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MR imaging of normal extrinsic wrist ligaments using thin slices with clinical and surgical correlation
European Journal of Radiology 77 (2011) 196–201
Contents lists available at ScienceDirect
European Journal of Radiology journal homepage: www.elsevier.com/locate/ejrad
Review
MR imaging of normal extrinsic wrist ligaments using thin slices with clinical and surgical correlation M. Shahabpour a,∗ , M. De Maeseneer a , C. Pouders b , L. Van Overstraeten c , P. Ceuterick d , Y. Fierens a , J. Goubau e , J. De Mey a a
Department of Radiology, Universitair Ziekenhuis Brussel, Brussels, Belgium Department of Experimental Anatomy, Vrije Universiteit Brussel, Belgium Department of Foot and Hand Surgery, Centre Hospitalier Régional de Wallonie Picarde, Tournai, Belgium d Department of Hand Surgery, Europa Ziekenhuizen, Brussels, Belgium e Department of Orthopaedic Surgery, UZ Brussel, Brussels, Belgium b c
a r t i c l e
i n f o
Article history: Received 21 April 2010 Received in revised form 25 May 2010 Accepted 28 May 2010 Keywords: MRI extrinsic ligaments Carpal instability Wrist Injuries and wrist
a b s t r a c t Eighty-nine MR examinations of the wrist were retrospectively analyzed. MRI results were compared with clinical findings and/or arthroscopy. Thin proton density and T2 weighted sequences and 3D DESS weighted sequences were applied on a 1.5 T scanner. On the palmar side three radiocarpal ligaments are recognized including the radioscaphocapitate, radiolunotriquetral, radioscapholunate, and midcarpal triquetroscaphoidal ligaments. Ulnocarpal ligaments include the ulnolunate ligament and the ulnotriquetral ligament. On the dorsal side three ligaments are recognized: the dorsal radiolunotriquetral, and the midcarpal triquetroscaphoidal and triquetro-trapezoido-trapezial. The collateral ligaments include the radial and ulnar collateral ligament. MR is a valuable technique in the assessment of the extrinsic and midcarpal ligaments. Depiction of the extrinsic ligaments can best be accomplished with coronal 3D DESS sequences and sagittal and transverse proton density and T2 weighted sequences with thin slices. © 2010 Elsevier Ireland Ltd. All rights reserved.
1. Introduction The extrinsic ligaments likely are as important as the intrinsic ligaments in the setting of carpal instability. Early detection of injuries is necessary for adequate treatment. Lesions of the carpal ligaments often lead either to functional impairment of the wrist (dynamic instability) or to malalignment of the carpal bones (static instability). Initial symptoms are wrist discomfort, grip weakness and click phenomena, which later will progress to limited range of motion and finally to osteoarthritis of the wrist [1–5]. The dorsal radio(luno)triquetral and palmar scapho-trapezoidotrapezial ligaments are secondary stabilizers and when injured are responsible for stage III scapholunate dissociation. Lesions of the palmar arcuate ligament (triquetroscaphoidal ligament) and the dorsal intercarpal ligament (triquetroscaphoidal and triquetrotrapezoido-trapezial ligaments) are responsible for midcarpal
∗ Corresponding author. Department of Radiology, UZ Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium. E-mail addresses: [email protected] (M. Shahabpour), [email protected] (M. De Maeseneer). 0720-048X/$ – see front matter © 2010 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejrad.2010.05.043
instability. MRI and arthroscopy are both imaging methods that allow a direct visualization and analysis of the wrist ligaments. Presently, arthroscopy of the radiocarpal and midcarpal joint is the gold standard in the diagnosis of carpal instability. Wrist arthroscopy however is an invasive technique and is limited by the fact that the dorsal ligaments cannot be visualized due to the dorsal approaches of current wrist arthroscopy. The technique is performed in patients who present with functional discomfort and non-specific radiological and clinical findings, but also when these findings indicate the need for surgery [6,7]. MRI is limited by the oblique or double-oblique course in 3D space of the extrinsic ligaments and image interpretation needs to be based on the sum of adjacent thin MR slices. In our practice, we are able to analyze the ligaments based on images obtained in the three orthogonal planes. The main objective of the examination of the ligaments is to recognize injuries with an unfavourable prognosis that require a specific treatment. A few correlative studies between MRI and arthroscopy (usually with a limited number of patients) have been published about the intrinsic ligaments (especially the scapholunate ligament) [8]. A very limited amount of studies focus on the extrinsic ligaments. The purpose of this work is to describe the normal anatomy of the extrinsic ligaments, based on correlations with arthroscopy and clinical findings.
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Table 1 Overview of extrinsic and midcarpal ligaments. Palmar Radiocarpal Radioscaphocapitate Palmar radiolunotriquetral (radiolunate/palmar lunotriquetral) Radioscapholunate Midcarpal Palmar triquetroscaphoidal (arcuate) Scaphotrapeziotrapezoidal Ulnocarpal Ulnotriquetral Ulnolunate Dorsal Radiocarpal Dorsal radio(luno)triquetral Midcarpal Dorsal intercarpal (dorsal triquetroscaphoidal and triquetrotrapezoidotrapezial)
2. Materials and methods Our work is based on the retrospective analysis of eighty-nine MR examinations of the wrist. In some cases, an MR examination of the contralateral asymptomatic wrist was also obtained. These patients presented with chronic middorsal or midpalmar pain. MRI findings were correlated with clinical outcome or with arthroscopy [7]. A 1.5 T Symphony Vision (Siemens, Erlangen, Germany) was used. Proton density and T2 weighted sequences were performed with the following imaging parameters: TR/TE, 4000/13, 4000/77; slice thickness, 2 mm; slice interval, 0.2 mm; number of acquisitions, 1; FOV, 100 × 100; matrix size, 256 × 256. 3D DESS (dual echo with steady-state precession) sequences were obtained with the following parameters: TR/TE, 23/9; flip angle, 25◦ ; slice thickness, 1 mm; number of acquisitions, 1; FOV, 100 × 100; matrix size, 256 × 256. Cadaveric images were studied for anatomical correlation. 2.1. Pictorial essay In this work we describe the normal MR appearance of radiocarpal and ulnocarpal extrinsic ligaments. Our work is based on anatomic descriptions in the medical literature, cadaveric studies, MR imaging, and arthroscopic and clinical correlation. An overview of the ligaments is given in Table 1. The extrinsic ligaments join the distal end of radius or ulna to carpal bones (while the intrinsic ligaments arise and insert on carpal bones). The anatomy of the extrinsic ligaments is complex. They are intracapsular and encompass radiocarpal ligaments (between the radius and the carpal bones) and ulnocarpal ligaments (between the ulna and the carpal bones). All the radiocarpal ligaments are proximally attached to the distal part of the radius and insert distally on one or more carpal bones. They represent areas of capsular thickening. Their orientation is usually oblique and hence several adjacent thin slices are necessary to analyse the entirety of the ligaments. The ligaments present a fasciculated and striated morphology with alternating bands of hypointense and hyperintense signal intensity [9–11]. Several extrinsic ligaments are described at the level of the palmar and dorsal parts of the carpus. Palmar ligaments are thicker and stronger than dorsal ligaments. They are important stabilizers of wrist movements [12–15]. Although there are several variations of the description of the ligaments, we recognize two groups on the palmar side (with a V-
Fig. 1. Cadaveric dissection (courtesy of David Connell, London, UK). Note the radiolunate (RL), palmar lunotriquetral (LT), and radioscaphocapitate (RSC) ligaments. Normal interruption of fibers is seen at the lunate attachment of RL and LT ligaments (arrow).
shape), and a group with a transverse orientation (with a reversed V-shape) on the dorsal side. 2.1.1. Palmar radiocarpal ligaments On the palmar side, three strong extrinsic radiocarpal ligaments are clearly identified: the radioscaphocapitate, long radiolunate, and radioscapholunate ligaments (Figs. 1–5). The radioscaphocapitate ligament (RSC) originates from the styloid process of the radius (Figs. 1–5). It overlies the waist of the scaphoid (maintaining the position of the scaphoid as it acts like a seat belt). It inserts on the palmar side of the capitate. It acts like a spindle around which the scaphoid revolves and is fundamental for scaphoid stability [16–20].
Fig. 2. 3DESS sequence with 1 mm thick slice. Note radiolunate (RL), palmar lunotriquetral (LT), and radioscaphocapitate (RSC) ligaments. L, lunate; R, radius.
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Fig. 3. Drawing. Illustration shows radioscaphocapitate (RSC), radiolunate (RL), and palmar lunotriquetral (LT) ligaments. Also note radioscapholunate ligament (RSL) and the inconstant short radiolunate (RLC).
Fig. 5. T2 weighted MR image with 2 mm thick slice. Normal radioscaphocapitate ligament (arrow).
Fig. 4. Arthroscopic view. Note radiolunate (RL) and radioscaphocapitate (RSC) ligaments. Interligamentous sulcus is seen between the two ligaments (arrow).
The palmar radiolunotriquetral ligament (RLT) or long radiolunate ligament courses parallel to the radioscaphocapitate ligament (Figs. 1–4). It originates from the palmar margin and from the styloid process of the radius and courses to the radial margin of the palmar surface of the lunate. It then courses obliquely to the palmar side of the triquetrum. It is covered by the ulnotriquetral ligament at this site. The fibers of the RLT may be interrupted at the lunate attachment and hence two distinct ligaments are present: the long radiolunate and the palmar lunotriquetral. The RLT ligament is the longest ligament of the wrist [21–24]. The radioscapholunate ligament (or ligament of Testut) originates between the long and the short portions of the radiolunate ligament (Figs. 3 and 6). Its fibers are embedded in the interosseous scapholunate ligament. It is located deeper than the RSC and RLT ligaments. It rather represents a synovial fold which retains a neurovascular bundle. At arthroscopy it serves as a reference to point
Fig. 6. Proton density weighted MR image with 2 mm thick slice. Normal radioscapholunate ligament (RSC) (arrow).
out the scapholunate ligament [25,26]. These three palmar ligaments can be visualized at arthroscopy. At arthroscopy only the short intra-articular part is visible. The short radiolunate ligament, which is not described by all the researchers, is close to the palmar fibers of the triangular fibrocartilaginous complex (Fig. 3). It is a palmar capsular thickening. Its origin is on the palmar and ulnar rim of the distal part of the radius and the ligament inserts on the proximal part of the palmar surface of the lunate. This ligament stabilizes the lunate [27]. The midcarpal triquetro(capito)scaphoidal ligament (arcuate ligament) has an oblique course deep in the carpal tunnel and is
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Fig. 7. Transverse proton density weighted image. The arcuate (palmar triquetroscaphoidal) ligament is seen deep in the carpal tunnel (arrows).
Fig. 9. Proton density weighted image with 2 mm thick slice. Note ulnolunate ligament (arrow).
Fig. 10. Proton density weighted image with 2 mm thick slice. Note anterior insertion of ulnotriquetral ligament (arrow). Fig. 8. Drawing. Palmar ulnolunate (UL) and ulnotriquetral (UT) ligaments are attached to triangular fibrocartilage (TFC).
visible on almost all tranverse MR scans of the wrist. It plays an important role in the pathogenesis of midcarpal instability (Fig. 7) [28]. 2.1.2. Ulnocarpal ligaments The proximal palmar ligament group (with a V-shape) is made up of the extrinsic ulnotriquetral and ulnolunate ligaments on the medial side, and of the extrinsic radiolunotriquetral ligament on the lateral side (Fig. 8). This group stabilizes the lunate and hence the proximal row of the carpal bones. The ulnocarpal ligaments originate on the palmar rim of the triangular fibrocartilage and the base of the styloid process of the ulna. The ulnolunate ligament is located adjacent to the short radiolunate ligament (Fig. 9). It follows a similar course, and inserts on the palmar side of the lunate. The ulnotriquetral ligament inserts on the triquetrum [20,29–31] (Figs. 9 and 10). The ulnotriquetral ligament has a dorsal and a palmar bundle. The ligament is located in close
Fig. 11. 3D DESS sequence with 1 mm thick slice. Note anterior insertion of the palmar ulnotriquetral ligament (arrow) on the TFC.
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Fig. 14. Same cadaveric specimen. Note dorsal radiotriquetral (RT), triquetroscahoidal (TS), and triquetrotrapezoidotrapezial ligaments (TT).
Fig. 12. Drawing. Note dorsal radiotriquetral (RT) ligament. Also note two mediocarpal ligaments: the triquetroscaphoidal (TS), and triquetro-trapezoido-trapezial (TT) or dorsal intercarpal ligament. CR, radial collateral ligament; CU, ulnar collateral ligament.
proximity to the meniscus homologue and both may be difficult to differentiate. In our experience the meniscus homologue can only be well visualized with MR arthrography (Fig. 11). 2.1.3. Dorsal radiocarpal ligaments Dorsal ligaments (Fig. 12) are thinner and biomechanically less important than palmar ligaments. The dorsal radiolunotriquetral ligament (Fig. 13) (radiocarpal ligament) is the main extrinsic ligament, originating from the distal radius (at the level of Listers’
tubercle and/or the styloid process of the radius) to the lunate and the triquetrum. Several intrinsic midcarpal dorsal ligaments link the carpal bones. Among these ligaments, the dorsal intercarpal ligament (Figs. 12–14), which includes the triquetroscaphoidal and the triquetro-(trapezoido)-trapezial [27,31–34]. The dorsal ligamentous group which has a transverse orientation (with a reversed V-shape) is composed of these ligaments. They also participate in the stability of the proximal row of the carpus. According to the arthroscopic correlation study performed by Scheck et al in 20 patients who underwent surgery and were examined with MRI or with MR arthrography, radiocarpal ligaments can not be accurately analysed on MRI, even with thin slices [8,35]. According to our experience, ligaments could be depicted on MRI, especially when using intravenous injection of contrast [30–31]. The hyperemia of the surrounding synovia allows a better visualisation of the extrinsic ligaments [36].
Fig. 13. Cadaveric specimens (A and B) 3D DESS sequence with 1 mm thick slice. Note extrinsic radiotriquetral ligament in A (arrow). Note radiotriquetral ligament (RT) and midcarpal triquetroscaphoidal (TS) and triquetrotrapezoidotrapezial ligament (TT) in B.
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2.1.4. Collateral ligaments Collateral ligaments of the wrist correspond to thickened areas of the fibrous capsule. These ligaments can be seen at arthroscopy but may be difficult to visualize on MRI. They do not play an important role in wrist instability, but may be a cause of pain when injured. Their function is less important than those of the knee or elbow. The radial collateral ligament is a dorsal extension of the palmar radioscaphoidal ligament and originates from the apex of the styloid process of the radius to insert itself to the scaphoid waist. The ulnar collateral ligament reinforces the palmar ulnotriquetral ligament and originates proximally from the base and to the body of the styloid process of the ulna (with an extension towards the triangular fibrocartilage of the carpus). It inserts distally to the triquetrum and to the pisiform [29]. In conclusion, in our experience the extrinsic ligaments can be well visualized with the sequences described earlier including coronal 3D DESS, and sagittal and axial proton density and T2 weighted images. 3D DESS sequences with reconstructions in the three orthogonal planes can also be valuable when available on the MR system. It is important to analyze all imaging planes to obtain a complete view of the ligaments given the oblique course of many ligaments. References [1] Linscheid RL, Dobyns JH, Beabout JW, Bryan RS. Traumatic instability of the wrist: diagnosis, classification and pathomechanics. J Bone Joint Surg 1972;54A:1612–32. [2] Trail IA, Stanley JK, Hayton MJ. Twenty questions on carpal instability. J Hand Surg Eur Vol 2007;32:240–55. [3] Schmitt R, Frochner S, Coblenz G, Christopoulos G. Carpal instability. Eur Radiol 2006;16:2161–78. [4] Theumann NH, Etechami G, Duvoisin B, et al. Association between extrinsic and intrinsic carpal ligament injuries at MR arthrography and carpal instability at radiography: initial observations. Radiology 2006;238:950–7. [5] Adler BD, Logan PM, Janzen DL, et al. Extrinsic radiocarpal ligaments: magnetic resonance imaging of normal wrists and scapholunate dissociation. Can Assoc Radiol J 1996;47:417–22. [6] Roulot E. Arthroscopie du poignet. In: Godefroy, et al., editors. Intérêt diagnostique et thérapeutique dans Imagerie du poignet et de la main. Paris: Sauramps Médical; 2001. [7] Dautel G, Et Blum A. In: Godefroy, et al., editors. Place de l’arthroscanner et de l’arthroscopie dans le diagnostic des instabilités du poignet dans Imagerie du poignet et de la main. Paris: Sauramps Médical; 2001. [8] Scheck RJ, Romagnolo A, Hierner R, Pfluger T, Wilhelm K, Hahn K. The carpal ligaments in MR arthrography of the wrist: correlation with standard MRI and wrist arthroscopy. J Magn Reson Imaging 1999;9:468–74. [9] Shahabpour M, Allemon B, Kichouh M, Ceuterick P, De Maeseneer M, De Mey J. MR imaging of volar radiocarpal and ulnocarpal ligamentous lesions using thin slices with clinical and surgical correlation. In: Poster Presented at RSNA. 2008. [10] Totterman SM, Miller R, Wasserman B, Blebea JS, Rubens DJ. Intrinsic and extrinsic carpal ligaments: evaluation by three-dimensional Fourier transform MR imaging. AJR 1993;160:117–23. [11] Brown RR, Fliszar E, Cotten A, Trudell D, Resnick D. Extrinsic and intrinsic ligaments of the wrist: normal and pathologic anatomy at MR arthrography with three-compartments enhancement. Radiographics 1998;18:667–74.
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[12] Viegas SF, Patterson RM, Hokanson JA, Davis J. Wrist anatomy: incidence, distribution, and correlation of anatomic variations, tears, and arthrosis. J Hand Surg [Am] 1993;18:463–75. [13] Viegas SF, Patterson RM, Ward K. Extrinsic wrist ligaments in the pathomechanics of ulnar translation instability. J Hand Surg 1995;20A:312–8. [14] Feipel V, Rooze M. The capsular ligaments of the wrist: morphology, morphometry and clinical applications. Surg Radiol Anat 1999;21:175–80. [15] Smith DK. Volar carpal ligaments of the wrist: normal appearance on multiplanar reconstructions of three-dimensional Fourier transform MR imaging. Am J Roentgenol 1993;161:353–7. [16] Taleisnik J. The ligaments of the wrist. J Hand Surg 1976;1:110–8. [17] Berger RA, Landsmeer JM. The palmar radiocarpal ligaments: a study of adult and fetal human wrist joints. J Hand Surg [Am] 1990;15:847–54. [19] Reicher M. Normal wrist anatomy, biomechanics, basic imaging protocol, and normal multiplanar MRI of the wrist. In: Reicher MA, editor. MRI of the wrist and hand. New York, NY: Raven; 1990. pp. 17–48. [20] Theumann NH, Pfirrmann CW, Antonio GE, Chung CB, Gilula LA, Trudell DJ. Extrinsic carpal ligaments: normal MR arthrographic appearance in cadavers. Radiology 2003;226:171–9. [21] Smith DK. Volar carpal ligaments of the wrist: normal appearance on multiplanar reconstructions of three-dimensional Fourier transform MR imaging. AJR 1993;161:353–7. [22] Rominger MB, Bernreuter WK, Kenney PJ, Lee DH. MR imaging of anatomy and tears of wrist ligaments. RadioGraphics 1993;13:1233–46. [23] Timins ME, Jabnke JP, Krah SF, Erickson SJ, Carrera GE. MR imaging of the major carpal stabilizing ligaments: normal anatomy and clinical examples. RadioGraphics 1995;15:575–87. [24] Boutry N, Lapegue F, Masi L, Claret A, Demondion X, Cotton A. Ultrasonographic evaluation of normal extrinsic and intrinsic carpal ligaments: preliminary experience. Skeletal Radiol 2005;34:513–21. [25] Berger RA, Kauer JM. Radioscapholunate ligament: a gross anatomic and histologic study of fetal and adult wrists. J Hand Surg [Am] 1991;16: 350–5. [26] Connell D, Page P, Wright W, Hoy G. MRI of the wrist ligaments. Australas Radiol 2001;45:411–22. [27] Resnick D, Kang HS, Pretterklieber ML. Wrist and hand in internal derangements of joints, vol. 1, 2nd ed. Philadelphia: Saunders; 2007, 1218– 1418. [28] Chang W, Peduto AJ, Aguiar ROC, Trudell DJ, Resnick DL. Arcuate ligament of the wrist: normal MR appearance and its relationship to palmar midcarpal instability: a cadaveric study. Skeletal Radiol 2007;36:641–5. [29] Tanaka T, Ogino S, Yoshioka H. Ligamentous injuries of the wrist. Semin Musculoskelet Radiol 2008;12:359–78. [30] Shahabpour M, Allemon B, Ceuterick P, et al. Anatomie normale et lésionnelle des ligaments extrinsèques en IRM. La chirurgie ligamentaire du carpe avant l’arthrose. Montpellier–Paris: Sauramps Médical, Montpellier–Paris; 2009. pp. 75–84. [31] Shahabpour M, Ceuterick P, Allemon B, et al. IRM des ligaments extrinsèques du carpe. Poignet et main. Montpellier–Paris: Sauramps Médical; 2009. p. 419–431. [32] Smith DK. Dorsal carpal ligaments of the wrist: normal appearance on multiplanar reconstructions of three-dimensional Fourier transform MR imaging. AJR 1993;161:119–25. [33] Mitsuyasu H, Patterson RM, Shah MA, Buford WL, Iwamoto Y, Viegas SF. The role of the dorsal intercarpal ligament in dynamic and static scapholunate instability. J Hand Surg Am 2004;29:279–88. [34] Sarazin L, Godefroy D, Rousselin B, Drapé JL, Chevrot A. Imagerie par résonance magnétique du poignet et de la main dans les situations normales. In: Atlas anatomique. Encycl Méd Chir. Paris: Elsevier SAS; 2005. [35] Scheck RJ, Kubitzek C, Hierner R, et al. The scapho-lunate interosseous ligament in MR arthrography of the wrist: correlation with non-enhanced MRI and wrist arthroscopy. Skeletal Radiol 1997;26:263–71. [36] Hajek PC, Sartoris DJ, Gylys-morin V, et al. The effect of intra-articular gadolinium-DTPA on synovial membrane and cartilage. Invest Radiol 1990;25:179–83.
Contents lists available at ScienceDirect
European Journal of Radiology journal homepage: www.elsevier.com/locate/ejrad
Review
MR imaging of normal extrinsic wrist ligaments using thin slices with clinical and surgical correlation M. Shahabpour a,∗ , M. De Maeseneer a , C. Pouders b , L. Van Overstraeten c , P. Ceuterick d , Y. Fierens a , J. Goubau e , J. De Mey a a
Department of Radiology, Universitair Ziekenhuis Brussel, Brussels, Belgium Department of Experimental Anatomy, Vrije Universiteit Brussel, Belgium Department of Foot and Hand Surgery, Centre Hospitalier Régional de Wallonie Picarde, Tournai, Belgium d Department of Hand Surgery, Europa Ziekenhuizen, Brussels, Belgium e Department of Orthopaedic Surgery, UZ Brussel, Brussels, Belgium b c
a r t i c l e
i n f o
Article history: Received 21 April 2010 Received in revised form 25 May 2010 Accepted 28 May 2010 Keywords: MRI extrinsic ligaments Carpal instability Wrist Injuries and wrist
a b s t r a c t Eighty-nine MR examinations of the wrist were retrospectively analyzed. MRI results were compared with clinical findings and/or arthroscopy. Thin proton density and T2 weighted sequences and 3D DESS weighted sequences were applied on a 1.5 T scanner. On the palmar side three radiocarpal ligaments are recognized including the radioscaphocapitate, radiolunotriquetral, radioscapholunate, and midcarpal triquetroscaphoidal ligaments. Ulnocarpal ligaments include the ulnolunate ligament and the ulnotriquetral ligament. On the dorsal side three ligaments are recognized: the dorsal radiolunotriquetral, and the midcarpal triquetroscaphoidal and triquetro-trapezoido-trapezial. The collateral ligaments include the radial and ulnar collateral ligament. MR is a valuable technique in the assessment of the extrinsic and midcarpal ligaments. Depiction of the extrinsic ligaments can best be accomplished with coronal 3D DESS sequences and sagittal and transverse proton density and T2 weighted sequences with thin slices. © 2010 Elsevier Ireland Ltd. All rights reserved.
1. Introduction The extrinsic ligaments likely are as important as the intrinsic ligaments in the setting of carpal instability. Early detection of injuries is necessary for adequate treatment. Lesions of the carpal ligaments often lead either to functional impairment of the wrist (dynamic instability) or to malalignment of the carpal bones (static instability). Initial symptoms are wrist discomfort, grip weakness and click phenomena, which later will progress to limited range of motion and finally to osteoarthritis of the wrist [1–5]. The dorsal radio(luno)triquetral and palmar scapho-trapezoidotrapezial ligaments are secondary stabilizers and when injured are responsible for stage III scapholunate dissociation. Lesions of the palmar arcuate ligament (triquetroscaphoidal ligament) and the dorsal intercarpal ligament (triquetroscaphoidal and triquetrotrapezoido-trapezial ligaments) are responsible for midcarpal
∗ Corresponding author. Department of Radiology, UZ Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium. E-mail addresses: [email protected] (M. Shahabpour), [email protected] (M. De Maeseneer). 0720-048X/$ – see front matter © 2010 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejrad.2010.05.043
instability. MRI and arthroscopy are both imaging methods that allow a direct visualization and analysis of the wrist ligaments. Presently, arthroscopy of the radiocarpal and midcarpal joint is the gold standard in the diagnosis of carpal instability. Wrist arthroscopy however is an invasive technique and is limited by the fact that the dorsal ligaments cannot be visualized due to the dorsal approaches of current wrist arthroscopy. The technique is performed in patients who present with functional discomfort and non-specific radiological and clinical findings, but also when these findings indicate the need for surgery [6,7]. MRI is limited by the oblique or double-oblique course in 3D space of the extrinsic ligaments and image interpretation needs to be based on the sum of adjacent thin MR slices. In our practice, we are able to analyze the ligaments based on images obtained in the three orthogonal planes. The main objective of the examination of the ligaments is to recognize injuries with an unfavourable prognosis that require a specific treatment. A few correlative studies between MRI and arthroscopy (usually with a limited number of patients) have been published about the intrinsic ligaments (especially the scapholunate ligament) [8]. A very limited amount of studies focus on the extrinsic ligaments. The purpose of this work is to describe the normal anatomy of the extrinsic ligaments, based on correlations with arthroscopy and clinical findings.
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Table 1 Overview of extrinsic and midcarpal ligaments. Palmar Radiocarpal Radioscaphocapitate Palmar radiolunotriquetral (radiolunate/palmar lunotriquetral) Radioscapholunate Midcarpal Palmar triquetroscaphoidal (arcuate) Scaphotrapeziotrapezoidal Ulnocarpal Ulnotriquetral Ulnolunate Dorsal Radiocarpal Dorsal radio(luno)triquetral Midcarpal Dorsal intercarpal (dorsal triquetroscaphoidal and triquetrotrapezoidotrapezial)
2. Materials and methods Our work is based on the retrospective analysis of eighty-nine MR examinations of the wrist. In some cases, an MR examination of the contralateral asymptomatic wrist was also obtained. These patients presented with chronic middorsal or midpalmar pain. MRI findings were correlated with clinical outcome or with arthroscopy [7]. A 1.5 T Symphony Vision (Siemens, Erlangen, Germany) was used. Proton density and T2 weighted sequences were performed with the following imaging parameters: TR/TE, 4000/13, 4000/77; slice thickness, 2 mm; slice interval, 0.2 mm; number of acquisitions, 1; FOV, 100 × 100; matrix size, 256 × 256. 3D DESS (dual echo with steady-state precession) sequences were obtained with the following parameters: TR/TE, 23/9; flip angle, 25◦ ; slice thickness, 1 mm; number of acquisitions, 1; FOV, 100 × 100; matrix size, 256 × 256. Cadaveric images were studied for anatomical correlation. 2.1. Pictorial essay In this work we describe the normal MR appearance of radiocarpal and ulnocarpal extrinsic ligaments. Our work is based on anatomic descriptions in the medical literature, cadaveric studies, MR imaging, and arthroscopic and clinical correlation. An overview of the ligaments is given in Table 1. The extrinsic ligaments join the distal end of radius or ulna to carpal bones (while the intrinsic ligaments arise and insert on carpal bones). The anatomy of the extrinsic ligaments is complex. They are intracapsular and encompass radiocarpal ligaments (between the radius and the carpal bones) and ulnocarpal ligaments (between the ulna and the carpal bones). All the radiocarpal ligaments are proximally attached to the distal part of the radius and insert distally on one or more carpal bones. They represent areas of capsular thickening. Their orientation is usually oblique and hence several adjacent thin slices are necessary to analyse the entirety of the ligaments. The ligaments present a fasciculated and striated morphology with alternating bands of hypointense and hyperintense signal intensity [9–11]. Several extrinsic ligaments are described at the level of the palmar and dorsal parts of the carpus. Palmar ligaments are thicker and stronger than dorsal ligaments. They are important stabilizers of wrist movements [12–15]. Although there are several variations of the description of the ligaments, we recognize two groups on the palmar side (with a V-
Fig. 1. Cadaveric dissection (courtesy of David Connell, London, UK). Note the radiolunate (RL), palmar lunotriquetral (LT), and radioscaphocapitate (RSC) ligaments. Normal interruption of fibers is seen at the lunate attachment of RL and LT ligaments (arrow).
shape), and a group with a transverse orientation (with a reversed V-shape) on the dorsal side. 2.1.1. Palmar radiocarpal ligaments On the palmar side, three strong extrinsic radiocarpal ligaments are clearly identified: the radioscaphocapitate, long radiolunate, and radioscapholunate ligaments (Figs. 1–5). The radioscaphocapitate ligament (RSC) originates from the styloid process of the radius (Figs. 1–5). It overlies the waist of the scaphoid (maintaining the position of the scaphoid as it acts like a seat belt). It inserts on the palmar side of the capitate. It acts like a spindle around which the scaphoid revolves and is fundamental for scaphoid stability [16–20].
Fig. 2. 3DESS sequence with 1 mm thick slice. Note radiolunate (RL), palmar lunotriquetral (LT), and radioscaphocapitate (RSC) ligaments. L, lunate; R, radius.
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Fig. 3. Drawing. Illustration shows radioscaphocapitate (RSC), radiolunate (RL), and palmar lunotriquetral (LT) ligaments. Also note radioscapholunate ligament (RSL) and the inconstant short radiolunate (RLC).
Fig. 5. T2 weighted MR image with 2 mm thick slice. Normal radioscaphocapitate ligament (arrow).
Fig. 4. Arthroscopic view. Note radiolunate (RL) and radioscaphocapitate (RSC) ligaments. Interligamentous sulcus is seen between the two ligaments (arrow).
The palmar radiolunotriquetral ligament (RLT) or long radiolunate ligament courses parallel to the radioscaphocapitate ligament (Figs. 1–4). It originates from the palmar margin and from the styloid process of the radius and courses to the radial margin of the palmar surface of the lunate. It then courses obliquely to the palmar side of the triquetrum. It is covered by the ulnotriquetral ligament at this site. The fibers of the RLT may be interrupted at the lunate attachment and hence two distinct ligaments are present: the long radiolunate and the palmar lunotriquetral. The RLT ligament is the longest ligament of the wrist [21–24]. The radioscapholunate ligament (or ligament of Testut) originates between the long and the short portions of the radiolunate ligament (Figs. 3 and 6). Its fibers are embedded in the interosseous scapholunate ligament. It is located deeper than the RSC and RLT ligaments. It rather represents a synovial fold which retains a neurovascular bundle. At arthroscopy it serves as a reference to point
Fig. 6. Proton density weighted MR image with 2 mm thick slice. Normal radioscapholunate ligament (RSC) (arrow).
out the scapholunate ligament [25,26]. These three palmar ligaments can be visualized at arthroscopy. At arthroscopy only the short intra-articular part is visible. The short radiolunate ligament, which is not described by all the researchers, is close to the palmar fibers of the triangular fibrocartilaginous complex (Fig. 3). It is a palmar capsular thickening. Its origin is on the palmar and ulnar rim of the distal part of the radius and the ligament inserts on the proximal part of the palmar surface of the lunate. This ligament stabilizes the lunate [27]. The midcarpal triquetro(capito)scaphoidal ligament (arcuate ligament) has an oblique course deep in the carpal tunnel and is
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Fig. 7. Transverse proton density weighted image. The arcuate (palmar triquetroscaphoidal) ligament is seen deep in the carpal tunnel (arrows).
Fig. 9. Proton density weighted image with 2 mm thick slice. Note ulnolunate ligament (arrow).
Fig. 10. Proton density weighted image with 2 mm thick slice. Note anterior insertion of ulnotriquetral ligament (arrow). Fig. 8. Drawing. Palmar ulnolunate (UL) and ulnotriquetral (UT) ligaments are attached to triangular fibrocartilage (TFC).
visible on almost all tranverse MR scans of the wrist. It plays an important role in the pathogenesis of midcarpal instability (Fig. 7) [28]. 2.1.2. Ulnocarpal ligaments The proximal palmar ligament group (with a V-shape) is made up of the extrinsic ulnotriquetral and ulnolunate ligaments on the medial side, and of the extrinsic radiolunotriquetral ligament on the lateral side (Fig. 8). This group stabilizes the lunate and hence the proximal row of the carpal bones. The ulnocarpal ligaments originate on the palmar rim of the triangular fibrocartilage and the base of the styloid process of the ulna. The ulnolunate ligament is located adjacent to the short radiolunate ligament (Fig. 9). It follows a similar course, and inserts on the palmar side of the lunate. The ulnotriquetral ligament inserts on the triquetrum [20,29–31] (Figs. 9 and 10). The ulnotriquetral ligament has a dorsal and a palmar bundle. The ligament is located in close
Fig. 11. 3D DESS sequence with 1 mm thick slice. Note anterior insertion of the palmar ulnotriquetral ligament (arrow) on the TFC.
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Fig. 14. Same cadaveric specimen. Note dorsal radiotriquetral (RT), triquetroscahoidal (TS), and triquetrotrapezoidotrapezial ligaments (TT).
Fig. 12. Drawing. Note dorsal radiotriquetral (RT) ligament. Also note two mediocarpal ligaments: the triquetroscaphoidal (TS), and triquetro-trapezoido-trapezial (TT) or dorsal intercarpal ligament. CR, radial collateral ligament; CU, ulnar collateral ligament.
proximity to the meniscus homologue and both may be difficult to differentiate. In our experience the meniscus homologue can only be well visualized with MR arthrography (Fig. 11). 2.1.3. Dorsal radiocarpal ligaments Dorsal ligaments (Fig. 12) are thinner and biomechanically less important than palmar ligaments. The dorsal radiolunotriquetral ligament (Fig. 13) (radiocarpal ligament) is the main extrinsic ligament, originating from the distal radius (at the level of Listers’
tubercle and/or the styloid process of the radius) to the lunate and the triquetrum. Several intrinsic midcarpal dorsal ligaments link the carpal bones. Among these ligaments, the dorsal intercarpal ligament (Figs. 12–14), which includes the triquetroscaphoidal and the triquetro-(trapezoido)-trapezial [27,31–34]. The dorsal ligamentous group which has a transverse orientation (with a reversed V-shape) is composed of these ligaments. They also participate in the stability of the proximal row of the carpus. According to the arthroscopic correlation study performed by Scheck et al in 20 patients who underwent surgery and were examined with MRI or with MR arthrography, radiocarpal ligaments can not be accurately analysed on MRI, even with thin slices [8,35]. According to our experience, ligaments could be depicted on MRI, especially when using intravenous injection of contrast [30–31]. The hyperemia of the surrounding synovia allows a better visualisation of the extrinsic ligaments [36].
Fig. 13. Cadaveric specimens (A and B) 3D DESS sequence with 1 mm thick slice. Note extrinsic radiotriquetral ligament in A (arrow). Note radiotriquetral ligament (RT) and midcarpal triquetroscaphoidal (TS) and triquetrotrapezoidotrapezial ligament (TT) in B.
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2.1.4. Collateral ligaments Collateral ligaments of the wrist correspond to thickened areas of the fibrous capsule. These ligaments can be seen at arthroscopy but may be difficult to visualize on MRI. They do not play an important role in wrist instability, but may be a cause of pain when injured. Their function is less important than those of the knee or elbow. The radial collateral ligament is a dorsal extension of the palmar radioscaphoidal ligament and originates from the apex of the styloid process of the radius to insert itself to the scaphoid waist. The ulnar collateral ligament reinforces the palmar ulnotriquetral ligament and originates proximally from the base and to the body of the styloid process of the ulna (with an extension towards the triangular fibrocartilage of the carpus). It inserts distally to the triquetrum and to the pisiform [29]. In conclusion, in our experience the extrinsic ligaments can be well visualized with the sequences described earlier including coronal 3D DESS, and sagittal and axial proton density and T2 weighted images. 3D DESS sequences with reconstructions in the three orthogonal planes can also be valuable when available on the MR system. It is important to analyze all imaging planes to obtain a complete view of the ligaments given the oblique course of many ligaments. References [1] Linscheid RL, Dobyns JH, Beabout JW, Bryan RS. Traumatic instability of the wrist: diagnosis, classification and pathomechanics. J Bone Joint Surg 1972;54A:1612–32. [2] Trail IA, Stanley JK, Hayton MJ. Twenty questions on carpal instability. J Hand Surg Eur Vol 2007;32:240–55. [3] Schmitt R, Frochner S, Coblenz G, Christopoulos G. Carpal instability. Eur Radiol 2006;16:2161–78. [4] Theumann NH, Etechami G, Duvoisin B, et al. Association between extrinsic and intrinsic carpal ligament injuries at MR arthrography and carpal instability at radiography: initial observations. Radiology 2006;238:950–7. [5] Adler BD, Logan PM, Janzen DL, et al. Extrinsic radiocarpal ligaments: magnetic resonance imaging of normal wrists and scapholunate dissociation. Can Assoc Radiol J 1996;47:417–22. [6] Roulot E. Arthroscopie du poignet. In: Godefroy, et al., editors. Intérêt diagnostique et thérapeutique dans Imagerie du poignet et de la main. Paris: Sauramps Médical; 2001. [7] Dautel G, Et Blum A. In: Godefroy, et al., editors. Place de l’arthroscanner et de l’arthroscopie dans le diagnostic des instabilités du poignet dans Imagerie du poignet et de la main. Paris: Sauramps Médical; 2001. [8] Scheck RJ, Romagnolo A, Hierner R, Pfluger T, Wilhelm K, Hahn K. The carpal ligaments in MR arthrography of the wrist: correlation with standard MRI and wrist arthroscopy. J Magn Reson Imaging 1999;9:468–74. [9] Shahabpour M, Allemon B, Kichouh M, Ceuterick P, De Maeseneer M, De Mey J. MR imaging of volar radiocarpal and ulnocarpal ligamentous lesions using thin slices with clinical and surgical correlation. In: Poster Presented at RSNA. 2008. [10] Totterman SM, Miller R, Wasserman B, Blebea JS, Rubens DJ. Intrinsic and extrinsic carpal ligaments: evaluation by three-dimensional Fourier transform MR imaging. AJR 1993;160:117–23. [11] Brown RR, Fliszar E, Cotten A, Trudell D, Resnick D. Extrinsic and intrinsic ligaments of the wrist: normal and pathologic anatomy at MR arthrography with three-compartments enhancement. Radiographics 1998;18:667–74.
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