Average and peak contact stress distribution evaluation of total knee arthroplasties

Szivek, John A.; Anderson, P.; Benjamin, James B.

doi:10.1016/s0883-5403(96)80137-9

Cited by 100 publications

(52 citation statements)

References 9 publications

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“…Contact analysis often is used to identify activities at high risk to the implant and implant-bone interface [13,52]. As we use finite element-based contact analysis to compute knee kinematics from knee forces, in addition to knee forces and knee kinematics we also obtain contact area, contact stresses, and the distribution of local stresses and strains.…”

Section: Discussionmentioning

confidence: 99%

The 2011 ABJS Nicolas Andry Award: ‘Lab’-in-a-Knee: In Vivo Knee Forces, Kinematics, and Contact Analysis

D’Lima

Patil

Steklov

et al. 2011

Clinical Orthopaedics &Amp; Related Research

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Background Tibiofemoral forces are important in the design and clinical outcomes of TKA. We developed a tibial tray with force transducers and a telemetry system to directly measure tibiofemoral compressive forces in vivo. Knee forces and kinematics traditionally have been measured under laboratory conditions. Although this approach is useful for quantitative measurements and experimental studies, the extrapolation of results to clinical conditions may not always be valid. Questions/purposes We therefore developed wearable monitoring equipment and computer algorithms for classifying and identifying unsupervised activities outside the laboratory. Methods Tibial forces were measured for activities of daily living, athletic and recreational activities, and with orthotics and braces, during 4 years postoperatively. Additional measurements included video motion analysis, EMG, fluoroscopic kinematic analysis, and ground reaction force measurement. In vivo measurements were used to evaluate computer models of the knee. Finite element models were used for contact analysis and for computing knee kinematics from measured knee forces. A thirdgeneration system was developed for continuous monitoring of knee forces and kinematics outside the laboratory using a wearable data acquisition hardware. Results By using measured knee forces and knee flexion angle, we were able to compute femorotibial AP translation (À12 to +4 mm), mediolateral translation (À1 to 1.5 mm), axial rotation (À3°to 12°), and adduction-abduction (À1°t o +1°). The neural-network-based classification system was able to identify walking, stair-climbing, sit-to-stand, and stand-to-sit activities with 100% accuracy. Conclusions Our data may be used to improve existing in vitro models and wear simulators, and enhance prosthetic designs and biomaterials.

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Section: Discussionmentioning

confidence: 99%

The 2011 ABJS Nicolas Andry Award: ‘Lab’-in-a-Knee: In Vivo Knee Forces, Kinematics, and Contact Analysis

D’Lima

Patil

Steklov

et al. 2011

Clinical Orthopaedics &Amp; Related Research

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“…5 Polyethylene contact stresses often exceed the yield strength. [6][7][8][9] The contact area of a natural knee ranges from 765 to 1150 mm 2 , but drops to 80 to 300 mm 2 after TKA, depending on the load and design. [10][11][12] Peak contact stresses have been reported as high as 30-60 MPa.…”

mentioning

confidence: 99%

“…[10][11][12] Peak contact stresses have been reported as high as 30-60 MPa. 8,9 These studies have been either computed using mathematical models or measured in vitro with pressure sensors under estimated knee forces. Tibiofemoral forces measured in vivo would be extremely useful in evaluating these reports.…”

mentioning

confidence: 99%

In vivo contact stresses during activities of daily living after knee arthroplasty

D’Lima

Steklov

Fregly

et al. 2008

Journal Orthopaedic Research

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ABSTRACT:We implanted an electronic knee prosthesis to measure tibial forces in vivo during activities of daily living after total knee arthroplasty. We used tibial forces and knee kinematic data collected in vivo to calculate contact stresses using finite element analysis. The polyethylene insert was modeled as an elastoplastic material, and predicted contact stresses were validated using pressure sensitive sensors. Peak contact stresses generated during walking were similar but about 18% lower than those calculated for International Standards Organization (ISO)-recommended wear simulation conditions. Stair climbing generated higher contact stresses (32 MPa) than walking (26 MPa). However, both high flexion activities (lunge and kneel) generated even higher contact stresses, with the lunge activity generating the highest stresses (56 MPa). The activities that generated high contact stresses also resulted in high equivalent plastic strain. However, the lunge activity generated dramatically higher plastic equivalent strain than the other activities. In vivo measurement of kinematics, forces, and contact stresses may be used to develop more clinically relevant wear simulator protocols. Contact stresses generated during high flexion activities were substantially higher and were largely due to the reduced contact area in deep flexion rather than due to an increase in contact forces. Our results support the use of ''high flexion'' designs that improve contact conditions and preserve contact area at high flexion angles. ß

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“…Traditional designs with historical gamma in air polyethylene moved to more conforming designs, with lower stresses to reduce the incidence of delamination. [9][10][11] Such an example was the highly conforming low contact stress rotating mobile-bearing platform (DePuy Inc, Warsaw, IN). 12 With the introduction of modern stabilized polyethylene materials, the mechanical properties of which do not deteriorate with time, 13 it is possible to consider design solutions with a wider range of operating contact stresses, and still avoid delamination and fatigue wear.…”

Section: Science Of Polyethylene Wearmentioning

confidence: 99%

“…This can provide other advantages in performance. Although historically, with gamma in air sterilized polyethylene, more conforming designs were introduced to reduce the level of contact stresses and risk of delamination fatigue failure, 11 this had only limited benefit, because high stresses could still occur due to misalignment or edge loading, which resulted in failure. Currently used stabilized polyethylenes provide a much better solution to reduce the risk of delamination fatigue, because these materials can withstand higher stress levels.…”

Section: Science Of Polyethylene Wearmentioning

confidence: 99%

Wear of knee prostheses

Brockett¹,

Jennings²,

Fisher³

2012

ORR

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Average and peak contact stress distribution evaluation of total knee arthroplasties

Cited by 100 publications

References 9 publications

The 2011 ABJS Nicolas Andry Award: ‘Lab’-in-a-Knee: In Vivo Knee Forces, Kinematics, and Contact Analysis

The 2011 ABJS Nicolas Andry Award: ‘Lab’-in-a-Knee: In Vivo Knee Forces, Kinematics, and Contact Analysis

In vivo contact stresses during activities of daily living after knee arthroplasty

Wear of knee prostheses

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