초록/요약

Background: Mycobacterial osteomyelitis involving only the epiphysis of a long bone is extremely rare, and its clinical and radiographic features remain unclear. The purpose of this study was to characterize mycobacterial epiphyseal osteomyelitis and to identify differences between its features and those reported for epiphyseal osteomyelitis caused by bacteria or unidentified pathogens. Methods: We retrospectively reviewed the cases of eight children (five males and three females) who presented at a median age of nineteen months (range, twelve to twenty-five months). Clinical findings were compiled. Radiographs and magnetic resonance imaging (MRI) were used to determine local spread of the abscess outside the epiphysis during the disease course. At the time of the latest follow-up evaluation, the presence of limited joint mobility or growth disturbance was determined. Physeal damage was evaluated with use of MRI. Results: Pathogens were identified through multiplex polymerase chain reaction. Mycobacterium bovis bacille Calmette-Guérin (BCG, Tokyo-172 strain) was identified in four patients; Mycobacterium tuberculosis, in three patients; and nontuberculous mycobacterium, in one patient. The lesion was located at the distal femoral epiphysis in six patients, at the proximal tibial epiphysis in one patient, and at the proximal humeral epiphysis in one patient. The abscess was confined to the epiphysis at the time of initial presentation but, over time, extended outside the epiphysis in seven cases. The lesion was initially located in the cartilaginous epiphysis in two patients, which could be diagnosed only on MRI. Seven patients worsened despite surgical drainage and medication, and five required additional surgery. At follow-up at a mean of 4.1 years (range, 1.3 to 7.8 years), focal physeal damage was evident in five patients, and clinical growth disturbance was evident in one patient. Conclusions: In contrast to the reported benign features of epiphyseal osteomyelitis caused by bacteria or unidentified pathogens, mycobacterial epiphyseal osteomyelitis seems to have an unfavorable clinical course that tends to lead to physeal damage. MRI is useful for early diagnosis of a cartilaginous lesion and evaluation of abscess spread and physeal damage. Level of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.