Purpose: The aims of this study were to investigate whether osteonecrosis affects 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 in 44 patients in whom MRI and surgery were performed for painful internal derangements. At the time of surgery, a core biopsy specimen was obtained from 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 (18%). Bone marrow edema, which may be a precursor of osteonecrosis, was found in nine other joints. The MRI 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 diagnoses.
Conclusion: Osteonecrosis can affect the mandibular condyle, and this condition can be diagnosed with MRI. A combination of edema arid sclerosis of the bone marrow was the most reliable MRI sign of osteonecrosis. The cause, its clinical significance, and the need for treatment are unknown.
