Chronic Shoulder pain in Overhead Athletes
Chronic Shoulder pain in Overhead Athletes
Understanding overhead sport and impingement syndrome
Athletes participating in all overhead sports such as swimming, tennis, cricket and javelin classify as overhead athletes. Subacromial Impingement Syndrome (SIS) is a condition commonly encountered in overhead athletes, resulting in longstanding and chronic shoulder pain, which worsens during repeated overhead activity. Although a complete throwing motion only lasts a few seconds, repetitive overhead motion creates significant stress on the shoulder joint, resulting in muscle imbalances which heighten the risk of developing SIS1. A late diagnosis of SIS may therefore lead to decreased sport performance while valuable training time is lost due to long periods of rehabilitation2.
Prolonged participation in overhead sporting activities may create muscle imbalances which may result in narrowing of the potential space between the anterior aspect of the acromion and the greater tuberosity of the humeral head namely the Acromiohumeral distance (AHD). Narrowing of the AHD results in compression of the subacromial soft tissue structures passing deep to the acromion through the subacromial space (SAS), resulting in SIS. Subacromial impingement is characterized by pain caused by compression of soft tissue structures (bursa and tendons) during dynamic humeral abduction (raising the arm sideways above the head)3.
Figure 1: Basic shoulder anatomy demonstrating the Acromiohumeral distance4
Factors contributing to Impingement Syndrome
1. Instrinsic factors – Includes abnormalities of the rotator cuff tendons, for example, tendon tears, tendinopathy (inflammation of the tendons) or tendon thickening as a result of intratendinous calcifications.
2. Extrinsic factors – Includes abnormalities of the surrounding structures for example narrowing of the AHD and compression of the soft tissue structures, instability of the shoulder joint or altered biomechanics of the overhead motion of the shoulder.
3. Neurological injury5.
Effect and stages of Impingement Syndrome
The first stage of impingement syndrome usually occurs as a result of excessive overhead activity during work or repetitive overhead sport which results in forward or upward displacement of the humeral head. Compression of the rotator cuff tendons and subacromial subdeltoid bursa during repetitive motion subsequently leads to swelling of the rotator cuff tendons6. Stage I impingement lesions are reversible and treated conservatively.
Untreated stage I impingement lesions may progress to stage II lesions due to repeated episodes of mechanical inflammation resulting in fibrosis of the subacromial subdeltoid bursa and inflammation of the rotator cuff tendons5,7.
Stage II impingement lesions usually affect athletes aged 25 to 40 after engaging in vigorous overhead throwing sports7. Conservative treatment is recommended for stage II lesions which include rest, anti-inflammatory medication and rehabilitation to increase scapular muscle strength and improve joint position8,9. Scapular control gained by rehabilitation leads to shoulder stability and restoration of normal force couples which limits impingement symptoms and the need for surgery9. Unsatisfactory results from conservative treatment may proceed to surgical intervention.
Stage III impingement lesions present with shoulder weakness rather than stiffness and involve bony growths and tendon rupture, occurring mostly in patients older than 40 years. Surgery is usually considered as a treatment option for stage III impingement lesions5,7.
Current trends in shoulder evaluation of the painful shoulder of an overhead athlete
Accurate static and dynamic evaluation of the shoulder and scapula is necessary for optimal diagnosis in patients presenting with shoulder pain to assist clinicians in developing a rehabilitation program for the already injured athlete. Dynamic ultrasound imaging of the shoulder can be added as an accurate tool for detecting early abnormalities which may predispose to SIS, and early prehabilitation of the shoulder girdle may prevent athletes from clinical manifestation of the condition.
1. Static and dynamic evaluation
Static and dynamic evaluation of the shoulder can be performed by a physician, biokineticist or physiotherapist.
2. X-ray imaging
X-ray imaging is important to rule out bony abnormalities in the shoulder for example joint space narrowing, shoulder dislocation, arthritis or abnormal calcification in the shoulder10.
3. Magnetic resonance imaging
Magnetic resonance imaging (MRI) is a non-invasive examination that uses magnetic fields, providing excellent detail of muscles, cartilage, tendons or nerves10. A pitfall is that dynamic imaging is not possible with MRI.
CT or MRI arthrography with contrast can accurately evaluate the labrum (cartilage rim of the shoulder joint) and shoulder capsule for diagnosing tears or small bony fractures which can indicate instability10.
5. Diagnostic arthroscopy
Surgery of the shoulder where the surgeon inserts a small camera into the shoulder joint which provides excellent diagnostic detail of the joint and soft tissue structures.
6. High frequency ultrasound
Ultrasound is a non-invasive, non-radiating, cost-effective, comfortable and dynamic examination, however limited to experienced operators, which provides extensive diagnostic information of the shoulder muscles and surrounding structures dynamic imaging of the shoulder. One of the greatest advantages of dynamic ultrasound of the shoulder, as opposed to static MRI imaging, is evaluation of the subacromial space during dynamic imaging11.
Figure 2: Example of shoulder position during ultrasound evaluation12
Figure 3: Ultrasound image of the AHD measurement12
Specific protocol for ultrasound imaging includes a detailed examination of all the structures, specific measurements of the AHD of both shoulders, measured during neutral and stress imaging and different angles of abduction of the upper arm. Asymmetric narrowing of the AHD of the dominant shoulder compared to the non-dominant shoulder during stress imaging indicates that athletes at risk for developing SIS can be identified at an early stage before clinical manifestation of SIS12.
A multidisciplinary approach including the Coach, biokineticist, Radiological services involved with medical imaging and an Orthopaedic surgeon consultation is encouraged in South Africa. With this approach overhead athletes at risk of developing injuries (SIS) can be identified at an early stage before clinical manifestation of the condition. Similarly asymptomatic athletes with rotator cuff pathology can also be identified with ultrasound imaging technology and referred to an Orthopaedic surgeon for early management
If you are an overhead athlete, or experiencing any of the symptoms highlighted in the article, make an appointment for a detailed study by our expertly trained team at Keystone Radiology today.
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- Kirchhoff C, Imhoff AB. Posterosuperior and anterosuperior impingement of the shoulder in overhead athletes – Evolving concepts, International Orthopaedics 2010;34:1049-1058.
- Silva RT, Hartman LG, de Souza Laurino CF & Rocha Biló JP. (2010). Clinical and ultrasonographic correlation between shoulder dyskinesia and subacromial space measurement among junior elite tennis players, British Journal of Sports Medicine, 2010;44: 407-410.
- Seitz AL, McClure PW, Finucane S, Ketchum JM, Walsworth MK, Boardman ND & Michener LA. The scapular assistance test results in changes in scapular position and subacromial space but not rotator cuff strength in subacromial impingement, The Journal of Orthopaedic & Sports Physical Therapy, 2012a;42(5):400-412.
- DeLee JC, Drez D & Miller MD. Orthopaedic sports medicine – Principles and Practice. 3rd Philadelphia: Saunders, 2010.
- Bigliani LU & Levine WN. Subacromial impingement syndrome, The Journal of Bone and Joint Surgery, 1997;79(12):1854-1868.
- Bureau NJ, Beauchamp M, Cardinal E & Brassard P. Dynamic sonography evaluation of shoulder impingement syndrome, American Journal of Radiology, 2006;187:216-220.
- Neer CS. Impingement lesions, Clinical Orthopaedics and Related Research, 1983;173:70-77.
- Baskurt Z, Baskurt F, Gelecek N & Özkan MH. (2011). The effectiveness of scapular stabilization exercise in patients with subacromial impingement syndrome, Journal of Back and Musculoskeletal Rehabilitation, 2011;24:173-179.
- Kibler WB. Current concepts: The role of the scapula in athletic shoulder function, American Journal of Sports Medicine, 1998;26(2):325-337.
- Brukner P & Khan K. Clinical Sports Medicine. 4th Sydney: McGraw-Hill, 2012.
- Azzoni R, Cabitza P & Parrini M. Sonographic evaluation of the subacromial space, ultrasonics 2004;42:683-687.
- Gous MM, Van Dyk B & Bruwer EJ. Ultrasound comparison of the effects of prehabilitation exercises and the scapular assistance test on the acromiohumeral distance, South African Journal of Sports Medicine, 2017;29:1-6.