The relationship between limb length discrepancy and Foot Posture Index (FPI).

This study aims to evaluate the effects of an Limb Length Discrepancy on foot posture as measured by the Foot Posture Index (FPI). To measure a participant’s limb length discrepancy, a tape measure method (TMM) will be used. This method involves measuring the distance from the centre of the anterior-superior iliac spine (ASIS) to the centre of medial malleolus of the participant by use of a ruled tape. This is done with the patient’s leg externally rotated so that the lateral border of the foot lies as close to the horizontal as is comfortable. The patient will be measured in supine and sitting position in order to standardise the method. Measurement from the ASIS is a semi-intrusive measurement, requiring participants to lift their shirt so that the ASIS may be palpated; however this is a routine measure which is widely used in clinical practice. When performed by trained professionals, measurement by the TMM should cause minimal patient alarm or discomfort. The FPI is measured with the subject standing. An FPI is performed by measuring six scoring criteria and giving a score of -2 to +2 on a 5 item scale (where positive scores represent more pronated characteristics).The six clinical criteria used in scoring an FPI are: talar head palpation, supra and infra lateral malleolar curvature, calcaneal frontal plane position, talonavicular joint prominence, congruence of the medial longitudinal arch, and abduction/adduction of the forefoot compared to the rearfoot. The six scores are summed, with high positive values indicating a significantly pronated foot; high negative a supinated one and values close to zero showing a foot near neutral position. The measurements are estimted to take 15 minutes . Participants are each examined on one occasion only.