OVERVIEW

Is it possible for activities such as painting, swimming, tennis and other sports that require shoulder elevation movements to be deemed responsible of causing shoulder pain in 50% of the total adult population that is annually examined by orthopedists across the world? The answer is yes, and it is justified by the existing correlation between these types of activities and subacromial impingement syndrome.
Subacromial impingement syndrome, also known as shoulder impingement syndrome, is caused by friction of the tendons that embrace the articular surface of the humerus   –and constitute the rotator cuff mechanism– which is generated when the tendons ‘‘rub’’ against the passage beneath the acromion, in other words the bony process of the scapula that extends over the shoulder joint. On account of the rotator cuff muscles partaking in all internal and external rotation movements of the shoulder joint, as well as in lifting weights, it becomes clear why individuals who engage in repetitive or overhead lifting movements are more prone to injury. Additionally, high risk groups include individuals with structural abnormalities of the acromion, expressly a more ‘‘hooked’’ acromion. 

WHICH ARE THE SYMPTOMS?
Friction between the tendons and bone leads to inflammation and the development of edema (swelling), whereas inflammation of the synovial bursa, the small fluid-filled ‘‘sac’’ located between the tendons and acromion, is another observable symptom. In older patients, irritation is potentially caused by arthritis of the small joint that constitutes the junction between the acromion and clavicle.
Due to symptoms such as inflammation and edema, subacromial impingement syndrome is frequently associated with the development of shoulder tendonitis. Pain spreads down the entire shoulder towards the elbow, and usually worsens by night-time. The patient initially experiences pain when lifting the arm overhead but gradually the condition causes pain even when the patient is at rest. As a result, the patient avoids using the affected arm, thus escalating the condition into shoulder weakness or moderate shoulder stiffness.

HOW IS SUBACROMIAL IMPINGEMENT SYNDROME TREATED?
In cases of delayed treatment, possible adverse effects include the existing inflammation advancing towards contagious tendons (biceps tendonitis), or the accumulation of intratendinous calcific deposits (calcific tendonitis). The most substantial is friction that weakens the tendons and results in ruptures (rotator cuff tears).

Diagnosis for subacromial impingement syndrome is based on a detailed medical history of the patient taken by the doctor, as well as clinical examination. X-rays are used to identify potential muscle injuries or osteophytes (small abnormal bony growths or masses), as well as morphological alterations of the bone.
Initially, conventional treatment is recommended which includes anti-inflammatory drugs, activity modifications, physiotherapy sessions and muscle strengthening exercises of the rotator cuff and scapula stabilizers. In the case of persisting symptoms, additional cortisone injections might be recommended by the doctor. Furthermore, another treatment option involves injections of autologous factors obtained from the patient’s blood in order to subdue local inflammation and stimulate tissue regeneration.
Surgical treatment is deemed necessary in cases of persistent pain after 6 weeks of conventional treatment, or after the detection of extensive tendon tears. Arthroscopic acromioplasty is performed by the surgeon. The surgical procedure involves the increase of subacromial space for the rotator cuff tendons of the shoulder, and simultaneously –if deemed necessary–debridement of the injured shoulder from osteophytes and the possible repair of torn tendons. The rehabilitation period is estimated to last approximately 6 weeks, and in cases of tears, physiotherapy sessions might also be recommended.