E. Heijens et al., Definition, quantification, and correction of translation deformities using long leg, frontal plane radiography, J PED ORT B, 8(4), 1999, pp. 285-291
The surgical realignment of mechanical axis deviation is necessary to preve
nt early joint degeneration. Modern types of external fixation systems allo
w alignment of the mechanical axis to exact degrees. Predominately, these a
re corrections of angulation deformities. In some cases, the analysis of th
e mechanical axis deviation does not show any angulation deformity, but rat
her a parallel staggering of the mechanical axis lines of a bone. Such para
llel staggering of the mechanical axis lines is defined as a translation de
formity of the bone. In combined deformities with angulation and translatio
n, the center of deformity can be established proximal or distal to the lim
it of the bone. In translation deformities, the realignment of the mechanic
al axis requires a parallel restaggering made by a translation-osteotomy or
by a counterangulated double osteotomy. In complex deformities with angula
tion and translation, the translation requires separate corrective planning
. In frontal plane radiographs of the standing leg, the components of an an
gulation and translation can be established graphically or by simple trigon
ometric formulas. The analysis and surgical procedure to realign translatio
n deformities or a combination of translation and angulation deformities us
ing an unilateral fixator device are discussed.