A six degrees of freedom arthrometer for examination of knee joint laxity

Student thesis: Master thesis (including HD thesis)

  • Mathias Niels Blicher Bech
  • Morten Hauge Nielsen
  • Philip Valentin Bak
4. semester, Sports Technology (cand.tech.), Master (Master Programme)
Introduction: Knee joint laxity may cause knee instability and is associated with the risk of knee injuries.
Injuries increase the probability to develop subsequent conditions such as osteoarthritis. The current methods
of measurements have several limitations, including non-quantiable measures and one-dimensionality. The
aim of the current thesis was to develop an arthrometer with six degrees-of-freedom to assist examination
of static knee joint laxity.
Methods: The arthrometer consists of a top and bottom platform linked with six linear actuators to provide
the required mobility. Simulations of the length and size were conducted in the AnyBody Modelling System
while the durability of the top platform was assessed through a nite element analysis in SolidWorks. A
simplied motion capture test was performed to verify the range of motion (ROM) of the arthrometer
compared to the highest laxity values found in the current literature. The ROM was tested by manually
positioning the arthrometers in the end positions during three dierent examinations i.e. anterior-posterior
(AP) translation, varus-valgus (VV) rotation, and internal-external (IE) rotation.
Results: The maximum AP translation, VV rotation, and IE rotation were found to be 383.41 mm, 18.97 degrees,
and 90.17 degrees, respectively.
Discussion: The arthrometer presented has the potential to stress individual ligaments in the knee joint,
hence assist the examination of static knee joint laxity. Furthermore, it provides the opportunity to combine
movements and forces in multiple planes.
Publication date7 Jun 2017
Number of pages75
ID: 259299306