ANATOMY OF THE ELBOW JOINT
The bones of the forearm, the radius and ulna, articulate with the lower end of the humerus at the elbow. This is a hinged synovial joint which has a natural stability. Only flexion and extension of the elbow joint are possible, movement occurring about a transverse axis. Supination and pronation of the forearm are obtained through the superior radio-ulnar joint which is a type of ball and socket joint acting with the inferior radio-ulnar joint. The shafts of the forearm bones are connected by fibrous interosseous bands, the radius moving on the ulna around a vertical axis .
Ligaments 1. The lateral ligament is attached, above, to the lower part of the lateral epicondyle of the humerus and below, to the annular ligament. 2. The medial ligament is due to thickening of the capsule that completely invests the joint. It passes from the front of the medial epicondyle of the humerus to the medial edge of the coronoid process of the ulna. 3. The posterior ligament is due to capsular thickening. 4. The annular ligament of the superior radio-ulnar joint receives strong bands from both the lateral ligament and the anterior ligament. It encircles the head of the radius and retains it in contact with the radial notch on the ulna. In this way movement between these two bones is permitted at the joint.
Posteriorly are the triceps tendon and the anconeus tendon which lie to the outer side of the olecranon. They are extensors of the joint. The superficial flexor group of muscles and the pronator radii teres lie to the medial side. To the lateral side lie the superficial extensor group of muscles. They are weak supinators of the forearm but strong extensors of the wrist and fingers. Anteriorly are the brachialis muscle, which is attached to the coronoid process of the ulna, and the biceps tendon which is attached to the bicipital tuberosity of the radius where there is a bursa. These muscles are strong flexors of the joint.
SPECIFIC SPORTS INJURIES TO THE ELBOW Tennis elbow
This injury can occur in golf and fishing as well as in racket sports. The condition affects the extensor muscle origin from the lateral side of the elbow joint. It follows a minor strain in energetic use of the forearm from pronation to supination. The patient complains of pain which spreads from the lateral epicondyle of the humerus often to the forearm muscle. It is brought on by overuse of the extensor and supinator muscles of the forearm and is relieved by rest.
On examination there is tenderness over the lateral epicondyle of the humerus at the site of the extensor muscle origin of the forearm muscles or along the lateral ligament. The pain is brought on by supinating the forearm against resistance. X-rays are usually normal but in long standing cases there may be some calcification in the tissues around the extensor origin.
TREATMENT 1. Rest in the early stage and a short cock-up splint will help. 2. An injection of hydrocortisone and local anaesthetic into the painful area is given. The injection may have to be repeated. 3. Physiotherapy with ultrasound may help. 4. Resting of the arm in a plaster of Paris cast. 5. Manipulation of the elbow under a general anaesthetic, forcing the elbow into full extension with the forearm pronated and the wrist fully flexed. 6. Operative treatment: (a) Lengthening of the extensor carpi radialis brevis. (b) Freeing the extensor origin from the lateral epicondyle of the humerus may be required in stubborn cases. (c) Excision of the thickening discoid fibro-cartilage from the joint and the synovial membrane may be required.
This condition affects the flexor tendon origin from the medial epicondyle of the humerus and becomes chronic with scar tissue formation. Signs and symp- toms are the reverse of a tennis elbow with pain on extending the wrist with the arm in full supination. The left arm is the one usually affected in right-handed golfers, but the injury can occur in other sports.
This is as for a tennis elbow, by rest and physiotherapy. An injection of hydrocortisone and local anaesthetic is helpful. Manipulation in a reverse manner to that of a tennis elbow may be required under a general anaesthetic.
In this condition there is a whiplash injury of the elbow when hyperextension causes the olecranon to come in contact with the olecranon process in the lower humerus. This may cause a fracture or an epiphysitis. This injury is seen in baseball, cricket, as well as field events.
In the early stage, treatment is rest from throwing. It may need a plaster of Paris cast for three to four weeks.
Occasionally excision of bony fragments may be required.
Javelin thrower’s elbow
This is a strain of the medial ligament of the elbow caused by a round arm type of throw. Treatment is to rest the arm and correct the throwing fault by coaching the athlete to lead with the elbow. Physiotherapy and a hydrocortisone injection may be required.
Dislocation of the elbow
This results from a fall on the outstretched hand causing the lower end of the humerus to pass forwards over the coronoid process of the ulna and the head of the radius. This tears the brachialis muscle and joint capsule producing a posterior dislocation. An anterior dislocation occurs in a similar fashion. X-rays are used to confirm the dislocation.
Under a general anaesthetic the dislocation is reduced and the position checked by x-ray. The arm is immobilised in a collar and cuff sling for three to four weeks.
COMPLICATIONS These include: 1. Calcification in the brachialis muscle. This is suspected when the range of movements stop increasing. 2. The medial epicondyle may be trapped in the joint after reduction and must be looked for on an x-ray check. 3. There may be damage to the median and ulnar nerves. ‘Pulled elbow’
In this condition the head of the radius is pulled out of the annular ligament and is likely to occur in sports such as judo.
On examination there is pain and tenderness over the head of the radius. Movements of supination and pronation of the forearm are limited.
The elbow is flexed to a right angle and the extended wrist is grasped. Then, pushing in the long axis of the forearm, the forearm is alternately supinated and pro-nated until the head of the radius clicks back.
FRACTURES OF THE ELBOW
Fractures of the olecranon
These are of two types: 1. Direct injury which results from a fall on the point of the elbow especially on a hard playing surface. The olecranon may be comminuted by the force of the fall or the fracture may be a transverse type with subluxa tion due to the pull of the triceps. 2. Indirect injury which may occur in throwing events due to the vigorous action of the triceps tendon on its insertion. This leads to pain on extending the elbow and is felt over the olecranon. This pain may have a sudden onset or may increase gradually over a week or so. On examination there is pain and tender ness over the olecranon. X-rays confirm the fracture.
If there is displacement, the fracture must be reduced and fixed internally using a screw or tension wire banding. The arm is immobilised in a sling until the wound is healed; then gentle exercises are commenced. Full activity can be resumed when the fracture is radio-logically united.
Fracture of the lateral epicondyle of the humerus
This occurs from a sudden contracture of the extensor muscles of the forearm and is an avulsion fracture. There is pain and tenderness over the lateral epicondyle of the humerus with swelling later. There is pain on extension of the wrist against resistance. X-rays show the fracture which may be displaced.
If the fracture is undisplaced, immobilisation in a collar and cuff sling for three to four weeks until the pain has subsided is all that is required. If the fragment is displaced it must be reduced and is then sutured with strong catgut or fixed with small ‘K’ wires. Activities are resumed when the fracture has united and the wires are removed.
Fracture of the medial epicondyle of the humerus
This is caused by a valgus strain of the elbow with the contraction of the flexor muscles of the forearm. It may also occur as a complication of a dislocation of the elbow. The fragment may remain in the joint after the elbow has been reduced.
There is pain and tenderness over the medial epicondyle of the humerus and pain when the wrist is flexed against resistance. The fracture and the position of the fragment is confirmed by x-rays.
If there is medial displacement, immobilisation in a collar and cuff sling for three weeks is required followed by a gradual increase in exercises. Full activity may be resumed when there is no longer any pain or tenderness.
Fracture of the capitulum of the humerus
This is caused by a fall on the outstretched hand. The head of the radius (which may also be damaged) causes the capitulum to fracture.
There is pain and swelling about the elbow with tenderness over the head of the radius. X-rays confirm the fracture.
If there is no displacement the arm is immobilised in a collar and cuff sling for three or four weeks. If there is displacement of the capitulum, it should be replaced. The head of the radius will help to keep the capitulum in position but if unstable the fragment may be sutured into place with catgut or held in position with ‘K’ wires. Sometimes reduction is not possible because of comminution and then the fragment must be excised.
Fracture of the coronoid process of the olecranon
This may occur after falling on the outstretched arm and is probably associated with a transient dislocation of the elbow.
There is pain, swelling and stiffness in the elbow. The fracture which is rarely displaced is confirmed by x-rays.
Immobilisation in a collar and cuff sling for three to four weeks followed by gradual increase in exercises is required.
Fracture of the head of the radius
This fracture is caused by falling on the outstretched hand, the head of the radius being driven against the capitulum.
There is pain and tenderness over the head of the radius with loss of supination and pronation of the forearm as well as loss of some flexion and extension. Diagnosis is confirmed by x-rays.
If there is a crack fracture with minimal displacement of the fragment, a collar and cuff sling is applied for three weeks followed by exercises to encourage supination and pronation as soon as pain permits. When there is displacement of the fracture with comminution the head of the radius must be excised. Care is taken to ensure that all the fragments are removed. Failure to remove the head of the radius in these fractures will limit supination and pronation of the forearm. The patient can return to full activities in about six to eight weeks after the operation which should be carried out as soon as convenient after the injury.
Supracondylar fractures of the humerus
There are two types of supracondylar fracture of the humerus. 1. The most common is an extension type of injury when the elbow with the lower fragment of the humerus is driven backwards on the humerus. 2. The less common type is a flexion injury with the proximal end of the lower humerus being driven below and behind the lower humeral fragment and elbow joint.
The elbow swells quickly on injury, but immediately after the injury the bony parts can be palpated in the fractured area. It is noted that the triangle formed by the medial and lateral epicondyle of the humerus and the point of the olecranon remains an equilateral triangle. This equilateral triangle is disrupted in a dislocation of the elbow joint. There is pressure upon (or a rupture in some rare cases) the brachial artery which leads to loss of blood supply to the forearm, especially to the flexor muscles. This may lead to Volkmann’s ischaemia if the fracture is not reduced quickly.
Volkmann’s ischaemia occurs when the blood supply to the flexor muscles of the forearm is diminished by spasm of the brachial artery due to irritation of this blood vessel by the fractured humerus. It is recognised by flexion of the fingers with pain in the forearm and pain when the flexed fingers are passively extended. The radial pulse at the wrist is weak and the hand and fingers are swollen and discoloured. There may also be damage to the medial or ulnar nerves at the time of the fracture due to their close approximation to the elbow joint.
Myositis ossificans affecting the brachials muscle may occur causing stiffness of the elbow. This stiffness may be severe and persist, causing contracture of the fingers and wrist.
Urgent reduction of the fracture to avoid a vascular catastrophe is required. It is usually carried out under general anaesthetic. Following reduction the arm is immobilised in a collar and cuff sling for about four to six weeks, when exercises are begun. Open reduction may be required if there is any difficulty in obtaining reduction of the fracture or if there is impairment of the circulation after closed manipulation of the fracture.
The muscles surrounding the elbow joint are strong when acting together and with the natural stability of the hinged joint make an extremely stable articulation. The problem after injury is one of stiffness and this is due to a relative shortening of the ligaments due either to oedema or direct injury. This stiffness may cause great disability to the sportsman if it persists. When there is pain, or in the early stages of an injury, passive movements must not be encouraged. Rest in the early stages leads to absorption of the oedema and repair of the damaged ligament. This period of rest is followed by gentle active movements as soon as the pain and swelling have subsided. The exercises are gradually increased until a full range of movements has been obtained. Vigorous exercises may well lead to stiffening of the joint rather than increasing the range of movements. Accurate reduction of fractures involving the joint surfaces is essential to obtain a full range of movements after an injury. Failure to obtain this by manipulative treatment necessitates internal fixation of the fragments.