Osteoarthritis and abnormal bone marrow of the mandibular condyle

Objective. The purpose of this study was to analyze the relationship betwee n abnormal bone marrow of the mandibular condyle and osteoarthritis. Study design. The relationship between abnormal bone marrow and osteoarthri tis of the mandibular condyle was analyzed in magnetic resonance images of the temporomandibular joints of 74 patients. Thirty-seven patients had magn etic resonance evidence of abnormal bone marrow, and 37 control patients ha d magnetic resonance images with normal bone marrow. Results. Fifteen of 37 patients with magnetic resonance evidence of abnorma l bone marrow had no magnetic resonance evidence of osteoarthritis; the oth er 22 patients had both abnormal bone marrow and osteoarthritis. Conclusions. Abnormal bone marrow of the mandibular condyle can occur separ ately from osteoarthritis; nearly one half of the joints with magnetic reso nance evidence of abnormal bone marrow did not have any evident osteoarthri tis. Abnormal bone marrow may therefore initially represent a separate dise ase entity Over time, secondary osteoarthritis probably develops in joints with initial bone marrow abnormalities.