Orthotic Devices for Post-Polio Syndrome: An Orthotist’s Perspective

Alexander M. Miller, CPO, Evergreen Prosthetics & Orthotics, Denver, Colorado

The field of orthotics is continually evolving to meet the needs of individuals experiencing upper and lower extremity weakness or deformities. In the post-polio syndrome (PPS) community, lower extremity weakness, often affecting one or both legs, is commonly addressed with orthotic devices such as Ankle-Foot Orthoses (AFOs) or Knee-Ankle-Foot Orthoses (KAFOs).

Fifty years ago, these devices looked very different. With advancements in materials like carbon fiber and the advent of 3D printing, the range of bracing options for those with PPS-related weakness has expanded significantly. Prefabricated carbon fiber AFOs have become increasingly popular in recent years and are frequently prescribed by doctors as the primary treatment for conditions such as foot drop, foot slap or knee buckling.

Carbon Fiber AFOs

The carbon fiber AFO is a prefabricated or custom-fabricated device designed to provide dynamic correction at the ankle or knee, primarily in the sagittal plane. There are two common styles of carbon fiber AFOs: the Posterior Cuff (Posterior Leaf Spring) and the Anterior Shell (Ground Reaction). Many orthotic and prosthetic clinics have these readily available in stock or as trial kits.

The Posterior Cuff style focuses solely on correcting ankle movement in the sagittal plane (dorsiflexion and plantarflexion). It is often prescribed for individuals with foot drop or foot slap, conditions stemming from weakness in the tibialis anterior or posterior calf muscles. The Anterior Shell style provides greater stability compared to the Posterior Cuff, as it delivers a ground reaction force during the stance phase of gait. This creates an extension moment at the knee, preventing knee buckling and enhancing stability at both the knee and ankle.

The extended footplate also addresses dorsiflexion and plantarflexion weak-nesses. Both styles are typically made of carbon fiber, making them lightweight and easy to fit into shoes.

Manufacturers such as Ottobock, Thuasne and Thrive Orthopedics produce these devices, which can be explored further on their websites.

For cases requiring more control over the ankle-foot complex, custom carbon fiber AFOs are an excellent option. When ankle weakness extends beyond the tibialis anterior, more robust bracing is required.

A popular solution is the PDE strut-style AFO, which combines the dynamic properties of carbon fiber with the control and adjustability of thermoplastic. Fabtech Systems, for example, offers a kit that incorporates an interchangeable carbon fiber strut to provide dynamic assistance for dorsiflexion and plantarflexion.

3D-Printed AFOs and KAFOs

Another exciting innovation in the field is the use of 3D printing. By employing scanning and additive manufacturing techniques, the fabrication of orthotic devices can be streamlined, reducing time and material waste.

Companies like Icarus Medical are pioneering these methods to create bracing solutions for lower limb applications at the knee and ankle.

One of their notable innovations is the Hercules KAFO, a 3D-printed, lightweight knee orthosis attached to either a carbon fiber AFO, their proprietary 3D-printed AFO, or other custom AFOs. This brace is particularly unique because it can be detached below the knee, allowing the user to wear either the knee brace or the AFO portion independently. It is also one of the lightest KAFOs available on the market.

Microprocessor-Controlled KAFOs

In the United States, two primary options for microprocessor-controlled KAFOs are available: the Ottobock C-Brace and the Blatchford Tectus Brace. Both are custom-made using carbon fiber and other advanced materials. The key feature of these devices is a microprocessor unit that controls the resistance of the knee joints through hydraulic or spring-assisted mechanisms, enabling a more natural and secure gait.

These devices require training and trial periods to ensure that the user can effectively operate the brace. While they are among the most expensive orthotic devices, they are sometimes covered by insurance.

Final Thoughts

As an orthotist, I frequently encounter patients who have been using the same device for most of their lives, making change difficult. However, with the variety of modern bracing options now available, there are many choices that can be discussed with your doctor or orthotic specialist.

I encourage orthotic users with PPS to regularly consult with their orthotist to maintain their current device or explore potential upgrades. The difference can truly be life changing.