Page 95 - REV T-I JOURNAL INTERIOR ISSUU 18 2-3

TRANSFEMORAL SOCKET IMPACT ON GAIT & FALLS 171

prosthetic use was 14.4 years (3 to 40) (Table 1). MDC has not been established in the TFA population.
Subjects’ mean ABC score was 77.2 (±16.8; 35.6 In this study, the mean difference was a 23.5 point
to 96.9) for the IRC and 90.7 (±5.7; 77.5 to 98.7) for improvement (p = 0.02) for the users of the HiFi
the HiFi. The difference was statistically significant (90.7) versus the IRC (77.2) sockets. An ABC score of
(p = 0.02) (Figure 2). The aggregated mean distance 68 is associated with falling post-stroke (18). In this
walked on the 2MWT was 91.8 m (±22.0, 58.3 to study, both groups were above this fall risk threshold.
124.7) on the IRC compared to 110.4 m (±28.7; 64.7 Our hypothesis that the improved prosthetic control
to 171.1) for the HiFi socket (p = 0.0001) (Figure 3). would yield increased ABC scores was supported.
Further, the HiFi group reported ABC scores higher
DISCUSSION than other patient populations, such as those suffering
We hypothesized that the less cumbersome walls from Parkinson’s or stroke and the elderly. Conversely,
and subischial trimlines afforded by the HiFi, com- when using the IRC socket, ABC scores tended to be
pared with SOC interfaces, would offer improved similar to scores in these populations (18-20).
freedom of movement. This freedom of movement The socket has been identified as the most import-
may enable improved walking capacity and improved ant prosthetic element; however, TFA prosthetic
prosthetic control as evidenced by improved ABC socket fit is problematic using SOC IRC prosthetic
scores. The minimum detectable change (MDC) for socket interface. A subischial compression and tissue
the 2MWT has been previously reported as 34.3 m release design such as the HiFi may improve comfort
(15). This threshold was not reached in this study. and increase user control by utilizing femoral control.
However, in three previous studies comparing lower This could lead to improved walking capacity and
extremity amputees using the 2MWT, distances confidence, which could reduce falls. Discomfort
walked reached up to 140 m (14). The majority of and lack of control have been associated with poor
amputees tested in these studies had transtibial level socket fit. This reduces function of the prosthesis
amputation. In this study, only transfemoral level for the amputee. Although common, the SOC IRC
amputees were evaluated. TFA patients using the interface design has potential limitations, such as
HiFi socket achieved distances similar to transtibial limiting range of motion, decreasing comfort, and
amputees in previous studies. Patients’ walking capac- interfering with urogenital function, and potential
ity was significantly improved with use of the HiFi fitting complications affecting overall quality of life
interface relative to the SOC alternative, supporting (21,22). Benefits of a novel TFA interface such as
this portion of the hypothesis. Reduced gait speed, an the HiFi could potentially address areas identified as
indicator of walking capacity, has been associated with problematic and lead to alternative interface designs
falling (16). This is of particular relevance in the TFA that improve quality of life among TFA patients.
population. Maintaining optimal walking capacity, A common conclusion among the aforementioned
including normal or near normal gait speed, should studies is that falls in amputees can be mitigated with
be of primary concern in prosthetic design. Prosthetic training programs and alternative interventions. To
elements, including the socket, must be considered begin a strength and walking program, the use of an
as potential factors in assisting a patient to achieve effective prosthesis is imperative. Collectively, prior
variable cadence and faster gait speeds. In this study, authors also agreed that ongoing research is required
the HiFi interface design was determined to have a to develop appropriate intervention strategies to ame-
significant effect on improving walking capacity. liorate fall risk (6,23-25). Such interventions should
Deathe et al. assessed 17 outcome measures used consider alternative prosthetic interfaces.
in amputee clinical trials to assess mobility (17). The
ABC scale was recognized as being valid and widely Limitations
used. The MDC for the ABC has been previously A limitation of this study was the small patient
reported as 11 and 13 in studies of other pathologies. population exposed to both socket designs. Socket