Niagara Foot - The innovative, low cost, energy-return prosthetic foot
 
 
   
 

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Niagara Foot Pilot Study in Thailand
Midterm Report: October 18 2002
   K.P. Bryant and J.T. Bryant

Executive Summary

The Niagara foot was developed as part of the landmine victims relief programme of The Canadian Centre for Mine Action Technology (CCMAT) by Niagara Prosthetics and Orthotics (St. Catherines, ON) and Queen’s University (Kingston, ON) with the collaboration of Dupont Engineering Polymers (Wilmington, DE) and Recto Molded Products (Cincinnati, OH). With the assistance of the Thailand Mine Action Centre (TMAC), a study team visited Aranyaprathet Hospital from November 1, 2001 to November 10, 2001 to perform a clinical trial on 15 volunteer subjects. A follow-up protocol was developed to permit a patient review at 3 months by local prosthetists with communication of results by electronic and air mail. At 6 months, a study team from Canada visited the clinic to interview patients and to observe the foot components directly. The one-year study will be completed in a final visit to Aranyaprathet in December 2002. The results of the initial study are detailed in a separate document: Technical Report – Niagara Foot Pilot Study in Thailand. (January 2002). This report documents the results of the 3-month and 6-month follow-up studies.

The Niagara Foot is a low-cost energy-return system. The biomechanical advantages of the device compared to SACH designs were evident in initial trials and continue to improve with time. Patients are able to detect and appreciate the performance offered by this device, particularly in its ability to return energy during the gait cycle, thereby decreasing the muscular effort required for walking. These conclusions are partially borne out by objective measures of walking performance indicating a reduced cadence and increased stride length compared to the original SACH foot in patients.

The flexibility of the heel is a concern for some patients. Increased flexibility under load and during standing suggests to some a lack of stability for activities on uneven terrain. However, the gait performance results at six months suggest that patients are becoming more confident with the foot. The Niagara Foot also increases the loading to other components in the prosthetic system, sometimes causing failure. As such, its use as a retrofit device on older systems should be carefully considered.

The durability of the device is evident. In contrast to the SACH device currently used at the Aranyaprathet Clinic, there were no failures of the keel after six months in all patients, which is consistent with laboratory testing. Devices showed a limited amount of wear in contact regions and a small permanent upward deformation in the heel region. However, there were a number of failures in the cosmetic foot cover. In the next phase of the project, this will be redesigned to reduce the tendency to rip, retain water, and make it difficult to fit into athletic and dress footwear.

 

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