Impingement syndrome of the shoulder joint is an inflammatory disease caused by compression of tendons of the rotational cuff of the shoulder between a part of the scapula – acromion (top) and the head of the humerus (bottom). Tendons of the muscles of the shoulder, during movement, are constantly in contact with the process of the scapula, are injured, movements become limited and are accompanied by pain in the shoulder.
Usually, there is a sufficient gap between acromion and the rotational cuff, so that tendons slide freely under acromion when moving in the shoulder joint. However, whenever you raise your hand, there is a slight compression of tendons and joint bursa between the head of humerus and acromion. This phenomenon is called impingement. The phenomenon of impingement occurs to one degree or another when raising hand in any healthy person.
The development of clinically pronounced impingement is facilitated by daily work with raised hands (plasterers), with constant execution of throwing movements (core pushers). Often, impingement syndrome manifests itself clinically when irritation or damage to tendons of the rotational cuff occurs. Appearance of impingement syndrome is facilitated by any condition that leads to narrowing of the gap between acromion and tendons of the rotational cuff. A common cause of this narrowing is bone spurs – spiky outgrowths emanating from the acromioclavicular joint. The acromioclavicular joint is a joint between the shoulder blade and clavicle located directly above the joint bursa and rotational cuff. In some cases, this gap is narrowed due to hypertrophic acromion. Another reason for the narrowing of this space is an abnormal inclination of acromion down.
Signs of the presence of the disease in its early stages are aching pain in the shoulder, which can appear even during sleep. Then painful sensations intensify, limited movement gradually appears. When raising or retracting arm in the shoulder, unpleasant clicking and crunching may be felt. As a result, the muscles in this area weaken, lose their tone. With further load, tendon rupture can occur, pain becomes sharp, and the joint becomes almost motionless.
Shoulder impingement syndrome at the very beginning develops as an inflammation of tendons, then in the area of inflammation dense scarring connective tissue appears – fibrosis, in the further course of the disease, fibrosis is replaced by calcium deposits. In later stages, the pain intensifies, stiffness of the joint is possible. Sometimes a click is noted in the joint at the moment of lowering arm. Weakness and difficulty in raising arm may indicate a rupture of tendons of the rotational cuff.
The main complaint of patients is dull radiating pain and restriction of movements in the shoulder joint during abduction and flexion of the shoulder. The most pronounced pain syndrome is observed when the shoulder is abducted at an angle of 30-60°, i.e. in a position in which the greater tubercle of the humerus with muscles attached to it is located under the lower edge of the acromion. With further abduction, pain decreases. Many patients note that pain prevents them from falling asleep, especially if they lie on the side of the affected joint. With long-term impingement syndrome, atrophy of deltoid, supraspinatus and infraspinatus muscles can occur.
Diagnosis is based on an analysis of the symptoms of the disease and physical examination. Doctor will ask you questions about the nature of your work since impingement syndrome is often an occupational disease. X-ray of the shoulder joint may be prescribed to detect abnormal or hypertrophic acromion or bone spurs near the acromioclavicular joint. If during the examination rupture of the rotational cuff is suspected, then magnetic resonance imaging is possible.
X-ray and MRI for impingement syndrome of the shoulder joint
Treatment for impingement syndrome always starts with a conservative one. It provides for a change in the patient’s physical activity, special exercises, physiotherapy, and the use of non-steroidal anti-inflammatory drugs (NSAIDs). Often, medical injections into the shoulder joint are resorted to.
Typically, this treatment lasts up to 2-3 months. It has high efficiency, not less than 70%. However, the ineffectiveness of conservative treatment for more than 2-3 months involves surgical treatment.
The purpose of surgery is to expand the boundaries of «bottleneck» and release sliding of the rotational cuff of the shoulder. This is performed using arthroscopy. Arthroscopic treatment of impingement syndrome is one of the most rewarding operations; it is called subacromial decompression. Rehabilitation lasts one month. Only 3-4 weeks are needed to feel the release of usual pain.
On the other hand, unjustified attempts to postpone surgical treatment reduce its effectiveness in the long term, leads to additional damage – ruptures of the rotational cuff of the shoulder.