What is Shoulder Instability?
The main shoulder joint is a ‘ball and socket’ joint, made up of the humeral head (upper arm) and the glenoid fossa on the scapula (shoulder blade). The main purpose of the shoulder joint is to provide a wide range of mobility, making it the most mobile joint on the body. The glenoid fossa is very shallow to contribute to this mobility, and as such, sacrifices bony stability. The shoulder becomes heavily reliant on soft tissue structures to remain stable, but when these structures are stretched or damaged pain, instability or even shoulder dislocations can occur.
What is a Shoulder Dislocation?
When the humeral head and the glenoid fossa lose their congruency, it is called a shoulder dislocation. This can happen because of direct and indirect trauma to the shoulder, or because of the predisposed laxity of the shoulder.
Anterior and Posterior Dislocations
Shoulders can dislocate in any direction from the glenoid fossa. Most commonly they will dislocate out the front, and this is called an anterior shoulder dislocation. This generally happens with the arm stretched out to the side or from force to the shoulder from behind. Less common, and often more problematic, are posterior dislocations when the shoulder will dislocate out the back of the glenoid fossa.
In some cases, the shoulder can partially dislocate and the return into the joint space. This is often because of laxities to the soft tissue support structures and when there hasn’t been enough force to produce a full dislocation.
What causes shoulder instability?
Shoulder dislocations are a common cause for ongoing instability, this is because they can damage or disrupt the bony or soft tissue support at the shoulder. In other cases, there may be atraumatic or even congenital causes of shoulder instability.
What is AMBRI?
AMBRI is an acronym that stands for; Atraumatic, Multi-directional, may include a Bankart lesion, Recurrent Instability. This is when there has been no significant injury to the shoulder but there is increased joint laxity and instability in more than one direction. Often certain sports (like swimming or throwing sports) can result in atraumatic laxity. Some people congenitally have increased laxity in their ligaments, such as; people with hyper-mobility or people with congenital conditions like Downs Syndrome.
What is TUB’s Instability?
TUB’s stands for Traumatic, Unilateral and may involve a Bankart lesion. This type of instability occurs following a traumatic shoulder dislocation. This dislocation will often damage some of the soft-tissue or bony support structures in the shoulder, and the shoulder will then be less stable in certain directions.
How can you help me with my Shoulder Instability?
Your physiotherapist will be able to construct an individualised treatment plan based on a thorough examination into your condition, and the underlying cause of your shoulder instability. Your physiotherapist will look into the strength, mobility and stability of the shoulder and the surrounding structures in your body to tailor your specific program. It will likely involve treatment to correct abnormal movement at your shoulder and specific rotator-cuff exercises to improve their strength and stability. A full program will incorporate exercises tailored to your specific goals.
What should I do to avoid aggravating my Shoulder Dislocation?
- Follow the ADVICE of the doctor that you saw, if you had a full dislocation
- AVOID overhead activities, or activities that involve reaching behind you, particularly during the acute phase.
- Discuss pain relief or non-steroidal anti-inflammatories with your pharmacist
- DO concentrate on maintaining good, posture, particularly with activities using your shoulders.
- REMAIN ACTIVE, but avoid aggravating activities.
- RECEIVE physiotherapy care to get your joints, ligaments and muscles performing to their optimum level
Keep good care of your body and your physiotherapist will continue to monitor your condition. Once your Shoulder Dislocation has resolved you will be able to resume your full activities. However, it is very common to dislocate your shoulder a second time once it has occurred once. Be careful!