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Lower extremity injuries
Published in Youlian Hong, Roger Bartlett, Routledge Handbook of Biomechanics and Human Movement Science, 2008
William C. Whiting, Ronald F. Zernicke
Quadriceps tendon and patellar tendon ruptures: Extreme acute forces or chronic trauma to a weakened KEM may lead to tendon rupture. Quadriceps tendon rupture usually happens to people over 40 years old as a focal lesion at the osteotendinous junction at the superior pole of the patella. In contrast, patellar tendon ruptures tend to happen before the age of 40 years, and most often rupture at the inferior patellar pole.
Development and evaluation of a new procedure for subject-specific tensioning of finite element knee ligaments
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Bhrigu K. Lahkar, Pierre-Yves Rohan, Helene Pillet, Patricia Thoreux, Wafa Skalli
Attachment sites for the cruciate and collateral ligaments were based on the already identified locations (Rochcongar et al. 2016). For other ligaments and tendons (femoro-patellar ligament, patellar tendon, quadriceps tendon, posterior capsule), general anatomical sites were used based on a priori knowledge of an anatomist. Each cruciate ligament was represented by 2 bundles (Blankevoort and Huiskes 1991) along with MCL (deep and superficial) (Smith et al. 2016). Posterior capsule and femoropatellar ligaments were each represented by 8 bundles (4 bundles in the medial and lateral side each), while quadriceps and the patellar tendon as 4 bundles each (Germain et al. 2016) and LCL as one (Meister et al. 2000). All ligaments and tendons were represented as point-to-point, tension-only cable elements as their contribution in tension are much higher than that in compression (Baldwin et al. 2009; Harris et al. 2016). Three frictionless surface-to-surface contact pairs were considered: tibia-femur cartilage (medial and lateral) and femur-patella cartilage with augmented penalty solution algorithm.
Open-sourced semi-automatic program for ultrasound assessments of femoral trochlea cartilage health
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
McKenzie S. White, Riann M. Palmieri-Smith, Lindsey K. Lepley
All images were processed and analyzed in a semi-automatic, custom-built program developed in MATLAB (version 2021a MathWorks, Natick, MA). In detail, images of the uninjured knee (n = 18) were filtered with a fourth-order Butterworth filter and enhanced with a contrast-limited adaptative histogram equalization method (Zuiderveld 1993–2020) to better define the echogenic borders of the articular cartilage. The interfaces between the quadriceps tendon and the articular cartilage of the patellofemoral joint can be defined by 3 hyperechoic borders: a faint hyperechoic line of demarcation at the near-side of the quadriceps tendon-cartilage interface, a clear hyperechoic line of demarcation at the far-side of the quadriceps tendon-cartilage interface, and a clear hyperechoic line of demarcation at the near-side of the cartilage-bone interface. The near and far quadriceps tendon-cartilage interface and the near cartilage-bone interface were manually traced on the image (Figure 1B). The intercondylar notch was automatically detected as the deepest point of the far quadriceps tendon-cartilage interface. As needed, the intercondylar notch was adjusted to ensure the anatomical position was correctly identified. The whole-intercondylar ROI was centered at the point of the intercondylar notch and defined as the middle 25% of the manually drawn ROI for assessments of a) reliability, b) full thickness, c) refraction corrections, and d) sub region analyses. To ensure the assessments of the medial and lateral regions were comparable for reliability purposes in cases where the intercondylar notch was not centered in the image, the ROIs were constrained to 10 mm.
Occupant–vehicle dynamics and the role of the internal model
Published in Vehicle System Dynamics, 2018
The simultaneous activation of alpha- and gamma-motoneurons is known as coactivation. In the absence of disturbances and uncertainties the expected muscle length will match exactly the actual muscle length and stretch reflex action will not occur. However if disturbances cause the actual muscle length to change unexpectedly, the change in length is sensed by the muscle spindles which activate the muscle, via the alpha-motoneurons in the spinal cord, to compensate the disturbances and minimise the change in length. Stretch reflex action can be observed easily by tapping the quadriceps tendon just below the kneecap.