Traumatic hip dislocation in the paediatric population: A case series from a specialist centre.

Introduction: Traumatic hip dislocation is a rare injury in the paediatric population. It can occur after high energy trauma, but also after lower energy injuries especially in younger children. Posterior dislocation is the most common pattern of hip dislocation. In most cases, closed reduction is successful, but occasionally open reduction is required to achieve concentric reduction. The aim of our study was to present the 10-year experience from a Level-1 Trauma Paediatric Hospital and to comment on how our experience correlates with the current literature.

Patients And Methods: This is a retrospective case series of all paediatric patients (< 16 years old) with a traumatic hip dislocation presented and/or treated at our institution, between the 1 of January 2010 and 31 August 2020.

Results: Thirteen cases of traumatic hip dislocation were identified. There were 7 females. The mean age was 9.8 years. Typically, younger patients were involved in lower energy injuries. The direction of hip dislocation was posterior in ten cases. Associated injuries were seen in eight patients. All cases underwent closed reduction, which was successful in nine cases. Mean time to reduction was 6.8 hours. Post reduction imaging with CT and/or MRI was performed in all cases. There was residual subluxation in three cases, requiring open reduction. In one case with unrecognised undisplaced physeal injury, closed reduction resulted in a Delbet type 1 hip fracture. Two cases developed avascular necrosis (AVN).

Conclusions: Traumatic paediatric hip dislocation is a rare injury. A target of 6 hours for reduction should be employed as this will reduce the risk of AVN in those who have not permanently damaged the vessels at the time of injury. We advocate all attempts for closed reduction to be performed in an operating theatre with the use of an image intensifier to help identifying associated injuries and confirm concentric reduction. If closed reduction fails, open reduction is required. Post-reduction MRI is an important adjunct to recognise associated soft tissue injuries. Follow up of patients should continue for 2 years as a minimum to help detect AVN.