Elbow Instability

a. Dislocation

What is an Elbow Dislocation?
An elbow dislocation occurs when the humerus, or arm bone, is dislodged from its notch in the ulna, a forearm bone.

What causes an Elbow Dislocation?
Elbow dislocations generally result from trauma such as falls or motor vehicle accidents. They can also be seen in contact sports, such as football and wrestling. Associated fractures and ligament tears are common.

What are the symptoms?
The patient will feel a ‘pop’, followed by immediate pain and loss of use of the arm. Numbness and tingling may be present in the hand. A visible elbow deformity is present in thin patients.

How is an Elbow dislocation diagnosed?
Dislocations are diagnosed clinically. X-rays are obtained to look for fractures which may have occurred at the time of the dislocation.

How is it treated?
The surgeon will put the elbow back into place using gentle pressure on the tip of the ulna. Associated fractures are then addressed. Ligament tears occurring as a result of the dislocation are usually treated non-operatively unless the elbow remains unstable after reduction.

b. Ulnar Nerve Subluxation

What is an Ulnar Nerve Subluxation?
The ulnar nerve supplies sensation to the hand and controls muscles in the forearm and hand. It passes through a groove in the humerus on the inside of the elbow and sits just under the skin. In this groove, it is commonly referred to as the ‘funny bone’, because striking the ulnar nerve with an object will result in numbness and tingling in the hand. An ulnar nerve subluxation occurs when the nerve is pulled out of its groove with motion of the elbow.

What causes Ulnar Nerve Subluxation?
Elbow motion, combined with lax or absent soft tissue attachments, can lead to subluxation.

What are the symptoms?
The patient may develop pain and numbness and tingling in the forearm, small and ring fingers. A click may be felt as the nerve leaves its groove.

How is Ulnar Nerve Subluxation diagnosed?
Your surgeon will diagnose this on physical exam.

How is it treated?

Patients with few symptoms can be treated with observation, therapy or anti-inflammatory medication.

For severe cases, an incision is created over the nerve, and the nerve is moved anteriorly in the forearm to relieve pain and eliminate subluxations.

c. Lateral Ulnar Collateral Ligament Ruptures (Posterolateral rotatory instability)

What is a Lateral Ulnar Collateral Ligament (LUCL) Rupture?
The lateral ulnar collateral ligament connects the ulna, a bone in the forearm, to the humerus or arm bone. Tears of this ligament are the leading cause of chronic elbow instability.

What causes a LUCL Tear?
Falls on an outstretched hand and elbow dislocations are common causes of LUCL tears. Other causes include fractures, genetically loose connective tissue, long term use of crutches, and injury during surgical procedures.

What are the symptoms?
Patients will describe pain and clicking, snapping, or locking of the elbow as the arm is straightened with the palm facing up.

How is a LUCL tear diagnosed?
Physical exam is the key to diagnosis. The surgeon will position the elbow above the patient’s head and perform a maneuver designed to test the integrity of the ligament. If the elbow joint is felt to separate, or the patient’s pain is reproduced then instability is present. X-rays are usually normal, but may show partial dislocation of the elbow in severe cases.

How is it treated?

Physical therapy to strengthen the muscles that support the elbow may be effective in low demand patients.

Reconstruction of the ligament is recommended using a graft taken from elsewhere in the arm. For acute tears, repair of the ligament, combined with a hinged external fixator may be used to hold the palm of the hand down, while allowing motion at the elbow joint.

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