Osteonecrosis of the temporomandibular joint: Correlation of magnetic resonance imaging and histology

Purpose: The aims of this study were to investigate whether osteonecrosis a ffects the mandibular condyle and to determine whether this condition could be diagnosed with magnetic resonance imaging (MRI). Materials and Methods: The study was based on 50 temporomandibular joints i n 44 patients in whom MRI and surgery were performed for painful internal d erangements. At the time of surgery, a core biopsy specimen was obtained fr om the marrow of the mandibular condyles, and the histological observations were correlated to T1- (proton density) and T2-weighted MR images. Results: Histological evidence of osteonecrosis was found in nine joints (1 8%). Bone marrow edema, which may be a precursor of osteonecrosis, was foun d in nine other joints. The MRT was 78% sensitive and 84% specific for the diagnosis of osteonecrosis of the mandibular condyle. However, the positive predictive value was only 54% because of a number of false-positive MRI di agnoses. Conclusion: Osteonecrosis can affect the mandibular condyle, and this condi tion can be diagnosed with MRT. A combination of edema and sclerosis of the bone marrow was the most reliable MRI sign of osteonecrosis. The cause, it s clinical significance, and the need for treatment are unknown.