When Do You Prescribe A Gauntlet AFO Versus A Hinged AFO?

Colleagues often ask me what criteria I use when recommending a custom hinged ankle-foot orthosis (AFO) versus a custom gauntlet AFO device. This is a very good question as many practitioners favor only one type of device and rarely consider both options in the treatment of complex foot and ankle pathologies.

The best rationale for comparing the differences between hinged AFO devices and gauntlet devices is using the analogy of choosing surgical options to treat hindfoot and ankle deformities. Podiatric physicians are well versed in the pros and cons of surgical procedures, but seem less aware of the implications of bracing complex foot and ankle pathologies.  For certain, most podiatric physicians do not perform the same surgical procedure for every complex foot and ankle condition they treat.

The most common condition that podiatric physicians treat with custom ankle-foot orthoses is adult-acquired flatfoot. While opinions vary regarding surgical approaches for stage 2 and stage 3 deformities, there is a general recognition that one should avoid arthrodesis procedures in favor of osteotomies and tendon transfers.¹ The rationale is that restricting range of motion with arthrodesis almost always has consequences with transfer of stress and demand on adjacent joints.

A hinged ankle-foot orthosis allows free ankle motion while a rigid gauntlet restricts and blocks almost all ankle motion. A hinged AFO controls and limits subtalar joint motion and midtarsal joint motion while the leather gauntlet closure AFO significantly limits all motion of the hindfoot and midfoot joints.^2,3

From a functional standpoint and making a surgical analogy, we can compare a hinged AFO to a subtalar arthroereisis while a gauntlet AFO can be analogous to a pantalar arthrodesis.

Flatfoot procedures that avoid arthrodesis are more favorable in the treatment of stage 1 and stage 2 adult-acquired flatfoot. When it comes to patients with adult-acquired flatfoot, one should avoid ankle arthrodesis with the exception of stage 4 deformities. From a surgical standpoint, use a pantalar arthrodesis only for stage 4 adult-acquired flatfoot and even then with considerable reservation.⁴

Yet it is interesting to see that a large number of podiatric physicians routinely prescribe rigid gauntlet AFO devices for stage 2 adult-acquired flatfoot as well as many other mild arthritic conditions of the hindfoot and ankle. While these braces effectively limit all motion of the ankle and hindfoot joints, these same prescribing physicians would never consider a pantalar arthrodesis for mild arthritis of the hindfoot and ankle. In comparison to prescribing habits for AFO therapy, most practitioners do not routinely perform the same surgical procedures for all stages of adult- acquired flatfoot.

Some may question if there are any negative effects from rigid bracing of the foot and ankle, thus restricting all essential motion. While authors have measured and reported these negative effects in large volumes in the surgical literature, other authors in the orthotics and biomechanics literature have also reported these negative effects relative to solid AFO bracing of the foot and ankle.^2,3,5 In short, if you take away motion from essential joints such as the ankle and subtalar joints, the proximal and distal joints will take additional load and potentially deteriorate.

In addition, restricting motion of the ankle joint can have negative effects on gait and balance, which is a serious concern with elderly patients.^6,7 Solid AFO devices almost eliminate the ability to drive an automobile when patients wear them on the right lower extremity. Solid AFO devices with a leather gauntlet closure significantly affect shoe fit and routinely require an increase of two full shoe sizes with extra depth volume. Hinged ankle-foot orthoses with an open posterior ankle shell design will not affect shoe fit or driving an automobile.

The essential message here is that AFO bracing of adult-acquired flatfoot as well as other complex deformities of the foot and ankle should follow the same principles as surgical intervention. In all cases, preservation of joint motion is preferable over arthrodesis in order to restore normal gait and avoid further complication.

Disclosure: I do own an AFO company, Richie Brace^®, which features a branded hinged custom ankle-foot orthosis. The company also offers two different rigid gauntlet braces that we recommend for stage 4 adult-acquired flatfoot as well as severe degenerative arthritis of the hindfoot and ankle.

References

1. Hiller L, Pinney SJ. Surgical treatment of acquired flatfoot deformity: what is the state of practice among academic foot and ankle surgeons in 2002? Foot Ankle Int. 2003; 24(9):701–705.
2. Kitaoka HB, Crevoisier XM, Harbst K, et al. The effect of custom-made braces for the ankle and hindfoot on ankle and foot kinematics and ground reaction forces. Arch Phys Med Rehabil. 2006; 87(1):130-135.
3. Pinney SJ, Lin SS. Current concept review: acquired adult flatfoot deformity. Foot Ankle Int. 2006; 27(1):66–75.
4. Lee MS, Vanore JV, Thomas JL, et al. Diagnosis and treatment of adult flatfoot. J Foot Ankle Surg. 2005; 44(2):78–113.
5. Neville C, Houck J. Choosing among 3 ankle-foot orthoses for a patient with stage II posterior tibial tendon dysfunction. J Orthop Sports Phys Ther. 2009; 39(11):816–824.
6. Radtka SA, Oliveira GB, Lindstrom KE, Borders MD. The kinematic and kinetic effects of solid, hinged, and no ankle-foot orthoses on stair locomotion in healthy adults. Gait Posture. 2005; 24(2):211-18.
7. Cattaneo D, Marazzini F, Crippa A, Cardini R. Do static or dynamic AFOs improve balance? Clin Rehabil. 2002; 16(8):894-899.