Acute elbow dislocation in adults occurs at the ulnohumeral joint. For purpose of terminology, most classifications refer to the position of the ulna relative to the humerus after injury. For example, a posterior dislocation, refers to the ulna and radius sitting posterior to the humerus.
Elbow is a very important part of upper limb function and plays very important role in positioning of the hand for grip and prehension. Various day to activities and rcrecreational and sports activities require a wide range movement at the elbow in both flexion and extension and forearm rotation.
Elbow is relatively a stable joint and is dislocated by sufficient force. Because of their vicinity, neurovascular bundle is quite vulnerable to injury in elbow dislocation.
Classification of Elbow Dislocation
Injury can be classified as
- Posterior elbow dislocation
- Posteromedial elbow dislocation
- Posterolateral ellbow dislocation
- Anterior elbow dislocation
- Medial elbow dislocation
- Lateral elbow dislocation
- Divergent elbow dislcoation
Most acute elbow dislocations are posterior. Anterior, medial, lateral, and divergent forms are very rare.
Mechanism of Injury
Posterior dislocations of the elbow are commonly caused by a fall on the hand or wrist. As force is transmitted from the fall to the extended elbow, a resultant anterior force is generated that levers the ulna out of the trochlea. As the joint continues to hyperextend, the anterior capsule and collateral ligaments are placed under increasing tension and eventually fail.
Anterior dislocation may be caused by impact on the posterior forearm in a slightly flexed position.
Clinical Presentation of Elbow Dislocation
The patient would present with a history of fall on the hand or wrist. There would be history of elbow giving way after that following which the patient was unable to use his elbow. The patient would complaint of extreme pain in the elbow and would support his upper limb to prevent any movement at elbow.
The first priority of care is to assess the neurovascular status of the hand and forearm. Brachial artery and median and ulnar nerves are most vulnerable . Xrays, anteroposterior and lateral views of elbow are studied for associated fractures around the elbow.
Anteroposteriror and lateral views of the elbow are sufficient for diagnosis. In case of a vascular injury appropriate investigations like color doppler and arteriography help to find the injury and plan the treatment.
Treatment of Elbow Dislocation
An uncomplicated pure dislocation of elbow can be easily treated by closed methods. In case of associated fractures, the treatment varies according to fracture pattern. Fracture of the humerus, olecronon, coronoid process or radial head fracture can occur along with dislocation of the elbow.
In case of vascular injury, the repair of the vessel is first priority. However in associated nerve injuries, the treatment of closed reduction and plaster application can be very well initiated and observed.
If the dislocation is open with a large wound over the elbow, surgery is almost always required.
Closed Reduction of Elbow Dislocation
- The patient is placed supine on the table under general anaesthesia or sedation if GA is not available for some reason or other.
- An assistant holds the arm, above the elbow, preferably near shoulder to pull while the physician applies traction in the direction of the deformity.
- A give way sensation is felt.
- Following this, the elbow is flexed to more than ninety degree. If it is not possible to reduce it more than ninety degrees, the fracture has not reduced yet.
- Neurovascular examination is done to rule out any entrapment
- An above elbow slab is applied in hyperflexion i.e. elbow flexed more than ninety degree.
- The position is confirmed in the xrays.
- After two weeks, the elbow is brought to ninety degree of flexion and plaster is continued for another 6 weeks.
Elbow Dislocation with Arterial Injury
Brachial artery can be injured in dislocation of the elbow because of its vicinity. It can occur independently or along with nerve injury.
The injury would, be evident is clinical examination of the affected extremity. The affected limb would be cold or would have lesser temperature as compared to opposite limb. On examination, distal pulses would be absent. However presence o pulses do not rule out vascular injury per se. It is necessary to examine for signs of increased compartment pressure in the forearm and hand. Pain with gentle passive extension of the digits is the most important early indicator of ischemia.
The elbow needs to investigated as that without injury. Loss of pulse does not preclude attempted closed reduction.
After the diagnosis has been made, the elbow should be gently reduced. If the pulse at the wrist does not return after the reduction, patient should be investigated for arterial injury.
Once the lesion has been identified, the patient should be prepared for immediate arterial reconstruction. Arterial repair with saphenous vein grafting is the standard of care. If the zone of injury is quite extensive, and if full mobility after repair is attempted, the reconstructed vessel must have adequate length to permit full extension. Occasionally no graft is needed.
Elbow Dislocations with Nerve Injury
Median, ulnar, radial, and anterior interosseous nerves are vulnerable to injury in elbow dislocationare.
In addition to injury, the nerve can be affected at the time of reduction.
A detailed nerve examination should be done at the first encounter with the patient. Similarly, an examination after the reduction of the dislocation should be done.
If a nerve is injured at the time of injury and does not improve after the reduction, it is best for to wait and watch for recovery. If no sign of recovery is noted till 3 months, an operation should be considered.
In case of open injury, early exploration should be done.
In case the injury to nerve occurs at the time of reduction, exploration is indicated.
Anterior Elbow Dislcoation
Anterior dislocation of elbow is quite rarer as compared to posterior dislocation. It usually occurs after a fall which results in a force striking the posterior forearm in the flexed position.
Because of the mechanism of injury, a fracture of the olecranon commonly occurs with this injury.The arm appears shortened and forearm is in supination. The distal humerus is prominent posteriorly. The biceps tendon tents the skin anteriorly. Because the the dislocation is anterior, injury to nerve and vessel can occur frequently. Therefore, careful assessment for neurovascular injury is mandatory.
The reduction maneuver is the reverse of the posterior dislocation.
Medial and Lateral Elbow Dislocation
Medial and lateral dislocations present with a widening of elbow. However, the relative lengths of the arm and forearm are not changed much.
The patient presents with typical symptoms of pain swelling and the diagnosis should be suspected if mediolateral widening of elbow is present.
Anteroposterior and lateral views are sufficient to make the diagnosis.
In the anteroposterior x-ray, a pure medial or lateral dislocation shows the greater sigmoid notch of the ulna in the plane of the distal humerus
The clinical diagnosis can be difficult in some cases especially in some patients of lateral dislocations with considerable swelling.
as with other orthopaedic injuries, neuarl and vascular examination must be done to rule out the injury to these structres.
The treatment of pure medial and lateral elbow dislocation is closed reduction followed by splintage in reduced position for the required period. In case of associated fractures or failure of closed reduction, surgery might be needed.
Divergent of the Elbow Dislocation
Divergent dislocation of the elbow is another rare type of dislocation. In this the radius and ulna dislocate in diverging directions.
There are two types of this dislocation
- Mediolateral or transverse.
Anteroposterior type is more common. It this, a posterior dislocation of the ulna occurs resulting in lodging of coronoid process in the olecranon fossa. The radial head is lies anteriorly in the region of the coronoid fossa.
This kind of injury occurs when the forearm is in forced pronation and the humerus is forced distally, separating the radius and ulna.
This injury causes massive soft tissue trauma and along with ligaments of elbow, the interosseous membrane is torn.
Examination and investigations are done in usual manner.
Reduction technique is similar to that of a posterior dislocation.
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