A 45-year-old woman sustains a posterior hip dislocation with a posterior wall acetabular fracture after a road traffic accident. On examination, the hip is flexed, adducted and internally rotated, and there is foot drop on the same side. The nerve most commonly injured in this pattern of acetabular fracture-dislocation is:

• A Femoral nerve
• B Sciatic nerve (especially peroneal division) ✓
• C Obturator nerve
• D Superior gluteal nerve

Explanation

Posterior hip dislocation and posterior wall acetabular fractures are associated with sciatic nerve injury in 10–20% of cases. The peroneal division of the sciatic nerve is more vulnerable due to its posterior and lateral course, producing foot drop (weak dorsiflexors), loss of toe extension, and loss of sensation over the dorsum of the foot. The femoral nerve (A) is injured in anterior dislocations. The obturator nerve (C) is injured in obturator-type dislocations or transverse + posterior wall patterns. Hip reduction within 6 hours minimises the risk of avascular necrosis and may allow nerve recovery.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.