Correction of Biapical Radial Deformities by Use of Bi‐Level Hinged Circular External Fixation and Distraction Osteogenesis in 13 Dogs

Abstract

The forelimbs of dogs with severe biapical radial deformities buckle and have increased radial head rotation and radial torsion. Biapical radial deformities can be managed with proximal and distal radial osteotomies and bilevel hinged circular external fixation.

Correction of antebrachial angulation‐rotation deformities in dogs with oblique plane inclined osteotomies

“…The oblique plane inclined osteotomy also presents several technical challenges, including the need to quantify the rotational component of the deformity . No radiographic methods have been described for such purpose and clinical measurements of radial rotation, as used in 1 dog for which CT was not available, do not correlate with CT measures of radial rotation . CT quantification of radial torsion has been found repeatable, but radial head rotation and carpal rotation are relatively common (Figures and ) and both contribute to radial rotation .…”

“…In addition, deformities can be biapical with components of torsional and varus/valgus malalignment at the level of each deformity . Importantly, the terms rotation and torsion have been used interchangeably in the literature . For the purposes of this study, we use the term radial torsion to signify malangulation of the radius in the transverse plane and use the term rotation to include malalignment of the manus relative to the distal brachium in the transverse plane .…”

Mechanics of Supplemental Drop Wire and Half‐Pin Fixation Elements in Single Ring Circular External Fixator Constructs

“…Further, addition of supplemental fixation elements is mainly relevant to a single ring fixator for stabilizing an isolated bone segment . Stabilization of short juxta‐articular fracture or osteotomy segments may only allow placement of a single ring when applying a circular construct . and most hybrid constructs typically use only a single ring …”

“…Larger diameter half or full splintage pins can also be used as fixation elements on ring components . The combined use of pins and wires as fixation elements securing the same bone segment in a circular or hybrid construct presents some theoretical concerns .…”

“…Pin loosening was a problem noted in an early clinical report where single half‐pins were used to supplement fixation wires in circular fixators in dogs . More recent reports describe effective combined use of fixation wires and half‐pins . A retrospective study evaluating circular constructs to stabilize antebrachial fractures in dogs weighing ≤5 kg found fractures stabilized with a supplemental half‐pin had significantly shorter times to union [mean (SD) of 54 (23) days] and were less likely to have ulnar resorption (1/9 fractures) than fractures in which a supplemental fixation wire was used [mean (SD) of 79 (29) days; 6/11 fractures]…”