0942 Photoelastic Stress Analyses on the Tibial Insert of the Knee Prosthesis for High/Deep Flexion

Author(s):  
Mitsuaki HASEGAWA ◽  
Junichiro Takiguchi ◽  
Shunji HIROKAWA
The Knee ◽  
2021 ◽  
Vol 29 ◽  
pp. 1-8
Author(s):  
Jing-yu Zhang ◽  
Hao-ran Zhang ◽  
Dong-mu Tian ◽  
Feng Wang ◽  
Hao Zhang ◽  
...  

Author(s):  
Francisco J Lopes ◽  
António Completo ◽  
João Paulo Davim

The main purpose of this paper is to demonstrate the applicability of conventional cutting tools in the machining of a custom tibial insert of a knee prosthesis. This study also aims to reduce the roughness and minimise the production time. In this work, the optimisation of cutting strategies and parameters was achieved through the design and construction of a test-part containing the most important complex surfaces of the femoral cavities, the focus of the study. The milling was carried out in accordance with the Design Of Experiment and the Taguchi method and was performed in two stages to reduce the number of analysed factors. The achieved parameters are applied to the machining of a modelled tibial insert made of UHMWPE, using a NC machine with three axes. The initial parameters studied were the cutting method, axial and radial depth of cut, the direction of the feed and the feed rate. Three strategies were studied: two Blend, resulting in radial and spiral toolpaths, and one Parallel. According to the spiral strategy, an arithmetical mean roughness of Ra = 1.1 µm was obtained, representing an improvement of 45% relatively to the initial phase value of 2.0 µm, with the Parallel toolpath. An overall improvement of 34% in time efficiency of the finishing operation was achieved after changing the machine settings. This study supports the conclusion that high-speed milling is an expeditious process to produce customised tibial inserts.


2017 ◽  
Vol 14 (4) ◽  
pp. 495-500
Author(s):  
Toshihiro Sera ◽  
Yuya Iwai ◽  
Takaharu Yamazaki ◽  
Tetsuya Tomita ◽  
Hideki Yoshikawa ◽  
...  

2020 ◽  
Vol 9 (5) ◽  
pp. 1559 ◽  
Author(s):  
Jin-Ah Lee ◽  
Yong-Gon Koh ◽  
Kyoung-Tak Kang

(1) Background: Although knee arthroplasty or knee replacement is already an effective clinical treatment, it continues to undergo clinical and biomechanical improvements. For an increasing number of conditions, prosthesis based on an individual patient’s anatomy is a promising treatment. The aims of this review were to evaluate the clinical and biomechanical efficacy of patient-specific knee prosthesis, explore its future direction, and summarize any published comparative studies. (2) Methods: We searched the PubMed, MEDLINE, Embase, and Scopus databases for articles published prior to 1 February 2020, with the keywords “customized knee prosthesis” and “patient-specific knee prosthesis”. We excluded patient-specific instrument techniques. (3) Results: Fifty-seven articles met the inclusion criteria. In general, clinical improvement was greater with a patient-specific knee prosthesis than with a conventional knee prosthesis. In addition, patient-specific prosthesis showed improved biomechanical effect than conventional prosthesis. However, in one study, patient-specific unicompartmental knee arthroplasty showed a relatively high rate of aseptic loosening, particularly femoral component loosening, in the short- to medium-term follow-up. (4) Conclusions: A patient-specific prosthesis provides a more accurate resection and fit of components, yields significant postoperative improvements, and exhibits a high level of patient satisfaction over the short to medium term compared with a conventional prosthesis. However, the tibial insert design of the current patient-specific knee prosthesis does not follow the tibial plateau curvature.


2006 ◽  
Vol 22 (4) ◽  
pp. 305-313 ◽  
Author(s):  
Takeo Nagura ◽  
Hideo Matsumoto ◽  
Yoshimori Kiriyama ◽  
Ajit Chaudhari ◽  
Thomas P. Andriacchi

The aim of the study was to estimate the tibiofemoral joint force in deep flexion to consider how the mechanical load affects the knee. We hypothesize that the joint force should not become sufficiently large to damage the joint under normal contact area, but should become deleterious to the joint under the limited contact area. Sixteen healthy knees were analyzed using a motion capture system, a force plate, a surface electromyography, and a knee model, and then tibiofemoral joint contact forces were calculated. Also, a contact stress simulation using the contact areas from the literature was performed. The peak joint contact forces (M±SD) were 4566 ± 1932 N at 140 degrees in rising from full squat and 4479 ± 1478 N at 90 degrees in rising from kneeling. Under normal contact area, the tibiofemoral contact stresses in deep flexion were less than 5 MPa and did not exceed the stress to damage the cartilage. The contact stress simulation suggests that knee prosthesis having the contact area smaller than 200 mm2may be problematic since the contact stress in deep flexion would become larger than 21 MPa, and it would lead damage or wear of the polyethylene.


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