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V Antolic

Publications and source records attributed to V Antolic.

24 records · Page 2Linked to original sources

Determination of the femoral and pelvic geometrical parameters that are important for the hip joint contact stress: differences between female and male.

The difference between male and female femoral and pelvic geometry was studied by considering some geometrical parameters such as interhip distance, inclination of the crista iliaca, diameter of the femoral head and centre-edge angle of Wiberg. The values of these parameters were determined for 79 healthy female and 21 healthy male subjects. Standard anterior-posterior radiographs were used and processed by the computer-aided system. The results show some important sex differences in femoral and pelvic geometrical parameters which determine the hip joint contact stress.

Female↗

Biomechanical study of various greater trochanter positions.

A mathematical model was used in order to evaluate the mechanical situation after lateral, medial, distal and proximal displacements of the greater trochanter. It was calculated that lateral displacement may considerably reduce the hip joint contact force, while medial displacement greatly increases it. The influence of proximalization and distalization is much less pronounced. It was further shown that, regarding the postoperative relative hip abductor muscle strength, lateral and distal displacements of the greater trochanter are favourable, while proximal and medial displacements are not.

Adult↗

The required resultant abductor force and the available resultant abductor force after operative changes in hip geometry.

The required abductor force (Freq) and the available abductor force (Fav) are calculated for different positions of the hip rotation center (RC) and different greater trochanter (GT) shifts in the frontal plane of the body in the one-legged stance. It is biomechanically favorable that Fav exceeds Freq and that the magnitude of the resultant hip joint force (R) after the operation is decreased. The difference between Fav and Freq, which represents the relative abductor strength, increases after medialization of RC and after lateralization of GT. On the contrary, after medialization of GT and after lateralization of RC, the difference decreases, which has unfavorable biomechanical effects. Distalization of GT is favorable because it increases the relative abductor strength.

Biomechanical Phenomena↗

Resultant hip joint force after total hip replacement.

Bending moments acting on the LIMA-LTO femoral stem were calculated using a 3D mathematical model of the hip in the one-legged stance based on muscle anatomical data. The effects of 1 cm medialization and lateralization of the hip joint rotation centre (RC) on the bending moments were determined for different body weights. It was found that the bending moments and hence the stem loosening incidence are higher in lateralization compared to medialization of the RC. In order to diminish the bending moments, body weight should be reduced.

Biomechanical Phenomena↗

Biomechanical analysis of various operative hip joint rotation center shifts.

A mathematical model was used to evaluate the mechanical situation after various operative shifts of the hip joint rotation center. It was concluded that while performing different pelvic osteotomies and the total hip replacement the hip joint rotation center should be shifted as far medially as is technically possible to reduce the magnitude of the hip joint contact force. By contrast, lateralization of the hip joint rotation center strongly increases the magnitude of the hip joint contact force; therefore this should be avoided whenever possible. The superior shift of the hip joint rotation center decreases the strength of the patient's hip abductor muscles and must therefore also be avoided. The inferior shift of the hip joint rotation center is favorable because it increases the strength of the patient's hip abductor muscles.

Adult↗

Computer simulation of periacetabular osteotomy.

A simple static three-dimensional mathematical model of an adult hip in one-legged stance was used to evaluate the mechanical situation after periacetabular osteotomy. We found that the hip joint rotation center shifted as a consequence of the osteotomy. This may have considerable effects on the hip joint resultant force and therefore also on the pressure on the femoral head, which could cause the development of arthrosis.

Acetabulum↗