Mechanisms to absorb load in amputee running

Abstract

Background: We aimed to determine if a shock absorbing pylon (SAP) influenced the ground reaction force characteristics and the shock absorbing mechanisms compared to a rigid pylon (Rigid) during the loading phase in running. Objectives: To determine if the SAP influences the mechanisms of loading compared to the Rigid condition. Study Design: A convenience sample of transtibial amputees participated in a laboratory-based study. The prosthetic set-up was randomly altered fd\sdsd. Methods: Five recreationally active male transtibial amputees age: 18-50 years; mean mass: 86.7 ± 17.5 kg; height: 1.77 ± 0.07 m) volunteered from a population-based sample. They completed a within-participant-designed study assessing a SAP and a Rigid condition during running. Kinematic and kinetic data were collected during two sessions following a one-week customization period. Results: Loading rate, peak vertical and horizontal ground reaction forces and the time to each measure along with knee and hip angular displacement, absorbing powers and work done between the SAP and Rigid conditions were not systematically affected by the prosthetic condition. Conclusions: The effect of the SAP was minimal and inconsistent in the loading phase, with only some amputees presenting higher and others with lower values for the tested variables. Clinical relevanceThe inclusion of a prosthetic shock absorber in the form of a SAP did not systematically alter the kinetic characteristics or shock absorbing mechanisms of the residual joints. It appears that the prescription of a SAP is not justified for these recreationally active amputees.

A systematic review of shock-attenuating componentry for lower limb amputees

“…Although the details of these studies were unclear in a number of cases, many were performed within a laboratory or rehabilitation facility, [48][49][50][51] with the assistance of a certified prosthetist to undertake the fitting and alignment of prostheses. [48][49][50][52][53][54][55] Despite observations of minor trends, the vast majority of studies were suggestive that SAPs show no strong effect for a difference in the ability to attenuate shock as compared to rigid pylons among transtibial amputees while undertaking different modes of activity, including walking, running and stepping down from an elevated platform. [47][48][49][50][53][54][55] Some studies did report isolated but significant differences in group variables, including a reduction in knee flexion upon initial contact when fitted with a SAP and while walking at a controlled speed, 48 as well as differences in select variables among individual participants.…”

“…[48][49][50][52][53][54][55] Despite observations of minor trends, the vast majority of studies were suggestive that SAPs show no strong effect for a difference in the ability to attenuate shock as compared to rigid pylons among transtibial amputees while undertaking different modes of activity, including walking, running and stepping down from an elevated platform. [47][48][49][50][53][54][55] Some studies did report isolated but significant differences in group variables, including a reduction in knee flexion upon initial contact when fitted with a SAP and while walking at a controlled speed, 48 as well as differences in select variables among individual participants. 51,55 These findings, however, were not consistent with the overall trend of the included studies.…”

“…[47][48][49][50][53][54][55] Some studies did report isolated but significant differences in group variables, including a reduction in knee flexion upon initial contact when fitted with a SAP and while walking at a controlled speed, 48 as well as differences in select variables among individual participants. 51,55 These findings, however, were not consistent with the overall trend of the included studies.…”

Running at submaximal speeds, the role of the intact and prosthetic limbs for trans-tibial amputees

“…Heel marker displacement data in the forward direction were used to calculate step length, which in turn was used to calculate running speed (step length/step time). Stance was defined by a vertical GRF threshold of 10 N [12] and divided into braking and propulsion when horizontal GRF equalled zero. Peak vertical (pVF), braking (pBF) and propulsive (pPF) GRF (N.kg -1 ) were extracted and horizontal braking (BI), propulsion (PI) and vertical impulses (VI) calculated by trapezoidal-rule integration.…”

Impact testing of the residual limb: System response to changes in prosthetic stiffness

“…It follows that stiffness properties of the prosthetic limb may also serve many of these same functions. However, contrary to expectations, previous gait studies have not demonstrated that "shock absorbing" prosthetic components have an appreciable effect on ground reaction force (GRF) profiles [3][4][5][6][7][8][9][10][11].…”