Researchers compared dynamic gait stability and between-limb stability symmetry, as measured by the Margin of Stability (MoS) and the Normalized Symmetry Index, for 19 people with unilateral transfemoral amputations before and one-year after osseointegration (OI), or bone-anchored limb implantation.
They found improved between-limb MoS symmetry, which, according to the related study, is likely due to subtle changes in individual limb MoS values at self-selected walking speeds resulting in an overall positive impact on fall risk through improved center of mass and prosthetic limb control.
The MoS provided a mechanical construct to assess dynamic gait stability and infer center of mass and limb control by relating the center of mass and velocity to the base of support.
The research team quantified dynamic gait stability anteriorly and laterally at foot strike and at the minimum lateral MoS value. After implantation, they observed decreased lateral MoS at foot strike for the amputated and intact limbs and increased between-limb MoS symmetry at foot strike and at minimum lateral stability.
Center of mass control using a bone-anchored limb resulted in dynamic gait stability more similar between limbs and may have reduced the adoption of functional asymmetries.
The study, “Dynamic gait stability and stability symmetry for people with transfemoral amputation: A case-series of 19 individuals with bone-anchored limbs,” was published in the Journal of Biomechanics.
