Moisture Management Liner Effectiveness Study

The comfort and fit of the residual limb within a prosthetic socket are of primary concern for many amputees. The residual limb is typically covered by non-breathable and non- thermally conductive materials that can create a warm and ultimately moist environment. These layers consist of a prosthetic liner that rolls onto the limb and traps heat and occasional extra prosthetic socks. Studies found increases in socket temperature after the prosthesis was donned. Temperatures were found to remain elevated long after activity cessation and even a rest period of double the duration of the preceding activity period is insufficient to return the limb to its initial temperature. A small amount of activity can cause the socket temperature to elevate and remain at an uncomfortable level for an extended period of time, which can lead to decreased wear times. In summary, an uncomfortable socket/residual limb interface decreases prosthesis use among amputees who want to remain active in their lives.

To address this, the investigators have developed a silicone liner approach to remove sweat from the skin and out of the socket and to passively conduct heat from the skin using thermally conductive elastomers. This liner has been developed to work alongside a thermo-electric cooling (TEC)-based module called the Intrasocket Cooling Element (ICE) developed in a parallel project by Vivonics, Inc. and Liberating Technologies, Inc. The ICE device can be embedded into the prosthesis in order to cool the residual limb. A technology that can provide thermal control while retaining adequate suspension, weight, and other prosthetic characteristics would benefit many prosthesis wearers.

This study will focus on investigating the efficacy of this novel moisture and thermal management (experimental) liner.

The rationale for this study is to determine how well the new technology can regulate the residual limb temperature, reduce the moisture generation, and remove excess moisture in a controlled laboratory environment.

The objective of this study is to measure the effects experimental techniques of moisture and thermal management has on moisture and temperature in the socket. Moisture and thermal management of the residual limb inside the prosthetic socket could result in greater comfort while wearing the prosthesis, and ultimately could result in greater function and better quality of life (QoL). Other measures that may be collected are exploratory.

A repeated measures study will be conducted to analyze the temperature and moisture generation of the residual limb with and without the experimental liner and active cooling system within a standard prosthetic socket.

Both able-bodied research subjects, and lower limb amputee research subjects who use transfemoral or transtibial prostheses will be recruited for testing. Liners for able-bodies subjects will have the distal end removed to allow for donning. All subjects will visit Liberating Technologies, Inc. to be consented and to complete study testing.

A maximum of 10 able-bodied and 20 lower-limb amputee subjects will be recruited for this study. This is increased from a target 12 subjects to account for any drop-outs, etc.

Inclusion criteria

• Lower limb amputee
• Be willing and able to complete the tasks outlined
• Are at least 6 months on a definitive prosthesis
• Fits within an experimental liner
• Can understand English in order to be properly consented and provide their feedback to the study personnel

Exclusion criteria

• The risks to pregnant women and fetuses are unknown and therefore pregnant women should not participate in the study
• Other unforeseen disqualifying criteria (such as specific cognitive issues, etc.)