Effects of a range of 6 prefabricated orthotic insole designs on plantar pressure in a healthy population: A randomized, open-label crossover investigation

Background: Prefabricated orthotic insoles are widely commercially available for self-selection to treat foot and lower-body musculoskeletal pain, without requiring advice from health care professionals. Although they are generally designed to mimic traditional design features of custom-made orthotics used in clinical practice, the effects of prefabricated insoles on plantar pressure distribution are poorly understood. Objective: This investigation aimed to evaluate and directly compare the effects of a range of 6 different commercially available prefabricated orthotic insole designs on plantar pressure in healthy individuals. Methods: This was a single-center, randomized, open-label, crossover investigation. In-shoe dynamic pressure (F-scan) was investigated in 24 healthy subjects with normal foot posture, wearing standard shoes alone and in combination with 6 different orthotic insoles, consecutively, measured on a single day. The biomechanical impact of each insole was determined by the statistical significance of changes from baseline measurements (standard shoe alone). Results: Insoles with heel cups and medial arch geometries consistently increased contact area at medial arch and whole-foot regions and reduced both plantar peak pressure (PP) and pressure time integral at medial arch and heel regions. Conclusions: This investigation has aided in further understanding the mode of action of prefabricated insoles in a healthy population. The insoles in this study redistributed plantar pressure at key regions of the foot, based on design features common to prefabricated insoles. Prefabricated orthotic insoles represent an easily accessible means of reducing lower-body musculoskeletal stress for those who spend prolonged periods of time on their feet.