The survey and comparison of navicular drop and hallux deviation in women with different grades of radiographic knee osteoarthritis

Introduction: knee osteoarthritis (OA) is the most common joint disease that has created many limitations and disabilities for humankind. It has more prevalence and severity in women in comparison to men. Significant radiographic characteristics of knee OA in kellgren-lawrence grading scale are divided into degree 1(mild) to degree 4 (very severe). Biomechanical factors like static and dynamic alignment of lower extremity is one of the influential factors in the incidence and development of knee OA. In the literature, the effect of knee joint alignment on this disease is more investigated than other joints. Levinger et al. showed that people with medial knee OA in comparison to healthy people in foot posture index, navicular drop (ND) and foot arch have more significant scores. In Avani et al. study there was a significant difference in the scores of foot posture index and ND between patients and healthy people. The aim of this research was the survey and comparison of static alignment of lower extremity such as ND and hallux deviation (HD) in the women with knee OA from radiographic degree of 1 to 4. Methodology: the present research is descriptive cross-sectional and causal-comparative. The statistical sample includes 87 women patients with knee OA (age 55/03 ± 8/84 and BMI 30/66 ±4/45kg/m2). Number of knees with knee OA were 168 divided into 4 groups (degree 1: 46 knees, degree 2: 51 knees, degree 3: 49 knees, degree 4: 22 knees). Included criteria in the study were: having elementary knee OA, female gender, more than 40 years old and not being inflicted by other joint diseases. ND was measured by Muller3 method and HD by digital image and Autocad software. One-way ANOVA was used for the group comparison and under significant results, Tukey was applied. Significant level of the experiment was considered P≤0/05. Results: Results showed significant difference in the extent of ND between first and second group (8.26 in comparison to 6.35, p=0.03). ND was the most in group 2. It was higher in group 4 in comparison to group 3 and higher in group 3 to 1 but not significant. The mean of HD increased from group 1 to 4 but not significantly. Discussion: This is the first study concerned with investigating foot alignment index between different degrees of radiography of knee OA. In the present research, ND in lower limb with knee OA in 53/57% of feet and HD in 48/81% of the feet was placed in an abnormal domain. This study can be a turning point for more research concerning risk factors including lower limb malalignment for the incidence and development of knee osteoarthritis. Based on the findings we can conclude that ND is a dangerous factor for development of radiographic degree of knee OA and corrective exercises necessary for the recovery of structural and biomechanical status can contribute to the prevention of rapid development of the disease.