[Avulsion fracture of the ischial tuberosity. A rare lesion whose early diagnosis and correct treatment may prevent late sequelae].

Avulsion fractures of the ischial tuberosity are often mistaken for sprains or a muscle tears. We present two cases of displaced fractures with a diagnostic delay of eighteen months and two years, respectively. Both cases were treated conservatively and resulted in discomfort on sitting and in one case persistent functional disability. Since early diagnosis is important for a successful treatment, an anteroposterior radiograph of the pelvis is recommended in patients presenting a history and symptoms indicating a lesion in the posterior aspect of the upper thigh. Accumulated experience indicates, that acute displaced fractures should be treated by open reduction and internal fixation.