Outcomes after Surgery for Pigmented Villonodular Synovitis in the Knee: A Cohort Study

Area of Science:

• Orthopedics
• Oncology
• Rheumatology

Background:

• Pigmented villonodular synovitis (PVNS) is a rare neoplastic proliferation affecting large joints, with localized (LPVNS) and diffuse (DPVNS) subtypes.
• Diffuse PVNS (DPVNS) has a higher recurrence rate after resection, but patient-reported outcomes (PROs) comparison between LPVNS and DPVNS is limited.

Purpose of the Study:

• To compare PROs between patients with knee LPVNS and DPVNS two years after surgical resection.
• To test the hypothesis that DPVNS would be associated with worse 2-year PROs compared to LPVNS.

Main Methods:

• Prospective registry of 16 patients undergoing arthroscopic resection for knee PVNS.
• Assessment of PROs, including Patient-Reported Outcomes Measurement Information System (PROMIS) domains and International Knee Documentation Committee (IKDC) Subjective Knee Form, at baseline and 2 years postoperatively.
• Comparison of mean scores between LPVNS and DPVNS groups using Wilcoxon exact test and categorical variables using Fisher's exact test.

Main Results:

• Eleven patients (seven LPVNS, four DPVNS) completed the 2-year follow-up.
• No significant demographic differences were observed between the LPVNS and DPVNS groups.
• A trend towards higher mean PRO scores at 2 years was observed in the DPVNS group across all measures, despite lower baseline activity levels, though differences were not statistically significant.

Conclusions:

• Patients with knee DPVNS do not report worse patient-reported outcomes 2 years after arthroscopic resection compared to patients with LPVNS.
• While DPVNS showed a trend towards greater improvement in several PRO measures, these did not reach statistical significance.
• Two recurrences were noted in the DPVNS group, compared to none in the LPVNS group, highlighting potential differences in disease behavior despite similar PROs.