Plastics Used in Artificial Legs

Several plastics are used in the creation of prosthetic legs.

An important component in the creation of prosthetic limbs is the materials used to manufacture them. Certain materials can positively or negatively impact the strength, agility and comfort of artificial legs. Plastic materials are used in various parts of a prosthetic leg.

Plastic Polymer Laminates

Plastic polymer laminates are used to fabricate prosthetic sockets. The plastic begins as a liquid and is subsequently mixed with a catalyst. The new mixture is applied to a model of the limb, which then saturates reinforcement textiles on the mold. The plastic polymer then creates a laminated layer that is both lightweight and strong. According to Amputee Coalition, "common types of plastic polymer laminates used in prosthetics are acrylic, epoxy and polyester."

Reinforcement Textiles

Reinforcement textiles are the fabrics and plastic materials used to add strength to a prosthetic leg or limb. Plastics such as nylon, carbon fiber, Dacron or Kevlar are commonly used as reinforcement textiles. When creating a prosthetic socket, several reinforcement materials may be used at the same time. This process ensures the socket has the flexibility of Kevlar and fiberglass with the strength of carbon fiber.

Thermoplastics

Thermoplastics are used as the structural components of prosthetic limbs. Available in a variety of sizes and colors, the two most common thermoplastics are polypropylene and polyethylene. Polypropylene is a rigid plastic that is often utilized as the supporting structure in prosthetic legs. Low density polyethylene is a soft plastic that is used in most flexible areas of the prosthetic leg. In addition to polypropylene and polyethylene, there are several blended plastics that provide multiple benefits to artificial legs. A co-polymer (polypropylene and ethylene), for example, is a plastic material that is more flexible and crack resistant than polypropylene.

Cosmetic Foams

Prosthetic legs are often covered with a foam material in order to match the look of the other leg. Composed of polyurethane and polyethylene, the foams vary from very soft (above the knee) to firm (below the knee). The foam material is available in oversized "blanks" that are custom shaped to match the person's size and physical frame. Additionally, the plastic can be color-matched to the amputee's skin tone, and may include other fine details such as the appearance of hair.

References

• Amputee Coalition: Materials Used in Prosthetics Part I; Jack E. Uellendahl, CPO; September 1998
• Amputee Coalition: Materials Used in Prosthetics Part II; Jack E. Uellendahl, CPO; September 1998
• Disabled World: Prostheses, Prosthetics and Artificial Limbs