Health & Fitness
All about Better Health and Fitness

Shoulder Joint Dislocation

A joint dislocation occurs when the two joint surfaces, which normally sit in intimate contact with each other, are wrenched away from each other to lie apart without any relationship. Joints have a surrounding ligamentous bag called a joint capsule and this can be typically injured as the surfaces force their way past each other. The surfaces of the joints themselves can be damaged as they hit each other on the way to becoming dislocated. Other injuries which can occur include damage to the local nerves and ligaments.

Of all joint dislocations, shoulder dislocations are the most common, making up almost half the total number of this kind of joint injury. An anterior dislocation, with the head of humerus coming off the shoulder socket to the front, is the most common form of this condition. The most usual position for the shoulder to dislocate in is when there is a force applied to the back of the arm with the arm in an outwardly rotated, extended and abducted position. Less commonly a blow to the back of the arm might do it, or a fall on the hand or just moving the arm forcefully outwards and rotating it externally.

Dislocations backwards are not common and due to force applied to the arm when it is over the body and turned inwards, with epileptic seizures and electrocution being possible causes as the big chest and back muscles pull the joint out due to spasms. The joint can also dislocate downwards if the arm is moved outwards and sideways with excessive force, levering the joint out against the part of the shoulder blade above it. This type of injury needs careful monitoring as it is more likely to be associated with other soft tissue injuries such as nerve injury, damage to the blood vessels and tears to the rotator cuff muscles.

There may be no trauma in some cases of shoulder dislocation and instability of the shoulder may occur in all joint directions, typical presenting in patients who have hypermobile joints. This condition is called multidirectional instability and tends to happen in both shoulders, run in the family and be in younger people under thirty. A joint subluxation is often the start of these problems, where the joint slips partly off its partner to an amount and then clicks back into place. An ability to voluntarily dislocate the shoulder can occur, perhaps related to psychiatric difficulties in this group of people.

The presentation of anterior dislocation of the shoulder is for the patient to hold their arm rotated outwards and slightly to the side, the arm bone head easily felt at the front of the joint. The shoulder muscles may be in a powerful spasm and trying to move the shoulder results in high levels of pain. A dislocation of the shoulder posteriorly shows itself by the patient keeping the arm close to the body and turned inwards, the head of the humerus being palpable at the rear of the joint, although this condition has been misdiagnosed as frozen shoulder.

The relocation of a shoulder dislocation is performed by surgeons in many different ways and the time from the incident to when the joint is finally relocated is the important matter. If the time is too long the muscle spasm increases and interferes with fixing the dislocation. An original way was to put a foot in the person’s axilla to make one end secure and traction the arm lengthways until the reduction is effected. Techniques have developed and an effective modern way is to abduct the shoulder whilst pushing the humeral head anteriorly, then rotate the arm externally and traction the arm, leading very often to success.

A significant part of a shoulder dislocation is pain and doctors have many ways of ensure the best pain relief and make the reduction process as easy as it can be. If the dislocation is recent then the joint may be relocated without much in the way of analgesics or muscle relaxing drugs. The best sedatives used have a fast mode of action, good muscular relaxation properties and short duration of action so the patient recovers quickly. Once relocated the arm should be placed in a sling which may be retained for up to three weeks to allow the capsular tear to heal.

Jonathan Blood Smyth, editor of the Physiotherapy Site, writes articles about Physiotherapy, back pain, orthopaedic conditions, neck pain, injury management and physiotherapists in Brighton. Jonathan is a superintendant physiotherapist at an NHS hospital in the South-West of the UK

Leave a Reply

Your email address will not be published. Required fields are marked *