Traumatic Hip Dislocation
Classification systems
- Direction: posterior (the great majority), anterior, or central with an acetabular fracture
Mechanism
A dashboard injury with the hip flexed and adducted drives the head posteriorly; an abducted externally rotated hip at impact drives it anteriorly. It takes considerable force in a normal hip, so associated acetabular, femoral head and knee injuries are common — the knee that struck the dashboard must always be examined.
Age considerations
- Paediatric
- Can occur with lower energy because of soft tissue laxity; the concern is osteonecrosis of the developing femoral head and the need for prompt reduction, along with a search for a physeal separation mimicking dislocation.
- Young adult
- The typical patient. Time to reduction is the modifiable factor influencing osteonecrosis risk, and post-reduction cross-sectional imaging is mandatory to exclude an incarcerated fragment or a femoral head fracture.
- Elderly
- Consider a periprosthetic dislocation in a patient with a hip replacement, which is a different problem centred on component position, soft tissue tension and abductor function.
Management options
Urgent closed reductionshowhide
Indication
Every acute traumatic hip dislocation without a contraindication such as an ipsilateral displaced femoral neck fracture.
Implant design notes
No implant. Reduction under general anaesthesia with full muscle relaxation; skin or skeletal traction may hold an unstable hip afterwards.
Approach
Closed reduction in theatre under anaesthesia; avoid repeated forceful attempts in the emergency department.
Steps overview
- Document sciatic nerve function, particularly the peroneal division, before any manipulation
- Exclude an ipsilateral femoral neck fracture on radiographs before attempting reduction
- Reduce under general anaesthesia with relaxation, using in-line traction with the hip and knee flexed and gentle rotation
- Confirm a concentric reduction radiographically and reassess neurology
- Obtain cross-sectional imaging after reduction to look for intra-articular fragments and an acetabular or head fracture
- Assess stability and apply traction or a knee immobiliser if the hip is unstable
- Mobilise with protected weight bearing and monitor for osteonecrosis over the following two years
Notes
Reduction is time-critical; osteonecrosis risk rises with delay. Repeated forceful attempts in an unrelaxed patient risk iatrogenic femoral neck fracture.
Resident summary compiled from standard orthopaedic trauma teaching; verify against your departmental protocol.
Open reduction with treatment of associated injuryshowhide
Indication
Irreducible dislocation, non-concentric reduction from an incarcerated fragment, associated displaced acetabular or femoral head fracture, or an ipsilateral femoral neck fracture.
Implant design notes
Screws for a femoral head fragment placed countersunk beneath the articular surface, plus acetabular fixation as required. A surgical dislocation approach with a trochanteric osteotomy allows full inspection of the head while protecting its blood supply.
Approach
Posterior Kocher-Langenbeck approach for posterior wall pathology with sciatic nerve protection, or a surgical hip dislocation approach with trochanteric osteotomy for head lesions.
Steps overview
- Plan from post-reduction cross-sectional imaging, defining every fragment
- Choose the approach that gives access to the pathology while protecting the medial circumflex femoral artery
- Expose, remove loose bodies and irrigate the joint
- Reduce and fix the femoral head fragment with countersunk screws where it is significant and weight bearing
- Fix an associated acetabular wall or column fracture to restore stability
- Confirm concentric reduction and stability through a range of movement
- Close, and rehabilitate with protected weight bearing and osteonecrosis surveillance
Notes
Preserve the medial circumflex femoral artery throughout; it is the head's principal supply and the reason a surgical dislocation approach is designed the way it is.
Resident summary compiled from standard orthopaedic trauma teaching; verify against your departmental protocol.
Viva pearls
- Time to reduction is the modifiable risk factor for osteonecrosis — treat it as an emergency.
- Exclude an ipsilateral femoral neck fracture before you pull; reducing through an unrecognised neck fracture is a disaster.
- Document sciatic nerve function before and after reduction, with particular attention to the peroneal division.
- Always obtain post-reduction cross-sectional imaging: an incarcerated fragment produces a subtly non-concentric reduction.
- Examine the knee — the same dashboard force injures the posterior cruciate ligament and the patella.
- A posterior dislocation presents with the limb flexed, adducted and internally rotated; an anterior dislocation with it extended, abducted and externally rotated.
Sources for further reading
- Rockwood and Green's Fractures in Adults — hip dislocations and femoral head fractures
- Standard operative orthopaedics textbook — traumatic dislocations of the hip
- Regional anatomy text — blood supply of the femoral head and surgical hip dislocation
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Resident-authored study summary in original wording, not reproduced from copyrighted source text.