Best Practices: Effective Reduction Techniques for Lower Extremity Dislocations

Dislocations, such as the medial ankle subtalar dislocation (shown), are common orthopaedic injuries in which traumatic forces disrupt joint articulations. Fractures often accompany dislocations; radiography is usually required to distinguish between the two. Technically, dislocation refers to a complete discontinuity between articular surfaces; partial discontinuities are termed subluxations. Classification of dislocations is based on the position of the distal bone relative to the proximal bone. Manual closed reduction of a dislocated joint can avoid and sometimes reverse neurovascular injury. Manual reduction also relieves pain and discomfort far more effectively and quickly than analgesics.

Ankle dislocations are classified according to the relationship between the talus/foot and tibia (shown). The position of the dislocated talus may be lateral (left image), posterior, medial, anterior, upward, or posteromedial to the distal tibia. Subtalar dislocations of the foot can also occur (right image).

Posterior dislocation of the talus with respect to the tibia (red arrows) is the most common type of ankle dislocation. Dislocation may be associated with a distal fibula fracture (blue arrow). Pure ankle dislocations must be distinguished from subtalar (foot) dislocations because reduction techniques for the two differ. Neurovascular compromise is an indication for immediate reduction without waiting for radiographs. However, clinicians should be aware that attempts to reduce a subtalar dislocation using the ankle reduction technique will be unsuccessful and may further damage the articular cartilage. Image courtesy of Wikimedia Commons.

This image shows an unstable bimalleolar fracture and right ankle dislocation on anteroposterior plain radiograph. Both the end of the fibula (1) and the tibia (2) are broken. The malleolar fragments—the medial malleolus (yellow arrow) and lateral malleolus (white arrowhead)—are displaced. Image courtesy of Wikimedia Commons.

Closed ankle reduction, such as the technique for posterior ankle dislocation (shown), requires good patient positioning so that the operator and an assistant can apply appropriate traction and countertraction. Typically, the patient is supine with the ipsilateral leg flexed at the hip and knee. Slight rotation of the patient to the ipsilateral side facilitates countertraction at the proximal tibia by the assistant. The operator then holds the foot in plantar flexion and applies gentle axial traction.

For a posterior dislocation (shown), axial traction and anterior pressure are applied. Continue to apply gentle axial traction, along with pressure, in the direction opposite of the direction of the dislocation. Successful reduction is indicated by restoration of the normal surface anatomy. Rapid improvement in pain is also noted and neurovascular deficits may improve quickly. With all reductions, postreduction radiographs are required to confirm reduction and assess further for fracture.

This image shows a traumatic Lisfranc fracture with fractures of the second, third, and fourth metatarsals (yellow arrow). All dislocations in the foot (with the exception of simple dislocations of the toes) are uncommon injuries. The most common of these injuries is a dislocation that involves the tarsometatarsal joints (blue arrow), which is referred to as a Lisfranc injury. Lisfranc injuries typically require operative reduction and fixation. Image courtesy of Wikimedia Commons.

In this anteroposterior radiograph of a Lisfranc dislocation, note the disruption of the normal second tarsometatarsal alignment (blue arrow). Postoperative anteroposterior radiograph demonstrates reduction and fixation of Lisfranc dislocation (right image).^[1]

In this lateral radiograph of a typical Lisfranc injury, note the malalignment of the metatarsal bases with the midfoot (red arrows).

This preoperative lateral radiograph demonstrates loss of plantar integrity through the Lisfranc joint area (red arrows). The normal linear alignment of the bones from the metatarsals to the talus is lost, with a sag at the tarsometatarsal joint (top image). Postoperative lateral radiograph demonstrates restoration of alignment with tarsometatarsal fusion (bottom image).^[1]

Patellar subluxations (shown) and dislocations commonly occur in athletes who participate in sports in which planting of the foot and ankle is followed by sudden twisting at the knee, such as in soccer and basketball. The reported incidence is 5.8 per 100,000 persons, increasing to 29 per 100,000 in the 10- to 17-year age group.^[2] Females may be more prone to this condition. Lateral dislocations are most common. Fortunately, many patellar subluxations self-reduce, and dislocation reduction is often straightforward.

For patellar dislocation reduction (shown), the patient is positioned with the knee slightly flexed, either sitting with legs dangling off the gurney or lying supine with pillows supporting the knee. The operator stands on the side of the dislocation (eg, to the right of the patient for a right lateral dislocation). The operator grasps the distal tibia with one hand to extend the knee. The other hand is used to apply pressure slightly upward and away from the operator (yellow arrow), lifting the patella over the femoral condyle and into place.

True knee dislocation (shown) describes a disarticulation between the distal femur and the tibial plateau. Knee dislocations are relatively uncommon, requiring high-energy trauma to produce true dislocation with potential disruption of the multiple ligaments, blood vessels, and nerves. Marked obesity is associated with low-impact knee dislocation. Vascular injury is common after knee dislocation, and compartment syndrome may develop as a result of ischemic muscle injury.

Knee dislocations are commonly classified according to the displacement of the tibia relative to the femur: medial, lateral, rotatory, posterior, or anterior (shown). Anterior dislocation is the most common type, followed by posterior dislocation. An anatomic classification developed by Schenck and modified by Wagner categorizes knee dislocations according to ligament and vascular involvement. This classification cannot be made clinically and is determined at the time of surgery.

Despite the clinical severity of knee dislocation, reduction is straightforward: With the patient supine, countertraction is applied at the proximal femur and hip by one or more assistants; the operator grasps the tibia with both hands and applies firm, longitudinal traction (shown). Because of the risk for popliteal artery and peroneal nerve injury, all patients should be admitted for serial neurovascular checks after knee dislocation. An ankle-brachial index less than 0.90 has been found to be specific and sensitive for popliteal artery injury after knee dislocation.

This image shows a lateral knee dislocation before reduction. Medial, lateral, and rotatory dislocations require varus, valgus, or rotatory components of applied force. Reduction should not be delayed in limbs with obvious vascular impairment. Only patients with good peripheral pulses should undergo prereduction radiography.^[3]

This image shows a lateral knee dislocation after reduction. After reduction, splint the lower extremity in approximately 20 degrees of flexion to avoid postreduction re-dislocation, apply ice, and keep the knee elevated. Postreduction hard signs of arterial injury should prompt emergent vascular surgical intervention that should not be delayed for arteriography.^[3] Arteriography may be performed intraoperatively.

Motor vehicle collisions cause two thirds of traumatic hip dislocations, as in this posterior fracture-dislocation of the right hip. The bony fragments are likely part of the acetabulum (arrow). Hip dislocation nomenclature is based on the relationship of the femoral head to the acetabulum—anterior, posterior, or central (with consequent acetabular fracture). Most traumatic hip dislocations caused by motor vehicle collisions are posterior dislocations due to the force of the dashboard pushing axially along the femur in a seated driver or passenger; less frequently, central dislocations occur with side-impact collisions.

Hip prostheses (shown) dislocate easily after low-energy trauma. Some patients experience recurrent prosthetic hip dislocations from movements as simple as transitioning to a standing position from a low, seated position with the buttocks initially positioned lower than the knees. Image courtesy of Wikimedia Commons.

Hip dislocations are classified as congenital or traumatic, as in this right posterior hip dislocation (arrow) in a young woman following a high-speed motor vehicle collision. With an incidence of approximately 2-4 per 1000 births, congenital hip dislocations overwhelmingly affect girls (80%-85% of cases) and are usually due to dysplasia of the femoral head or acetabulum. Outside the neonatal period, hip dislocations are caused by high-energy trauma and are often associated with traumatic injuries to other areas of the body. Sciatic nerve injury is the most common acute complication. A neurovascular examination should be documented before and after reduction. Prompt reduction is indicated.

This CT scan reveals a posterior dislocation of the right hip (red arrow) with acetabular fracture.

In the Allis technique for reduction of posterior hip dislocation (shown), an assistant stabilizes the pelvis while the patient lies supine. The operator applies inline traction on the ipsilateral leg, then flexes the hip 60-90 degrees. Lateral traction along the proximal femur, with or without adduction and internal rotation at the hip joint, should bring the femoral head over the acetabular rim. Because positioning for hip reduction techniques may require the surface to sustain the weight of both patient and operator, placing the patient on the floor is an option.

In the Stimson technique (shown), the patient is placed in a prone position with the pelvis hanging over the edge of the stretcher. While an assistant holds the patient steady, the knee and hip are flexed to 90 degrees while downward axial pressure is applied along the femur.

In the Whistler technique (shown), the operator uses one arm as a fulcrum to lever the patient's knee forward. The patient is placed supine with both knees bent. While an assistant steadies the patient's pelvis, the operator stands on the ipsilateral side and places the arm closer to the patient's hip under the patient's ipsilateral knee, with the hand grasping the contralateral knee. The patient's popliteal fossa rests on the operator's forearm, creating a fulcrum (black arrow). The operator then uses the other hand to push down the ankle (yellow arrow), flexing the knee and causing longitudinal traction along the femur (red arrow).

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For more information, see the following resources:

• Medscape Reference: Ankle Dislocation in Emergency Medicine
• Medscape Reference: Hip Dislocation in Emergency Medicine
• Medscape Reference: Knee Dislocation in Emergency Medicine
• Medscape Reference: Lisfranc Fracture Dislocation
• Medscape Reference: Patellar Injury and Dislocation

Contributor Information

Authors

Melisa W. Lai Becker, MD
Instructor, Harvard Medical School
Director, Division of Medical Toxicology
Attending Physician, Department of Emergency Medicine
Cambridge Hospital
Cambridge, Massachusetts

Disclosure: Melisa W. Lai Becker, MD, has disclosed no relevant financial relationships.

Mark P. Brady, PA-C
Chief Physician Assistant
Department of Emergency Medicine
Cambridge Hospital
Cambridge Health Alliance
Cambridge, Massachusetts

Disclosure: Mark P. Brady, PA-C, has disclosed no relevant financial relationships.

Contributor Information

Editor

Lars Grimm, MD, MHS
House Staff
Department of Diagnostic Radiology
Duke University Medical Center
Durham, North Carolina

Disclosure: Lars Grimm, MD, MHS, has disclosed no relevant financial relationships.

Reviewer
Richard S. Krause, MD
Senior Faculty
Department of Emergency Medicine
State University of New York at Buffalo School of Medicine
Buffalo, New York

Disclosure: Richard S. Krause, MD, has disclosed no relevant financial relationships.