MR Imaging of Wrist Ligaments

Imaging Diagnosis and Management of Carpal Trauma and Instability-An Illustrated Guide

Understanding the subtle signs of carpal instability and other unique injury patterns in the wrist is a critical skill for radiologists. Proper patient management and outcomes are directly dependent on the accurate interpretation of wrist imaging studies. This review will provide a detailed overview of typical imaging features of carpal trauma and instability, management, and complications, using multimodality imaging and original medical illustrations. A detailed overview of the osseous, ligamentous, arterial anatomy of the wrist, arcs of Gilula, and zones of vulnerability will be provided. Carpal fractures, dislocations, special radiographic views, and imaging pearls will be discussed. Instability patterns and the myriad of associate abbreviations (CID, CIND, CIC, CIA, VISI, DISI, SLD, LTD, MCI, SLAC, SNAC) will be clarified. Expected outcomes, potential complications, and management will be reviewed.

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.

3D geometric morphometric analysis of the distal radius insertion sites of the palmar radiocarpal ligaments indicates a relationship between wrist anatomy and unique locomotor behavior in hylobatids

OBJECTIVES

The objective of this study is to explore the anatomical differences in the insertion sites of the palmar radiocarpal ligaments between hylobatids and other hominoids that may be related to their different locomotor behaviors.

MATERIALS AND METHODS

The morphology of the insertion sites of the palmar radiocarpal ligaments was analyzed with three-dimensional geometric morphometrics (3D GM) in the distal radial epiphysis of 44 hylobatids, 25 Pan, 31 Gorilla and 15 Pongo.

RESULTS

Relative to other hominoids, hylobatid insertion sites of the palmar radiocarpal ligaments were relatively larger and the insertion site of the short radiolunate ligament had a palmar orientation.

DISCUSSION

Larger palmar radiocarpal ligaments in hylobatids can help stabilize the wrist during the radial and ulnar displacement that occurs in ricochetal brachiation, the characteristic locomotor behavior of hylobatids, and compensate for the large traction loads on the wrist during extended-elbow vertical climbing.

Preoperative and Postoperative Imaging of Scapholunate Ligament Primary Repair and Modified Brunelli Reconstruction

Injury of the scapholunate ligament (SLL) complex can lead to scapholunate dissociation, characterized by scapholunate interval widening and volar rotary subluxation of the scaphoid. Loss of the mechanical linkage between the scaphoid and lunate results in carpal instability and eventual scapholunate advanced collapse (SLAC) arthropathy. SLL complex injuries vary from acute and traumatic to chronic and degenerative. A staging system can be used to guide treatment options for these injuries on the basis of the reparability of the SLL dorsal band, carpal alignment and malalignment reducibility, and cartilage damage. Preoperative imaging with radiography and MRI is a component of injury staging and aids in planning surgical procedures. If the SLL dorsal band is reparable, then direct primary ligament repair with dorsal capsulodesis or dorsal intercarpal (DIC) ligament transfer can be performed. If the SLL dorsal band is irreparable with normal alignment or reducible malalignment, then reconstruction can be performed. In the setting of irreducible malalignment or SLAC arthropathy, a salvage procedure can be performed. Knowledge of SLL primary repair and various reconstruction techniques is important not only when evaluating postoperative images but also for accurate description of SLL injuries and aiding the surgeon in treatment planning. The authors present the normal anatomy of the SLL complex, a staging classification of SLL injury with radiographic and MRI findings, and common surgical procedures. Special attention is given to the operative techniques and postoperative imaging appearances of primary SLL repair with DIC ligament transfer and modified Brunelli reconstruction. ^©RSNA, 2021.

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).

Radiographic characterization of acute scaphoid fractures in children under 11 years of age

BACKGROUND

Delayed diagnosis of scaphoid fractures can lead to long-term morbidity. While radiography is the preferred screening examination, there is a relative paucity of literature that examines fracture visibility in younger children, who have smaller ossification centers, an abundance of unossified cartilage and fractures that preferentially involve the distal scaphoid.

OBJECTIVE

To characterize acute scaphoid fractures in younger children on radiographs with observer agreement and with respect to fracture location.

MATERIALS AND METHODS

This institutional review board (IRB)-approved and Health Insurance Portability and Accountability Act (HIPAA)-compliant cross-sectional study included children (≤10 years of age) with acute scaphoid fractures (≤7 days), who underwent radiographic examinations at a tertiary children's hospital between December 2008 and June 2019. Three readers (two pediatric radiologists and one orthopedic surgeon) reviewed each examination to determine fracture visibility on each radiographic view and fracture location. Kruskal-Wallis, Fisher exact and Cochran-Armitage tests were used to compare fracture visibility and location, and Kappa tests were used to calculate observer agreement.

RESULTS

Twenty-eight children (15 boys, 13 girls; mean age: 9.5±0.6 years) with 10 (36%) distal corner, 11 (39%) distal body and 7 (25%) mid-body fractures, underwent 7 (25%) 4-view, 18 (64%) 3-view and 3 (11%) 2-view examinations. Twenty-six (93%) fractures were visible on at least one view with six (21%) fractures visible on all available views. No significant association was found between fracture visibility and fracture location (P=0.32). Observer agreement was substantial to almost perfect.

CONCLUSION

Only 7% of these acute scaphoid fractures in younger children are inconspicuous on the initial radiographic examination.

Assessing the scapholunate and lunotriquetral interosseous ligament in MR arthrography: Diagnostic advantages of paraxial reformatting

PURPOSE

The scapholunate (SLIL) and lunotriquetral interosseous ligament (LTIL) function as the main stabilizers of the proximal carpal row. Even with MR arthrography, component assessability is often limited in orthogonal standard planes due to their horseshoe-like shape and resulting partial volume effects. This study aims to investigate the diagnostic value of reformatting isotropic 3D sequences with respect to the anatomical orientation of the intrinsic carpal ligaments.

METHOD

In 110 MR arthrograms of the wrist, we investigated the diagnostic accuracy of two radiologists (R1/R2) for SLIL and LTIL injuries in orthogonal standard planes vs. ancillary angulated reformatting of isotropic 3D dual echo steady state sequence. Component assessability and diagnostic confidence were compared between datasets.

RESULTS

The addition of paraxial reformations improved diagnostic accuracy for lesions of the palmar (R1: 0.87 vs. 0.93; R2: 0.86 vs. 0.93; all p < 0.05) and dorsal LTIL (R1: 0.85 vs. 0.93; R2: 0.82 vs. 0.90; all p < 0.05). No significant increase in accuracy could be ascertained for palmar (R1: 0.92 vs. 0.94, p = 0.50; R2: 0.86 vs. 0.92, p = 0.07) and dorsal (R1: 0.95 vs. 0.95, p = 1.00; R2: 0.90 vs. 0.94, p = 0.29) lesions of the SLIL. Interrater reliability was almost perfect with and without angulated planes for SLIL (κ = 0.88 vs. 0.82) and LTIL assessment (κ = 0.88 vs. 0.86). For the LTIL, observer confidence and component assessability were superior with anatomical reformations available (all p < 0.05).

CONCLUSIONS

In contrast to SLIL injuries, diagnosis of LTIL lesions benefits from ancillary paraxial reformations of 3D sequences in MR wrist arthrography.

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.

3T Magnetic Resonance Imaging of the Wrist Tendons

Magnetic resonance imaging (MRI) is frequently used in the imaging evaluation of wrist pain. The complex anatomy of the wrist can be demonstrated by MRI. Three tesla (3 T) MRI offers increased signal-to-noise ratio relative to 1.5 T MRI allowing for higher soft tissue contrast and better spatial resolution. The resulting increase in conspicuity of fine anatomic detail may improve the detection and characterization of wrist pathology. In this article, we will review the anatomy, normal variants, and common pathologies of the wrist tendons as evaluated on 3 T MRI.

Pediatric scaphoid fracture: diagnostic performance of various radiographic views

PURPOSE

The purpose of this study was to systematically investigate the performance of different radiographic views in the identification of scaphoid fractures in children.

METHODS AND MATERIALS

This case-control study compared 4-view radiographic examinations of the wrist between children with scaphoid fracture and age- and sex-matched children without fractures performed between January 2008 and July 2019. After randomization, each examination was reviewed 3 times, at least 1 week apart, first using each view separately and later using multiple views without (3-view) and with the posteroanterior (PA) scaphoid view (4-view), to determine the presence or absence of a scaphoid fracture. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated with inter-rater agreement.

RESULTS

The study group of 58 children (48 boys and 10 girls; mean age 13.1 ± 2.1 years) included 29 with scaphoid fractures (8 corner, 9 distal pole, 10 waist, and 2 proximal pole) and 29 without fractures. Multiple views had higher sensitivity (3-view, 93.0%; 4-view, 96.5%) for fracture identification when compared to individual views (41.0-89.6%). The oblique view was 100% specific for the identification of a scaphoid fracture, but it lacked sensitivity. The PA scaphoid view had the highest sensitivity (89.6%) and NPV (90%) when compared to other individual views and its inclusion in the 4-view examinations produced the highest inter-rater agreement (93%, κ = 0.86).

CONCLUSION

Multiple radiographic views of the wrist with the inclusion of a PA scaphoid view (4-view) produced the highest sensitivity, NPV, and inter-rater agreement for the identification of a scaphoid fracture in children.

Age-dependent changes in pediatric scaphoid fracture pattern on radiographs

OBJECTIVE

To systematically investigate age-dependent changes in scaphoid fracture prevalence and fracture patterns on radiographs in children under 15 years of age.

METHODS AND MATERIALS

This retrospective study included children with scaphoid fractures, who underwent radiographic examinations between May 1, 2009, and August 31, 2019. Blinded to outcome, all radiographs were reviewed to determine fracture visibility on initial radiographs; to characterize fracture location (distal corner, distal, mid, and proximal body) and orientation (horizontal oblique, transverse, and vertical oblique); and to identify the presence or absence of gap, displacement, and concomitant fractures. Demographic information and information on weight and height were collected. Mann-Whitney U, Kruskal-Wallis rank sum, chi-square, and post hoc tests were used to investigate associations between age, fracture characteristics, and BMI percentile.

RESULTS

The study included 180 children (134 boys and 46 girls; 12.3 ± 1.4 years) with 59 (33%) distal corner, 42 (23%) distal, 76 (42%) mid, and 3 (2%) proximal body fractures. Younger children were more likely to present with distal corner and distal body fractures while older children with mid and proximal body fractures (p = 0.035). No association was found between age and fracture visibility (p = 0.246), fracture orientation (p = 0.752), presence of gap (p = 0.130), displacement (p = 0.403), or concomitant fractures (p = 0.588). Younger children with scaphoid fractures were more likely to be obese (n = 117; p = 0.038).

CONCLUSION

Scaphoid fractures of the distal corner and distal body were significantly more common in younger children, who are more likely to be obese.

Patient-Reported Outcome Following Ulnotriquetral Ligament Split Tear Repair

BACKGROUND

While the clinical presentation and mechanism of injury of ulnotriquetral (UT) ligament split tear had been well described, there has been no other studies that has reported on the outcome of a UT ligament repair. This study aims to look at the patient-reported outcomes following UT ligament split tear repair.

METHODS

18 wrists (13 right and 5 left) in 17 patients (12 males and 5 females, mean age 25.0 ± 8.4 years, range 16-50 years) who had UT ligament split tear and undergone surgical repair between November 2007 and December 2013 were retrospectively analysed. Patient-reported outcome of resolution of pain, and objective measurements such as improvement in grip strength and range of movement of the wrist were recorded. Patients were followed up until the pain was completely resolved or the last documented consultation. The mean follow-up duration was 16.2 months.

RESULTS

94% reported improvements post-surgery, of which 63% reported complete resolution of pain. 6% reported no improvement in pain post-operatively. No patient reported worsening of pain after the surgery. There was significant improvement in grip strength from a mean of 23.5 kg to 27.1 kg. There was no significant change in range of motion of the wrist.

CONCLUSIONS

The majority of patients reported resolution or improvement of pain after surgical repair. In addition, there was statistically significant improvement in grip strength recorded.

The Acutely Injured Wrist

Wrist traumas are a frequent clinical emergency for which instrumental imaging assessment is required. The purpose of this article is to review the role of imaging assessment of traumatic wrist injuries, with particular reference to fractures and associated lesions.

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.

MRI and Arthroscopic Correlation of the Wrist

Since its introduction in 1979, the practice of and indications for wrist arthroscopy in the diagnosis and treatment of pathologic conditions in the wrist continues to grow. Magnetic resonance imaging (MRI) is another commonly used tool to noninvasively examine the anatomy and pathology of the wrist joint. Here, we review the normal wrist anatomy as seen arthroscopically and through MRI. We then examine the various common pathologic entities and define both the arthroscopic findings and correlated MRI findings in each of these states.

Inestabilidad lunopiramidal

Históricamente, la inestabilidad en el lado radial de la muñeca ha recibido mucha más atención que la inestabilidad en el lado ulnar, a pesar de ser una patología relativamente frecuente. Como consecuencia de ello, suele darse un retraso en el diagnóstico correcto y el tratamiento apropiado. Las lesiones del ligamento lunopiramidal pueden ser parciales o completas, y estas últimas pueden estar asociadas a lesión de los estabilizadores secundarios. Cuando se lesionan estos estabilizadores es cuando se produce una inestabilidad estática del carpo conocida como Volar Intercalated Segmentary Instability (VISI). Entre los test clínicos más utilizados para detectar una inestabilidad del ligamento lunopiramidal están el Ballottement test, descrito por Reagan, y el Shear test, descrito por Kleinman, aunque ambos poseen una sensibilidad y una especificidad bajas. Para el diagnóstico de estas lesiones se emplean técnicas como la radiografía simple (que suele ser normal si no hay una inestabilidad estática del carpo), la artrografía y la RMN, entre otras, aunque el gold standard lo constituye la artroscopia de muñeca. No existe un consenso en cuanto al tipo de tratamiento óptimo, ya que la mayoría de los estudios publicados son retrospectivos de nivel iv sin medidas objetivas estandarizadas mediante instrumentos validados. Además, en su mayoría describen los resultados del tratamiento tardío, ya que no se suelen diagnosticar en la fase aguda. Dentro de los tratamientos descritos se encuentran el tratamiento artroscópico (desbridamiento/termocoagulación asociados o no a estabilización con agujas de Kirscher), la reparación abierta, la reconstrucción del ligamento y la artrodesis del ligamento lunopiramidal.

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.