Introduction Ankle supports are routinely issued to patients following ankle injury and surgery [Lin et al. 2010]. Patients may be advised to use Tubigrip (elasticated tubular bandage), a stirrup brace or a type of removable walker boot (Figure 1). The primary differences in support design are the extent and direction of mechanical limitation to ankle joint motion. One of the main aims of the initial phase of rehabilitation after injury or surgery is to optimise the recovery of a normalised walking gait pattern.
Aim To determine the effects of ankle supports on gait symmetry in healthy adults.
Methods Participants were 18 healthy adult volunteers. This study was a randomised three-treatment, three-period, cross-over design. The order of ankle supports tested was balanced using Latin squares. Outcomes: 1) step length and single limb support time symmetry indices (SI). SI are an expression of the relationship between the injured and uninjured limb [Hodt-Billington et al. 2011]. The SI have a minimum of 0 (perfect symmetry) and 0.1 is equivalent to 10% asymmetry, 0.5 is 50% asymmetry and so on. 2) step width (cm). These temporo-spatial gait parameters were measured on the GAITRite® electronic walkway system (CIR Symptoms, Havertown, PA, USA). The concurrent validity of GAITRite® has been established against the VICON® system [Webster et al. 2005]. Participants walked across the electronic walkway six times in each support (twice at slow, preferred and fast walking speeds). Gait outcomes were normalised for walking velocity by use of multilevel modelling.
Results Participants were on average 42 (SD 13) years old and 88% were female. The walker boot resulted in gait abnormalities compared with Tubigrip. There was greater asymmetry in step length in the walker boot when compared to Tubigrip by a 10% margin (95% CI 9 to 12%, p < .001, Figure 2). Single limb support time was also more asymmetric in the walker boot than in Tubigrip, however this difference was smaller (5%, 95% CI 3 to 7%, p < 0.001). Step width was wider in the walker than in Tubigrip by a substantial 4.1 cm margin (95% CI 3.7–4.5 cm, p < 0.001). The only difference between the stirrup brace and Tubigrip was a wider step width but this was a small difference of 0.9 cm (95% CI 0.5–1.3 cm, p < 0.001).
Discussion Walker boots induce step length and single limb support time asymmetry and widen step width compared with Tubigrip in non-pathological gait. There are no important differences in gait in an ankle stirrup brace compared with Tubigrip. Further research is required to directly compare the effects of these ankle supports in clinical populations to further inform clinical decision making.
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