Additive manufacturing of specific ankle-foot orthoses for persons after stroke: A preliminary study based on gait analysis data

The aim of present study is to investigate the feasibility of patient-specific ankle-foot orthoses fabricated using additive manufacturing (AM) techniques. Then, clinical performance of the AFOs manufactured using material PA12 was evaluated in stroke survivors based on gait analysis data. The ankle and foot were scanned by EinScan-Pro 3D scanner. The software Geomagic Studio was used for modifying the AFO model. After processing the original AFO model into the final required model, material PA12 were used to fabricate the AFOs by Multi Jet Fusion (MJF) technique. Finally, gait analysis of 12 stroke patients was conducted to compare the effects with and without AFO. It took 2 hours from processing the initial AFO model to the completion of final model, and the printing time was 8 hours. The printing thickness of the AFO was 1.2 mm. With respect to the temporal-spatial parameters, the velocity and stride length in the gait with AFO increased significantly as compared to the gait without AFO (P = 0.001, P = 0.002). The cadence increased, double limb support phase decreased, and the step length difference decreased in the gait with AFO; however, the difference was not statistically significant (P = 0.117, P = 0.075, P = 0.051). This study confirmed the feasibility of patient-specific AFO fabricated by AM techniques, and demonstrated the process of modifying AFO models successfully. The specific ankle-foot orthoses fabricated by material PA12 have a significant effect on the improvement of velocity and stride length in people with stroke.