Shoulder Instability

Functional Shoulder Instability

Article by John Miller

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 that can range from mild, unidirectional instability; to multidirectional instability and recurrent dislocations. 

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


There are a variety of factors that 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 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 exercise.
    • 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 that 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 cannot 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 develop an appropriate program for you!

Will You Need Surgery?

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

Surgery may be considered in cases where a secondary anatomical problem is present, such as a labral tear, muscle tear, or Hill-Sachs lesion. In some instances 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 have a quicker chance at recovery than those who have multidirectional instability, multiple dislocations and concurrent shoulder blade dysfunction. Functional shoulder instability will not get better if you do not improve the strength and control around the shoulder! Your compliance with the exercise program also has a significant impact on your recovery time. 

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

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

PhysioWorks physiotherapists have a particular 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 to attain the best possible outcome for your shoulder injury.

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

Acute Injury Signs

Acute Injury Management.

Here are some warning signs that you have an injury. While some injuries are immediately evident, others can creep up slowly and progressively get worse. If you don't pay attention to both types of injuries, chronic problems can develop.

For detailed information on specific injuries, check out the injury by body part section.

Don't Ignore these Injury Warning Signs

Joint Pain

Joint pain, particularly in the knee, ankle, elbow, and wrist joints, should never be ignored. Because these joints are not covered by muscle, pain here is rarely of muscular origin. Joint pain that lasts more than 48 hours requires a professional diagnosis.


If you can elicit pain at a specific point in a bone, muscle, or joint, you may have a significant injury by pressing your finger into it. If the same spot on the other side of the body does not produce the same pain, you should probably see your health professional.  


Nearly all sports or musculoskeletal injuries cause swelling. Swelling is usually quite obvious and can be seen, but occasionally you may feel as though something is swollen or "full" even though it looks normal. Swelling usually goes along with pain, redness and heat.

Reduced Range of Motion

If the swelling isn't obvious, you can usually find it by checking for a reduced range of motion in a joint. If there is significant swelling within a joint, you will lose range of motion. Compare one side of the body with the other to identify major differences. If there are any, you probably have an injury that needs attention.


Compare sides for weakness by performing the same task. One way to tell is to lift the same weight with the right and left sides and look at the result. Or try to place body weight on one leg and then the other. A difference in your ability to support your weight is another suggestion of an injury that requires attention.

Immediate Injury Treatment: Step-by-Step Guidelines

  • Stop the activity immediately.
  • Wrap the injured part in a compression bandage.
  • Apply ice to the injured part (use a bag of crushed ice or a bag of frozen vegetables).
  • Elevate the injured part to reduce swelling.
  • Consult your health practitioner for a proper diagnosis of any serious injury.
  • Rehabilitate your injury under professional guidance.
  • Seek a second opinion if you are not improving.