scholarly journals Effects of Daily Activities and Position on Kinematics and Contact Mechanics of Dual Mobility Hip Implant

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yongchang Gao ◽  
Xin Zhao ◽  
Shibin Chen ◽  
Jing Zhang ◽  
Zhenxian Chen ◽  
...  
Keyword(s):  
Contact Mechanics ◽  
Large Range ◽  
Stair Climbing ◽  
Daily Activities ◽  
Hip Implants ◽  
Potential Influence ◽  
Anteversion Angle ◽  
Dual Mobility ◽  
Dynamic Finite Element ◽  
Combined Movements

Dual mobility hip implants have been widely introduced to overcome dislocation in recent years. However, the potential influence of different gaits on kinematics and contact mechanics for dual mobility hip implants is still unclear. Furthermore, a large range of motion coupling with the implant position, especially high inclination or anteversion angle, may result in poor kinematics and contact mechanics. A previously developed dynamic finite element method was adopted in this study to examine the kinematics and corresponding stability of dual mobility hip implants under different gaits coupling with different inclinations or anteversion angles. The results showed only inner relative sliding under knee-bending for dual mobility hip implants under moderate inclination and anteversion angles, whereas an anteversion angle of 25° induced both impingement and consequent relative sliding of the outer articulation. However, the impingement (between the stem neck and the liner inner rim) indeed happened under stair-climbing and sitting-down/stand-up as well as combined movements when inclination and anteversion angles were set as 45° and 0°, respectively, and this finally led to relative sliding at the outer articulation. A high inclination angle did not worsen both the impingement and related outer sliding compared to modest inclination and anteversion angles of the liner, but a high anteversion angle prolonged the period of both the impingement and the outer relative sliding. The extreme motions and high anteversion angles are hardly inevitable, and they indeed lead to motions at both articulations for dual mobility hip implants.

Effect of inclination and anteversion angles on kinematics and contact mechanics of dual mobility hip implants

2018 ◽  
Vol 57 ◽  
pp. 48-55 ◽  
Author(s):  
Yongchang Gao ◽  
Zhenxian Chen ◽  
Zhifeng Zhang ◽  
Shibin Chen ◽  
Zhongmin Jin
Keyword(s):  
Contact Mechanics ◽  
Hip Implants ◽  
Dual Mobility

Using multi-dimensional contact mechanics experiments to measure Poisson's ratio of porous low-k films

2003 ◽  
Vol 766 ◽  
Author(s):  
B. N. Lucas ◽  
J. C. Hay ◽  
W. C. Oliver
Keyword(s):  
Integrated Circuits ◽  
Contact Mechanics ◽  
Poisson’S Ratio ◽  
Mechanical Response ◽  
Contact Stiffness ◽  
Poisson's Ratio ◽  
Elastic Behavior ◽  
Structural Effects ◽  
Potential Influence ◽  
Low K

AbstractUsing a new multi-dimensional contact mechanics system, it was recently shown that the experimentally measured tangential to normal stiffness ratio of a contact can be described as a function of the bulk Poisson's ratio of the material as predicted by Mindlin [1-3]. This system has been utilized to measure the normal and tangential elastic contact stiffness of a series of porous low-k films, with increasing starting porogen content. These results indicate a transition from a material-controlled elastic behavior to a structure-controlled elastic behavior as the porosity of the film is increased. These structural effects and their potential influence on the mechanical response to forces imposed on integrated circuits are discussed. The experimental details and apparatus are introduced and described.

Numerical predictions of hip joint and muscle forces during daily activities: A comparison of musculoskeletal models

2019 ◽  
Vol 233 (6) ◽  
pp. 636-647 ◽  
Author(s):  
Basil Mathai ◽  
Sanjay Gupta
Keyword(s):  
Hip Joint ◽  
Reaction Force ◽  
Daily Activities ◽  
Hip Implants ◽  
Muscle Forces ◽  
Joint Reaction Force ◽  
Musculoskeletal Models ◽  
Standing Up ◽  
Joint Reaction

Musculoskeletal loading plays an important role in pre-clinical evaluations of hip implants, in particular, bone ingrowth and bone remodelling. Joint force estimation using musculoskeletal models evolved as a viable alternative to in vivo measurement owing to the development of computational resources. This study investigated the efficiencies of four eminent open-source musculoskeletal models in order to determine the model that predicts the most accurate values of hip joint reaction and muscle forces during daily activities. Seven daily living activities of slow walking, normal walking, fast walking, sitting down, standing up, stair down and stair up were simulated in OpenSim using inverse dynamics method. Model predictions of joint kinematics, kinetics and muscle activation patterns were compared with published results. The estimated values of hip joint reaction force were found to corroborate well with in vivo measurements for each activity. Although the estimated values of hip joint reaction force were within a satisfactory range, overestimation of hip joint reaction force (75% BW of measured value) was observed during the late stance phase of walking cycles for all the models. In case of stair up, stair down, standing up and sitting down activities, the error in estimated values of hip joint reaction force were within ~20% BW of the measured value. Based on the results of our study, the London Lower Extremity Model predicted the most accurate value of hip joint reaction force and therefore can be used for applied musculoskeletal loading conditions for numerical investigations on hip implants.

Performance of the CYBERLEGs motorized lower limb prosthetic device during simulated daily activities

2021 ◽  
Vol 2 ◽  
Author(s):  
Jo Ghillebert ◽  
Joost Geeroms ◽  
Louis Flynn ◽  
Sander De Bock ◽  
Renée Govaerts ◽  
...  
Keyword(s):  
Lower Limb ◽  
Stride Length ◽  
Cognitive Effort ◽  
Stair Climbing ◽  
Daily Activities ◽  
Human Gait ◽  
Limb Amputation ◽  
Future Research ◽  
Experimental Session ◽  
Adaptation Period

Abstract Background The CYBERLEGs-gamma (CLs-ɣ) prosthesis has been developed to investigate the possibilities of powerful active prosthetics in restoring human gait capabilities after lower limb amputation. Objective The objective of this study was to determine the performance of the CLs-ɣ prosthesis during simulated daily activities. Methods Eight participants with a transfemoral amputation (age: 55 ± 15 years, K-level 3, registered under: NCT03376919) performed a familiarization session, an experimental session with their current prosthesis, three training sessions with the CLs-ɣ prosthesis and another experimental session with the CLs-ɣ prosthesis. Participants completed a stair-climbing-test, a timed-up-and-go-test, a sit-to stand-test, a 2-min dual-task and a 6-min treadmill walk test. Results Comparisons between the two experimental sessions showed that stride length significantly increased during walking with the CLs-ɣ prosthesis (p = .012) due to a greater step length of the amputated leg (p = .035). Although a training period with the prototype was included, preferred walking speed was significantly slower (p = .018), the metabolic cost of transport was significantly higher (p = .028) and reaction times significantly worsened (p = .012) when walking with the CLs-ɣ compared to the current prosthesis. Conclusions It can be stated that a higher physical and cognitive effort were required when wearing the CLs-ɣ prosthesis. Positive outcomes were observed regarding stride length and stair ambulation. Future prosthetics development should minimize the weight of the device and integrate customized control systems. A recommendation for future research is to include several shorter training periods or a prolonged adaptation period.

Sign in / Sign up

Export Citation Format

Share Document