title: Pilot validation study on a quasi-static weight-bearing knee rig.
abstract: This article presents a pilot study on a quasi-static knee rig designed to investigate the influence of pathologies and surgical interventions on the patellofemoral kinetics of cadaveric knees. The knee rig allows cadaveric knees to flex and extend under a simulated body weight by transmitting a force to the quadriceps tendon. During the squat simulation, the ground reaction force stays within physiological values. Before using this device to answer clinical questions, two knee specimens were tested to assess the repeatability of the rig. Four repeated flexion-extension cycles were performed under a simulated body weight of 700 N, with an isolated force on the quadriceps tendon up to 2700 N and with a ground reaction force close to 350 N. The resulting patellofemoral contact area shifted from distal to proximal during knee flexion. From 20 degrees to 60 degrees of knee flexion, the mean contact area and pressure increased from 80.2 +/- 3.3 to 349.5 +/- 10.1 mm2 and from 0.9 +/- 0.2 to 5.9 +/- 0.7 MPa, respectively. The transmitted force on the quadriceps tendon, the ground reaction force and the patellofemoral contact area and pressure were continuously measured and showed a relative variability of 1.6%, 2.4%, 2.8% and 3.2%, respectively. The presented knee rig shows a good repeatability that allows us to use this knee rig to quantify the influence of anatomical changes on the patellofemoral contact area and pressures during a squat simulation.
authors: Department of Mechanical Engineering, BioMech, University College Ghent, Ghent, Belgium. mvhaver@hotmail.com
authors: Annemieke
authors: A
authors: Van Haver
authors: Karel
authors: K
authors: De Roo
authors: Tom
authors: T
authors: Claessens
authors: Matthieu
authors: M
authors: De Beule
authors: Peter
authors: P
authors: Verdonk
authors: Patrick
authors: P
authors: De Baets
mesh_terms: D001696:Biomechanical Phenomena / Q000502:physiology; D035843:Biomedical Research / Q000295:instrumentation*; D005269:Femur / Q000502:physiology; D006801:Humans; D007717:Knee / Q000502:physiology*; D010329:Patella / Q000502:physiology; D057071:Patellofemoral Joint / Q000502:physiology*; D010865:Pilot Projects; D015203:Reproducibility of Results; D016474:Weight-Bearing / Q000502:physiology