The Design of a Subtalar Joint Prosthesis Wear Testing Mechanism

• Author / Creator

  Jn Baptiste, Jonelle, M

• The subtalar joint forms part of the triple joint complex in the foot and is primarily responsible for inversion and eversion of the hind foot and ankle. Injury to the subtalar joint typically arises as a result of primary osteoarthritis or sequelae of injury. When non-invasive treatments are no longer a viable option for treatment, subtalar arthrodesis is performed on the joint. Arthrodesis, also known as fusion, entails the removal of existing joint tissue to fuse the mating surfaces of bones. While fusion reduces discomfort, and improves the overall function of the foot and ankle, it totally eliminates joint motion. It is widely known that total joint replacements have been successful in the hip, knee and ankle. However, there have been no publications on the wear testing of subtalar joint prostheses to date. Therefore, there is a need to test the feasibility of subtalar joint prostheses, which will maintain some degree of motion in addition to relieving discomfort. The long-term objective of this study is to develop and apply a testing protocol for wear of subtalar joint prostheses. To date, no protocols exist for wear testing of ankle joint prostheses. Therefore, the ISO standards for wear testing of total hip-joint prostheses forms the basis for developing that of the subtalar joint. The short-term goal is to design and build a wear testing simulator specifically for subtalar joint prostheses and test one pair of potential carbon fiber reinforced polyether-ether-ketone (CFR PEEK) subtalar joint prostheses for wear. While fatigue-testing machines for hip and knee implants exist, they are costly. A four-bar mechanism applies rotary displacement to replicate eversion and inversion while a fatigue tester applies cyclic loading simultaneously. This simulator is optimized to withstand the applied fatigue loading without failure after a minimum of 5 million cycles. To replicate physiological conditions, the implants are submerged in bovine serum diluted with deionized water. Joint implants are typically tested at 1 Hz. However, in the interest of time, expedited testing at 3 Hz was done in this study. This corresponds to the high loss in mass of the implants tested. As experimental studies on subtalar joint prostheses have not yet been published, the results of this procedure will allow future persons interested in continuing this research to determine how the setup can be improved and which materials will be best suited for use as subtalar joint prostheses.

• Subjects / Keywords

  • Prostheses
  • Subtalar joint
  • Wear testing

• Graduation date

  Spring 2018

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3599ZH1Q

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.