Shoulder Instability

Functional Shoulder Instability

Article by J. MillerS.Armfield

What is Functional Shoulder Instability?

Functional shoulder instability refers to increased movement of the humeral head in the socket. This can result in abnormal stressing of other structures around the area.  It is a diagnosis which can range from mild, unidirectional instability; to multidirectional instability and recurrent dislocations. 

If left untreated, it can increase your risk of developing a variety of injuries ranging from shoulder impingement and bursitis to rotator cuff tears, labral tears and dislocations. 


There are a variety of factors which can increase your risk of developing shoulder instability. These include:

  • Bone shape
    • You obviously can’t help the size of your shoulder joint surfaces, but research shows that those with a smaller or flatter joint sockets are at a greater risk of having shoulder instability.
  • A Lax, or “loose”, shoulder joint capsule 
  • Poor muscle control
    • This is something you can change! The rotator cuff complex consists of four muscles around the shoulder blade. These muscles are designed to control the movement of the glenohumeral joint and centre the arm bone in the socket during movement.
    • Muscles around the shoulder blade and chest are also critical in providing a stable base for the shoulder to move upon
  • Muscle tears
    • Especially involving the rotator cuff complex!
    • These can either be traumatic or related to overuse.
  • History of shoulder trauma (i.e. dislocation/subluxation)

What are the Symptoms of Shoulder Instability?

Some symptoms you may experience with shoulder instability include:

  • Pain- either vague or catching.
  • Weakness on the affected side
  • Heaviness or “dead arm” feeling.
  • Clicking
  • Looseness of the shoulder joint 
  • Difficulty performing specific tasks: e.g. throwing a ball, bench press, push-ups.

How is Functional Shoulder Instability Diagnosed?

Your physiotherapist will conduct a series of tests which evaluate the strength and control around your shoulder in different positions. A physical assessment of your shoulder is the best way to diagnose functional shoulder instability. 

Imaging may identify any underlying or secondary issues such as a muscle tear or bony abnormality; however, it is not able to show functional instability. 

If you have any questions about your shoulder, please ask your shoulder physiotherapist.

Treatment for Functional Shoulder Instability

Research shows that the best initial treatment for people experiencing functional shoulder instability is an individualised strengthening program (Watson 2013). Your physiotherapist will expertly assess your muscle function around your shoulder and shoulder blade, and will develop an appropriate program for you!

Will You Need Surgery?

The good news is that many people experiencing functional shoulder instability actually do very well with conservative physiotherapy treatment! 

Surgery may be considered in those cases where there is a secondary anatomical problem present; such as a labral tear, muscle tear or Hill-Sachs lesion. In some cases where laxity of the shoulder joint capsule (rather than muscle control) is the primary problem, shoulder stabilisation surgery may be warranted following unsuccessful conservative management. 


The resolution of your symptoms relies on the strengthening of weakened muscles. This takes time! In most cases, you should begin to notice an improvement in your symptoms between two to three weeks. 

The total rehabilitation time will depend on your level of dysfunction. People who display signs of mild, unidirectional instability with no previous history of shoulder problems will obviously have a quicker chance at recovery than those who have multidirectional instability, multiple dislocations and concurrent shoulder blade dysfunction. Your compliance with the exercise program also has a huge impact on your recovery time. Functional shoulder instability will not get better if you do not improve the strength and control around the shoulder! 

Will A Shoulder Brace Help?

A brace may help to temporarily relieve your symptoms in severe cases, or provide extra support to the shoulder in early-stage rehabilitation. It is certainly not a solution to the problem. In fact, long term use of a shoulder brace will possibly aggravate your condition further due to underactivity of the muscles. 

More Information

For more information, please do not hesitate to ask your shoulder physiotherapist. 

Common Shoulder Pain & Injury Conditions

Rotator Cuff

Adhesive Capsulitis

Shoulder Bursitis

Shoulder Instability

Acromioclavicular Joint

Bone Injuries

Post-Operative Physiotherapy

Muscle Conditions

Systemic Conditions

Referred Pain

Shoulder Treatment

Researchers have discovered that managing your shoulder injury with physiotherapy is usually successful. Typically, you have two options: non-operative or a surgical approach. Your condition will dictate which option is best for you at this time. Non-operative care is conservative rehabilitation.

If shoulder surgery is required, then your physiotherapist may undertake:

Pre-operative rehabilitation  - to either trial a non-operative/conservative treatment approach or to condition and prepare your shoulder and body for a surgical procedure.

Post-operative physiotherapy - to safely and methodically regain your normal range of movement, strength, speed and function.

PhysioWorks physiotherapists have a special interest and an excellent working relationship with leading shoulder surgeons. Our physiotherapy team provide you with both conservative and post-operative shoulder rehabilitation options. We aim for you attaining the best possible outcome for your shoulder injury.

For specific information regarding your shoulder, please consult your trusted shoulder physiotherapist.

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