Working Diagnosis:
Posterior hip dislocation with subtle posterior acetabular fracture, femoral head chondral injury, and labral tear, status post concentric closed reduction with sedation.

Treatment:
The patient followed-up in clinic at 3 days, 2 weeks, 1.5 months, 2.5 months, and 4 months post-injury. The patient was initially made non-weight bearing with total hip precautions (No hip flexion past 90 degrees, no hip adduction past midline, no hip internal rotation) for 4 weeks.

An MRI was obtained at 4 weeks post-injury Case Photo #2 . Most notably, there were no signs of avascular necrosis on his MRI. At 4 weeks post-injury, after his MRI was reviewed, he was referred to physical therapy and his weight bearing status was gradually progressed. The patient achieved full weight bearing at 6 weeks post-injury.

An x-ray of the right hip was repeated at 2.5 months post-injury and was normal, without radiographic evidence of avascular necrosis. He continued physical therapy and was cleared for full activity and sports 4 months post-injury. He will return to clinic at about one year post-injury for re-evaluation.

Outcome:
The patient returned to sport with full activity clearace 4 months post-injury after treatment/rehabilitation.

Author's Comments:
Traumatic hip dislocations are rare in youth athletes. In adults, they are most commonly posterior and associated with high-energy trauma, such as motor vehicle accidents. This injury has also been reported, though uncommon, in sporting activities, like American football. In youth athletes, they may be seen with far less significant forces. Prompt recognition and reduction of traumatic hip dislocation is key. There is a lack of evidence-guided management once they have been reduced. Further management, including return to activities, repeat imaging to monitor for developing avascular necrosis (including how often MRI should be repeated since x-rays are more convenient to repeat, but have lower sensitivity than MRI in detecting avascular necrosis), and follow-up is not well-defined.

Editor's Comments:
Traumatic posterior hip dislocation is an uncommon injury in children and adolescent athletes and requires an emergent closed reduction. Prompt reduction (within 6 hours) and the concentricity of reduction are important for long term prognosis. Delayed or incomplete reduction leads to an increased risk of avascular necrosis. Incomplete reductions may occur when soft tissues or bony fragments become entrapped and block the reduction. CT and MRI are useful in evaluating for associated injuries such as associated acetabular fractures, intra-articular bony fragments or soft tissue interposition. In younger athletes, MRI offers a further advantage of evaluating associated cartilage fractures that may not be appreciated on x-ray or CT (4,5). After a successful concentric reduction has been confirmed, treatment may include a hip abduction orthosis, total hip precautions, and protected weight bearing status for 4-6 weeks. Long term follow up is recommended as post injury complications may occur. Children with an open triradiate cartilage and associated injury to the triradiate cartilage are at risk of developing acetabular dysplasia. Osteonecrosis is another complication that can occur after a traumatic posterior hip dislocation and may not be seen on radiographs in the initial healing stages (5).

References:
1) Clausen JD, Winkelmann M, Macke C, et al. A Rare Case of a Traumatic Posterior Hip Dislocation in a 3-Year-Old Boy: A Case Report and Review of the Literature. Case Reports in Orthopedics. 2020;2020:1-6.

2) Day M, Shirley E, Joughin E. Traumatic Hip Dislocation - Pediatric. OrthoBullets website. 2018. https://www.orthobullets.com/pediatrics/4017/traumatic-hip-dislocation--pediatric. Accessed Apr 15, 2020.

3) Figueras Coll G, Torrededia Del Rio L, Garcia Nuno L, et al. Traumatic Hip Dislocation in Childhood. Hip Int. 2010;20(4):524-8.

4) Thanacharoenpanich S, Bixby S, Breen MA, et al. MRI is Better than CT Scan for Detection of Structural Pathologies After Traumatic Posterior Hip Dislocaitons in Children and Adolescents. J Pediatr Orthop. 2020;40(2):86-92.

5. Sink, EL.Kim, YJ. Fractures and Traumatic Dislocations of the Hip in Children. WeinsteinSL, Flynn J. ed. Lovell and Winter's Pediatric Orthopaedics. Vol 2. 7th ed. Philadelphia:Lippincott Williams and Wilkins; 2014:954-983.

Return To The Case Studies List.