Development of prosthetic foot with an adjustable rollover shape for low-activity amputees (K-level 1–2)

This research proposes a new prosthetic foot design with an adjustable rollover mechanism for low-activity amputees (K-levels 1–2) to improve walking symmetry and provide a more natural and comfortable walking experience. The design considers key factors such as foot length, weight, and height, with height being an essential factor affecting the rollover radius. The prosthetic foot was developed with adjustable rollover radii to accommodate different height categories. The strength and rollover radius were verified through finite element analysis with ANSYS 2021R2. Simulation results showed that the dorsiflexion angle ranged from 10.2° to 11.5°, increasing progressively from D00 to D10 and D11. A prototype was fabricated and evaluated in the single-subject pilot study to assess its effectiveness in improving gait symmetry using the symmetry index. The subject was a 62-year-old male (K-level 2) with a weight of 59 kg and a height of 159 cm. The results indicate that the prosthetic foot can adjust the rollover radius to 289, 297, and 323 mm, with the symmetry index improving as the rollover radius increases. The symmetry index of rollover radius for the prosthetic foot with rollover radius of 289, 297, and 323 mm, and SACH foot are 0.03%, −0.77%, −7.12%, and −11.62%, respectively. And the symmetry index of step time for the prosthetic foot with rollover radius of 289, 297, and 323 mm, and SACH foot are −4.14%, −11.07%, −18.19%, and −21.30%, respectively. In conclusion, an adjustable rollover prosthetic foot for low-activity amputees has developed. The single-subject pilot study showed that the symmetry index of the prosthetic foot with 289 mm rollover radius was better than the SACH foot in terms of rollover radius and step time of 99.7% and 80.5%, respectively.