Clinical Lower Limb Alignment in Medial Knee Osteoarthritis and the role of Laterally Wedged Orthoses

Abstract

Osteoarthritis (OA) often affects the medial tibiofemoral joint (TFJt) of the knee. Foot posture could explain inconclusive study findings evaluating laterally wedged orthoses (LWOs) as an intervention. The overall aim of this PhD is to establish clinical lower limb alignment profiles in OA and non-OA participants. The thesis will then evaluate the mediating effect, if any, of foot posture on dynamic in-shoe loading patterns in OA gait and non-OA gait. The thesis further investigated the influence of LWOs on patient centred outcomes scores and in-shoe patterns in OA patients in a randomised controlled trial (RCT). The most prevalent foot posture in the non-OA group and the OA group was mildly pronated using the Foot Posture Index (FPI-6) (p>0.01). There were significant differences in the static and dynamic TFJt angles (p<0.01). In-shoe plantar pressure measurements also demonstrated a greater loading area and peak magnitude of loading in an OA pronated foot compared to a non-OA pronated foot (p<0.05). A 12 week RCT compared the effects of LWOs and a neutral orthotic on patient-centred outcome scores and in-plantar pressure measurements. While there were no significant differences between the groups for pain, symptoms, activities of daily living, recreational ability and quality of life (QoL) (p>0.05), there were significant differences within the groups over time (p<0.01). In the OA control group, there was an increase in peak pressure (p=0.03) in the lateral rearfoot compared with the treatment group. This suggests the LWOs may have had an offloading effect. Foot posture did not have an effect on patient centred outcome scores parameters (p>0.05), however, there was a footwear effect on in-shoe plantar pressure measurements (p<0.01). Clinical measures of foot posture did have a mediating effect on in-shoe plantar pressure outcomes in OA and healthy gait but not on patient outcome scores. The role of footwear alongside LWOs was a significant insight as it has rarely been considered. Their combined effect could help to reduce pain, manage symptoms and improve QoL in OA patients.