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Biomedical subjects

F Srakar

Publications and source records attributed to F Srakar.

11 recordsLinked to original sources
PubMed2001

Salter osteotomy for treatment of acetabular dysplasia in developmental dysplasia of the hip in patients under 10 years.

Serial radiographs of 44 hips in 39 patients undergoing Salter innominate osteotomy for the treatment of dysplastic acetabulum owing to developmental dysplasia of the hip were reviewed. The hips were also evaluated clinically at the last follow-up examination, 7 years to 13 years postoperatively. At 7 years to 13 years postoperative, excellent or good clinical results were assessed in 43 hips (98%), and excellent or good radiographic results in 32 hips (73%). In patients with a postoperative center edge (CE) angle > 24 degrees, the CE angle remained significantly greater throughout the follow-up period compared with patients with a postoperative CE angle < or = 24 degrees. A positive correlation was found between the degree of operative CE angle correction and radiographic findings 7 years to 13 years postoperatively.

Acetabulum↗
PubMed1997

Increased incidence of arthrosis in women could be related to femoral and pelvic shape.

In this study various femoral and pelvic geometrical parameters important for hip joint contact stress were determined. The parameters were measured from standard anteroposterior radiographs of healthy adult subjects and analysed by using descriptive statistical procedures. Women proved to have a significantly smaller femoral head radius and larger distance between the inner acetabular rims than men, both features which lead to an increase of contact stress in the hip joint articular surface. Since too high, long-lasting contact stress is unfavourable regarding the development of arthrosis, we propose that these differences in the femoral and pelvic geometry could be one of the reasons for the increased incidence of arthrosis in women.

Adult↗
PubMed1996

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↗
PubMed1996

Stress distribution on the hip joint articular surface during gait.

The magnitude and the direction of the resultant hip joint force are different in different body positions during gait. Therefore the stress distribution in the hip joint articular surface also changes. The aim of this work is to study how the stress distribution changes if the magnitude and the direction of the hip joint force is changed during gait. For this purpose a three-dimensional mathematical model is developed. We calculated the values of the peak stress and the location of the pole on the articular surface (where the stress is maximal) in the successive phases of the walking cycle. The values of the peak stress range from 0.8 MPa in the one limb stance phase to 2.6 MPa in the heel strike phase.

Cartilage, Articular↗
PubMed1995

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↗
PubMed1994

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↗
PubMed1994

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↗
PubMed1993

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↗
PubMed1992

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↗
PubMedDate not supplied

Treatment of resistant idiopathic pes equinovarus: ten-year experience.

Fifty cases of clubfeet (38 children) were evaluated 10 years after surgery. Turco's method was used in 22 cases, while 24 were managed with Achilles tendon lengthening and dorsal capsulotomy. After Turco's operation, good results were achieved in 69% and the deformity recurred in 31%. In the second group, the success rate was 63%. Recurrences are due to insufficient reduction of the talocalcaneonavicular joint. The authors conclude that Achilles tendon lengthening and posterior capsulotomy should be carried out by age 4 months. If by the age of 1 year the foot has not yet assumed its normal position, complete operative reduction is recommended. Preliminary results of histochemical studies of the peroneal muscles are presented.

Arthroplasty↗