scholarly journals Stress occurring in the friction node of elements in the total knee endoprosthesis

2015 ◽  
Vol 14 (2) ◽  
pp. 41-48
Author(s):  
Marcin Nabrdalik ◽  
Keyword(s):  
Total Knee ◽  
Knee Endoprosthesis

scholarly journals Influence of Different Patellofemoral Design Variations Based on Genesis II Total Knee Endoprosthesis on Patellofemoral Pressure and Kinematics

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Ulf G. Leichtle ◽  
Barbara Lange ◽  
Yvonne Herzog ◽  
Peter Schnauffer ◽  
Carmen I. Leichtle ◽  
...  
Keyword(s):  
Original Design ◽  
Interindividual Differences ◽  
Knee Simulator ◽  
Custom Made ◽  
Total Knee ◽  
Genesis Ii ◽  
Design Options ◽  
Patellofemoral Kinematics ◽  
Patellofemoral Pressure ◽  
Knee Endoprosthesis

In total knee arthroplasty (TKA), patellofemoral groove design varies greatly and likely has a distinct influence on patellofemoral biomechanics. To analyse the selective influence, five patellofemoral design variations were developed based on Genesis II total knee endoprosthesis (original design, being completely flat, being laterally elevated, being medially elevated, and both sides elevated) and made from polyamide using rapid prototyping. Muscle-loaded knee flexion was simulated on 10 human knee specimens using a custom-made knee simulator, measuring the patellofemoral pressure distribution and tibiofemoral and patellofemoral kinematics. The measurements were carried out in the native knee as well as after TKA with the 5 design prototypes. The overall influence of the different designs on the patellofemoral kinematics was small, but we found detectable effects for mediolateral tilt (p<0.05 for 35°–80° flexion) and translation of the patella (p<0.045 for 20°–65° and 75°–90°), especially for the completely flat design. Considering patellofemoral pressures, major interindividual differences were seen between the designs, which, on average, largely cancelled each other out. These results suggest that the elevation of the lateral margin of the patellofemoral groove is essential for providing mediolateral guidance, but smooth contouring as with original Genesis II design seems to be sufficient. The pronounced interindividual differences identify a need for more patellofemoral design options in TKA.

scholarly journals Analysis of inpatient costs in patients with knee osteoarthritis treated by implantation of total condylar knee endoprosthesis

2018 ◽  
Vol 75 (10) ◽  
pp. 989-997
Author(s):  
Ana Pejcic ◽  
Aleksandar Radunovic ◽  
Maja Vulovic
Keyword(s):  
Total Knee Replacement ◽  
Knee Osteoarthritis ◽  
Knee Replacement ◽  
Cost Driver ◽  
Inpatient Cost ◽  
Insurance Fund ◽  
Cost Drivers ◽  
Total Knee ◽  
Specific Material ◽  
Knee Endoprosthesis

Background/Aim. Total knee replacement is an elective and high cost surgical procedure which is performed more frequently as a result of increasing prevalence of knee osteoarthritis. The aim of this study was to provide insight into the value and structure of inpatient costs associated with total knee replacement in Serbia. Methods. This study was conducted as an in-depth, bottom-up, retrospective, case series analysis of services consumption patterns and costs associated with inpatient treatment of patients with knee osteoarthritis by implantation of primary total condylar knee endoprosthesis from perspective of the national Republic Health Insurance Fund. We obtained data on 97 patients treated with primary unilateral or bilateral total knee replacement in 2014 at the Clinic for Orthopaedic Surgery and Traumatology of the Military Medical Academy in Belgrade, a tertiary health care university hospital. Results. Mean age of entire study sample was 67.89 years. Majority of patients (60 patients; 61.9%) had unilateral implantation of total condylar knee endoprosthesis. Bilateral implantation was performed in 37 (38.1%) patients. Mean total inpatient cost per patient for both unilateral and bilateral implantation of total condylar knee endoprosthesis was EUR 2,709.1, ranging from EUR 1,685.2 to EUR 5,356.6. Mean total inpatient cost per patient was EUR 2,093.8 for unilateral implantation and EUR 3,706.8 for bilateral implantation. Two major cost drivers were surgery specific material and surgery. Cost of implants was the highest single cost driver in all observed groups of patients. Conclusion. Our findings imply that inpatient costs associated with implantation of primary total condylar knee endoprosthesis are substantial. It seems that the most important cost drivers are surgery and surgery specific material, with implants being the highest single cost driver. Further research should be focused on analyzing factors that influence these costs in order to develop effective strategies which could contribute to substantial savings in the future.

scholarly journals Navigated Cementless Total Knee Arthroplasty - Medium-Term Clinical and Radiological Results§

2012 ◽  
Vol 6 (1) ◽  
pp. 160-163 ◽  
Author(s):  
Jan P Schüttrumpf ◽  
Peter Balcarek ◽  
Stephan Sehmisch ◽  
Stephan Frosch ◽  
Martin M Wachowski ◽  
...  
Keyword(s):  
Navigation System ◽  
Pure Titanium ◽  
Medium Term ◽  
Press Fit ◽  
Radiological Results ◽  
Total Knee ◽  
Clinical And Radiological Results ◽  
Cementless Implantation ◽  
Knee Endoprosthesis

Purpose: The objective of this prospective study was to evaluate the medium-term clinical and radiological results after navigated cementless implantation, without patella resurfacing, of a total knee endoprosthesis with tibial and femoral press-fit components, with a focus on survival rate and clinical outcome. The innovation is the non-cemented fixation together with the use of a navigation system. Scope and Methods: Sixty patients with gonarthrosis were included consecutively in this study. In all cases, the cementless Columbus total knee endoprosthesis with a coating out of pure titanium was implanted, using a navigation system. The Knee Society Score showed a statistically significant increase from 75 (± 21.26) before surgery to 180 (± 16.15) after a mean follow-up of 5.6 (± 0.25) years. The last radiological examination revealed no osteolysis. No radiolucent lines were seen at any time in the area of the femoral prosthetic components. In the tibial area, radiolucent lines were seen in 24.4 % of the cases, mostly in the distal uncoated part of the stem. During follow-up, no prosthesis had to be replaced because of aseptic loosening while in 2 cases revision surgery was necessary due to septic loosening and in 1 case due to unexplainable pain. Results and Conclusions: Navigated cementless implantation of the Columbus total knee endoprosthesis yielded good clinical and radiological results in the medium term. The excellent radiological osteointegration of the prosthetic components, coated with a microporous pure titanium layer and implanted with a press-fit technique, should be emphasized.

Assessment of Loosening and Rotational Malalignment Following Knee Endoprosthesis or Other Surgical Components

2018 ◽  
Vol 22 (04) ◽  
pp. 435-443 ◽  
Author(s):  
Marc-André Weber ◽  
Christoph Rehnitz ◽  
Wolfram Mittelmeier ◽  
John Carrino ◽  
Kolja Thierfelder ◽  
...  
Keyword(s):  
Major Complication ◽  
Relevant Information ◽  
Point Of View ◽  
Coronal Alignment ◽  
Rotational Malalignment ◽  
Economic Implications ◽  
Correct Placement ◽  
Total Knee ◽  
Surgery Rates ◽  
Knee Endoprosthesis

AbstractTotal knee arthroplasty (TKA) has significant medical and economic implications. The correct placement of the femoral and tibial components is vital to ensure a functional knee and also low failure and revision surgery rates. This article provides the most relevant information regarding knee endoprosthesis from a radiologic point of view. Basic information on the recommended alignment of the femoral and tibial components in TKA and how to measure them are discussed. We then present the most important axial plane rotational references for the femoral and the tibial components. The optimal coronal alignment, illustrating the axes of the lower limb, and loosening as the major complication are also discussed. Finally, we offer a detailed example of rotational assessment.

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