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.

Wrist Trauma: More Than Bones

Acute and subacute wrist trauma predominantly consist of fractures of the distal radius in elderly patients and most frequently carpal fractures (scaphoid, followed by triquetrum and hamatum) and avulsion fractures of the ulnar styloid in younger patients, especially in sports-related injuries but also in work activities. The initial radiographs may miss the fractures and result when untreated in complications as nonunion, osteonecrosis, and degenerative osteoarthritis.

Fractures of the distal radius and of the scaphoid may be associated with ligament injuries, most frequently the scapholunate complex, which are often overlooked at the emergency department. Patients without osseous injuries may present intrinsic and extrinsic ligament tears that may lead to carpal instability when they are clinically and/or radiologically missed.

Therefore, in acute and subacute setting, computed tomography may be helpful for the detection of subtle fractures, and magnetic resonance imaging, for the early diagnosis of occult fractures and ligament injuries.

A Case of Short Radiolunate Avulsion Injury: Magnetic Resonance Diagnosis and Surgical Reconstruction

Injury to the volar wrist capsule with short radiolunate ligament avulsion is uncommon and is often difficult to discern on advanced imaging, which can lead to a delay in diagnosis and the development of chronic wrist instability. We report a case of a short radiolunate ligament avulsion injury and a volar wrist capsular injury that went unrecognized for an extended period and led to chronic wrist pain and instability. We describe the magnetic resonance imaging findings of the injury and detail a successful surgical reconstruction technique.

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).

Narrative Review of Ligamentous Wrist Injuries

Ligamentous wrist injuries are common occurrences that require complex anatomical mastery and extensive understanding of diagnostic and treatment modalities. The purpose of this educational review article is to delve into the most clinically relevant wrist ligaments in an organized manner to provide the reader with an overview of relevant anatomy, function, clinical examination findings, imaging modalities, and options for management. Emphasis is placed on elucidating reported diagnostic accuracies and treatment outcomes to encourage evidence-based practice.

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.

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.

[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.

The Role of Dynamic (4D) CT in the Detection of Scapholunate Ligament Injury

Background Scapholunate (SL) interosseus ligament injuries detected at an early stage could allow the surgeon to prevent progression through the spectrum of injury that leads to instability, and eventually osteoarthritis. We contend that early instability following injury can be detected by visualizing the relative motions and distances between the involved carpal bones (scaphoid and lunate) during wrist movement in vivo. The purpose of this study is to demonstrate the utility of dynamic CT (i.e., 4DCT) in diagnosing SL interosseus ligament injuries in two patients with clinical suspicion of SL interosseus ligament injury during flexion-extension (FE), radial-ulnar (RU) deviation, and dart thrower's (DT) motions. Case Description 4DCT images obtained from two individual cases were analyzed to assess the proximity between the scaphoid and lunate during wrist motion using standard image processing techniques. Proximity maps representing the distances between the scaphoid and lunate bones during each phase of wrist motion were determined. These maps provide insight into the severity of diastasis (large separation) and location of diastasis at the SL joint. The patients' proximity maps indicated dorsal diastasis and subtle uniform diastasis. Literature Review Complex musculoskeletal abnormalities, such as wrist joint instabilities, elude diagnosis during 2D fluoroscopy due to the 3D geometry of the anatomy and the inherent 3D nature of the bony kinematics. Even the most recent advances with MR arthrography lack good correlation with wrist arthroscopy. Wrist arthroscopy remains the gold standard for diagnosis to assess for intercarpal laxity. However, arthroscopy is an invasive procedure subjecting patients to the risk of infection, nerve injury, pain, and stiffness. Clinical Relevance 4DCT allows noninvasive characterization of where ligament injuries likely occur; this may allow for a more selective surgical treatment directed at the specific location of the tear.

Magnetic Resonance Arthrography of the Wrist and Elbow

Magnetic resonance (MR) arthrography of the wrist and elbow is useful for detecting a variety of intra-articular pathologies. MR dictations should address whether intrinsic ligament tears of the wrist are partial-thickness or full-thickness, and involve the dorsal, membranous, and/or volar components of the ligaments. With regard to elbow soft tissue pathology, partial-thickness tears of the anterior band of the ulnar collateral ligament in overhead-throwing athletes are well evaluated with MR arthrography. MR arthrography also is helpful in staging osteochondritis dissecans of the capitellum, caused by repetitive valgus impaction injury in adolescent or young adult baseball pitchers.

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.

Advanced imaging of the scapholunate ligamentous complex

The scapholunate joint is one of the most involved in wrist injuries. Its stability depends on primary and secondary stabilisers forming together the scapholunate complex. This ligamentous complex is often evaluated by wrist arthroscopy. To avoid surgery as diagnostic procedure, optimization of MR imaging parameters as use of three-dimensional (3D) sequences with very thin slices and high spatial resolution, is needed to detect lesions of the intrinsic and extrinsic ligaments of the scapholunate complex. The paper reviews the literature on imaging of radial-sided carpal ligaments with advanced computed tomographic arthrography (CTA) and magnetic resonance arthrography (MRA) to evaluate the scapholunate complex. Anatomy and pathology of the ligamentous complex are described and illustrated with CTA, MRA and corresponding arthroscopy. Sprains, mid-substance tears, avulsions and fibrous infiltrations of carpal ligaments could be identified on CTA and MRA images using 3D fat-saturated PD and 3D DESS (dual echo with steady-state precession) sequences with 0.5-mm-thick slices. Imaging signs of scapholunate complex pathology include: discontinuity, nonvisualization, changes in signal intensity, contrast extravasation (MRA), contour irregularity and waviness and periligamentous infiltration by edema, granulation tissue or fibrosis. Based on this preliminary experience, we believe that 3 T MRA using 3D sequences with 0.5-mm-thick slices and multiplanar reconstructions is capable to evaluate the scapholunate complex and could help to reduce the number of diagnostic arthroscopies.

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.

A technique for quantifying wrist motion using four-dimensional computed tomography: approach and validation

Accurate quantification of subtle wrist motion changes resulting from ligament injuries is crucial for diagnosis and prescription of the most effective interventions for preventing progression to osteoarthritis. Current imaging techniques are unable to detect injuries reliably and are static in nature, thereby capturing bone position information rather than motion which is indicative of ligament injury. A recently developed technique, 4D (three dimensions + time) computed tomography (CT) enables three-dimensional volume sequences to be obtained during wrist motion. The next step in successful clinical implementation of the tool is quantification and validation of imaging biomarkers obtained from the four-dimensional computed tomography (4DCT) image sequences. Measures of bone motion and joint proximities are obtained by: segmenting bone volumes in each frame of the dynamic sequence, registering their positions relative to a known static posture, and generating surface polygonal meshes from which minimum distance (proximity) measures can be quantified. Method accuracy was assessed during in vitro simulated wrist movement by comparing a fiducial bead-based determination of bone orientation to a bone-based approach. The reported errors for the 4DCT technique were: 0.00-0.68 deg in rotation; 0.02-0.30 mm in translation. Results are on the order of the reported accuracy of other image-based kinematic techniques.

Imaging of radial wrist pain. I. Imaging modalities and anatomy

Radial wrist pain is a common clinical complaint. The relatively complex anatomy in this region, combined with the small size of the anatomical structures and occasionally subtle imaging findings, can pose problems when trying to localize the exact cause of pain. To fully comprehend the underlying pathology, one needs a good understanding of both radial-sided wrist anatomy and the relative merits of the different imaging techniques used to assess these structures. In part I of this review, these aspects will be discussed.

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.