What is shoulder instability?
This is when there is too much movement between the 2 main bones that make up the shoulder joint (humeral head and glenoid). This may be experienced as painful or as apprehension of the movement potentially being too much to tolerate.
Dislocation is when the joint is completely displaced and generally needs a medical professional to relocate it. This is normally as a result of trauma.
Subluxation is when the joint is mildly displaced (partially dislocated) and can be relocated by the individual.
Causes of shoulder instability
Shoulder instability can be caused by trauma
The most common cause is sporting and rough-housing injuries especially amongst young males (they seem to be less risk averse).
It is more common amongst older (61-70 years) than younger women. This may be associated with more fall injuries.
Motor vehicle accidents are also a common cause of traumatic shoulder dislocations.
Atraumatic risk factors for developing shoulder instability
- Increased levels of the hormone serum relaxin (associated with menstrual cycles and pregnancy) has been shown to be associated with shoulder instability.
- Generalised ligament laxity
- Ehlers Danlos Syndrome
- Generalised joint hyper-mobility
- Sport – due to repetitive use, the shoulder adjusts to the need for mobility
- Poor sense of knowing where the limb is compared to the space around it
- Poor muscle control of the deltoid muscle
- Poor control of the shoulder blade movement (reduced upward rotation).
How to make sure you get the best outcome after a shoulder dislocation/subluxation?
If the shoulder has dislocated and is stuck (mostly from trauma)
Get it relocated as soon as possible by a healthcare professional such as a trauma or sports or orthopaedic specialist. They will check if there are any fractures or other soft tissue injuries such as a rotator cuff tear
If surgery is not required, wear a sling for 7 days and slowly start mobilising with the help of a physiotherapist.
If the shoulder has spontaneously relocated (mostly atraumatic subluxations)
See a healthcare professional to get x-rays and an assessment to determine if there are any fractures, nerve or vascular damage.
Wear a sling for 7 days and slowly start to mobilise with the help of a physiotherapist.
It takes a minimum of 6 weeks for any soft tissue to heal, so don’t be in a rush to get back to your sports. Trust the healing process.
You will need to slowly strengthen the shoulder in order to build up the capacity of the tissues to tolerate load again. A physiotherapist can help you learn to trust your shoulder and get it strong.
Do you get spontaneous and recurrent subluxations of your shoulder(s)?
If there is no history of a previous traumatic dislocation, you may have generalised hyper-mobility. A physiotherapist can take you through a test to determine if you may be hyper-mobile and in so perhaps establishing one of the factors that may be contributing to the shoulder instability. It is quite common, 4-13% of the population.
If you don’t want to wait, answering these 5 questions with a score of 2 or more, you’re likely to have generalised joint hyper-mobility. (1)
|1. Can you now (or could you ever) place your hands flat on the floor without bending your knees?|
|2. Can you now (or could you ever) bend your thumb to touch your forearm?|
|3. As a child did you amuse your friends by contorting your body into strange shapes OR could you do the splits?|
|4. As a child or teenager did your shoulder or kneecap dislocate on more than one occasion?|
|5. Do you consider yourself double-jointed?|
Working in conjunction with a physiotherapist to build a long-term plan to strengthen the the shoulder as well as surrounding body parts is helpful in reducing pain experience and subluxations. Exercises will also include developing the ability to feel where your joint is in space (proprioception), better motor control (awareness of movement/muscles used) and increasing endurance/tolerance of muscles to load.
Glans M, Humble MB, Elwin M, Bejerot S. Self-rated joint hypermobility: the five-part questionnaire evaluated in a Swedish non-clinical adult population. BMC Musculoskelet Disord. 2020;21(1):174. Published 2020 Mar 17. doi:10.1186/s12891-020-3067-1
This content is for education and information purposes only. It is not intended to replace professional medical advice, diagnosis or treatment. If you have any health concerns or pain, please contact your local healthcare provider directly.