Pigmented villonodular synovitis (PVNS) is a rare neoplastic proliferation of large joints, including the knee, with both localized PVNS (LPVNS) and diffuse PVNS (DPVNS) types. DPVNS is known to recur at a higher rate following resection
however, there is little evidence comparing patient-reported outcomes (PROs) between the two types. The purpose of this study was to compare PROs between patients with LPVNS and DPVNS involving the knee 2 years after surgical resection. We hypothesized that DPVNS would have worse 2-year PROs than LPVNS.Sixteen patients who underwent arthroscopic resection of pathology-confirmed PVNS involving the knee were enrolled in a prospective registry. Several PROs, including six Patient-Reported Outcomes Measurement Information System (PROMIS) domains and the International Knee Documentation Committee (IKDC) Subjective Knee Form, were assessed at baseline and at 2 years postoperatively. Mean scores between LPVNS and DPVNS groups were compared using a Wilcoxon exact test, while categorical variables were compared using a Fisher's exact test.Eleven patients (seven LPVNS and four DPVNS) completed both the baseline and 2-year PRO surveys. There were no significant differences in the demographic variables between groups, including age, body mass index, or prior surgical history (