Avascular necrosis of the femoral head after traumatic posterior hip dislocation with and without acetabular fracture

Purpose Traumatic hip dislocation can be isolated or associated with acetabular fracture. Both injuries require emergency reduction of the dislocated hip. Avascular necrosis of the femoral head (AVN) is a potential complication that accompanies these severe injuries. Our objective is to identify the risk factors that cause AVN. Methods We retrospectively analyzed 44 patients with traumatic hip dislocations (Group A) and patients with posterior fracture-dislocation of the acetabulum (Group B). The average follow-up was 5.38 years in Group A, 5.59 years in Group B. We used the Thompson-Epstein classification for hip dislocation and the Harris Hip Score (HHS) for evaluating final outcomes. Results In Group A, we analyzed 21 patients with isolated posterior hip dislocation. We had one (4.76%) case of AVN. In Group B, we analyzed 23 patients with posterior acetabular fracture-dislocation. We had eight (34.78%) patients with AVN (p = 0.016,p < 0.05). With hip reduced 6-12 h after injury, we had AVN in one (4.34%) patient, with reduction 12-24 h, AVN was present in two (8.69%), while in hip reduction done after 24 h of injury, AVN was present in five (21.73%) patients (p = 0.030,p < 0.05). Conclusion An essential prerequisite for the prevention of AVN of the femoral head after hip dislocation is emergency hip reduction. In acetabular fracture-dislocation, emergency hip reduction, anatomical reduction of the acetabular fracture and early stable osteosynthesis are also important. Main factor affecting the development of AVN is late reduction of the hip.

Automated summary

Traumatic hip dislocation, particularly in combination with acetabular fracture, can lead to avascular necrosis of the femoral head. This study retrospectively analyzed patients with traumatic hip dislocations and posterior fracture-dislocation of the acetabulum, identifying the risk factors for avascular necrosis. The findings highlight the importance of emergency hip reduction, anatomical reduction of the acetabular fracture, and early stable osteosynthesis in preventing avascular necrosis. The main factor affecting avascular necrosis development is delayed hip reduction.