Association between Extrinsic and Intrinsic Carpal Ligament Injuries at MR Arthrography and Carpal Instability at Radiography: Initial Observations

Assessment of Scapholunate Instability on 4D CT Scans in Patients with Inconclusive Conventional Images

Background Initial imaging work-up using radiography and CT arthrography sometimes can be insufficient to identify a scapholunate (SL) instability (SLI) in patients suspected of having SL ligament tears. Purpose To determine the diagnostic performance of four-dimensional (4D) CT in the identification of SLI and apply the findings to patients suspected of having SLI and with inconclusive findings on radiographs and CT arthrograms. Materials and Methods This prospective single-center study enrolled participants suspected of having SLI (recent trauma, dorsal pain, positive Watson test results, decreased grip strength) between March 2015 and March 2020. Participants with wrist fractures, substantial joint stiffness, or history of wrist surgery were excluded. Each participant underwent radiography, CT arthrography, and 4D CT on the same day. Participants were divided into three groups: those with no SLI, those with SLI, and those with inconclusive results. SL gap and radioscaphoid and lunocapitate angle were measured using semiautomatic quantitative analysis of 4D CT images by two independent readers. Receiver operating characteristic curves were used to evaluate the diagnostic performance of 4D CT. Thresholds were determined with the Youden index and were applied to the inconclusive group. Results Of the 150 included participants (mean age, 41 years ± 14 [SD]; 102 male, 48 female), there were 63 with no SLI, 48 with SLI, and 39 with inconclusive results. The maximum value and range of SL gap measurements on 4D CT scans showed high sensitivity (83% [40 of 48] and 90% [43 of 48], respectively) and high specificity (95% [59 of 62] and 81% [50 of 62], respectively) in the identification of SLI. At least one of these parameters was abnormal on 4D CT scans in 17 of 39 (44%) participants in the inconclusive group, and 10 of 17 (59%) participants had confirmed SLI. In the 22 participants in the inconclusive group with no indication of SLI at 4D CT, follow-up showed no evidence of SLI in 10 (45%) and enabled confirmation of SLI via arthroscopy in three (14%). Conclusion Scapholunate gap measurements on kinematic 4D CT scans enabled correct identification of SLI in 59% of participants with inconclusive results on conventional images. ClinicalTrials.gov registration no. NCT02401568 © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Demehri and Ibad in this issue.

Anatomical and radiological description of ligament insertions on the radial aspect of the scaphoid bone

Anatomical studies on the radial side of the scaphoid mention inter-ligamentous connections, but without detailed description of their relations to one another. The purpose of this study was to provide an anatomical and radiological description of the ligamentous structure on the radial side of the scaphoid. High-field 3-Tesla 3D MRI scans of 7 cadaveric formaldehyde-fixed wrists were performed to assess the presence and location of each ligament. Dissection was performed in 10 wrists under microscopy on the radial side to assess the dimensions, anatomical variations and angles between ligaments in various wrist positions during in intracarpal pronation/supination, flexion/extension and ulnar/radial deviation. This study confirmed that the same ligament configuration was found on MRI and on dissection. The scaphotrapezial ligament, dorsal intercarpal ligament and radial collateral ligament fibers merge along the dorsal ridge of the scaphoid. The fibers of the radial collateral and radioscaphocapitate ligaments could be distinguished in only 4/10 specimens. Wrist position changes from intracarpal pronation to supination produced major changes in angle between the scaphotrapezial and dorsal intercarpal ligaments, while other position changes affected this angle only slightly. 3D MRI sequences allow these structures to be systematically analyzed in case of scapholunate instability. Further studies should be conducted to assess the biomechanical properties of these ligaments and the clinical consequences of isolated injury in this region.

Osteoarthritis of the Wrist: Pathology, Radiology, and Treatment

Osteoarthritis (OA) is a degenerative disease that can manifest in any synovial joint under certain conditions. It leads to destruction of articular cartilage and adjacent bone, as well as formation of osteophytes at the edges of afflicted joint surfaces. Regarding the wrist, typical degenerative arthritis affects particular joints at a specific patient age, due to asymmetric load distribution and repetitive microtrauma. However, in the presence of instability or systemic diseases, early-onset degeneration can also impair the range of motion and grip strength in younger patients. Although advanced stages of OA display characteristic signs in radiography, the detection of early manifestations frequently requires computed tomography or magnetic resonance imaging (in some cases with additional arthrography). If a wrist becomes unstable, timely diagnosis and precise treatment are essential to prevent rapid disease progression. Therefore, close collaboration between radiologists and hand surgeons is obligatory to preserve the carpal function of patients.

Extrinsic and Intrinsic Ligaments of the Wrist

Carpal stability depends on the integrity of both intra-articular and intracapsular carpal ligaments. In this review, the role of the radial-sided and ulnar-sided extrinsic and intrinsic ligaments is described, as well as their advanced imaging using magnetic resonance arthrography (MRA) and contrast-enhanced magnetic resonance imaging (MRI) with three-dimensional (3D) scapholunate complex sequences and thin slices. In the last decade, the new concept of a so-called "scapholunate complex" has emerged among hand surgeons, just as the triangular ligament became known as the triangular fibrocartilage complex (TFCC).The scapholunate ligament complex comprises the intrinsic scapholunate (SL), the extrinsic palmar radiocarpal: radioscaphocapitate (RSC), long radiolunate (LRL), short radiolunate (SRL) ligaments, the extrinsic dorsal radiocarpal (DRC) ligament, the dorsal intercarpal (DIC) ligament, as well as the dorsal capsular scapholunate septum (DCSS), a more recently described anatomical structure, and the intrinsic palmar midcarpal scaphotrapeziotrapezoid (STT) ligament complex. The scapholunate (SL) ligament complex is one of the most involved in wrist injuries. Its stability depends on primary (SL ligament) and secondary (RSC, DRC, DIC, STT ligaments) stabilizers.The gold standard for carpal ligament assessment is still diagnostic arthroscopy for many hand surgeons. To avoid surgery as a diagnostic procedure, advanced MRI is needed to detect associated lesions (sprains, midsubstance tears, avulsions and chronic fibrous infiltrations) of the extrinsic, midcarpal and intrinsic wrist ligaments, which are demonstrated in this article using 3D and two-dimensional sequences with thin slices (0.4 and 2 mm thick, respectively).

Deep Learning-Based Post-Processing of Real-Time MRI to Assess and Quantify Dynamic Wrist Movement in Health and Disease

While morphologic magnetic resonance imaging (MRI) is the imaging modality of choice for the evaluation of ligamentous wrist injuries, it is merely static and incapable of diagnosing dynamic wrist instability. Based on real-time MRI and algorithm-based image post-processing in terms of convolutional neural networks (CNNs), this study aims to develop and validate an automatic technique to quantify wrist movement. A total of 56 bilateral wrists (28 healthy volunteers) were imaged during continuous and alternating maximum ulnar and radial abduction. Following CNN-based automatic segmentations of carpal bone contours, scapholunate and lunotriquetral gap widths were quantified based on dedicated algorithms and as a function of wrist position. Automatic segmentations were in excellent agreement with manual reference segmentations performed by two radiologists as indicated by Dice similarity coefficients of 0.96 ± 0.02 and consistent and unskewed Bland–Altman plots. Clinical applicability of the framework was assessed in a patient with diagnosed scapholunate ligament injury. Considerable increases in scapholunate gap widths across the range-of-motion were found. In conclusion, the combination of real-time wrist MRI and the present framework provides a powerful diagnostic tool for dynamic assessment of wrist function and, if confirmed in clinical trials, dynamic carpal instability that may elude static assessment using clinical-standard imaging modalities.

Interdisciplinary consensus statements on imaging of scapholunate joint instability

Objectives

The purpose of this agreement was to establish evidence-based consensus statements on imaging of scapholunate joint (SLJ) instability by an expert group using the Delphi technique.

Methods

Nineteen hand surgeons developed a preliminary list of questions on SLJ instability. Radiologists created statements based on the literature and the authors’ clinical experience. Questions and statements were revised during three iterative Delphi rounds. Delphi panellists consisted of twenty-seven musculoskeletal radiologists. The panellists scored their degree of agreement to each statement on an eleven-item numeric scale. Scores of ‘0’, ‘5’ and ‘10’ reflected complete disagreement, indeterminate agreement and complete agreement, respectively. Group consensus was defined as a score of ‘8’ or higher for 80% or more of the panellists.

Results

Ten of fifteen statements achieved group consensus in the second Delphi round. The remaining five statements achieved group consensus in the third Delphi round. It was agreed that dorsopalmar and lateral radiographs should be acquired as routine imaging work-up in patients with suspected SLJ instability. Radiographic stress views and dynamic fluoroscopy allow accurate diagnosis of dynamic SLJ instability. MR arthrography and CT arthrography are accurate for detecting scapholunate interosseous ligament tears and articular cartilage defects. Ultrasonography and MRI can delineate most extrinsic carpal ligaments, although validated scientific evidence on accurate differentiation between partially or completely torn or incompetent ligaments is not available.

Conclusions

Delphi-based agreements suggest that standardized radiographs, radiographic stress views, dynamic fluoroscopy, MR arthrography and CT arthrography are the most useful and accurate imaging techniques for the work-up of SLJ instability.

Key Points

• Dorsopalmar and lateral wrist radiographs remain the basic imaging modality for routine imaging work-up in patients with suspected scapholunate joint instability.

• Radiographic stress views and dynamic fluoroscopy of the wrist allow accurate diagnosis of dynamic scapholunate joint instability.

• Wrist MR arthrography and CT arthrography are accurate for determination of scapholunate interosseous ligament tears and cartilage defects.

MRI of the Wrist Ligaments

Technological advances in magnetic resonance imaging (MRI) have improved radiologists' ability to evaluate wrist ligaments. MRI interpretation often guides clinical management. This article aims to review the normal and pathologic appearance of intrinsic and extrinsic wrist ligaments with a focus on MRI. Variant anatomy, imaging pearls, and clinical significance are also discussed. Special attention is paid to key wrist ligaments that play a role in carpal stability.

Imaging of Carpal Instabilities

Background The term “carpal instability” describes different debilitating wrist conditions, in which the carpus is unable to maintain its physiological range of motion and load transfer. Depending on the cause and location of the dysfunction, four groups can be defined: dissociative, non-dissociative, complex, and adaptive carpal instability. As the most common form by far, dissociative carpal instability can further be categorized as dorsal or palmar intercalated segment instability, contingent on the afflicted interosseous ligament.

Method This review article outlines the different entities of carpal instability, their pathophysiology, and their clinical presentation. It further discusses the diagnostic significance of different imaging methods as well as the established treatment options for each form of instability in context with the current literature.

Results and Conclusion Early detection and treatment of carpal instability are essential for preventing carpal osteoarthritis. Traumatic lesions of the scapholunate interosseous ligament are the most frequent cause of instability. They can occur in an isolated fashion or in context with other carpal injuries. While stress imaging and fluoroscopy facilitate the differentiation between dynamic and static forms of carpal instability, only MRI and CT/MR arthrography can directly reveal the extent of ligament discontinuity.

Key Points:

Citation Format

Imaging evaluation of traumatic carpal instability

PURPOSE

To review the epidemiology, pertinent wrist anatomy, classification system, and emergent imaging evaluation of carpal instability with a focus on radiographic assessment of instability.

METHODS

A review of current literature on carpal instability was performed with summary presentation of carpal instability epidemiology, carpal anatomy, imaging evaluation, and classification with imaging evaluation focused on diagnosis in the emergency setting.

RESULTS

Carpal instability is a common pathology in falls on outstretched hand and is likely underdiagnosed due to instability being occult or demonstrating subtle malalignment on static imaging of the wrist. While there is a complex network of intrinsic and extrinsic ligaments contributing to carpal instability, a detailed knowledge of these ligaments is not necessary for radiologists to make an accurate diagnosis in the emergency setting, as identification and classification of carpal instability is based on identification of carpal malalignment patterns on radiography as opposed to identification of specific ligament injuries on advanced imaging. The Mayo classification is the most widely used classification system, which divides carpal instability into four categories: dissociative, non-dissociative, complex, and adaptive. Understanding this classification system allows radiologists to successfully classify almost all carpal instability injuries they will encounter, even in the setting of unusual or rare instability patterns.

CONCLUSION

In working with the treating clinician, it is essential that the emergency radiologist is comfortable with identifying and classifying carpal instability. This will ensure prompt treatment of seemingly benign injuries and those that require intervention, surgical or otherwise, improving the likelihood of a good outcome.

Perilunate injuries: biomechanics, imaging, and classification

Perilunate injuries are uncommon injuries that are often misdiagnosed. Although conventional radiographs can underestimate the severity of the perilunate injuries, assessment with cross-sectional imaging can be complex, and terminology is inconsistent in the scientific literature. The aim of this paper is to describe the biomechanics, anatomy, and classification of perilunate trauma in order to provide a systematic approach to the description and diagnosis of these injuries.

Real-time three-dimensional MRI for the assessment of dynamic carpal instability

Background

Carpal instability is defined as a condition where wrist motion and/or loading creates mechanical dysfunction, resulting in weakness, pain and decreased function. When conventional methods do not identify the instability patterns, yet clinical signs of instability exist, the diagnosis of dynamic instability is often suggested to describe carpal derangement manifested only during the wrist’s active motion or stress. We addressed the question: can advanced MRI techniques provide quantitative means to evaluate dynamic carpal instability and supplement standard static MRI acquisition? Our objectives were to (i) develop a real-time, three-dimensional MRI method to image the carpal joints during their active, uninterrupted motion; and (ii) demonstrate feasibility of the method for assessing metrics relevant to dynamic carpal instability, thus overcoming limitations of standard MRI.

Methods

Twenty wrists (bilateral wrists of ten healthy participants) were scanned during radial-ulnar deviation and clenched-fist maneuvers. Images resulting from two real-time MRI pulse sequences, four sparse data-acquisition schemes, and three constrained image reconstruction techniques were compared. Image quality was assessed via blinded scoring by three radiologists and quantitative imaging metrics.

Results

Real-time MRI data-acquisition employing sparse radial sampling with a gradient-recalled-echo acquisition and constrained iterative reconstruction appeared to provide a practical tradeoff between imaging speed (temporal resolution up to 135 ms per slice) and image quality. The method effectively reduced streaking artifacts arising from data undersampling and enabled the derivation of quantitative measures pertinent to evaluating dynamic carpal instability.

Conclusion

This study demonstrates that real-time, three-dimensional MRI of the moving wrist is feasible and may be useful for the evaluation of dynamic carpal instability.

Anatomy and injuries of the pediatric wrist: beyond the basics

Ligamentous injuries of the pediatric wrist, once thought to be relatively uncommon, are increasingly recognized in the context of acute high-energy mechanism trauma and chronic axial loading, including those encountered in both recreational and high-performance competitive sports. Recent advances in MR-based techniques for imaging the pediatric wrist allow for sensitive identification of these often radiographically occult injuries. Detailed knowledge of the intrinsic and supportive extrinsic ligamentous complexes, as well as normal developmental anatomy and congenital variation, are essential to accurately diagnose injuries to these structures. Early identification of ligamentous injury of the pediatric wrist is essential within the conservative treatment culture of modern pediatric orthopedics because treatment of these lesions often necessitates surgery, and outcomes often depend on early and sometimes aggressive intervention. In this article, we review MR arthrogram technique and pediatric wrist anatomy, and correlate appearances on MR and selected ligamentous pathologies of the pediatric wrist.

Imaging of Wrist Injuries: A Standardized US Examination in Daily Practice

The keys to successful ultrasonography (US) of the wrist include knowledge of the relevant anatomy and understanding the biomechanical aspects. A wide spectrum of pathological findings including bone fractures (scaphoid, triquetrum) and ligament lesions (dorsal intercarpal and radiocarpal ligaments, scapholunate ligament) can be caused by an identical traumatic mechanism determined on the basis of the position of wrist at the time of injury.

In the setting of wrist trauma, an early diagnosis can minimize the potential for inappropriate or delayed treatment. We describe a practical radiological approach by using a standardized imaging protocol: standard radiographs (four views) associated with an US examination focused on seven landmarks. If there is discordance between clinical and radiological features or if the diagnosis of a disruption of the scapholunate ligament remains uncertain, additional cross-sectional imaging (MRI or CT arthrogaphy) should be performed.

[Ligament injuries of the wrist]

The distal radioulnar joint, the triangular fibrocartilage complex (TFCC) and the wrist are stabilized by many ligaments allowing not only a wide range of motion but also providing sufficient stability. The complex arrangement of carpal ligaments and prosupination around the forearm joint enables multiaxial motion patterns. In the wrist, intra-articular ligaments can be differentiated from extra-articular capsular ligaments as well as intrinsic and extrinsic ligament courses. Imaging is essential for classification of dynamic and static instability patterns. This review article illustrates the ligamentous anatomy of the wrist, the symptoms of carpal instability as well as the diagnostic capability of projection radiography, cinematography, computed tomography (CT) arthrography, magnetic resonance imaging (MRI) and MR arthrography.

Treatment of scapholunate ligament injury: Current concepts

Injuries to the scapholunate joint are the most common cause of carpal instability.

An isolated injury to the scapholunate ligament may progress to abnormal joint mechanics and degenerative cartilage changes.

Treatment for scapholunate instability is aimed at arresting the degenerative process by restoring ligament continuity and normalising carpal kinematics.

Early arthroscopic diagnosis of scapholunate injury is mandatory for establishing the prognosis of the injury, as a proper ligament repair is recommended within four to six weeks after trauma.

In this review, anatomy, diagnosis and treatment of scapholunate ligament injury and carpal instability are discussed. Recommendations for treatment based on the stage and classification of injury and the degree of instability and arthritic changes are proposed.

Cite this article: EFORT Open Rev 2017;2:382–393. DOI: 10.1302/2058-5241.2.170016

Dorsal Scaphoid Subluxation on Sagittal Magnetic Resonance Imaging as a Marker for Scapholunate Ligament Tear

PURPOSE

To evaluate the diagnostic utility of scaphoid dorsal subluxation on magnetic resonance imaging (MRI) as a predictor of scapholunate interosseous ligament (SLIL) tears and compare this with radiographic findings.

METHODS

Thirty-six MRIs were retrospectively reviewed: 18 with known operative findings of complete Geissler IV SLIL tears that were surgically repaired, and 18 MRIs performed for ulnar-sided wrist pain but no SLIL tear. Dorsal subluxation of the scaphoid was measured on the sagittal MRI cut, which demonstrated the maximum subluxation. Independent samples t tests were used to compare radiographic measurements of scapholunate (SL) gap, SL angle, and capitolunate/third metacarpal-lunate angles between the SLIL tear and the control groups and to compare radiographic measurements between wrists that had dorsal subluxation of the scaphoid and wrists that did not have dorsal subluxation. Interrater reliability of subluxation measurements on lateral radiographs and on MRI were calculated using kappa coefficients.

RESULTS

Thirteen of 18 wrists with complete SLIL tears had greater than 10% dorsal subluxation of the scaphoid relative to the scaphoid facet. Average subluxation in this group was 34%. Four of 18 wrists with known SLIL tears had no subluxation. No wrists without SLIL tears (control group) had dorsal subluxation. The SL angle, capitolunate/third metacarpal-lunate angle and SL gap were greater in wrists that had dorsal subluxation of the scaphoid on MRI. Interrater reliability of measurements of dorsal subluxation of the scaphoid was superior on MRI than on lateral x-ray.

CONCLUSIONS

An MRI demonstration of dorsal subluxation of the scaphoid, of as little as 10%, as a predictor of SLIL tear had a sensitivity of 72% and a specificity of 100%. The high positive predictive value indicates that the presence of dorsal subluxation accurately predicts SLIL tear.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

Does Total Wrist Arthroplasty for Treatment of Posttraumatic Wrist Joint Osteoarthritis in Young Patients Always Lead to Restriction of High-demand Activities of Daily Living? Case Report and Brief Review of Recent Literature

Background:

Posttraumatic ulnar carpal translocation is a very rare condition that is caused either by fracture-dislocation injury or by purely ligamentous injury of the wrist. Its prognosis is poor and development of posttraumatic pancarpal wrist joint osteoarthritis is inevitable, and options for treatment are total wrist fusion or total wrist arthroplasty.

Methods:

A 24-year-old male sustained a fracture-related injury in his left wrist that was accompanied with a second ligamentous distorsion-related injury 1 year later in the same wrist. Seven years after first injury, a posttraumatic pancarpal wrist joint osteoarthritis has developed that was caused by posttraumatic ulnar carpal translocation. The patient was treated by total wrist arthroplasty with use of the Maestro^TM Wrist Reconstructive System.

Results:

With our patient, it is unclear whether posttraumatic ulnar carpal translocation occurred either as result of the first fracture-related injury or as result of the second ligamentous distorsion-related injury or as result of both injuries. The 31-year-old patient could be reemployed completely in his original occupation as a mechanic for big agriculture machines and load his wrist with more than 10 pounds. In order to preserve motion, the patient reported that he would undergo the same total wrist arthroplasty a second time were it necessary.

Conclusion:

We report on a young male receiving total wrist arthroplasty and resulting in good restoration of his high-demand claims in activities of daily living, respectively. However, it cannot be concluded that total wrist arthroplasty is to be preferred generally over total wrist fusion in young patients. Essential prerequisite for this motion-preserving procedure is the compliance of patients.

Imaging of Sports-related Hand and Wrist Injuries: Sports Imaging Series

Hand and wrist injuries are common occurrences in amateur and professional sports and many of them are sport-specific. These can be divided into two categories: traumatic injuries and overuse injuries. The aim of this article is to review the most common hand and wrist sports-related lesions. Acute wrist injuries are predominantly bone fractures, such as those of the scaphoid, hamate hook, and ulnar styloid. Ligament lesions are more challenging for radiologists and may lead to carpal instability if undiagnosed. Overuse wrist injuries are mainly represented by tendinous disorders, with De Quervain syndrome and extensor carpi ulnaris tendon disorders being the most common among them; however, there are other possible disorders such as impaction syndromes, stress fractures, and neurovascular lesions. Finally, finger lesions, including closed-tendon injuries (mallet and boutonniere injuries, jersey finger, and boxer's knuckle), flexor pulley injuries, and skier's thumb, should also be detected. (©) RSNA, 2016 Online supplemental material is available for this article.

Understanding carpal instability: a radiographic perspective

The wrist is disposed to a variety of instability patterns owing to its complex anatomical and biomechanical properties. Various classification schemes have been proposed to describe the different patterns of carpal instability, of which the Mayo classification is the most commonly used. Understanding the concepts and pertinent terminology of this classification scheme is important for the correct interpretation of images and optimal communication with referring physicians. Standard wrist radiographs are the first line of imaging in carpal instability. Additional information may be obtained with the use of stress radiographs and other imaging modalities.

Imaging in carpal instability

Carpal instability is a complex and heterogeneous clinical condition. Management requires accurate identification of structural injury with an understanding of the resultant movement (kinematic) and load transfer (kinetic) failure. Static imaging techniques, such as plain film radiography, stress views, ultrasound, magnetic resonance, MR arthrography and computerized tomography arthrography, may accurately depict major wrist ligamentous injury. Dynamic ultrasound and videofluoroscopy may demonstrate dynamic instability and kinematic dysfunction. There is a growing evidence base for the diagnostic accuracy of these techniques in detecting intrinsic ligament tears, but there are limitations. Evidence of their efficacy and relevance in detection of non-dissociative carpal instability and extrinsic ligament tears is weak. Further research into the accuracy of existing imaging modalities is still required. Novel techniques, including four-dimensional computerized tomography and magnetic resonance, can evaluate both cross-sectional and functional carpal anatomy. This is a narrative review of level-III studies evaluating the role of imaging in carpal instability.

Cine MRI: a new approach to the diagnosis of scapholunate dissociation

OBJECTIVE

To evaluate the feasibility of cine MRI for the detection of scapholunate dissociation (SLD) and to compare the sensitivity and specificity of cine MRI with those of cineradiography and arthroscopy.

MATERIALS AND METHODS

To evaluate feasibility, healthy subjects underwent cine MRI of the wrist. To evaluate sensitivity and specificity, patients with clinically suspected scapholunate ligament (SLL) injury after trauma to the wrist were prospectively included and underwent radiographic examination, cineradiography, and cine MRI. In 25 out of 38 patients, subsequent arthroscopy was performed. Results of cineradiography and cine MRI correlated with those of arthroscopy.

RESULTS

Cine MRI was of diagnostic quality in all healthy subjects and patients with good interrater agreement. There was excellent correlation between cineradiography and cine MRI. Scapholunate distance differed significantly between healthy subjects and patients with scapholunate dissociation (p < 0.001), but not between imaging modalities in the patient group. Cine MRI had 85% sensitivity and 90% specificity for the detection of SLD.

CONCLUSION

Cine MRI of the wrist is a fast and reliable technique for the detection of SLD with diagnostic accuracy comparable to cineradiography. It can be easily implemented as a routine clinical MRI examination, facilitating diagnostic workup of patients with suspected SLD while avoiding radiation exposure.

Carpal angles as measured on CT and MRI: can we simply translate radiographic measurements?

OBJECTIVE

To determine the reliability of carpal angles measured on CT and MRI compared to radiography and assess if these measurements are interchangeable.

MATERIALS AND METHODS

Our institutional ethic research committee approved this study. For this retrospective study, two independent observers measured the scapholunate (SL), capitolunate (CL), radiolunate (RL), and radioscaphoid (RS) angles on 21 sets of exams, with each set including a radiograph, CT, and MRI of the same wrist. Inter- and intra-observer agreements were evaluated with the intraclass correlation coefficient (ICC). Linear mixed models and two-way contingency tables were used to determine if the angles measured on cross-sectional modalities were significantly different from those obtained on radiography.

RESULTS

Inter-observer agreement was strong (ICC >0.8) for all angles, except for the RL angle measured on MRI (ICC 0.68). Intra-observer agreement was also strong for all angles, except for the CL angle measured on CT (ICC 0.66). SL angles measured on CT and MRI were not statistically different from those measured on radiographs (p = 0.37 and 0.36, respectively), unlike CL, RL, and RS angles (p < 0.05). Accuracy between modalities varied between 76 and 86% for the SL angle and ranged between 43 and 76% for the other angles.

CONCLUSIONS

CL, RL, and RS angles showed large intermodality variability. Therefore, their measurements on CT or MRI could potentially lead to miscategorization. Conversely, our data showing no significant difference between modalities, SL angle could be measured on CT and MRI to assess wrist instability with a lower risk of error.

Real-time magnetic resonance imaging (MRI) during active wrist motion--initial observations

BACKGROUND

Non-invasive imaging techniques such as magnetic resonance imaging (MRI) provide the ability to evaluate the complex anatomy of bone and soft tissues of the wrist without the use of ionizing radiation. Dynamic instability of wrist--occurring during joint motion--is a complex condition that has assumed increased importance in musculoskeletal medicine. The objective of this study was to develop an MRI protocol for evaluating the wrist during continuous active motion, to show that dynamic imaging of the wrist is realizable, and to demonstrate that the resulting anatomical images enable the measurement of metrics commonly evaluated for dynamic wrist instability.

METHODS

A 3-Tesla "active-MRI" protocol was developed using a bSSFP sequence with 475 ms temporal resolution for continuous imaging of the moving wrist. Fifteen wrists of 10 asymptomatic volunteers were scanned during active supination/pronation, radial/ulnar deviation, "clenched-fist", and volarflexion/dorsiflexion maneuvers. Two physicians evaluated distal radioulnar joint (DRUJ) congruity, extensor carpi ulnaris (ECU) tendon translation, the scapholunate (SL) interval, and the SL, radiolunate (RL) and capitolunate (CL) angles from the resulting images.

RESULTS

The mean DRUJ subluxation ratio was 0.04 in supination, 0.10 in neutral, and 0.14 in pronation. The ECU tendon was subluxated or translated out of its groove in 3 wrists in pronation, 9 wrists in neutral, and 11 wrists in supination. The mean SL interval was 1.43 mm for neutral, ulnar deviation, radial deviation positions, and increased to 1.64 mm during the clenched-fist maneuver. Measurement of SL, RL and CL angles in neutral and dorsiflexion was also accomplished.

CONCLUSION

This study demonstrates the initial performance of active-MRI, which may be useful in the investigation of dynamic wrist instability in vivo.

MRI of wrist ligaments

The optimal imaging protocols for magnetic resonance imaging (MRI) of the wrist ligaments are discussed, including the use of magnetic resonance arthrography, and 3 Tesla (T) versus 1.5 T magnetic field strength. The normal MRI appearance of the triangular fibrocartilage complex, capsular, and interosseous wrist ligaments is briefly covered to point out potential diagnostic pitfalls. Numerous examples of common ligamentous pathology discernible on MRI are provided, along with the latest estimates of diagnostic sensitivity and specificity provided by the literature.

A 4D statistical model of wrist bone motion patterns

Direct imaging of ligament damage in the wrist remains a challenge. Still, such damage can be assessed indirectly through the analysis of changes in wrist pose and motion pattern. For this purpose we built a statistical reference model that describes healthy motion patterns. We show that such a model can also be used to detect and quantify pathologies. A model that only describes the global translations and rotations of the carpal bones is insufficiently accurate due to size and shape variations of the bones. We present a local statistical motion model that minimizes the influence of size and shape differences by analyzing the coordinate differences of pairs of points on adjacent bone surfaces. These differences are determined in a set of 14 healthy example wrists imaged in a range of poses by means of 4D-RX imaging. The distribution of the differences as a function of the pose form the local statistical motion model (LSMM). Translations of 2 mm and rotations of 20° with respect to the healthy example wrists are detected as outliers in the point pair distributions. An evaluation involving wrists with a damaged ligament between scaphoid and lunate shows that not only joint space widenings can be detected, but also shifts of congruent bone surfaces. The LSMM is also used to perform a virtual reconstruction of the most likely healthy wrist after a simulated perturbation of bones. The reconstruction precision is shown to be about 1 mm. Therefore, the presented 4D statistical model of wrist bone movement may become a valuable clinical tool for diagnosis and surgical planning.

Midcarpal instability: a radiological perspective

Midcarpal instability (MCI) is the result of complex abnormal carpal motion at the midcarpal joint of the wrist. It is a form of non-dissociative carpal instability (CIND) and can be caused by various combinations of extrinsic ligament injuries that then result in one of several subtypes of MCI. The complex patterns of injury and the kinematics are further complicated by competing theories, terminology and classifications of MCI. Palmar, dorsal, ulna midcarpal instability, and capitolunate or chronic capitolunate instability are all descriptions of types of MCI with often overlapping features. Palmar midcarpal instability (PMCI) is the most commonly reported type of MCI. It has been described as resulting from deficiencies in the ulna limb of the palmar arcuate ligament (triquetrohamate-capitate) or the dorsal radiotriquetral ligaments, or both. Unstable carpal articulations can be treated with limited carpal arthrodesis or the ligamentous defects can be treated with capsulorrhaphy or ligament reconstruction. Conventional radiographic abnormalities are usually limited to volar intercalated segment instability (VISI) patterns of carpal alignment and are not specific. For many years stress view radiographs and videofluoroscopy have been the methods of choice for demonstrating carpal instability and abnormal carpal kinematics respectively. Dynamic US can be also used to demonstrate midcarpal dyskinesia including the characteristic triquetral "catch-up" clunk. Tears of the extrinsic ligaments can be demonstrated with MR arthrography, and probably with CT arthrography, but intact yet redundant ligaments are more difficult to identify. The exact role of these investigations in the diagnosis, categorisation and management of midcarpal instability has yet to be determined.

[Rotatory subluxation of the scaphoid: pathology and surgical management]

The interosseous scapholunate ligament (IOSLL) is the main stabilizer of the scapholunate (SL) couple but a static instability can appear only in the event of an associated injury of the extrinsic ligaments. Thus, SL dissociation covers a broad spectrum in which only static instability leads with certainty to osteoarthritis. Classically described as a rotatory subluxation of the scaphoid with DISI collapse, static SL instability manifests itself as a complex deformity with dorsolateral subluxation of the unit formed by the scaphoid and the distal carpal row. This deformity explains the dorsolateral radioscaphoid conflict and capitolunar decentering that is the origin of the radioscaphoid and midcarpal osteoarthritis that later appears. It is only within the first 4 to 6 weeks that a repair of the IOSLL, possibly associated with a capsulodesis, makes it possible to expect a good result and can prevent osteoarthritis. Beyond that time, no soft tissue procedure will modify the natural history of the condition. For us, surgery is indicated only for acute injuries and for symptomatic chronic instabilities. Before the occurrence of osteoarthritis, with new-found knowledge of the medium-term results of capsulodesis, it seems reasonable to favour a limited fusion. But in the event of failure, the patient is likely to remain in pain even after a total fusion. It is thus not aberrant to perform a capsulodesis in a sedentary person but it is necessary to inform the patient that osteoarthritis will occur. After occurrence of osteoarthritis, if it is symptomatic, proximal row carpectomy, SLAC procedure, total wrist fusion and denervation, can be considered, depending on the stage, the mobility of the wrist and the wishes of the patient. Denervation of the wrist can give good results with few risks, and does not jeopardize the results of a subsequent procedure.

MR arthrography of the wrist: controversies and concepts

Magnetic resonance arthrography (MRA) has become the preferred modality for imaging patients with internal derangement of the wrist. However, several aspects of MRA use need to be clarified before a standardized approach to the imaging of internal derangement of the wrist can be developed. The objective of the study is to evaluate the efficiency of different magnetic resonance (MR) sequences in the detection of lesions of the triangular fibrocartilage complex (TFCC) and scapholunate and lunotriquetral ligaments on direct MRA. Thirty-one consecutive direct magnetic resonance arthrographic examinations of the wrist using a wrist surface coil were performed for the assessment of the TFCC and intrinsic ligaments on a 1.5-T MR imaging system (Signa; 16 channel, Excite, GE Healthcare, Milwaukee, WI, USA). All patients had wrist pain, and in six cases, there was associated clinical carpal instability. The presence, location, and extent of TFCC, scapholunate ligament (SLL), and lunotriquetral ligament (LTL) lesions on T1 fat-saturated, multiplanar gradient recalled (MPGR) and short tau inversion recovery (STIR) images were identified, compared, and analyzed. Forty-one lesions of the TFCC, SLL, and LTL were visualized on contrast-sensitive (T1 fat-saturated) images in 23/31 (74.2%) patients. Twenty-one lesions of the TFCC and intrinsic ligaments were visualized on noncontrast-sensitive (MPGR and STIR) images (15 tears of the TFCC and six tears of the SLL and LTL). All of these lesions were seen on T1 fat-saturated images; 48.8% (20/41) lesions seen on T1 fat-saturated images (eight tears of TFCC and 12 tears of SLL and LTT) were not seen on MPGR and/or STIR images. Superior contrast resolution, joint distention, and the flow of contrast facilitate the diagnosis of lesions of the TFCC and intrinsic ligaments on contrast-sensitive sequences making MRA the preferred modality for imaging internal derangements of the wrist. Little agreement exists regarding the value and location of perforations of the intrinsic ligaments given that both traumatic and degenerative perforations may be symptomatic. Noncommunicating defects of the ulnar attachments of the triangular fibrocartilage (TFC), tears of the dorsal segment of the SLL, and defects at the lunate attachment of the SLL have a higher likelihood of being symptomatic and caused by trauma rather than by degenerative perforation. Although no consensus exists, it would appear that most arthrographies should be started with a radiocarpal injection. Injection into the distal radioulnar joint should be added if no communicational defects are visualized following radiocarpal injection in patients with ulnar-sided wrist pain.

Diagnostic accuracy of plain radiographs and cineradiography in diagnosing traumatic scapholunate dissociation

OBJECTIVE

Missed tears of the scapholunate ligament (SLL) and scapholunate dissociation (SLD) after wrist injuries pose a high risk of post-traumatic osteoarthritis of the carpus. Plain X-rays and dynamic radiographic studies are frequently used for initial diagnostic work-up. Given the limited evidence of their accuracy, we retrospectively compared the radiographic findings of patients with suspected traumatic SLD with wrist arthroscopy as the accepted reference standard.

DESIGN AND METHODS

During a 6-year period, plain radiographs and DSA cineradiography scans were obtained from 198 patients who had sustained a hyperextension injury to their hand. Of those, 102 (72 men, 30 women, mean age of 42+/-12 years) subsequently underwent diagnostic arthroscopy. Digital images were reevaluated by experienced radiologists unaware of the arthroscopic findings for the presence or absence of SLD. We calculated the sensitivity (SN) and specificity (SP) with 95% confidence intervals (CI), and computed areas under the receiver operating characteristic curves (AUC/ROC).

RESULTS

Arthroscopy revealed 42 SLL ruptures, 13, 10, and 19 of which were classified as grade I (partial), II (complete with dynamic instability), or III (complete with static instability) respectively. Plain radiographs correctly identified 24 injuries (SN 57.1%, 95% CI 41.0-72.3%), and produced 1 false-positive result (SP 98.3%, 95% CI 91.1-100.0%). The scapholunate distance and the SL angle contributed independently to the diagnostic variance, with an AUC/ROC of 85.7% (95% CI 76.8-92.2%). Cineradiography had a sensitivity of 36 out of 42 (85.7%, 95% CI 71.5-94.6%), and a specificity of 57 out of 60 (95.0%, 95% CI 86.1-99.0%).

CONCLUSION

Pathological results on plain radiographs and cineradiography reliably indicate the presence of SLD after wrist trauma. Although non-conclusive, a negative dynamic study markedly reduces the pre-test probability of disease. Both methods remain key elements of primary diagnostic strategies for suspected traumatic SLD, and may facilitate the selection of additional tests.

Détermination des conditions d’utilisation d’un mélange contenant un produit de contraste iodé et de l’Artirem® en vue de la réalisation combinée d’une arthro-IRM et d’un arthroscanner

PURPOSE

To determine the influence of 4 independent parameters on signal intensity and density measurements after injection of an arthrography-specific form of gadoterate meglumine and an iodinated contrast material for combined MR and CT arthrography. The parameters included: 1) variations of gadolinium and iodinated contrast agents within the mixture, 2) variations of concentration of the iodinated contrast agent, 3) variation of temperature of the mixture, 4) the type of MR pulse sequence acquired.

MATERIALS AND METHODS

The study was performed on a CT using a phantom containing 47 different syringes. Ten separate mixtures of gadolinium and iodinated contrast agents were obtained, each with a 10% change in the respective proportion of each contrast agent. This was repeated 4 times for 4 iodinated contrast agents of different iodine concentration. Two control syringes, 4 mixtures containing 50% normal saline and 50% iodinated contrast material (one for each of the 4 concentrations of iodinated contrast material) and one with a mixture of 50% of normal saline and gadolinium contrast agent. For the MR acquisition, the syringes were separated into 4 groups for 4 phantoms. On a 1.5 T MR unit, SE T1W, FSE T2W, PD and 3D FIESTA sequences were acquired. All acquisitions were repeated 2 times, and a 3 different temperatures.

RESULTS

The progressive increase in the proportion of gadolinium contrast in the solution was associated with a non-linear increase of signal on T1W, 3D FIESTA, and PD images. The signal intensity reached a plateau at concentrations between 40-60%. Signal variations on the 3D FIESTA sequence were significant. On T2W images, there was an increase of measured signal intensity at low gadolinium concentrations. On CT, there was a linear relationship between density measurements and dilution of gadolinium. The progressive increase of the concentration of the iodinated contrast was associated with increased signal loss on MR and progressive increase of density values on CT. Temperature variations were associated with signal intensity changes on T2W and FIESTA images, but not on T1W images.

CONCLUSION

At 1.5 T, a mixture of 50% iodinated contrast and 50% gadolinium contrast corresponded to an acceptable compromise for combined acquisition of MR and CT arthrography.

The "ulnar fovea sign" for defining ulnar wrist pain: an analysis of sensitivity and specificity

PURPOSE

Eliciting tenderness in the region of the ulnar fovea is a possibly useful clinical test for defining the source of ulnar-sided wrist pain. Until now, no reports of the clinical sensitivity and specificity of this test have been available. Based on anecdotal observations, a hypothesis was developed stating that ulnar fovea tenderness (positive "ulnar fovea sign") is sensitive and specific in detecting two ulnar-sided wrist conditions: foveal disruption of the distal radioulnar ligaments and ulnotriquetral (UT) ligament injuries.

METHODS

The clinical records of 272 consecutive patients with wrist arthroscopy performed by the senior author from 1998 through to 2005 were reviewed. Relevant clinical and surgical data were abstracted. The ulnar fovea sign test is executed by pressing the examiner's thumb distally into the interval between the ulnar styloid process and flexor carpi ulnaris tendon, between the volar surface of the ulnar head and the pisiform. A positive ulnar fovea sign is designated when there is exquisite tenderness that the patient claims replicates their pain, with comparisons made with the contralateral side.

RESULTS

There were a total of 90 foveal disruptions and 68 UT ligament injuries diagnosed during wrist arthroscopy. The ulnar fovea sign was positive in 156 patients. The sensitivity of the fovea sign in detecting foveal disruptions and/or UT ligament injuries was 95.2%. Its specificity was 86.5%.

CONCLUSIONS

The hypothesis stating that the ulnar fovea sign is a useful clinical maneuver to detect foveal disruptions and UT ligament tears is supported. The conditions represent 2 common sources of ulnar-sided wrist pain. The differentiation between the 2 conditions may be made clinically, where UT ligament tears are typically associated with a stable distal radioulnar joint and foveal disruptions are typically associated with an unstable distal radioulnar joint.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

[Early radiological diagnostics for scapholunate dissociation (SLD)]

The partial tear of the scapholunate ligament (pre-dynamic stage of SLD) as well as the complete tear (dynamic stage) does not lead to carpal malalignment. However, if the completely ruptured ligament is accompanied by lesions of the extrinsic ligaments, both the scaphoid and the lunate are malaligned already at rest (static stage of SLD). Later, osteoarthritis will develop, beginning in the radioscaphoid compartment, progressing to the midcarpal joint, and ending in a carpal collapse (osteoarthrotic stage of SLD). Dynamic SLD is detectable only in stress views and in cinematography. The high utility of MRI for directly visualizing the injured ligament is emphasized: reparation tissue is focally enhanced at the rupture site by intravenously applied contrast agent; the individual segments of the scapholunate ligament can be visualized in direct MR arthrography, therefore allowing differentiation of partial and complete ligamentous tears.