Shoulder Instability What is it? Shoulder instability refers to when the capsule and ligaments supporting the shoulder joint become loose, enabling the bones forming the joint to move excessively on one another. How does it happen? Shoulder instability occurs when the capsule and ligaments supporting the shoulder joint become loose and allow excessive movement of the bones that make-up the joint. This most commonly occurs following a shoulder dislocation where the top of the arm bone is ‘popped out’ of its socket. This overstretches and injures the capsule and ligaments surrounding the shoulder joint, reducing their ability to support the joint and making the joint ‘unstable’. Similarly, the capsule and ligaments supporting the shoulder joint may be overstretched and damaged if they are repetitively stressed. This can occur, for example, during throwing which stretches out these structures. If performed repetitively, this can make the capsule and ligaments loose and the shoulder joint ‘unstable’. Shoulder instability may also result from ligament laxity you were born with. People with this type of laxity are often referred to as ‘double jointed’ and have loose ligaments and instability at most joints in the body. How does it feel? Shoulder instability may cause a number of sensations. In certain positions of the arm, the bones within the shoulder joint may slip or ‘sublux’. This is often felt as a clunking sensation as the bones within the shoulder joint move excessively on one another. This clunking may be associated with pain which is felt deep within the shoulder. This may create a situation where you don’t like moving the arm into the position where it clunks. In some situations you may also experience a ‘dead arm’ where the arm feels momentarily numb and weak Physio Professionals (07) 5438 9111
after the bones slip or ‘sublux’. When the capsule and ligaments supporting the shoulder joint are extremely loose, the shoulder joint may continually dislocate. What should you do? If you have or suspect you have shoulder instability, it is advised you seek the assistance of a sports physiotherapist. Shoulder instability does not get better on its own. What shouldn’t you do? If you have or suspect you have shoulder instability, you should avoid those positions or activities that are likely to cause a further episode. This may cause further damage and prolong your recovery. Could there be any long-terms effects? Shoulder instability generally does not produce any long-term effects as long as it is accurately diagnosed and appropriately treated. Treatment often involves several months of intense shoulder rehabilitation. This is often successful; however, in some situations your instability may continue to be a problem. This may result in dislocation/s of the shoulder joint and subsequent damage to surrounding structures, including nerves, bone, and the cartilage lining the joint surfaces. Damage to the cartilage may result in shoulder arthritis later in life. To treat the ongoing laxity in the capsule and ligaments supporting the shoulder joint, surgery may be required to tighten these structures and increase the ‘stability’ of the joint. Management The assistance of a sports physiotherapist is important in the treatment of shoulder instability. Initially, they can confirm your diagnosis and the extent of the damage. This may require the use of imaging techniques such as X-ray, CT scans or MRI. Following this, they can provide you with a determination of how long your rehabilitation is expected to take and determine an appropriate treatment program. This may involve the use of massage, stretches and a series of specific exercises designed to strengthen the muscles that stabilise and support the shoulder joint. Surgery to reconstruct the damaged joint lining (‘labral tear’) and tighten the loose ligaments is sometimes necessary. The sport physiotherapist is able to determine whether and when this may be appropriate in your overall circumstances.
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