Effect of 3D printed insoles for people with flatfeet: A systematic review

This systematic review aimed to evaluate custom-made 3D printed insoles for people with flatfeet. PubMed, Embase, ISI web of knowledge, ProQuest, Scopus, and Cochrane databases, were searched from inception until January 2022. The quality assessment of included studies was performed through the Downs and Black checklist. A narrative analysis was performed since a meta-analysis could not be conducted. Ten studies including 225 subjects with flexible flatfeet were chosen for final evaluation. Although the evidence from selected literature was generally weak, using insoles with 3D printing technology may positively affect pain (comfort score) and foot function, with no significant change in vertical loading rate during walking or running. There were discrepancies among studies for plantar pressures, center of pressure trajectories, 3D ankle joint kinematics and kinetics of gait while wearing these insoles. Dose-response effects of medial posting on 3D printed insoles suggested beneficial effects on lower limb gait biomechanics in people with flatfeet. There was insufficient evidence to conclude the comparison between 3D printed insoles and other types of insoles. In conclusion, using a 3D printed insole may improve comfort score and foot function in people with flatfeet.