An unstable fracture dislocation of the hip due to an occult free intra-articular fragment: case report.

A case report is presented of a 53 year old man who presented with posterior dislocation of the hip after a road traffic accident. Initial management by closed reduction failed due to presence of an occult free intra-articular fragment. This fragment was not visualised on plain A-P and lateral X-ray views. The cause of the failed closed reduction was eventually detected by CT scan. Open reduction and removal of the bone fragment was done and the hip remained stable thereafter. It is concluded that plain X-rays are not adequate in the diagnosis of free intra-articular bone fragments within the hip joint and CT scanning is advised for accurate detection of such occult bine fragments.