Cath Lab Digest

Medial malleolar irritation and talonavicular irritation are some of the common issues that arise for patients wearing ankle-foot orthoses (AFOs). Accordingly, this author offers salient preventive advice and provides essential pearls for treating complications with functional and gauntlet AFOs when they occur.

   Over the past 15 years, ankle-foot orthotic (AFO) therapy has become an integral part of many podiatric practices. As with any DME item, there can be comfort, fit or function problems that emerge when patients use AFOs. It is imperative that the prescribing physician be adept at troubleshooting any situation that may occur.

   The most common AFOs currently in use include the functional AFO (Richie Brace type) and the gauntlet AFO (Arizona Brace type). Both of these AFOs are now commonly used in the podiatric profession for pathologies including adult-acquired flatfoot, ankle degenerative joint disease (DJD) and lateral ankle instability. Both types are available from many orthotic laboratories under several brand names.

   With this in mind, let us take a closer look at the most common complaints that patients have with AFOs.

   For functional AFOs, the common complaints are medial malleolar irritation and talonavicular (TN) irritation. For gauntlet AFOs, the most common complaints involve irritation at the collars at the proximal and distal aspects of the AFO.

A Guide To Troubleshooting Gauntlet AFOs

   Since a gauntlet AFO holds the foot in a more stable position, there tend to be fewer problems with irritation as it is less likely for pronatory forces to increase pressure on the medial malleoli and the navicular. It is fortunate that we see fewer issues with this AFO as it is much more difficult — and in most cases impossible — for practitioners to modify this AFO themselves. The brace manufacturer must make the modifications.

   The most common areas that tend to cause irritation are the collars at the proximal and distal aspects of the AFO. The most common complaint is that the collars are simply too tight. This is frequently due to edema that increases leg and foot circumference.

   To prevent this problem, try to cast patients toward the end of the day when edema is likely to be greatest. If these areas do irritate the patient, return the AFO to the lab for stretching.

   Correct casting technique is critical to achieve optimum clinical outcomes. Casting for gauntlet AFOs includes the use of a semi-weightbearing cast with a slight heel raise, maintaining the foot at 90 degrees to the leg.

Emphasizing Proper Patient Selection And Appropriate Casting Of Functional AFOs

   When prescribing functional AFOs, practitioners must take care to select appropriate patients and cast patients properly. Functional AFOs are appropriate for patients with the following conditions: severe flatfoot, arthritis of the ankle/foot, posterior tibial tendon dysfunction, ankle sprains/instability, dropfoot and/or tendonitis.

Keep in mind that functional AFOs are not appropriate for:

   • patients with equinus as their primary deformity in Achilles tendonitis;
   • patients with posterior group spasticity; or
   • patients with severe subtalar joint subluxation (i.e., late Stage 3 or Stage 4).

   Additionally, patients heavier than 250 lbs. or taller than 6’2” should not receive functional AFOs.

   However, those who are not candidates for functional AFOs may be candidates for other varieties of AFOs, including the aforementioned gauntlet AFOs.

   Correct casting for functional AFOs includes maintaining the foot at 90 degrees to the leg with the subtalar joint in neutral position, the midtarsal joint locked and the first ray plantar flexed.