Osteoarthritis of the knee is a highly prevalent disease, with total knee arthroplasty (TKA) a proven means of alleviating symptoms. In image-free navigation, infra-red markers are attached to bony landmarks to provide kinematic data during the TKA procedure, with the aim of improving the precision of the implant placement. In non-invasive navigation, infra-red markers are attached to the skin surface; recent evidence suggests that this can give reliable measurements of lower limb mechanical alignment. The aim of this thesis was to evaluate the use of a non-invasive navigation system in the assessment of mechanical alignment with applied coronal force through the range of flexion. A previously validated non-invasive system (Physiopilot) was tested on 23 volunteers with healthy knees. 2 users performed 2 registrations of the software workflow on each participant's right and left knees. A force was manually applied to the end-point of varus and valgus knee laxity and the measured change in mechanical alignment was recorded. Force was applied with the knee positioned in increments of flexion from 0˚-90˚. In keeping with previous studies, satisfactory values of CR (Coefficient of Repeatability) of 1.55 and 1.33 were found for intra-observer repeatability in measurement of supine Mechanical Femoro-tibial Angle (MFTA) in extension, with a good inter-observer correlation of ICC (intraclass Correlation Coefficient) 0.72. However, when flexion was introduced, intra-observer and inter-observer reliability fell outwith acceptable limits. The trial therefore did not support the Physiopilot system as a measure of MFTA when flexion is introduced. It was felt that learning-curve, soft tissue artefacts and lack of force standardisation equipment may have accounted for significant levels of error, with further studies required to address these issues.
|Date of Award||3 Aug 2016|
- University Of Strathclyde
|Supervisor||Phil Riches (Supervisor) & Philip Rowe (Supervisor)|