An investigation of the clinical relationship between foot posture and patellofemoral joint alignment

It has been suggested that abnormal foot posture is related to patellofemoral joint pain. An understanding of the relationship hinges on assessment of the relationship between the two, but whilst satisfactory (reliable and valid) clinical methods of foot posture exist, there is no consensus on the optimal technique for assessing patellofemoral joint alignment. Therefore, a series of studies were performed to examine standardisation, reliability, validity and functional significance of patellofemoral joint alignment measures (Q, modified A, tibiofemoral joint and tubercle sulcus angles). Intraclass correlation coefficients of all measures was fair-to-excellent (standard error of measurement <2o), whilst each measure showed significant differences (p<0.001) in selected foot positions and postures (i.e. 10o abduction, maximally pronated). A cross-sectional study then investigated normal values for these measures in 335 asymptomatic individuals. The Foot Posture Index© was used to categorise participants into pronated (n=110), neutral (n=111) and supinated (n=114) groups. All patellofemoral joint measures differed significantly between pronated and supinated foot postures, with values tending to increase with pronation. This data was used to categorise 60 asyrmptomatic individuals into three patellofemoral joint alignment groups (high, central and low, n=20 per group), and a group of patellofemoral joint pain patients was also included. Rearfoot and midfoot loading characteristics were obtained using the EMED® -m system. Comparisons between groups showed significant differences, with high and patellofemoral joint pain groups demonstrating slower and reduced loading at the rear and midfoot compared to central and low groups (p<0.001). Whilst further inquiry is required this data suggests that foot posture, functional foot loading characteristics and patellofemoral joint alignment are related. Differences in loading characteristics suggest a mechanism by which patellofemoral joint alignment and foot posture may be related to pathology. This provides a rationale for clinical interventions aimed at modifying foot and/or patellofemoral joint alignment