Bilateral rearfoot asymmetry and anterior knee pain syndrome.

STUDY
DESIGN: Single-session observational study.
OBJECTIVES: To examine the magnitude and extent of asymmetry between right and left rearfoot angles in individuals who are asymptomatic versus symptomatic for anterior knee pain.
BACKGROUND: Asymmetry in lower limb measures has been linked to the occurrence of knee pathologies, yet the practice of deriving unilateral rather than bilateral data and thereafter averaging the findings may play a role in obscuring the true nature of the rearfoot angle-knee pain relationship. METHODS AND MEASURES: A convenience sample of participants was recruited from the local university and business communities and a university-affiliated physiotherapy clinic. Eighty-on young adult males and females volunteered to participate in this study. Following an extensive screening process, including mandatory exclusion for a previous history of lower limb dysfunction or injury, data were collected from 75 individuals classified as asymptomatic (n = 50), unilaterally symptomatic (n = 11), or bilaterally symptomatic (n = 14) for anterior knee pain. Right and left rearfoot angles were goniometrically measured under static, weight-bearing conditions.
RESULTS: No significant differences in mean right and left rearfoot angles by group or limb were observed. However, these mean values did not always reflect the true variation of data within the sample. Fifty-six percent of the individuals studied demonstrated a minimum of 4 degrees bilateral rearfoot angle difference, while for 20% of the sample this difference exceeded 7 degrees. Only a we yet statistically significant correlation existed between right and left rearfoot angles (r = 0.31, P < 0.01).
CONCLUSIONS: Rearfoot angles in weight bearing are not bilaterally symmetric, and the magnitude and direction of the observed asymmetry does not appear to be indicative of whether an individual is asymptomatic or symptomatic for anterior knee pain.