Sonography of tendon pathology in the hand and wrist

Abstract

Traumatic and non-traumatic tendon lesions are common at the wrist and hand. For the diagnosis, therapy management, and long-term prognosis of tendon lesions, a detailed understanding of the complex anatomy and knowledge of typical injury patterns is crucial for both radiologists and clinicians. Improvements in high-resolution ultrasound are producing high-quality images of the superficial tendinous and peritendinous structures. Thus, ultrasound is a valuable first-choice tool for visualizing traumatic, inflammatory, and degenerative conditions of the extensor and flexor tendons, particularly with the advantage of possible dynamic examination. The additional use of duplex-Doppler and power Doppler ultrasound imaging is recommended for detection of tenosynovitis in overuse injury, inflammatory disease, infection, and after traumatic conditions. In traumatic tendon injuries, knowing the precise injury zone is important for treatment decision-making. In cases of tendon rupture, the radiologist should report the tear type (i.e., complete or partial-thickness) and assess the degree of tendon retraction and associated avulsion injury, including the degree of fragment displacement. The function of intact flexor tendons may be impaired by thickening, strain, or rupture of corresponding annular pulleys. This review describes in detail the typical ultrasound imaging features of common pathologies of hand and wrist tendons, including annular pulley lesions.

Keywords: hand; pulley injury; tendon injury; tenosynovitis; ultrasound.

Fig. 1.

Zonal classification of extensor tendon injuries: from distal to proximal, odd numbers conventionally refer to specific joint levels. In the fingers: zone I indicates the DIP joint level, zone III the PIP joint, zone V the MCP joint; in the thumb: the IP joint level is zone I, the MCP joint is zone III

Fig. 2.

Extensor pollicis longus full-thickness tear. A. Photograph showing a sutured wound over the dorsal thumb due to a penetrating injury by a glass fragment. B. After repair, long-axis 22–8 MHz US image shows signs of extensor pollicis longus retear. Note the subtotal discontinuity of the proximal tendon end (arrowheads) which appears retracted away from the sutures (thin arrow). Mild fluid (asterisk) fills the gap

Fig. 3.

Schematic drawing of the extensor mechanism of the fingers with corresponding transverse slices: (1) terminal tendon, (2) lateral conjoined tendon, (3) medial conjoined tendon, (4) lateral slip, (5) central slip, (6) medial slip (7) sagittal bands

Fig. 4.

Mallet finger. A. On a longitudinal sonogram, the extensor tendon of the fourth finger (arrows) is completely torn from the distal phalanx (Distal Ph) base. The tendon stump is thickened and hypoechoic at the level of the distal third of the middle phalanx (Middle Ph). Tendon retraction (caliper) measured 4–5 mm. B. On a longitudinal T2-weighted MRI image, the extensor tendon retraction (arrows) is shown in the same patient

Fig. 5.

Boutonniere deformity. A. Lateral radiograph and B. corresponding long-axis 17–5 MHz US image of the middle finger demonstrate a small piece of bone (arrow) avulsed from the base of the middle phalanx. In B, the donor site of avulsion (thin arrow) is shown as a small concavity at the base of the middle phalanx. The retracted fragment (large arrow) is in continuity with the central slip (arrowheads) of the extensor hood

Fig. 6.

Sagittal band injury. A, B. Transverse 17–5 MHz US images over the dorsal aspect of the metacarpal head (MetH) of the right third finger acquired in extension (A) and in clenched-fist (B) position show transient ulnar dislocation of the common extensor tendon (arrowheads) during flexion. Mild local effusion (asterisks) is observed along the tendon path. C. Correlative photograph showing tendon dislocation (arrow) on the ulnar side of the third metacarpal head

Fig. 7.

Schematic drawing of the six extensor tendon compartments of the wrist, labeled from I-VI, adapted from⁽³⁴⁾. APL – abductor pollicis longus; EPB – extensor pollicis brevis; ECRL – extensor carpi radialis longus; ECRB – extensor carpi radialis brevis; EPL – extensor pollicis longus; EIP – extensor indicis proprius; EDC – extensor digitorum communis; EDM – extensor digiti minimi; ECU – extensor carpi ulnaris; Asterisk – subsheath; LT – Lister’s tubercle; Note the retinacula for each compartment are removed for better visibility

Fig. 8.

De Quervain’s syndrome. Short- (A) and long-axis (B) 24–8 MHz US images over the radial styloid reveal a thickened, hypoechoic retinaculum (arrowheads) and the swollen abductor longus and extensor pollicis brevis tendons. Note that the two tendons form a rounded complex and cannot be separated from each other, being constricted by the abnormal retinaculum

Fig. 9.

De Quervain’s syndrome in a 20-year-old patient, related to selective entrapment of the extensor pollicis brevis by a thickened retinaculum. A. Transverse US image shows a vertical septum (thin white arrow) dividing the two tendons in the first compartment. Fluid (thick white arrow) is seen surrounding the extensor pollicis brevis tendon (EPB; yellow asterisk) due to tenosynovitis. Note the thickening of the surrounding retinaculum (yellow arrow heads). The abductor pollicis longus (white asterisk) and the ventral part of the retinaculum (white arrowhead) are unaffected. The transverse color Doppler image (B) and transverse power Doppler image (C) show increased vascularization (arrow heads) surrounding the EPB tendon due to tenosynovitis

Fig. 10.

Distal intersection syndrome. A. Proximal to the criss-crossing point, transverse 17–5 MHz US image shows a distended sheath (asterisk) of the extensor pollicis longus (EPL) as it runs alongside the ulnar aspect of the extensor carpi radialis brevis (ERCB) and extensor carpi radialis longus (ECRL). B. More distally, transverse 17–5 MHz color Doppler US image demonstrates the extensor pollicis longus (EPL) as it crosses over the extensor carpi radialis brevis (ECRB) and longus (ECRL) tendons. The sheath of the second and third compartments appears mildly distended by tenosynovitis with effusion (asterisk). Note diffuse local hyperemia and the swollen appearance of the ECRB

Fig. 11.

Tenosynovitis of the fourth extensor compartment in a patient with psoriatic arthritis. A. Longitudinal US image with fluid, thickened synovium, and thickened retinaculum (white arrows) around the tendons in the fourth extensor compartment and increased vascularity on longitudinal (B) and transverse color Doppler (C) images, both in the synovium and the tendons

Fig. 12.

Screw tip impingement and tear of the extensor indicis proprius tendon in a 45-year-old woman after volar plating for distal radial fracture. A. Transverse 17–5 MHz US image obtained at the level of Lister’s tubercle (LT) reveals the thread and tip of a screw (thin arrow) impinging the extensor indicis proprius tendon. Note the intact extensor pollicis longus (EPL) and the displaced slips of the extensor digitorum communis (EDC). B. Transverse 17–5 MHz US image obtained proximal to A demonstrates the retracted extensor indicis proprius (arrowheads) surrounded by effusion and debris (asterisk). C. Longitudinal 17–5 MHz US image demonstrates the screw (thin arrow) and the empty sheath (asterisks) of the extensor indicis proprius filled with debris and hypoechoic effusion. Note the normal-appearing tendons of the extensor digitorum communis (EDC) as they run more superficially

Fig. 13.

DExtensor carpi ulnaris (ECU) instability. ECU instability in a patient with long-standing rheumatoid arthritis. US image demonstrates the ECU tendon (white asterisk) dislocated out of the groove (white arrows). The subsheath (void arrowheads) appears lax, wavy, and displaced out of the groove

Fig. 14.

Drawing of the flexor tendons of the finger, superimposed on US image. Superficial – flexor digitorum superficialis tendon (yellow), Deep – flexor digitorum profundus tendon (green), DIP – distal interphalangeal joint, PIP – proximal interphalangeal joint, MCP – metacarpophalangeal joint, VP – volar plate

Fig. 15.

Schematic drawing of superficial (red) and deep (orange) finger flexor tendons with corresponding transverse slices. Palmar plate (blue), bone (grey)

Fig. 16.

Zonal classification of flexor tendon injuries: Zone I distal to the flexor digitorum superficialis (FDS) insertions, Zone II between the FDS insertions and the level of A1 pulleys, Zone III between the proximal aspect of A1 pulleys and the lumbricals origin from the flexor digitorum profundus (FDP) tendons, Zone IV at the carpal tunnel region, Zone V from the distal myotendinous junction to the carpal tunnel, TI distal thumb to the IP joint, TII between thumb IP joint and A1 pulley, and TIII at the thenar eminence

Fig. 17.

Jersey finger. Long-axis 12–5 MHz US image of the middle finger reveals fracture of the volar aspect of the base of the distal phalanx with fragmentation (thin arrow) and proximal migration of a small piece of bone (void arrow) up to the distal edge of the A3-pulley. Note the flexor digitorum profundus tendon (white arrowheads) attached to the avulsed fragment and the empty sheath (void arrowheads) distal to it. DPh – distal phalanx; MPh – middle phalanx; PPh – proximal phalanx

Fig. 18.

Trigger finger. A. On an axial sonogram at the level of the fourth metacarpal head (Met IV), the A1-pulley (straight arrows) is thickened (1.5 mm). Its collateral ligaments appear artifactually hypoechoic due to anisotropy. Note the healthy A1-pulley (curved arrow) at the level of the third metacarpal head (Met III). B. On a longitudinal sonogram, A1-pulley thickening is shown. The flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) tendons show fibrillar echotexture and synovial sheath effusion (asterisks) is seen proximally. Hash marks indicate articular cartilage; Met – metacarpal; Prox Ph – proximal phalanx; VP – volar plate

Fig. 19.

Schematic drawing of annular pulleys (A) and longitudinal US image (B) at the level of the proximal phalanx (PP) with normal thin appearance of the A2-pulley ligament (white arrows). Note the normal tendon-to-bone distance (TBD) of <2 mm (yellow double arrow). Flexor tendons (asterisks)

Fig. 20.

Transverse (A) and sagittal (C) US with normal thin appearance of A2-pulley (white arrowheads) with normal tendon-to-bone distance (TBD) in a non-climber. Transverse (B) and sagittal (D) US shows thickened A2 ligament (white arrowheads) due to chronic overuse in a climber. Images courtesy of Prof. A. Schweizer, Handsurgery, Balgrist University Hospital

Fig. 21.

Annular pulley injury. A. Longitudinal 17–5 MHz US image obtained over the injured right long finger of a 15-year-old boy during resisted flexion of the distal interphalangeal joint demonstrates bowstringing and volar displacement of the flexor tendons (arrows) secondary to acute rupture of the A2-pulley. In this particular case, there was also a combined injury of the A3- and A4-pulleys (not shown). An increased tendon-to-bone distance (>2 mm, double arrow), is seen over the proximal phalanx. Note an abundant effusion (asterisks) distending the tenosynovial sheath. B. Corresponding photograph shows volar soft-tissue swelling over the proximal (thin arrow) and middle (arrowhead) phalanges due to bowstringing of the flexor tendons. C. Longitudinal 17–5 MHz US image over the left long finger illustrates the normal A2-pulley as a thin hypoechoic band (white arrowheads) retaining the flexor tendons (arrow) against the shaft of the proximal phalanx