The etiology of TBMOS is not known yet.Possibly, TBMES and osteonecrosis may not be completely separate and distinct conditions. We performed a prospective study in 32 patients, among 1150 with knee pain that were examined, who fullfilled the following criteria: no history of trauma, inconclusive radiographs and MR images demonstrating a bone marrow edema pattern.The mean age of the patients was 45 years (35 to 56).Patients were followed up for three years clinical examination, laboratory examination, xrays, MRI and in most cases T99 scanning and CT scanning. The disease proved to be transient in 8 patients.In three of them edema extended to subchondral bone as in osteonecrosis with an illdefined bandlike signal.The mean width of the signal was 3 mm.In two other cases the type of manifestation has never been reported. We concluded that TBMES can extend to subchondral bone, as osteonecrosis does, through illdefined low signal band like lesions parallel to the articular surface and then resolve completely.It may also have various types of manifestation.We believe that TBME is a common status of different conditions including early avascular necrosis that the bone repair process managed to overcome.
