Introduction: This study was conducted to examine the association between knee osteoarthritis and hindfoot angle, medial tibiofemoral angle, piriformis tightness and hip internal rotation. Aims: To examine the association between knee osteoarthritis and hindfoot angle, medial tibiofemoral angle, piriformis tightness and hip internal rotation. Methodology: A quantitative study with a non-experimental relational design was conducted on a total sample consist of 132 knees of 89 subjects ( 31 males and 58 females) age range (45__ampersandsignndash; 70). Result: On multiple regressions with entering model (R=.708, R2= .501 and p=.000), a good (R=.655) and significant correlation (p.000) lead to linear regression analysis between medial tibiofemoral angle and hindfoot angle. Pearson correlation between hindfoot angle and medial tibiofemoral angle was R=.655, R2 =.429, p=.001, beta= -.822. Pearson chi-square (p=.000), likelihood ratio (p=.000) and Fisher__ampersandsignrsquo;s exact test (p=.000) show that there is a significant association between piriformis tightness and OA grade, phi coefficient was .595 and Cramer__ampersandsignrsquo;s V was .343 which shows the association is strong. Conclusion: Medial compartment osteoarthritis of the knee joint is characterised by genu varum. It is often associated with hindfoot varus. Both genu varum and hindfoot varum can biomechanically be linked with the tightness of the piriformis muscle.