THA Dislocation

Question 1

What are the two most common reasons for revision THA?

Answer 1

1) Infection

2) Dislocation (instability)

Question 2

What are indications for revision THA in recurrent dislocations?

Answer 2

> 2 dislocations with:

1) Eccentric poly wear
2) Malposition (retroverted cup, vertical cup)
3) Hardware failure

Question 3

What is the most common complication of isolated polyethylene exchange with bone grafting for poly wear or osteolysis?

Answer 3

Post-op instability (25%)

Question 4

What are techniques used to prevent dislocation in revision THA for instability?

Answer 4

1) Realign malpositioned components
2) Larger head
3) Distalize trochanter
4) Constrained liner

Question 5

What situation is appropriate for revision of a total hip arthroplasty to a constrained acetabular liner?

Answer 5

1) recurrent dislocations due to unrepairable soft-tissue insufficiency from lack of abductor function or capsular attenuation
2) severe cognitive disorders
3) late dislocations with well positioned components.