Timed Stair Ascent (TSA), Lower Extremity Functional Scale
(LEFS), and Activity- Speci
fic Balance Confidence (ABC) Scale.
Scripted instructions were read to each SM for respective tasks.
The 6MWT is frequently used to assess aerobic
fitness,
endurance, and mobility.
11,12
Age-based normative times have
been established in military and civilian personnel,
11,13,14
and
the 6MWT is suggested as a reproducible measure of exercise
tolerance.
15,16
The SMs were instructed to walk as far as pos-
sible in 6 minutes and the total distance walked was recorded.
The SAI assesses functional ability while ascending or
descending one
flight of stairs. Scores range from 0 to 13 based
on ability to perform the task, how the task is executed, and
level of upper extremity support required.
17
Zero signi
fies
inability to negotiate stairs and 13 represents reciprocal gait
without use of a rail or assistive device. Ascent and descent
are scored independently.
For the TSA, SMs were timed while safely ascending
11 stairs. They were required to touch each stair on ascent
and completed 5 trials (with 1-minute rest in between). Time
began when their foot hit the
first stair and stopped when both
feet were on the top platform. Timed stair climbing is often
used as an objective measure of mobility and power, and has
established test
–retest reliability in older adults.
18,19
SMs were
instructed to touch every step to the top of the staircase as
quickly and as safely possible, turn around, and come back to
the bottom. It was documented if the SMs needed to use the
handrail, if needed, for safety. Every subject performed 5 trials
with 1 minute of rest between trials.
The LEFS questionnaire, completed by SMs, involves a
list of 20 activities that are rated on a scale from 0 (unable
or dif
ficult to perform) to 4 (able to perform without diffi-
culty). This tool has been used in various patient populations
to assess and track a person
’s ability to perform everyday
tasks. It is often used as a baseline measure, and through-
out the course of rehabilitation, to monitor progress and set
functional goals.
20
The ABC Scale is a self-report instrument used to evalu-
ate an individual
’s balance confidence and fear of falling
during functional activities.
21
It has demonstrated reliability
and validity in older adults who have sustained an amputa-
tion; however, the psychometric properties of this instrument
have not been speci
fically examined in younger adults fol-
lowing a traumatic amputation.
22
The ABC Scale has 16 items
representing balance/functional activities, and the participant
is asked to rate his/her con
fidence level in performing these
tasks (using a scale of 0
–100, with 0 = no confidence and
100 = complete con
fidence). The response to the following
pertinent question is reported:
“Do you or would you have
any dif
ficulty at all with going up or down 10 steps (about
one
flight of stairs)?”
Normality was determined using the Shapiro
–Wilk test
with a threshold value of p
≤ 0.05. Between-session differ-
ences were evaluated using paired t tests for normally dis-
tributed data (participant height, participant weight, 6MWT,
stair ascent time, and ABC score) whereas nonparametric
data were assessed using the Wilcoxon signed-rank test. Sig-
ni
ficance was again set at p ≤ 0.05. Effect sizes (Cohen’s d)
were determined for performance measures.
RESULTS
The SMs had an average (SD) age of 25.5 (3.4) and time
from injury of 352.4 (119.6) days at enrollment. It is impor-
tant to note that the time to independent ambulation, as
de
fined in the inclusion criteria of the study, was variable for
the subject group (range = 203
–580 days). The follow-up
FIGURE 1.
Results of the 6MWT show participants were able to cover a
signi
ficantly greater distance (m) at the follow-up visit (*p = 0.005).
FIGURE 2.
Average method of stair ascent (left) and descent (right) as
measured by SAI (Buell et al
29
) improved (increased) at follow-up visits for
the six participants that completed stair functionality testing.
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57
Outcomes of Service Members With Bilateral TF/KD Amputations
evaluation was completed on average 135 (47
–300) days after
initial evaluation. Although leg length can be readily modi
fied
for individuals with bilateral amputation, height did not
signi
ficantly differ between sessions ( p = 0.386); all but one
participant was either the same height or slightly shorter
at the
final visit. Weight did not change between sessions
( p = 0.452) with all but two SMs staying within 2.0 kg of
initial weight. All SMs completed LEFS and 6MWT testing.
Only 6 of 10 SM completed stair testing at both initial and
final visits, and only those with initial and follow-up stair
function data were included.
At the follow-up visit, all SMs were able to cover signi
fi-
cantly more distance within 6 minutes ( p = 0.005, d = 0.76).
On average, SMs gained 135.3 (70.1) m between sessions
(Fig. 1). The mean distance traveled in 6MWT at the
final
collection of this study was 389 (94) m.
Average SAI ascent scores were 5.3 (4.0) initially and
7.0 (4.4) at follow-up, but the difference was not signi
ficant
( p = 0.102, d = 0.40; Fig. 2). The average SAI descent scores
did not increase signi
ficantly between sessions (3.5 [3.4]–
3.8 [3.7]; p = 0.66, d = 0.09; Fig. 2).
There was no signi
ficant change ( p = 0.247, d = −0.49;
Fig. 3) in mean time to ascend stairs between initial and
final visits.
The initial self-reported value of LEFS scores was
reported as 3.0 (0.9) with a
final value of 3.5 (0.5), which
was not statistically signi
ficant ( p = 0.059, d = 0.66).
Mean balance con
fidence during stair ascent increased
from 69.2% (19.7) on a 0 to 100% scale at the
first visit to
76.8% (21.1) at the
final visit; the difference was not statis-
tically signi
ficant ( p = 0.34, d = 0.36; Fig. 4).
DISCUSSION
Longitudinal outcomes data are lacking for individuals who
have experienced BTFA. Functional outcomes data can play
a valuable role in clinical treatment planning as data can be
used to objectively track recovery over time and identify
factors that may in
fluence the rehabilitation process. Many
SMs with BTFAs are able to return to functional community
ambulation but require more time than uninjured individuals
to complete gait-related tasks. Therefore, the data presented
provide insight into the functional abilities of SMs with
BTFA at the point of independent ambulation and progress
during the
first year of rehabilitation.
As a group, initially these SMs with BTFA demonstrated
large de
ficits in the 6MWT compared to uninjured controls.
However, mobility did improve over the course of rehabilita-
tion as seen in the increase in distance traveled during the
6MWT. In fact, the average distance traveled increased from
327.8 (75.0) to 388.5 (93.8), which was much closer to the
452 (141) m previously reported for those with unilateral
TFA.
23
Remaining differences could be because our SMs
were tested earlier in the rehabilitation process, relative to
those with unilateral TFA who were on average 2.3 years
’
postamputation.
23
The average distance of SMs with BTFA
at follow-up was still much less than the distance traveled
by uninjured controls: 761 (87) m.
23
These results provide a
6MWT milestone for those with BTFA.
Many aspects of mobility did not improve beyond the
point of independent ambulation. Although subjective ABC
score signi
ficantly improved, objective improvement was not
observed in the SAI during ascent or decent, the LEFS, or
the TSA. Ascending stairs requires greater strength and
motion than level-ground walking,
24
and not surprisingly,
several SMs were unable to complete the task at initial
assessment. The lack of statistically signi
ficant changes in
the SAI score, the ABC score, and the LEFS score shows
the dif
ficulty of completing important functional tasks in
FIGURE 3.
Although completion times varied between participants, the
average time to ascend 11 stairs improved (decreased) by an average of 6.4
(11.9) seconds at the follow-up visit.
FIGURE 4.
Average stair ambulation con
fidence score, as recorded by
ABC evaluation, was signi
ficantly greater at the final visit (*p = 0.034).
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Outcomes of Service Members With Bilateral TF/KD Amputations