Impingement syndrome occurs when the tendons of the shoulder are pinched against the roof of the shoulder and the acromion. Impingement syndrome usually occurs due to a muscle imbalance around the shoulder. There are several soft tissue structures that can get trapped between the humerus (the long bone of the arm) and the acromion (the point of the shoulder) and can cause pain. The structures that are commonly affected are the rotator cuff, sub-acromial bursa and the biceps tendon.
Usually there is enough room between the acromion and the rotator cuff so that the tendons slide easily underneath the acromion as the arm is raised, but each time you raise your arm the soft tissue swells and there is a bit of rubbing and pinching on the tendon and bursa, called impingement.
Sometimes small bone spurs can reduce the space that is available for the bursa to move under the acromion and this is usually caused by wear and tear of the joint between the collarbone and the scapula, called the acromioclavicular joint (AC) which is directly above the bursa and rotator cuff tendons. In some people the space is too small because the acromion is oddly sized and tilts too far down reducing the space in the AC joint.
Continuously working with the arms raised overhead, or repeated throwing activities, or other repetitive actions of the shoulder can cause impingement and become a problem e.g. painting. Impingement can also be caused by an over-mobile shoulder. There are three types of impingement which are biceps impingement, supraspinatus impingement and sub-acromial bursa impingement
Common Management Techniques
Avoidance of any activities that cause pain in the shoulder.
Improvement of shoulder mechanics to prevent further impingement of tendon. This may include:
Massage and stretching
Strengthening of weak muscles
Activities to Change your pattern of movement
Use of anti-inflammatory tablets or steroid injections.
Physiotherapy treatment will assist recovery and may consist of:
Initially the pain may worsen with treatment due to the inflammatory nature of the injury.
In severe cases, surgery may be necessary to repair tears and/or decompress the tendons.
Impingement syndrome is considered a self-limiting disorder. It is important that all the biomechanical factors that are contributing to the disorder are addressed and considered for it to resolve. For some people a course of physiotherapy for 6 weeks may be suitable, for other it may be ongoing. Some patients who do not respond to conservative management may need to go on to having surgery or the use of a sub-acromial Cortisone injection to aid in management of the disorder combined with exercise therapy.