Evaluation and Management of Carpal Instability

Current Physical Medicine and Rehabilitation Reports https://doi.org/10.1007/s40141-023-00400-y Evaluation and Management of Carpal Instability Ryan Wei1,2 · James E. Gardner3 · Stephen Schaaf3,4 · J. Bradford Hill5 · Zachary Bailowitz2,6 Accepted: 17 April 2023 © The Author(s) 2023 Abstract Purpose of Review This paper sets out to review the past and current literature on the evaluation and management of the various types of carpal instability. Recent Findings Carpal instability has many sub-types, and therefore, its evaluation and management widely differ. There are recent studies that indicate that while MRI and MR arthrography are the mainstays for evaluation, certain CT and radiographic measurements may be better at diagnosing scapholunate ligament tears. In addition, recent research has proposed multiple sonographic protocols in the evaluation of carpal ligament pathology. However, the comparison of ultrasound to other imaging modalities is limited. The research for operative and non-operative management of carpal instability is limited and often guided by expert opinion. To date, no studies exist on the use of novel injection techniques to treat carpal instability. Summary Evaluation of carpal instability is evolving, and ultrasound may play an increased role. Evidence regarding nonoperative management of carpal instability is limited. Keywords Carpal instability · Scapholunate · Wrist pain · Wrist instability Introduction * Zachary Bailowitz Ryan Wei James E. Gardner Stephen Schaaf J. Bradford Hill 1 Department of Family and Community Medicine, University of California San Francisco, San Francisco, CA, USA 2 Department of Orthopedic Surgery, University of California San Francisco, San Francisco, CA, USA 3 Department of Physical Medicine and Rehabilitation, Vanderbilt University Medical Center, Nashville, TN, USA 4 Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, TN, USA 5 Department of Plastic Surgery, Vanderbilt University Medical Center, Nashville, TN, USA 6 Department of Orthopedics, Podiatry, & Sports Medicine, Kaiser Permanente Oakland Medical Center, Kaiser Permanente, 3600 Broadway, Oakland, CA 94611, USA Carpal instability is an important cause of acute and chronic wrist pain and can lead to long-term dysfunction if not managed appropriately. Carpal instability is caused by the disruption of key ligaments or articular geometry from either fractures, chronic repetitive overuse injuries, or less commonly rheumatological conditions [1]. If these are unaddressed, ligamentous laxity and instability can ensue. Injury patterns are commonly from sportsrelated hand or wrist injuries, acute trauma, and occupational activities typically stemming from a fall on an outstretched hand [2]. In sports, it has been reported that up to 25% of injuries involve the hand and wrist [3]. Recognizing, diagnosing, and treating these injuries early is key to the prevention of long-term disability [4]. While certain instability patterns require surgical attention, there is a paucity of literature regarding non-operative options. This review focuses on the pathoanatomy, evaluation, and treatment of carpal instability, with special attention paid to recent studies regarding non-operative indications and treatment. Anatomy The wrist is composed of eight carpal bones that abut the radius and ulna. The bones are arranged into proximal and distal rows. The proximal consists of the scaphoid, lunate, 13 Vol.:(0123456789) Current Physical Medicine and Rehabilitation Reports and triquetrum, with the hamate, capitate, trapezoid, and trapezium in the distal row, and the pisiform, a sesamoid bone, sitting palmar to the triquetrum within the flexor carpi ulnaris tendon [5]. The proximal row is mobile as it conforms to the radius and ulna while the distal row is rigid and functions to articulate with the metacarpals [5]. The rows are stabilized by interosseous ligaments and secondary stabilizers known as the capsular ligaments, consisting of the “proximal palmar V” and the “dorsal V” groups (Fig. 1) [6]. Typically, the interosseous, or intrinsic, ligaments originate and insert between carpal bones, whereas the extrinsic ligaments connect the carpal bones to the radius and ulna. Attachments and functions of the extrinsic ligaments are beyond the scope of this review; however, it is important to note that disruption of both intrinsic and extrinsic ligaments simultaneously result in instability visible at rest without dynamic motion, while sole intrinsic ligament disruption may not initially be apparent without stress or dynamic imaging [7]. The most common ligament injuries resulting in carpal instability clinically involve the scapholunate interosseous ligament (SLIL) and lunotriquetral interosseous ligament (LTIL), with the latter being less frequently injured [7]. These two ligaments have three bands, the dorsal, central, and volar, with the dorsal band being the most robust and primary stabilizer for the SLIL and the volar being important for rotational stability [7]. Thus, disruption of the dorsal band of the SLIL enables dorsal intercalated segment instability (DISI), and the disruption of the volar band of the LTIL creates volar intercalated segment instability (VISI) which will be further discussed in a subsequent Fig. 1  Schematic display of intracapsular carpal ligaments. a Palmar “V” ligaments. The proximal palmar “V” consists of the palmar radiolunotriquetral ligament (pRLTL) on the radial side and the ulnolunate (ULL) and ulnotriquetral ligaments (UTL) on the ulnar side. The radial leg of the distal palmar “V” is formed by the radioscaphocapitate (RSCL) and scaphocapitate ligament (SCL), while the triquetro- 13 section [7]. Additionally, the wrist anatomy is further characterized by the arcs of Gilula, which are helpful in the evaluation of wrist anatomy on radiography and suggestive of wrist injury when they are disrupted. The first arc traces the proximal surface of the proximal row at the articulation with the radius and ulna. The second arc follows the distal surface of the proximal row at its articulation with the distal row. Finally, the third arc traces the proximal surface of the distal row [8]. Carpal Instability Patterns Carpal instability has been classically divided into four patterns of injury based on the Mayo classification: 1. 2. 3. 4. Carpal instability dissociative (CID) Carpal instability non-dissociative (CIND) Carpal instability complex (CIC) Carpal instability adaptive (CIA) [9]. CID: DISI and VISI CID refers to an instability pattern within the proximal row of carpal bones. These injuries typically result from hyperextension or hyperpronation injuries [9]. In general, the scaphoid has a tendency to flex while the triquetrum has a tendency to extend. When both the SLIL and LTIL are intact, this results in a neutral lunate. However, if one of these ligaments is disrupted, the force from the other i (...truncated)