Edited by Cameron Egan and Jeffrey “Spud” Olson - 7/1/2021
Descriptors
Dislocations can be simple (without associated fracture) or complex (associated fracture of acetabulum or proximal femur).
Posterior dislocation (most common) vs. anterior dislocation
Exam Pearls
Often high energy and associated with other injuries (ATLS protocol).
Posterior dislocations - the leg will be resting in slight flexion, adduction, and internal rotation.
Anterior dislocations - the leg will be resting in extension, abduction, and external rotation
Detailed and documented neurovascular exam in trauma bay BEFORE reduction.
Examine knee in trauma bay
Workup
Radiographs: AP pelvis, Cross-table lateral
AFTER reduction - repeat AP pelvis, cross-table lateral, inlet/outlet, and judet views
Other imaging: CT hip to include proximal femur - Look for loose bodies within joint, acetabular fractures, femoral head fractures
Labs: Complex dislocations - pre-operative labs
Other: None
Management
Need for acute intervention:
Yes, immobilization with reduction. Need conscious sedation (ask ED for this immediately so they can plan - it can take a while). Should be reduced in <12 hours. Wait until patient is very relaxed before attempting reduction.
See Hip dislocation (posterior)
See Hip dislocation (anterior)
If loose bodies or incarcerated intra-articular fragments after reduction - place distal femur skeletal traction
Weight-bearing and range of motion: Simple dislocations - protected weightbearing. Complex dislocations - Generally NWB depending on fracture pattern
Type of immobilization: Knee immobilizer
Admission or discharge status:
Simple dislocation with no other injuries - ED obs for PT evaluation maintaining weight bearing restrictions.
Complex dislocation with no other injuries - Admit to ortho
Dislocations with significant polytrauma - Generally admitted to general surgery
Anticoagulation: Lovenox 40mg daily
Antibiotics: Most commonly closed injury - none
Surgical Indications
Absolute: Unable to perform closed reduction. Incarcerated fragments/intra-articular loose bodies after closed reduction.
Relative: Femoral head fractures
Not an indication: Reduced native joint without associated fracture