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Comparison of hip joint offset in resurfacing arthroplasty and standard total hip arthroplasty
ČERNÁ, Helena
Comparison of hip joint offset in resurfacing arthroplasty and standard total hip arthroplasty. Summary The subject of this work is to compare a hip joint biomechanical parameters after two different operations, after a standard total hip arthroplasty and after hip surface replacement. Material and method: A group of twenty five patients with a hip surface replacement has been processed in a statistical way, their average age was 55 years (from 34 to 66 years), next a group of thirty patients with a standard total hip arthroplasty and the average age was 62 years in this group (from 46 to 72 years). Anteroposterior radiographs of the pelvis with inside rotation about 15{$\rm^o$} was taken of all patients. The measured biomechanical parameters were femoral offset and femoral length, cup offset and cup height. For statistical processing the total offset was defined as a sum of the femoral offset and cup offset, hip length was defined as femoral length minus cup height. Postoperative measured data of an operated hip joint were compared with preoperative data. Statistical analysis has been done by a paired t-test. Results: The patients, who underwent an operation of hip surface replacement, were in average by 7.8 years younger than the patients with a standard total hip arthroplasty. Men predominated in the group with surface replacement and women predominated in the group with a standard total hip arthroplasty. Preoperative measured data were approximately identical in both groups. In the group with a surface replacement the postoperative total offset has increased in average by 0.04 cm (p=0.79) and hip length has decreased in average by 0.41 cm (p=0.0001). The postoperative total offset has decreased in average by 0.83 cm (p=5x10-5) in the group with a standard total hip arthroplasty and the postoperative hip length has decreased in average by 1.49 cm (p=6.17x10-5). Conclusion: On the basis of taken paired t-tests the hypothesis can be substantiated that a surface replacement restores hip joint physiological conditions better than a standard total hip arthroplasty.
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Napjatostní analýza kyčelního kloubu s povrchovou náhradou - simulace chůze
Návrat, Tomáš ; Florian, Z. ; Fuis, Vladimír ; Štekl, M.
In the works dealing with computational hip join modelling, published on this subject in the past, the hip's loading is modelled so as to correspond to standing on one lower limb. At this standing, man remains symmetric at the considered level of resolution, and the force of gravity is identical with the body's axis. We consider the standing because man at walking always stands on one lower limb, and we suppose that, at this standing, in the hip joint there develops a maximum force (we do not suppose rapid walking or shock load). Since the computational models presented up to now consider the standing on one lower limb, it was decided to test computational modelling of even the step' next phase. The problem was formulated as follows: to make a strain-stress analysis of the hip joint with applied surface prosthesis for various phases of the step.
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