Prototype Socket With Heat Control Offers Better Comfort for Below-Knee Amputees
Reading Time: 4 minutes
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Summary:
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Iranian researchers unveil cooling prosthetic socket prototype
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It uses copper and an active cooling system to reduce heat buildup
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Study shows 5-6°C drop in socket temperature during use
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Aims to prevent skin issues and boost comfort for amputees
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For people with below-knee limb loss, heat buildup inside the prosthetic socket remains a common problem. The accumulation of heat and sweat in this enclosed space can cause discomfort, skin irritation, and infections, which can discourage prolonged use and may even lead to prosthetic abandonment. But this may soon be a thing of the past, as a study published in the Medical Journal of the Islamic Republic of Iran introduces a prosthetic socket prototype with heat-control technology.
The Problem: Heat, Sweat, and Skin Stress
Conventional prosthetic sockets are typically made from thermoplastics or carbon fiber composites due to their strength and light weight. However, these materials are poor at conducting heat. These materials are known to trap heat and hinder the body’s natural cooling, especially the evaporation of sweat, which causes the temperature inside prosthetic sockets to rise. Research indicates that even a small temperature increase of 1-2°C inside the socket can cause discomfort.
This thermal stress isn’t just an annoyance. Excess heat and moisture can lead to skin breakdown, blisters, dermatitis, and bacterial growth, affecting daily function and overall quality of life for prosthetic users. While traditional solutions, like gel liners or breathable materials, provide some relief, addressing the problem directly at its source—the prosthetic socket—is likely a more effective approach.
The New Approach: Copper and Cooling Control
Researchers from the Iran University of Medical Sciences introduced a new prosthetic socket featuring two key design advances: a heat-exchanging metal layer and an active cooling system.
Replacing traditional composites, the prototype socket is made of copper, a material with high thermal conductivity. The copper was then molded through electroforming, a process that enables precise fabrication of durable, custom-fit components. During production, a silicone mold of the residual limb was used as a template for electroforming the copper shell.
However, high thermal conductivity isn’t enough—heat must be removed from the socket. This is where the active cooling system, which incorporates a thermoelectric cooler, heat sink, and fan, plays a role. The cooling system continuously monitors skin temperature and activates cooling when predefined thresholds are exceeded. Sensors near the limb detect temperature rises and trigger the cooling system to maintain a comfortable internal climate.
Testing the New Socket
The researchers tested the socket prototype with a single congenital amputee who has used a below-knee prosthesis for 25 years. During testing, the ambient temperature was maintained at 29°C. The study participant alternated between his usual conventional socket and the new prototype, both with and without an active cooling system.
The temperature measurements recorded by the researchers from multiple thermistors revealed clear differences:
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The skin temperature of the residual limb increased sharply during activity with the traditional socket.
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The copper prototype without active cooling reduced some heat gain, resulting in lower peak temperatures than the conventional socket.
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When the cooling system was turned on, temperature rises were minimal—less than 1°C over baseline—and sometimes even slightly decreased.
Overall, the study found that maximum residual limb temperature dropped by approximately 5-6°C with active cooling compared to the conventional socket. The participant’s reported experience was equally encouraging; he reported feeling much cooler and more comfortable while wearing the prototype socket with the active cooling system.
What’s Next?
While this study looks promising, it is still in the early stages. As this study only tested the prototype socket on one participant, the researchers noted the need for larger clinical trials to assess performance across different body types, activity levels, and environments. Furthermore, questions about long-term durability and costs for widespread use have yet to be answered.
Nevertheless, the idea shows promise. By merging thermal management with user-focused design, this prototype might help overcome a key barrier to prosthetic use—heat discomfort—that affects amputees worldwide. Future developments could result in marketable prosthetic sockets that greatly enhance comfort and improve the quality of life of below-knee prosthesis users.
Related Reading:
A Primer on Breathable Prosthetic Liners
Skin Conditions After Limb Loss: What You Need to Know
Caring for Your Skin: Managing Prosthetic-Related Contact Dermatitis
Can Temperature-Regulating Liners Improve Lower-Limb Prosthesis Outcomes?
