Does trochanteric step osteotomy provide greater stability than classic slide osteotomy? A preliminary study.

The use of a trochanteric slide osteotomy needs a partial weightbearing period to allow safe healing of the osteotomy. We compared the initial rigidity of fixation of the trochanteric slide osteotomy with that of a newly developed technique, the trochanteric step osteotomy. The slide and step osteotomies were tested on six bilateral pairs of cadaveric femora with cyclic shear load of constant amplitude for 100 cycles in both a superior direction to represent standing and 60 degrees of hip flexion to represent a squat stance. Translational and rotational migration and cyclic amplitude were measured with an optoelectronic camera system. During superior loading, translational migration of the slide osteotomy was greater than for the step osteotomy (slide median, 1.7 mm; step median, 0.3 mm), but rotational migration was not (slide median, 1.9 degrees; step median, 0.2 degrees ). Translational amplitude was greater for the slide osteotomy in the superior direction (median slide, 0.3 mm; median step, 0.16 mm), but not in rotational amplitude. Similar trends in migration and amplitude were observed for the squat loading configuration. The data suggest the trochanteric step osteotomy is a more stable construct than the commonly performed slide osteotomy.