Application of fetal planta pedis shape in prenatal diagnosis of clubfoot

Objective: To observe the value of fetal planta pedis shape in prenatal diagnosis of clubfoot. Methods: Totally 42 feet of 27 fetuses suspected with clubfoot by routine ultrasound were chosen as case group, and 207 normal feet of 129 fetuses between 18 and 39 weeks' gestation were randomly selected as control group. The length and width of the foot in both groups were measured, and then the width-to-length ratio was calculated. The fetuses were followed up after birth or termination of pregnancy, the footprints of case group were taken and the foot bimalleolar angles were measured. The foot width, foot length and the width-to-length ratios between the case group and control group were compared, correlation analysis between the ratio and foot bimalleolar angle was also made. Results: Significant differences existed in foot width, foot length and the width-to-length ratio between case group and control group (all P<0.05), and significant negative linear relationship was identified between the ratio and foot bimalleolar angle (r=-0.851, P<0.05). Conclusion: The fetal planta pedis shape can provide information for prenatal diagnosis of clubfoot. Compared with normal foot, the clubfoot is wider and shorter, a higher width-to-length ratio is associated with a smaller bimalleolar angle, indicating a more serious clubfoot.