Ultrasound signs of injuries and diseases of the wrist and hand joints

Tenosynovitis. One of the most common pathologies of this localization. The most common cause of tenosynovitis is rheumatoid arthritis. With the development of tenosynovitis, effusion occurs in the synovial sheath of the tendons. The synovial membrane thickens, the degree of its vascularization increases. With chronic tenosynovitis, the tendon itself is involved in the process, which can contribute to its rupture. With tenosynovitis of small tendons of the hand, detection of effusion is difficult. Indirect signs of its presence are increased echogenicity of the bone phalanx. For clarification, comparison with a symmetrical phalanx is recommended.

Tendon ruptures. Ruptures of the tendons of the wrist and hand joints are relatively rare. Chronic changes in the tendons, rheumatoid arthritis, gouty arthritis, systemic diseases, diabetes mellitus, etc. predispose to ruptures. Rupture of the extensor tendon of the finger from the attachment at the base of the nail phalanx is the most common of the subcutaneous tendon ruptures. It occurs with a sharp bending of the finger at a time when the tendon is actively contracted. Such ruptures are observed in basketball, in pianists, and surgeons. Tendon rupture may be accompanied by the rupture of a triangular fragment from the base of the phalanx. With this type of injury, the finger acquires a characteristic hammer-shaped form.

In case of a complete rupture, an empty synovial sheath with effusion is determined. In case of partial ruptures of the tendon, its structure becomes frayed at the site of the rupture, and effusion appears in the synovial sheath. In case of chronic tendinitis, hyperechoic inclusions may form in the area of tendon attachment. The tendon is usually thickened, its echogenicity is reduced.

De Quervain's tenosynovitis. Refers to idiopathic tenosynovitis. In this disease, the first canal of the fibrous reinforcing cord, in which the tendon of the short extensor of the fingers and the long tendon abducting the finger pass, in the area of the styloid process of the radius on the dorsal surface of the wrist joint, is involved in the process.

The disease affects women more often than men, in a ratio of 6 to 1. The disease occurs between the ages of 30 and 50.

Clinically, it manifests itself as a pain syndrome from the side of the radius, which intensifies when moving the fingers. Swelling of this area is noted by palpation.

Echography reveals fluid in the thickened synovial sheath of the tendons. The tendon of the short extensor of the fingers or the long tendon of the abductor of the finger are usually not thickened.

Ganglion cysts (hygromas). One of the most common pathologies of the hand tendons. A characteristic ultrasound sign of a ganglion is a direct connection with the tendon. Ganglia are oval or round in shape, enclosed in a capsule. The contents may have different consistencies depending on the duration of the disease.

Ruptures of the lateral ligaments. The most common is a dislocation of the first finger in the metacarpophalangeal joint. Sharp and excessive abduction of the first finger can lead to a rupture of the medial lateral metacarpophalangeal ligament. As a result, a subluxation of the phalanx occurs.

Dupuytren's contracture. This is an idiopathic benign proliferative process that leads to the proliferation of fibrous tissue in the palmar aponeurosis. It occurs more often in men over 30 years of age. As a rule, the tissues of the 3rd, 4th, 5th fingers are affected. In most cases, both hands are affected. Fibrous tissue appears in the fibro-fatty layer between the skin and deep palmar structures, leading to the formation of collagen nodules and cords. The palmar aponeurosis undergoes cicatricial degeneration, compaction, and wrinkling; the subcutaneous fat gradually disappears, and the skin, funnel-shaped, drawn in in certain areas, grows together with the altered thickened aponeurosis. As a result of the transformation of thin aponeurotic fibers into dense cords, the fingers bend and shorten. In this case, the flexor tendons of the fingers are not subject to pathological changes. The process develops gradually and is characterized by a wave-like chronic course. In the later stages, the disease is easily diagnosed clinically, while in the early stages, these nodules can only be recognized by ultrasound. Echographically, the changes look like hypoechoic formations lying subcutaneously, in the palmar fascia or aponeurosis.

Carpal tunnel syndrome. This is the most common pathology of compression neuropathy of the medial nerve. It often occurs in typists, cloakroom attendants, programmers, musicians, and auto mechanics. Clinically, it manifests itself as pain and paresthesia in the wrist and forearm, which intensify at night and with hand movements, sensory and motor disorders. Ultrasound examination plays an important role in establishing a diagnosis, clarifying the severity of the disease, and monitoring treatment. The main ultrasound manifestations of carpal tunnel syndrome include: thickening of the nerve proximal to the compression, flattening of the nerve inside the tunnel, anterior bulging of the flexor retinaculum of the hand, and decreased mobility of the nerve inside the tunnel. Measurements of the medial nerve are taken during transverse scanning using the ellipse area formula: the product of two mutually perpendicular diameters divided by four, multiplied by the number 7G. Studies have shown that the average area of the medial nerve in men is 9-12 mm2 ^and in women 6-8 mm2 ^. If the ratio of the width to the anterior-posterior size of the nerve exceeds 3 to 1, then carpal tunnel syndrome is diagnosed.

With the development of this syndrome, the area of the medial nerve also increases. Moreover, the increase in the transverse diameter of the nerve is directly proportional to the severity of the syndrome. If the area increases by more than 15 mm2, ^surgical correction is required. Anterior curvature of the flexor retinaculum of the wrist by more than 2.5 mm indicates the development of carpal tunnel syndrome. It was found that when the fifth finger moves, the medial nerve normally shifts by an average of 1.75±0.49 mm, while with carpal tunnel syndrome it shifts by only 0.37±0.34 mm. Using a combination of these signs together with clinical data, it is quite easy to diagnose the initial signs of the disease.

Foreign bodies. The most common location of foreign bodies is the hands. Foreign bodies can be of various natures: sewing needles, pieces of metal, fish bones, wooden splinters, thorns of prickly plants. Echographically, they look like a hyperechoic fragment in the thickness of soft tissues. Depending on the composition, there may be a distal reverberation effect (metal, glass) or a shadow (wood) behind the body.