Shoulder impingement is a condition where the bursa or rotator cuff tendons are compressed in the subacromial space, the area between the head of the arm bone (humerus) and the acromion, a bony prominence at the top of the shoulder joint. Impingement of the shoulder can be caused by bony spur on acromion, poor posture, weakness of the rotator cuff muscles or muscle tightness. Shoulder impingement may also be associated with rotator cuff tear or tendinopathy, an overuse injury.
Bursitis is an inflammation of a fluid filled sac in the joint called bursa. The bursa reduces friction between muscles, ligaments and bones. The shoulder is a ball-and-socket joint and the bursa is commonly inflamed in the subacromial space. Therefore, another term for shoulder bursitis is subacromial bursitis
The cause of shoulder bursitis is usually due to overuse of the shoulder from activities such as throwing, swimming, cleaning or gardening. Subacromial bursitis is commonly related to shoulder impingement. The onset of pain is usually gradual, but sudden onset of pain can happen from direct trauma to the shoulder, such as a fall.
Shoulder bursitis results in pain with reduced range of motion (painful arc). The pain can be aggravated by lifting, overhead movements, lying on affected side or positions that reduces the subacromial space (e.g. reaching across, hands behind back or rotating arm inward).
Apart from the history of presenting complaint, your physiotherapist will assess the shoulder with a series of tests to assist in the diagnosis of shoulder bursitis. Shoulder bursitis may be concurrent with other conditions so sometimes X-ray, ultrasound or MRI scans can be helpful to differentiate between other pathologies.
The first step to treat shoulder bursitis is to avoid aggravating positions or activities that cause the microtraumas to reduce exacerbation of symptoms. Icing for 15min every 2-3 hours may be beneficial to reduce the inflammation for the first 48-72 hours. Nonsteroidal anti-inflammatory drugs such as ibuprofen can useful to reduce pain. Rehabilitation commonly involves postural correction, manual therapy, taping and exercises that strengthens and stretches weak or tight muscles. In persistent or severe shoulder bursitis that affects activities of daily living or sleep, your physiotherapist may refer to your medical practitioner for an ultrasound-guided corticosteroid injection to reduce the inflammation. However, evidence suggests that the effects of corticosteroid injections are only short-term and the injection alone should not be favoured over physiotherapy. Therefore, it is crucial to continue with the exercises prescribed by your physiotherapist for positive long-term outcomes.