The role of functional foot orthoses on calcaneal and tibial kinematics : a clinical perspective using 3-dimensional motion analysis

In-shoe orthoses are used in the treatment and prevention of lower limb injuries in particular patellofemoral pain associated with subtalar joint pronation. The aim of this thesis was to investigate the precise effects of in-shoe orthotic on the Calcaneus and Tibia. Two-dimension frontal plane kinematics may be used in the clinical setting to determine static and dynamic kinematics of the lower limb and foot. The findings of this thesis highlight several limitations of their use. The adoption of 3-D high speed analyses into the clinical setting is proposed. An investigation into dynamic 3-D trials using a rigid model of a tibia resulted in an overall length measurement accuracy of 0.5mm. This was considered clinically significant and reached statistical significance (p<0.001). Five healthy volunteers were selected for a repeated measures analysis. Transverse tibial rotation was analysed as subjects walked on a treadmill at a fixed speed of 1.1 m/s (4.1 km/h). Investigations were conducted at the same time each day across a three week period. Statistical analysis was performed using an intraclass correlation coefficient. The findings demonstrated moderate to high repeatability (ICCr=0.786).This was considered clinically acceptable. Thirty two competitive runners with a past history of unilateral knee pain volunteered for participation in the study on rearfoot and tibial kinematics. All subjects had in-shoe orthoses of the same type and design and reported no pain at the time the study was conducted. A unique cluster mount and tibial wand was designed and used to determine 3-D calcaneal frontal plane movement through modified footwear and transverse tibial motion. Statistical analysis was performed using Microsoft Excel™ and SPSS 13.5™. Calcaneal eversion at heel strike was increased in shod and orthoses (p<0.05). Internal tibial rotation was reduced in orthoses with custom orthotics reaching statistical significance over shod and generic orthotics trials (p<0.05). Analysis of subject variability resulted in increased calcaneal eversion and internal tibial rotation variability increases of 0.8° to 12.0° (p<0.05) at heel strike and midstance. The range of variability similarly increased between 1.0° at heel strike and 3.0° at midstance (p<0.05). The unique findings of this thesis provide clinical based evidence the functional role of foot orthoses in the management of lower limb pathomechanics may be more than previously thought. In-shoe orthoses exert angular kinematic changes in rearfoot and tibial motions and increases in rearfoot and tibial variability in walking.