The shoulder joint has the greatest freedom of movement compared to any other joint in the body. To achieve this wide range of motion, however, there is a compromise in stability, making this joint vulnerable to injury. A very common type of shoulder injury is shoulder tendonitis. Sports that are upper body dominant and place great demands on the shoulder joint such as handball, tennis, volleyball, skiing, swimming, weightlifting and ice hockey are at high risk of shoulder injury due to repetitive loading of the shoulders and intense practice.
Pain can originate from tendons, which are connective tissue structures that connect muscle to bone, or the bursa which is a fluid sac lining the tendons. Traditionally, pain in and around the tendons have been termed tendonitis, which implies inflammation. Studies have found, however, little or no signs of inflammation have been found on biopsy examination. Clinically, the prescription of non-steroidal anti-inflammatory drugs (NSAIDs) has also had limited success for cases of pain due to tendon overuse. The term “tendinopathy” is therefore the preferred term.
In the shoulder, there are two main groups of tendons that can give rise to shoulder tendonitis: rotator cuff tendons and biceps tendons. The rotator cuff is a group of four muscles that attach the arms to the shoulders and allows the arms to rotate and lift upwards, while the biceps are found at the front of the upper arm, stabilizing it in the shoulder socket, and helps accelerate and decelerate the arms in overhead movement like those made in tennis and baseball pitching. Rotator cuff tendinitis causes pain in the tip and upper -outer region of the shoulder while the biceps tendinitis causes pain at the front or side, and which might also travel downwards to the elbow and forearm.
Common symptoms of shoulder tendonitis are:
- Pain at the tip and upper outer part of the shoulder (rotator cuff tendonitis).
- Pain at the front or side of the shoulder, which may travel down to the forearm (biceps tendinitis).
- Pain aggravated by overhead reaching, pushing pulling, lifting and sleeping on the affected side.
Clinical diagnosis of shoulder tendonitis should include a physical examination and a thorough history. Physical examination should include palpation (touching) of spots to locate areas of tenderness. There are also physical tests that load tendons and alternate structures to determine where the pain is coming from. The following five tests are commonly used to diagnose shoulder tendinitis:
- Neer’s Test
With the arm at the side of the body, and elbow fully extended, the examiner turns the elbow internally and then raises the straightened arm through the full range or until complaints of pain.
- Hawkin’s-Kennedy Test
For this test, in the starting position, the arm is first raised to 90o and the elbow bent at 90o.
- Empty Can Test
In this test, the arms are raised at 90o in the scapular plane (that is, about 30o forward). The thumbs are pointed downwards, as if emptying a beverage can. The examiner then pushes down on the arm close to the wrist, while the patient resists.
- Painful Arc Test
In this test, the arm is raised in the scapular plane until there is a pain. The patient is then instructed to continue raising the arm to 180 o and then lower the arm back to the side. If the test is positive, pain is felt between 60 and 120o elevation.
- External Rotation Test
In this test, the patient has their arms bent to 90o and the examiner applies an internal pushing force to move the arm towards the body as the patient resists.
Diagnosis of shoulder tendonitis can also be assisted using imaging techniques such as ultrasound and magnetic resonance imaging (MRI).
The treatment of shoulder tendonitis is based on the nature and severity of the injury, with conservative, non-invasive treatment usually explored before moving on to more invasive treatment options. Proper rest, stretching and strengthening exercises and non-steroidal anti-inflammatory drugs (NSAIDs) are the typical treatment options for painful tendons. It should be noted, however, the long-term use of NSAIDs and corticosteroidal drugs have significant negative effects on tendon healing. Ultrasound, laser, and electrical stimulation havve been theorized to help in tendon healing, however, this has not been confirmed through clinical studies.
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