Pigmented villonodular synovitis following arthroscopic laser surgery of the knee

Prise en charge de la synovite villonodulaire hémopigmentée du genou et de ses récidives

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.

Clustered localized pigmented villonodular synovitis

The localized form of pigmented villonodular synovitis (PVNS) is a rare pathologic entity characterized by limited involvement of the synovium. In the knee joint, which is the most commonly affected joint, the disorder generally presents as a single nodular lesion, or rarely as 2 or 3 multiple nodular lesions into the joint. We report 2 cases of localized PVNS in which multiple nodules were clustered in a limited patella fat pad area. Clustered, multiple nodular lesions in a limited area suggested to us to consider a variant of localized forms.

Subcutaneous pigmented villonodular synovitis caused by portal contamination during knee arthroscopy and open synovectomy

The etiology of pigmented villonodular synovitis (PVNS) is not clear. Researchers have suggested that localized nodular synovitis is an inflammatory process, but more recent studies tend to describe the lesion as benign synovial neoplasm with the potential of local recurrence. Although the theoretical risk of secondarily seeding the remainder of the knee is evident, this is the first report of a subcutaneous PVNS caused by portal contamination during knee arthroscopy and open synovectomy. It supports a neoplastic origin of this lesion.