[Pigmented villonodular synovitis of the knee. Treatment results in 22 cases]

The authors report their experience about 22 cases of pigmented villonodular synovitis of the knee observed between 1970 and 1997. The authors studied the results of treatments according to localization, evolutionary stage and condition of an early diagnosis.

Among thirty three cases of pigmented villonodular synovitis treated during the same period the knee was involved in twenty two cases. Diagnosis was done or highly suspected in 13 cases because of significant symptoms (iterative hemarthrosis, bony gap in both articular components of the joint) or by MRI. The biopsy performed in each case allowed histological assessment in 22 patients. Surgical treatment was achieved in 19 patients. Three knees were not operated (two patients refused; one had a synoviorthesis) the treatment was a synovectomy alone for fifteen patients; four patients, needed a knee prosthesis, because of important degenerative joint disease.

Fourteen patients, with a mean follow-up of five years were reviewed. Four had a recurrence which appeared between three and eight years after subtotal synovectomy for diffuse synovitis. There were no recurrence after arthroplastic treatment and in localized lesions.

Pigmented villonodular synovitis should be treated as soon as possible but its different clinical features make diagnosis sometimes difficult. Because of an aggressive tendency of the disease which finds expression in extensive lesions in joint and bone, and early diagnosis allowed by MRI could make the prognosis more favourable.

Surgical synovectomy is the usual treatment. In evolved stages arthroplasties are performed. Localized lesions and recurrences should need arthroscopic treatment.