The Role of Imaging in Diagnosing Diseases of the Distal Radioulnar Joint, Triangular Fibrocartilage Complex, and Distal Ulna

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1 Musculoskeletal Imaging Review Squires et al. Imaging Joint Abnormalities Musculoskeletal Imaging Review Judy H. Squires 1 Eric England Kaushal Mehta Robert D. Wissman Squires JH, England E, Mehta K, Wissman RD Keywords: arthrography, CT, distal radioulnar joint, MRI, radiography, triangular fibrocartilage complex DOI: /AJR Received July 16, 2013; accepted after revision October 19, All authors: Department of Radiology, University of Cincinnati College of Medicine, 234 Goodman St (Mail code 0761), Cincinnati, OH Address correspondence to J. H. Squires (joodysquires@gmail.com). AJR 2014; 203: X/14/ American Roentgen Ray Society The Role of Imaging in Diagnosing Diseases of the Distal Radioulnar Joint, Triangular Fibrocartilage Complex, and Distal Ulna OBJECTIVE. The purpose of this article is to review the anatomy, biomechanics, and multimodality imaging findings of common and uncommon distal radioulnar joint (DRUJ), triangular fibrocartilage complex, and distal ulna abnormalities. CONCLUSION. The DRUJ is a common site for acute and chronic injuries and is frequently imaged to evaluate chronic wrist pain, forearm dysfunction, and traumatic forearm injury. Given the complex anatomy of the wrist, the radiologist plays a vital role in the diagnosis of wrist pain and dysfunction. T he distal radioulnar joint (DRUJ) plays a key role in forearm stabilization and rotation. It is a site of both acute and chronic injuries and is frequently imaged to evaluate chronic wrist pain, forearm dysfunction, and traumatic forearm injury. The purpose of this article is to review the complex anatomy and biomechanics of the DRUJ, triangular fibrocartilage complex (TFCC), and distal ulna and to review the imaging findings of common clinical conditions. Anatomy and Biomechanics Osseous The DRUJ is a synovial-lined pivot joint formed by the concave surface of the sigmoid notch of the distal radius and the convex surface of the distal ulna, the ulnar seat. During normal forearm pronation and supination the ulna remains fixed allowing the distal radius to rotate, although by convention the position of the distal ulna is described in relation to the radius [1]. The sigmoid notch has a larger arc of curvature than the ulnar seat, which allows a translational movement component that is unique to the DRUJ [1]. During supination, there is volar translation and proximal migration of the ulnar head and conversely, dorsal translation and ulnar lengthening during pronation. Because of the differences in the arc of curvature of the ulnar seat and the sigmoid notch, the bony contact surface of the radius and the ulna differs with fore- arm position, ranging from 60% to 80% in the neutral position to 10% at the extremes of rotation. The variable bony articulation accounts for only 20% of the overall stability of the DRUJ, leaving most of the joint to be stabilized by soft-tissue structures [2]. Soft Tissues The primary stabilizer of the DRUJ is the triangular fibrocartilage complex (TFCC). It lies at the distal aspect of the ulna and consists of the dorsal and volar radioulnar ligaments, ulnocarpal ligaments, triangular fibrocartilage (TFC) disk, meniscal homolog, and tendon sheath of the extensor carpi ulnaris (Fig. 1). There is sometimes confusion between the TFCC versus the TFC; the TFC refers to the TFC disk, whereas the TFCC refers to the entire soft-tissue complex, including the disk [3]. The TFC is the central bowtie-shaped disk that lies on the distal pole of the ulna. The TFC forms the primary soft-tissue barrier separating the carpal joint from the DRUJ. Centrally, the disk is thin and avascular and heals poorly. It becomes thickened and more vascular peripherally, especially at its dorsal and palmar aspects, which contribute to the radioulnar ligaments. The meniscal homolog refers to a soft-tissue structure between the ulnar styloid and triquetrum that joins with extensor carpi ulnaris tendon sheath and joint capsule to form a ligamentous stabilizer [4]. The TFC, meniscal homolog, tendon sheath of the extensor carpi ulnaris, and ulnocar- 146 AJR:203, July 2014

2 Imaging Joint Abnormalities pal ligament have marginal contributions to overall DRUJ stability [5, 6]. The dorsal and volar radioulnar ligaments are the primary stabilizers of the DRUJ. There are deep and superficial components of each radioulnar ligament, all of which arise from the medial border of the distal radius. The deep fibers insert on the base of the ulnar styloid process, the fovea, and have the greatest effect on overall joint stability, whereas the superficial fibers insert on the tip of the ulnar styloid [6]. The volar deep fibers prevent volar translation of the radius during pronation, whereas the dorsal deep fibers prevent dorsal translation of the radius during supination [7]. The roles of the superficial fibers of the dorsal and volar radioulnar ligaments are reversed compared with the deep fibers, with the dorsal superficial fibers providing radial stability during pronation and the volar superficial fibers providing stability during supination [8]. Imaging of the Distal Radioulnar Joint Radiography, CT, MRI, ultrasound, conventional MRI, and MR arthrography (MRA) all have roles in evaluating the DRUJ. Radiography may be used to detect ulnar variance, fracture, degenerative change, and dislocation; however, CT is the preferred imaging modality for the latter. Although not commonly used, conventional arthrography may show partial (noncommunicating) and full-thickness (communicating) defects of the TFC. Ultrasound is not frequently used to evaluate the DRUJ but has a role in guiding diagnostic and therapeutic intraarticular injections and aspirations [9]. MRI with a dedicated wrist coil and intraarticular contrast administration is the current reference standard for soft-tissue imaging of the DRUJ [10, 11]. Recently, with advances in MRI sequences with high spatial resolution, signal-to-noise ratio, and contrast-to-noise ratio, unenhanced MRI plays an even more important role in assessment of the DRUJ. Proper technique must be used because of the small size of the structures in question. A dedicated wrist coil, thin-section imaging, and small FOV are requirements [11]. If available, a 3D imaging sequence is preferable to acquire thin sections that can be reconstructed in all three planes [12]. A C D Fig year-old girl with normal triangular fibrocartilage complex. A, Coronal T1-weighted fat-suppressed MR arthrography image of volar-most section shows volar radioulnar ligament (thick arrow) and ulnotriquetral ligament (thin arrow). B, Coronal T1-weighted fat-suppressed MR arthrography image of mid-volar section shows normal meniscus homolog (white arrow), prestyloid recess (black arrow), and triangular fibrocartilage (TFC) (arrowhead). C, Coronal T1-weighted fat-suppressed MR arthrography image of mid-dorsal section shows TFC attachment to ulnar styloid tip (thin arrow) and base (thick arrow). D, Coronal T1-weighted fat-suppressed MR arthrography image of dorsal-most section shows dorsal radioulnar ligament (arrow) and extensor carpi ulnaris tendon (arrowhead). B Ulnar Variance Ulnar variance, or radioulnar index, describes the relative lengths of the carpal articular surfaces of the radius and ulna and Fig year-old boy with ulnar impaction syndrome. Coronal T1-weighted MR image shows ulnar-positive variance with low T1 signal intensity in ulnar aspect of triquetrum (arrow). Fig year-old woman with ulnar impingement syndrome. Frontal radiograph shows ulnar-negative variance with sclerosis and scalloping of ulnar cortex of distal radius at pseudarthrosis with ulna. AJR:203, July

3 is best assessed on standard posteroanterior wrist radiography, which is performed with the wrist in the neutral position, the elbow flexed 90, and the shoulder abducted 90. In the normal wrist, 20% of the axial load of the wrist is transmitted through the ulna and the remaining 80% of the load is transmitted through the radiocarpal joint. The distribution of these forces is altered by the relative position of the radial and ulnar heads in relation to the carpal bones [13]. Additionally, the thickness of the TFC changes with ulnar variance, increasing with negative variance and decreasing with positive variance [14]. Ulnar variance is the distance in millimeters perpendicular to a line overlying the medial articular surface of the distal radius extended toward the ulna. Ulnar-positive variance is when the ulnar articular surface is distal to the radial articular surface. Conversely, ulnar-negative variance is when the ulna is proximal to the radial articular surface. Positive Ulnar Variance and Ulnar Impaction Syndrome In the normal wrist, ulnar positive variance is increased by forearm pronation, grip, and ulnar deviation. Ulnar-positive variance may be congenital but may also be seen in individuals with excessive loading of the ulnar carpus, such as gymnasts, or from malunion of a distal radius fracture. Individuals with positive ulnar variance have increased transmission of force through the ulna with axial loading [13]. A 2.5-mm increase in ulnar variance increases the ulnar load to 42%, which can lead to ulnar impaction syndrome [15]. Ulnar impaction syndrome is excess ulnar-sided load bearing resulting in ulnar impaction on the medial carpus. The increased force of transmission combined with repeated osseous impaction over time can cause thinning, degeneration, and tearing of the TFC. Continued impaction results in chondromalacia of the lunate, triquetrum, and ulnar head. Ulnar impaction syndrome presents as eccentric hypointense marrow signal intensity on T1-weighted images and hyperintense signal intensity with subchondral cystic changes on T2-weighted images [13, 16] (Fig. 2). There are a variety of surgical treatments for ulnar impaction syndrome that focus on reducing the load to the ulnar side of the wrist, depending on the cause of the dysfunction. Osteotomy of a malunited distal radial fracture, resection of the distal ulnar diaphysis (Wafer procedure), resection of the entire distal ulna (Darrach procedure), Squires et al. TABLE 1: Lichtman Classification of Kienböck Disease Classification I II IIIA IIIB IV and resection of the ulnar seat are possible surgical techniques, depending on the location and cause of the disease [10]. Negative Ulnar Variance, Ulnar Impingement Syndrome, and Kienböck Disease Negative ulnar variance is usually a congenital variant of normal anatomy. It occurs in up to 23% of healthy individuals but may be the result of premature physeal closure, trauma, or surgery [13, 17]. A negative ulnar variance of only 2.5 mm reduces the ulnar load from 18% to 4%, with the remaining force being placed on the radius [15]. Fig year-old woman with Kienböck disease. Coronal T1- weighted MR image shows low signal intensity in lunate. Findings Radiographically occult or linear fracture Lunate sclerosis Lunate collapse, fragmentation without scaphoid rotation Lunate collapse, fragmentation with fixed palmar scaphoid rotation Significant carpal degenerative changes Ulnar Impingement Syndrome Negative ulnar variance has been associated with ulnar impingement syndrome and Kienböck disease. Premature physeal fusion or surgical excision of the distal ulna can lead to abnormal contact with the radius proximal to the sigmoid notch. Early changes of ulnar impingement syndrome include bone marrow edema, cortical thinning, and remodeling of the radial cortex on MRI. If present for many years, progressive degenerative changes at the pseudarthrosis may result in sclerosis and scalloping of the radius, which are visible on conventional radiographs [10] (Fig. 3). Clinically, patients have wrist pain at the extremes of pronation and supination as well as grip weakness that can be debilitating. Treatment is directed toward reducing the amount of impingement and includes resection of osteophytes, ulnar shortening, or ulnar head prosthesis [13]. Kienböck Disease The association of negative ulnar variance and avascular necrosis of the lunate is well known; however, the exact pathophysiology of lunate avascular necrosis remains unclear. It has been proposed that variations in vascular anatomy in addition to lunate geometry can predispose to the development of Kienböck disease [17]. Although there is a consistent palmar arterial supply to the lunate, there is an inconsistent dorsal supply from the radial artery. Current theories on the development of lunate osteonecrosis suggest that a single arterial supply with limited intraosseous branching patterns may predispose to the development of osteonecrosis [18]. The disease occurs most commonly unilaterally in men years old [17]. Diagnosis and staging of Kienböck disease is made radiographically using the Lichtman classification (Table 1), although Kienböck disease can be detected earlier with MRI (Fig. 4). Distal Radioulnar Joint Subluxation and Dislocation DRUJ instability can be easily overlooked radiographically and clinically; therefore, a heightened awareness of the injury is helpful [19]. By convention, it is described by the relationship of the ulna to the radius. Dorsal dislocations are more common and are the re- 148 AJR:203, July 2014

4 Imaging Joint Abnormalities sults of axial loading of the wrist in extension and extreme pronation. Clinically, the wrist is locked in pronation with the patient unable to supinate. Volar dislocations usually occur with extreme axial loading in supination and the wrist is locked in supination [7]. Initial evaluation begins with wrist posteroanterior and true lateral views of the wrist, which unfortunately may be difficult to accurately obtain in the acutely injured individual. As little as 10 of pronation or supination on the lateral image makes evaluation for DRUJ alignment inaccurate [20]. A C D Fig year-old girl with prior distal radius fracture and concern for distal radioulnar joint (DRUJ) instability. A, Normal lateral radiograph shows both scaphopisocapitate relationship and superimposition of radial styloid, proximal scaphoid, and lunate (asterisk). S = scaphoid, P = pisiform, C = capitate. B, In Mino method, ulnar head is located between lines drawn from dorsal and palmar margins of distal radius on pronated axial CT. C, Arcs formed by articular surfaces of sigmoid notch and ulnar seat are drawn in congruency method in neutral position axial CT. D, The epicenter method begins by determining center of rotation of DRUJ (asterisk), which lies halfway between line (straight dashed line) drawn from ulnar styloid (curved dashed line) and center of ulnar head. Perpendicular line (arrowed line) is then drawn from sigmoid chord (solid line) to center of rotation of DRUJ. On a true lateral image, the palmar cortex of the pisiform should project between the palmar cortexes of the scaphoid tubercle and the capitate. This has been described as the scaphopisocapitate (SPC) relationship [21]. Additionally, the proximal pole of the scaphoid, lunate, and radial styloid should superimpose (Fig. 5). On a normal lateral radiograph, the ulna projects 2-mm dorsal to the radius; a distance of 6 mm or more between the distal radius and ulna on a true lateral radiograph is diagnostic of instability [22]. On a frontal image, there is an increased gap between the distal radius and ulna with dorsal dislocation and superimposition of the radius and ulna with volar dislocation [20] (Fig. 6). CT is the modality of choice for evaluating DRUJ stability. Dynamic imaging can be obtained with the wrist in the neutral position, full supination, and full pronation [20]. There are three methods to evaluate for instability: the Mino method, the congruency method, and the epicenter method. The Mino (or radioulnar line) method begins by drawing a line through both the volar and dorsal margins of the distal radius, which is extended B AJR:203, July

5 Squires et al. through the ulnar head. Instability is present if more than 25% of the head of the ulna lies volar or dorsal to these lines [20]. The congruency method is based on arcs drawn across the articular surfaces of the ulnar seat and the sigmoid notch. If the distance between these arcs varies at any point along the curve, there is instability [10, 23]. The epicenter method begins by determining the center of rotation of the DRUJ, which lies halfway between the ulnar styloid and the center of the ulnar head. A perpendicular line is then drawn from the chord of the sigmoid notch to the center of rotation of the DRUJ (Fig. 5). The DRUJ is considered normal if the line is in the middle half of the sigmoid notch [10, 24]. Sensitivities of these methods range from 55% to 100%, and there are high false-positive rates for the Mino and congruency methods [24, 25]. The epicenter method is the most specific because it compensates for the normal translational movement of the DRUJ and is currently the preferred method for detecting subluxation and dislocation [24]. A Fig year-old man with distal radioulnar joint (DRUJ) dislocation. A C, Lateral (A) and frontal (B) radiographs and volume rendered CT image (C) show type 1 ulnar styloid fracture and volar DRUJ dislocation. Note superimposition of radius and ulna on frontal view. Fracture Dislocations DRUJ derangement often occurs as the result of fracture of the distal radius or ulna. The most common fracture associated with a DRUJ injury is the distal radial fracture [7], up to 19% of which are associated with DRUJ instability [26]. Malunited distal radial fractures can result in DRUJ derangement through creating instability, incongruity, or ulnocarpal impaction [7]. Fractures of the distal radius are also commonly associated with an ulnar styloid fracture [26]. Type 1 ulnar styloid fractures involve the distal tip, whereas type 2 fractures involve the base of the ulnar styloid, the fovea. Type 1 fractures spare the deep dorsal and volar radioulnar ligaments of the TFCC, which attach to the base of the ulnar styloid and are less clinically significant. Type 2 fractures involve the base of the ulnar styloid, resulting in disruption of the TFC attachment and DRUJ instability [27]. In either case, a styloid fragment may induce wrist pain and impinge on the extensor carpi ulnaris tendon sheath, resulting in progressive damage to the TFCC and DRUJ instability [10]. Additionally, if a fracture clinically is irreducible or unstable, open reduction with TFCC examination and possible repair is indicated [26]. The bony fragment should be removed to avoid foreign body irritation and impingement effects [28]. Galeazzi Injury Galeazzi fracture-dislocation is defined as DRUJ instability with a displaced radial fracture at any level, although commonly the fracture involves the distal third of the radius [29]. These injuries account for 3 7% of all forearm fractures and occur as a result of a fall on an outstretched hand [30]. Galeazzi fracture-dislocations often include ulnar styloid fractures and TFC tears and may result in dorsal DRUJ dislocation (Fig. 7). MRI B may be useful for evaluating the surrounding soft tissues. Surgery is essential to correct the underlying DRUJ instability [30]. Essex-Lopresti Injury The Essex-Lopresti injury is a proximal radial head or neck fracture that occurs in conjunction with DRUJ dislocation. This injury is complicated by interosseous membrane rupture with injury to the central ligamentous band of the membrane, the interosseous ligament. This results in longitudinal radioulnar dissociation and proximal migration of the radius in relation to the ulna, which can be over- Fig year-old man with Galeazzi fracture-dislocation. Frontal radiograph shows angulated fracture of distal one third of radius as well as distal radioulnar joint dislocation. C 150 AJR:203, July 2014

6 Imaging Joint Abnormalities looked in the acute setting [31]. Delayed diagnosis may result in irreducible radioulnar dissociation, increased loadbearing on the ulna, and resultant ulnar impaction syndrome [32]. Clinically, there can be severe impairment with decreased forearm rotation and wrist extension as well as decreased ability to perform movements while grasping objects. Fig year-old man with Essex-Lopresti fracture-dislocation. Frontal forearm radiograph shows distal radioulnar joint dislocation and displaced fracture of radial head. This patient has fracture-dislocation of elbow as well. Fig year-old woman with both radial and peripheral tears (arrows) of triangular fibrocartilage on coronal fast spin-echo T2-weighted fatsuppressed MR image. The diagnosis can be made radiographically, although MRI can evaluate the interosseous membrane and ligaments (Fig. 8). Treatment typically involves surgical correction of the proximal radius fracture with prosthesis placement if the radial head cannot be preserved, which sometimes relieves the radioulnar length discrepancy. Temporary fixation of the distal radius and ulna is usually performed to allow healing of the DRUJ [31]. Triangular Fibrocartilage Complex TFCC pathology may result from acute trauma (typically in patients under 40 years old) or progressive arthrosis. Patients present with complaints of ulnar-sided wrist pain that is increased with dorsiflexion of the wrist, axial loading, and ulnar deviation [33]. Posttraumatic localized swelling, pain, grip weakness, crepitus, and unstable feeling of the DRUJ are common [34]. MRI The TFC is the triangular fibrocartilage structure extending from the articular cartilage of the radius to the ulnar styloid and fovea. The dorsal and volar radioulnar ligaments are best visualized on axial images as low-signal-intensity bands that attach to the fovea and styloid tip. On coronal images, these bands may appear striated or there may be focal intermediate signal intensity between the two attachments, known as the ligamentum subcruentum [35]. The radial attachment of the TFC normally appears intermediate in signal intensity compared with the adjacent articular cartilage. These normal findings should not be confused with tears. Degenerative changes in the TFC appear as increased T1 signal intensity and slightly increased T2 signal intensity that may mimic a tear but will not show fluidlike increased T2 signal intensity and will not extend to the articular surface (similar to degeneration of the menisci in the knee) [11]. TFC tears will have linear increased signal intensity (similar to fluid) on T2-weighted images [11, 36] (Fig. 9). Asymptomatic defects, including full-thickness communicating defects between the DRUJ and radiocarpal joint, are common, particularly in individuals over 50 years old [37]. The literature is mixed regarding the sensitivity and specificity of conventional MRI in detecting peripheral TFCC tears, ranging from sensitivity of % [34, 38]. Current data show that TFC tears are best visualized with MRA, in which injected contrast material will traverse the torn structure and the sensitivity of detecting peripheral tears is higher than arthroscopy at 85% [39, 40]. Palmer Classification of TFCC Injury Palmer [41] classified TFCC injury as type 1, acute traumatic, and type 2, chronic degenerative, tears (Table 2). The Palmer class 1A lesion is a tear within the substance of the fibrocartilage disk, with no resultant DRUJ dysfunction, whereas class 1B lesions injure the ligamentous attachment to the ulna. Because the ligaments are intrinsic stabilizers of the DRUJ, these lesions result in significant DRUJ instability. Palmer class 1C lesions require high-energy events, disrupting the distal ulnocarpal ligaments of the TFCC, the ulnolunate, ulnotriquetral, and ulnocapitate ligaments, and are associated with complete radiocarpal dislocation. A class 1D lesion is radial-sided ligamentous disruption of the TFCC, which often occurs with distal radial fractures. Palmer class 2 lesions range from 2A, TFCC wear, to class 2E, involving TFCC perforation with lunate or ulnar chondromalacia, lunotriquetral ligament perforation, and ulnocarpal arthritis [41]. Arthritides Rheumatoid Rheumatoid arthritis (RA) is a systemic autoimmune inflammatory disorder that frequently affects the synovium-lined DRUJ. The DRUJ is involved in 75% of patients TABLE 2: Palmer Classification of Triangular Fibrocartilage (TFC) Complex Lesions Classification Traumatic (1) Degenerative (2) A Central perforation TFC wear B Ulnar avulsion TFC wear and chondromalacia C Distal avulsion TFC perforation and chondromalacia D Radial avulsion TFC perforation, chondromalacia, and lunotriquetral ligament perforation E TFC perforation, chondromalacia, lunotriquetral ligament perforation, and ulnocarpal or radioulnar arthritis or both AJR:203, July

7 Squires et al. Fig year-old woman with rheumatoid arthritis. Axial fast spin-echo T2- weighted MR image shows heterogeneous high T2 signal intensity surrounding and within extensor carpi ulnaris tendon. Oval low-signal-intensity masses (arrows) represent rice-bodies. with chronic rheumatologic disease [42]. RA affects the wrist via three pathologic processes: synovial proliferation, ligamentous laxity, and cartilage degradation with subsequent osseous erosion. The first manifestation is synovial hypertrophy leading to fibrosis, referred to as pannus [43]. Pannus eventually erodes into surrounding structures, including the ligaments. In the DRUJ, progressive synovial infiltration may eventually lead to rupture or dislocation of the supportive ligaments and tendons and resultant DRUJ instability. Gadolinium-enhanced MRI is more reliable for assessing synovitis Fig year-old girl with Madelung deformity. Frontal radiograph shows ulnar tilt of distal radius, triangular shape of carpus, and deformity of distal ulna. and bone erosions and can be used to monitor disease activity. The location of synovitis at times is useful to differentiate RA from other spondyloarthropathies [44, 45]. MRI is well established as an imaging modality in the assessment of wrist damage in RA. Rice-body formation is a nonspecific response to chronic inflammation, manifesting as areas of intermediate signal intensity on T1-weighted images and relatively low signal intensity on T2-weighted images. Their presence on MRI should raise suspicion of an inflammatory arthropathy (Fig. 10). Initial treatment involves antirheumatoid medication. With failed conservative management, potential surgical repairs include tenosynovectomy, synovectomy, DRUJ stabilization, tendon transfer or grafting, or arthroplasty, depending on the clinical scenario [43]. Crystal Deposition Disease Calcium pyrophosphate dihydrate crystal deposition disease may manifest as chondrocalcinosis of hyaline or fibrocartilage, such as in the TFC (Fig. 11). Eventually, structural damage to the joint occurs, with imaging findings typical of pyrophosphate arthropathy. Calcific deposits, joint space narrowing, subchondral sclerosis, cyst formation, and large geodes are evident on radiography. Conservative treatment involves systemic antiinflammatory medications, steroid injection, and splinting. Surgical treatment is indicated after failure of conservative management and is dictated by the location of the disease [46]. Fig year-old man with calcium pyrophosphate dihydrate crystal deposition disease. Frontal radiograph shows irregular linear density in region of triangular fibrocartilage (arrow). Miscellaneous Madelung deformity is the result of a developmental growth disturbance from premature closure of the medial distal radius physis. The diagnosis can be made with radiography when there is medial angulation of the distal radial articular surface, triangular shape of the carpus, and enlargement and deformity of the ulnar head (Fig. 12). On lateral images, there is palmar tilt of the radius, giving the appearance of dorsal ulnar dislocation. MRI may show an abnormally enlarged volar ligament, called Vickers ligament. Treatment is surgical for those with severe deformity and entails release of Vickers ligament and possible osteotomy of the radial metaphysis [47]. Conclusion The complex anatomy of the DRUJ and the unique nature of the joint make diagnosis of wrist pain challenging. This article is an attempt to aid the physician in the radiologic diagnosis of pathologic change to the DRUJ. References 1. af Ekenstam F, Hagert CG. Anatomical studies on the geometry and stability of the distal radio ulnar joint. Scand J Plast Reconstr Surg 1985; 19: Ekenstam F. Osseous anatomy and articular relationships about the distal ulna. Hand Clin 1998; 14: Palmer AK, Werner FW. The triangular fibrocartilage complex of the wrist: anatomy and function. J Hand Surg Am 1981; 6: AJR:203, July 2014

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