Hip Dislocations (Subscribe)  

Posterior Hip Dislocations
Posterior hip dislocations are the most common. The usual cause is a motor vehicle accident with the passenger's knee hitting the dashboard and forcing the femoral head out of the acetabulum posteriorly. The limb is shortened, and the hip flexed, the foot is in internal rotation.
Anterior Hip...

* usually posterior
o hip flexed, knee hits dashboard during deceleration
* superior migration of femoral head
* +/- acetabular fx

Traumatic hip dislocations (not including those after hip arthroplasty) are almost always due to high energy trauma. Unrestrained MVA passengers are more likely to have a hip dislocation that restrained passengers. The classic mechanism for posterior dislocation is during a dashboard injury (hip and knee are in flexion...

Incidence
Young men
Post:Ant 9:1
Aetiology
High velocity injury
- Head direction at impact decides direction of dislocation
Ant Dislocation
ER & Abducted leg
- FLEX = Inf Dislocation
- EXT = Pubic Dislocation
Post Dislocation
Axial compression of Adducted leg
- More Flexion cause pure dislocation, °#

Wheeless' Textbook of Orthopaedics
- hip dislocations are typically caused by high-energy trauma, usually from motor-vehicle accidents. - they occur most frequently in young patients; - types of dislocations: - anterior dislocation ...

Case presentation of recurrence of hip dislocation after initial traumatic posterior dislocation. At arthrotomy the posterosuperior acetabular labrum was found to be disrupted and a pouch was formed between the posterior acetabular wall and the short rotator muscles.
Rashleigh-Belcher & Cannon JBJS B Vol68 # 3 1986