How tibiofemoral alignment and contact locations affect predictions of medial and lateral tibiofemoral contact forces. Issue 4 (26th February 2015)

• Record Type: Journal Article
• Authors: Lerner, Zachary F.; DeMers, Matthew S.; Delp, Scott L.; Browning, Raymond C.
• Is Part Of: Journal of biomechanics. Volume 48:Issue 4(2015)
• Page Start: 644
• Page End: 650
• Publication Date: 2015-02-26
• Subjects: Animal mechanics -- Periodicals; Biomechanics -- Periodicals; Biomechanics -- Periodicals; Mécanique animale -- Périodiques; Biomécanique -- Périodiques; Electronic journals; 571.4305
• DOI: 10.1016/j.jbiomech.2014.12.049
• Languages: English
• ISSNs: 0021-9290

Abstract

<abstract abstract-type="author" id="ab0005"> <title id="sect0005">Abstract</title> <sec> <p id="sp0040">Understanding degeneration of biological and prosthetic knee joints requires knowledge of the <italic>in-vivo</italic> loading environment during activities of daily living. Musculoskeletal models can estimate medial/lateral tibiofemoral compartment contact forces, yet anthropometric differences between individuals make accurate predictions challenging. We developed a full-body OpenSim musculoskeletal model with a knee joint that incorporates subject-specific tibiofemoral alignment (<italic>i.e.</italic> knee varus-valgus) and geometry (<italic>i.e.</italic> contact locations). We tested the accuracy of our model and determined the importance of these subject-specific parameters by comparing estimated to measured medial and lateral contact forces during walking in an individual with an instrumented knee replacement and post-operative genu valgum (6°). The errors in the predictions of the first peak medial and lateral contact force were 12.4% and 11.9%, respectively, for a model with subject-specific tibiofemoral alignment and contact locations determined through radiographic analysis, <italic>vs.</italic> 63.1% and 42.0%, respectively, for a model with generic parameters. We found that each degree of tibiofemoral alignment deviation altered the first peak medial compartment contact force by 51N (<italic>r</italic><sup>2</sup>=0.99), while each millimeter of medial-lateral translation of the compartment contact point locations altered the first peak medial compartment contact force by 41N (<italic>r</italic><sup>2</sup>=0.99). The model, available at <ext-link ext-link-type="unknown" id="ir0005" xlink:type="simple" xlink:href="http://www.simtk.org/home/med-lat-knee/" xmlns:xlink="http://www.w3.org/1999/xlink">www.simtk.org/home/med-lat-knee/</ext-link>, enables the specification of subject-specific joint alignment and compartment contact locations to more accurately estimate medial and lateral tibiofemoral contact forces in individuals with non-neutral alignment.</p> </sec> </abstract>