Ankle Foot Orthosis

Ankle Foot Orthosis
10 Apr 2017

The ankle-foot orthosis (AFO) ranks among the leading rehabilitation aids in the U.S. The majority of America’s four million stroke survivors wear some form of AFO to overcome drop foot and other biomechanical complications. Add the additional millions of children and adults challenged by cerebral palsy; multiple sclerosis; head trauma; polio; Charcot disease; ALS; fractures, injury and disease processes of the lower limb; and other central nervous system disorders, and you have a vast population of people whose quality of life can be improved by an appropriately prescribed, designed and fabricated AFO.

We now have a wealth of assembly and materials combinations at our disposal, each offering its own attributes for different rehabilitation objectives. With the technology and body of knowledge expanding at a rapid pace, it is the particular role of the board-certified orthotist to keep abreast of proven new developments.

That’s a critical point. It is sometimes tempting to choose non-traditional alternative providers for certain health services, forgoing qualifications and experience for a lower price. However, as in most things, “You get what you pay for” generally rings true in our field as well.

Orthotic Applications

AFOs are employed to control and correct biomechanical and/or neurological dysfunction, facilitate or restrict joint motion, maintain proper alignment of the lower limb, protect vulnerable structures, alleviate pain, and relieve weight-bearing. Overcoming drop foot is the most common and probably most familiar application. The orthosis supports the ankle at a 90-degree angle, and dorsiflexion assist may be incorporated to help the foot assume proper position for heel strike. Thus compensated, patients walk more efficiently, more safely and with less fatigue. In some instances, the objective is to protect body structures from further insult or injury, such as a chronically inflamed Achilles tendon. Other times, the goal may be to immobilize the ankle, such as in the presence of degenerative joint disease when the patient is either unable or unwilling to undergo arthrodesis surgery. Still another AFO objective is relief of axial loading by shifting some of the weight-bearing stresses to the orthosis. Many variables enter into AFO construction: Materials, trimlines and intimacy of fit are key assembly determinants.

Orthotic Materials

No factor has had greater impact on the progression of AFO assembly than the adaptation of sheet plastics to orthosis fabrication. Custom-fabricated plastic AFOs are considerably lighter in weight, more comfortable to wear, can easily be worn with different shoes, are more cosmetically pleasing, and most importantly, provide the substantial benefits of total contact. In recent years, plastic laminate buildups incorporating fiberglass and graphite resins have been employed to strengthen solid-ankle AFOs to achieve triplanar ankle immobilization. Previously, controlling ankle rotation with an AFO was difficult at best.

Orthotic Designs

Tone-reducing AFOs comprise an interesting subset of AFO de-sign based on considerable evidence that hypertonicity can be influenced by cutaneous stimulation and joint position. One version, the dynamic AFO (DAFO), is a thin, highly flexible orthosis featuring a custom-contoured soleplate that provides total contact support and stabilization of the dynamic arches of the foot. The DAFO is widely used in the pediatric population in conjunction with active postural control and balance-oriented therapy programs. The AFO Expert Rehabilitation professionals who prescribe AFOs to their patients do not need to try to keep up with the latest designs and fabrication techniques but rather to recognize that there is one type of practitioner who, generally speaking, knows more about AFOs than anyone else, including how to:

  • Perform a comprehensive patient orthotic evaluation.
  • Identify the most appropriate assembly for a given problem.
  • Accurately cast and modify a lower limb model.
  • Select the most advantageous materials.
  • Fabricate, then refine, the finished orthosis.
  • Measure outcome and modify the AFO as necessary to produce optimal results.

In the certified orthotist, rehabilitation decision-makers have at their disposal an AFO expert who can help them achieve optimal outcomes for their patients. Call us for details. We have offices located in Beaumont, Nederland and Jasper, Texas.


LeTourneau Prosthetics