A spatio-temporal and kinematic description of self-selected walking in adults with Achondroplasia

Abstract

Background: Achondroplasia is characterised by a shorter appendicular limb to torso ratio, compared to age matched individuals of average stature (controls). Despite the well documented shorter leg length of individuals with compared to controls, there are few complete descriptions of gait kinematics reported for the population. Aim: The aim of this study was to report the spatio-temporal and kinematic characteristics of self-selected walking (SSW) in a group with Achondroplasia (N = 10) and age matched group without Achondroplasia (controls, N = 17). Method: Whole body 3D analysis of both groups was conducted using a 14 camera VICON system. Spatiotemporal and kinematic variables were determined through a Plug-in-Gait model. SSW was obtained from an average of three trials equating to a total of ∼120 m walking. Results: The group with Achondroplasia were 23 % slower (P < 0.001), had a 29 % shorter stride length (P < 0.001) and a 13 % higher stride frequency (P < 0.001) compared to controls. There were no differences in time normalised temporal measures of left toe off (P = 0.365), right heel contact (P = 0.442) or the duration of double support (P = 0.588) between groups. A number of discrete joint kinematic differences existed between groups, resulting in the group with Achondroplasia having more 'flexed' lower limbs than controls throughout the gait cycle. Conclusion: Differences in absolute spatio-temporal variables between groups is likely due to the shorter leg length of the group with Achondroplasia, while their more flexed position of the lower limbs may facilitate toeclearance during the swing phase.

The talar morphology of a hypochondroplasic dwarf: A case study from the Italian Late Antique period

“…Similarly, individual T17 has likely exercised great loading at push-off, similar to barefoot hunter-gatherers or those wearing minimalistic soft-coverings, though such an explanation is highly improbable as the sole explanation for our finding given the low mobility of hypochondroplasic individuals (Haga, 2004;Sims et al, 2019Sims et al, , 2020. Indeed, recent kinematic studies on the gait cycle have shown that individuals with achondroplasia walk at a slower speed have shorter stride lengths and higher frequencies of strides compared with a group of healthy individuals, largely because of the shorter, disproportionate leg length of the former (Sims et al, 2019(Sims et al, , 2020. High stride frequencies in T17 may be a contributing factor to the more robust (i.e., short and broad) talar neck likely due to higher load given more impacts per given distance, though kinematic studies on hypochondroplasic individuals would be necessary to test this hypothesis.…”

“…High levels of ankle dorsiflexion and the presence of an anterolateral talar facet may be associated with the hypochondroplasic condition of T17. Greater ankle dorsiflexion may compensate for an increased foot/leg length ratio by preventing toe contact with the ground during swing phase of the gait cycle (Sims et al, 2019(Sims et al, , 2020.…”

“…The feet of individuals affected by achondroplasia and hypochondroplasia are described as “normal” or sometimes as broader and longer in relation to shorter legs (Sims et al, 2019; 2020; Slon et al, 2013; Traversari et al, 2020; Waters‐Rist & Hoogland, 2013). These genetic conditions affect endochondral bone formation, and bones characterized by the least number of growth plates (e.g., the femur and humerus both have only two growth plates) tend to be shortened.…”

“…The knee of T17 appears to exhibit a valgus posture (Figure 2). Even if the genu varum is a clinical hallmark of achondroplasia, the valgus knee has been also identified in achondroplasic individuals (Sims et al, 2020).…”

“…Therefore, increased ankle dorsiflexion in T17 could be interpreted as a consequence of the hypocondroplasic condition. Accordingly, Sims et al (2019Sims et al ( , 2020 have observed that achondroplasic individuals exhibit more flexed knee and ankle joints over the entire gait cycle, likely due to a higher foot/leg length ratio. More flexed lower limb joints (e.g., hip, knee, and ankle) may help to avoid toe contact with the ground during swing phase and thus maintain gait proficiency (Sims et al, 2019(Sims et al, , 2020.…”