[Villonodular synovitis of the knee. Contributions of MRI].

This retrospective study included eight patients with villonodular synovitis of the knee (7 nodular forms and one villous form) who underwent magnetic resonance imaging and at least one arthroscopy. Joint enlargement and mild pain were the main manifestations. Other imaging studies provided little information. Magnetic resonance imaging showed highly suggestive hemosiderin-laden masses. Hemosiderin was most clearly seen on gradient echo sequences. Magnetic resonance imaging was also useful for determining the distribution of lesions. Intravenous gadolinium provided no additional information. Arthroscopy allowed to collect biopsy specimens and to perform synovectomy when called for. In our opinion, after a physical examination and plain roentgenograms, magnetic resonance imaging and arthroscopy should both be performed to determine the extent of lesions and to allow histological diagnosis and synovectomy, respectively.