Safe surgical hip dislocation for acetabular osteoid osteoma excision.

Excision of acetabular osteoid osteoma is technically difficult. We report osteoid osteoma of the quadrilateral plate in a 9-year-old girl who presented to us with persistent nocturnal pain, limp and restricted hip joint movement. The child was investigated with CT scan, MRI and triple-phase bone scan. The 0.7 cm nidus was located in the central portion of the cancellous bone in the quadrilateral plate, 1.94 cm inferior to the triradiate cartilage. The child was operated on through the safe surgical dislocation of the left hip. The location of the lesion was gauged from the preoperative CT scan measurement data and intraoperative fluoroscopic aid. The nidus with a sclerotic rim was burred down completely. Postoperative X-ray and CT scan revealed complete excision of the tumour, and the patient was pain-free. At 18 months follow-up, the patient is completely asymptomatic and walking normally.