[Surgical management of pigmented villonodular synovitis of the knee: Retrospective analysis of 28 cases].

PURPOSE OF THE STUDY: The objective of this retrospective study was to analyze clinical observations in pigmented villonodular synovitis (PVNS) of the knee as well as response to treatment in order to better define the diagnostic approach and surgical treatment and follow-up of this rare benign proliferative disease of the synovial observed primarily in the knee joint.

MATERIAL AND METHODS: Twenty-eight patients (13 men and 15 women) were treated for PVNS in our unit between 1996 and 2004. Twenty patients had diffuse disease and eight localized disease. In the localized forms, symptoms mimicked those provoked by intra-articular foreign bodies or meniscal tears (n = 6) and had been present for 14 months on average at first consultation. Mean age at treatment onset was 40 years (range 20-62). Arthroscopic or open surgery was used for resection. In the diffuse forms, symptoms had begun 15 months on average before first consultation and were mainly spontaneous hemarthrosis or diffuse non-specific knee pain. Mean age at treatment onset was 38 years (range 15-59). Bone lesions were observed in four patients. Synoviorthesis or surgical synovectomy were performed. Mean follow-up was 97 months (range 12-309). Outcome was compared between the different aspects of localized and diffuse PVNS and treatment modalities.

RESULTS: In the localized forms, there were no complications after surgical treatment and there were no cases of recurrence (one surgical revision at four months following incomplete resection). For the diffuse forms, the cumulative recurrence rate was 50%. Mean time to recurrence was 37 months. Three patients developed a stiff knee after open synovectomy. Surgical treatment was required in four patients seen late after development of bony lesions (total knee arthroplasty in three). Clinical outcome was good with a gain in knee flexion.

DISCUSSION: MRI is essential for the topographic diagnosis and to guide surgical treatment. In severe or advanced primary diffuse disease or in the event of local recurrence, adjuvant synoviorthesis can be proposed four to eight weeks after initial surgery. The risk of recurrence for diffuse forms warrants an annual MRI for the first four years.