Shoe Choice Can Affect Prosthetic Foot Characteristics
In a study to observe the effects of footwear on the mechanical properties of a prosthetic foot-shoe system, including commonly prescribed prosthetic feet, researchers found that shoes can alter function of the prosthetic foot-shoe system in unexpected and sometimes undesirable ways, and can often cause similar behavior across devices, despite differences in foot design.
Stiffness and energy return was measured using a hydraulic-driven materials test machine across combinations of five prosthetic feet and four common shoes as well as a barefoot condition. Heel energy return decreased by an average of 4-9 percent across feet in all shoes compared to barefoot; a cushioned trainer displayed the greatest effect. Foot designs that may improve perceived stability by providing low heel stiffness and rapid foot-flat were compromised by the addition of shoes.
Shoes altered the prostheses' mechanical characteristics in the sagittal and frontal planes, suggesting that shoe type should be controlled or reported in research that compares prostheses. The researchers suggest that understanding how different shoes could alter certain gait-related characteristics of prostheses may aid decisions about footwear made by clinicians and prosthesis users, and that prescribing clinicians should consider these effects on prosthesis performance.
The study was published online May 9 in Prosthetic and Orthotics International.