Impact of amputation level and vaulting on loading parameters during level ground walking.

Background: Previous studies show that during level walking, the load on the contralateral side increases with more proximal amputation levels. Furthermore, a typical compensation mechanism, vaulting on the contralateral side, may also influence the load. However, no study has compared the load applied to the contralateral side across more than two different amputation levels.

Objective: The objectives of this study were to analyze the biomechanical impact of different lower limb amputation levels and vaulting on the load applied to the locomotor system.

Methodology: Gait data from 82 individuals with different amputation levels (44 transtibial (TT), 30 transfemoral (TF), and 8 hip disarticulation (HD)) were retrospectively analyzed in this study. Peak knee adduction, flexion and extension moments, vertical ground reaction force peaks, and force rates were statistically analyzed between different amputation levels and between two groups "TF with vaulting" and "TF without vaulting".

Findings: As the level of amputation increases, walking speed decreases and asymmetry of stance duration increases. TF individuals with vaulting tend to walk faster than those without vaulting. The first peak of vertical ground reaction forces, the peak knee adduction and extension moments increase, and the peak knee flexion moments decrease with higher amputation level. The higher the amputation level, the curve of the vertical ground reaction force becomes significantly steeper during the first 5% of the gait cycle (GC). The first peak of ground reaction forces, the knee flexion, extension and adduction moments tend to be higher in TF individuals with vaulting.

Conclusion: In summary, a higher lower limb amputation level can increase loading on the contralateral limb and contribute to a higher incidence of vaulting during gait. The effect of vaulting as a compensation pattern leads to an additional increase in contralateral limb loading.