ANALYSIS OF CONTACT PRESSURE BETWEEN THE PARTS OF TOTAL HIP JOINT ENDOPROSTHESIS WITH SHAPE DEVIATIONS

2007 ◽  
Vol 40 ◽  
pp. S558 ◽  
Author(s):  
V. Fuis ◽  
T. Návrat ◽  
P. Hlavon ◽  
M. Koukal ◽  
M. Houfek
Author(s):  
Myron Czerniec ◽  
Jarosław Zubrzycki

Total hip arthroplasty is a complex procedure. The achievements of implantology enabled the development of a faithful representation of hip joint physiology as well as the production of materials that can successfully replace damaged natural tissues. A very important issue is the correct selection of the geometry of the endoprosthesis adequate to the load of the joint. Materials used for endoprosthesis are a metal head and a polymer cup (e.g. PE-UHMW). The main interactions in the endoprosthesis are friction and surface pressure, which must be limited, exceeding them causes the destruction of the biomechanical system - plastic deformation of the polymer and the formation of too large and unacceptable radial clearances. Based on the author's developed calculation method of hip joint endoprosthesis contact parameters, the impact on maximum contact pressure and the angle of contact of the joint load was estimated depending on the diameter of the endoprosthesis and radial clearance. The correctness of changing the values of maximum contact pressure from the mentioned parameters was determined. Correspondingly: an increase in joint load causes a linear increase in the maximum contact pressure; increasing the diameter of the endoprosthesis head - their non-linear decrease, and increasing radial clearance - their increase


2014 ◽  
Vol 936 ◽  
pp. 770-775 ◽  
Author(s):  
Vladimír Fuis ◽  
Premysl Janicek

The paper deals with the problems of ceramic head of hip joint endoprosthesis destructions, and with assessing the impact of shape deviations of conical surfaces on the tensile stress under ISO 7206-5 loading. The failure of the hip joint endoprosthesis ceramic head has always traumatic consequences for the patient, since a part of or even the whole endoprosthesis has to be reoperated. Hence, it is desired to reduce the number of implant re-operations to the minimum. Therefore the computational modelling of the stress of the head was realised. The shape deviations of the ideal contact cone areas of the head and stem are parameters that significantly influence the tensile stress in the head and its reliability. The assumed shape deviations of the head’s and stem’s cones are macro shape deviations (different cone taper) and micro shape deviations (unevennes) measured using the IMS-UMPIRE equipment. The stress state in the ceramic heads was solved using the FEM and head’s failure probability is based on the Weibull weakest link theory [4, 5 and 9].


2015 ◽  
Vol 100 ◽  
pp. 530-538 ◽  
Author(s):  
Alexander Polyakov ◽  
Volodymyr Pakhaliuk ◽  
Mykhaylo Kalinin ◽  
Vadym Kramar ◽  
Marina Kolesova ◽  
...  

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