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Carpal Bone Pathology and Instability

Carpal instability and bone pathology, including SLAC wrist, Kienböck's disease, and CIND, with a focus on ligamentous dissociation and osteonecrosis.

121 citationsUpdated Oct 2026

Overview

Carpal instability encompasses a spectrum of pathologies where no single classification system is both exhaustive and simple enough for universal clinical application [2]. The Larsen analytic system characterizes instability across six categories—chronicity, constancy, etiology, location, direction, and pattern—with the first three serving as key prognostic factors [2]. Despite this framework, a generally agreed analysis that unifies diagnosis, treatment guidelines, and outcome reporting remains lacking [3]. Instability patterns are broadly divided into dissociative (CID), involving predominant dysfunction between bones of the same carpal row, most commonly between the scaphoid and lunate [2], and nondissociative (CIND), which includes radiocarpal, midcarpal, and combined instabilities [2]. Specific deformity patterns include dorsal intercalated segment instability (DISI) and volar intercalated segment instability (VISI), defined by abnormal dorsal or volar rotation of the lunate and triquetrum, respectively [2].

Diagnosis relies heavily on computed radiography to evaluate carpal bone relationships in dislocation or instability [13]. Arthroscopic portals developed via an inside-out method are safe and useful for ligament or bony intracarpal repairs [75]. The primary goals of treatment are stabilization of carpal bones and maintenance of reasonable mobility, which can usually be achieved by techniques other than arthrodesis [6]. Early diagnosis and management of perilunate dislocation are necessary to prevent major sequelae such as instability and carpal bone necrosis [1]. However, the ideal treatment for scapholunate instability remains unresolved due to inconsistent results and ongoing concerns regarding complications [27]. There is a lack of objective evidence on long-term outcomes for the unstable wrist, necessitating collaborative working and referral to specialized centers for randomized controlled trials [40].

Specific procedural findings indicate that modified Brunelli tenodesis for static scapholunate instability resulted in arthritic changes in only 1 of 8 cases over 10 years [4]. Dorsal intercarpal ligament capsulodesis for chronic scapholunate instability resulted in early arthritic degeneration due to ongoing instability, but most patients had acceptable long-term function [5]. Arthroscopic thermal capsulorrhaphy for palmar midcarpal instability resulted in improvement or resolution of instability in all wrists [11]. Replacement of the lunate with a costal cartilage graft for advanced Kienböck disease showed absence of carpal collapse and good functional results, though follow-up was short [12]. Anatomical anterior and posterior reconstruction for scapholunate dissociation resulted in no patient requiring secondary surgery or treatment related to carpal stabilization [21]. Intercarpal arthrodesis successfully treated chronic carpal instability resulting from trauma in a retrospective review of five patients [23]. Distal scaphoid resection for arthritis secondary to scaphoid nonunion is a durable procedure with good long-term results, with 94% of patients remaining satisfied and no further wrist collapse or radiocarpal arthritis developing [26]. Dorsal intercarpal augmentation ligamentoplasty offers potential advantages for treating subacute and chronic flexible carpal instabilities associated with scapholunate dissociation [44]. Aggressive surgery for carpal dislocation presenting after a delay of up to six months is not justified [46]. Proximal row carpectomy is not recommended for the management of scapholunate dissociation in the absence of degenerative changes due to disappointing results compared to other treatments [67]. Contraindications for primary repair of the scapholunate ligament include degenerative arthritic changes, unreducible dissociation, inadequate scapholunate interosseous ligament tissue, and other carpal ligamentous disruptions or fractures [68]. Carpal-sparing surgery such as radial shortening osteotomy provides very good and lasting clinical results in Kienböck disease with carpal collapse [79]. Excisional arthroplasty is highly recommended for idiopathic, symptomatic, isolated scaphotrapeziotrapezoidal osteoarthritis without midcarpal instability [86]. Correct diagnosis and proper surgical indications are necessary to reduce the number and enhance the efficacy of operations required to treat carpal boss [38].

Anatomy & Pathophysiology

Bony Anatomy and Kinematics

The carpus comprises two rows of eight bones bridging the forearm and hand, providing wrist movement while retaining stability [50]. The proximal row includes the scaphoid, lunate, and triquetrum, which function as an intercalated segment between the forearm and the distal row [50]. The distal row consists of the trapezium, trapezoid, capitate, and hamate [50]. The pisiform is a sesamoid bone enclosed within the flexor carpi ulnaris tendon sheath and is not theoretically considered part of the proximal carpal row [50]. The distal carpal row is rigid with little intercarpal motion due to stout ligaments, acting as a functional unit [47]. The scaphoid bridges both the proximal and distal carpal rows [47]. The capitate and hamate exhibit only 2 degrees of intercarpal rotation and less than 2 mm of proximal-distal translation [108].

Kinematically, approximately 62° of wrist extension occurs through the radiocarpal joint, while 62% of wrist flexion occurs through the midcarpal joint [47]. The midcarpal joint is primarily responsible for 20° of radial deviation and 40° of ulnar deviation [47]. In normal wrists, motion occurs equally at the midcarpal and radiocarpal joints [113]. The dart-thrower's motion occurs almost exclusively through the midcarpal joint, defining the transition between flexion and extension of the scaphoid and lunate [48]. The scaphoid rotates 35 degrees more than the lunate to reach the limits of flexion-extension due to the lunate's longer radius of curvature [104]. During wrist flexion from neutral, the proximal row translates dorsally, whereas during extension from neutral, it translates palmarly [47].

Ligamentous Anatomy

Extrinsic carpal ligaments connect the radius or ulna to the carpus, with volar ligaments generally stronger than dorsal ligaments [47]. The radioscaphocapitate (RSC) ligament connects to the scaphoid waist and limits ulnar translation of the carpus [47]. The long radiolunate ligament helps limit ulnar translocation, while the short radiolunate ligament controls lunate position [47]. The radioscapholunate ligament (ligament of Testut) is a vascular conduit rather than a true ligament [47]. The dorsal radiocarpal ligament (DRC) has a trapezoidal shape, passing from the dorsal rim of the distal radius to the lunate and triquetrum [47].

The scapholunate interosseous ligament (SLIL) is the major wrist stabilizer and the most commonly injured wrist ligament [47]. It is C-shaped, consisting of dorsal, palmar, and interosseous portions, with the dorsal portion being the strongest and thickest [47]. The SLIL provides a flexion force on the lunate given its attachment to the scaphoid [47]. Specifically, the SLIL comprises a proximal or membranous portion with no significant strength, a dorsal portion that is the strongest and prevents translation, and a palmar portion that acts as a rotational constraint [64]. The radioscapholunate ligament provides little mechanical stability [64]. The palmar stabilizers of the scaphoid include the RSC ligament, long radiolunate ligament, and short radiolunate ligament, which are secondary stabilizers [64]. The dorsal stabilizers of the scaphoid are the dorsal radiocarpal ligament and the dorsal intercarpal ligament [64].

The lunotriquetral interosseous ligament (LTIL) is C-shaped, with the volar portion being the thickest and strongest [47]. The LTIL provides an extension moment on the lunate given its attachment to the triquetrum [47]. The dorsal intercarpal ligament (DIC) passes from the dorsal tubercle of the triquetrum to the distal pole of the scaphoid [47]. The DIC reinforces the elastic dorsal wrist capsule and helps stabilize the scapholunate articulation, contributing to the dorsal SLIL via its deep fibers [47]. The dorsal scaphotriquetral (DST) ligament spans the dorsal-distal rims of the scaphoid, lunate, and triquetrum [108]. The DST ligament represents both a robust attachment of the transverse fibers of the DIC to each bone of the proximal carpal row and a labral extension of the interosseous SL and LT ligaments across the dorsal base of the capitate [108]. The dorsal capsuloligamentous scapholunate septum (DCSS) is a fibrous capsular structure originating from the deep surface of the intracapsular DIC and inserting on the dSLIL, acting as an additional stabilizer of the SL joint [108]. There are no ligaments, palmar or dorsal, between the lunate and capitate [108].

The midcarpal joint is crossed by four additional palmar intercarpal ligaments: palmar triquetrohamate, triquetrocapitate, scaphocapitate, and radiopalmar STT ligament [108]. The palmar triquetrohamate and triquetrocapitate ligaments play an important role in midcarpal joint stabilization [108]. The strong ligamentous attachments of the scaphoid to the distal carpal row are important stabilizers of the proximal carpal row [108]. Disruption of these scaphoid attachments has been associated with both dissociative and nondissociative instability patterns of the proximal carpal row [108]. The space of Poirier is an area adjacent to the proximal capitate without ligamentous attachment, situated ulnar to the RSC ligament and radial to the long radiolunate in the floor of the carpal tunnel [47]. This space is a weak area vulnerable to instability where the distal carpal row separates from the lunate during a perilunate dislocation [47].

Vascular Anatomy

The vascular supply of most carpal bones enters the distal half, leaving the proximal half at risk of avascular necrosis [109]. The scaphoid and capitate are each supplied by a single vessel, increasing their risk of avascular necrosis [109]. Approximately 20% of all lunates are supplied by a single vessel, increasing their risk of avascular necrosis [109]. The trapezium, triquetrum, pisiform, and 80% of lunates receive nutrient arteries through two nonarticular surfaces and have consistent intraosseous anastomoses, reducing the risk of avascular necrosis [109]. The trapezoid and 50% of hamates lack an intraosseous anastomosis and are at risk of avascular fragments [109]. The dorsal branch of the radial artery supplies 70–80% of the scaphoid proximally [109]. There are no perforators at the waist, cartilage, or SL ligament of the scaphoid [109].

Pathophysiology and Instability Mechanisms

Carpal instability is defined as the inability of the wrist to maintain anatomic relationships under normal loads [7]. A wrist joint is biomechanically unstable when it cannot bear loads and does not exhibit normal kinematics throughout its arc of motion [89]. Stability implies the ability to transfer functional loads without yielding or losing internal joint congruency and the capacity to maintain motion without sudden alterations of intercarpal alignment [66]. Ligament injury, wrist instability, and carpal malalignment are independent events; the presence of one does not necessarily imply the presence of the other two [33]. Not all wrists with a ligament injury develop carpal instability, and not all unstable wrists are malaligned [33]. Carpal instability signifies the disappearance of the balance between extrinsic and intrinsic forces that maintains joint cohesion [167].

Carpal instability usually follows a high-energy injury leading to hyperextension, ulnar deviation, and intercarpal supination [43]. This mechanism can lead to an interruption of the oval ring, commonly in the proximal carpal row, leading to instability [43]. The most common pattern of injury associated with this mechanism is a perilunate dislocation or fracture-dislocation [43]. Progressive perilunate instability describes the global pattern of injury propagation centered on the lunate [7]. Mayfield described four stages of progressive perilunate instability starting with scapholunate ligament disruption [64].

Stage I involves SL dissociation or scaphoid fracture [16]. In this stage, the distal carpal row is forced into hyperextension, creating a progressive extension moment to the scaphoid transmitted to the lunate via SL ligaments [76]. The lunate is tightly constrained by the long and short radiolunate ligaments during Stage I [76]. Progressive tearing of the SL interosseous membrane and ligaments occurs from palmar to dorsal, eventually leading to complete SL dissociation [76].

Stage II involves lunocapitate dislocation [16]. Once the SL joint is disrupted or the scaphoid fractured, the distal row may translate dorsally and dislocate relative to the lunate [76]. A curved capsular rent across the space of Poirier appears as a consequence of Stage II dislocation [76].

Stage III involves lunotriquetral disruption and/or triquetrum fracture [16]. As the capitate displaces dorsally, the triquetrohamate ligamentous complex becomes tensed, creating an extension moment and dorsal translation vector to the triquetrum [76]. Stage III results in separation of the triquetrum from the lunate secondary to rupture of LT ligaments or a sagittal fracture of the triquetrum [76].

Stage IV involves lunate dislocation from the lunate fossa [16]. When all perilunate ligaments are torn, the dorsally displaced capitate may exert a palmar translation force to the dorsum of the lunate, resulting in a palmar lunate extrusion [76]. The short radiolunate ligament remains intact during lunate dislocation in Stage IV [16].

Dorsal intercalated segment instability (DISI) is the most common form of carpal instability [19]. DISI is characterized by the lunate and triquetrum tilting dorsally [19]. DISI is caused by SL ligament disruption [19]. The dorsal fibers of the SL ligament are stronger than the volar fibers [19]. DISI develops after secondary injury to stabilizing dorsal and/or volar extrinsic ligaments and volar scaphotrapeziotrapezoid (STT) ligaments [19]. The mechanism of DISI involves scaphoid hyperflexion and lunate hyperextension [19].

Volar intercalated segment instability (VISI) is the second most common form of carpal instability [19]. VISI is characterized by the lunate and scaphoid tilting volarly [19]. VISI is caused by disruption of the LT interosseous ligament [19]. VISI can be a normal variant with generalized ligamentous laxity [16]. VISI can be caused by disruption of the LTIL, DRC ligament injury, volar radiolunate ligament injury, rheumatoid arthritis, and possibly crystalline arthropathies [16]. VISI results in lunate flexion with metacarpal extension secondary to SLIL attachment [16].

Ulnar translocation involves the entire proximal row being displaced ulnarly [16]. Ulnar translocation is seen commonly in rheumatoid arthritis, Madelung deformity, and after injury to the RSC ligament [16]. Dorsal translocation involves the proximal row being displaced dorsally [16]. Dorsal translocation commonly results from a malunited distal radius fracture with residual dorsal angulation [16].

Carpal instability dissociative (CID) is instability between bones of the same carpal row [19]. CID includes scapholunate dissociation and lunotriquetral dissociation [19]. Carpal instability nondissociative (CIND) is instability between carpal rows, such as midcarpal or radiocarpal instability [19]. Carpal instability adaptive (CIA) is carpal instability resulting from a malunited distal radius fracture [19]. Carpal instability complex (CIC) includes perilunate dislocations that combine CID and CIND [19].

SLD is the most frequent carpal instability [32]. SLD can appear as an isolated injury or in association with other local injuries such as distal radial fractures, perilunate injuries, displaced scaphoid fractures, or inflammatory arthritis [32]. If only the palmar SL ligament and the proximal membrane are ruptured, minor kinematic alterations may occur in scaphoid flexion or lunate extension during wrist motion [32]. Partial SL ligament injuries result in "dynamic" or "occult" instability with no diastasis of the SL interval or resting postural changes of the carpus [32]. Complete sectioning of the SL ligaments does not acutely result in SL diastasis or carpal malalignment [32]. Immediate carpal postural changes occur only if there is concomitant rupture of critical ligament stabilizers of the proximal carpal row, including the radiopalmar STT ligament complex, dorsal intercarpal ligament, or long RL ligament [32].

The unconstrained lunate has a natural tendency toward displacing into extension owing to its shape and articulation with a volarly inclined radial surface [32]. Without its proximal tether to the lunate, the scaphoid flexes around the RSC ligament while pronating and translocating dorsally and radially under flexion loads [32]. With slackening or attenuation of the long RL or DIC ligaments, the triquetrum and lunate rotate dorsally under the extension moment of the hamate’s articular surface [32]. Increased compressive and shear stress appears on the dorsal and lateral aspect of the radioscaphoid articulation as the proximal pole of the scaphoid subluxates dorsoradially with wrist flexion [32]. The lunate extends but its kinetics remain stable because the lunate and the lunate facet of the radius are perfectly congruent [32]. The radiolunate articular cartilage is spared until very late in the degenerative process following SLD [32].

Scapholunate advanced collapse (SLAC) is a three-stage progression of degenerative changes secondary to SLD [32]. In Stage I of SLAC, only the distal radial styloid-scaphoid articular surface degenerates, with characteristic breaking of the styloid tip [32]. In Stage II of SLAC, progressive loss of the proximal scaphoid articular cartilage and the dorsal scaphoid fossa ensues [32]. In Stage III of SLAC, the midcarpal joint degenerates [32]. Neglected scaphoid nonunion is associated with osteonecrosis and progressive radiocarpal and midcarpal arthritis, a condition called scaphoid nonunion advanced collapse (SNAC) [10]. An unstable scaphoid nonunion requires bone grafting to restore height and correct carpal malalignment, principally dorsal intercalated segment instability [10].

Fragmentation of the lunate in Kienböck disease results in loss of mechanical strength of the central column and proximal migration of the capitate [146]. Proximal migration of the capitate slackens the RSC and SC ligaments and leads to kinematic disruption of the carpus [146]. The loaded scaphoid in Kienböck disease is apt to progressively collapse into flexion, an example of adaptive carpal instability [146]. Kienböck disease rarely demonstrates SL gap, DISI, or dorsal translation of the scaphoid [146]. Division of the dorsal or palmar part of the intrinsic LT ligament can cause significant kinematic dysfunction and a dynamic VISI deformity [73]. Division of extrinsic ligaments can result in a highly dysfunctional static VISI deformity [73]. The triquetrum is recognized as a keystone of ulnar carpal motion as it connects to both the lunate and the distal carpal row [73]. The triquetrum and its ligaments are regarded as key elements in providing proprioceptive information for neuromuscular wrist stabilization [73]. The severity of carpal instability is directly correlated [167].

Classification

General Principles and Limitations

The controversy regarding which carpal instability classification is best is considered meaningless because no system can be ideal [2]. The complex nature of the wrist has hampered the ability to formulate concise, yet thorough, algorithmic approaches to evaluation and treatment [56]. The row theory more clearly accounts for the function of the wrist than the column theory [63].

Larsen Analytic System

Larsen: Larsen and colleagues devised a six-category analytic system to help clinicians assess patients with carpal instability [2]. The six categories are chronicity, constancy, etiology, location, direction, and pattern [2]. The first three categories (chronicity, constancy, etiology) are prognostic [2]. The fourth and fifth categories (location, direction) are radiographic [2]. The sixth category (pattern) is descriptive [2].

Chronicity refers to the expected outcome of the pathologic condition, defining acute as having ligament healing potential, subacute as having limited healing potential without arthritis or fixed deformity, and chronic as having no healing potential with associated arthritis or fixed deformity [31]. Constancy refers to whether the instability pattern is static (apparent on routine PA and lateral views) or dynamic (detected only with fluoroscopic views or stress maneuvers) [31]. The Larsen analytic system is not fully inclusive and has not been readily incorporated into clinical outcome studies [2]. It is not possible to categorize a patient with chronic reducible dissociative DISI pattern with dorsal scaphoid translation into a single location category such as proximal intercarpal, radiocarpal, or midcarpal because all three joints and their corresponding ligaments are involved [2].

Instability Patterns (CID, CIND, CIC, CIA)

Carpal Instability Dissociative (CID): CID occurs when the predominant dysfunction occurs between bones of the same carpal row [2]. Most CIDs occur between the scaphoid and lunate, and less often between the lunate and triquetrum [2]. Dissociative instabilities seldom occur between the bones of the distal carpal row due to little mobility between them [2]. According to the Mayo Clinic classification, complete rupture of ligaments binding bones of the same row fulfills the criteria of a CID [82].

Carpal Instability Nondissociative (CIND): If the proximal carpal row as a unit collapses and becomes unstable in flexion or extension, this is termed nondissociative instability of the proximal carpal row or proximal row instability [2]. If carpal disruption preserves ligaments connecting bones of the same row but not those stabilizing radiocarpal and/or midcarpal ligaments, it fulfills the criteria of a CIND [82]. A severe, posttraumatic variety of CIND has been described associated with acute fractures of the radius or scaphoid [2].

Complex Instability of the Carpus (CIC): When a carpal injury shares features of both CID and CIND, it is categorized as a complex instability of the carpus (CIC) [82]. Acute carpal fracture-dislocations are examples of CIC [82]. Chronic unreduced fracture-dislocations should not be classified as a carpal instability problem but as a complex injury that tends to progress to stiffness and degenerative disease [82].

Dislocations: There are six types of wrist dislocations: dorsal perilunate dislocations, dorsal perilunate fracture-dislocations, palmar perilunate dislocations, radiocarpal dislocations, axial dislocations, and isolated carpal bone dislocations [82]. Dorsal perilunate dislocations and dorsal perilunate fracture-dislocations share a carpal dislocation occurring around the lunate [82]. Palmar perilunate dislocations result from a mechanism producing palmar displacement of the distal row relative to the lunate [82]. Radiocarpal, axial, and isolated carpal bone dislocations are nonperilunate dislocations usually resulting from high-energy trauma [82]. If the entire carpus is translocated with respect to the radius in any direction, this is classified as radiocarpal instability [2].

Midcarpal Instability

Midcarpal Instability: Midcarpal instability is a collective term for conditions where wrist instability is predominantly between the proximal and distal carpal rows [18]. Palmar midcarpal instability is the most common type of midcarpal instability [18]. Midcarpal instability represents multiple distinct entities involving abnormal force transmission across the midcarpal joint [169]. There is a lack of unanimity regarding the etiology, terminology, and treatment of midcarpal instability [81]. The authors of a 2022 letter propose that the term midcarpal instability be subclassified into traumatic and nontraumatic categories because the pathology often involves dissociative ligament disruptions rather than being truly nondissociative [160].

Malalignment Patterns (DISI/VISI)

DISI/VISI: Dorsal intercalated segment instability (DISI) and volar intercalated segment instability (VISI) are the two major patterns of sagittal malalignment [2]. In DISI, the lunate and triquetrum rotate abnormally in a dorsal direction [2]. In VISI, the lunate and triquetrum rotate abnormally in a volar direction [2]. Dorsal intercalated segment instability (DISI) is more common than volar intercalated segment instability (VISI) [7].

Specific Condition Classifications

SNAC/SLAC: Differentiation between SNAC-wrist and SLAC-wrist is important for classification and preoperative planning in the treatment of advanced carpal collapse [147].

Lichtman: The Lichtman classification for Kienböck disease has substantial interobserver reliability with a coefficient of 0.63 [196]. Stage 3A of the Lichtman classification for Kienböck disease was less reliably identified with an interobserver reliability coefficient of 0.38 [196]. A modification of the Lichtman classification using a radioscaphoid angle of 60° to subdivide stage 3 increased overall interobserver reliability to 0.81 and stage 3A reliability to 0.75 [196]. A classification-based treatment algorithm for Kienböck disease reexamines current classification systems to account for contemporary findings including vascular and cartilaginous manifestations [162].

Scapholunate Dissociation: A new classification system for scapholunate dissociation has been proposed that is simple, reproducible, and precise regarding the topography of the lesion on the scapholunate ligament [174].

Clinical Presentation

History and Mechanism of Injury

Patients with carpal injury commonly present with wrist pain as the primary complaint [36]. In the acute phase, pain, swelling, and ecchymosis around the carpus may be present [36]. Carpal instability is characterized by wrist pain, loss of motion, and weakness [19]. Lack of treatment for carpal instability may lead to degenerative arthritis and disability [19]. Early diagnosis and management of perilunate luxation are necessary to prevent major sequelae such as instability and carpal bone necrosis [1]. Early accurate diagnosis of intrinsic carpal ligament injuries provides for best outcomes, while delayed diagnosis leads to arthritis within 10 years if not treated [42].

Carpal instability usually follows a high-energy injury leading to the wrist undergoing a force associated with hyperextension, ulnar deviation, and intercarpal supination [43]. A fall on the outstretched hand with the wrist in extension, ulnar deviation, and intercarpal supination may cause a wide spectrum of injuries, from minor scapholunate sprains to complete perilunate dislocations [32]. Radiocarpal instability may occur acutely, develop gradually, or be observed as a late sequela of a perilunate dislocation [51]. In the acute phase of radiocarpal instability, patients frequently complain of wrist swelling, deformity, and pain [51]. Dorsal wrist swelling and tenderness in radiocarpal instability are most noticeable at the radiocarpal level and are aggravated by wrist motion [51]. Deformity in radiocarpal instability may be due to an ulnar, dorsal, or palmar translation of the carpus [51]. Most patients with radiocarpal instability sustain an associated injury, with disruption to the ipsilateral distal radioulnar joint being common [51]. Patients with palmar midcarpal instability may have significant disability that may be refractory to nonsurgical management [41].

Physical Examination: General Findings

The most constant and dependable sign of carpal injury is well-localized tenderness [36]. It is important to palpate all joints and carpal bones to determine tenderness, including the snuffbox, scaphotrapeziotrapezoid (STT), scapholunate (SL), and lunotriquetral (LT) joints [181]. Tenderness in the anatomical snuffbox is suggestive of scaphoid injury [36]. Tenderness distal to Lister's tubercle is suggestive of scapholunate and lunate injury [36]. Tenderness on the dorsal margin, fingerbreadth distal to the ulnar head, is suggestive of triquetral, lunotriquetral ligament, and triquetrohamate ligament injury [36]. Swelling over the proximal carpal row is suggestive of a ligament avulsion with or without an associated fracture [36].

Physical examination findings suggestive of a scaphoid fracture include tenderness of the scaphoid in the anatomic snuffbox, pain with axial compression of the first metacarpal, and tenderness at the scaphoid tuberosity [78]. Dorsal wrist pain with loading and diminished grip strength are physical examination findings associated with dorsal intercalated segment instability (DISI) [19]. With carpal instability or dislocation, a gross deformity may be apparent, such as a marked prominence of the entire carpus dorsally which is suggestive of a perilunate dislocation [36]. Compressive stresses applied actively or passively may produce pain at the site of damage and cause a palpable and audible snap, click, shift, catch, or clunk [36]. A full examination of the contralateral wrist can often be helpful, particularly when assessing for instability [36]. For all specific physical tests for carpal instability, it is imperative to test the contralateral, uninjured wrist, which provides an internal control [181].

In rheumatoid wrist with ulnar carpal translation, symptoms include pain, weakness, and limited motion of the wrist [124]. Dorsal prominence of the ulnar head is present in rheumatoid wrist with ulnar carpal translation [124]. Tenosynovitis of the dorsal extensor compartments is usually present in rheumatoid wrist with ulnar carpal translation [124]. Metacarpophalangeal joints are frequently affected with palmar subluxation and ulnar drift in rheumatoid wrist with ulnar carpal translation [124]. Some patients with rheumatoid wrist experience extensor tendon rupture [124]. Synovitis of the carpometacarpal joints and progressive metacarpophalangeal pathology with muscular imbalance produce a pathologic palmar descent of the fourth and fifth metacarpal heads in rheumatoid wrist [124]. The clinical sign of pathologic palmar descent of the fourth and fifth metacarpal heads is always present in ulnar carpal translation [124]. Patients with dorsal malunions of the distal radius and secondary carpal dysfunction may report a clunking sensation during ulnar deviation, which may represent some degree of capitate subluxation over the extended proximal carpal row [33].

Physical Examination: Specific Tests

Scapholunate Instability: The scaphoid shift test (Watson test) is performed by applying pressure over the scaphoid tubercle while moving the wrist from ulnar to radial deviation [36]. The Watson shift test involves dorsally directed pressure over the volar scaphoid tubercle while the wrist is brought from ulnar to radial deviation, subluxating or dislocating the scaphoid over the dorsal ridge of the distal radius [19]. The scaphoid shift maneuver is positive when a palpable clunk is felt as the wrist is moved from ulnar deviation/extension to radial deviation/flexion while the examiner’s thumb applies pressure to the volar aspect of the scaphoid tubercle [181]. Pain is felt during the scaphoid shift maneuver when the scaphoid subluxes over the dorsal lip of the distal radius because the scapholunate interosseous ligament (SLIL) is incompetent [181]. Once pressure is relieved in the scaphoid shift maneuver, the scaphoid will clunk/flex back in place [181]. If the SLIL is intact, the scaphoid will flex with radial deviation and no clunk will be felt during the scaphoid shift maneuver [181]. The scaphoid shift test is positive if there is a “clunk” as the scaphoid subluxates dorsally out of the scaphoid fossa [36]. Release of pressure in the Watson shift test causes the scaphoid to reduce with a painful clunk [19]. Bilateral nonpainful clunks constitute a negative result for the Watson shift test [19]. A modified Watson maneuver is positive when pain is reproduced but no clunk is felt [181]. The scaphoid shift test is diagnostic of scapholunate disruption [36]. Up to 30% of normal wrists have a positive result on the scaphoid shift test [36].

The SL ballottement test is positive when abnormal motion or pain is appreciated between the scaphoid and the lunate by grasping the two bones separately and shucking them in opposite directions [181]. The SL ballottement test is more easily appreciated with the wrist in slight flexion [181].

Lunotriquetral Instability: The lunotriquetral shear test (Masquelet or Kleinman) involves stabilizing the lunate, grasping the triquetrum/pisiform, and generating shear force across the articulation with volar pressure on the pisiform [181]. The lunotriquetral shear test involves dorsally directed pressure to the pisiform and a palmarly directed pressure to the lunate [36]. The lunotriquetral shear test is difficult to appreciate for instability, so pain is an important clinical indicator of injury [181]. The lunotriquetral shear test is positive if it results in reproducing the patient's pain along with palpable crepitation or clicking [36]. The lunotriquetral shear test is diagnostic of lunotriquetral instability [36].

The lunotriquetral ballottement test (Linscheid or Reagan test) involves grasping the lunate between the thumb and index of one hand, and the triquetrum/pisiform between the thumb and index of the opposite hand, and shucking them in opposite directions [181]. The lunotriquetral ballottement test is positive if painful [36]. The lunotriquetral ballottement test is diagnostic of lunotriquetral instability or arthritis [36].

Midcarpal Instability: The midcarpal shift test (Lichtman) involves one hand grasping the patient’s forearm and holding it in pronation, and the contralateral hand, with the thumb pressing on the dorsum of the capitate, applying a volar force while the patient’s hand is in 15° of radial deviation [181]. The midcarpal shift test is performed by applying pressure over the dorsum of the capitate while moving the wrist from radial to ulnar deviation [36]. If instability is present during the midcarpal shift test, the carpus assumes a volar intercalated segment instability (VISI) position, with the distal row translated volarly on the proximal row [181]. Further axial loading with ulnar deviation during the midcarpal shift test allows the midcarpal joint to reduce, and the test is positive when a clunk is felt [181]. The midcarpal shift test is positive if there is a “clunk” as the lunate reduces from the palmarflexed position [36]. The midcarpal shift test is diagnostic of midcarpal instability (MCI) [36]. Stress loading the wrist with compression and motion from radial to ulnar deviation may simulate midcarpal instability and produce a “catch-up clunk” as the proximal row of carpal bones snap from flexion to extension [36].

The Lichtman test is defined as a palmar translation of the hand at the level of the distal capitate as the wrist is simultaneously loaded axially and moved from radial to ulnar deviation [35]. The Lichtman test is positive when a painful rapid 'catch-up' clunk occurs as the proximal carpal row jumps from flexion into extension, reproducing the patient's symptoms [35]. Palmar midcarpal instability was diagnosed when the Lichtman test was found to be positive during both physical examination and during wrist cineradiography in the absence of any other wrist pathology [35].

Tendon displacements with audible snaps are easily produced by some persons but are seldom symptomatic [36]. A stability test would not be accurate enough to reveal the instability of the wrist in an acute state after injury due to wrist pain and swelling [131]. Tenderness around the scaphoid, especially at the volar aspect, would be a hint of dynamic instability during follow-ups [131].

Imaging and Diagnostic Studies

The four standard views commonly employed in the assessment of scaphoid fractures can be used to detect most injuries to the carpus [36]. The four standard views include neutral posteroanterior (PA) and lateral radiographs, along with a 45-degree radial oblique (supinated anteroposterior) and a 45-degree ulnar oblique (pronated AP) views [36]. Standard neutral PA and lateral radiographs are useful for determining the presence of clear fractures and assessing carpal alignment [36]. Standard neutral PA and lateral radiographs are often poor for scaphoid fracture detection due to the tubercle overhang on the PA and the overlap on the lateral [36]. The 45-degree radial oblique, 45-degree ulnar oblique, ulnar deviated AP, Ziter's, and carpal box or tunnel views are purported to improve the ability to diagnose a fracture, particularly of the scaphoid [36]. Additional extension and flexion views are advocated for detecting intercarpal ligament injury, along with a clenched-fist and stress views [36]. Some authors advocate contralateral wrist views because of the wide range of normal alignment [36].

In the normal carpus with the wrist and hand in a neutral position, in the coronal (PA) plane a line drawn through the axis of rotation parallel with the anatomic axis of the forearm will pass through the head and base of the third metacarpal, the capitate, the radial aspect of the lunate, and the center of the lunate fossa of the radius [36]. In the sagittal (lateral) plane with the wrist and hand in a neutral position, a line will pass through the longitudinal axis of the index finger metacarpal, capitate, lunate, and the radius, with the scaphoid lying on an axis at a 45-degree angle to this line [36]. Knowledge of normal carpal alignment lines can aid in the diagnosis of carpal fracture displacement, instability, and collapse [36]. Standard radiographs should demonstrate a constant space between the scaphoid, lunate, and triquetrum throughout the range of wrist motion [36]. Assessment of joint space between the individual carpal bones is performed on the neutral PA view [36].

The VISI and DISI patterns of carpal malalignment are commonly detected using standard neutral lateral radiographs [36]. Additional views in maximal radial and ulnar deviation are used if the diagnosis of VISI or DISI is in doubt [36]. Radiographs are evaluated for fractures and gross malalignment, starting with neutral PA and lateral views [181]. SL, CL, and RL angles are visualized on a lateral radiograph [181]. The normal scapholunate (SL) angle is 30° to 60° [181]. The normal capitolunate (CL) and radiolunate (RL) angles are 0° ± 15° [181]. Assessment of Gilula lines is performed on radiographs [181]. A disrupted Gilula line indicates a fracture or ligamentous injury [181]. Contralateral radiographs are obtained to detect asymmetry [181].

Clenched-fist PA views are used to evaluate SLIL disruption [181]. Clenching pulls the capitate proximally, which forces the lunate and scaphoid apart, increasing the SL interval [181]. The normal SL interval is <4 to 5 mm [181]. Increased sensitivity for SLIL disruption is achieved with ulnar deviation, supination, and AP compared with PA views [181]. A PA view with 10° ulnar deviation is used to detect SLIL disruption [181]. The clenched pencil view involves the patient gripping a pencil or dowel with both fists, with index fingers tightly apposed and thumb metacarpals lying on the cassette [181]. Both hands are placed on the cassette for bilateral comparison in the clenched pencil view [181]. An oblique view with 20° of pronation is used to visualize the dorsum of the triquetrum [181].

Primary assessment of radiocarpal instability uses standard scaphoid radiographs to detect displacement and associated fractures [51]. Provocative stress tests may be required to demonstrate dynamic radiocarpal instability [51]. In patients with ulnar translation, the radiographic appearance is often dramatic with the lunate positioned just distal to the ulna and a large space between the radial styloid and the scaphoid [51]. If a perilunate injury is also present in ulnar translation, the lunate and triquetrum slide ulnarly, opening a gap between the scaphoid and lunate [51]. In some cases of ulnar translation, the shift is subtle, and a decrease in the ulnocarpal index may provide the only clue to diagnosis [51]. Chronic causes for ulnar translation include rheumatoid arthritis and developmental deformities such as Madelung deformity [51].

Computed radiography (Fuji) is most useful to evaluate the relationship of the carpal bones in cases of dislocation or carpal instability [13]. Static imaging techniques may accurately depict major wrist ligamentous injury [55]. Dynamic ultrasound and videofluoroscopy may demonstrate dynamic instability and kinematic dysfunction [55]. Bone scintigraphy was not useful for the detection or exclusion of carpal instability [17]. Dynamic fluoroscopic imaging enables dynamic testing of carpal stability and asynchronous carpal motion [181].

CT may be required to better define associated bony injuries in radiocarpal instability [51]. CT is not commonly obtained when carpal instability is of concern, unless instability is secondary to a carpal fracture [181]. CT arthrography has high sensitivity and specificity but has been mostly replaced by MRI or a fracture malunion [181]. MRI can be used to determine the extent of ligamentous disruption in radiocarpal instability [51]. High-resolution MRI is an advanced imaging modality of choice for carpal instability [181]. The sensitivity and specificity of ligament disruption on MRI increases with intra-articular contrast injection and use of a 3-Tesla coil [181]. Indications for MRI include pain localized over a particular ligament, positive provocative physical examination testing with negative radiograph, and unclear diagnosis with continued symptoms refractory to nonsurgical treatment [181]. Arthroscopy is the benchmark for diagnosing ligament

Investigations

Clinical Examination

Physical examination remains the primary tool for localizing carpal pathology. Tenderness in the anatomical snuffbox indicates scaphoid injury [36], while tenderness distal to Lister's tubercle suggests scapholunate and lunate injury [36]. Pain on the dorsal margin, one fingerbreadth distal to the ulnar head, indicates triquetral, lunotriquetral ligament, and triquetrohamate ligament injury [36]. A full examination of the contralateral wrist is helpful when assessing for instability [36].

Specific provocative tests aid in the diagnosis of instability. The scaphoid shift test involves pressure applied over the scaphoid tubercle while the wrist moves from radial to ulnar deviation [36]; however, a positive scaphoid shift was not correlated with radiographic carpal malalignment [206]. The midcarpal shift test involves pressure applied over the dorsum of the capitate during radial to ulnar deviation and is diagnostic of midcarpal instability [36]. Lunotriquetral ballottement is performed by fixing the lunate with the thumb and index finger of one hand while displacing the triquetrum palmarly and dorsally with the thumb of the other hand [36]. This test is positive if painful and is diagnostic of lunotriquetral instability or arthritis [36].

Plain Radiography

Standard neutral posteroanterior and lateral radiographs are useful for determining the presence of clear fractures and assessing carpal alignment [36]. However, these views are often poor for scaphoid fracture detection due to the tubercle overhang on the PA view and overlap on the lateral view [36]. Plain radiography is approximately 50% sensitive for the detection of a scaphoid fracture and less than 50% for the other carpal bones [127]. If a scaphoid fracture is suggested but radiographs are negative, the wrist should be immobilized and reevaluated in 2 weeks because up to 30% of patients may have positive follow-up radiographs [127].

Carpal alignment is assessed using specific geometric lines. In the normal carpus with the wrist and hand in a neutral position, a line drawn through the axis of rotation parallel with the anatomic axis of the forearm will pass through the head and base of the third metacarpal, the capitate, the radial aspect of the lunate, and the center of the lunate fossa of the radius [36]. In the sagittal plane with the wrist and hand in a neutral position, a line will pass through the longitudinal axis of the index finger metacarpal, capitate, lunate, and the radius, with the scaphoid lying on an axis at a 45-degree angle to this line [36]. An alternate method of diagnosing carpal instability has been presented for evaluating carpal alignment on lateral radiographs [39]. Measurements of carpal bone angles on lateral wrist radiographs can be of assistance in the diagnostic evaluation of wrist malalignment [203]. Roentgenograms of both wrists are valuable in the evaluation of patients with chronic bilateral scapholunate dissociation [211].

MRI

Magnetic resonance imaging has the highest sensitivity in detecting an occult scaphoid fracture [52]. MRI is more sensitive than CT and is useful in making the diagnosis of scaphoid fractures [127]. A normal MRI study as early as 2 days after injury has a negative predictive value of 100% for scaphoid fracture [127]. MRI may be more helpful to exclude potential alternative diagnoses in the patient with ulnar wrist pain [208]. However, the inconsequent use of available modern magnetic resonance imaging (MRI) techniques and the lack of reliable preoperative diagnoses necessitated pure diagnostic arthroscopies for ulnar-sided wrist pain [210]. It is not clear whether diagnosis of subtle injuries only demonstrated on MRI improves outcomes in patients with posttraumatic radial wrist tenderness [213]. Dorsal wrist capsular impingement is a clinical diagnosis; magnetic resonance imaging may be helpful in evaluating for other pathologies [178]. Type 2 Preiser’s disease cases have MRI signal changes involving only part of the scaphoid [209].

CT

CT or MR imaging is recommended as the presence or absence of carpal collapse is important for surgical decision-making in Kienböck’s disease [155]. CT scan and MRI scan are indispensable in the investigation of carpal lesions such as exostoses, allowing better visualization of the base of the tumour, expansion, relation to neighbouring soft tissues, and presence of malignant degeneration [193].

Bone Scan

Bone technetium scintigraphy and X-ray computerised tomographic scanning of the wrist show value in patients with persistent and atypical pain in the carpus [215].

Cineradiography

Cineradiography is a qualitative rather than a quantitative tool, and more research is needed to determine its exact role in diagnosing carpal instability [197].

Other Considerations

Approximately 25% of perilunate dislocations are missed during initial emergency department evaluations [52]. Carpal instability is a missed diagnosis in patients with clinically suspected scaphoid fracture [17]. A thorough clinical evaluation guides the differential diagnosis and bolsters the need for further imaging in the setting of negative radiographs [34]. Delays in diagnosis should be avoided to prevent complications such as nonunion and secondary displacement [34]. Accurate diagnosis and management of hand and carpal fractures and dislocations are predicated on a thorough physical examination and appropriate imaging to limit joint stiffness while preserving mobility and function [58]. There is a lack of a generally agreed analysis of carpal instability that can assist in the diagnosis, give guidelines for treatment, and ensure unity when reporting results of treatment [3]. Degenerative disorders of the wrist are complex in their clinical and radiographic manifestations, with classification and understanding of pathomechanics important for treatment selection [9]. Early diagnosis and management are necessary to prevent major sequelae such as instability and carpal bone necrosis in perilunate luxation [1]. Volar perilunar dislocations of the carpus are exceptional lesions with a generally good prognosis provided there is early diagnosis and anatomical reduction of intracarpal relationships [65]. Fracture displacement leading to a predictable collapse pattern of carpal instability must be recognized so that appropriate management can be provided [34].

Before surgery for scaphoid nonunion, a thorough assessment is required to establish the extent of bony collapse, osteonecrosis, and carpal malalignment [10]. A comparison of the carpal height to that of the contralateral wrist allows the extent of collapse and scaphoid shortening to be estimated [10]. A diagnosis of osteonecrosis can be challenging because of the limited sensitivity of imaging modalities, including contrast-enhanced MRI [10]. The presence of large cavitary lesions or cysts with bone resorption around the midwaist to proximal pole suggests that the bone has a compromised blood supply [10]. Subjective, clinical and radiological evaluations gave different results for silastic implants of the scaphoid and lunate, with radiological findings showing lytic lesions in all except two cases and a trend towards fusion between carpal bones [22].

Treatment

Non-Operative

Nonsurgical management of carpal instability includes NSAIDs, splinting, casting, and steroid injections [194]. For suspected predynamic scapholunate or lunotriquetral instability, initial treatment with a cast is appropriate [194]. Patients with chronic carpal instability can often be managed with splintage, analgesics, and specific physiotherapy [172]. In palmar carpal instability nondissociative, initial management is nonsurgical, with most patients responding to this approach alone [141]. Nonsteroidal anti-inflammatory drugs and activity modification typically relieve symptoms in this condition [141]. A splint with ulnar volar support helps reduce symptomatic volar sag of the proximal row and maintains the lunate in a neutral position [141]. Hand therapy should focus on reestablishing proprioceptive control of the wrist [141]. Isometric strengthening of the flexor carpi ulnaris and extensor carpi ulnaris muscles counteracts flexion of the proximal carpal row by generating a realigning force to the pisotriquetral unit [141]. Nonoperative approaches are recommended for appropriate candidates with predynamic or dynamic midcarpal instability [212]. A wrist exercise program for palmar midcarpal instability was evaluated in a study of patients diagnosed between 2005 and 2011 [35]. Successful outcomes have been reported with nonsurgical management and delayed nonfusion surgery for traumatic volar carpal instability nondissociative [156]. However, nonsurgical management of perilunate fracture-dislocations results in progressive arthritis and poor long-term outcomes [87].

Operative

Indications: Early diagnosis and management of perilunate dislocations are necessary to prevent major sequelae such as instability and carpal bone necrosis [1]. Perilunate dislocations almost always require surgical treatment [194]. Surgical fixation is recommended for all acute perilunate injuries, even after anatomic closed reduction, because of the extent of instability [168]. Prompt recognition and surgical treatment with anatomic reduction of carpal malalignment improve the likelihood of optimal, long-term clinical success and patient satisfaction for perilunate dislocations [134]. Aggressive surgery for carpal dislocation presenting after delay up to six months is not justified [46].

Surgical Approach / Technique: Stabilization of the carpal bones and maintenance of reasonable mobility are primary goals that can usually be obtained by techniques other than arthrodesis [6]. Perilunate dislocations require urgent reduction and immobilization to relieve pressure on the median nerve and soft tissues [194]. Closed reduction can be performed with a relaxed or sedated patient using the Tavernier method, which involves traction, extending the wrist, and gradually flexing the wrist with volar pressure on the lunate with the thumb [194]. Postreduction X-rays are essential to evaluate reduction, and a CT scan should be obtained to look for concomitant fractures [194]. Closed reduction and percutaneous pinning requires an anatomic reduction of the carpus, which can be difficult with a closed technique [194]. Fixation pins are commonly placed across the lunotriquetral, scapholunate, and scaphocapitate intervals [194]. Headless compression screws may be used for fixation of concomitant scaphoid fractures [194]. Closed reduction and percutaneous pinning is often combined with open carpal tunnel release, as needed [194]. A carpal tunnel release may be added in the setting of median nerve symptoms for acute perilunate injuries [168]. Chronic perilunate injuries may be managed either in the same manner as acute injuries or with a proximal row carpectomy [168]. Arthroscopic reduction and percutaneous fixation of perilunate dislocations and fracture-dislocations has satisfactory outcomes [168]. Interposed palmar capsular ligaments were found in all patients surgically treated after unsuccessful closed reduction of perilunate dislocations [168].

For scapholunate instability, partial ligament injuries resulting in predynamic or dynamic instability are treated with nonoperative treatment or arthroscopic débridement [19]. Acute scapholunate ligament rupture is rarely amenable to primary repair alone [19]. After delayed diagnosis, treatment involves open reduction of the scapholunate interval and K-wire pinning with or without dorsal capsulodesis or tendon autograft reconstruction [19]. Closed reduction and percutaneous pinning can be used if part of the ligament remains intact after débridement [194]. Temporary pins inserted dorsally into the scaphoid and lunate act as joysticks to correct scaphoid flexion and lunate extension during pinning [194]. Commonly, two 0.045-inch Kirschner wires are placed across the scapholunate interval, and one is placed across the scaphocapitate interval for further stabilization [194]. Arthroscopic ligament débridement with or without thermal shrinkage is used for low-grade tears (Geissler I/II) with no frank instability [194]. Open reduction and ligament repair and pinning is performed if the ligament is repairable and the scaphoid is reducible [194]. Open reduction with ligament reconstruction using a tendon graft is performed if the scaphoid is reducible and the ligament is not repairable [194].

For lunotriquetral instability, options for ligament disruption or volar intercalated segment instability deformity include arthroscopic débridement [194]. Closed reduction and percutaneous pinning using dorsal joysticks to correct the deformity is an option [194]. Open reduction and ligament repair with bone anchor or transosseous sutures is an option [194]. Open reduction and ligament reconstruction using a distally based strip of the extensor carpi ulnaris passed through the lunate and triquetrum and sutured to itself may be superior to arthrodesis or primary repair of the lunotriquetral interosseous ligament [194]. Lunotriquetral arthrodesis with bone graft and screws or staples is an option [194].

Implant Selection: Various tendon grafts (e.g., Brunelli, SL360, ANAFAB) and bone-retinaculum-bone grafts have been attempted for scapholunate reconstruction [19]. In the Brunelli tenodesis, the flexor carpi radialis is harvested, and insertion left intact, then pulled through a tunnel in the scaphoid and attached to the dorsal ulnar corner of the radius [194]. In the tri-ligament tenodesis, the flexor carpi radialis is fixed dorsally to the lunate, passed through a slit in the dorsal radiocarpal ligament, and sutured back on itself to recreate the scapholunate and dorsal radiocarpal ligaments [194]. The scapholunate ligament internal brace 360° tenodesis (SLITT) uses a tendon graft and internal brace to reconstruct the volar and dorsal scapholunate interosseous ligament and secondary stabilizers without Kirschner wires [194]. Dorsal capsulodesis can be performed in isolation if the ligament is not repairable and the scaphoid is reducible, or used to augment ligament repair or reconstruction [194]. In the Blatt capsulodesis, a flap of the dorsal wrist capsule is attached to the dorsal pole of the scaphoid and left proximally attached to the distal radius [194]. In the Mayo capsulodesis, a proximal strip of the dorsal intercarpal ligament is detached from the triquetrum, rotated proximally, and attached to the dorsal lunate [194]. The reduction and association of the scaphoid and lunate (RASL) screw creates a pseudarthrosis using a partially threaded headless compression screw [194]. Limited clinical data exist on the reduction-association of scaphoid and lunate (RASL) procedure or other forms of implants to span the scapholunate joint [19].

Alignment / Balancing Strategy: Intercarpal fusions may be used in Stage IV scapholunate dissociation with static irreducible deformities without arthritis [194]. Scapholunate advanced collapse (SLAC) treatment depends on the condition of articular surfaces and competency of the radioscaphocapitate ligament [19]. Radial styloidectomy with or without partial wrist denervation is indicated for stage 1 SLAC [19]. Proximal row carpectomy is indicated for stage 2 SLAC when the proximal capitate is spared of arthrosis and requires a competent radioscapholunate ligament [19]. Scaphoid excision and four-corner or isolated capitolunate fusion is indicated for stage 2 or 3 SLAC if the proximal lunate is spared of arthrosis and is contraindicated in smokers [19]. Total wrist fusion is indicated for stage 3 SLAC with diffuse radiocarpal and midcarpal changes [19]. Partial wrist denervation is often done in conjunction with SLAC procedures but is also an option on its own [19].

Other Considerations: The fact that arthritic changes were observed in only 1 of 8 cases suggests that carpal stability obtained by modified Brunelli tenodesis is probably sufficient to obtain good functional long-term results [4]. Although ongoing scapholunate instability resulted in early arthritic degeneration after dorsal intercarpal ligament capsulodesis, most patients had acceptable long-term function of the wrist [5]. No patient required secondary surgery or treatment related to the carpal stabilization after anatomical anterior and posterior reconstruction for scapholunate dissociation [21]. Despite the evolution of diagnostic and treatment options, the ideal treatment for scapholunate instability remains an unresolved problem with inconsistent results and ongoing concerns regarding complications [27]. Treatment of subacute and chronic flexible carpal instabilities associated with scapholunate dissociation with the dorsal intercarpal augmentation offers some potential advantages [44]. A satisfactory outcome was achieved in all twelve patients whose treatment for scaphoid nonunion included intercarpal ligamentous reconstruction [77]. The authors do not recommend proximal row carpectomy for the management of scapholunate dissociation in the absence of degenerative changes due to disappointing results compared to other treatments [67]. Grade I injury of the scapholunate or lunotriquetral ligament with no joint incongruence typically resolves with immobilization alone [175]. Acute tears of the scapholunate or lunotriquetral ligament (less than 4 to 6 weeks) that result in incongruence from the midcarpal space may be arthroscopically reduced and temporarily pinned [175]. This arthroscopic reduction and pinning procedure is suitable for Geissler grade II and III scapholunate and lunotriquetral ligament acute tears and in chronic partial scapholunate ligament tears [175]. In a retrospective study of 18 consecutive patients undergoing arthroscopic reduction association of the scapholunate joint, the mean Disabilities of the Arm, Shoulder and Hand score was 22 and hardware removal was required in one-third of cases for loosening [143]. The modified Viegas dorsal capsuloplasty was used to treat partial chronic scapholunate ligament lesions in young athletes with a minimum follow-up of 24 months [145]. Patients with osteoarthritic changes on preoperative imaging were excluded from the modified Viegas dorsal capsuloplasty study as they were not considered eligible for this surgery [145]. The radiographic correction achieved by the modified Brunelli technique versus the Blatt capsulodesis might correlate with improved carpal dynamics and improved clinical outcomes [154]. For the treatment of occult ganglions of the dorsal scapho-lunate ligament, removal of the distal fibres of the dorsal scapho-lunate ligament is recommended to lower the incidence of recurrence without producing carpal instability [157]. The inherent instability of scapho-lunate dissociation occurring with scaphoid fracture has a high scaphoid non-union rate, and treatment by open reduction and internal fixation is recommended if identified [217].

Neglected scaphoid nonunion is associated with osteonecrosis and progressive radiocarpal and midcarpal arthritis, a condition called scaphoid nonunion advanced collapse [10]. A stable scaphoid nonunion without deformity or osteonecrosis can be successfully managed without bone grafting [10]. Twelve of 14 patients with fibrous scaphoid nonunions treated with screw fixation alone experienced healing at 4.4-month follow-up [10]. The two persistent nonunions in the screw fixation alone series occurred in proximal pole fractures more than 1 year after injury [10]. Twelve scaphoid waist nonunions with humpback deformity were successfully managed with a retrograde screw and ipsilateral distal radius cancellous bone graft [10]. A systematic review found that both cancellous and corticocancellous bone grafting led to reliable union (95% or 92%, respectively) for scaphoid nonunions [10]. Cancellous grafting required less time to union, but corticocancellous grafting led to more consistent deformity correction in scaphoid nonunions [10]. Vascularized bone grafting has been recommended for the management of scaphoid nonunion complicated by carpal collapse, proximal pole osteonecrosis, and/or the revision fixation scenario [10]. The 1,2 intercompartmental supraretinacular artery was commonly used as a vascularized pedicled bone graft for scaphoid nonunion, although it has begun to fall out of favor compared with other vascularized grafts [10]. The Mathoulin pedicled graft from the volar distal radius has been used with good clinical results for scaphoid nonunion and has the advantage of a corticocancellous component to help maintain the stability of the realigned scaphoid [10]. The free medial femoral condyle vascularized graft can be used as a primary corticocancellous bone graft for scaphoid nonunion with a reported union rate of 94% [10]. The free medial femoral condyle vascularized graft has demonstrated superior performance in revision scenarios for scaphoid nonunion, with a union rate of 84% [10]. For proximal one-fifth scaphoid nonunions, a novel replacement technique uses a free vascularized medial femoral trochlea osteocartilaginous flap [10]. At a minimum 6-month follow-up, CT-confirmed healing was found in 15 of 16 scaphoids consecutively treated with a medial femoral trochlea flap [10]. In the medial femoral trochlea flap cases, the scapholunate ligament was preserved to prevent instability [10]. This technique requires the advanced skills of a microvascular flap surgeon and donor morbidity of the knee must be considered [10]. Proximal hamate autograft is an alternative, nonvascularized option for proximal pole scaphoid reconstruction, although clinical outcomes are limited [10]. Acutrak screw fixation led to a significantly higher union rate than Herbert screw fixation (94% versus 71%, P = 0.01) and to more accurate central axis screw placement in a review of 132 scaphoid nonunions [10]. Distal scaphoid resection is a durable procedure [10].

Complications

Natural History and Degenerative Progression

Untreated scaphoid nonunion carries a high risk of degenerative joint disease. In a review of 55 patients, arthritis developed in 31 of 32 patients (97%) who had been injured five years or more earlier [199]. The incidence of osteoarthritis in scaphoid nonunion increases with time after injury [199]. Consequently, patients with established scaphoid non-union should be advised that osteoarthritis will most likely develop [199].

Persistent carpal instability leads to degenerative changes as a consequence of increased shear forces and abnormal contact between individual carpal bones [43]. In scapholunate dissociation, increased compressive and shear stress on the dorsal and lateral aspect of the radioscaphoid articulation ultimately leads to cartilage loss and osteoarthritis [32]. The radiolunate articular cartilage is spared until very late in the degenerative process of scapholunate dissociation because the lunate and lunate facet of the radius remain perfectly congruent [32].

In a series of arthroscopically proven scapholunate ruptures without initial SL widening or DISI, all patients developed SLAC changes and wrist pain at an average of seven years, but none developed SLAC functional sequelae [32]. Although ongoing scapholunate instability resulted in early arthritic degeneration, most patients had acceptable long-term function of the wrist [5]. Arthritic changes were observed in only 1 of 8 cases treated with modified Brunelli tenodesis for static scapholunate instability [4]. A study found a higher than anticipated cumulative incidence of carpal instability in the second year post-injury [85].

Specific Complications and Pathologies

SNAC: Scaphoid nonunion advanced collapse (SNAC) is characterized by osteonecrosis and progressive radiocarpal and midcarpal arthritis [10]. SLAC: Scapholunate advanced collapse (SLAC) is defined as chronic untreated static scapholunate instability [19]. In SLAC, the radiolunate joint is often spared [19]. DISI: Dorsal intercalated segmental instability (DISI) can be caused by Kienböck disease, long radiolunate injury, dorsal intercarpal ligament injury, perilunate injury/dislocation, distal radius fracture, or distal radius fracture nonunion [16]. Scaphoid malunion may cause poor clinical outcomes due to a dorsal intercalated segmental instability (DISI) deformity [205]. VISI: Volar intercalated segmental instability (VISI) can be caused by disruption of the lunotriquetral interosseous ligament (traumatic or from ulnar impaction), dorsal radiocarpal ligament injury, volar radiolunate ligament injury, rheumatoid arthritis, and possibly crystalline arthropathies [16]. Translocation: Ulnar translocation is seen commonly in rheumatoid arthritis, Madelung deformity, and after injury to the radioscaphocapitate ligament after trauma or surgery (radial styloidectomy, four corner arthrodesis, proximal row carpectomy, scaphocapitate fusion) [16]. Dorsal translocation commonly results from a malunited distal radius fracture with residual dorsal angulation as the carpus begins to migrate dorsally [16].

Other Pathologies: An osteochondroma of the carpal scaphoid may remain unrecognized until the second or third decade of life, when incidental trauma brings it to attention [195]. A dislocation is only unstable in the early stages of the injury; with time, the unreduced dislocation becomes stiff, and stiffness is the opposite of instability [82]. Chronic unreduced fracture-dislocations tend to progress to stiffness and degenerative disease rather than remaining a carpal instability problem [82].

Iatrogenic and Procedural Complications

Arthrodesis Complications: The second most common complication of scaphocapitate arthrodesis is persistent wrist pain despite radiographic evidence of bony union, occurring in 4/30 patients (13%) [25]. Although radiographic carpal collapse and ulnar translocation occurred after scaphocapitate arthrodesis for Kienböck disease, patients were not symptomatic [37]. Prosthetic and Implant Failures: In a series of 17 wrist prostheses, a five-year follow-up found a too frequent lack of retention of the carpal plate [83]. Silastic implants of the scaphoid and lunate showed radiological findings of lytic lesions in all except two cases and a trend towards fusion between carpal bones [22]. Surgical Technique Risks: A wedge excision for carpal boss disturbs normal anatomy and creates instability of the involved carpometacarpal joint by approximately doubling the passive range of motion [188]. Collapse after carpal bone tunneling is an underreported complication with unknown incidence, but its consequences could be substantial [166]. Patients should be warned of the possibility of carpal bone tunnel collapse when discussing complications of ligament reconstruction for chronic scapholunate instability requiring the creation of a bone tunnel [166]. Flap and Graft Considerations: Donor morbidity of the knee must be considered when using a free vascularized medial femoral trochlea osteocartilaginous flap for proximal one-fifth scaphoid nonunions [10]. The technique of using a free vascularized medial femoral trochlea osteocartilaginous flap requires the advanced skills of a microvascular flap surgeon [10].

Other Considerations

Long-term clinical prospective trials are needed to examine whether scapholunate dysfunction and osteoarthritic changes are prevented by modified arthroscopic volar scapholunate capsuloligamentous repair [180]. Longer follow-up is needed to evaluate the ultimate outcome of the new radio-capitate joint after proximal row carpectomy through a volar approach [80]. The absence of carpal collapse and good functional results after lunate replacement with a costal cartilage graft are encouraging, but the follow-up is short [12]. There has been no long-term deterioration of wrist function following the use of costo-osteochondral grafts in the wrist [72]. Clinical and radiological long-term results showed a stable distal radioulnar joint in Galeazzi lesions [70].

Recovery

Other Considerations: The provided evidence base for this section consists exclusively of long-term outcome data, complication rates, and prognostic factors derived from follow-up studies. It does not contain specific timelines for light activity, full activity, complete recovery, or defined rehabilitation protocols (e.g., immobilization duration or weight-bearing progression). Consequently, the standard recovery phase labels (Light activity, Full activity, Complete recovery / outcome plateau) and Rehabilitation protocol are omitted as no genuine recovery-timeline evidence exists in the source material. The following details address long-term functional outcomes and complications relevant to post-operative management.

General Prognosis and Complications: Prognosis in traumatic axial dislocations of the carpus is determined more by associated soft tissue injuries than by the carpal derangement itself, with an average follow-up of 61 months [74]. A study found a higher than anticipated cumulative incidence of carpal instability in the second year post injury following a fall onto an outstretched hand [85].

Scapholunate Instability Outcomes: Carpal stability obtained by modified Brunelli tenodesis is probably sufficient to obtain good functional long-term results, as arthritic changes were observed in only 1 of 8 cases [4]. Although ongoing scapholunate instability resulted in early arthritic degeneration after dorsal intercarpal ligament capsulodesis for chronic scapholunate instability, most patients had acceptable long-term function of the wrist [5]. For patients followed up for an average of 66 months after repair of the scapholunate interosseous ligament and dorsal capsulodesis for dynamic scapholunate instability, results clinically and radiographically appear to deteriorate in those who place high demands on the wrists on a daily basis [219]. At 17.9-month average follow-up, radiographic and patient-reported outcome parameters improved after reconstruction of the critical dorsal and volar ligament stabilizers of the proximal carpal row with the ANAFAB technique for scapholunate dissociation [184]. At 1 year after surgery for scapholunate ligament disruption in a skeletally immature patient, preservation of a normal carpal alignment was noted and there was restoration of a full range of motion of the wrist [191].

Midcarpal Instability Outcomes: Long-term functional results were evaluated for patients with palmar midcarpal instability treated with a wrist exercise program [35].

Arthrodesis and Resection Outcomes: Intercarpal arthrodesis can successfully treat chronic carpal instability resulting from trauma, as suggested by a retrospective review of five patients [23]. Wrist arthrodesis using dorsal radial bone graft showed union in all 16 patients at a follow-up over an average period of 18.1 months [221]. The second most common complication of scaphocapitate arthrodesis is persistent wrist pain despite radiographic evidence of scaphocapitate bony union, occurring in 4/30 patients (13%) [25]. Longer follow-up is needed to evaluate the ultimate outcome of the new radio-capitate joint following proximal row carpectomy through a volar approach [80].

Kienböck Disease and Bone Grafting Outcomes: Radiographic disease progression occurred only in 2 wrists, rated stage IIIB, at 8 and 10 years follow-up without a bad clinical outcome after capitate shortening osteotomy for stage IIIA Kienböck disease [187]. The absence of carpal collapse and good functional results are encouraging for lunate replacement by costal cartilage graft in advanced Kienböck disease, but the follow-up is short [12].

Other Procedures and Implants: Subjective, clinical, and radiological evaluations of Silastic implants of the scaphoid and lunate gave different results, with radiological findings showing lytic lesions in all except two cases and a trend towards fusion between carpal bones [22]. With a five-year follow-up, a series of 17 wrist prostheses found a too frequent lack of retention of the carpal plate [83].

Key Evidence

• [L4] Early diagnosis and management are necessary to prevent major sequelae such as instability and carpal bone necrosis. [1] (10.1016/j.hansur.2017.10.201)
• [L5] There is a lack of a generally agreed analysis of carpal instability that can assist in the diagnosis, give guidelines for treatment, and ensure unity when reporting results of treatment. [3] (10.1016/s0363-5023(05)80426-5)
• [L4] The fact that we observed arthritic changes in only 1 of 8 cases suggests that carpal stability obtained by this procedure is probably sufficient to obtain good functional long-term results. [4] (10.1016/j.jhsa.2013.02.022)
• [L3] Although the consequent ongoing scapholunate instability resulted in early arthritic degeneration, most patients had acceptable long-term function of the wrist. [5] (10.1302/0301-620x.94b12.30007)
• [L5] Stabilization of the carpal bones and maintenance of reasonable mobility are primary goals that can usually be obtained by techniques other than arthrodesis. [6] (10.1016/s0363-5023(82)80138-x)
• [L5] [7] (10.1016/j.hcl.2015.04.011)
• [Paper] Degenerative disorders of the wrist are complex in their clinical and radiographic manifestations, with classification and understanding of pathomechanics important for treatment selection. [9] (10.1016/s0363-5023(85)80025-3)
• [L4] All wrists showed improvement or resolution of instability. [11] (10.1016/j.jhse.2007.03.012)
• [L4] The absence of carpal collapse and good functional results are encouraging but the follow up is short. [12] (10.1016/j.main.2011.04.005)
• [L4] Therefore this method is most useful to evaluate the relationship of the carpal bones in cases of dislocation or carpal instability. [13] (10.1016/0363-5023(89)90125-1)
• [L2] Bone scintigraphy was not useful for the detection or exclusion of carpal instability. [17] (10.1016/0020-1383(93)90182-6)
• [L5] Midcarpal instability is a collective term for conditions where wrist instability is predominantly between the proximal and distal carpal rows, with palmar midcarpal instability being the most common type. [18] (10.1177/1753193415617756)
• [L4] No patient required secondary surgery or treatment related to the carpal stabilization. [21] (10.1177/1753193419886536)
• [L4] Subjective, clinical and radiological evaluations gave different results, with radiological findings showing lytic lesions in all except two cases and a trend towards fusion between carpal bones. [22] (10.1016/0266-7681(93)90223-3)
• [L4] A retrospective review of five patients with chronic carpal instability resulting from trauma suggests that this condition can be successfully treated by intercarpal arthrodesis. [23] (10.1016/s0363-5023(84)80060-x)
• [Paper] The second most common complication is persistent wrist pain despite radiographic evidence of scaphocapitate bony union, occurring in 4/30 patients (13%). [25] (10.1097/00130911-200206000-00003)
• [L4] Distal scaphoid resection is a durable procedure with good long-term results. 94% of patients remained satisfied, and no further wrist collapse or radiocarpal arthritis developed. [26] (10.1016/s0363-5023(11)60002-6)
• [L5] Despite the evolution of diagnostic and treatment options, the ideal treatment for scapholunate instability remains an unresolved problem with inconsistent results and ongoing concerns regarding complications. [27] (10.1177/17531934221148009)
• [L4] [31] (10.1016/s0363-5023(05)80427-7)
• [L4] [35] (10.1055/s-0037-1612594)
• [L4] Although radiographic carpal collapse and ulnar translocation occurred, patients were not symptomatic. [37] (10.1016/j.jhsa.2014.12.013)
• [L4] Correct diagnosis and proper surgical indications are necessary to reduce the number and enhance the efficacy of operations required to treat carpal boss. [38] (10.1016/j.jhsa.2007.11.029)
• [Paper] An alternate method of diagnosing carpal instability has been presented. [39] (10.1016/s0363-5023(85)80087-3)
• [L5] The aim of this themed issue is to provide answers regarding the investigation and management of the unstable wrist, highlighting the need for collaborative working and the referral of cases to specialized centers to run randomized controlled trials due to the lack of objective evidence on long-term outcomes. [40] (10.1177/1753193415617100)
• [L4] Patients with palmar midcarpal instability may have significant disability that may be refractory to nonsurgical management. [41] (10.1016/0363-5023(93)90366-b)
• [L5] Early accurate diagnosis of intrinsic carpal ligament injuries provides for best outcomes, while delayed diagnosis leads to arthritis within 10 years if not treated. [42] (10.1016/j.hcl.2015.01.003)
• [L4] Treatment of subacute and chronic flexible carpal instabilities associated with scapholunate dissociation with the dorsal intercarpal augmentation offers some potential advantages. [44] (10.1097/00130911-200312000-00005)
• [L4] Aggressive surgery for carpal dislocation presenting after delay up to six months is not justified. [46] (10.1016/0266-7681(92)90073-b)
• [L4] Static imaging techniques may accurately depict major wrist ligamentous injury, while dynamic ultrasound and videofluoroscopy may demonstrate dynamic instability and kinematic dysfunction. [55] (10.1177/1753193415610515)
• [Paper] The complex nature of the wrist has plagued us clinically and hampered our ability to formulate concise, yet thorough, algorithmic approaches to evaluation and treatment. [56] (10.1016/s0894-1130(96)80065-2)
• [L5] The article summarizes current thinking regarding the diagnosis and treatment of clinically important carpal instabilities, emphasizing that the row theory more clearly accounts for the function of the wrist than the column theory. [63] (10.2106/00004623-199503000-00019)
• [L4] Volar perilunar dislocations of the carpus are exceptional lesions with a generally good prognosis provided there is early diagnosis and anatomical reduction of intracarpal relationships. [65] (10.1016/s1297-3203(00)73486-x)
• [L4] The authors do not recommend PRC for the management of scapholunate dissociation in the absence of degenerative changes due to disappointing results compared to other treatments. [67] (10.1177/1753193410382719)
• [L5] Contraindications include degenerative arthritic changes, unreducible dissociation, inadequate SLIL tissue, and other carpal ligamentous disruptions or fractures. [68] (10.1097/00130911-199812000-00007)
• [L4] Clinical and radiological long-term results showed a stable distal radioulnar joint. [70] (10.1177/1558944716660555if)
• [L4] There has been no long term deterioration of wrist function. [72] (10.1097/00130911-200109000-00008)
• [L4] [73] (10.1177/1753193415595167)
• [L4] An average follow-up of 61 months showed that prognosis was determined more by the associated soft tissue injuries than by the carpal derangement itself. [74] (10.1016/s0363-5023(89)80003-6)
• [L5] They were easy to perform, safe, and seemed useful in indications for ligament or bony intracarpal repairs. [75] (10.1177/1558944716660555hr)
• [L4] A satisfactory outcome was achieved in all twelve patients whose treatment included intercarpal ligamentous reconstruction. [77] (10.1016/0266-7681(86)90260-3)
• [L5] The author argues that carpal-sparing surgery like radial shortening osteotomy gives very good and lasting clinical results in KD with carpal collapse. [79] (10.1177/17531934231205707)
• [L4] Longer follow-up is needed to evaluate the ultimate outcome of the new radio-capitate joint. [80] (10.1016/s0363-5023(03)80411-2)
• [L5] The article outlines the historical development and pathomechanics of midcarpal instability, noting a lack of unanimity regarding etiology, terminology, and treatment. [81] (10.1016/j.jhsa.2005.12.014)
• [L4] With a five-year follow-up, the series found a too frequent lack of retention of the carpal plate. [83] (10.1016/j.main.2012.10.043)
• [L4] This study found a higher than anticipated cumulative incidence of carpal instability in the second year post injury. [85] (10.1016/j.jht.2017.11.014)
• [L4] Excisional arthroplasty is highly recommended for idiopathic, symptomatic, isolated STT osteoarthritis without midcarpal instability, as it provides reliable results, is less technically demanding, requires less prolonged immobilization, and has fewer complications than localized arthrodesis. [86] (10.1016/j.jhsa.2010.12.016)
• [L5] A wrist joint should be considered biomechanically unstable when it is not able to bear loads and does not exhibit normal kinematics throughout its arc of motion. [89] (10.1053/jhsu.1999.0866)
• [L4] In normal wrists, motion occurred equally at the midcarpal and radiocarpal joints. [113] (10.1016/s0266-7681(97)80050-2)
• [L4] [124] (10.1097/00130911-200006000-00006)
• [L4] [131] (10.1186/s12891-021-04857-7)
• [L4] Prompt recognition and surgical treatment with anatomic reduction of carpal malalignment improve the likelihood of optimal, long-term clinical success and patient satisfaction. [134] (10.1016/j.jhsa.2012.07.034)
• [L5] [141] (10.5435/00124635-201209000-00004)
• [L4] [143] (10.1177/1753193415577335)
• [L4] [145] (10.1177/1753193420939490)
• [L4] We find it important to differentiate between SNAC and SLAC-Wrist for classification and preoperative planning in treatment of advanced carpal collapse. [147] (10.1016/0266-7681(94)90353-0)
• [L5] This correction might correlate with improved carpal dynamics and improved clinical outcomes. [154] (10.1016/j.jhsa.2010.06.029)
• [L3] CT or MR imaging is recommended as the presence or absence of carpal collapse is important for surgical decision-making. [155] (10.1177/17531934231153966)
• [L4] Contrary to existing literature, the authors report successful outcomes with nonsurgical management and delayed nonfusion surgery for traumatic volar carpal instability nondissociative (CINDT-VISI). [156] (10.1016/j.jhsg.2023.07.001)
• [L4] For the treatment of the lesion, removal of the distal fibres of the dorsal scapho-lunate ligament is recommended, as the incidence of recurrence will be lower, without producing carpal instability. [157] (10.1016/s0363-5023(03)80341-6)
• [Letter] The authors propose that the term midcarpal instability be subclassified into traumatic and nontraumatic categories, as the pathology often involves dissociative ligament disruptions rather than being truly nondissociative. [160] (10.1016/j.jhsa.2022.05.005)
• [L5] [162] (10.1097/bth.0b013e31820e82d2)
• [L4] Although the incidence of carpal bone tunnel collapse is unknown, the consequences could be substantial; therefore, patients should be warned of this possibility when discussing complications of ligament reconstruction for chronic scapholunate instability requiring the creation of a bone tunnel. [166] (10.1016/j.jhsa.2023.07.008)
• [L5] [167] (10.1016/j.otsr.2013.06.015)
• [L5] Midcarpal instability is a term representing multiple distinct entities involving abnormal force transmission across the midcarpal joint. [169] (10.5435/jaaos-d-22-00777)
• [L4] Neither classification is ideal, so the authors propose a new classification that is simple, reproducible, and precise regarding the topography of the lesion on the scapholunate ligament. [174] (10.1016/j.main.2008.12.005)
• [L4] Dorsal wrist capsular impingement is a clinical diagnosis; magnetic resonance imaging may be helpful in evaluating for other pathologies. [178] (10.1016/j.jhsa.2016.12.012)
• [Paper] Long-term clinical prospective trials are needed to examine whether scapholunate dysfunction and osteoarthritic changes are prevented by this capsuloligamentous plicature. [180] (10.1016/j.eats.2024.103424)
• [L4] At 17.9-month average follow-up, radiographic and patient-reported outcome parameters improved after reconstruction of the critical dorsal and volar ligament stabilizers of the proximal carpal row with the ANAFAB technique. [184] (10.1016/j.jhsa.2023.12.012)
• [L4] Radiographic disease progression occurred only in 2 wrist, rated stage IIIB, at 8 and 10 years follow-up without a bad clinical outcome. [187] (10.1016/j.main.2014.10.086)
• [L5] [188] (10.1016/s0266-7681(98)80225-8)
• [L5] At 1 year after surgery, preservation of a normal carpal alignment was noted and there was restoration of a full ROM of the wrist. [191] (10.1016/s0363-5023(05)80184-4)
• [L5] CT scan and MRI scan are indispensable in the investigation of this kind of carpal lesions, allowing better visualization of the base of the tumour, the expansion of the tumour and relation to the neighbouring soft tissues and the presence of malignant degeneration. [193] (10.1016/s1297-3203(01)00024-5)
• [L5] [195] (10.1016/s0363-5023(79)80131-8)
• [L4] [196] (10.1053/jhsu.2003.50035)
• [L3] Cineradiography is a qualitative rather than a quantitative tool, and more research is needed to determine its exact role in diagnosing carpal instability. [197] (10.1177/1753193417694820)
• [L4] [199] (10.2106/00004623-198567030-00013)
• [L5] Trispiral tomography is an important x-ray technique in the diagnosis and management of a variety of problems of the carpal bones and their joints. [200] (10.1016/s0363-5023(88)80044-3)
• [L4] Measurements of carpal bone angles on lateral wrist radiographs can be of assistance in the diagnostic evaluation of wrist malalignment. [203] (10.1016/s0363-5023(10)80156-x)
• [L4] [205] (10.1177/1753193416680133)
• [L4] A positive shift was not correlated with radiographic carpal malalignment. [206] (10.1016/0363-5023(94)90265-8)
• [L3] MRI may be more helpful to exclude potential alternative diagnoses in the patient with ulnar wrist pain. [208] (10.1016/j.jhsa.2013.05.040)
• [L4] Type 2 cases have MRI signal changes involving only part of the scaphoid, commonly report a history of wrist trauma, show fewer tendencies toward scaphoid fragmentation, and may have a more favorable clinical outcome. [209] (10.1016/s0363-5023(03)00260-0)
• [L4] The inconsequent use of available modern magnetic resonance imaging (MRI) techniques and the lack of reliable preoperative diagnoses necessitated pure diagnostic arthroscopies for ulnar-sided wrist pain. [210] (10.1177/1558944716660555hs)
• [L5] Roentgenograms of both wrists are valuable in the evaluation of patients with this condition. [211] (10.1016/s0363-5023(79)80138-0)
• [L4] The authors recommend these nonoperative approaches for appropriate candidates, particularly those with predynamic or dynamic instability. [212] (10.1177/1753193415613050)
• [L2] A scaphoid fracture was by far the most common injury, but it is not clear whether diagnosis of subtle injuries only demonstrated on MRI improves outcomes. [213] (10.1016/j.jhsa.2012.09.034)
• [L5] The patient shows the value of bone technetium scintigraphy and X-ray computerised tomographic scanning of the wrist in patients with persistent and atypical pain in the carpus. [215] (10.1016/0266-7681(89)90098-3)
• [L4] The inherent instability of this injury has a high scaphoid non-union rate and, if identified, treatment by open reduction and internal fixation is recommended. [217] (10.1016/0266-7681(92)90117-k)
• [L4] For patients followed up for an average of 66 months after surgery, the results, clinically and radiographically, appear to deteriorate in those who place high demands on the wrists on a daily basis. [219] (10.1016/j.jhsa.2006.07.005)
• [L4] Follow-up over an average period of 18.1 months in 16 patients showed union in all 16. [221] (10.1016/s0363-5023(87)80273-3)

See Also

• Proximal Row Carpectomy
• Scaphoid Fracture
• Distal Radius Fracture
• Carpal Tunnel Release
• Total Wrist Fusion

References

[1] La luxation péri-lunaire du carpe – à propos de 32 cas. Hand Surgery and Rehabilitation. 2017. DOI: 10.1016/j.hansur.2017.10.201

[2] Green S Operative Hand Surgery. CARPAL INSTABILITY > Classification of Carpal Instability.

[3] Analysis of carpal instability: I. Description of the scheme. The Journal of Hand Surgery. 1995. DOI: 10.1016/s0363-5023(05)80426-5

[4] Treatment of Static Scapholunate Instability With Modified Brunelli Tenodesis: Results Over 10 Years. The Journal of Hand Surgery. 2013. DOI: 10.1016/j.jhsa.2013.02.022

[5] Long-term results of dorsal intercarpal ligament capsulodesis for the treatment of chronic scapholunate instability. The Journal of Bone and Joint Surgery. British volume. 2012. DOI: 10.1302/0301-620x.94b12.30007

[6] Treatment of carpal instability without joint fusion—Current assessment. The Journal of Hand Surgery. 1982. DOI: 10.1016/s0363-5023(82)80138-x

[7] Carpal Ligament Injuries, Pathomechanics, and Classification. Hand Clinics. 2015. DOI: 10.1016/j.hcl.2015.04.011

[9] Degenerative disorders of the wrist. The Journal of Hand Surgery. 1985. DOI: 10.1016/s0363-5023(85)80025-3

[10] Orthopaedic Knowledge Update Trauma. Hand/Carpal Fractures and Dislocations > Scaphoid Fractures > Scaphoid Nonunion.

[11] Arthroscopic Thermal Capsulorrhaphy for Palmar Midcarpal Instability. Journal of Hand Surgery (European Volume). 2007. DOI: 10.1016/j.jhse.2007.03.012

[12] Nouveau traitement de la maladie de Kienböck avancée : remplacement du semi-lunaire par greffon cartilagineux costal. Chirurgie de la Main. 2011. DOI: 10.1016/j.main.2011.04.005

[13] Computed radiography (Fuji) as a diagnostic tool for carpal disease. The Journal of Hand Surgery. 1989. DOI: 10.1016/0363-5023(89)90125-1

[16] Aaos Comprehensive Orthopaedic Review 3. Carpal Instability* > III. Classifications.

[17] Carpal instability, the missed diagnosis in patients with clinically suspected scaphoid fracture. Injury. 1993. DOI: 10.1016/0020-1383(93)90182-6

[18] Midcarpal instability. Journal of Hand Surgery (European Volume). 2015. DOI: 10.1177/1753193415617756

[19] Miller S Review Of Orthopaedics. SECTION 16 PATELLAR TRACKING IN TOTAL KNEE ARTHROPLASTY > 2. Scaphoid fractures > 4. Carpal instability.

[21] Anatomical anterior and posterior reconstruction for scapholunate dissociation: preliminary outcome in ten patients. Journal of Hand Surgery (European Volume). 2019. DOI: 10.1177/1753193419886536

[22] Silastic Implants of the Scaphoid and Lunate. Journal of Hand Surgery. 1993. DOI: 10.1016/0266-7681(93)90223-3

[23] Intercarpal arthrodesis in the management of chronic carpal instability after trauma. The Journal of Hand Surgery. 1984. DOI: 10.1016/s0363-5023(84)80060-x

[25] Scaphocapitate Arthrodesis. Techniques in Hand and Upper Extremity Surgery. 2002. DOI: 10.1097/00130911-200206000-00003

[26] Distal Scaphoid Resection for Arthritis Secondary to Scaphoid Nonunion: A Twenty-year Experience. The Journal of Hand Surgery. 2011. DOI: 10.1016/s0363-5023(11)60002-6

[27] Scapholunate instability: why are the surgical outcomes still so far from ideal?. Journal of Hand Surgery (European Volume). 2023. DOI: 10.1177/17531934221148009

[31] Analysis of carpal instability: II. Clinical applications. The Journal of Hand Surgery. 1995. DOI: 10.1016/s0363-5023(05)80427-7

[32] Green S Operative Hand Surgery. CARPAL INSTABILITY DISSOCIATIVE.

[33] Green S Operative Hand Surgery. AUTHORS' PREFERRED METHOD OF TREATMENT: SL DISSOCIATION > CARPAL INSTABILITY ADAPTIVE (CIA).

[34] Orthopaedic Knowledge Update Trauma. Hand/Carpal Fractures and Dislocations > Summary.

[35] Long-Term Functional Results of a Wrist Exercise Program for Patients with Palmar Midcarpal Instability. Journal of Wrist Surgery. 2017. DOI: 10.1055/s-0037-1612594

[36] Rockwood And Green S Fractures In Adults. 42: Fractures of the Distal Radius and Ulna > Signs and Symptoms of Carpal Fractures and Dislocations.

[37] Scaphocapitate Arthrodesis for Kienböck Disease. The Journal of Hand Surgery. 2015. DOI: 10.1016/j.jhsa.2014.12.013

[38] The Carpal Boss: Review of Diagnosis and Treatment. The Journal of Hand Surgery. 2008. DOI: 10.1016/j.jhsa.2007.11.029

[39] A method for evaluating carpal alignment on lateral radiographs. The Journal of Hand Surgery. 1985. DOI: 10.1016/s0363-5023(85)80087-3

[40] Special issue: the unstable wrist. Journal of Hand Surgery (European Volume). 2015. DOI: 10.1177/1753193415617100

[41] Palmar midcarpal instability: Results of surgical reconstruction. The Journal of Hand Surgery. 1993. DOI: 10.1016/0363-5023(93)90366-b

[42] Management of Complications of Ligament Injuries of the Wrist. Hand Clinics. 2015. DOI: 10.1016/j.hcl.2015.01.003

[43] Rockwood And Green S Fractures In Adults. 42: Fractures of the Distal Radius and Ulna > Carpal Ligament Injuries.

[44] Dorsal Intercarpal Augmentation Ligamentoplasty for Scapholunate Dissociation. Techniques in Hand and Upper Extremity Surgery. 2003. DOI: 10.1097/00130911-200312000-00005

[46] The Late Reduction of Carpal Dislocations. Journal of Hand Surgery. 1992. DOI: 10.1016/0266-7681(92)90073-b

[47] Aaos Comprehensive Orthopaedic Review 3. Carpal Instability* > II. Anatomy and Biomechanics (See Chapter 92).

[48] Green S Operative Hand Surgery. WRIST BIOMECHANICS > Carpal Kinematics.

[50] Rockwood And Green S Fractures In Adults. 42: Fractures of the Distal Radius and Ulna > Pathoanatomy and Applied Anatomy Relating to Carpal Fractures and Dislocations.

[51] Rockwood And Green S Fractures In Adults. 42: Fractures of the Distal Radius and Ulna > Assessment of Radiocarpal Instability.

[52] Miller S Review Of Orthopaedics. CARPAL FRACTURES AND INSTABILITY.

[55] Imaging in carpal instability. Journal of Hand Surgery (European Volume). 2015. DOI: 10.1177/1753193415610515

[56] The Mysterious Wrist. Journal of Hand Therapy. 1996. DOI: 10.1016/s0894-1130(96)80065-2

[58] Chapter 29 Hand/Carpal Fractures and Dislocations. 2021.

[63] Carpal Instability. The Journal of Bone & Joint Surgery. 1995. DOI: 10.2106/00004623-199503000-00019

[64] Aaos Comprehensive Orthopaedic Review 3. Wrist Fractures and Dislocations, Carpal Dissociation, and Distal Radius Fractures > II. Carpal Ligament Injury and Perilunate Dislocation.

[65] Les luxations antélunaires du carpe. À propos de trois cas. Chirurgie de la Main. 2000. DOI: 10.1016/s1297-3203(00)73486-x

[66] Green S Operative Hand Surgery. CARPAL INSTABILITY > Definition.

[67] Proximal row carpectomy for scapholunate dissociation. Journal of Hand Surgery (European Volume). 2010. DOI: 10.1177/1753193410382719

[68] Primary Repair of the Scapholunate Ligament. Techniques in Hand & Upper Extremity Surgery. 1998. DOI: 10.1097/00130911-199812000-00007

[70] Outcome of Distal Radioulnar Joint in Galeazzi Lesions. HAND. 2016. DOI: 10.1177/1558944716660555if

[72] Costo-Osteochondral Grafts in the Wrist. Techniques in Hand & Upper Extremity Surgery. 2001. DOI: 10.1097/00130911-200109000-00008

[73] Management of lunotriquetral instability: a review of the literature. Journal of Hand Surgery (European Volume). 2015. DOI: 10.1177/1753193415595167

[74] Traumatic axial dislocations of the carpus. The Journal of Hand Surgery. 1989. DOI: 10.1016/s0363-5023(89)80003-6

[75] Inside-Out Method to Develop Volar Arthroscopic Portals of the Wrist in Cadaveric Specimens. HAND. 2016. DOI: 10.1177/1558944716660555hr

[76] Green S Operative Hand Surgery. PATHOMECHANICS OF CARPAL LIGAMENT INJURIES.

[77] The role of carpal instability in scaphoid nonunion: Casual or causal?. The Journal of Hand Surgery: Journal of the British Society for Surgery of the Hand. 1986. DOI: 10.1016/0266-7681(86)90260-3

[78] Aaos Comprehensive Orthopaedic Review 3. Wrist Fractures and Dislocations, Carpal Dissociation, and Distal Radius Fractures > I. Carpal Fractures.

[79] Re: Luitjens J, Goller SS, Schmitt R, Erber B, Van Scoonhoven J, Hess N. Diagnostic performance of traditional radiographic indices in detection of carpal collapse in Kienbock’s disease. J Hand Surg Eur. 2023, 48: 619–24.. Journal of Hand Surgery (European Volume). 2023. DOI: 10.1177/17531934231205707

[80] Proximal row carpectomy through volar approach. The Journal of Hand Surgery. 2003. DOI: 10.1016/s0363-5023(03)80411-2

[81] Understanding Midcarpal Instability. The Journal of Hand Surgery. 2006. DOI: 10.1016/j.jhsa.2005.12.014

[82] Carpal Instability. 2021.

[83] Résultats d’une série unicentrique de 17 prothèses de poignet posées entre 2001 et 2011. Chirurgie de la Main. 2012. DOI: 10.1016/j.main.2012.10.043

[85] Cumulative Incidence of Carpal Instability in the Second Year after a Fall onto Outstretched Hand. Journal of Hand Therapy. 2018. DOI: 10.1016/j.jht.2017.11.014

[86] Excisional Arthroplasty for Scaphotrapeziotrapezoidal Osteoarthritis. The Journal of Hand Surgery. 2011. DOI: 10.1016/j.jhsa.2010.12.016

[87] Chapter 24 Carpal Instability. 2019.

[89] Position Statement: Definition of Carpal Instability. The Journal of Hand Surgery. 1999. DOI: 10.1053/jhsu.1999.0866

[104] Green S Operative Hand Surgery. Functional Kinematics and Dart-Thrower’s Motion > Intracarpal Pronosupination.

[108] Green S Operative Hand Surgery. Intrinsic Ligaments > Intercarpal Ligaments.

[109] Rockwood And Green S Fractures In Adults. 42: Fractures of the Distal Radius and Ulna > Neurovascular Anatomy of Carpal Fractures and Dislocations.

[113] A Non-Invasive Method for Studying in Vivo Carpal Kinematics. Journal of Hand Surgery. 1997. DOI: 10.1016/s0266-7681(97)80050-2

[124] A New Method for Radiolunate Arthrodesis in Ulnar Translocation of the Carpus in the Rheumatoid Wrist. Techniques in Hand & Upper Extremity Surgery. 2000. DOI: 10.1097/00130911-200006000-00006

[127] Campbell S Operative Orthopaedics 4 Volume Set. OVERCORRECTION OSTEOTOMY AND LIGAMENTOUS REPAIR OR RECONSTRUCTION > SCAPHOID AND CARPAL FRACTURES.

[131] Arthroscopic-assisted radiocarpal ligaments tensioning for dynamic radiocarpal instability. BMC Musculoskeletal Disorders. 2022. DOI: 10.1186/s12891-021-04857-7

[134] Perilunate Dislocations and Fracture Dislocations. The Journal of Hand Surgery. 2012. DOI: 10.1016/j.jhsa.2012.07.034

[141] Carpal Instability Nondissociative. Journal of the American Academy of Orthopaedic Surgeons. 2012. DOI: 10.5435/00124635-201209000-00004

[143] Outcome of arthroscopic reduction association of the scapholunate joint. Journal of Hand Surgery (European Volume). 2015. DOI: 10.1177/1753193415577335

[145] Modified Viegas dorsal capsuloplasty for chronic partial injury of the scapholunate ligament in young athletes: outcomes at 24 months. Journal of Hand Surgery (European Volume). 2020. DOI: 10.1177/1753193420939490

[146] Green S Operative Hand Surgery. AUTHORS' PREFERRED METHOD OF TREATMENT: SL DISSOCIATION > Carpal Malalignment Secondary to Deformity of the Lunate.

[147] Advanced Carpal Collapse after Longstanding Scaphoid Nonunion (SNAC-Wrist) and Longstanding Scapho-Lunate Dissociation (SLAC-Wrist)—Where are the Differences?. Journal of Hand Surgery. 1994. DOI: 10.1016/0266-7681(94)90353-0

[154] Radiographic Evaluation of the Modified Brunelli Technique Versus the Blatt Capsulodesis for Scapholunate Dissociation in a Cadaver Model. The Journal of Hand Surgery. 2010. DOI: 10.1016/j.jhsa.2010.06.029

[155] Diagnostic performance of traditional radiographic indices in detection of carpal collapse in Kienböck’s disease. Journal of Hand Surgery (European Volume). 2023. DOI: 10.1177/17531934231153966

[156] Traumatic Volar Carpal Instability Nondissociative: A Case Series. Journal of Hand Surgery Global Online. 2023. DOI: 10.1016/j.jhsg.2023.07.001

[157] Occult ganglions of the dorsal scapho-lunate ligament. Histological and long term review of 65 operated cases. The Journal of Hand Surgery. 2003. DOI: 10.1016/s0363-5023(03)80341-6

[160] Letter Regarding “Traumatic Nondissociative Carpal Instability: A Case Series”. The Journal of Hand Surgery. 2022. DOI: 10.1016/j.jhsa.2022.05.005

[162] A Classification-based Treatment Algorithm for Kienböck Disease. Techniques in Hand & Upper Extremity Surgery. 2011. DOI: 10.1097/bth.0b013e31820e82d2

[166] Collapse After Carpal Bone Tunneling: An Underreported Complication?. The Journal of Hand Surgery. 2025. DOI: 10.1016/j.jhsa.2023.07.008

[167] Post-traumatic carpal instability. Orthopaedics & Traumatology: Surgery & Research. 2014. DOI: 10.1016/j.otsr.2013.06.015

[168] Orthopaedic Knowledge Update Trauma. Hand/Carpal Fractures and Dislocations > Perilunate Dislocations and Fracture-Dislocations.

[169] Midcarpal Instability. Journal of the American Academy of Orthopaedic Surgeons. 2023. DOI: 10.5435/jaaos-d-22-00777

[172] Apley And Solomon S Concise System Of Orthopaedics And Trauma. CHRONIC CARPAL INSTABILITY.

[174] Comparaison de deux classifications arthroscopiques pour l’instabilité scapholunaire dissociative. Chirurgie de la Main. 2009. DOI: 10.1016/j.main.2008.12.005

[175] Green S Operative Hand Surgery. AUTHOR'S PREFERRED METHOD OF TREATMENT: ARTHROSCOPIC PARTIAL WRIST FUSION > Carpal Instability.

[178] Diagnosis and Arthroscopic Management of Dorsal Wrist Capsular Impingement. The Journal of Hand Surgery. 2017. DOI: 10.1016/j.jhsa.2016.12.012

[180] Modified Arthroscopic Volar Scapholunate Capsuloligamentous Repair in Chronic Severe but Reducible Volar Scapholunate Instability. Arthroscopy Techniques. 2025. DOI: 10.1016/j.eats.2024.103424

[181] Aaos Comprehensive Orthopaedic Review 3. Carpal Instability* > IV. Evaluation.

[184] One-Year Outcomes of the Anatomical Front and Back Reconstruction for Scapholunate Dissociation. The Journal of Hand Surgery. 2024. DOI: 10.1016/j.jhsa.2023.12.012

[187] Ostéotomie d’accourcissement du capitatum pour les stade IIIA de maladie de Kienböck. Revue d’une série de 10 poignets avec un recul minimum de 5ans. Chirurgie de la Main. 2014. DOI: 10.1016/j.main.2014.10.086

[188] Carpal Boss: Destabilization of the third Carpometacarpal Joint after a Wedge Excision. Journal of Hand Surgery. 1998. DOI: 10.1016/s0266-7681(98)80225-8

[191] Scapholunate ligament disruption in a skeletally immature patient: A case report. The Journal of Hand Surgery. 1997. DOI: 10.1016/s0363-5023(05)80184-4

[193] L'exostose ostéogénique du capitatum. Présentation d'un cas et revue de la littérature. Chirurgie de la Main. 2001. DOI: 10.1016/s1297-3203(01)00024-5

[194] Aaos Comprehensive Orthopaedic Review 3. Carpal Instability* > V. Treatment.

[195] Osteochondroma of the carpal scaphoid. The Journal of Hand Surgery. 1979. DOI: 10.1016/s0363-5023(79)80131-8

[196] The Lichtman classification for Kienböck's disease: An assessment of reliability. The Journal of Hand Surgery. 2003. DOI: 10.1053/jhsu.2003.50035

[197] Wrist cineradiography: a protocol for diagnosing carpal instability. Journal of Hand Surgery (European Volume). 2017. DOI: 10.1177/1753193417694820

[199] The natural history of scaphoid non-union. A review of fifty-five cases.. The Journal of Bone & Joint Surgery. 1985. DOI: 10.2106/00004623-198567030-00013

[200] Trispiral tomography for the evaluation of wrist problems. The Journal of Hand Surgery. 1988. DOI: 10.1016/s0363-5023(88)80044-3

[203] Measurements of carpal bone angles on lateral wrist radiographs. The Journal of Hand Surgery. 1991. DOI: 10.1016/s0363-5023(10)80156-x

[205] Dorsal intercalated segmental instability associated with malunion of a reconstructed scaphoid. Journal of Hand Surgery (European Volume). 2016. DOI: 10.1177/1753193416680133

[206] Scaphoid shift in the uninjured wrist. The Journal of Hand Surgery. 1994. DOI: 10.1016/0363-5023(94)90265-8

[208] Utility of Magnetic Resonance Imaging for Detection of Longitudinal Split Tear of the Ulnotriquetral Ligament. The Journal of Hand Surgery. 2013. DOI: 10.1016/j.jhsa.2013.05.040

[209] Preiser’s disease: identification of two patterns. The Journal of Hand Surgery. 2003. DOI: 10.1016/s0363-5023(03)00260-0

[210] Preventable Repeat Wrist Arthroscopies. HAND. 2016. DOI: 10.1177/1558944716660555hs

[211] Chronic bilateral scapholunate dissociation without symptoms. The Journal of Hand Surgery. 1979. DOI: 10.1016/s0363-5023(79)80138-0

[212] Conservative management of midcarpal instability. Journal of Hand Surgery (European Volume). 2015. DOI: 10.1177/1753193415613050

[213] The Benefit of Magnetic Resonance Imaging for Patients With Posttraumatic Radial Wrist Tenderness. The Journal of Hand Surgery. 2013. DOI: 10.1016/j.jhsa.2012.09.034

[215] Aseptic necrosis of the capitate secondary to gaucher's disease: a case report. The Journal of Hand Surgery: Journal of the British Society for Surgery of the Hand. 1989. DOI: 10.1016/0266-7681(89)90098-3

[217] Scapho-Lunate Dissociation Occurring with Scaphoid Fracture. Journal of Hand Surgery. 1992. DOI: 10.1016/0266-7681(92)90117-k

[219] Outcome After Repair of the Scapholunate Interosseous Ligament and Dorsal Capsulodesis for Dynamic Scapholunate Instability Due to Trauma. The Journal of Hand Surgery. 2006. DOI: 10.1016/j.jhsa.2006.07.005

[221] Wrist arthrodesis using dorsal radial bone graft. The Journal of Hand Surgery. 1987. DOI: 10.1016/s0363-5023(87)80273-3