Joint Reduction, Elbow Dislocation, Posterior 

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. This injury entails disengagement of the coronoid process of the ulna from the trochlea of the humerus with movement posteriorly.^[2] 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.^[3] 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.^[4] 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, although 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.

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. 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, internal fixation (ORIF); repair/reconstruction of ligaments; and/or dynamic external fixation.^[5] ,^{[6, 7]}

• 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.

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

• Use of intravenous analgesics should be considered. Analgesics may be administered prior to obtaining radiograph.
• Regional anesthesia is established using the following steps:

  • Locate the center of the triangle formed by the lateral olecranon, head of radius, and lateral epicondyle of humerus.^[8]
  • 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 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.

• Aspiration

  • Syringe, 10 mL
  • Needle, 22 gauge
  • Betadine
  • Gauze
• Regional anesthesia

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

  • Stretcher or other stable surface
  • Assistant
• Postreduction posterior long-arm splint

  • Undercast cotton padding
  • Plaster
  • Bandage, 4-inch

• Place patient prone on the stretcher with the affected arm flexed 90 degrees over the edge (see image below). This is the preferred initial approach. Prone position.
• The supine approach may also be attempted.

  • Position the patient supine on the stretcher.
  • The affected arm (humerus) should be in position against the stretcher.
• A sitting approach has also been described.

  • The patient should sit against a chair.
  • The affected arm is draped over the back of the chair.

Prone (one-person) technique

• Position patient prone as described above.
• Correct any medial or lateral translation of the proximal ulna.
• Grab wrist of injured arm. Apply traction and slight supination to 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 image below).Prone (one-person) technique.
• Reduction is achieved after an obvious "clunk" is appreciated.
• Restoration of normal joint contour should be noted.

Prone (two-person) technique

• Position patient prone as described above.
• 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 image below). Prone (two-person) technique, positioning of fingers against posterior olecranon.
• Apply longitudinal traction to the arm with the elbow in slight flexion (see image below).Prone (two-person) technique.
• If reduction is not achieved, flex the elbow or have assistant lift the humerus.
• Reduction is noted by a definite clunk.

Traditional traction (supine approach)

• Position patient supine 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 image below). Supine approach.
• If not successful after 10 minutes, gently flex the forearm or apply traction to the proximal volar surface of the forearm (see image below). Supine approach, adding flexion and pressure against proximal volar surface of forearm.
• Reduction is achieved after hearing or feeling the characteristic clunk.

• Obtain a thorough history and perform a complete physical examination.
• Immediately perform closed reduction if evidence of neurovascular compromise is present. 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.
• Obtain radiographic films in children prior to reduction. Ligaments and tendons in children are stronger than bone, making fractures more common.
• The prone approach allows for more muscular relaxation, and this position should be considered as the initial approach.
• Multiple approaches may be required before successful reduction.
• New or worsening neurovascular compromise postreduction is an important complication. Immediately consult an orthopedist, vascular surgeon, or both.
• Posterior dislocations with associated fractures, also known as complex posterior dislocations, often require open reduction and fixation. These dislocations are often associated with significant ligamentous injury. In some cases, complex posterior elbow dislocations may be managed with closed reduction.
• Delayed vascular compromise is an important complication postreduction. All patients should be observed for a period of approximately 2-3 hours postreduction. 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 such that the elbow is maintained at 90 degrees of flexion and the forearm is positioned neutral to pronation and supination. The metacarpophalangeal joints should be free to flex. For an illustrated demonstration of the application of a posterior long-arm splint, see eMedicine article Splinting, Posterior, Long Arm.

• Brachial artery injury

  • This is the most serious complication.
  • Check for signs of delayed vascular compromise postreduction.
  • If present, loosen splint and decrease degree of flexion.
  • If pulse is not restored, immediately consult a surgeon to determine need for emergent arteriogram, exploration, or both.
• Median or ulnar nerve injury

  • New or increased injury after reduction may indicate entrapment.
  • Immediately consult an orthopedist. Surgical intervention may be required.

Range of motion

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

Posterior long-arm splint

• Flex elbow 90 degrees.
• Place forearm in neutral position with respect to pronation and supination.
• Measure plaster slab from midhumerus to palmar crease.Posterior long-arm splint.
• Wet slab.
• Apply slab to ulnar border.
• Secure with 4-inch bandage, maintaining elbow at 90 degrees, keeping the forearm neutral to pronation and supination, and leaving the metacarpophalangeal joints free to flex.

Neurovascular assessment

Evaluate and document median nerve function, ulnar nerve function, and distal pulses after splint placement.

Postreduction films

Obtain anteroposterior (AP) and lateral films of the elbow to determine alignment and to reveal any associated fractures.

Disposition

• Observe patients for 2-3 hours postreduction, as risk exists for delayed vascular compromise. 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.
• Arrange for an orthopedic follow-up visit for the next day.