[Acute hematogenous osteomyelitis of the obturator rim in seven children]

Acute osteomyelitis of the rim of the obturator foramen is rarely reported. The clinical presentation is atypical, making diagnosis a difficult task. We report a series of seven cases of osteomyelitis of the obturator rim which illustrate the different features of this localization.

The series included seven boys with osteomyelitis involving the obturator foramen. We reviewed the clinical history, the diagnostic approach and management. Complications and anatomic outcome were noted at mean three years follow-up (range one to 10 years).

Mean age was 9.5 years (five to 12 years). Bilateral involvement was noted in one boy. Mean time from symptom onset to consultation was five days and mean time from consultation to hospitalization was eight days. No specific clinical presentation could be identified. Fever was not a constant feature. Mean body temperature was 38.6 degrees C and was not greater than 38.5 degrees C in four children. Symptoms were limited to hip pain in five cases and abdominopelvic pain was noted in two. Physical examination failed to trigger exquisite ischial or pubic pain in two patients. The osteomyelitis involved the ischiopubic ramus in four cases, the ischium in two with one bilateral case, and the pubis in one. Certain diagnosis was established as follows: MRI findings plus isolation of the pathogenic agent (n=4) ; the plain x-ray showed a defect in the ischiopubic ramus, MRI showed signs favoring osteomyelitis of the ischiopubic ramus and surgery evacuated a purulent collection (n=1) ; strong uptake of the obturator rim on scintigraphy (n=2). Medical treatment was given in all cases and surgery was performed in six patients. Outcome was noted at three years follow-up, range one to 10 years. All patients recovered normal function. There were no complications.

Hematogenous osteomyelitis of the pelvis is exceptional (2-11 % of cases of osteomyelitis). Localization in the obturator rim is rare. We discuss the specific diagnostic and therapeutic features of this localization. Despite the controversy concerning the treatment of pelvic osteomyelitis and in particular cases involving the obturator rim, prognosis is generally good. No complications have been described in the literature specifically associated with osteomyelitis of the obturator rim.