Temporal characteristics of foot rollover of amputee walking gait when using an Energy Storage and Return prosthesis.

Background: Energy Storage and Return (ESAR) prosthetic feet provide improved walking when compared with previous designs. However, it may not mimic the unimpaired smooth and progressive movement of the foot on the floor (foot rollover).

Objective: To characterize the temporal foot rollover of participants with unilateral transtibial amputation using an ESAR prosthetic foot.

Study design: Cross-sectional.

Methods: Plantar pressure data were collected from 11 participants with unilateral transtibial amputation using ESAR prostheses (2 females, mean age 37 ± 10 years, activity levels K2-K4) and 9 unimpaired participants (3 females, mean age 33 ± 10 years). The Initial Contact, Final Contact, and Total Contact times of 7 areas of the feet (unimpaired, intact, and prosthetic feet) were studied together with the duration of the Heel Rocker, Ankle Rocker, and Forefoot Rocker. Results were compared using a mixed analysis of the variance test.

Results: Statistical analysis revealed an interaction (P < 0.05) between foot and areas. The contact times were different (P < 0.05) between unimpaired and prosthetic feet for most foot areas. Furthermore, the prosthetic foot showed the longest duration of Heel Rocker (21.1 ± 8.5% of stance phase vs. 17.7 ± 10.2% for the intact foot and 15.7 ± 8.8% for the unimpaired feet, P < 0.05) and the shortest duration of Ankle Rocker (43.8 ± 18.1% vs. 47.2 ± 16.9% for the intact foot and 50.0 ± 13.4% for the unimpaired feet, P < 0.05).

Conclusions: Results suggest that the ESAR foot does not mimic the unimpaired foot rollover, especially in the contact pattern and the heel and ankle rockers. This might have an impact on efficiency and stability of gait.