Ultrasound signs of shoulder injuries and diseases

Rotator cuff injuries.

As noted above, ultrasound examination is a highly sensitive method for assessing the condition of the rotator cuff. First of all, this concerns the detection of traumatic injuries, which are characterized by significant differences in both morphology and the severity of the process. Rotator cuff tears can be complete and partial, longitudinal and transverse. Acute tears have a transverse configuration, while chronic tears are more typically longitudinal and take an oval or triangular shape. Chronic rotator cuff tears are usually present in older people who have pronounced degenerative-dystrophic processes in the joint (see impingement syndrome below). Such tears may even be asymptomatic.

The tendons of the supraspinatus and infraspinatus muscles are most often damaged, and less often - the subscapularis muscle. In case of subscapularis muscle ruptures, dislocation of the tendon of the long head of the biceps is usually observed.

There are many classifications of rotator cuff tears. The main classification of tears involves dividing them depending on the extent of damage into partial and complete. Complete tears, in turn, are also divided into several groups. The first classification is based on the greatest distance between the torn ends of the tendons. With small tears, the diastasis is less than 1 cm, with an average length - from 1 to 3 cm, with large ones - more than 3 cm, with massive ones - more than 5 cm. The classification based on the degree of involvement of the tendons of the muscles that make up the rotator cuff also distinguishes several groups of injuries. The first group of tears includes all partial (intra-trunk, intra-articular, extra-articular) or complete tears less than 1 cm. The second group - complete ruptures of the supraspinatus muscle. The third - complete ruptures of the tendon of more than 1 muscle. The fourth - massive ruptures with osteoarthritis.

The classification also provides information on the duration of the injury. There are acute injuries - less than 6 weeks, subacute injuries - from 6 weeks to six months, chronic injuries - from 6 months to a year, and old injuries - more than a year.

Classification of Rotator Cuff Tears

Depending on how long ago the damage occurred		Length of the rupture (by maximum diastasis)		Anatomical localization
Nature of the gap	Time sincebreakup	Type of break	Gap width	Groups	Length
Spicy	Less than 6 weeks	Small	Less than 1 cm	1	Partial or complete less than 1 cm
Subacute	From 6 weeks to 6 months	Average	1-3 cm	2	Complete ruptures of the supraspinatus muscle
Chronic	From 6 months to 1 year	Big	3-5 cm	3	Complete ruptures of tendons of more than 1 muscle group
Obsolete	More than 1 year	Massive	More than 5 cm	4	Massive ruptures with osteoarthritis

Complete rotator cuff tear.

In case of a complete rupture of the supraspinatus muscle, both longitudinal and transverse scanning reveals a violation of the integrity of its contours. At the site of the rupture of the supraspinatus muscle, a hypo- or anechoic cleft with uneven, blurred contours is visible. As a result of the injury, the shoulder joint directly communicates with the subacromial-subdeltoid bursa through the resulting tendon gap. Communication of the cortical layer of the humerus through the tendon gap with the subacromial-subdeltoid bursa is the main sign of a complete rupture.

When scanning, an increase in the volume of the subacromial-subdeltoid bursa is visualized, the tuberosity of the humerus is exposed at the attachment site of the deltoid muscle. Atrophy of the deltoid muscle gradually develops in the form of a decrease in its thickness, heterogeneity of structure, and unevenness of contours. A hernia of the deltoid muscle may form, which looks like a tumor-like formation of elastic consistency, decreasing in volume during muscle tension.

Partial rotator cuff tear.

With these ruptures, only a portion of the rotator cuff tendon fibers is damaged. There are several types of partial ruptures of the rotator cuff: intra-articular, extra-articular, and intra-trunk. Their schematic representation is shown in the figures. With a partial rupture of the supraspinatus muscle, a small hypo- or anechoic area with uneven, clear contours is determined in the cuff area. Intra-trunk partial ruptures are most common.

They are easiest to visualize in an orthogonal projection. The rarest extra-articular ruptures are those in which the rupture area faces the deltoid muscle and communicates with the subdeltoid-subacromial bursa.

In intra-articular ruptures, the rupture cavity faces the joint cavity and effusion is usually not observed. Another type of rupture is the so-called avulsion rupture, in which a rupture of the cartilaginous or cortical layer of the humerus is observed.

In this case, a hyperechoic linear fragment surrounded by a hypoechoic area is visualized. With repeated damage to the supraspinatus muscle, effusion appears in the subdeltoid and subacromial bursae, in the acromioclavicular joint. It is necessary to take into account that a powerful muscle layer can obscure the presence of effusion in the joint. Fluctuation of fluid is best determined along the posterior edge of the deltoid muscle or from the side of the axillary fossa.

Sonographic criteria for rotator cuff rupture.

1. Absence of visualization of the rotator cuff. It is observed in large tears, when the cuff is torn from the greater tubercle and retracts under the acromial process. In such cases, the deltoid muscle is adjacent to the head of the humerus and there is no echo signal from the rotator cuff between the deltoid muscle and the head.
2. Discontinuity of its contours. Occurs when the defect at the site of the rotator cuff rupture is filled with fluid. There is a pronounced asymmetry when compared with a healthy shoulder.
3. The appearance of hyperechoic zones in the projection of the rotator cuff. This sign is not as reliable as the previous ones. Hyperechoic zones usually occur in cases of replacement of rupture zones with granulation tissue. The symptom should be considered as a sign of rupture of the rotator cuff only in the case of pronounced asymmetry compared to the opposite shoulder.
4. The presence of a small hypoechoic band in the rotator cuff area suggests a rupture of the supraspinatus muscle. These changes are often accompanied by subacromial and subdeltoid bursitis.

Impingement syndrome and rotator cuff injuries.

It is important to remember that rotator cuff tears in the elderly are not the result of injuries, but often occur as a result of degenerative changes in the joint and its constituent elements. As a result of degenerative changes, protrusive tendinitis occurs, 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. The favorite localizations of these changes are 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 impingement syndrome. This disease is characterized by persistent degenerative changes in the paracapsular tissues of the shoulder joint and is accompanied by a variety of clinical manifestations. It often occurs with severe pain syndrome and is accompanied by varying degrees of limitation of the range of motion in the joint.

The causes of impingement syndrome development are: microtraumatic damage to the capsule, trauma to the shoulder joint complicated by a rupture of the rotator cuff, as well as diseases such as rheumatoid arthritis and diabetic arthropathy.

There are 3 stages of the disease, which usually follow one another.

Stage 1 (swelling and hemorrhage). Pain occurs after physical exertion, night pain is typical. Most often occurs at a young age. At this stage, the "arc" or "painful abduction arch" symptom is determined, when pain appears within 60-120 degrees of active abduction when the sore arm is abducted. This indicates that there is a collision between the greater tubercle of the humerus, the anterior-outer edge of the acromion and the coracoacromial ligament. Between these structures, at the site of attachment of the rotator cuff, its infringement occurs.

Ultrasound examination reveals uneven thickening of the supraspinatus tendon with hyperechoic areas of fibrosis in the joint capsule. In the projection of the apex of the acromial process of the scapula, at the site of attachment of the supraspinatus tendon to the greater tuberosity of the humerus, its thickening and subacromial bursitis are noted.

Stage two (fibrosis and tendinitis). Painful phenomena are observed in the shoulder joint with a complete lack of active movements. Occurs at the age of 25 to 40 years. 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 examination reveals heterogeneity of the structure of the supraspinatus tendon, the appearance of multiple small hyperechoic inclusions. Thickened, uneven contours of the long head of the biceps brachii with single point calcifications and effusion are visualized in the intertubercular fossa.

Stage 3 (rotator cuff tears). Patients experience persistent pain contracture with passive movements and almost complete loss of movement in the shoulder joint. It is observed in people over 40 years of age. As a result, the shoulder joint cavity significantly decreases in volume, the joint capsule becomes rigid and painful. Adhesive capsulitis develops in the periarticular tissues and synovial membrane.

Biceps tendon ruptures.

Ruptures of the biceps tendon occur when lifting heavy objects or sharply straightening the arm bent at the elbow. Most often, ruptures occur at the age of 40 and older. Predisposing factors are degenerative changes in the tendon. The main symptoms are: sharp pain, crunching at the moment of injury, decreased strength of the arm for flexion. In the upper part of the shoulder - a depression area. The torn part contracts in the distal direction and bulges under the skin. It is important to remember that assessing the condition of the long head of the biceps tendon is extremely important, since such information helps in searching for a possible rupture of the rotator cuff.

Partial ruptures. In partial ruptures of the biceps tendon, there is effusion in the synovial membrane, the tendon fibers are traceable, but there is discontinuity and fraying at the site of the rupture. On transverse scanning, the hyperechoic tendon will be surrounded by a hypoechoic rim.

Complete ruptures. In the case of a complete rupture, the biceps tendon is not visualized. On echograms, a hypoechoic area of non-uniform structure with unclear uneven contours is determined at the site of the rupture. A small depression (groove) is formed due to the depression of muscle tissue. During longitudinal scanning, the torn part of the tendon and the contracted muscle can be seen. In the energy mapping mode, increased blood flow is noted in this area.

As a rule, in practice, with traumatic injuries, we deal with combined pathology. Often, with combined ruptures of the tendons of the supraspinatus and subscapularis muscles, dislocation and subluxation of the biceps tendon is observed. In such cases, it is necessary to look for the place of its displacement, since the intertubercular groove will be empty. Most often, the biceps tendon is displaced towards the subscapularis muscle.

Fractures of the humerus.

Clinically, it is quite difficult to differentiate acute rotator cuff injuries and rotator cuff injuries in humeral head fractures. Ultrasound in the fracture area shows an uneven, fragmented bone surface. Often, humeral head fractures are combined with rotator cuff injuries. Ultrasound angiography at an early stage in the fracture healing zone usually shows pronounced hypervascularization. Sometimes, ultrasound can visualize the fistula tract, as well as cavities after osteosynthesis of the humerus with a metal plate.

Tendinitis and tenosynovitis of the biceps muscle.

Tenosynovitis of the biceps muscle is a fairly common pathology in impingement syndrome. However, it can also be combined with rotator cuff tendinitis. There is effusion in the synovial membrane of the biceps tendon, the tendon fibers are fully traced. On transverse scanning, the hyperechoic tendon will be surrounded by a hypoechoic rim. In chronic tenosynovitis, the synovial membrane will be thickened. Ultrasound angiography, as a rule, shows an increase in the degree of vascularization.

Rotator cuff tendinitis and tendinopathies.

As a result of frequent bruises of the shoulder joint, infection, and metabolic disorders in the tendons of the rotator cuff, pathological changes may occur, manifested by tendinitis, dystrophic calcification, and mucoid degeneration.

Tendinitis. Tendinitis is typical for young patients, usually under 30 years of age. Ultrasound examination reveals the appearance of hypoechoic areas of irregular shape, with uneven contours. The tendon is thickened, increased in volume and, as a rule, locally. An increase in the thickness of the tendon on the affected side by 2 mm, compared to the contralateral side, may indicate tendinitis. Ultrasound angiography may show increased vascularization, which reflects hyperemia of soft tissues.

Calcific tendinitis. Calcific tendinitis manifests itself as severe pain. During ultrasound examination, numerous small calcifications are detected in the tendons.

Mucoid degeneration. Mucoid degeneration appears to underlie the hypoechoic appearance of rotator cuff tears, which occur with progression of degenerative processes in the tendon.

Initially, mucoid degeneration appears on ultrasound examination as small hypoechoic point areas, which then become diffuse in nature.

It seems quite difficult to differentiate the presence of degenerative processes in tendons caused by the progression of inflammatory changes, age-related changes or systemic diseases such as rheumatoid arthritis.

Subacromial-subdeltoid bursitis.

The subacromial bursa is the largest bursa in the shoulder joint. Normally undetectable, it increases in size with pathological changes in the shoulder joint and is located along the contour of the rotator cuff under the deltoid muscle.

Effusion in the joint bags of the shoulder joint may occur: with rotator cuff ruptures, inflammatory diseases of the shoulder joint, synovitis, metastatic lesions. With traumatic or hemorrhagic bursitis, the contents have a heterogeneous echostructure.

With hypertrophy of the synovial membrane lining the bursa, various growths and uneven thickness of the bursa walls can be determined.

In the acute phase, ultrasound angiography reveals increased vascularization. Subsequently, calcifications may form inside the bursa.

Acromioclavicular joint ruptures.

Injuries to the acromioclavicular joint can mimic rotator cuff tears, since the supraspinatus tendon passes directly under this joint. Patients experience sharp pain when raising their arm sideways. A distinction is made between complete and incomplete ruptures of the acromioclavicular joint. A rupture of one acromioclavicular ligament results in an incomplete dislocation of the acromial end of the clavicle, while a rupture of the coracoclavicular ligament also results in a complete dislocation. With a complete rupture, the clavicle protrudes upward, and its outer end can be clearly felt under the skin. The clavicle remains motionless when the shoulder moves. With an incomplete dislocation, the clavicle maintains its connection with the acromion, and the outer end of the clavicle cannot be felt. When pressing on the clavicle, the dislocation is quite easily eliminated, but as soon as the pressure is stopped, it reoccurs. This is the so-called "key" symptom, which serves as a reliable sign of a rupture of the acromioclavicular ligament.

Echographically, ruptures of the acromioclavicular joint are manifested by an increase in the distance between the clavicle and the acromion of the scapula, compared to the contralateral side. If the clavicle and acromion are normally at the same level, then in case of ruptures the clavicle shifts upward, the boundaries of the levels change. At the site of the rupture, a hypoechoic area is visualized - a hematoma, torn ends of the thickened ligament are visible. Rupture of the fibers of the underlying subacromial bursa is accompanied by the appearance of the "geyser" symptom.

Another most typical pathology of this joint is osteoarthrosis. With this pathology, the joint capsule is stretched due to synovitis, individual fragments and "joint mice" appear in it. Osteolysis can be observed at the distal end of the clavicle. These changes are most often found in contact sports players and weightlifters. Very often, pathological changes in this joint are missed by specialists performing ultrasound examinations, since all attention is focused on the shoulder joint.

Anterior labral injuries.

In traumatic injuries to the shoulder joint, accompanied by a rupture of the joint capsule in the scapulohumeral joint, the so-called Bankart syndrome is observed, which is characterized by a rupture of the anterior glenoid labrum. The presence of effusion in the scapulohumeral joint and stretching of the capsule allow an ultrasound examination using a convex sensor to detect a rupture of the cartilaginous tissue. A Bankart rupture during an ultrasound examination is accompanied by a violation of the integrity of the contours of the anterior glenoid labrum and the appearance of fluid in the joint cavity, causing thickening and bulging of the capsule.

Posterior labral injuries.

If the damage affects the posterior labrum of the glenohumeral joint, the presence of a rupture of the cartilaginous tissue and the presence of torn bone fragments of the humeral head will be called Hill-Sachs syndrome. By analogy with ruptures of the anterior labrum, ultrasound examination also shows a violation of the integrity of the contours of the posterior labrum, the appearance of fluid, bulging and thickening of the capsule.

Rheumatoid arthritis.

Degenerative changes and tendon ruptures in inflammatory rheumatic diseases are not distinguished echographically from changes of other origins.

Rheumatoid arthritis primarily affects the joint cavity and bursa, as well as the articular surface of the bone, in the form of erosions. Erosions are visualized as small defects of bone tissue, irregular in shape with sharp edges. The subdeltoid bursa is usually filled with liquid contents. Very often, muscle atrophy is detected with this disease. The intermuscular septa become isoechoic and it is difficult to differentiate muscle groups.

In the acute phase of the disease, hypervascularization in soft tissues is clearly visible, which is usually not observed in the remission phase.

Using ultrasound angiography, it is possible to carry out dynamic monitoring of treatment for rheumatoid arthritis.

Thus, we can conclude that ultrasound examination is an important method for visualizing changes in the shoulder joint.

Modern ultrasound capabilities allow us to use it both for primary diagnostics of pathological changes in the joint and for monitoring treatment. The simplicity and reliability of ultrasound methods provide it with an undoubted priority over other instrumental methods.