Acute and chronic wrist and hand conditions are commonly seen by neuromuscular and musculoskeletal specialists. High-frequency diagnostic ultrasonography (US) has facilitated advances in the diagnosis and interventional management of wrist and hand disorders. US provides excellent soft tissue resolution, accessibility, portability, lack of ionizing radiation, and the ability to dynamically assess disorders and precisely guide interventional procedures. This article review the relevant anatomy, indications, and interventional techniques for common disorders of the wrist and hand, including radiocarpal joint arthritis, scaphotrapeziotrapezoidal joint arthritis, trapeziometacarpal joint arthritis, phalangeal joint arthritis, first dorsal compartment tenosynovitis, ganglion cysts, and stenosing tenosynovitis.
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Introduction
Tendon-related and joint-related disorders of the wrist and hand region are common clinical conditions that may result in significant functional limitations. When clinically indicated, precisely placed injections can facilitate the diagnosis and management of patients presenting with wrist and hand pain or dysfunction. During the past decade, Ultrasound (US) has emerged as an optimal modality for diagnostic and therapeutic injections about the wrist and hand region because of the superficial location of most wrist and hand targets. More recently, US-guided (USG) interventions have been used for the definitive surgical treatment of selected wrist and hand disorders. This article provides an overview of some of the common indications and techniques for USG procedures of tendon-related and joint-related disorders of the wrist and hand, including:
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Radiocarpal (RC) joint arthritis
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Scaphotrapeziotrapezoidal (STT) joint arthritis
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Trapeziometacarpal (TM) (first carpometacarpal [CMC]) joint arthritis
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Metacarpophalangeal (MCP) joint, proximal interphalangeal (PIP) joint, and distal interphalangeal (DIP) joint arthritis
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First dorsal compartment (DC) tenosynovitis (de Quervain syndrome)
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Ganglion cysts
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Stenosing tenosynovitis (trigger finger)
Key points for wrist and hand ultrasound-guided procedures
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The authors recommend the use of sterile technique with sterile probe covers and sterile gel, but multiple methods have been described to prevent infection during USG interventions.
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For the superficial structures in the wrist and hand, the authors recommend a high-frequency (>10 MHz) linear-array transducer. A small-footprint (hockey stick) transducer may be advantageous, but is not required.
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Although most procedures can be performed sitting or supine, the authors prefer supine positioning for patient comfort and ergonomics, as well as to reduce the risk of vasovagal episodes. Use of an arm board can further optimize positioning during USG procedures.
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Needle selection depends on procedure-specific and patient-specific factors, as well as operator preference. In general, using the smallest-gauge needle to accomplish the procedure minimizes patient discomfort.
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The type and amount of injectate are based on clinical indication, patient-specific factors, and clinician preference. Particulate corticosteroids are hyperechoic with US visualization, and thus may obscure the target when injected. Furthermore, larger particulate steroids may clog smaller-gauge needles.
Key points for wrist and hand ultrasound-guided procedures
- •
The authors recommend the use of sterile technique with sterile probe covers and sterile gel, but multiple methods have been described to prevent infection during USG interventions.
- •
For the superficial structures in the wrist and hand, the authors recommend a high-frequency (>10 MHz) linear-array transducer. A small-footprint (hockey stick) transducer may be advantageous, but is not required.
- •
Although most procedures can be performed sitting or supine, the authors prefer supine positioning for patient comfort and ergonomics, as well as to reduce the risk of vasovagal episodes. Use of an arm board can further optimize positioning during USG procedures.
- •
Needle selection depends on procedure-specific and patient-specific factors, as well as operator preference. In general, using the smallest-gauge needle to accomplish the procedure minimizes patient discomfort.
- •
The type and amount of injectate are based on clinical indication, patient-specific factors, and clinician preference. Particulate corticosteroids are hyperechoic with US visualization, and thus may obscure the target when injected. Furthermore, larger particulate steroids may clog smaller-gauge needles.
Radiocarpal joint
The RC joint is a synovial joint consisting of the articulation between the distal radius and the proximal carpal bones, and is supported by several ligaments and muscle-tendon units, as well as the triangular fibrocartilage complex. A variety of injuries may occur in the wrist, including dislocations, chronic instability, inflammatory arthritis, and osteoarthritis. For example, prior scaphoid fractures or scapholunate or lunotriquetral ligament injuries have been shown to predispose to STT joint arthritis.
The RC joint is best visualized using a high-frequency linear-array transducer placed dorsally over the distal radius in the anatomic sagittal plane with the wrist pronated and in slight flexion ( Fig. 1 ). Common pathologic findings on US include joint effusions, thickening of the synovium/synovitis, articular space narrowing, cortical irregularities, and osteophyte formation.
In patients who fail conservative management for the conditions discussed earlier, diagnostic and/or therapeutic injection of the RC joint may be considered. Furthermore, aspiration of effusion may be indicated as part of the diagnostic work-up for crystalline and inflammatory arthropathies. The reported accuracy rates of palpation-guided (PG) and USG injections into the wrist joint in the clinical setting range from 25% to 97% and 79% to 94% respectively.
Technique for ultrasound-guided radiocarpal joint injection
For injection of the RC joint, the patient is placed supine with the hand fully pronated and the wrist in slight flexion with the use of a towel (see Fig. 1 A). Placing the wrist in flexion opens the dorsal joint recess. The radioscaphoid (RS) joint is the preferred target when injecting the RC joint secondary to its ease of access and lack of significant overlying neurovascular structures. To localize the RS joint, a high-frequency linear-array transducer is placed in the anatomic axial plane over the dorsal wrist at the radial styloid. The transducer is then translated to place Lister’s tubercle in the center of the transducer. Following this, the RS joint is visualized by rotating the transducer 90° into the anatomic sagittal plane to produce a long-axis (LAX) view of the joint. The transducer may be slightly rotated to ensure that the needle trajectory is between the second and third extensor compartments, which are separated by Lister’s tubercle. This transducer orientation may result in the overlying tendons being oblique to the transducer. Although this results in cortical margins that are less conspicuous, the transducer position is optimized for the injection (see Fig. 1 ). Following localization, a 25-gauge 38-mm needle is inserted via an in-plane distal-to-proximal trajectory toward the articulation, using the distal radius as a bony backstop for the injection. The hypoechoic scaphoid cartilage may or may not be well visualized secondary to transducer orientation (see Fig. 1 B, [CR] ). With this technique, aspiration of an effusion in the wrist joint recess is also possible using a larger-gauge needle. Although not formally described in this article, the joint may alternatively be injected with the transducer in the same position as described earlier using an out-of-plane ulnar-to-radial or radial-to-ulnar trajectory.
Scaphotrapeziotrapezoidal joint
The STT joint is a dome-shaped articulation on the radial side of the wrist. The scaphoid is the most radial bone on the proximal carpal row and articulates with the distal radius, capitate, lunate, trapezium, and trapezoid. STT joint arthritis is the second most common pattern of wrist arthritis, observed in up to 15% of radiographic studies and 83.3% of cadaveric specimens.
The STT joint is best visualized sonographically using a high-frequency linear-array transducer placed over the palmar aspect of the wrist with the forearm supinated. The transducer is first placed parallel (LAX) to the first metacarpal, and then translated proximally until the TM joint and more proximal STT joint are visualized ( Fig. 2 ). Common pathologic US findings include joint effusions, synovitis/pannus, articular space narrowing, cortical irregularities, and osteophyte formation. The flexor carpi radialis (FCR) tendon lies anatomically just palmar and ulnar to the STT joint, and STT joint arthritis may result in FCR tendinopathies and/or tenosynovitis. Furthermore, there is often concomitant radiographic and possibly symptomatic TM joint arthritis. Consequently, it is prudent to consider associated pathologic conditions when performing interventional procedures about the STT joint.
In patients who have failed conservative management, such as rest, splitting, activity modification, and medications, injection of the STT joint for diagnostic or therapeutic purposes may be indicated. Smith and colleagues reported sonographically guided and PG injection accuracy rates of 100% and 80% respectively for the STT joint in a cadaveric model.
Technique for ultrasound-guided scaphotrapeziotrapezoidal joint injection
STT joint injections are accomplished via a palmar out-of-plane approach, with the patient’s wrist supinated and the transducer placed LAX over the first metacarpal (see Fig. 2 A). The STT joint is located by the method described previously, placing the joint in the center of the transducer. Care should be taken to identify the superficial radial artery, which courses adjacent to the palmar surface of the STT. Following this, a 25-gauge or 27-gauge 38-mm needle is inserted via an out-of-plane radial-to-ulnar approach using a walk-down technique (see Fig. 2 B, [CR] ). The small size of the joint space (usually 1 mL or less), necessitates consideration of injection goals before the procedure. Care must be taken to avoid injecting too much anesthetic into the joint space during the procedure, which may result in insufficient therapeutic injectate in the joint, or overdistention of the joint capsule, which may cause patient discomfort. Alternatively, this injection can be performed via an in-plane radial-to-ulnar approach, with the transducer in the anatomic axial plane.
Trapeziometacarpal (first carpometacarpal) joint
The TM joint, also known as the first CMC joint, is the articulation between the first metacarpal and the trapezium, and is crucial for normal thumb mobility. There are several key surrounding structures that need to be taken into consideration when performing TM joint procedures. The superficial radial nerve is located on the radial side of the wrist, and has terminal branches coursing along either side of the TM joint. The radial artery branches into superficial and deep palmar arteries at the anatomic snuffbox just proximal to the TM joint, and its location should be noted before any interventional procedures.
The TM joint is the second most common site affected by idiopathic arthritis in the hand, often resulting in a box deformity as well as pain with grasping and fine manipulation. There can be a normal step-off representing radial protrusion of the metacarpal base, which is often accentuated in the setting of arthritis. Patients with arthritic changes may also have associated ligamentous laxity.
The TM joint is best visualized using a high-frequency linear-array transducer or small-footprint hockey-stick transducer placed radially over the first metacarpal in the anatomic coronal plane. The transducer is translated proximally until the TM joint is visualized. When static imaging is suboptimal, passive thumb motion reveals the joint margins. Common US findings of TM joint disorder include joint effusion, synovitis/pannus, articular space narrowing, cortical irregularities, radial subluxation, and osteophyte formation. For patients with pain that is refractory to conservative management, such as thumb spica, rest, nonsteroidal antiinflammatory drugs (NSAIDs), and occupational therapy, diagnostic or therapeutic injection may be considered. PG injections of the TM joint have been reported to be accurate in 0% to 97% of patients, whereas USG and fluoroscopically guided injections have reported accuracy rates of 94% to 100%.
Technique for ultrasound-guided trapeziometacarpal (first carpometacarpal) joint injection
The patient is positioned with the forearm in the neutral position ( Fig. 3 A). The injection is performed by first locating the TM joint via the method described earlier and placing the center of the TM joint in the middle of the transducer. A 25-gauge to 27-gauge 32-mm needle is then advanced into the joint using an out-of-plane dorsal-to-palmar approach and a walk-down technique (see Fig. 3 , [CR] ). Occasionally, anatomic and pathologic variability may necessitate an out-of-plane palmar-to-dorsal approach or even an in-plane proximal-to-distal or distal-to-proximal approach using a gel standoff. Be aware that using a palmar-to-dorsal approach can result in increased patient discomfort caused by the increased sensitivity of the thenar eminence. Care should be taken to avoid the aforementioned neurovascular structures located within the vicinity of the joint. In addition, clinicians should avoid injecting excessive anesthetic into the joint space during the procedure, which may result in insufficient therapeutic injectate in the joint or overdistention of the joint capsule. In cases of severe osteoarthritis, manipulation of the thumb into a more adducted position may help facilitate a successful injection.
Metacarpophalangeal, interphalangeal, proximal interphalangeal, and distal interphalangeal joints
The MCP joints represent the attachments between the metacarpal bones and the proximal phalanges. The proximal interphalangeal (PIP) and DIP joints are the two most distal joints of the hand. The PIP joint connects the proximal and middle phalanx, whereas the DIP joint connects middle and distal phalanx. The thumb is composed of only an interphalangeal (IP) joint and has no middle phalanx. The MCP and IP (PIP, DIP, and thumb IP) joints are stabilized by the collateral ligaments and the flexor-extensor tendons, which are bordered ulnarly and radially by the digital neurovascular bundles.
The MCP and IP joints are the most common joints to be affected by disorders in the hand. Dislocations, sprains, fractures, primary and posttraumatic osteoarthritis, and inflammatory arthropathies are common. These conditions result in pain and dysfunction affecting activities of daily living and occupation in many individuals.
The MCP and IP joints are best viewed using a high-frequency linear-array transducer or small-footprint hockey-stick transducer. Gel standoffs may be used as necessary to optimize visualization. Common pathologic findings include joint effusion, joint erosions, cortical irregularities, synovial thickening/pannus, synovial cysts, articular space narrowing, periarticular ganglia, and osteophyte formation.
In patients who have failed conservative management such as paraffin baths, occupational therapy, relative rest, activity modification, and NSAIDs, therapeutic or diagnostic injection may be indicated. Literature regarding accuracy rates for PG and USG injections of the smaller joints of the hand (MCP, IP, DIP, and PIP joints) has reported accuracy rates of 0% to 97% and 94% to 100% respectively.
Technique for ultrasound-guided metacarpophalangeal, interphalangeal, proximal interphalangeal, and distal interphalangeal joint injections
The dorsal recesses typically provide the easiest access to the MCP and IP joints. For the dorsal out-of-plane approach, the patient’s forearm is pronated and placed over a rolled towel to facilitate finger flexion ( Fig. 4 A). A high-frequency, ideally small-footprint, linear-array transducer is aligned LAX to the phalanges with the target joint placed in the center of the transducer. A 25-gauge or 27-gauge 25-mm needle is inserted via out-of-plane in either an ulnar-to-radial or radial-to-ulnar direction (depending on accessibility) and advanced into the joint space. The amount of injectate is usually small (1 mL or less), because overdistention of the joint capsule usually results in postprocedural pain. Alternatively, an in-plane proximal-to-distal, radial-to-ulnar, or ulnar-to-radial approach to the joint may be used, depending on preference and anatomy.
First dorsal compartment of the wrist
The first DC of the wrist contains the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons and is anatomically located just radial to the radial styloid. The Lister tubercle at the distal radius separates the second DC (containing the extensor carpi radialis longus and brevis tendons) from the third DC (containing the extensor pollicis longus tendon), is easily palpated, and can serve as a landmark for identifying the first to third DCs. The location of the superficial radial nerve, which travels from palmar to dorsal just proximal to the radial styloid, should be identified before any procedure involving the first DC because it has a variable branching pattern and may be within the planned needle trajectory. The radial artery divides into its superficial and deep branches just deep to the first DC.
First DC stenosing tenosynovitis (de Quervain syndrome) is the most common tendinopathy affecting the wrist and hand. The pathophysiology is thought to involve repetitive microtrauma of the first DC, often occupationally or recreationally related, resulting in degenerative and inflammatory changes to the APL and EPB tendons at the level of or just distal to the radial styloid. De Quervain syndrome is more common in diabetics and patients with inflammatory arthropathies such as rheumatoid arthritis. De Quervain syndrome typically presents as pain and tenderness over the radial styloid, with pain exacerbated by wrist and thumb movements, particularly ulnar deviation. On physical examination, symptoms can be reproduced with the Finkelstein test (ulnar deviation with the thumb adducted).
The first DC, similar to other superficial structures of the hand, is best viewed using a high-frequency linear-array transducer. The first DC can be identified by placing the wrist in a neutral position and first placing the transducer over the Lister tubercle in the anatomic axial plane to identify the second DC. The transducer is then translated radially along the continuous cortical margin of the radius to identify the first DC tendons lying on the radial aspect of the distal radius. From here, the APL and EPB tendons can be traced proximally to their proximal intersection with the second DC tendons in the dorsal forearm (the site of proximal intersection syndrome) or distally to their insertions.
Common sonographic findings of first DC stenosing tenosynovitis include tendon and synovial sheath thickening, distension of the tendon sheath with anechoic fluid surrounding the tendon, and peritendinous hyperemia on low-flow color Doppler ( Fig. 5 B). Note that tenosynovial fluid may not be seen at the level of the retinaculum, but more distal because it is likely to flow to regions of less resistance. Conservative management includes occupational therapy, workspace/activity modifications, rest, oral and topical NSAIDs, and splinting/bracing.
