Risk factors and long-term outcomes in anterior iliac and obturator hip dislocation

PURPOSE: Traumatic anterior hip dislocation is a severe but poorly studied injury. This study aimed to analyze characteristics, risk factors and prognostic factors regarding long-term morbidity and outcomes in patients who had sustained traumatic anterior hip dislocation.

METHODS: Demographics, injury mechanism, and treatment-related characteristics of patients with anterior hip dislocations at three level-one trauma centers from 2009-2023 were analyzed. Acetabular and femoral morphology were assessed using CT scans to identify anatomical risk factors. Incidence of avascular necrosis (AVN), post-traumatic osteoarthritis (PTOA), further complications, return to work and sports, and patient-reported outcomes (PROMs), including Tegner Activity Scale (TAS) and modified Harris Hip Score (mHHS) were recorded at the follow-up.

RESULTS: Out of 196 patients with traumatic hip dislocations, 19 anterior dislocations (12 iliac anterosuperior and 7 obturator) were identified. Ipsilateral knee injuries occurred in 36.8%, and 73.7% had concomitant femoral head or acetabular rim fractures. Obturator dislocations were commonly simple dislocations, while iliac dislocations involved more complex associated fractures often requiring surgery. Acetabular anteversion and cam-type femoroacetabular impingement (FAI) were identified as risk factors. Twelve patients (63%) were available for follow-up (mean 8.33 ± 5.05 years). The majority demonstrated good to excellent mHHS (mean 86.9), and minimal TAS decrease (5.33 to 4.67). AVN was not observed, and only one patient required hip arthroplasty following PTOA.

CONCLUSION: Anterior hip dislocations commonly result from high-energy "dashboard" injuries, with acetabular anteversion and cam-type FAI morphology being contributing risk factors. Long-term functional outcomes were favorable, with low rates of avascular necrosis or osteoarthritis, independent of type and complexity of the dislocation.