Effect of Custom Carbon Ankle-Foot Orthosis Use on Energetic Demands of Walking and Comparisons With Individuals With Amputation.

OBJECTIVE

To compare the metabolic demands of walking in individuals with lower limb injury with and without ankle-foot orthosis (AFO) use. A secondary aim was to compare these results with those from individuals with unilateral transtibial amputation (TTA) and able-bodied controls.

DESIGN

Cross-sectional study.

SETTING

Two clinical research centers.

PARTICIPANTS

Thirteen individuals (N=13) with lower limb injury who used a passive-dynamic AFO underwent metabolic analysis at 3 standardized speeds with and without their AFO. Results were compared with individuals with unilateral TTA who used a passive prosthetic foot and able-bodied controls with no musculoskeletal, neurologic, or cardiovascular deficits.

MAIN OUTCOME MEASURES: Oxygen consumption, heart rate, and rating of perceived exertion.

RESULTS

The use of the passive-dynamic AFO did not significantly change energetic demand (oxygen consumption, heart rate, perceived exertion) in participants with a lower limb [LL] injury. Heart rate (P<.037) was significantly greater than able-bodied controls, but perceived exertion was significantly lower (P≤.031). There were no significant differences between participants with an LL injury (with or without the AFO) and individuals with TTA.

CONCLUSIONS

Many individuals with LL injuries may expect to use passive-dynamic AFOs with little to no metabolic consequence. The stabilizing and assistive benefits of the AFO likely balance with its well-known range of motion limitations and power reductions. Passive-dynamic AFO use can sometimes be an alternative for individuals considering TTA. These results support that AFO users may be able to achieve similar energetic demands as those with amputation.