Traumatic Hip Dislocations in the Pediatric Patient: Injury Patterns, Need for Axial Imaging, Outcomes, and Selective Hip Arthroscopy

Background: Traumatic hip dislocations are uncommon injuries in the pediatric population. Injury recognition and prompt closed reduction is standard of care. The purpose of this study is to describe injury patterns, treatment (including hip arthroscopy), and patient reported outcomes of traumatic hip dislocation in pediatric patients. Methods: A retrospective review was performed of all patients less than 18 years of age treated for a traumatic hip dislocation between 2011 – 2017 at a single center. Chart and radiographic review were performed, and patients were contacted to obtain outcome scores, including the Harris hip score (HHS) and hip outcome score (HOS). Results: 23 patients, 18 males and 5 females, with a mean age of 11.3 years (range 4 – 16) were included. The most common mechanisms of injury were motor vehicle crashes (8), football (7), and falls (3). The direction of hip dislocation was posterior (21) and obturator (2). Twenty patients had a CT to assess the hip reduction and associated injuries and 15 (75%) had a posterior wall acetabular fracture and 6 (30%) had an incarcerated fragment within the joint. 5 patients had an MRI and all had an associated posterior wall fracture and posterior labral tear. Fourteen patients were treated non-operatively. Patient-reported outcome scores were obtained in 10 patients (71%). Mean HOS-ADL, HOS-Sport, and mHHS were 75 (69 – 76), 32 (18 – 36), and 97 (85 – 100) respectively at a mean of 40 months after injury. Nine patients were treated operatively, including 5 patients with hip arthroscopy. Patient-reported outcome scores were obtained in 7 patients (78%). Mean HOS-ADL, HOS-Sport, and mHHS were 69 (50 – 76), 30 (14 – 36), and 86 (59 – 100) respectively at a mean of 34 months after surgery. Conclusion: Traumatic hip dislocations in the pediatric population occur most frequently as isolated orthopaedic injuries in association with posterior wall acetabular fractures. Incarcerated fragments occurred in 30% of the patients, yet were commonly not recognized on plain radiographs alone. Axial imaging should be routinely obtained following reduction. Selective hip arthroscopy after traumatic hip dislocations is a viable less invasive method for treatment of incarcerated fragments and labral injury. Key Concepts Pediatric and adolescent traumatic hip dislocations are rare and most often occur as an isolated orthopedic injury. Advanced axial imaging, preferably an MRI, should be obtained after reduction in all patients to evaluate for intra-articular pathology. Without incarcerated fragments, patients may be treated non-operatively with good mid-term functional outcome scores Selective hip arthroscopy may be effectively utilized in patients with intra-articular blocks to reduction and significant labral pathology. Level of Evidence: IV