Trauma X-ray - Lower limb

Hip dislocation

Hip dislocation (dislocation of the femoral head from the acetabulum) is most frequent following total hip replacement (THR). Dislocation is usually in a posterior direction which clinically leads to leg shortening, with flexion and internal rotation at the hip (note - hip fractures usually cause external rotation).

Hip dislocation may be accompanied by fracture of the acetabulum, or significant soft tissue injuries not visible with X-ray.

Standard views

Anterior-Posterior (AP) pelvis and Lateral hip. Both views should be carefully viewed to look for an accompanying fracture of the acetabular rim.

Key points

  • Hip dislocation can be accompanied by fractures, or soft tissue injury not visible with X-ray
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Hip dislocation - AP

  • The femoral head lies superior and lateral to the acetabulum
  • No associated fracture is visible in this case but significant soft tissue injury is likely
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Hip dislocation - Dislocated THR

  • Patient with Total Hip Replacement (THR)
  • The ball of the femoral component is displaced from the cup of the acetabular component

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