Pigmented villonodular synovitis after anterior cruciate ligament reconstruction using active bioprosthetic composite artificial ligament.

Pigmented villonodular synovitis (PVNS) is a proliferative disease that develops in the synovium of joints, especially the knee joints. A 52-year-old man visited our hospital with left knee pain, swelling and symptoms of collapse. Twenty-one years earlier, he had undergone anterior cruciate ligament (ACL) reconstruction using an active bioprosthetic composite (ABC) as an artificial ligament. T1 and T2 weighted magnetic resonance imaging of the knee joint showed rupture of the ABC ligament and low signal intensity of hyperplastic synovium. Arthroscopic total synovectomy without ACL reconstruction was performed and the lesion was histopathologically diagnosed as diffuse PVNS. Clinical outcomes included good pain relief and no recurrence of the disease after 5 years of follow-up.