Shoulder ultrasound for osteoarthritis

The shoulder joint is one of the most convenient for ultrasound, especially because many pathological changes occur in its soft tissues. Due to the low information content of the X-ray method in reflecting soft tissue changes, ultrasound, along with MRI, has become the leading method in the study of the shoulder joint.

Special attention during the examination should be paid to the so-called rotator cuff, formed by the tendons of four muscles: supraspinatus, infraspinatus, subscapularis and teres minor. In this case, mandatory projections are the abduction of the patient's arm into a position of external rotation (to examine the subscapularis muscle) with passive internal and external rotation of the patient's limb, placing the arm being examined behind the back with transverse positioning of the sensor (to assess the supraspinatus tendon). In practice, ruptures of the rotator cuff are often encountered, which can be complete, partial, longitudinal and transverse.

It is necessary to take into account that we are not only talking about traumatic injuries of this formation, but also about the fact that in people with osteoarthritis, especially in the elderly, ruptures often occur due to degenerative changes in the joint and its constituent elements, which result in protrusive tendinitis up to a complete degenerative rupture of the rotator cuff of the shoulder. This may be accompanied by bursitis not only in the subacromial, but also in the subdeltoid bursa. Most often, these changes are localized at the base of the tendon of the supraspinatus, infraspinatus muscle and the greater tubercle of the humerus.

All these changes can lead to the development of the so-called pingement syndrome, characterized by persistent degenerative changes in the pericapsular tissues of the shoulder joint and often accompanied by severe pain syndrome, varying degrees of limitation of the range of motion in the joint. The causes of impingement syndrome, along with osteoarthritis, are microtraumatic damage to the capsule, shoulder joint trauma complicated by a rupture of the rotator cuff, as well as diseases such as rheumatoid arthritis and diabetic arthropathy. There are three stages of the disease.

The first stage is edema and hemorrhage. Pain occurs after physical exertion, and pain that occurs at night is typical. At this stage, the "arc" or "painful abduction arch" symptom is determined, when pain appears within 60-120° of active abduction when the painful arm is abducted. This indicates that there is a collision of the greater tubercle of the humerus, the anterolateral edge of the acromion, and the coracoclavicular ligament. Between these structures, at the attachment site of the rotator cuff, it is pinched. Ultrasound shows uneven thickening of the supraspinatus tendon in the joint capsule, with hyperechoic areas of fibrosis. In the projection of the apex of the acromial process of the scapula, at the attachment site of the supraspinatus tendon to the greater tubercle of the humerus, its thickening and subacromial bursitis are noted.

The second stage is fibrosis and tendinitis. There are painful phenomena in the shoulder joint with a complete absence of active movements. Degenerative changes occur in the tendon-muscle and ligament complex of the shoulder joint. As a result, the stabilizing function of the tendon apparatus decreases. Ultrasound reveals heterogeneity of the structure of the supraspinatus tendon, the appearance of multiple small hyperechoic inclusions. In the intertubercular fossa, thickened, uneven contours of the long head of the biceps brachii muscle with single point calcifications and effusion are visualized.

The third stage - rotator cuff ruptures - is characterized by persistent painful contracture during passive movements and almost complete loss of movement in the shoulder joint. The shoulder joint cavity significantly decreases in volume, the joint capsule becomes rigid and painful. Adhesive capsulitis develops in the periarticular tissues.