Lunotriquetral Joint Research Articles

Arthroscopic Repair of Combined Triangular Fibrocartilage Complex, Lunotriquetral Ligament, and Ulnocarpal Ligament Tears

The ulnocarpal ligament complex (UCLC), consisting of the ulnotriquetral, ulnolunate, and ulnocapitate ligaments, plays a pivotal role in maintaining ulnocarpal joint stability and is closely linked to the palmar radioulnar ligament (PRUL), preventing dorsal ulnar translation. Often, tears in the PRUL and UCLC coincide with lunotriquetral interosseous ligament (LTIL) tears as the result of their strong anatomical connections. Biomechanical studies have demonstrated that ulnar-shortening osteotomy enhances stability in the distal radioulnar joint, lunotriquetral joint, and UCLC by tightening the ligaments and capsules. Our technique aims to replicate the effects of ulnar-shortening osteotomy by plicating the volar triangular fibrocartilage complex (TFCC) and capsule, addressing combined TFCC, UCLC, and LTIL pathologies with a single-strand suture approach. Although surgical treatments exist for ulnotriquetral and LTIL tears, addressing concurrent PRUL or palmar TFCC tears has remained a challenge. This article presents a simple technique for managing these complex ulnar wrist pathologies.

Scapholunate and lunotriquetral joint dynamic stabilizers and their role in wrist neuromuscular control and proprioception

Recent research interest has grown in exploring the role of muscles, isometric contraction, proprioception, and neuromuscular control in addressing dynamic scapholunate and lunotriquetral joint instability, marking a shift in the understanding of wrist stability. To present a comprehensive review of the carpal ligaments anatomy and wrist biomechanics, with a particular focus on the role of proprioception in dynamic carpal stability and their role in managing scapholunate (SL) and lunotriquetral (LTq) dynamic instabilities. We conducted a systematic search of the literature and review of the most relevant papers published and indexed in pubmed, related to wrist biomechanics, proprioception and its contribution to carpal dynamic stability. The study involved a comprehensive review of neuromuscular mechanisms in dynamic stabilization of the carpus, based on cadaver studies. The 3D position of the scaphoid, triquetrum, and capitate was monitored before and after tendon loading. The extensor carpi ulnaris (ECU) and the flexor carpi radialis (FCR) are identified as the primary pronators of the midcarpal joint. The ECU's pronation effect can potentially strain the scapholunate ligament, while the supinator muscles, the abductor pollicis longus (APL), the extensor carpi radialis longus (ECRL), and the flexor carpi ulnaris (FCU), have a protective role, particularly in cases of scapholunate ligament dysfunctions. The FCR, despite being a pronator of the distal row, has a beneficial effect as it provokes supination of the scaphoid. Comprehending carpal dysfunctions and instabilities hinges on understanding carpal anatomy and normal biomechanics. Proprioception, encompassing joint position sensation and neuromuscular control, is pivotal for stability. Biomechanical research informs tailored muscle strengthening for specific carpal issues. Supinator muscles should be strengthened for SL injuries, and ECU-focused strengthening and proprioceptive training are key for dynamic LTq instabilities. Ongoing research should delve into the intricate relationship between carpal ligaments, muscles, and proprioception to enhance wrist stability.

Dynamic assessment of scapholunate ligament status by real-time magnetic resonance imaging: an exploratory clinical study

ObjectiveClinical-standard MRI is the imaging modality of choice for the wrist, yet limited to static evaluation, thereby potentially missing dynamic instability patterns. We aimed to investigate the clinical benefit of (dynamic) real-time MRI, complemented by automatic analysis, in patients with complete or partial scapholunate ligament (SLL) tears.Material and methodsBoth wrists of ten patients with unilateral SLL tears (six partial, four complete tears) as diagnosed by clinical-standard MRI were imaged during continuous active radioulnar motion using a 1.5-T MRI scanner in combination with a custom-made motion device. Following automatic segmentation of the wrist, the scapholunate and lunotriquetral joint widths were analyzed across the entire range of motion (ROM). Mixed-effects model analysis of variance (ANOVA) followed by Tukey’s posthoc test and two-way ANOVA were used for statistical analysis.ResultsWith the increasing extent of SLL tear, the scapholunate joint widths in injured wrists were significantly larger over the entire ROM compared to those of the contralateral healthy wrists (p<0.001). Differences between partial and complete tears were most pronounced at 5°–15° ulnar abduction (p<0.001). Motion patterns and trajectories were altered. Complete SLL deficiency resulted in complex alterations of the lunotriquetral joint widths.ConclusionReal-time MRI may improve the functional diagnosis of SLL insufficiency and aid therapeutic decision-making by revealing dynamic forms of dissociative instability within the proximal carpus. Static MRI best differentiates SLL-injured wrists at 5°–15° of ulnar abduction.

Arthroscopic Resection of Lunotriquetral Coalition

Carpal coalition is a rare condition caused by a failure in the process of apoptosis. It is often incidentally diagnosed and seldomly symptomatic. The lunotriquetral joint is the most commonly affected joint, accounting for 90% of carpal coalitions. Minnaar classified the lunotriquetral coalitions into 4 types based on their type, extent, and associated abnormalities. Accurately classifying the coalition requires advanced imaging, and we show an example that includes 2-dimensional and 4-dimensional computed tomography and magnetic resonance imaging. Management of carpal coalitions include nonoperative and operative management. Splinting, anti-inflammatory drugs, hand therapy, activity modification, and steroid injections are all examples of nonoperative management. Operative management of coalitions in the carpus has historically been an arthrodesis whereas in the tarsal bones the gold standard is resection. Arthrodesis has a high complication rate and reduces wrist range of motion, whereas resection retains range of motion and allows the patient to return to activity sooner. We present 2 techniques of treating symptomatic carpal lunotriquetral coalition with arthroscopic resection.

Arthroscopic Wafer Procedure Versus Ulnar Shortening Osteotomy as a Surgical Treatment for Idiopathic Ulnar Impaction Syndrome

To compare clinical and radiologic outcomes and complication rates of the arthroscopic wafer procedure (AWP) and ulnar shortening osteotomy (USO) for idiopathic ulnar impaction syndrome (UIS). From May 2009 to June 2014, 42 patients who were aged 45years or older with idiopathic UIS underwent either the AWP or USO under the following identical surgical indications: (1) less than 4mm of positive ulnar variance, (2) Palmer classification 2C or 2D lesion of the triangular fibrocartilage complex, (3) stable distal radioulnar joint (DRUJ) and/or lunotriquetral joint, and (4) no evidence of osteoarthritis of the DRUJ or ulnocarpal joint. The patient assignment was not randomized. Were used a visual analog scale for ulnar wrist pain; grip strength; range of motion; the Mayo Wrist Score (MWS); and the Disabilities of the Arm, Shoulder and Hand (DASH) score at 3, 6, 12, and 24months after surgery to compare clinical outcomes. Ulnar variance, cystic changes of the lunate and triquetrum, and DRUJ arthritis on radiographs and operation-related complications were compared. This study evaluated 19 patients after the AWP and 23 patients after USO. At 3months, the AWP produced significantly better outcomes than USO regarding grip strength (79.6% ± 14.3% vs 62.7% ± 12.6%, P< .001), MWS (81.8 ± 7.9 points vs 71.3 ± 14.2 points, P= .005), and DASH score (19.4 ± 8.4 vs 31.5 ± 14.0, P= .001); clinical outcomes were similar at 6, 12, and 24months. The complication rates were 34.8% for USO and 10.5% for the AWP; complications included DRUJ arthritis (n= 4), implant irritation (n= 6), and refracture after implant removal (n= 2) in the USO group and secondary surgery (n= 1) and tendinopathy (n= 1) in the AWP group. The AWP and USO for idiopathic UIS with subtle positive ulnar variance achieved similar clinical and radiologic outcomes at 2years after surgery. However, compared with USO, the AWP showed lower complication rates and better grip strength, MWS values, and DASH scores at 3months after surgery. Level III, comparative trial.

Luno-triquetral dissociation – a review of the current literature

Luno-triquetral (LT) joint dissociation is a common cause of ulnar sided wrist pain and our understanding of this entity is still evolving. This article aims to review the current literature regarding the kinematics, pathoanatomy, diagnosis and management of the LT dissociation.

Inestabilidad lunopiramidal

Radial-sided wrist instability has historically received greater attention than ulnar-sided instability despite being a relatively frequent pathology. As a result, there is often a delay in correct diagnosis and appropriate treatment. Lunotriquetral ligament injuries can be partial or complete, and the latter may be associated with injury of secondary stabilisers. When these stabilisers are injured a static carpal instability, known as Volar Intercalated Segmentary Instability (VISI), occurs. Among the most common clinical tests used to detect lunotriquetral instability are the ballottement test, described by Reagan, and the shear test, described by Kleinman, although both of them have a low sensitivity and specificity. Several techniques for the diagnosis of these injuries are used, such as X-rays (usually normal if there is no static instability of the carpus), arthrography and magnetic resonance imaging, although wrist arthroscopy is the reference standard for diagnosing these lesions. There is no consensus about which is the optimal treatment of lunotriquetral ligament tears, as the literature consists mostly of retrospective leveliv studies without standardised objective measurements using validated instruments. Furthermore, most of them describe the results of late treatment due these lesions not usually being diagnosed in an acute phase. Among the treatments described are arthroscopic treatment (debridement/thermal shrinkage/pinning the lunotriquetral joint), open repair of the lunotriquetral ligament, soft tissue reconstruction, and lunotriquetral arthrodesis.

Risk of Injury to the Dorsal Sensory Branch of the Ulnar Nerve With Percutaneous Pinning of Ulnar-Sided Structures

To assess the risk of injury to the dorsal sensory branch of the ulnar nerve (DSBUN) with percutaneous pinning of commonly stabilized ulnar-sided structures. Eleven fresh-frozen cadaveric upper extremities were assessed. Percutaneous pinning of the fifth metacarpal base and neck, lunotriquetral joint, ulnar styloid, and distal radioulnar joint (DRUJ) with 1.4-mm Kirschner wires was performed under fluoroscopic guidance. Each specimen was then carefully dissected and the distance from each pin to the DSBUN was measured using a digital caliper. Direct injury to the DSBUN and pins found immediately adjacent to the nerve were recorded. Mean distance from the pin to the DSBUN at the fifth metacarpal neck was 5.0 ± 1.5 mm; fifth metacarpal base, 2.3 ± 2.2 mm; lunotriquetral joint, 1.8 ± 1.6 mm; ulnar styloid, 0.8 ± 1.1 mm; and DRUJ, 3.1 ± 0.9 mm. Two of 11 ulnar styloid pins and 1 of 11 lunotriquetral pin directly penetrated the DSBUN, whereas 4 of 11 ulnar styloid pins, 3 of 11 fifth metacarpal base pins, and 2 of 11 lunotriquetral pins were directly adjacent to the DSBUN. There was an increased overall risk of DSBUN injury (risk of direct injury and risk of adjacent pin) with pinning of the ulnar styloid compared with fifth metacarpal neck and DRUJ pinning. The current study demonstrates the risk of iatrogenic injury to the DSBUN with percutaneous pinning of the ulnar styloid, lunotriquetral joint, and fifth metacarpal base. We recommend identifying and protecting the nerve to mitigate the risk of iatrogenic injury when performing ulnar-sided pinning of structures from the ulnar styloid to the fifth metacarpal base.

Arthroscopy of the Distal Radioulnar Joint: Its Role in the Evaluation and Management of Ulnar Sided Wrist Pain and the Development of a Classification System for Proximal Partial Thickness Triangular Cartilage Complex Pathology: Level 3 Evidence

Royalty: Arthrex (Boland)Speakers Bureau: Acumed Lecture Fee (Boland) Proximal triangular fibrocartilage complex (TFC) pathology can be underdiagnosed on MRI and a normal radiocarpal view of the TFC does not exclude pathology. The Hypothesis is that pathology exists within the distal radioulnar joint that is not seen on Radiocarpal arthroscopy alone. The aim of the study is to report a retrospective review of findings of DRUJ Arthroscopy and develop a classification system of partial thickness TFC pathology. A retrospective review of all wrist arthroscopic surgery completed by a single surgeon was performed. All cases (94) over a one year period were reviewed and all arthroscopic surgery with a normal TFC on inspection through radiocarpal portals were included. All radiology was reviewed to determine the sensitivity and specificity of MRI in helping diagnose proximal TFC pathology. All radiographs were reviewed to determine if ulnar variance had any impact on the presence of proximal TFC tears. Intraoperative findings were then reviewed and the identified pathology classified into subgroups depending on the location and type of tear. 34 wrist arthroscopies were included all of whom had a normal TFC on radiocarpal arthroscopy. There was no correlation with ulnar variance and the presence of proximal TFC pathology. The sensitivity of MRI in detecting a proximal TFC tear was 70%. A Positive indentation sign was identified in 12 patients with proximal TFC pathology, while sensitivity of this finding is 35% it may be useful indicator that pathology may exist in proximal TFC. Tears were classified according to location on the TFC, they were described as delaminating, flap lacerations or fibrillated. Chondromalacia of the ulnar head and DRUJ stability and lunotriquetral pathology was also assessed and included in the classification. This study highlights the importance of performing distal radioulnar joint arthroscopy. MRI is a useful preoperative investigation but has poor sensitivity in the diagnosis of proximal TFC pathology. Ulnar variance is not predictive of proximal TFC pathology. Proximal TFC pathology frequently exists in the presence of an apparently normal TFC on radiocarpal arthroscopy. Subtle change in the lunotriquetral joint and TFC on radiocarpal arthroscopy that may indicate a proximal TFC pathology. The development of a classification system for describing these proximal TFC pathologies is useful for further clinical and scientific research. We recommend DRUJ arthroscopy as is useful adjunct to wrist arthroscopy and significant pathologies can be identified.

Management of lunotriquetral instability: a review of the literature.

Lunotriquetral ligament injury is a relatively common cause of ulnar-sided wrist pain. Injury ranges from partial stable ligament tears to extensive perilunate instability. Clinical decision-making largely depends on the chronicity, instability and cause of the ligament injury. Conservative treatment is generally regarded as first choice of treatment of mild lunotriquetral instability; however, outcome studies on conservative treatment are lacking. Temporary arthroscopic pinning and/or debridement are minimally invasive procedures of preference. In the case of more dissociative injury, surgical interventions may be performed. The literature suggests that soft tissue reconstruction is an effective procedure in this group. Arthrodesis of the lunotriquetral joint is associated with high rates of non-union (up to 57%) and the indications for surgery should therefore be very clear. Methodological issues make it hard to draw firm conclusions from the data. Studies on the effectiveness of conservative management and prospective comparative studies will further improve clinical decision-making in lunotriquetral instability. N/A.

Arthroscopic Resection of Wrist Ganglion Arising from the Lunotriquetral Joint

The dorsal wrist ganglion is the most common wrist mass, and previous studies have shown that it arises from the scapholunate interval in the vast majority of cases. Treatment has traditionally been open excision, and more recently arthroscopic resection has been established as an effective and less invasive treatment method. However, application of this technique to ganglia in atypical locations has not been reported, where open excision is the usual practice. This report describes two cases of atypical dorsal wrist ganglia that arose from the lunotriquetral (LT) joint, demonstrated by arthroscopic visualization and wrist arthrogram in one of them. Arthroscopic resection was performed, and the application of this technique to a dorsal wrist ganglion with an atypical origin and location is described.

Role of the extensor carpi ulnaris in the stabilization of the lunotriquetral joint. An experimental study

Study designExperimental laboratory-based research in biomechanics. IntroductionThe mechanisms by which some lunotriquetral (LTq) ligament disruptions remain stable are not known. Purpose of the studyTo investigate the contribution of muscles in preventing carpal destabilization when the LTq ligaments are torn. MethodsTen fresh cadaver wrists, set vertical in a jig, were isometrically loaded through five wrist motor tendons. Changes in carpal alignment secondary to the application of loads were monitored by a Fastrak™ electromagnetic motion tracking device, before and after sectioning the LTq ligaments. ResultsAfter LTq ligaments sectioning, wrist loading forced the triquetrum into flexion (5.4° average) and supination (2.9 ). The only muscle capable of extending and pronating the collapsed triquetrum was the extensor carpi ulnaris (ECU). ConclusionsInadequate ECU muscle function is an important destabilizing factor in LTq deficient wrists. Dynamic LTq instabilities may benefit from proprioceptionally training the ECU muscle, while avoiding carpal supination torques. Level of evidenceBasic science study; biomechanics study.

Acute Static Volar Intercalated Segment Instability (VISI) of the Wrist: A Case Report

Introduction: Isolated injuries of the lunotriquetral (LTq) interosseous ligament and associated structures are less common and less well understood than other forms of dissociative carpal instability. For a VISI deformity to occur the LTq interosseous ligament must be disrupted but the progression of lunotriquetral dissociation requires further ligamentous injury, particularly the palmar LTq ligament, and for full dissociation between the lunate and triquetrum, the dorsal radiocarpal ligaments, which finally results in a static volar intercalated segmental instability (VISI) pattern. Case report: A 52-year old left-handed male patient of black origin was presented with a rare pattern of an acute static volar intercalated instability (VISI). Complete disruption of both the intrinsic lunotriquetral ligaments and the dorsal intercarpal ligaments were identified at surgery. Direct repair and dorsal capsulodesis plus temporary pinning of the lunotriquetral joint were carried out. The patient had a good clinical outcome at 2.5 years of follow up despite the persistent static VISI deformity in the last follow up radiographs. Conclusion: This case represents a clinical proof of both anatomical and biomechanical studies that in order for a static VISI deformity to occur (Stage III), not only must the lunotriquetral interosseous ligament and the palmar lunotriquetral ligaments be disrupted but there must also be disruption to the dorsal capsule.

In Brief: Mayfield et al. Classification: Carpal Dislocations and Progressive Perilunar Instability

According to Melsom and Leslie, the earliest description of perilunate dislocation was by Malgaigne in 1855, before the advent of radiography [7]. It later was described by Cousins, Destot, de Quervain, and others [7]. According to Melsom and Leslie [7] Tavernier reported the first series in 1906. Many years later, in 1968, the concept of the proximal row as an intercalated segment was described by Fisk [7]. In 1972, Linscheid et al. [4] modified the concept to develop models of dorsal and volar intercalated instability. The ligamentous pathoanatomy and classification of these injuries, however, had not been well described. In 1980, Mayfield et al. [5] performed a cadaveric study to better delineate the pathoanatomy and classify the degree of carpal instability after perilunate injury. Purpose

Unusual combined fracture dislocation of the wrist and metacarpophalangeal joints: a case report and review of the literature

Volar perilunate fracture dislocation is an extremely rare carpal injury, but associated with metacarpophalangeal joint dislocation of both the ipsilateral index and middle finger has never been reported. We report one case of a 28-year-old man following a high-energy trauma. After performing closed reduction of the metacarpophalangeal joint injury, open reduction of the wrist injury through volar approach was done, and a K-wire fixation was used to stabilize the scaphoid fracture and lunotriquetral joint. After a 16 months' follow-up period, the wrist regained a full range of motion without symptoms, and the fractured bone was strengthened in a good position.

Palmar-divergent dislocation of the scaphoid and the lunate

We describe a patient with palmar-divergent dislocation of the scaphoid and lunate. After successful closed reduction, the scapholunate and lunotriquetral ligaments were sutured through the dorsal approach, and the anterior capsule was sutured through the palmar approach. The scapholunate and lunotriquetral joints were fixed with Kirschner wires for 7 weeks. At the 1-year follow-up, magnetic resonance imaging showed no evidence of avascular necrosis of the scaphoid or lunate, and radiographs showed no evidence of the dorsal and volar intercalated segment instability patterns associated with carpal instability. However, flexion of the scaphoid and a break in Gilula’s line remained. To our knowledge, this is the first report showing treatment of palmar-divergent dislocation of the scaphoid and lunate by suturing the carpal interosseous ligaments.

Intercarpal ligamentous laxity in cadaveric wrists

The purposes of this study were to define the range of laxity of the interosseous ligaments in cadaveric wrists and to determine whether this correlated with age, the morphology of the lunate, the scapholunate (SL) gap or the SL angle. We evaluated 83 fresh-frozen cadaveric wrists and recorded the SL gap and SL angle. Standard arthroscopy of the wrist was then performed and the grades of laxity of the scapholunate interosseous ligament (SLIL) and the lunotriquetral interosseous ligament (LTIL) and the morphology of the lunate were recorded. Arthroscopic evaluation of the SLIL revealed four (5%) grade I specimens, 28 (34%) grade II, 40 (48%) grade III and 11 (13%) grade IV. Evaluation of the LTIL showed 17 (20%) grade I specimens, 40 (48%) grade II, 28 (30%) grade III and one (1%) grade IV. On both bivariate and multivariate analysis, the grade of both the SLIL and LTIL increased with age, but decreased with female gender. The grades of SLIL or LTIL did not correlate with the morphology of the lunate, the SL gap or the SL angle. The physiological range of laxity at the SL and lunotriquetral joints is wider than originally described. The intercarpal ligaments demonstrate an age-related progression of laxity of the SL and lunotriquetral joints. There is no correlation between the grades of laxity of the SLIL or LTIL and the morphology of the lunate, the SL gap or the SL grade. Based on our results, we believe that the Geissler classification has a role in describing intercarpal laxity, but if used alone it cannot adequately diagnose pathological instability. We suggest a modified classification with a mechanism that may distinguish physiological laxity from pathological instability.

Proximal Carpal Row Dislocation: A Case Report

Carpal dislocations commonly occur as the result of high-energy axial loading of the forearm with the wrist extended. There exists several variants of carpal dislocations with the most commonly observed being those about the lunate. Perilunate dislocations and fracture dislocations were first characterized by Mayfield in 1980 and represent a spectrum of traumatic carpal dislocation beginning radial and progressing to the ulnar side of the wrist (Mayfield et al. J Hand Surg [Am] 5:226-241, 1980). The path of energy takes a predictable pattern around the lunate from the scapho-lunate ligament, into the mid-carpal joint and then to the luno-triquetral joint. The final stage is volar dislocation of the lunate into the carpal canal. These complex fracture dislocations are unstable and require operative fixation through open reduction and with internal fixation (Herzberg et al. J Hand Surg [Am] 18:768-779, 1993; Adkison and Chapman Clin Orthop Rel Res 164:199-207, 1982). Other types of carpal dislocations have been described; however, these are much less frequently encountered (Green and O'Brien Clin Orthop Rel Res 149:55-72, 1980; Irwin et al. J Hand Surg [Br] 20B:746-749, 1995; Rosado J Bone Joint Surg 48B:504-506, 1966). These also include mid-carpal instability and longitudinal (axial) instability and have been described extensively in the literature (Norbeck et al. J Hand Surg 12A:509-514, 1987; Primiano and Reef J Bone Joint Surg 56A:328-332, 1974; Garcia-Elias et al. J Hand Surg 14A:446-457, 1989; Taleisnik Hand Clinics 3:51-68, 1987). Carpal instabilities can be characterized as dissociative which disrupt joints within a carpal row, or as non-dissociative which have dislocations or subluxations between carpal rows (Dobyns and Cooney 1998). We report a case of complex carpal injury non-dissociative involving dislocation of the entire proximal carpal row volarly. To our knowledge such a variation of complex carpal dislocation has not been reported. This injury represents yet another possible variant encountered when treating high-energy injuries to the wrist.

Intra- und Interobserver-Reliabilität digital fotodokumentierter Befunde von Handgelenksspiegelungen

The aim of this study was to evaluate the intra- and interobserver reliability of findings in wrist arthroscopies documented by digital photography. 102 consecutive wrist arthroscopies were documented by at least 6 photographs: (1) radioscaphoidal joint with radiopalmar ligaments, (2) scapholunate ligament from radiocarpal, (3) TFCC, (4) lunotriquetral joint with ulnar recessus, (5) scapholunate, and (6) lunotriquetral joint from midcarpal. More photographs were taken of additional pathologies. Arthroscopic findings were documented in an arthroscopy form (synovitis: no/yes, articular effusion: no/yes, cartilage lesion: no/yes). Lesions of the scapholunate ligament were classified according to Geissler, scapholunate and lunotriquetral ligament lesions were graded as partial or complete, TFCC lesions were categorised according to Palmer and trampoline effects noted. Three months later the 6 standard photos and then all photos were re-evaluated by the scoping surgeon and two experienced hand surgeons. Cohen's kappa was used as a measure of agreement between findings three months postoperatively and those in the operation report. Further statistical analyses were done, e. g., to compare intra- and interobserver reliability. In general intraobserver reliability (mean kappa 0.44) was better than interobserver reliability (0.28, 0.30). Assessing all available photos (0.47) did not improve reliability compared to assessing only the six standard photos (0.44). On grading scapholunate ligament lesions as partial or complete the interobserver reliability was fair (0.37, 0.30). Using Geissler's classification the interobserver reliability was κ=0.34 and 0.23. There was substantial intra- (0.61) and interobserver reliability (0.63, 0.60) for cartilage lesions. While intraobserver reliability for TFCC lesions was substantial (0.61), interobserver reliability was only moderate (0.31, 0.48). Even with wrist arthroscopy, the best diagnostic modality for scapholunate ligament, TFCC and carpal cartilage lesions, hand surgeons do not agree in diagnosis and pathology. Therefore, the documentation of arthroscopic findings has to be improved. Digital video documentation of wrist arthroscopy may illustrate wrist pathologies more adequately. However, this still has to be proven by further studies.

Simulated Radioscapholunate Fusion Alters Carpal Kinematics While Preserving Dart-Thrower's Motion

Midcarpal degeneration is well documented after radioscapholunate fusion. This study tested the hypothesis that radioscapholunate fusion alters the kinematic behavior of the remaining lunotriquetral and midcarpal joints, with specific focus on the dart-thrower's motion. Simulated radioscapholunate fusions were performed on 6 cadaveric wrists in an anatomically neutral posture. Two 0.060-in. carbon fiber pins were placed from proximal to distal across the radiolunate and radioscaphoid joints, respectively. The wrists were passively positioned in a custom jig toward a full range of motion along the orthogonal axes as well as oblique motions, with additional intermediate positions along the dart-thrower's path. Using a computed tomography-based markerless bone registration technique, each carpal bone's three-dimensional rotation was defined as a function of wrist flexion/extension from the pinned neutral position. Kinematic data was analyzed against data collected on the same wrist prior to fixation using hierarchical linear regression analysis and paired Student's t-tests. After simulated fusion, wrist motion was restricted to an average flexion-extension arc of 48 degrees , reduced from 77 degrees , and radial-ulnar deviation arc of 19 degrees , reduced from 33 degrees . The remaining motion was maximally preserved along the dart-thrower's path from radial-extension toward ulnar-flexion. The simulated fusion significantly increased rotation through the scaphotrapezial joint, scaphocapitate joint, triquetrohamate joint, and lunotriquetral joint. For example, in the pinned wrist, the rotation of the hamate relative to the triquetrum increased 85%. Therefore, during every 10 degrees of total wrist motion, the hamate rotated an average of nearly 8 degrees relative to the triquetrum after pinning versus 4 degrees in the normal state. Simulated radioscapholunate fusion altered midcarpal and lunotriquetral kinematics. The increased rotations across these remaining joints provide one potential explanation for midcarpal degeneration after radioscapholunate fusion. Additionally, this fusion model confirms the dart-thrower's hypothesis, as wrist motion after simulated radioscapholunate fusion was primarily preserved from radial-extension toward ulnar-flexion.