Hip Dislocations

Direct trauma, especially road traffic accidents and falls, are the most common cause of hip dislocation. Hip dislocation may also be caused by congenital dislocation and acetabular or femoral head dysplasia.

• A violent force is usually required to dislocate an adult's hip but children may sustain a hip dislocation following relatively minor trauma.
• Hip dislocations are more easily missed if there is an associated femoral shaft fracture.
• Dislocations in children must be reduced gently in order to avoid injury to the femoral epiphysis.
• Traumatic dislocations are described as being anterior, posterior or central.¹

• Caused by major force to a flexed knee and hip, e.g. when knees strike the dashboard in a road traffic accident. Other serious injuries are also often present, including fractures of the posterior acetabular or femoral shaft.
• Account for the majority of hip dislocations. The frequency has decreased with the increased use of belts and air bags.
• Affected leg is shortened and internally rotated with flexion and adduction at the hip. This appearance may not occur if there is also a femoral shaft fracture.
• Diagnosis is usually obvious on AP x-ray. Lateral views may be needed to exclude a hip dislocation with certainty.
• Initial treatment:
  • Resuscitation and deal with ABC priorities first
  • Analgesia: pain is severe
  • Refer for reduction under general anaesthetic
  • 'Allis technique' for reduction:²
    • Probably easiest and safest to place the anaesthetised patient on the floor
    • An assistant holds the pelvis down.
    • Flex hip and knee both to 90 degrees and correct adduction and internal rotation deformities
    • Grip the patient's lower leg between your knees and grasp patient's knee with both hands
    • Lean back and then lever the knee up, pulling the patient's hip upwards
    • A clunk confirms successful reduction
    • X-ray to confirm reduction
• Complications include:
  • Sciatic nerve injury: pain in the distribution of the sciatic nerve, loss of sensation in the posterior leg and foot and loss of dorsiflexion (peroneal branch) or plantar flexion (tibial branch) of the foot.
  • Vascular injury: not as frequent as with anterior dislocations.
  • Avascular necrosis of the femoral head: risk increases the longer the hip is dislocated.³
  • Secondary osteoarthritis.

• Less common
• Causes pain in the hip and inability to walk or adduct the leg
• The leg is externally rotated, abducted, and extended at the hip
• Complications included damage to the femoral nerve, artery and vein:
  • Injury to the femoral nerve may occur, resulting in paralysis and numbness in the femoral nerve distribution
  • Injury to the femoral artery may produce arterial insufficiency in the leg
• Initial treatment:
  • Provide analgesia
  • Refer for reduction under general anaesthetic

• Head of the femur is driven through the fractured acetabular floor following a fall or force directed along the length of the femur, e.g. car dashboard.
• Leg deformity depends on nature and extent of penetration into the pelvis. Leg is shortened, abducted or adducted, and internally or externally rotated.
• Diagnosis is usually obvious on AP pelvis x-ray.
• Initial treatment:
  • Treat associated injuries, shock and give analgesia
  • Refer to orthopaedic team immediately

• Relatively common and may follow minor trauma
• X-ray to confirm posterior dislocation of hip prosthesis
• Initial management:
  • Provide analgesia (IV opiate)
  • Refer to orthopaedics for manipulation under general anaesthetic

• Often accompanies traumatic hip dislocation following violent injury such as falls or blows to the hip
• Most often transverse or posterior rim fracture
• May lead to severe haemorrhage, damage to the sciatic nerve, myositis ossificans and osteoarthritis
• Additional x-rays (e.g. 45 degree oblique views) or CT scanning may be required for diagnosis
• Initial management:
  • Resuscitate and deal with ABC resuscitation priorities first
  • Analgesia as required
  • Refer to orthopaedics: requires traction, protected weight-bearing and sometimes internal fixation

• Mortality associated with hip dislocation is mainly due to associated injuries of the pelvis, head, or thorax.
• Local venous injury and prolonged immobilisation lead to a high risk of deep venous thrombosis, pulmonary embolus and pneumonia.
• Osteoarthritis: more common in older patients.
• Avascular necrosis is common. The incidence is increased with delays in reduction beyond 6 hours, with open reduction and early weight bearing. Usually requires replacement with a prosthetic hip.
• Injury to either the femoral or sciatic nerve: usually consists of a transient lesion with recovery of function. Permanent injury may occur but is uncommon.
  • Injury to the sciatic nerve: especially posterior dislocations and may occur during the initial trauma or during reduction.
  • Anterior dislocations occasionally cause injury to the femoral artery or nerve.
• Recurrent dislocation: common because of damage to supporting ligaments
• Ligament injury to the knee and/or other fractures

Varies according to the type of dislocation and presence of associated fractures and other injuries.