Wear of a Mobile Bearing Uni-Compartmental Knee Replacement Prosthesis: A Comparison of In Vitro and In Vivo Wear Rates

2011 ◽  
pp. 185-194
Author(s):  
P. J. Ellison ◽  
A. Traynor ◽  
B. P. Casey ◽  
S. N. Collins
Keyword(s):  
Knee Replacement ◽  
Mobile Bearing ◽  
Wear Rates ◽  
Replacement Prosthesis

Wear of a Mobile Bearing Uni-Compartmental Knee Replacement Prosthesis: A Comparison of In Vitro and In Vivo Wear Rates

2011 ◽  
Vol 8 (2) ◽  
pp. 103328 ◽  
Author(s):  
P. J. Ellison ◽  
A. Traynor ◽  
B. P. Casey ◽  
S. N. Collins ◽  
K. Trier ◽  
...  
Keyword(s):  
Knee Replacement ◽  
Mobile Bearing ◽  
Wear Rates ◽  
Replacement Prosthesis

The influence of shape and sliding distance of femoral head movement loci on the wear of acetabular cups in total hip arthroplasty

2002 ◽  
Vol 216 (6) ◽  
pp. 393-402 ◽  
Author(s):  
D Bennett ◽  
J F Orr ◽  
D E Beverland ◽  
R Baker
Keyword(s):  
Femoral Head ◽  
Aspect Ratio ◽  
Hip Joint ◽  
Wear Rates ◽  
Total Hip ◽  
Aspect Ratios ◽  
Average Aspect Ratio ◽  
Sliding Distance

Wear of the polyethylene acetabular component is the most serious threat to the long-term success of total hip replacements (THRs). Greatly reduced wear rates have been reported for unidirectional, compared to multidirectional, articulation in vitro. This study considers the multidirectional motions experienced at the hip joint as described by movement loci of points on the femoral head for individual THR patients. A three-dimensional computer program determined the movement loci of selected points on the femoral head for THR patients and normal subjects using kinematic data obtained from gait analysis. The sizes and shapes of these loci were quantified by their sliding distances and aspect ratios with substantial differences exhibited between individual THR patients. The average sliding distances ranged from 10.0 to 18.1 mm and the average aspect ratios of the loci ranged from 2.5 to 9.2 for the THR patients. Positive correlations were found between wear rate and average sliding distance, the inverse of the average aspect ratio of the loci and the product of the average sliding distance and the inverse of the average aspect ratio of the loci. Patients with a normal hip joint range of motion produce multidirectional motion loci and tend to experience more wear than patients with more unidirectional motion loci. Differing patterns of multidirectional motion at the hip joint for individual THR patients may explain widely differing wear rates in vivo.

scholarly journals Knee Wear Assessment: 3D Scanners Used as a Consolidated Procedure

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2349 ◽  
Author(s):  
Saverio Affatato ◽  
Maria Cristina Valigi ◽  
Silvia Logozzo
Keyword(s):  
Clinical Performance ◽  
Wear Behavior ◽  
Wear Test ◽  
Mobile Bearing ◽  
Clinical Problem ◽  
Material Loss ◽  
Optical Scanners ◽  
Wear Rates ◽  
3D Scanners

It is well known that wear occurring in polyethylene menisci is a significant clinical problem. At this regard, wear tests on biomaterials medical devices are performed in order to assess their pre-clinical performance in terms of wear, durability, resistance to fatigue, etc. The objective of this study was to assess the wear of mobile total knee polyethylene inserts after an in vitro wear test. In particular, the wear behavior of mobile bearing polyethylene knee configurations was investigated using a knee joint wear simulator. After the completion of the wear test, the polyethylene mobile menisci were analyzed through a consolidated procedure by using 3D optical scanners, in order to evaluate the 3D wear distribution on the prosthesis surface, wear depths, wear rates, amount of material loss and contact areas. The results in terms of wear rates and wear volumes were compared with results of gravimetric tests, finding equivalent achievements.

In-Vitro Study of Backside Wear Mechanism on Mobile Knee Bearing Components

2005 ◽  
Author(s):  
Sara A. Atwood ◽  
Francis E. Kennedy ◽  
John H. Currier ◽  
Douglas W. Van Citters ◽  
John P. Collier
Keyword(s):  
Bone Cement ◽  
In Vitro Study ◽  
Mobile Bearing ◽  
Fixation Method ◽  
Porous Coating ◽  
Third Body ◽  
Rotating Platform ◽  
Backside Wear

Backside wear in the form of scratching and pitting observed on a series of mobile bearing rotating platform knee retrievals (n = 100) appears to be indicative of third body wear. The appearance of scratching and pitting on the backside does not correlate with duration in vivo or with linear backside wear measurements, but there is a weak correlation with fixation method indicating that some of the third body debris may be bone cement. Tribological tests representing rotation and fretting in the knee were run with bone cement, bone chips, and metal porous coating beads placed as third bodies in the contact. Results with bone cement show scratches similar to those found on retrievals.

A Direct Comparision of Patient and Simulator Total Knee Replacement Kinematics

2001 ◽  
Author(s):  
John D. DesJardins ◽  
Scott A. Banks ◽  
Lisa C. Benson ◽  
Martine LaBerge
Keyword(s):  
Total Knee Replacement ◽  
Knee Replacement ◽  
Gold Standard ◽  
Patient Population ◽  
International Standards ◽  
Wear Testing ◽  
Wear Simulation ◽  
Total Knee

Abstract The need to critically evaluate the efficacy of current total knee replacement (TKR) wear testing methodologies is great. Proposed international standards for TKR wear simulation have been drafted, yet their validity continues to be debated. The “gold standard” to which all wear testing methodologies should be compared is the measured in vivo TKR performance of the patient population. With the exception of retrieval analyses, few detailed comparisons of in-vitro vs. in-vivo TKR performance have been performed to date. The current study compares simulator TKR wear testing kinematics to measured in vivo TKR kinematics to evaluate the validity of the proposed ISO force-controlled wear testing methodology.

Wear Simulation of Metal on Metal Hip Replacements: An Analytical Approach

2012 ◽  
Author(s):  
Lorenza Mattei ◽  
Francesca Di Puccio ◽  
Enrico Ciulli
Keyword(s):  
Hip Replacement ◽  
Experimental Tests ◽  
Wear Model ◽  
Wear Rates ◽  
Metal On Metal ◽  
Hip Replacements ◽  
Wear Law ◽  
Implant Wear

Hip replacement failure is mainly attributable to the implant wear. Consequently preclinical wear evaluations are extremely important. As experimental tests are attractive but highly cost/time demanding, several predictive models have been proposed mainly based on finite element simulations and for metal on plastic (MoP) implants. The aim of this study is to develop a mathematical wear model of metal on metal prostheses, revision of the previous one for MoP implants, developed by the same authors. The model, based on the Archard wear law and on the Hertzian theory, was applied to compare a total (THR) and a resurfacing (RHR) hip replacement under both in vivo and in vitro gait conditions. The results were in agreement with the literature predicting wear rates significantly higher for the RHR than for the THR. The effect of the boundary conditions on wear rates/maps was also investigated and the model limitations discussed.

Induction and Differentiation of Dental Epithelium in Vivo and in Vitro

1982 ◽  
Vol 40 ◽  
pp. 142-145
Author(s):  
E. J. Kollar
Keyword(s):  
Connective Tissue ◽  
Oral Mucosa ◽  
Basal Lamina ◽  
Functional Derivatives ◽  
Specific Source ◽  
Dental Epithelium ◽  
Connective Tissue Stroma

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.

Ultrastructural Correlations between Clonal Human Tumor Colonies and in Vivo Neoplasms

1982 ◽  
Vol 40 ◽  
pp. 210-211
Author(s):  
M.J. Murphy ◽  
R.R. Price ◽  
J.C. Sloman
Keyword(s):  
Cultured Cells ◽  
Human Tumor ◽  
Cell Type ◽  
Tumor Mass ◽  
Initial Cell ◽  
Cloning Assay ◽  
Human Tumor Cloning ◽  
The Relationship

The in vitro human tumor cloning assay originally described by Salmon and Hamburger has been applied recently to the investigation of differential anti-tumor drug sensitivities over a broad range of human neoplasms. A major problem in the acceptance of this technique has been the question of the relationship between the cultured cells and the original patient tumor, i.e., whether the colonies that develop derive from the neoplasm or from some other cell type within the initial cell population. A study of the ultrastructural morphology of the cultured cells vs. patient tumor has therefore been undertaken to resolve this question. Direct correlation was assured by division of a common tumor mass at surgical resection, one biopsy being fixed for TEM studies, the second being rapidly transported to the laboratory for culture.

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