Reduction of Posterior Elbow Dislocation 

Updated: Oct 12, 2018
Author: Nina Chicharoen, MD, MPH; Chief Editor: Erik D Schraga, MD 

Overview

Background

In adults, the elbow is the second most frequently dislocated major joint, after the shoulder. It is the most commonly dislocated joint in children.[1]  More than 90% of all elbow dislocations are posterior dislocations.[2] This injury entails disengagement of the coronoid process of the ulna from the trochlea of the humerus with movement posteriorly.[3]  The mechanism of injury is typically a fall onto an outstretched hand (FOOSH) with the elbow in extension upon impact.

The patient typically presents with a shortened forearm that is held in flexion with a prominent olecranon posteriorly. Noting disruption of the tight triangular relationship of the tip of the olecranon with the distal humeral epicondyles, when comparing the injured elbow with the unaffected side, can help to confirm the diagnosis clinically.

Injured structures include the anterior and posterior bands of the medial and lateral collateral ligaments of the elbow, along with, at times, the brachialis muscle, the flexor-pronator muscle group, and articular cartilage.[4]  The ipsilateral upper extremity should be examined for other injuries as well, particularly shoulder and wrist fractures and disruption of the distal radioulnar joint. The elbow should be inspected for crepitus, which is an indicator of fracture.

Of note, the ulnar nerve, median nerve, and brachial artery can be compromised.[5]  Therefore, assessing distal neurovascular status is crucial to determine the need for immediate reduction. Injury to the median and ulnar nerves is typically the result of stretch, entrapment, or severance. Brachial artery injury, though possible in any type of dislocation, is frequently seen in open dislocations. Vascular compromise can be caused by brachial artery injury or compression and may be delayed in presentation as a result of hematoma formation or soft-tissue swelling. Therefore, vascular integrity warrants careful monitoring even after successful reduction.

Indications

Joint reduction is indicated for any clinical or radiographic diagnosis of acute posterior elbow dislocation. Urgent joint reduction is indicated if evidence of neurovascular compromise is present.

Contraindications

Contraindications for joint reduction in the setting of a posterior elbow dislocation include the following:

  • Lack of familiarity with reduction
  • Injury without neurovascular compromise in any child prior to radiographic evaluation; fractures are more common than dislocations in children
  • Multiple prior unsuccessful attempts at reduction
 

Periprocedural Care

Preprocedural Planning

Obtain a thorough history, and perform a complete physical examination. Evidence of neurovascular compromise is an indication for immediate closed reduction. In general, a clinical diagnosis of posterior elbow dislocation is sufficient, especially in adults. Achieving early reduction is often easier, given the presence of minimal muscle spasm and swelling.

Plain films of the elbow in the anteroposterior (AP) and lateral projections should be obtained to confirm the diagnosis and to determine the presence of fractures. Fractures of the distal humerus, radial head, and coronoid process occur commonly with this injury. It is particularly useful to obtain radiographic films in children before reduction: Ligaments and tendons in children are stronger than bone, making fractures more common. In children younger than 14 years, medial epicondyle separation is typically seen.

Orthopedic consultation should be considered. Simple posterior elbow dislocations are treated with closed reduction. Complex posterior elbow dislocations (ie, those with associated fractures) require closed reduction; open reduction with internal fixation (ORIF); repair/reconstruction of ligaments; and/or dynamic external fixation.[6, 7, 8]

Equipment

Materials required for aspiration include the following:

  • Syringe, 10 mL
  • Needle, 22 gauge
  • Povidone-iodine
  • Gauze

Materials required for regional anesthesia include the following:

  • Lidocaine 2% without epinephrine
  • Syringe, 10 mL
  • Needle, 22 gauge
  • Povidone-iodine
  • Gauze

Materials required for reduction include the following:

  • Stretcher or other stable surface
  • Assistant

Materials required for postreduction posterior long arm splinting include the following:

  • Undercast cotton padding
  • Plaster
  • Bandage, 4 in. (10 cm)

Patient Preparation

Anesthesia

Use of intravenous analgesics should be considered. Analgesics may be administered before radiography.

Regional anesthesia is established via the following steps:

  • Locate the center of the triangle formed by the lateral olecranon, the head of the radius, and the lateral epicondyle of the humerus [9]
  • Sterilely prepare and drape the area
  • Insert the needle into the soft tissue within the triangle, directing it toward the opposite (medial) epicondyle
  • Aspirate to remove blood in the joint
  • Inject, in the same location and direction, 3-5 mL of lidocaine 2% without epinephrine
  • Gently move the joint through its full range of motion to determine that pain relief has been achieved

General anesthesia is generally not necessary for closed reduction of uncomplicated posterior elbow dislocations. Procedural sedation is rarely needed in adults but may be preferred for use in children.

Positioning

The preferred approach to positioning is to place the patient prone on the stretcher with the affected arm flexed 90º over the edge (see the image below).

Reduction of posterior elbow dislocation. Prone po Reduction of posterior elbow dislocation. Prone positioning.

An alternative approach is to place the patient supine on the stretcher with the affected arm (humerus) in position against the stretcher. As another alternative, the patient may sit against a chair with the affected arm draped over the back of the chair.

 

Technique

Approach Considerations

Reduction of the posterior elbow dislocation may be accomplished by means of either a prone or a supine approach.[10] The prone approach allows for more muscular relaxation, and this position should be considered as the initial approach. Multiple approaches may be required before reduction is successfully accomplished.

Posterior dislocations with associated fractures, also known as complex posterior dislocations, often require open reduction and internal fixation (ORIF). These dislocations are often associated with significant ligamentous injury. In some cases, complex posterior elbow dislocations may be managed with closed reduction.

Posterior elbow dislocations that are neglected, as is not uncommon in developing countries, can often be effectively treated with open reduction.[11]

Delayed vascular compromise is an important complication after reduction. All patients should be observed for a period of approximately 2-3 hours after reduction. If no evidence of vascular compromise arises, patients can be sent home with appropriate follow-up and instructions to watch for further problems.

A posterior long arm splint should be applied to the ulnar surface of the successfully reduced arm. The splint should also be secured so that the elbow is maintained at 90º of flexion and the forearm is positioned neutral to pronation and supination. The metacarpophalangeal (MCP) joints should be free to flex. For an illustrated demonstration of the application of a posterior long arm splint, see Posterior Long Arm Splinting.

Prone Approach

One person

Place the patient in the prone position. Correct any medial or lateral translation of the proximal ulna. Grab the wrist of the injured arm. Apply traction and slight supination to the forearm. Attempt to distract and unlock the coronoid process from the olecranon fossa.

Using the other hand, apply pressure to the posterior aspect of the olecranon while the arm is pronated (see the image below). Reduction is achieved after an obvious "clunk" is appreciated. Restoration of normal joint contour should be noted

Reduction of posterior elbow dislocation. Prone (o Reduction of posterior elbow dislocation. Prone (one-person) technique.

Two persons

Place the patient in the prone position. Have an assistant, with his or her back toward the patient, encircle the humerus with both hands and apply pressure with the thumbs to the posterior aspect of the olecranon (see the image below).

Reduction of posterior elbow dislocation. Prone (t Reduction of posterior elbow dislocation. Prone (two-person) technique. Positioning of fingers against posterior olecranon.

Apply longitudinal traction to the arm with the elbow in slight flexion (see the image below). If reduction is not achieved, flex the elbow or have assistant lift the humerus. Reduction is signaled by a definite clunk.

Reduction of posterior elbow dislocation. Prone (t Reduction of posterior elbow dislocation. Prone (two-person) technique.

Supine Approach

Place the patient in the supine position on the stretcher. Have an assistant stabilize the humerus against the stretcher with both hands. Grasp the wrist, and apply slow, steady, inline traction, keeping the elbow slightly flexed and the wrist supinated (see the image below).

Reduction of posterior elbow dislocation. Supine a Reduction of posterior elbow dislocation. Supine approach.

If success has not been achieved after 10 minutes, gently flex the forearm or apply traction to the proximal volar surface of the forearm (see the image below). Reduction is confirmed by hearing or feeling the characteristic clunk.

Reduction of posterior elbow dislocation. Supine a Reduction of posterior elbow dislocation. Supine approach, with addition of flexion and pressure against proximal volar surface of forearm.

Postprocedural Care

Assess the stability of the elbow by gently moving the joint through its full range of motion, watching especially for instability upon elbow extension.

To apply a posterior long arm splint, flex the elbow 90º. Place the forearm in neutral position with respect to pronation and supination. Measure a plaster slab from the midhumerus to the palmar crease (see the image below). Wet the slab, and apply it to the ulnar border. Secure the slab with a 4-in. bandage, maintaining the elbow at 90º, keeping the forearm neutral to pronation and supination, and leaving the MCP joints free to flex.

Posterior long arm splint. Posterior long arm splint.

Neurovascular assessment is indicated, including evaluation and documentation of median nerve function, ulnar nerve function, and distal pulses. after splint placement.

Anteroposterior (AP) and lateral films of the elbow should be obtained to determine alignment and to reveal any associated fractures.

Because of the risk of delayed vascular compromise, patients should be observed for 2-3 hours after reduction. Some clinicians may opt to admit patients for such observation. Patients then can be discharged with adequate analgesia and instructions to ice and elevate the injury and to watch for signs of vascular compromise. An orthopedic follow-up visit should be arranged for the following day.

Complications

The most serious complication of joint reduction for posterior elbow dislocation is brachial artery injury.[12, 13] Check for signs of delayed vascular compromise after reduction. If compromise is present, loosen the splint and decrease the degree of flexion. If pulse is not restored, immediately consult a surgeon to determine the need for emergency arteriography, exploration, or both.

Median or ulnar nerve injury may also occur.[14, 15]  New or increased injury after reduction may indicate entrapment. Immediately consult an orthopedist. Surgical intervention may be required.

Chronically unreduced posterior elbow dislocations have been observed to be associated with posttraumatic contracture of the elbow, periarticular ossifications, and loosening of the radial head endoprosthesis.[16]