Do predictive relationships exist between postural control and falls efficacy in unilateral transtibial prosthesis users?

Objective To assess whether variables from a postural control test relate to and predict falls efficacy in prosthesis users. Design Twelve-month within and between subjects repeated measures design. Participants performed the Limits of Stability (LOS) test protocol at study baseline and at 6-month follow-up. Participants also completed the Falls Efficacy Scale-International (FES-I) questionnaire, reflecting the fear of falling, and reported the number of falls monthly between study baseline and 6-month follow-up, and additionally at 9- and 12-month follow-ups. Setting University biomechanics laboratories. Participants A group of active unilateral transtibial prosthesis users of primarily traumatic etiology (PROS) (n=12) with at least one year of prosthetic experience and age and gender matched control participants (CON) (n=12). Interventions Not applicable. Main Outcome Measure(s) Postural control variables derived from centre of pressure data obtained during the LOS test, which was performed on and reported by the Neurocom Pro Balance Master, namely; reaction time (RT), movement velocity (MVL), endpoint (EPE) and maximum (MXE) excursion and directional control (DCL). Number of falls and total FES-I scores. Results During the study period, the PROS group had higher FES-I scores (U = 33.5, p =0.02), but experienced a similar number of falls, compared to the CON group. Increased FES-I score were associated with decreased EPE (R=-0.73, p=0.02), MXE (R=-0.83, p<0.01) and MVL (R=-0.7, p=0.03) in the PROS group, and DCL (R=-0.82, p<0.01) in the CON group, all in the backwards direction. Conclusions Study baseline measures of postural control, in the backwards direction only, are related to and potentially predictive of subsequent 6-month FES-I scores in relatively mobile and experienced prosthesis users