The shoulder complex consists of 2 joints, the acromioclavicular joint or AC joint and the large ball and socket, glenohumeral joint. Shoulder dislocation, generally refers to dislocation of the large glenohumeral joint. Overall the stability of this joint is reliant on both the static restraints (shape of the joint and joint capsule)and dynamic restraints (rotator cuff and scapula stabilizing muscles).
A shoulder dislocation occurs when the head of the humerus is pushed out of the shallow socket of the scapula. This can occur in various directions (anterior or posterior, superior or inferior) although this almost always occurs anteriorly as this is the weakest area of the capsule. At times there can also be damage to the surrounding structures as a result of the dislocation such as bone, tendons, labrum (cartilage) or nerves and blood vessels.
POSSIBLE CAUSES:
Dislocation of the shoulder is almost always associated with trauma. This can occur with activities such as a fall onto an outstretched arm, direct force on the shoulder such as in a rugby tackle or car accident or with a sudden and very forceful movement of the shoulder such as in gymnastics.
RISK FACTORS:
- Previous dislocations/subluxations
- Hypermobility/instability of the joint
- Participating in high force/high contact sports or activities (e.g. wrestling, gymnastics, football)
- Significant weakness/poor muscle tone in the shoulder
SIGNS & SYMPTOMS
- Severe/strong pain in the shoulder
- All movements are limited and painful
- Deformed appearance
- Instability and weakness in the shoulder
- Pins & needles/numbness around the shoulder or in the arm/fingers
DIAGNOSIS
Shoulder dislocation is quite an obvious injury. A Physiotherapist or Dr will be able to make a diagnosis of your dislocation based on observation, taking a history of events leading to the injury and physical examination. At times an x-ray (or other scan) may be advised to rule out bony injury or related soft tissue trauma.
TREATMENT
Sometimes the shoulder will spontaneously relocate as you move into certain positions but if not it is strongly advisable to not try and relocate the shoulder yourself as you may cause further damage to surrounding structures, such as nerves and blood vessels. You should seek immediate treatment from a health professional as delaying treatment may lead to longer recovery &/or permanent damage. The Physio or Dr may be able to relocate the shoulder at the time however at other times it may need to be performed under sedation as pain, muscle spasm and guarding my inhibit the relocation process.
Following relocation treatment will generally include:
- Immobilization in a sling
- Ice to reduce swelling and pain
- Gentle exercises to restore range of motion and increase the strength/stability of the joint
- Pain relief/anti-inflammatory medication
- Surgical intervention in the more severe cases
PROGNOSIS
Generally, the prognosis for shoulder dislocations when managed conservatively is very good. When the shoulder dislocates, there will be stretch and/or tearing of some of the joint capsule. This will often result in ongoing laxity of the capsule, even after full recovery has been made, increasing the risk of dislocation in the future. Factors which may lead to poorer outcomes with conservative management include;
- Previous dislocation/subluxaton.
- Significant bony damage during the injury, altering the shape of the joint.
- Significant capsular and /or labral damage at the time of injury.
- Failure to undertake an appropriate course of rehab for the rotator cuff and scapula stabilising muscles.
- Return to high risk activity too quickly.
Return to sport/pre-injury activities may take anywhere from several weeks to many months, depending on the injury severity and also the type of activity being undertaken. Your Physiotherapist should provide you with a graded functional exercise program and will guide you as to when you are safe to upgrade your activity level and return to certain sports.
In the instances where conservative management has failed and multiple dislocations have occurred, consultation with a shoulder surgeon to discuss surgical repair of the shoulder to improve the passive stability of the joint may be warranted.
