Hip Dislocation in Emergency Medicine Workup
- Author: Stephen R McMillan, MD; Chief Editor: Barry E Brenner, MD, PhD, FACEP more...
No specific laboratory studies are indicated for hip dislocation. Laboratory studies should focus on the overall trauma workup and/or preoperative testing. Type and crossmatching of blood products is generally the most useful.
A portable anteroposterior (AP) pelvis radiograph is often ordered as part of an initial trauma workup. The initial test should be a radiograph of the pelvis and hip. The presence of a hip dislocation can be subtle; however, a careful inspection of the AP pelvis radiograph should reveal most hip dislocations. Lateral views may further classify the type of dislocation.
The position of the femoral head relative to the acetabulum should be symmetrical. The joint space should be examined for bony fragments, widening, or evidence of an effusion.
Both femoral heads should be roughly the same size. In a posterior dislocation, the femoral head may appear smaller than the contralateral side. This is because it is further away from the x-ray beam and is magnified less. The opposite is true of anterior dislocations.
The positions of the trochanters in relation to the femoral shaft may reveal abnormal rotation.
Shenton’s line is a smooth curved line defined by the obturator foramen and the femoral metaphysis. If this line is disrupted, a hip fracture, dislocation, or femoral neck fracture should be suspected.
A thorough inspection of the film for associated fractures must be conducted.
If the AP pelvis film is nondiagnostic and a high index of suspicion exists, a lateral hip film, dedicated hip films, Judet views, or CT scan may be indicated.
The image below is a routine AP pelvis film obtained from a patient who experienced a multiple rollover motor vehicle crash. It demonstrates that sometimes radiographic findings can be more subtle.
A CT is an accurate test for diagnosing hip injuries except in patients with prosthetic hips where streak artifact obscures the image. A CT accurately delineates the type of dislocation as well as any accompanying fractures (as shown in the image below). CT scans of the pelvis are routinely obtained on major trauma patients. The information obtained by CT can be used in the emergency department and for long-term prognosis and management. If a CT scan is being performed to evaluate the abdomen and pelvis, the hip should be examined for pathology. However, a dedicated hip CT scan should not delay reduction. After the hip is reduced, a CT scan of the hip will provide valuable information to the orthopedist for further surgical or conservative management.
In a series of adolescents after posterior hip dislocation, CT identified all bone injuries but underestimated the involvement of posterior wall fractures. However, it was possible to assess posterior wall size and fracture displacement with MRI. All soft-tissue injuries that were confirmed at surgery, including avulsion of the posterior labrum, were identified by MRI preoperatively.
MRI has a limited role in acute diagnosis and delineation of hip dislocations. Patients with multiple trauma are often unstable for MRI. It is time consuming and often unavailable. Once the patient is stabilized and the hip is reduced, MRI can provide valuable information about long-term management and prognosis. An MRI 2-3 months after reduction can verify proper location and to screen for complications, such as avascular necrosis (AVN), osteoarthritis, and heterotopic calcification, at an early stage.
Intra-articular injuries and loose bodies are common in adolescent and young adult patients undergoing arthroscopy following traumatic hip dislocation. In a study of 12 hips in 12 patients (8 males, 4 females; mean age, 16.3 yr; range, 11-25 yr, loose bodies were identified in 6 of 12 patients (50%) on preoperative imaging and in 8 of 12 patients (67%) at arthroscopy. The 2 patients with unidentified loose bodies on imaging did not have a preoperative MRI. In the study, 11 patients had CT scans, 4 had MRI scans, and 3 had both.
Radiographs should be the initial imaging study in patients with suspected AVN.
Radionuclide scanning is a sensitive method for depicting AVN, though MRI, has greater sensitivity and specificity.
Reduction techniques for posterior dislocations are described below.
Allis method [1, 16]
The patient should be supine and under procedural sedation. The combined weight of the patient and physician may exceed the weight limit of the stretcher. It is generally unsafe for the physician to be standing on a stretcher. For these reasons, placing the patient on the floor rather than on the stretcher is often useful.
An assistant should stabilize the pelvis. The physician should initially be toward the patient’s feet, providing in-line traction. The physician should then gently flex the hip 60-90º while maintaining in-line traction. At this point, the physician is standing directly above the patient’s hip, providing traction in-line with the deformity.
Gently adducting the hip can force the head of the femur laterally and help it clear the acetabular rim. Alternately, gentle lateral traction can be applied to the proximal femur.
Reduction can be confirmed by a click that is felt and may be heard as well. The patient should assume normal anatomical position.
Captain Morgan technique 
Another new technique gaining favor is the "Captain Morgan," which is a modification of the technique reported by Lefkowitz. Its name is derived from the resemblance of the position to the pose of the "Captain" on the logo of a popular commercially available rum.
In this technique, the patient is placed in the supine position (with the suggestion that the patient be on a backboard with the pelvic strap retained), with the injured side knee flexed to 90 º. The physician stands on the ipsilateral side facing across the stretcher and places his foot upon the stretcher (or backboard) with his knee under the ipsilateral knee of the patient. He then places one hand behind the knee and the other stabilizes by holding the ipsilateral ankle. Traction force is generated by the physician lifting with his hand behind the knee and by plantar flexing his foot that is under the knee. Rotational and abduction/adduction forces can be applied to facilitate the maneuver if necessary.
Other authors have noted that when using this technique, care must be taken to prevent using the knee as a fulcrum because ligamentous disruption of the knee can result.
East Baltimore lift 
The East Baltimore lift is a newer technique that has been used with good success by some centers. The patient is placed in the supine position, with the physician on the ipsilateral side of injury with an assistant facing him from across the table. The physician gently flexes the leg so that the hip and knee are in approximately 90 º of flexion; then the physician faces his assistant, places one hand on the ankle, and the other arm crosses under the proximal calf to place the hand on the assistant’s shoulder, cradling the flexed knee at the elbow. The pelvis is then braced by the assistant or a second assistant while the physician and first assistant squat slightly, bending at the knees, then upon rising, apply gentle, controlled traction to the femur, with manipulation at the ankle by the physician allowing rotational control of the hip to facilitate reduction.
Stimson method [1, 16]
This method is mechanically the same as the Allis method, but the positioning is opposite. Although some physicians prefer this method because of its technical ease and high success rate, this method has some important disadvantages. It requires the patient to be in a prone position, which may not be possible for the patient with multiple trauma. Monitoring the patient during procedural sedation is also difficult.
The prone patient is placed so the pelvis on the affected side hangs either over the end or over the side of the stretcher. The hip and knee are flexed to 90o. Downward pressure is applied to the popliteal fossa, providing traction in-line with the deformity. An assistant stabilizes the pelvis and trunk preventing the patient from being pulled off the stretcher.
Whistler technique 
The patient is placed supine with ipsilateral knee flexed to 120 º. The physician stands on the affected side and places an arm under the ipsilateral knee with his or her hand resting on the contralateral knee. The pelvis and ankle are stabilized by an assistant or the physician’s free hand. The physician raises his or her arm, which applies an anterior force to the knee and subsequently to the affected hip.
See Joint Reduction, Hip Dislocation, Posterior.
A modified Allis technique may be used. The patient is placed supine. The physician stands at the foot of the stretcher. Traction is applied to a neutral hip while an assistant stabilizes the pelvis. Gentle lateral traction applied to the proximal femur facilitates the femoral head clearing the acetabular rim.
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