The influence of knee joint geometry and alignment on the tibiofemoral load distribution: A computational study

Uniform bolt load is critical to achieve leak-free service in pressure vessel gasketed joints. In a previous work, the authors presented the tetraparametric assembly method, which enabled to obtain a uniform final load distribution in a one-pass tightening sequence. The accuracy of the method was proved by finite element analysis and experimental tests. However, the tetraparametric assembly method was only developed for one-pass tightening sequences, and in some cases more than one pass can be necessary. Furthermore, the method was only validated for a particular joint geometry. In this sense, the present work generalizes the method for two-pass tightening sequences and studies the range of application.

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Dynamic Knee Joint Line Orientation Is Not Predictive of Tibio-Femoral Load Distribution During Walking

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2021.754715 ◽

2021 ◽

Vol 9 ◽

Author(s):

Adam Trepczynski ◽

Philippe Moewis ◽

Philipp Damm ◽

Pascal Schütz ◽

Jörn Dymke ◽

...

Keyword(s):

Knee Joint ◽

Strong Correlation ◽

Load Distribution ◽

Joint Line ◽

Force Distribution ◽

Ground Reaction Forces ◽

Joint Loading ◽

Internal Joint ◽

Reaction Forces ◽

Dynamic Alignment

Some approaches in total knee arthroplasty aim for an oblique joint line to achieve an even medio-lateral load distribution across the condyles during the stance phase of gait. While there is much focus on the angulation of the joint line in static frontal radiographs, precise knowledge of the associated dynamic joint line orientation and the internal joint loading is limited. The aim of this study was to analyze how static alignment in frontal radiographs relates to dynamic alignment and load distribution, based on direct measurements of the internal joint loading and kinematics. A unique and novel combination of telemetrically measured in vivo knee joint loading and simultaneous internal joint kinematics derived from mobile fluoroscopy (“CAMS-Knee dataset”) was employed to access the dynamic alignment and internal joint loading in 6 TKA patients during level walking. Static alignment was measured in standard frontal postoperative radiographs while external adduction moments were computed based on ground reaction forces. Both static and dynamic parameters were analyzed to identify correlations using linear and non-linear regression. At peak loading during gait, the joint line was tilted laterally by 4°–7° compared to the static joint line in most patients. This dynamic joint line tilt did not show a strong correlation with the medial force (R2: 0.17) or with the mediolateral force distribution (pseudo R2: 0.19). However, the external adduction moment showed a strong correlation with the medial force (R2: 0.85) and with the mediolateral force distribution (pseudo R2: 0.78). Alignment measured in static radiographs has only limited predictive power for dynamic kinematics and loading, and even the dynamic orientation of the joint line is not an important factor for the medio-lateral knee load distribution. Preventive and rehabilitative measures should focus on the external knee adduction moment based on the vertical and horizontal components of the ground reaction forces.

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An exploration of changes in plantar pressure distributions during walking with standalone and supported lateral wedge insole designs

Journal of Foot and Ankle Research ◽

10.1186/s13047-021-00493-5 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Calvin T. F. Tse ◽

Michael B. Ryan ◽

Jason Dien ◽

Alex Scott ◽

Michael A. Hunt

Keyword(s):

Knee Joint ◽

Knee Osteoarthritis ◽

Pressure Distribution ◽

Contact Area ◽

Plantar Pressure ◽

Load Distribution ◽

Plantar Pressure Distribution ◽

Arch Support ◽

Knee Joint Load ◽

Joint Load

Abstract Background Lateral wedge insoles (LWI), standalone or with medial arch support (supported-LWI), have been thoroughly investigated for their effects on modifying gait biomechanics for people with knee osteoarthritis. However, plantar pressure distribution between these insole types has not been investigated and could provide insight towards insole prescription with concomitant foot symptoms taken into consideration. Methods In a sample of healthy individuals (n = 40), in-shoe plantar pressure was measured during walking with LWI, with or without medial arch support (variable- and uniform-stiffness designs), and a flat control insole condition. Pressure data from the plantar surface of the foot were divided into seven regions: medial/lateral rearfoot, midfoot, medial/central/lateral forefoot, hallux. Plantar pressure outcomes assessed were the medial-lateral pressure index (MLPI) for the whole foot, and the peak pressure, pressure-time integral (PTI), and contact area in each plantar region. Comfort in each insole condition was rated as a change relative to the flat control insole condition. Repeated-measures analyses of variance were calculated to compare the plantar pressure outcomes between insole conditions. Results Regionally, medial rearfoot and forefoot pressure were reduced by all wedged insoles, with the variable-stiffness supported-wedge showing greater reductions than the standalone wedge. Lateral rearfoot and forefoot pressure were reduced by both supported-LWI, but unchanged by the standalone wedge. In the midfoot, the standalone wedge maintained pressure but reduced regional contact area, while both supported-LWI increased midfoot pressure and contact area. All LWI increased the MLPI, indicating a lateral shift in plantar pressure distribution throughout the weightbearing phase of gait. Comfort ratings were not significantly different between insole conditions. Conclusions Regional differences in plantar pressure may help determine an appropriate lateral wedge insole variation to avoid exacerbation of concomitant foot symptoms by minimizing pressure in symptomatic regions. Lateral shifts in plantar pressure distribution were observed in all laterally wedged conditions, including one supported-LWI that was previously shown to be biomechanically ineffective for modifying knee joint load distribution. Thus, shifts in foot centre of pressure may not be a primary mechanism by which LWI can modify knee joint load distribution for people with knee osteoarthritis.

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