4D CT based analysis of knee kinematics

Student thesis: Doctoral Thesis

Abstract

Introduction: Total Knee Arthroplasty, which is the last resort of treatment for osteoarthritis, is aimed at restoring the functional anatomy of the knee. Despite the recent improvements in surgical techniques, limited range of motion, postoperative instability and malalignment still hinder the restoration of the knee's original function. Bearing in mind that stability, range of motion and alignment are all directly correlated with the kinematics of the knee, then focus should be given to understanding the underlying knee mechanics to be able to restore the native kinematics. Contemporarily, routine clinical practice still relies on 2-dimensional standing X-rays to diagnose the underlying knee pathology, which is limited in terms of accurately assessing the essential knee kinematics.;Aims: Utilise the innovative 4D CT scanners to capture the articulation of healthy and replaced knees. Develop a bespoke proof-of-concept software which utilises the 4D CT data and extracts three principal kinematic outcome measures. Extract the kinematics of ten participants and analyse the data to address two low-powered pilot studies.;Methods: A 4D CT scanning protocol was developed to record a flexion-extension exercise dynamically. The bespoke software, developed in MATLAB, extracted the three principal kinematic outcome measures for the ten participants who were scanned. The extracted kinematic data for the control participants was analysed to identify the applicable range of motion for specific flexion-extension axes of the knee, via the determination of kinematic crosstalk. The patient data was used to analyse the mobility of fixed-bearing and mobile bearing implants.;Results: The software successfully extracted the six-degrees-of-freedom kinematics, performed a contact point analysis and identified the axial centre of rotation of both healthy and replaced knees. The control data identified the Trans Epicondylar Axis as being applicable for the Extension (-5º to 10º of flexion) and Transition (10º to 30º of flexion) phases of flexion while the Geometric Centre Axis being applicable for the Flexion phase (30º to 120º of flexion). The participant data did not identify any variation in the level of mobility between the fixed-bearing and mobile-bearing knees.;Conclusion: The feasibility of the developed kinematic analysis software was proven as a viable alternative, via its implementation on the healthy and replaced knees. The kinematic crosstalk of specific flexion-extension axes was shown to vary depending on the flexion angle. Mobile-bearing knees do not provide patients with extra mobility over their fixed bearing counterparts.
Date of Award11 Mar 2021
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsUniversity of Strathclyde
SupervisorPhil Riches (Supervisor) & Philip Rowe (Supervisor)

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