Hip dislocations are true orthopedic emergencies. The Emergency
Physician must be capable of reducing a dislocated hip. Neurovascular
damage to the hip and leg is a consequence of a hip dislocation.
The complication of avascular necrosis is time-dependent. The longer a hip is dislocated, the higher
the incidence of avascular necrosis. Dislocation of a hip for
more than 6 hours almost universally results in this devastating
The main etiologies of a hip dislocation are traumatic dislocations
of a normal hip, mechanical dislocations of a prosthetic hip, spontaneous
dislocations, and pathologic dislocations. Less impressive mechanisms
may result in hip dislocations in the young and the elderly. A simple
fall from standing may dislocate a geriatric hip. Dislocations may
occur with minor force in children, as during athletic activities.
Many techniques have been described to reduce dislocated hips.1–7 The
Emergency Physician must be familiar with some of these methods
and how to apply them appropriately to optimize patient management
and outcome. Dislocations of both normal and prosthetic hips are
seen in the Emergency Department. Dislocations of prosthetic hips
are now more common than those of normal hips.8 While these
are not associated with avascular necrosis, the pressure from the
dislocated prosthetic head may result in other neurovascular complications.
Ball-and-socket joints are inherently stable. The strong muscles,
ligaments, and fibrous joint capsule of the hip reinforce this innate
stability. Consequently, in the average adult, a great deal of force
must be transmitted to dislocate the hip. This is significant, as
the patient with a hip dislocation may have other life-threatening
injuries that take precedence over the management of the hip dislocation.
The mortality associated with a hip dislocation results from associated
injuries of the head, thorax, or pelvis.
Hip dislocations are classified into anterior, posterior, and
central based upon the relationship of the dislocated femoral head
to the acetabulum. Anterior hip dislocations occur with the leg
in a neutral or abducted position. The femoral head is pushed anterior
to the coronal plane of the acetabulum. These patients present in
extreme pain with the hip and knee flexed 90 degrees. The leg will
be held in external rotation. A slight shortening of the leg may
be noted, but this is difficult to detect with the knee in flexion.
There are three subtypes of an anterior hip dislocation: anterior obturator,
anterior iliac, and anterior pubic. The femoral head displaces medially
and lies in the obturator canal in anterior obturator dislocations.
The femoral head moves superiorly and lies over the iliac wing in
anterior iliac dislocations. The femoral head moves inferiorly over
the pubic ramus in anterior pubic dislocations.
Posterior hip dislocations are the most common type. They account
for nearly 90 percent of all hip dislocations. This is because the
posterolateral half of the femoral neck lies outside the joint capsule
and the weaker posterior support of the hip. Posterior dislocations
result from force ...