Creative Design of Custom Liners

Ten years ago, WillowWood introduced Alpha DESIGN® Liners to allow practitioners to specify the thickness and placement of gel within an Alpha® Liner. That initial offering of Alpha DESIGN Liners focused on amputees with uniquely-shaped limbs who could not wear off-the-shelf liners to experience the comfort of Alpha gel.

As clinicians have become more and more skilled in creating Alpha DESIGN Liners, a number of common trends have evolved:

• Suited for short residual limbs: Most prefabricated Alpha Liner profiles thin to 3 mm posteriorly to minimize bunching behind the knee and permit easier knee flexion. Amputees with short residual limbs, however, may not have the limb length allowing the knee to line up correctly with the prefabricated liner profile. As a result, the gel may be 6 mm to 9 mm thick behind the knee. With DESIGN Liners, a “standard” off-the-shelf Alpha Liner profile may be customized to line up exactly with an amputee’s anatomy and provide optimal knee flexion and comfort for those with short residual limbs.

• Stylized for Symes and Knee Disarticulations: Amputees who have Symes amputations or knee disarticulations commonly have residual limbs that are bulbous at the distal end. As a result, definitive sockets for these amputees typically have a unique shape. Alpha DESIGN Liners allow for gel to be added around the narrower parts of the residual limb and for gel to be reduced at the bulbous end (Figure 1). The result is a liner that internally provides a tailored fit with a uniform exterior shape, allowing for a more “standard” socket shape.

    Figure 1

• Leveling out uneven distal ends: A residual limb that is pointed (conical) or dramatically uneven distally can pose challenges in achieving a comfortable socket fit. By adjusting the gel thickness appropriately along the contours of the residual limb’s distal end, a liner can be created that cradles the residual limb interiorly while creating a smooth, uniformly-shaped distal end to an Alpha DESIGN Liner. From this point, the clinician can then create a more “standard- shaped” prosthetic socket.

• Perfect for PFFD patients: Clinicians who have patients with proximal femoral focal deficiency (PFFD) find that DESIGN Liners can be a great asset in achieving a good prosthetic fit that is also comfortable. Because the gel in DESIGN Liners can be as thin as 3 mm or as thick as 25 mm, gel can be placed in the contours of the deficiency to create a “standard” shape to which a socket can be applied (Figure 2). Comfort is achieved by containing and supporting the anatomy, allowing more opportunity for prosthetic success and improved quality of life through ADLs and sports.

Figure 2

This ability to create gel profiles that are very thin or very thick can provide benefits for a number of other clinical applications as well. Watch for the next post on this blog to learn more!