Hip dislocation

Question 1

What is the nerve most at risk from posterior hip dislocation?

Answer 1

Sciatic nerve

Question 2

State two (2) reasons why there is increased morbidity in native hip dislocations compared with prosthetic hip dislocations.

Answer 2

Prosthetic hips have femoral head removed hence no risk of avasc necrosis
Higher force required to dislocate native hip
Deep sedation +/- GA required for naive reduction

Question 3

Techniques for hip relocation

Answer 3

Allis = Stand on bed, 90 degs, traction
Captain morgan = stand side of bed with knee over your leg
Whistler = Stand bedside, leg under knee, on top of contralateral, press down on ankle

Question 4

What recommendations can reduce recurrence of hip dislocation?

Answer 4

Avoid flexing hip >90
Avoid complete ABduction (Charnley pillow)
Avoid internal rotation
Knee splint (discourage hip flexion)

Question 5

What are the rates of avascular necrosis if relocation is under 6 hours versus over?

Answer 5

Reduction < 6 hours: 5% avascular necrosis
Reduction > 6 hours: 50% avascular necrosis

Question 6

What nerve is most likely to be injured in anterior hip dislocation?

Answer 6

Femoral