Traumatic unilateral transtibial amputation increases medial-lateral but not anterior-posterior postural sway during...

Despite notable advances in prosthetic technology, lower-limb prosthesis users continue to experience frequent falls. It remains unclear if and how amputation affects upright balance during quiet stance partly because confounding factors like age, sex, and amputation etiology are often unaccounted for in research studies.

Compare postural sway during quiet stance between traumatic unilateral transtibial prosthesis users (TTPU) and unimpaired age- and sex-matched controls.

Twelve TTPU and 12 age-, sex-matched controls performed three 70-second eyes-open quiet stance trials. Ground reaction forces were measured and used to calculate anterior-posterior (AP) and medial-lateral (ML) center-of-pressure mean velocity (COPmv). A paired Hotelling's multivariate T² test was used to evaluate differences in net AP and ML COPmv between groups.

A paired Hotelling's T² test revealed a statistically significant multivariate difference in COPmv between traumatic unilateral TTPUs and matched controls (T² = 3.83, F (2, 10) = 19.15, p = 0.001). Net ML COPmv (TTPU: 1.78 (0.51) mm/s; Controls: 1.21 (0.31) mm/s) was significantly higher in TTPU (t (11) = 3.79, p = 0.003, d = 1.09). Differences in AP COPmv (TTPU: 7.83 (2.57) mm/s; Controls: 6.20 (1.68) mm/s) were not statistically significant (t (11) = 1.77, p = 0.104, d = 0.51).

Traumatic unilateral TTPU may face greater challenges controlling unperturbed standing balance in the frontal versus sagittal plane. Determining whether these challenges in quiet stance increase susceptibility to perturbations or hinder balance recovery in the frontal plane is an important next step toward addressing balance deficits in TTPUs.