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Difficulty: Very hardOrthopedic Surgery

An unrestrained 24-year-old male driver is transported to the emergency department following a severe front-end motor vehicle collision. Primary survey reveals a hemodynamically stable patient with an isolated right lower extremity injury. The right leg is visibly shortened, adducted, and internally rotated. The patient complains of intense right hip pain and an inability to feel the top of his right foot. Subsequent imaging during his care reveals an incongruent joint space requiring definitive operative intervention. Arrange the following steps in the correct chronological order for the optimal, evidence-based management of this patient's injury.

  1. 1Perform a focused neurovascular examination to evaluate sciatic nerve function
  2. 2Obtain a portable anteroposterior radiograph of the pelvis
  3. 3Perform emergent closed reduction of the hip under procedural sedation
  4. 4Obtain a post-reduction computed tomography (CT) scan of the pelvis
  5. 5Perform open surgical joint debridement and extraction of incarcerated fragments

Answer

The correct chronological sequence is: Neurovascular examination → AP Pelvis Radiograph → Closed Reduction → CT Scan → Open Surgery.
The correct chronological management of a traumatic posterior hip dislocation balances rapid intervention with diagnostic safety. A neurovascular exam must always precede orthopedic intervention to establish a baseline. Plain radiography is then required to confirm the dislocation and rule out a femoral neck fracture, which is an absolute contraindication to closed reduction. Once cleared, emergent closed reduction is prioritized over advanced imaging to decompress the vascular supply within a 6-hour window, minimizing avascular necrosis risk. A CT scan is the standard of care following reduction to evaluate for occult acetabular fractures or loose bodies. Finally, because the stem notes an incongruent joint, open surgical debridement is required to remove the incarcerated fragments identified on CT.

Step-by-Step Solution

1
Perform a focused neurovascular examination to evaluate sciatic nerve function
Establishes a baseline neurological status for the lower extremity.
Posterior hip dislocations place the sciatic nerve (especially the peroneal division) at high risk for stretch neuropraxia. Documenting this deficit before any intervention is clinically and medicolegally essential.
2
Obtain a portable anteroposterior radiograph of the pelvis
Confirms posterior hip dislocation and assesses bone integrity.
An initial plain radiograph is mandatory to rule out a concomitant femoral neck fracture. Attempting a closed reduction on a fractured femoral neck can cause catastrophic displacement and destroy the remaining blood supply.
3
Perform emergent closed reduction of the hip under procedural sedation
Restores anatomical alignment of the hip joint.
Time is tissue. The hip must be reduced emergently (within ≤6\leq 6 hours) to relieve tension on the medial circumflex femoral artery. Delaying this step increases the risk of avascular necrosis (AVN) of the femoral head.
4
Obtain a post-reduction computed tomography (CT) scan of the pelvis
Provides high-resolution cross-sectional imaging of the reduced joint.
CT is strictly reserved for the post-reduction phase to evaluate for subtle acetabular wall fractures or osteochondral fragments in the joint space that could block a perfect, concentric reduction.
5
Perform open surgical joint debridement and extraction of incarcerated fragments
Removes mechanical blocks and ensures a fully congruent hip joint.
Indicated specifically because the patient's joint space remains incongruent, implying that loose bodies identified on the CT scan must be surgically extracted to prevent rapid joint destruction.

Key Concept

The management sequence for traumatic posterior hip dislocation prioritizes immediate neurovascular assessment followed by urgent closed reduction to prevent avascular necrosis, deliberately deferring advanced CT imaging until after the joint is reduced.
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Orthopedic Surgery

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