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. 2016 Apr;8(1):27-33.
doi: 10.1055/s-0036-1581125.

Melone's Concept Revisited: 3D Quantification of Fragment Displacement

Teun Teunis  1 , Niels H Bosma  1 , Bart Lubberts  1 , Dirk P Ter Meulen  1 , David Ring  2
Affiliations

Melone's Concept Revisited: 3D Quantification of Fragment Displacement

Teun Teunis et al. J Hand Microsurg. 2016 Apr.

Abstract

We applied quantitative 3D computed tomography to 50 complete articular AO type C fractures of the distal radius and tested the null hypothesis that fracture fragments can be divided according to Melone's concept (radial styloid and volar and dorsal lunate facet fragments) and that each fragment has similar (1) displacement and (2) articular surface area. Thirty-eight fractures fit the Melone distribution of fragments. Radial styloid fragments were most displaced, and volar lunate fragments were least displaced. Volar lunate fragments had the largest articular surface area. While these findings confirm Melone's concepts, the finding that volar lunate fragments are relatively large and dorsal lunate fragments relatively small suggests that alignment of the volar lunate fragment with the radial styloid may be the key element of treatment and the dorsal lunate fragment may not routinely benefit from specific reduction and fixation.

Keywords: computed tomography; distal radius; fractures; morphology; quantitative.

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Conflict of interest statement

Funding T. T. received research grants from the Prince Bernhard Culture Fund & Kuitse Fund (less than US$10,000) (Amsterdam, the Netherlands), Fundatie van de Vrijvrouwe van Renswoude te's-Gravenhage (less than US$10,000) (The Hague, the Netherlands). D. R. certifies that he, or a member of his immediate family, has or may receive payments or benefits, during the study period from Wright Medical (less than US$10,000) (Memphis, Tennessee, United States), Skeletal Dynamics (less than US$10,000) (Miami, Florida, United States), Biomet (less than US$10,000) (Warsaw, Indiana, United States), AO North America (less than US$10,000) (Paoli, Pennsylvania, United States), and AO International (less than US$10,000) (Dubendorf, Switzerland). All other authors have nothing to disclose.

Figures

Fig. 1
Fig. 1
Unreduced and reduced distal radius fracture model. A fractured radius is shown on the left; the fractured radial diaphysis is already positioned within that of the template (not shown). The fracture fragments are reduced within the unfractured template, shown on the right. The outline of the template's metaphysis is represented by the red dotted line. In the right lower corner, the template's orientation is shown: z-axis represents proximal–distal displacement (loss of height), the x-axis radial–ulnar displacement, and the y-axis volar–dorsal displacement. Overall, multidirectional (3D) displacement is the vector of those axes.
Fig. 2
Fig. 2
Outlined area of gap deformity. The top view of the distal radius articular surface is shown. The red line indicates potential measured absolute gap on sagittal CT view, actually representing the split between the lunate facets and radial styloid. This would results in an overestimation of actual gap. Gap surface area is shown in green. RS, radial styloid; VL, volar lunate facet.
Fig. 3
Fig. 3
Heat map of the density of all fracture lines. (A) Melone fractures. (B) Other type C fractures. Fracture line density follows light's visible color spectrum: purple indicates a low density (<0.5% of all fracture coordinates) and red a high density (>10% of all fracture coordinates) of fractures. Red lines indicate ligamentous attachments. RS, radial styloid; VM, volar medial.
See this image and copyright information in PMC

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