Keep moving forward: a new energy returning prosthetic device with low installation height after Syme or Pirogoff amputation.

Background: The incidence of foot amputations increased in the Netherlands to 3.3/100,000 people up to 1994. Despite these numbers, only a few basic prosthetic and orthotic devices are available, and all lack functionality to restore ankle and foot mobility.

Objectives: The aim of this explorative study was to design and test a unique prosthesis for Syme or Pirogoff amputees with the necessary low installation height but restoring ankle and foot mobility.

Study Design: A case study was performed.

Methods: The new prosthesis was designed and numerically analyzed on aspects concerning strength and deformation. A prototype was tested in a case study to assess the biomechanical behavior of the new foot. As a reference, six Syme/Pirogoff amputees were measured. Additionally, all volunteers filled out a questionnaire to evaluate their prosthetic feet.

Results: The self-selected and maximum walking speed of the case subject at 0° and 5° slopes was higher using the new foot (0.36 m/s and 0.53 m/s, respectively) comparing to the Low Rider (Otto Bock HealthCare) (0.31 m/s and 0.31 m/s, respectively). Using the new foot, a more symmetrical walking pattern was achieved.

Conclusion: The case study shows that this new prosthetic foot could be an improvement compared to existing prosthetic feet.

Clinical Relevance: Foot amputees with low available installation height still experience daily the inconvenience of missing ankle and foot mobility. Their low velocity and cosmetically poor walking pattern influence on their sound leg and overall walking functionality. A more functional prosthesis would have a great impact on their daily activities.