The rotator cuff refers to a group of four small muscles which run from the shoulder blade to the upper arm bone, passing through a narrow space. They stabilise and move the shoulder joint. The rotator cuff muscles attach to the arm bone by tendons. Rotator cuff tendinopathy refers to inflammation and swelling within one or more of these tendons. The rotator cuff muscle tendons pass through a narrow space between the acromion process of the shoulder blade and the head of the upper arm bone. Anything which causes further narrowing of this space can result in impingement syndrome – the rotator cuff muscles get pinched in this small space. This can be caused by bony structures such as spurs, bursitis or variations in the shape of the bones, thickening or calcification of ligaments or loss of function of the rotator cuff muscles due to injury or weakness, causing the upper arm bone to move too far up, resulting in impingement from below.
Rotator cuff tendinopathy results from overuse or injury to a rotator cuff tendon. The most commonly involved tendon is that of the supraspinatus muscle which functions to help raise the arm into the air. The tendon is susceptible to ‘wear and tear’ and repetitive use of this tendon can rub the tendon against the edges of the bony space resulting in microscopic tears within the substance of the tendon
The most common symptom is pain felt in the top of the upper arm that typically develops gradually. This is usually felt when you try to lift your arm into the air. Initially, the tendon may only be painful following exercise. For example, it may first be felt rising the day following sport participation. Stiffness or a loss of movement in the shoulder may also be accompanied by weakness. Typically, these initial signs are ignored, as they disappear quickly with use of the arm or applying heat. However, as you continue to participate, the tendinopathy progresses and the pain within the tendon becomes more intense and more frequent. The tendinopathy can worsen until you feel the pain in the arm every time you lift your arm. Pain may occur at night, especially when lying on the affected shoulder.
Tendinopathy and Impingement syndrome can usually be diagnosed by history and physical exam. X-rays of the shoulder can be used to detect some joint problems i.e. arthritis, variations in the acromion, and calcifcations. Ultrasonography and MRI can be used to detect rotator cuff pathology.
Impingement syndrome is usually treated conservatively, but can be treated with arthoscopic surgery or open surgery in severe cases. Conservative treatment includes rest, cessation of painful activity and physiotherapy focused at maintaining range of movement to avoid shoulder stiffness, retraining normal biomechanics and patterns of movement as well as rehabilitative exercise. Antiinflammatory’s, dry needling, taping and ice packs may be used for pain relief.
Therapeutic injections of corticosteroid and local anesthetic may be used for persistent impingement syndrome. The total number of injections is generally limited to 3 due to possible side effects from the corticosteroid and is performed by an orthopeadic surgeon.