Narrow Results

Background: Restoration of extra-articular and intra-articular parameters are important considerations during operative fixation of distal radius fractures. Restoration of volar tilt by using visual estimation and the ‘lift’ technique has previously been described. The aim of our study was to describe a mathematical technique for accurately restoring the volar tilt of the distal radius to acceptable anatomic values.

Methods: A retrospective review of cases performed using the trigonometry-integrated ‘ lift’ technique (TILT) was performed. This technique uses the pre-operative volar tilt angle as well as the dimensions of the implant to calculate the ‘lift’ required to restore volar tilt. Intra-operative angles were measured using a marked transparency overlay on fluoroscopic images. Pre-operative and post-operative volar tilt were measured and analysed.

Results: Twenty-seven fractures were included in the study, with 20 being classified as Arbeitsgemeinschaft für Osteosynthesefragen (AO) C-type. Pre-‘lift’ volar tilt ranged from 0° to -20°. Post-‘lift’ volar tilt ranged from 2° to 16°, with all but three cases ranging from 5° to 15°. The mean volar tilt achieved was 10.2°.

Conclusions: The trigonometry-integrated ‘lift’ technique resulted in reliable intra-operative restoration of anatomic volar tilt in distal radius fractures.

We offer a short invitation to elementary hyperbolic plane geometry. We first examine the contents of Book I of Euclid's Elements and obtain a hyperbolic plane from the Euclidean one by negating Euclid's parallel postulate and keeping all of his other axioms. Then we explore the fundamentals of hyperbolic plane geometry, and study the structure of its isometries. Finally, we obtain certain identities involving the isometries and evaluate them in the upper half-plane model to derive some trigonometric laws for hyperbolic triangles.