Effects of Temperature Control Liner Materials on Long-Term Outcomes of Prothesis Use

Background: The proposed work will generate evidence-based practice guidance for temperature
control liner technologies and allow providers to optimize care to Service members and
Veterans with limb loss. Sizeable numbers of Service members and Veterans live with limb
loss, mostly due to traumatic musculoskeletal injury. Addressing the resulting functional
deficit with prostheses increases the risk for secondary conditions such as pressure sores,
impaired blood perfusion, and injuries from accidental falls. Any of those occurrences can
render the prosthesis temporarily useless, making it challenging for users to engage in many
activities of daily life, including work, exercise, and social participation. Many of the
described issues originate at the interface between residual limb and prosthetic socket,
where the objectives of sufficient weight distribution and suspension are conflicting with
the necessity to facilitate heat exchange and limit contact pressure and friction.

Recently, prosthesis liners that contain phase-change material have become commercially
available, holding the promise that the micro climate at the interface between the residual
limb skin and the prosthetic socket can be regulated to reduce the users' tendency to sweat.
Preliminary studies on these liners indicate that the socket temperatures inside the socket
stayed lower and rose slower than in conventional liners. However, the clinical relevance of
those findings remains unclear. While (perceived) socket comfort is certainly an important
criterion in prosthesis fitting, it may be claimed that only tangible functional benefits are
of concern.

Objective/Hypothesis: The purpose of this study is to investigate whether longer (6+ months)
periods of use of phase-change material based temperature control liners have clinically
meaningful effects.

It is hypothesized that use of phase-change material infused liners will improve prosthesis
utilization (measured in days of prostheses use per time), physical performance (measured by
2-minute walk test), and self-reported prosthesis related quality of life (assessed by
questionnaire). The research follows the rationale that lower and steadier skin temperatures
should result in reduced sweat, friction, skin damage, and prosthesis abandonment. This would
encourage users to wear their prosthesis for longer periods of time and for an expanded array
of purposes, thus increasing their ability to ambulate and to engage in a greater variety of
activities.

Specific Aims:

1. To compare phase-change material liners to conventional liners with regard to activity
and participation

2. To quantify the effect of phase-change material liners on prosthesis related quality of
life and physical performance over time

3. To investigate the relationship between perceived benefits of phase-change material
liners and patient-centric outcomes

Study Design: The proposed study will utilize a double-blind longitudinal cross-over research
design. A sample of trans-tibial prosthesis users will be wearing their regular gel or
silicone liners for six months and phase-change material liners for another six months in a
randomized sequence. Their prostheses will be equipped with activity monitors, and
participants will be asked to maintain a record of days when they could not wear their
prosthesis due to any perceived issues with their residual limb or socket fit. In 1.5-month
intervals, subjects' activity, physical performance, and overall prosthesis assessment will
be recorded using standardized methods.

Inclusion Criteria:

- use of a prosthesis with liner suspension,

- at least one year of prosthesis use,

- a well-fitting socket,

- a matured residual limb (stable limb volume) that has not required socket
modifications in the previous year,

- the ability to walk with the prosthesis outdoors without notable limitations (K-Level
3),

- stable weight,

- absence of acute medical conditions that would temporarily affect the ability to use
prostheses.

Exclusion Criteria:

- use of a non-standard liner size,

- current use of a PCM liner as the regular suspension system,

- known allergies against liner materials,

- any inability to understand the protocol and to comply with the associated tasks, such
as maintaining a log of days when the prosthesis could not be used.

- anticipated provision of a new prosthesis or extended (longer than one month) absences
from the region during the study period