Surgical management of villonodular-pigmented synovitis of knee: decisional algorithm

Pigmented villonodular synovitis (PVNS) of knee is an uncommon disease defined as benign despite presenting local aggressiveness and high propensity to recurrence. Etiology is still not completely understood. It seems to be a chronic inflammation process involving synovial membranes characterized by hemosiderin deposition which leads to pain, limitation of range of motion and, if not treated, bone erosion and osteoarthritis of knee. The gold standard for treatment is surgical excision; other adjuvant or alternative therapies are described, too. We present a case series of PVNS of the knee treated with surgical excision at our institution. Functionality was assessed using the Muscoloskeletal Tumor Society (MSTS) Score for lower limbs and Oxford Knee Score (OKS). Statistical analysis were performed. At the latest follow-up, our patients' mean MSTS score was 26.4 (30-18): 27.4 for those treated with posterior approach and 26.1 for the anterior ones. Only 5% of patients suffered local complications and 15% had a local recurrence of the disease. Adequate pre-operative study and careful surgical excision, that should be tailored to each patient are the key to obtain a low recurrence rate.