Traumatic Anterior Hip Dislocation in an Adolescent with an Associated Femoral Head “Hill-Sachs” Type Lesion

Abstract

Traumatic hip dislocations are uncommon injuries in the paediatric population, requiring urgent reduction to reduce the risk of avascular necrosis. Amongst other associated injuries, fractures of the femoral head, neck or acetabulum can occur. We present the case of a 14 year old boy who sustained a traumatic anterior obturator type hip dislocation with an associated supero-lateral “Hill-Sachs” type indentation osteochondral fracture of the femoral head. He was managed conservatively and by six weeks, was mobilising fully weight bearing unaided. At 17 month follow-up, he remained fully mobile with no complaints. Radiologically, the defect in the femoral head persisted with no evidence of collapse from avascular necrosis. This type of osteochondral fracture associated with hip dislocation has been reported in the adult population, with varying reports of an increased risk of post-traumatic arthritis. The presented case highlights the important role of computed tomography (CT) in assessing these injuries. Furthermore, it brings to light a rare type of injury of the paediatric femoral head that warrants further long-term follow-up studies to determine the associated risk of avascular necrosis, hip instability and post-traumatic arthritis.