There is ongoing confusion about paediatric foot posture, and a lack of clearly defined values results in overdiagnosis of ‘flatfoot’, and frequently unnecessary treatment. The main objectives of our collaboration were to: enlarge reference data for foot posture across childhood, and to clarify the influence of basic anthropometry (BMI) on paediatric foot posture. It has long been cited that heavier children have flatter feet, yet also refuted. This study both doubles the previous normative data for paediatric foot posture, and extends the age range.
Amalgamation of datasets from cross-sectional studies in Spain, UK, and Australia was undertaken.
The final dataset comprised 3217 healthy children, aged from three to 15 years. Foot posture was described by means and z-score of the foot posture index (FPI). Height and weight of each participating child was used to calculate the body mass index (BMI), and percentiles were used to categorise BMI.
A pronated foot posture (FPI ≥ +6) was found in 960 (29.8%), and a normal foot posture (FPI 0 to +6) in 1776 (55.2%) of children. The less common foot postures, highly pronated (FPI ≥ +10 ) were found in 127 (3.9%) children, and supinated foot (FPI < 0) in 354 (11.0%) children.
Approximately 20% of children were overweight/obese, but correlation between BMI and FPI was weak and inverse (r = -0.066, p< 0.01), further refuting the relationship between increased body mass and ‘flat’ or pronated feet.
Discussion and Clinical Relevance
This study confirms that the ‘flat’ or pronated foot is common in childhood, with FPI score of +4(3) the average finding across all ages. A wide normal range of foot posture across childhood is confirmed, with 68% of children having FPI range +1 to +7.
Clinicians should be aware that both highly pronated feet (FPI > +10), and supinated foot posture (FPI < 0) is unusual, and should prompt both differential diagnoses, and gait evaluation.
A foot posture versus age ‘ready reckoner’ has been produced for clinical use and parent education.