BEGIN THE TEST WITH
THE PATIENT SITTING IN
THE CHAIR WITH HIS/HER
HIPS ALL THE WAY TO THE
BACK OF THE SEAT.
START TIMER ON THE
WORD GO. THE PATIENT
THEN WALKS 3 METERS
AND TURNS AROUND.
STOP TIMER WHEN
PATIENT SITS DOWN
Example of instructions from the patient survey for the Timed Up and Go (TUG) test. The TUG test, measures the
time it takes a person to stand up from a chair, walk three meters, return to the chair, and sit back down. TUG is a
basic gait test that captures many aspects of mobility in a single timed measure.
Deathe, A. B., and W. C. Miller. The L Test of Functional Mobility: measurement properties of a modified version of the timed “Up & Go” Test designed
for people with lower limb amputations. Phys. Therapy 85:626–635, 2005.
and could potentially benefit from the product.
That goes beyond the amputee to include the
prosthetist who fits and aligns the leg system,
the technicians who build and repair the components, community rehabilitation workers who
reach out to patients, hospital administrators
who are making purchasing decisions, family
members who may accompany the amputee to
the clinic, and everyone with a stake in the success or failure of remobilizing the amputee and
using the device.
The needs of the prosthetist are particularly
important. The prosthetists we meet are often
overburdened, with more patients needing care
than their clinics can provide. Prosthetists have
little time to experiment with new products
or processes. Ultimately, for the product to
get traction and create impact, the knee must
work within existing systems for prosthetic
fitting and have features that prosthetists are
accustomed to. To meet this need, we’ve created a knee with a standard “pyramid adapter”
connection, along with adjustable friction, thus
giving the prosthetist the ability to dynamically
align the knee.
Beyond the fitting process, the knee and
other components must reliably reach each
prosthetics clinic, no matter where the clinic is
located. Some clinics we’ve visited have waited
up to eight months to receive orders of prosthetic components. Scheduling the fitting of a
patient can become a waiting game, as clinics
wait for missing components to arrive. Some
clinics rely on donations of used knee joints from
the U.S. and other western markets. The supply
of donated parts is unreliable, erratic, and can
be costly to an organization’s limited resources,
because it requires significant effort to manage
and refurbish a wide range of inventory.
In the fall of 2013, we launched field trials to test
the latest version of the ReMotion Knee with
patients at four clinical sites in India, Indonesia,
and Guatemala. ( These trials are on-going at
press time.) Our assessment tool—the survey
that drives these trials—went through a product
design process just like the knee itself. We treat-
ed our partner clinics as the end-users of this
product, mapped process flows, and considered
their voice and needs during the survey design
process. The steps we took in designing the
survey have broad applicability in creating survey
instruments for resource-limited settings.
We began by conducting an extensive
literature review of existing surveys
evaluating prosthetic performance. We had
hoped to adopt standard metrics that would
allow us to compare the ReMotion Knee
to other prosthetic knees on the market.
We found, however, that almost all studies
of prosthetic performance took place in
high-income areas, and those surveys do not
address the needs and concerns of patients
living in our target markets—those living
on less than $4 per day. The majority of
prosthetics patients in high-income areas
were older diabetic patients, whereas our
target end-users are younger and active (the
average age of the subjects enrolled so far is
35). Also, the questions and measures were
inappropriate contextually. For example, one
question asked an amputee about the ease
of stepping up onto curbs, which doesn’t
make sense in our target regions because curb
height can be variable or, in some cases, curbs
don’t exist at all.