Anatomy Msk · Year 1 · from Anatomy Msk
Case 2: Posterior Hip Dislocation
Clinical Image
Source: Wikimedia Commons - Hip Dislocation - CC BY-SA 3.0
Case Presentation
A 28-year-old unrestrained driver is brought to the trauma center after a head-on motor vehicle collision. He reports his knee struck the dashboard upon impact. He complains of severe left hip pain and cannot move his left leg. Primary survey is unremarkable except for the obvious left lower extremity deformity. Secondary survey reveals the left leg is shortened, adducted, internally rotated, and flexed at the hip - the classic position of posterior hip dislocation. There is no open wound. Neurovascular examination reveals diminished sensation over the dorsum of the left foot, and he is unable to dorsiflex his ankle (foot drop). Palpable dorsalis pedis and posterior tibial pulses are present. AP pelvis radiograph confirms posterior dislocation of the left femoral head without visible acetabular fracture. The hip is reduced emergently in the trauma bay using the Allis maneuver with the patient under procedural sedation. Post-reduction examination shows improvement in sciatic nerve function with return of ankle dorsiflexion. CT scan confirms concentric reduction and reveals a small posterior wall acetabular fracture. He is kept non-weight-bearing and managed conservatively.
Key Learning Points
- Posterior hip dislocations account for 90% of traumatic hip dislocations, typically from dashboard injury
- The sciatic nerve courses posterior to the hip joint and is injured in 10-20% of posterior dislocations
- Classic presentation: shortened, adducted, internally rotated, and flexed hip
- The posterior capsule and posterior acetabular rim are weaker than the anterior structures
- Time to reduction is critical; rates of avascular necrosis and sciatic nerve injury increase after 6 hours