summary Hip dislocations are traumatic hip injuries that result in femoral head dislocation from the acetabular socket. Diagnosis can be made with hip radiographs to determine the direction of dislocation and CT scan studies to assess for associated injuries. Treatment is urgent reduction to minimize risk of avascular necrosis followed by CT scan to assess for associated injuries that may require surgical treatment (loose bodies, femoral head fractures, acetabular fractures). Epidemiology Incidence rare, but high incidence of associated injuries Etiology Pathophysiology mechanism is usually young patients with high energy trauma Pathoanatomy Hip joint inherently stable due to bony anatomy soft tissue constraints including login to view 3 more bullets Classification Simple vs. Complex simple pure dislocation without associated fracture complex dislocation associated with fracture of acetabulum or proximal femur Anatomic classification posterior dislocation (90%) occur with axial load on femur, typically with hip flexed and adducted login to view 1 more bullet position of hip determines associated acetabular injury login to view 1 more bullet associated with login to view 5 more bullets anterior dislocation associated with femoral head impaction or chondral injury occurs with the hip in abduction and external rotation inferior ("obturator") vs. superior ("pubic") login to view 4 more bullets Presentation Symptoms acute pain, inability to bear weight, deformity Physical exam ATLS 95% of dislocations with associated injuries posterior dislocation (90%) most common associated with posterior wall and anterior femoral head fracture hip and leg in slight flexion, adduction, and internal rotation detailed neurovascular exam (10-20% sciatic nerve injury) examine knee for associated injury or instability chest X-ray ATLS workup for aortic injury anterior dislocation hip and leg in extension, abduction, and external rotation Imaging Radiographs recommended views AP cross-table lateral login to view 2 more bullets obtain AP, inlet/outlet, judet views after reduction findings loss of congruence of femoral head with acetabulum disruption of shenton's line login to view 1 more bullet anterior dislocation login to view 2 more bullets posterior dislocation login to view 3 more bullets CT helps to determine direction of dislocation, loose bodies, and associated fractures anterior dislocation posterior dislocation post reduction CT must be performed for all traumatic hip dislocations to look for femoral head fractures loose bodies acetabular fractures MRI controversial and routine use is not currently supported useful to evaluate labrum, cartilage and femoral head vascularity Treatment Nonoperative emergent closed reduction within 12 hours indications login to view 1 more bullet contraindications login to view 1 more bullet Operative open reduction and/or removal of incarcerated fragments indications login to view 5 more bullets ORIF indications login to view 5 more bullets arthroscopy indications login to view 3 more bullets Techniques Closed reduction perform with patient supine and apply traction in line with deformity regardless of direction of dislocation must have adequate sedation and muscular relaxation to perform reduction assess hip stability after reduction post reduction CT scan required to rule out femoral head fractures intra-articular loose bodies/incarcerated fragments login to view 2 more bullets post-reduction for simple dislocation, follow with protected weight bearing for 4-6 weeks Open reduction approach posterior dislocation login to view 1 more bullet anterior dislocation login to view 1 more bullet technique may place patient in traction to reduce forces on cartilage due to incarcerated fragment or in setting of unstable dislocation repair of labral or other injuries should be done at the same time Complications Post-traumatic arthritis up to 20% for simple dislocation, markedly increased for complex dislocation Femoral head osteonecrosis 5-40% incidence Increased risk with increased time to reduction Sciatic nerve injury 8-20% incidence associated with longer time to reduction Recurrent dislocations less than 2%