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THE HAND MINERVA ORTOP TRAUMATOL 2011;62:443-57

Distal radius fractures A review and update

IN C ER O V P A Y R M IG E H DI T C ® A

R. TOSTI 1, A. FOROOHAR 2, M. J. PARK 2, D. R. STEINBERG 2, D. J. BOZENTKA 2

Fractures of the distal radius are relatively common. A significant amount of research has been dedicated to furthering our understanding of these injuries. This article reviews, and provides an update, on the contemporary management of distal radius fractures. Key words: Radius fractures - Colles’ fracture Intra-articular fracture.

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ractures of the distal radius are a common injury that has been reported as 16% of all fractures evaluated in the emergency room. Since the median age of the population is aging, the fracture incidence is expected to increase over the next quarter century especially in those older than 65 years.1, 2 The incidence of distal radius fractures has been shown to follow a bimodal distribution; in general, those most affected are in the first and seventh decades of life.3 Furthermore, correlations between race, gender, and geography have also been identified. Fanuele et al. identified Caucasians as having twice the odds Funding.—The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. Corresponding author: A. Foroohar, MD, Department Of Orthopedic Surgery, University of Pennsylvania School of Medicine, 3400 Spruce Street, 2 Silverstein, Philadelphia, PA 19104, USA. E-mail: [email protected]

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1Department

of Orthopaedic Surgery and Sports Medicine Temple University School of Medicine Philadelphia, PA, USA 2Department Of Orthopaedic Surgery University of Pennsylvania School of Medicine Philadelphia, PA, USA

of fracturing the distal radius than do nonwhite individuals, and post-menopausal women were nearly five times more likely than men.4 Distal radius fractures have long been a topic of fascination and investigation. In 1814, Abraham Colles published the first narrative of distal radius fractures in which the injury was described as a dorsally angulated fracture that healed with “perfect freedom of motion… and completely exempt from pain”.5 Since the early 19th century, the collection of knowledge respective to fractures of the distal radius has expanded exponentially. Numerous reports have elucidated a new understanding of anatomy, mechanisms and patterns of injury, stability, imaging modalities, treatments, complications, and outcomes. Thus as the literature continues to revise our understanding of this interesting injury, the current article aims to review the contemporary body of thought regarding fractures of the distal radius.

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Distal radius fractures


er parameter measured in the AP view; it measures as the difference between the ulnar aspect of the radius articular surface and the ulnar head. Approximately 50% of the general population have an ulnar neutral variance where the length of the ulna and radius are equal. While 25% of the general population are ulnar positive with ulna longer than the radius and 25% ulnar negative in which the ulna is shorter than the radius. These radiographic parameters serve as references to assess for anatomic reduction and to predict outcomes and stability following injury.

Figure 1.—Radiographic anatomy. A) PA view showing ulnar variance, radial inclination, and radial height. Ulnar variance is the difference between the distal articular surface of the ulnar head and the medial corner of the radius. Radial inclination is measured as the angle between the perpendicular line of the radial axis and a line drawn from the radial styloid to the medial corner of the radius. Radial height is the difference between the distal articular surface of the ulnar head to the tip of the radial styloid; B) lateral view demonstrating volar tilt measured as the angle between the perpendicular line of the radial axis and a line drawn from the dorsal to volar rims.

Anatomy

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The distal radius is the major weight bearing structure at the wrist through which forces are transmitted via the carpus. The radius is estimated to bear 80% of the joint reactive force at the wrist, and this load is divided 60% and 40% between the lunate and scaphoid facets respectively.6 The scaphoid and lunate bones articulate with the radius in their respective facets, which are separated by a sagittal ridge. The distal radioulnar joint (DRUJ) is an articulation perpendicular to the radiocarpal joint. The sigmoid notch of the radius is surfaced with hyaline cartilage and seats the distal ulna, and through this articulation, the radius pivots around the ulna to permit pronation and supination. Radiographic benchmarks further characterize the three-dimensional anatomy of the distal radius. In the anterior-posterior (AP) view, radial height and inclination are measured at an average of 11 mm and 23° respectively (Figure 1A). In the lateral view, the articular surface is tilted volarly 12° (Figure 1B). Ulnar variance is anoth-

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Presentation and initial management

The classic presentation of a distal radial fracture is a fall onto an outstretched hand. Other common mechanisms may include motor vehicle collisions, falls from height, or direct trauma to the wrist. Generally, patients present with a deformity at the wrist resulting from shortening and volar or dorsal displacement. Evaluation of high-energy injuries should always being with a proper Advance Trauma Life Support (ATLS) survey. A focused examination of the skin and neurovasculature is also prudent, as open fractures or acute carpal tunnel syndrome are indications for more urgent surgery.7 Although uncommon, evaluation of the neurologic status may reveal deficits in the median nerve distribution, which can be caused by contusion, stretch injury, or compression neuropathy at the carpal canal. Neurologic deficits that progress especially after reduction should raise suspicion for acute carpal tunnel syndrome. Radiographic and imaging evaluation Imaging should begin with orthogonal roentgenograms in the AP and lateral projections preferably before splinting material is applied. An oblique view of the wrist may reveal intra-articular extension not appreciated on the AP and lateral films;


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1. bending (fails under tension) (Figure 2A); 2. compression (impaction of subchondral and metaphyseal bone) (Figure 2B); 3. shearing (force through the joint surface) (Figure 2C); 4. avulsion (fails via ligamentous attachments to radius and ulna) (Figure 2D); 5. combinations 1-4 (high energy injury) (Figure 2E). Extra-articular fractures do not involve either the radiocarpal or distal radioulnar joint. Intra-articular fractures involve either or both of the aforementioned joints. Intraarticular fractures of the radiocarpal joint may be sub-divided as two, three, or four part fractures.


similarly a lateral facet view (20° cephalad tilt) may establish the articular involvement of the lunate facet.8 Radiographs of the contralateral wrist provide a reference if needed for pre-surgical planning. Computed tomography (CT) scan may be a useful adjunct in distinguishing articular step off, displacement, and comminution. Preoperative two or three dimensional CT has been shown to change the surgical approach when compared to solely evaluating the plain film x-rays. Magnetic resonance imaging (MRI) is not a common modality employed acutely in distal radius fractures; however, MRI may provide information regarding the integrity of the triangular fibrocartilage complex (TFCC) and the carpal ligaments.

Treatment

Classification

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Numerous eponyms and classification schemes have been developed in the past two centuries.9 Classic names such as the Colles, Smith, Barton, or Chauffeur fractures still persist in the common workplace dialogue; however more contemporary arrangements have supplanted the eponymous descriptions. For example, Frykman conceived a system identifying intra and extra-articular fractures of the radiocarpal joint and distal radioulnar joint with and without ulnar styloid involvement. This classification system stresses the importance of the distal radial ulnar joint. Melone later characterized an intra-articular classification by separating common fragments such as the radial shaft, radial styloid, dorsal lunate facet, and volar lunate facet. The AO (Arbeitsgemeinshaft fur Osteosynthesefragen) system is the most complex, and follows the typical alphanumeric code. In this system, the distal radius is labeled as 23 followed by types A, B, or C corresponding to an extra-articular, partial articular, or complete articular fracture respectively. The Fernandez Classification system, distinguishes classes by pathomechanism, which predicts stability and gives insight to the optimal treatment:

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The goal of treatment is restoration of pre-injury functional status and avoidance of complications. Whether considering open or closed treatment, fracture personality, patient factors, stability, and associated injuries must be considered in order to achieve this goal. Each case should be evaluated individually, as a low demand or severely ill patient may not be treated the same a young laborer with a highenergy fracture. Regardless of the treatment decision, re-establishing pre-injury function demands an awareness of pathomechanics, which were succinctly summarized by Wolfe in the acronym “ARMS;” each of the following represent factors that should be restored and will be discussed separately:10 1. articular congruity; 2. radial alignment and length; 3. motion; 4. stability. Articular congruity Articular congruity refers to the cartilaginous surface step-off that results in the wear of hyaline cartilage leading to post-traumatic arthritis. Knirk and Jupiter showed that


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Figure 2.—Radiographs depicting examples of the Fernandez classification. A) Type 1 ‑ bending fracture; B) type 2 ‑ shear fracture; C) type 3 ‑ compression fracture; D) type 4 ‑ avulsion or fracture dislocation; E) type 5 ‑ combination or high-energy fracture.

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2 mm of step off resulted in radiographic degenerative changes in 100% of patients (N.=43) at 7 years.11 Radial alignment and length

Proper volar tilt, carpal alignment, radial length, and ulnar variance restores the kinematics of the carpus and radioulnar joint. Regarding volar tilt, McQueen et al. found that functional disabilities began to appear when the loss of volar tilt exceeded 12 degrees, while Porter and associates reported a threshold of 20 degrees.12, 13 McQueen further described that carpal alignment was likely responsible for the functional deficit

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observed in dorsal tilt. In this situation, the lunate will tilt dorsally with the radius, and the midcarpal joint will compensate by flexing, which places tension on the midcarpal joint and may reduce grip strength and forearm rotation.14 Radial metaphyseal failure results in a reduction in radial height and a positive ulnar variance. As this occurs, the ulna begins to bear increasing loads across the wrist, which may impact the carpus, reduce strength, and generate pain.15 Diminished radial inclination has not been as strongly correlated with post injury function as volar tilt or radial height; however a loss


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of inclination increases loads transmitted across the TFCC leading to degenerative changes.16 Motion

Stability

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Volar tilt