Assessing distal radius malrotation following fracture using computed tomography

Abstract

Hypothesis: When the distal fracture fragment in distal radius fractures displaces, it commonly rotates as well as shortens and angulates. Aim: The aim of this study was to assess the frequency and magnitude of malrotation of the distal fracture fragment using computed tomography (CT). Methods: A retrospective radiological assessment of 85 CT scans of the distal radius, 35 following fracture and 50 normal radii, was carried out. We developed and applied a simple method for measuring rotation of the distal radius relative to the diaphysis using routine CT scans of the wrist. A Mann-Whitney analysis was used to identify differences in radial rotation between fractures and controls. Intra-and inter-observer reliability were analyzed using intra-class correlation coefficients (ICCs) and Bland-Altman plots. Results: The articular surface of the distal radius is normally rotated in the long axis of the forearm relative to the diaphysis, either into pronation or into supination. The median radial rotation angle of controls was 1 pronation (range À15 to 4 ) compared to 3 pronation (range À24 to 31 ) in the fracture group. The absolute rotation angle was significantly greater in the fracture group (median 10 , range 0-31 vs. 3 , range 0-15 ; p < 0.001) and outside the "normal range" of controls in 26 cases indicating that 75% had rotated appreciably following injury. Intra-and inter-observer reliability of measurements were good with ICCs of 0.99 and 0.98, respectively. Conclusions: Malrotation of the distal radius appears common following distal radius fracture. Malrotation of the distal fracture fragment has been shown to affect distal radio-ulnar joint function. Despite this, rotational deformity is rarely addressed in clinical practice as it is difficult to appreciate on simple radiographs. The simplified method described here is easy to use in routine clinical practice and also appears reliable. Measuring radial rotation may be an important consideration when planning both primary treatment and corrective osteotomy for patients with distal radial malunion.

A radiographic study of dorsovolar wrist axes and a database of angular measurements on axial computed tomography images

“…The principal axes of the wrist on axial CT sections are used as a reference in studies for following conditions: the distal radius anatomy, [1,4,8,15] rotational malalignment due to distal radius or shaft fractures, [7,9,16] anatomic and kinematic studies of the carpal region, [5,6,10] and DRUJ anatomy. [5,11,12,[17][18][19] Several anatomical locations have been used as principal axis of the distal radius in the past, including, the central axis, [4,[7][8][9]11,12,16] volar cortical axis at metaphyseal level, [5,8,9] and sigmoid notch axis. [5] In the current study, a series of angular measurements based on axial CT images provided improved data for evaluating radiographic anatomy of the wrist.…”

“…The principal axes of the wrist on axial CT sections are used as a reference in the anatomical, kinematic, and clinical studies in patients with different conditions such as distal radius malunion, distal radioulnar joint (DRUJ) instability, and scapholunate ligament injury. [1,[4][5][6][7] However, available data are problematic due to the different landmarks and principal axes preferred for reference. Several different anatomical locations have been used as a principal axis of the distal radius in the past; the central (mediolateral radiocarpal joint) axis, volar cortical axis (at distal metaphyseal level), and sigmoid notch axis.…”

The distal radioulnar joint after distal radial fractures: when and how do we need to treat pain, stiffness or instability?

“…If not and there is pain particularly at extremes of rotation, then it is worth giving a steroid injection in and around the DRUJ. If stiffness persists, I would recommend a CT scan to look for DRUJ congruency; it may also show some unappreciated axial rotation of the distal radius (Filer et al., 2019) (Figure 8). (The importance of this is unclear but appears to have some effect on forearm rotation.)…”

Computer-Assisted 3-Dimensional-Planned Corrective Osteotomy for Symptomatic Fracture Malunion: An Ulna-Only Case Study

“…6 A, B), or an apparent rotation of 4.5° pronation when seen clinically. The absolute rotational deformity angle was measured by subtracting the distal-most axial angle comprising the deformity and the proximal-most axial angle comprising the deformity, as inspired by Filer et al, 10 who used a 5° cut off in either direction as the normal for absolute rotational angles of the distal radius. In our case, we measured the distal angle from the horizon to a line drawn between the ulnar styloid process and a point directly opposite it on the ulnar head/articulating surface to the radius.…”