A Mutlti-Scale FE Modeling Approach to Investigate the Contact Mechanics and Interfacial Stress of a Low Stiffness Porous Metal-Backed Acetabular Cup

2008 ◽  
Author(s):  
Zhibin Fang ◽  
Barbara J. Kralovic ◽  
Yang W. Son ◽  
Danny L. Levine ◽  
Todd S. Johnson
Keyword(s):  
Hip Arthroplasty ◽  
Load Transfer ◽  
Bone Ingrowth ◽  
High Stress ◽  
Stress Shielding ◽  
Porous Metal ◽  
Interfacial Stress ◽  
Polyethylene Liner ◽  
Acetabular Cup ◽  
Metal Shell

In modern Total Hip Arthroplasty (THA), modular metal-backed acetabular cups consisting of a metal shell backing with porous coatings for fixation and a modular polyethylene liner for articulation are currently the most widely used cementless acetabular cups. Modular acetabular cups give surgeons the flexibility to change femoral head size, liner offset, and liner-lip buildup during hip arthroplasty as well as the ability to change the liner without removing a bone-ingrowth metal shell during revision surgery. However, concerns have been noted with modular metal backed acetabular cups. Poor locking mechanisms have been blamed for backside wear and polyethylene liner dislodgement as well as debris which may lead to osteolysis [1]. In addition, the study of the load transfer around acetabular cups has shown that a stiff metal backing generates high stress peaks around the acetabular rim while it reduces the stresses transferred at the central part of acetabulum potentially causing stress shielding at the dome of acetabulum [2].

scholarly journals Treatment of Acetabular Defects with Porous Metal Augments in Revision Hip Surgery

PRILOZI ◽  
2019 ◽  
Vol 40 (2) ◽  
pp. 33-39
Author(s):  
Jasmin Ciriviri ◽  
Zoran Nestorovski ◽  
Darko Talevski ◽  
Tode Vranishkovski ◽  
Hristijan Kostov
Keyword(s):  
Hip Arthroplasty ◽  
Bone Ingrowth ◽  
Weight Bearing ◽  
Porous Metal ◽  
Lateral Approach ◽  
Revision Hip Arthroplasty ◽  
Acetabular Cup ◽  
Local Bone ◽  
Acetabular Defects

Abstract Porous metal augments have been used successfully for management of large acetabular defects during revision hip arthroplasty. This study analyzes and compares the clinical and radiographic outcomes of porous metal augments in cemented and uncemented acetabular revisions, all performed at the same institution. In the period 2015-2017, 36 patients with 37 large acetabular defects were treated with porous metal augments in cemented and uncemented acetabular revisions. Postoperatively, patients were monitored for two years on average period of 24-36 months. Acetabular augments were used when preoperative and intraoperative findings indicated the presence of large acetabular defects that can hinder the stability of the revision implants. We used lateral approach, 36 mm femoral head, and cementless or cemented acetabular cup depending on local bone quality. Postoperatively, all patients followed total hip arthroplasty precautions, with weight bearing as tolerated regimen with use of crutches during 6 weeks after surgery. The follow-up was radiological and clinical. We used HHS. At a mean follow-up of two years (range 24-36 months) one patient had reinfection and one patient had infection. None of the patients shown signs of aseptic augment or acetabular cup loosening. Porous metal augments show comparable excellent radiographic and clinical short-term outcomes, when combined with cemented or uncemented cups in revision hip arthroplasty. They allow good bone ingrowth, adequate implant contact and good stability. Complications were related to infection and not related to the augments itself.

Failure Mode of Polyethylene Liner in Total Hip Arthroplasty with Harris-Galante II Acetabular Cup

2004 ◽  
Vol 39 (7) ◽  
pp. 766
Author(s):  
Byung Woo Min ◽  
Ki Cheol Bae ◽  
Kyung Jae Lee ◽  
Sung Won Sohn ◽  
Chul Hyung Kang
Keyword(s):  
Total Hip Arthroplasty ◽  
Failure Mode ◽  
Hip Arthroplasty ◽  
Polyethylene Liner ◽  
Acetabular Cup ◽  
Total Hip

Do Cemented Dual-Mobility Cups Confer Stability for Patients at High Risk of Dislocation in Revision Total Hip Arthroplasty?

2018 ◽  
Vol 02 (02) ◽  
pp. 088-091 ◽  
Author(s):  
Perry Evangelista ◽  
Kamil Okroj ◽  
Darren Plummer ◽  
Craig Della Valle ◽  
Ran Schwarzkopf
Keyword(s):  
High Risk ◽  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Revision Surgery ◽  
Revision Total Hip Arthroplasty ◽  
Acetabular Cup ◽  
Metal Shell ◽  
Dual Mobility ◽  
Total Hip

AbstractDislocation is among the most commonly reported complications following revision total hip arthroplasty. Dual-mobility bearings may lower the risk of dislocation. The authors report the results of a multicenter study evaluating the use of a dual-mobility acetabular cup design that was cemented into a metal shell as part of complex acetabular reconstructions or in cases where the risk of dislocation was felt to be high, such as isolated bearing exchanges. Eighteen patients were identified for being at high risk of dislocation who underwent cementation of a dual-mobility shell that is specifically made for cementation, into a fully porous metal revision acetabular cup (10 patients) or into a well-fixed cup at the time of revision without removal of the existing acetabular component (eight patients). Patients were assessed clinically and radiographically at a minimum of 2 years for the evidence of dislocation, revision surgery, and implant loosening. At a mean of 36 months (range, 25–56 months), one patient died and one was lost to follow-up. There were no known cases of hip dislocation. There was one repeat revision, for a deep infection treated with irrigation and debridement. The mean preoperative Harris Hip Score of 46 (range, 40–79) improved to a mean of 65 points (range, 41–97) at the most recent evaluation. Acetabular components were retained in 8 out of 18 cases and the dual-mobility shell was cemented into it. Cementation of a dual-mobility cup into a shell at the time of a revision surgery is a safe and reliable construct at minimum of 2 years for patients at high risk of dislocation. There were no complications related to the cementation of the cup into the metal shell. Longer follow-up is required to further assess the durability of this construct.

scholarly journals Metaphyseal anchoring short stem hip arthroplasty provides a more physiological load transfer: a comparative finite element analysis study

2020 ◽  
Author(s):  
Shuang G Yan ◽  
Yan Chevalier ◽  
Fanxiao Liu ◽  
Xingyi Hua ◽  
Anna Schreiner ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Load Transfer ◽  
High Stress ◽  
Short Stem ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Total Hip

Abstract Background: Short stem total hip arthroplasty (SHA) preserves femoral bone stock and is supposed to provide a more natural load transfer compared to standard stem total hip arthroplasty (THA). As comparative biomechanical reference data are rare we used a finite element analysis (FEA) approach to compare cortical load transfer after implantations of a metaphyseal anchoring short and standard stem in native biomechanical femora. Methods: The subject specific finite element models of biomechanical femora, one native and two with implanted metaphyseal anchoring SHA (Metha, B.Braun Aesculap) and standard THA (CLS, Zimmer-Biomet), were generated from computed tomography datasets. The loading configuration was performed with an axial force of 1400 N. Von Mises stress was used to investigate the change of cortical stress distribution. Results: Compared to the native femur, a considerable reduction of cortical stress was recorded after implantation of SHA and standard THA. The SHA showed less reduction proximally with a significant higher metaphyseal cortical stress compared to standard THA. Moreover, the highest peak stresses were observed metaphyseal for the SHA stem while for the standard THA high stress pattern was observed more distally. Conclusions: Both, short and standard THA, cause unloading of the proximal femur. However, the metaphyseal anchoring SHA features a clearly favorable pattern in terms of a lower reduction proximally and improved metaphyseal loading, while standard THA shows a higher proximal unloading and more distal load transfer. These load pattern implicate a reduced stress shielding proximally for metaphyseal anchoring SHA stems and might be able to translate in a better bone preservation.

scholarly journals Short stem hip arthroplasty provides a more physiological load transfer: a comparative finite element analysis study

2020 ◽  
Author(s):  
Shuang G Yan ◽  
Yan Chevalier ◽  
Fanxiao Liu ◽  
Xingyi Hua ◽  
Anna Schreiner ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Load Transfer ◽  
High Stress ◽  
Short Stem ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Total Hip

Abstract Background: Short stem total hip arthroplasty (SHA) preserves femoral bone stock and is supposed to provide a more natural load transfer compared to standard stem total hip arthroplasty (THA). As comparative biomechanical reference data are rare we used a finite element analysis (FEA) approach to compare cortical load transfer after implantations of a cementless short and standard stem in native biomechanical femora.Methods: The subject specific finite element models of biomechanical femora, one native and two with implanted SHA (Metha, B.Braun Aesculap) and standard THA (CLS, Zimmer-Biomet), were generated from computed tomography datasets. The loading configuration was performed with an axial force of 1400 N. Von Mises stress was used to investigate the change of cortical stress distribution.Results: Compared to the native femur, a considerable reduction of cortical stress was recorded after implantation of SHA and standard THA. The SHA showed less reduction proximally with a significant higher metaphyseal cortical stress compared to standard THA. Moreover, the highest peak stresses were observed metaphyseal for the SHA stem while for the standard THA high stress pattern was observed more distally.Conclusions: Both, short and standard THA, cause unloading of the proximal femur. However, SHA features a clearly favorable pattern in terms of a lower reduction proximally and improved metaphyseal loading, while standard THA shows a higher proximal unloading and more distal load transfer. These load pattern implicate a reduced stress shielding proximally for SHA and might be able to translate in a better bone preservation.

Experimental and Finite Element Investigation of Cementless Cup/Bone Interface After Total Hip Arthroplasty

2004 ◽  
Author(s):  
Ivan Zivkovic ◽  
Farid Amirouche ◽  
Francisco Romero ◽  
Mark Gonzalez
Keyword(s):  
Finite Element ◽  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Bone Ingrowth ◽  
Element Model ◽  
Loading Conditions ◽  
Acetabular Cup ◽  
Bone Interface ◽  
Total Hip ◽  
Cementless Cup

Permanent fixation of a cementless total hip arthroplasty requires bone ingrowth into the femoral and acetabular components. Early micromotion at the acetabular cup/bone interface can preclude ingrowth threatening long term fixation. To better characterize micromotion of the interface under loading conditions, an experimental and finite element (FE) study was undertaken. In this study cadaver hemi-pelvises were implanted with cementless acetabular cups and subjected to cyclical axial load and torque. Detailed finite element model, validated with experimental results, was developed to further analyze the conditions affecting the initial stability and loosening of the interface for different loading conditions.

Interface biomechanics of the Anca Dual Fit hip stem: An in vitro experimental study

2001 ◽  
Vol 215 (6) ◽  
pp. 555-564 ◽  
Author(s):  
L Monti ◽  
L Cristofolini ◽  
M Viceconti
Keyword(s):  
Load Transfer ◽  
Bone Ingrowth ◽  
Stress Shielding ◽  
Primary Stability ◽  
Stair Climbing ◽  
Term Stability ◽  
Long Term Stability ◽  
Cemented Stem

The Anca Dual Fit hip stem (Cremascoli Wright, Milan, Italy) is a partially cemented stem developed to overcome the drawbacks of both cemented and uncemented fixations. Its design was based on the hypothesis that partial cementing would ensure the primary stability necessary to allow bone ingrowth on the cement-free stem surfaces. At the same time, the limitation of the cement to the proximal regions would prevent stress-shielding by increasing proximal load transfer. After finite element (FE) simulations and in vitro primary stability assessment, an analysis of the long-term stability of the Anca Dual Fit stem was necessary to conclude the preclinical testing. Three stems were implanted in composite femurs and subjected to testing for 1 × 106 cycles, each cycle reproducing the activity of stair climbing. The simulation was designed so as to replicate the physiological loading in a simplified, yet relevant way for this test. Various measurements were collected before, during and after the test in order to give exhaustive information on the response of the implant to long-term, cyclic loading. The present study confirmed the positive results of previous investigations, and proved that the Anca Dual Fit stem has excellent long-term stability; therefore successful clinical outcomes are predicted.

Stress and Strain Distribution in the Bone Surrounding a New Design of Dental Implant: A Comparison with a Threaded Branemark Type Implant

1993 ◽  
Vol 207 (3) ◽  
pp. 133-138 ◽  
Author(s):  
S E Clift ◽  
J Fisher ◽  
C J Watson
Keyword(s):  
Stress Concentration ◽  
Dental Implant ◽  
Load Transfer ◽  
Bone Ingrowth ◽  
High Stress ◽  
Neck Region ◽  
Lateral Loading ◽  
Porous Coating ◽  
Stress And Strain ◽  
Bonded Interface

The stress and strain distributions in the bone surrounding a new dental implant, designed specifically for use with a bioactive porous coating and thus having a fully bonded interface to the bone, have been analysed. The new implant geometry was slightly tapered, with deep concentric grooves to allow bone ingrowth and load transfer, and had a parallel cylindrical section at the neck. The results have been compared with stress and strain predictions in the bone surrounding a ‘Branemark type’ threaded implant with a fully bonded interface. Under axial loading both implant types produced similar stress and strain distributions with a higher level of stress in the cortical bone surrounding the neck of the implant. Under lateral loading a high stress concentration was found in the neck region of both implants, but this was lower around the neck of the new design compared with the threaded implant. When the new implant was surrounded by cancellous bone, the reduction in the stress concentration was up to 50 per cent. This reduction should help to reduce fatigue failure and bone resorption in this area under lateral loading.

scholarly journals High risk of hip dislocation following polyethylene liner exchange in total hip arthroplasty—is cup revision necessary?

2020 ◽  
Vol 140 (11) ◽  
pp. 1837-1845
Author(s):  
D. Dammerer ◽  
F. Schneider ◽  
T. Renkawitz ◽  
D. Putzer ◽  
M. Bogensperger ◽  
...  
Keyword(s):  
High Risk ◽  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Revision Surgery ◽  
Hip Dislocation ◽  
Polyethylene Liner ◽  
Acetabular Cup ◽  
Total Hip ◽  
Risk Increase ◽  
Cup Revision

Abstract Purpose Polyethylene (PE) wear remains a common reason for revision surgery following total hip arthroplasty (THA). An established treatment method is isolated liner exchange in a well-fixed acetabular cup and entails a known high risk of hip dislocation after revision surgery. The purpose of this retrospective study was to determine the rate of hip dislocation after liner exchange. Methods Patients were included if (1) the PE liner was removable, (2) the acetabular shell was stable with acceptable orientation, (3) no osteolysis around the acetabular cup was found and (4) no dislocation of the THA occurred before revision surgery. We reviewed medical histories and performed radiological measurements using Einzel-Bild-Röntgen-Analyse (EBRA) software. EBRA measurements and statistical investigations were performed by two independent investigators. Results A total of 82 patients were included in our study. Mean follow-up was six (range: 3.6–9.9) years. In 13 (15.8%) patients THA dislocations occurred at a mean postoperative period of 20.2 (range: 1–44) weeks after revising the PE liner. This is equivalent to an absolute risk increase of 16% after revision surgery, which results in a number needed to harm of 6. This means that every sixth patient with isolated liner exchange can expect to experience dislocation due to wear. Conclusion In conclusion, isolated exchange of the polyethylene liner because of wear showed a high risk of dislocation and further cup revision. Our results suggest that the threshold for revising well-fixed components in the case of liner wear should be lowered. Trial Registration number and date of registration Number: 20140710-1012 and Date: 2016-03-09.

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