KUKU

KU ScholarWorks

  • myKU
  • Email
  • Enroll & Pay
  • KU Directory
    • Login
    View Item 
    •   KU ScholarWorks
    • Dissertations and Theses
    • Theses
    • View Item
    •   KU ScholarWorks
    • Dissertations and Theses
    • Theses
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Anatomic Variation of the Knee Extensor Mechanism: The Effect on Tibiofemoral Joint Load and Joint Kinematics

    Thumbnail
    View/Open
    Riggert_ku_0099M_15474_DATA_1.pdf (3.776Mb)
    Issue Date
    2017-08-31
    Author
    Riggert, Nicholas
    Publisher
    University of Kansas
    Format
    86 pages
    Type
    Thesis
    Degree Level
    M.S.
    Discipline
    Bioengineering
    Rights
    Copyright held by the author.
    Metadata
    Show full item record
    Abstract
    Abstract Background: Variation to extensor mechanism features of patella thickness, patella height, and tuberosity AP (anterior-posterior) and SI (superior-inferior) position will effect knee kinematics and tibiofemoral (TF) joint loads. The variations primarily relate to alterations of the patellar ligament angle, relative to the long axis of the tibia. There are two objectives in this study, first, determine the desired setting of each feature within the analog configuration of the Kansas Knee Simulator (KKS) to better match measured in-vitro TF-AP loads. Second, to describe the correlations between the features, quadriceps load, TF kinematics and patellofemoral (PF) kinematics Methods: To determine the desired analog configuration in the KKS, a custom instrumented tibia tray (ITT) was assembled with total knee replacement components from DePuy Synthes (Attune Primary, Size 8). The ITT measures TF joint load while simulating a dynamic walk and squat motion in the KKS. A design of experiments (DOE) was established, using the Taguchi analysis method to minimize the calculated RMS error. Each feature was varied between three levels. All experiments were conducted in a random order in three separate trials. To determine kinematic correlations between features, a different simulated walk was applied to 18 fresh frozen cadaver knees (age 59.3 ± 13.2 years old, 25.1 ± 6.4 BMI) in the KKS. Data points were taken at every 5% of the cycle for quadriceps load, and TF and PF kinematics. The data were normalized to create an 18x151 correlation matrix for principle component (PC) analysis. Subsequent PCs were included for analysis until 80% total explained variation was reached. The resulting coefficient matrix (“loadings”) was used to show the correlation between variables for each PC. Results: Signal-to-noise ratios for each feature were used to set the desired analog configuration at a patella thickness of 28.3-mm, patella height of 44.4-mm, and a tuberosity position of 29.3-mm (SI) and 40.6-mm (AP). The desired configuration reduced the calculated RMS error from 71.95-lbs in the original configuration to 4.76-lbs. The most sensitive factors affecting TF-AP load are patella thickness and tuberosity position. The PC analysis found the first 5 PCs accounted for over 80% of the variation. PC-1 explained 33.4% of the total variation and shows a correlation of patella height to changes in a majority of kinematic descriptions included in this analysis. The remaining PCs showed correlations to specific kinematics and anatomic measures at decreasing amounts of explained variation. Conclusion: Patella thickness and tuberosity position, and the corresponding patella ligament angle, have the greatest effect on TF-AP load. These measures are associated with minimal explained variation and correlated to limited kinematic changes. Patella height had minimal effect on TF-AP load, but is associated with the majority of explained variation and correlated to changes in quadriceps load, tibia rotation, and patella spin, tilt, and ML translation. TF-AP load is most affected by variation in patella thickness and tuberosity position, and kinematic changes are most affected by variation in patella height. Understanding the effects of variation in the three extensor mechanism features will guide more informed conclusions in future research, prosthetic and surgical tool development, and decisions regarding medical intervention.
    URI
    http://hdl.handle.net/1808/25925
    Collections
    • Engineering Dissertations and Theses [1055]
    • Theses [3901]

    Items in KU ScholarWorks are protected by copyright, with all rights reserved, unless otherwise indicated.


    We want to hear from you! Please share your stories about how Open Access to this item benefits YOU.


    Contact KU ScholarWorks
    785-864-8983
    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    785-864-8983

    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    Image Credits
     

     

    Browse

    All of KU ScholarWorksCommunities & CollectionsThis Collection

    My Account

    Login

    Statistics

    View Usage Statistics

    Contact KU ScholarWorks
    785-864-8983
    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    785-864-8983

    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    Image Credits
     

     

    The University of Kansas
      Contact KU ScholarWorks
    Lawrence, KS | Maps
     
    • Academics
    • Admission
    • Alumni
    • Athletics
    • Campuses
    • Giving
    • Jobs

    The University of Kansas prohibits discrimination on the basis of race, color, ethnicity, religion, sex, national origin, age, ancestry, disability, status as a veteran, sexual orientation, marital status, parental status, gender identity, gender expression and genetic information in the University’s programs and activities. The following person has been designated to handle inquiries regarding the non-discrimination policies: Director of the Office of Institutional Opportunity and Access, IOA@ku.edu, 1246 W. Campus Road, Room 153A, Lawrence, KS, 66045, (785)864-6414, 711 TTY.

     Contact KU
    Lawrence, KS | Maps