scholarly journals Urinary Prothrombin Fragment 1+2 in relation to Development of Non-Symptomatic and Symptomatic Venous Thromboembolic Events following Total Knee Replacement

Thrombosis ◽  
2011 ◽  
Vol 2011 ◽  
pp. 1-6
Author(s):  
Lars C. Borris ◽  
Morten Breindahl ◽  
Michael R. Lassen ◽  
Ákos F. Pap
Keyword(s):  
Total Knee Replacement ◽  
Knee Replacement ◽  
Operative Procedure ◽  
Clinical Test ◽  
Prothrombin Fragment ◽  
Venous Thromboembolic Events ◽  
Venous Thromboembolic ◽  
Patients At Risk ◽  
Total Knee

Prothrombin fragment 1+2 is excreted in urine (uF1+2) as a result of in vivo thrombin generation and can be a marker of coagulation status after an operative procedure. This study compared uF1+2 levels in patients with symptomatic and non-symptomatic venous thromboembolism (VTE) after total knee replacement (TKR) and in event-free sex- and age-matched controls. Significantly higher median uF1+2 levels were seen in the VTE patients on days 1, 3, and the day of venography (mostly day 7) after TKR compared with controls. The uF1+2 levels tended to be high in some patients with symptomatic VTE; however, the discriminatory efficacy of the test could not be evaluated. In conclusion, this study showed that patients with VTE tend to have significantly higher uF1+2 levels compared with patients without events between days 1 and 7 after TKR surgery. Measurement of uF1+2 could provide a simple, non-invasive clinical test to identify patients at risk of VTE.

Calculated Axial Forces at the Knee in Total Knee Replacement Patients During Chair and Stair Activities

2012 ◽  
Author(s):  
Hannah J. Lundberg ◽  
Christopher B. Knowlton ◽  
Diego Orozco ◽  
Markus A. Wimmer
Keyword(s):  
Total Knee Replacement ◽  
Knee Replacement ◽  
Contact Forces ◽  
Force Output ◽  
Stair Ascent ◽  
Numeric Model ◽  
Axial Forces ◽  
Joint Contact ◽  
Total Knee

Knowledge of in vivo knee contact forces is essential for evaluating total knee replacement (TKR) designs. This is particularly true for activities other than walking, because there is still a limited understanding of its impact on wear. It has been shown that wear scars from retrieved implants have obvious differences compared with simulator tested components in both size of worn area and in damage mode. The divergence could be related to the omission of other activities than walking when testing components in the simulator. The purpose of this study was to use a parametric numerical model for predicting joint contact forces during stair ascent/descent and chair sitting/rising and compare those to measured forces from a database. We hypothesized that the contact force output of the numeric model would be similar to the measured forces.

The use of synthetic ligaments in the design of an enhanced stability total knee joint replacement

2018 ◽  
Vol 232 (3) ◽  
pp. 282-288
Author(s):  
Michael D Stokes ◽  
Brendan C Greene ◽  
Luke W Pietrykowski ◽  
Taylor M Gambon ◽  
Caroline E Bales ◽  
...  
Keyword(s):  
Total Knee Replacement ◽  
Range Of Motion ◽  
Knee Replacement ◽  
Physical Prototype ◽  
Synthetic Ligament ◽  
Total Knee ◽  
Replacement System ◽  
The Stability ◽  
Replacement Design

Current total knee replacement designs work to address clinically desired knee stability and range of motion through a balance of retained anatomy and added implant geometry. However, simplified implant geometries such as bearing surfaces, posts, and cams are often used to replace complex ligamentous constraints that are sacrificed during most total knee replacement procedures. This article evaluates a novel total knee replacement design that incorporates synthetic ligaments to enhance the stability of the total knee replacement system. It was hypothesized that by incorporating artificial cruciate ligaments into a total knee replacement design at specific locations and lengths, the stability of the total knee replacement could be significantly altered while maintaining active ranges of motion. The ligament attachment mechanisms used in the design were evaluated using a tensile test, and determined to have a safety factor of three with respect to expected ligamentous loading in vivo. Following initial computational modeling of possible ligament orientations, a physical prototype was constructed to verify the function of the design by performing anterior/posterior drawer tests under physiologic load. Synthetic ligament configurations were found to increase total knee replacement stability up to 94% compared to the no-ligament case, while maintaining total knee replacement flexion range of motion between 0° and 120°, indicating that a total knee replacement that incorporates synthetic ligaments with calibrated location and lengths should be able to significantly enhance and control the kinematic performance of a total knee replacement system.

In vivo measurement of total knee replacement wear

The Knee ◽  
2004 ◽  
Vol 11 (3) ◽  
pp. 183-187 ◽  
Author(s):  
C.F Kellett ◽  
A Short ◽  
A Price ◽  
H.S Gill ◽  
D.W Murray
Keyword(s):  
Total Knee Replacement ◽  
Knee Replacement ◽  
In Vivo Measurement ◽  
Total Knee

Computational wear prediction of a total knee replacement from in vivo kinematics

2005 ◽  
Vol 38 (2) ◽  
pp. 305-314 ◽  
Author(s):  
Benjamin J. Fregly ◽  
W.Gregory Sawyer ◽  
Melinda K. Harman ◽  
Scott A. Banks
Keyword(s):  
Total Knee Replacement ◽  
Knee Replacement ◽  
Wear Prediction ◽  
In Vivo Kinematics ◽  
Total Knee

Dynamically Consistent Whole-Body Modeling and Simulation Can Reasonably Predict In Vivo Knee Loads

2015 ◽  
Author(s):  
Matthew J. Adams ◽  
Cameron J. Turner ◽  
Anne K. Silverman
Keyword(s):  
Total Knee Replacement ◽  
Modeling And Simulation ◽  
Knee Replacement ◽  
Whole Body ◽  
Knee Replacement Surgery ◽  
Replacement Surgery ◽  
Knee Loading ◽  
Active Lifestyles ◽  
Total Knee

Total knee replacement is a viable treatment for end-stage knee arthritis. With a greater number of younger patients opting for total knee replacement surgery, their increasingly active lifestyles will result in higher wear rates while decreasing the life expectancy of the tibial insert component of the knee replacement implant. In response to the eventuality of patients with more active lifestyles requiring knee replacement surgery, this research proposed to accurately estimate in vivo knee loading over a gait cycle using a dynamically consistent whole-body modeling and simulation method. However, medical treatment based on modeling and simulation must be validated before clinical application becomes feasible. Estimates for knee loading were compared to publicly-available in vivo knee loading measurements from a telemetric implant [1]. A whole-body musculoskeletal modeling approach was used to simulate the gait cycle of a person who had undergone total knee replacement surgery. This approach was used to calculate net knee joint contact forces. Results suggest that generic whole-body modeling and hybrid forward dynamic simulation techniques for estimating knee joint loads may become clinically feasible in the near future.

scholarly journals Evaluation of a Surrogate Contact Model in Force-Dependent Kinematic Simulations of Total Knee Replacement

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Marco A. Marra ◽  
Michael S. Andersen ◽  
Michael Damsgaard ◽  
Bart F. J. M. Koopman ◽  
Dennis Janssen ◽  
...  
Keyword(s):  
Total Knee Replacement ◽  
Knee Replacement ◽  
Reference Model ◽  
Knee Kinematics ◽  
Contact Model ◽  
Related Factors ◽  
Joint Contact ◽  
Total Knee ◽  
Parametric Analyses

Knowing the forces in the human body is of great clinical interest and musculoskeletal (MS) models are the most commonly used tool to estimate them in vivo. Unfortunately, the process of computing muscle, joint contact, and ligament forces simultaneously is computationally highly demanding. The goal of this study was to develop a fast surrogate model of the tibiofemoral (TF) contact in a total knee replacement (TKR) model and apply it to force-dependent kinematic (FDK) simulations of activities of daily living (ADLs). Multiple domains were populated with sample points from the reference TKR contact model, based on reference simulations and design-of-experiments. Artificial neural networks (ANN) learned the relationship between TF pose and loads from the medial and lateral sides of the TKR implant. Normal and right-turn gait, rising-from-a-chair, and a squat were simulated using both surrogate and reference contact models. Compared to the reference contact model, the surrogate contact model predicted TF forces with a root-mean-square error (RMSE) lower than 10 N and TF moments lower than 0.3 N·m over all simulated activities. Secondary knee kinematics were predicted with RMSE lower than 0.2 mm and 0.2 deg. Simulations that used the surrogate contact model ran on average three times faster than those using the reference model, allowing the simulation of a full gait cycle in 4.5 min. This modeling approach proved fast and accurate enough to perform extensive parametric analyses, such as simulating subject-specific variations and surgical-related factors in TKR.

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