Balance control on a moving platform in unilateral lower limb amputees

Objective To study balance control on a moving platform in lower limb amputees. Design Observational cohort study. Participants Unilateral transfemoral and transtibial amputees and able-bodied control subjects. Interventions Balance control on a platform that moved in the anteroposterior direction was tested with eyes open, blindfolded and while performing a dual task. Main outcome measures Weight bearing symmetry, anteroposterior ground reaction force and centre of pressure shift. Results Compared to able-bodied subjects, in amputees the anteroposterior ground reaction force was larger in the prosthetic and non-affected limb, and the centre of pressure displacement was increased in the non-affected limb and decreased in the prosthetic limb. In amputees body weight was loaded more on the non-affected limb. Blindfolding or adding a dual task did not influence the outcome measures importantly. Conclusion The results of this study indicate that experienced unilateral amputees with a high activity level compensate for the loss of ankle strategy by increasing movements and loading in the non-affected limb. The ability to cope with balance perturbations is limited in the prosthetic limb. To enable amputees to manage all possible balance disturbances in real life in a safe manner, we recommend to improve muscle strength and control in the non-affected limb and to train complex balance tasks in challenging environments during rehabilitation.