Author/Editor		Herman, S; Antolič, V; Iglič, A; Kralj-Iglič, V
Title		Relative abductor strength after varus and valgus osteotomy of the proximal femur
Type		članek
Source		In: Miklavčič D, Bajd T, Stanič U, editors. Proceedings of the 9th international conference on mechanics in medicine and biology; 1996 Jun 30-Jul 4; Ljubljana. Ljubljana: Slovenian society of medical and biological engineering,
Publication year		1996
Volume		str. 18-21
Language		eng
Abstract		Relative abductor strenght (RAS) is defined as the difference between the available (maximum) abductor force and the required abductor force i.e. the force needed to maintain the mechanical equilibrium of the pelvis. In this work the dependence of RAS on the centrum-collum-diaphyseal angle and on the position of the greater trochanter was studied using a 3-D mathematical model of the human hip in the monopodal stance. Simulation of varus and valgus osteotomy was done for the normal, 3 cm distal and 5 cm proximal position of the greater trochanter before the operation. It was shown that after valgisation a significant reduction in RAS is to be expected. On the other hand, varisation osteotomy is not associated with a significant change in RAS. The changes in RAS after valgisation for normal and distal position of the greater trochanter occur within the scope of the negative Trendelenburg sign (RAS>). A negative RAS and, consequently, a positive Trendelenburg's sign occur only in extreme valgisationwith a proximally situated greater trochanter. Reduction in RAS may reduce the capability of the hip muscles during strenuous physical activity and may thus participate to earlier muscle fatigue. The importance of special rehabilitation programme after valgisation osteotomy is stressed.
Descriptors		HIP JOINT OSTEOTOMY MUSCLE CONTRACTION BIOMECHANICS FEMUR MODELS, THEORETICAL