The Effect of Stem Structure on Stress Distribution of a Custom-Made Hip Prosthesis

2010 ◽  
Vol 224 (11) ◽  
pp. 1275-1284 ◽  
Author(s):  
X Li ◽  
D Li ◽  
Q Lian ◽  
H Guo ◽  
Z Jin
Keyword(s):  
Stress Distribution ◽  
Hip Prosthesis ◽  
Custom Made ◽  
Stem Structure

scholarly journals Hand-Modelled Composite Prostheses after Resection of Peri-Acetabular Bone Malignancies

Sarcoma ◽  
2003 ◽  
Vol 7 (1) ◽  
pp. 19-27
Author(s):  
G. Delepine ◽  
F. Delepine ◽  
T. Sokolov ◽  
N. Delepine
Keyword(s):  
Hip Prosthesis ◽  
Staging System ◽  
Deep Infection ◽  
Extensive Resection ◽  
Reconstructive Procedures ◽  
Acetabular Bone ◽  
Titanium Screws ◽  
Custom Made ◽  
Custom Made Prostheses

Purpose: To improve function after pelvic resection involving the acetabulum, using an anatomic composite implant built with screws and cement.Material and method: Since 1990, 66 patients with peri-acetabular bone malignancies have been treated by extensive resection followed by hand-modelled innominate prosthesis with partially constrained total hip prosthesis. The hand-modelled innominate prosthesis was made of a titanium cup, a set of long titanium screws and two or three packs of gentamycine-loaded cement.Results: Many postoperative complications were observed: deep infection (14%), hip prosthesis dislocation (25%) and local recurrence (15%). Sixteen patients (25%) had to be reoperated. Nevertheless, at last follow-up, 62 patients still had composite prosthesis. The mean functional result, rated according to a modified Enneking's staging system, was 80% with unlimited walking without support, average hip flexion 100°, length discrepancy less than 1 cm.Discussion: These results were similar to those described in the literature for custom-made innominate prostheses and much better than those of alternative reconstructive procedures. Hand-modelled composite prostheses are cheaper, easier, more adaptable and enables better anchorage than custom-made prostheses. Such a procedure can be used even after total iliac wing resection.Conclusion: The advantages of such a procedure plead for its extensive use after acetabular resection. But long-term follow-up is necessary to validate indications.

scholarly journals Assessment of the contact stress distribution dependent on functional and design parameters after total hip arthroplasty

2009 ◽  
pp. 43-53
Author(s):  
Emmanuel Rixrath ◽  
Sylvie Wendling-Mansuy ◽  
Patrick Chabrand
Keyword(s):  
Stress Distribution ◽  
Contact Stress ◽  
Hip Prosthesis ◽  
Distribution Model ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Hip Prostheses ◽  
Total Hip ◽  
Dynamic Loading Conditions ◽  
Contact Stress Distribution

A numerical model was developed to assess the contact stress distribution in total hip prosthesis as a function of geometrical parameters such as the clearance between the bearing surfaces, the inclination and thickness of the UHMWPE cup. The contact stress distribution model proposed is submitted to static loading considering the maximal force during gait and jogging. The results shows that the magnitude of the maximal contact stress remains constant for inclination values in the range of [0-35°] and increase significantly with the cup clearance and liner thickness for inclination values in the range of [35°-65°]. This model could be improved by considering other factors such as friction and dynamic loading conditions. This approach would permit to bring new perspectives for studying the long-term behaviour of total hip prostheses.

scholarly journals Machinability evaluation of titanium alloy Ti-6Al-4V obtained by EBM for functional part at medical application

2021 ◽  
Author(s):  
António Festas ◽  
A. Ramos ◽  
J. P. Davim
Keyword(s):  
Titanium Alloy ◽  
Medical Devices ◽  
Surface Finish ◽  
Feed Rate ◽  
Cutting Forces ◽  
Hip Prosthesis ◽  
Cutting Speed ◽  
Test Sample ◽  
Turning Operations ◽  
Custom Made

Abstract The potential and advantages revealed by the application of 3D manufacturing techniques such as Electron Beam Melting (EBM) in the production of medical devices such as orthopaedic implants are increasing manly in custom made devices. However, the use of milling and turning operations are indispensable on surfaces where surface finish and dimensional accuracy have more demanding requirements. This work aims to evaluate the machinability of titanium alloy test samples submitted to turning operations, to obtain the geometry of a functional cone of the modular component of the hip prosthesis. The differences in cutting forces and surface finish obtained in the turning tests are compared between a wrought Ti-6Al-4V test sample and three obtained by EBM with different thicknesses. To perform the tests, a constant cutting speed of 60m/min was used, feed of 0.1 and 0.2mm/rev and ap of 0.15mm. The cutting forces were measured for each test, also the roughness was measured in the form of Ra, Rt and RzD in each test sample. From the results obtained, EBM test samples presented higher roughness values and lower resulting cutting forces. In both materials, the effect of feed rate is visible. When machining a cone, the passive force and the cutting force become the most influential forces. Generally, when the feed rate value was doubled, the resulting machining forces value increased up to about 50% for both types of materials and the Ra value to approximately 200%. The EBM technology as used form medical devices allow good quality surfaces as the wrought titanium alloy.

HIDE: a new hybrid environment for the design of custom-made hip prosthesis

2001 ◽  
Vol 64 (2) ◽  
pp. 137-144 ◽  
Author(s):  
Marco Viceconti ◽  
Debora Testi ◽  
Roberto Gori ◽  
Cinzia Zannoni ◽  
Angelo Cappello ◽  
...  
Keyword(s):  
Hip Prosthesis ◽  
Custom Made

Numerical Analysis of Femoral Neck Angle Influence on Stress Distribution of Cemented Austin Moore Hip Prosthesis

2012 ◽  
Vol 525-526 ◽  
pp. 41-44
Author(s):  
Lucian Bogdan ◽  
Cristian Sorin Nes ◽  
Nicolae Faur ◽  
Mihaela Amarandei ◽  
Angelica Enkelhardt
Keyword(s):  
Numerical Analysis ◽  
Stress Distribution ◽  
Femoral Neck ◽  
Hip Prosthesis ◽  
Laser Scanner ◽  
Element Analysis ◽  
Abaqus Code ◽  
Femoral Neck Angle ◽  
D Model ◽  
Austin Moore

This paper presents a finite element analysis regarding the stress distribution in a cemented Austin Moore type hip prosthesis. The 3-D model was obtained using a Roland PICZA 3-D laser scanner. The applied loads simulate the normal gait cycle. The prosthesis is made from stainless steel with a femoral head of 45mm diameter. The numerical analysis was performed using the ABAQUS code. The results showed that the stress level in the cement is sensitive to the femoral neck angle. Starting with a standard, 125° angle, and increasing the angle with up to 5°, the resulting stress can be reduced with more than 10%. The proposed angle increase produces a more uniform stress distribution in the cemented section, increasing the durability of the arthoplasty.

scholarly journals Combined and hybrid marker models for radiostereometry assessment of polyethylene liner motion in dual mobility hip prosthesis: a proof-of-concept study

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Peter Bo Jørgensen ◽  
Bart L. Kaptein ◽  
Kjeld Søballe ◽  
Stig S. Jakobsen ◽  
Maiken Stilling
Keyword(s):  
Hybrid Model ◽  
Hip Prosthesis ◽  
Polyethylene Liner ◽  
Computer Assisted ◽  
Proof Of Concept ◽  
Dual Mobility ◽  
Link Type ◽  
Drill Guide ◽  
Custom Made

Abstract Background Investigation of polyethylene liner movement in total hip arthroplasty requires bead-marking for radiographic visibility of the liner. However, occlusion of markers poses a challenge for marker registration in radiographs. Methods The polyethylene of a dual mobility acetabular system was marked with twelve 1-mm tantalum markers (four groups of three markers) using a custom-made drill guide. Liner motion in a phantom and a patient was investigated with dynamic radiostereometry analysis (dRSA) at 1-year follow-up and static radiostereometry analysis (sRSA) postoperatively and at 1- and 2-year follow-up. A combined marker configuration (CMC) model was calculated from the registered positions of the liner markers and the femoral head in several images. Furthermore, the CMC model and the theoretic marker positions from computer-assisted models of the drill guide were combined in a hybrid model. Results The CMC model included eleven markers in the phantom and nine markers in the patient, which was sufficient for dRSA. Liner movement in the phantom followed liner contact with the femoral neck, while liner movement in the patient was independent. The hybrid model was necessary to determine liner orientation in sRSA recordings, which clearly changed from postoperative to 1- and 2-year follow-up even though the patient was positioned similarly. Conclusion Polyethylene liner motion in dual mobility hip prosthesis can be assessed with CMC models in dRSA recordings. In sRSA, the liner position between follow-ups is unpredictable and analysis requires inclusion of all markers in the model, accomplished with a hybrid marker model. Trial registration ClinicalTrials.gov [NCT02301182], 25 October 2015.

scholarly journals Revision hip arthroplasty by Waldemar Link custom-made total hip prosthesis

2010 ◽  
Vol 67 (2) ◽  
pp. 179-182
Author(s):  
Ivica Medenica ◽  
Milan Lukovic ◽  
Dragan Radoicic
Keyword(s):  
Hip Arthroplasty ◽  
Hip Prosthesis ◽  
Bone Defects ◽  
Harris Hip Score ◽  
Bone Stock ◽  
Total Hip Prosthesis ◽  
Pelvic Discontinuity ◽  
Total Hip ◽  
Number Of Patients ◽  
Custom Made

Background. The number of patients undergoing hip arthroplasty revision is constantly growing. Especially, complex problem is extensive loss of bone stock and pelvic discontinuity that requires reconstruction. Case report. The paper presented a 50-year old patient, who ten years ago underwent a total cement artrhroplasty of the left hip. A year after the primary operation the patient had difficulties in walking without crutches. Problems intensified in the last five years, the patient had severe pain, totally limited movement in the left hip and could not walk at all. Radiographically, we found loose femoral component, massive loss of bone stock of proximal femur, acetabular protrusion and a consequent pelvic discontinuity. Clinically, a completely disfunctional left hip joint was registered (Harris hip score - 7.1). We performed total rearthroplasty by a custom- made Waldemar Link total hip prosthesis with acetabular antiprotrusio cage and compensation of bone defects with a graft from the bone bank. A year after the operation, we found clinically an extreme improvement in Harris hip score - 87.8. Radiographically, we found stability of implanted components, a complete graft integration and bone bridging across the site of pelvic discontinuity. Conclusion. Pelvic discontinuity and massive loss of proximal femoral bone stock is a challenging and complex entity. Conventional prostheses cannot provide an adequate fixation and stability of the hip. Application of custom-made prosthesis (measured specifically for a patient) and additional alografting bone defects is a good method in revision surgery after unsuccessful hip arthroplasty with extensive bone defects.

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