Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

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Dislocation of the Shoulder Joint

Dislocation of the shoulder joint is a relatively common injury in sports such as ice hockey, team handball, American football, rugby, riding, alpine skiing, skating, and wrestling. Shoulder dislocations are 3 times more common in men 20–30 years old, than in persons aged over 30 years. The male to female ratio for primary dislocation is 9:1.

Injury mechanism

When falling, it is instinctive to lift the arm and turn it outwards to protect the body. Dislocation can occur when the arm, held in this position, receives the impact of the fall. The joint can also be dislocated by falling directly on the lateral aspect of the shoulder or by a violent collision with another player. This injury can also occur when the arm is caught by another player and pulled vigorously outwards and backwards.

Types of dislocation

Anterior dislocation (diverted forward and downward) is most common and has a tendency to recur in young, active people.

–Posterior dislocation (backward) is unusual; the injury is commonly missed, and needs special attention. It can be difficult to diagnose and treat.

Pathology

Complete dislocations of the shoulder are characterized by lesions of the labrum, capsule, muscles, and/or bone. The labrum can be avulsed from the rim; this is called theBankart lesion and is the most common cause of recurrent dislocation.

A dislocation of the shoulder may include varying degrees of rupture or stretching of the capsule off the glenoid. Fracture of the rim of the glenoid or rupture of the capsule off the humeral head occurs occasionally. Excessive laxity of the capsule can follow repeated injury. There are no major muscular lesions associated with dislocations.

A bony lesion is produced by the impaction or compression of the posterior humeral head against the anterior rim of the glenoid at the time of the dislocation. This is called the Hill-Sachs (Hermodson) lesion of the humeral head, and this is most commonly associated with recurrent dislocation.

Symptoms and diagnosis

– Excruciating pain is felt at the time of injury and as long as the joint is dislocated.
– Lack of mobility; the arm hangs loosely beside the body.
– The upper part of the humerus can be felt as a lump in the armpit, and, where it is normally located, an empty joint socket can be felt.
– The outline (contour) of the injured shoulder looks uneven in comparison with the rounded outline of the undamaged shoulder.
– The diagnosis can be verified by X-ray. A posterior dislocation often requires an X-ray examination using special techniques.

Treatment

The injured athlete should be taken to a doctor for immediate treatment. As a rule, the earlier the joint is reduced, the fewer the complications and the shorter the healing period. It is more considerate to manipulate the joint back into position after the patient is anesthetized. An X-ray should be taken before the reduction to exclude a concurrent fracture and again after the reduction to check alignment.
After manipulation, the arm is immobilized against the body in order to reduce pain and to allow the joint capsule and ligaments to heal. The time of immobilization is controversial. The older athlete may use a sling
for 1–2 weeks, but should intermittently remove the sling to perform range-of-motion exercises. The period in a sling may be extended for the young athlete in whom the danger of redislocation is high, especially if this is a first dislocation. In recurrent dislocations, an early, thorough muscle-strength training program can be initiated. Range-of-motion exercises should under all circumstances start early.

In very active athletes with a first-time dislocation, acute arthroscopy can be of value with lavage and/or debridement, and stabilization of the labral lesion. This acute treatment is becoming more and more
common, as it seems to decrease the recurrence rate in athletes aged 16–25 years which is currently more than 85%.


Healing and complications

– If there are no complications, a dislocated shoulder heals well. Light conditioning and gentle exercise can be resumed after 2–4 weeks.
– Return to sporting activity involving the injured arm should not take place until full mobility and strength are regained, usually 2–3 months after injury.
– Sometimes a dislocation of the shoulder joint is complicated by a fracture of the upper part of the humerus or the scapula.
– In rare cases, nerve and blood vessel injuries and muscle ruptures may occur.

Patients who sustain their first dislocation before the age of 25 years are at great risk of recurrent dislocations. If dislocations occur more than three or four times, surgery to stabilize the joint should be considered. The results are good to excellent. With open stabilization, such as the Bankart procedure, the results are excellent in 90–95% of the cases; arthroscopic reconstructions have excellent results in about 80– 85% but are continuously improving. In young athletes, the open procedure is therefore still the treatment of choice. However, in older athletes, arthroscopic treatment can be attempted, provided the athlete is aware of the lower success rate. Return to sports involving the affected arm is usually possible after 4–6 months.

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