Correlation of Transtibial Prosthetic Alignment Quality and Step-by-Step Variance of Gait

Abstract

Introduction The quality of lower-limb prosthetic alignment cannot easily be measured directly but may be described by its effects on gait comfort and efficiency. It is known that gait stability and step variability are correlated, as are gait stability and prosthetic alignment. This study investigated the hypothesis that prosthetic alignment and step variability are correlated. This would have the implication that step variability can be measured to assess the quality of prosthetic alignment (and possibly other relevant factors such as prosthetic fit and componentry selection). Materials and Methods Twelve experienced users of transtibial prostheses were subjected to a protocol that introduced malalignments of their prosthetic ankle plantarflexion angle in a randomized crossover design. Perceived alignment quality was recorded via a visual analog scale. Step-by-step variability in horizontal ground reaction forces and axial ankle torsion moment was measured using a prosthesis-integrated load cell and was statistically compared with the degree of misalignment by bivariate correlation analysis. Results Findings suggest that variance in axial torsion moment and step duration may be correlated to alignment quality. Conclusions Subjective patient feedback is the recommendable criterion for alignment assessment in active and experienced users of prostheses. Further research is recommended before step variance may help assess prosthetic alignment quality in patients with less experience in prosthetic use.

Evaluation of Gait Variable Change over Time as Transtibial Amputees Adapt to a New Prosthesis Foot

“…This may indicate that the perceived accommodation quality increased along time and exercise. A similar finding was reported on the effect of prosthetic alignment, which was reflected both in measureable gait variables and in users' perceptions [26].…”

A systematic review of variables used to assess clinically acceptable alignment of unilateral transtibial amputees in the literature

“…The sagittal prosthetic foot or shoe alignment was changed in six studies. 4,17,18,22,29,31 The sagittal socket alignment was changed in one study. 28 The effect of sagittal and frontal prosthetic alignment adjustments were analyzed in 12 studies.…”

“…However, step-by-step variability showed weak correlation to these variables. 4 Kobayashi et al analyzed out-of-plane and in-plane effects of improper alignment on forces and moments at base of the socket (referred as socket reaction moment) in six studies. They found that both angular and translational changes have some significant out-of-plane and in-plane effects (Table 3).…”

“…2,3 The subjective perception of the amputee and practitioner is the most frequent criterion to uphold acceptable alignment assessment in clinical situations. 2,4 Although the sagittal socket alignment could affect socket reaction moment in both of sagittal and frontal planes, the amputee's perception from prosthetic alignment is less reliable in this plane. [5][6][7] Although in clinically acceptable alignment prosthetic foot is aligned toward an invariant roll-over shape, it is unclear that the shape would match to that of a healthy physiologic system.…”

Development and preliminary evaluation of a new anatomically based prosthetic alignment method for below-knee prosthesis

“…The subjective verification of an experienced prosthetist regarding lack of gait deviation, along with subjective feedback of an active and experienced prosthetic user is the clinical gold standard for acceptable alignment assessment (D. A. Boone et al, 2012;Fiedler & Johnson, 2017). The results of proposed method revealed no report of gait deviation and the quality of prosthetic alignment was evaluated highly favorably by the patient.…”