Gait stability on slopes and lateral inclines in transtibial and transfemoral amputees.

This study is part of the Dutch UDBenchmark-project, which is part of the
European EUROBENCH-framework (eurobench2020.eu).

EUROBENCH aims to create the first framework for the application of
benchmarking methodology on robotic systems. The framework, specifically
focused on bipedal robotic technologies (humanoids and exoskeletons), will
include methods and tools to measure System Ability Levels on a rigorous,
quantitative and replicable way, both during stance and during gait.

The UDBenchmark-project is a collaboration between the VU University,
Amsterdam, The Netherlands, Military Rehabilitation Center 'Aardenburg', Doorn,
The Netherlands and Heliomare, Wijk aan Zee, the Netherlands. The goals of this
project are to deliver:
(1) a minimal and flexible measurement protocol, ...
(2) data analysis software, ...
(3) a reference database ...
to assess how exoskeletons and humanoids perform while walking on slopes and
lateral inclines.

The measurements for which approval is requested can be used to assess:
- to what extent transfemoral and transtibial amputees are able to adapt to
standing and walking on slopes and laterally inclined surfaces in terms of
standing and walking stability and
- how this stability is related to different prosthetic components

Using a more extensive variant of this protocol we measured 20 healthy subject
over a range of walking speeds, slopes and lateral inclines, both with and
without an extension limiting knee brace or mobility limiting ankle brace. The
protocol of this study was evaluated and approved by the Scientific and Ethical
Review Board of the Faculty of Behavioral and Movement Sciences from the VU
University, Amsterdam, The Netherlands.

To deliver:
data to be used as part of a reference database for the EUROBENCH-framework.

To assess:
- to what extent transfemoral and transtibial amputees are able to adapt to
standing and walking on slopes and laterally inclined surfaces in terms of
standing and walking stability and
- how this stability is related to different prosthetic components

Quasi Experimental

During the experiment, subjects stand or walk on a treadmill at a pace of 0.6
(m/s) (2.16 km/h), while the slope of the treadmill increases in steps of 3
degrees from 0 to a maximum of 15 degrees in anteroposterior or lateral
direction. Transtibial amputees will undergo this protocol on a carbon fibre
prosthetic foot and a glass fiber prosthetic foot.

All combinations of these conditions and prosthetic components will be offered
as individual trials, resulting in a total of 2 (standing/walking) x 2
(slope/lateral incline) = 4 trials for transfemoral amputees and 8 trials (4
trials x 2 prosthetic feet) in transtibial amputees.
If the subjects feel or appear unable to continue standing or walking on a
given slope, the trial will be stopped.

The duration of this protocol is up to 120 minutes for transfemoral amputees
and up to 180 minutes for transtibial amputees. Since all subjects will be
recruited from the Netherlands, and measurements take place in Doorn, maximal
travel time is estimated 4 hours (2 hours from and to Groningen or Maastricht).
The tests will be performed in an unfamiliar virtual reality laboratory, that
can be somewhat intimidating to the subjects.
The amplitudes of imposed slopes could be larger than the maximal capacity of
transtibial amputees and probably is larger than the maximal capacity of
transfemoral amputees, which could result in a fall if the subject or
researcher does not decide to stop in time. To prevent negative consequences as
a result of a fall, all subjects will wear a safety harness.
The gait lab (CAREN: Computer Assisted Rehabilitation ENvironment) of the
military rehabilitation center is used on a daily basis to improve patients'
ability to walk on varying slopes as part of a multidisciplinary rehabilitation
program. These patients include transtibial and transfemoral amputees.
The military rehabilitation center has worked with this system for more than 10
years. Dr. M.R. Prins, who will be present at all the measurements, is
registered in the BIG-registry as a physiotherapist and has been working
fulltime at the VR rehabilitation department of the rehabilitation center for
10 years (and
still works there fulltime). Therefor, we estimate the chance of unforeseen
risks as 'low'.