Current Concepts In Diagnosing And Treating Drop Foot

Author(s): 
Nicholas Romansky, DPM, Kelly Scollon-Grieve, MD, and James G. McGinness, CPO

   Years ago, the profession considered short leg braces, conventional or metal bracing attached to the shoes as the main solution for this gait dysfunction. A simple leg tracing, accurate measurements and a skilled orthotist are all that is necessary to construct this type of brace. Providing enough dorsiflexory assistance often required the use of a Klenzak ankle system in which dual spring mechanisms supply assistive forces that would overcome the resistance of the foot and ankle with no active dorsiflexion. One can modify all the patient’s shoes for removal of the brace, which allows easy shoe interchange.

   The advent of plastic bracing has been an especially significant addition for the treatment of drop foot. This process involves the orthotist taking a cast of the lower limb and carefully crafting a custom made orthosis. Various modifications, such as the addition of joint systems with these thermoplastic braces, can further customize the treatment of the individual patient’s condition. Tamerac joints simulate spring action and assist the foot and ankle in moving through a normal range of motion. Controlled ankle motion joints can limit joint motion to a specific degree range of motion. In treating drop foot and other mechanical problems of a weakened foot and ankle, another axiom is to brace only what the deficit demonstrates. Over-bracing, while well intended, may weaken other critically needed support systems of the ankle complex. If patients are always in the brace, then the leg muscles go unused and the muscles weaken.

   However, there are certain contraindications for bracing. Do not recommend plastic bracing if the patient has swelling of the lower extremities, insensate feet or compromised circulation. In our opinion, the condition of diabetes is also a valid reason for not prescribing a total contact plastic orthoses. Skin breakdown problems can be daunting and may ultimately lead to additional complications.

   The adaptation of new materials has provided us with a new option for the treatment of drop foot. Carbon fiber AFOs are very light and offer very good cosmesis. Although it may come in different designs, the single carbon upright extends from the foot plate and up the posterior portion of the leg. Using the stored potential energy principle at heel strike, the brace allows the foot to plantarflex as normal. When the foot is flat and subsequent to initiation of toe off, the brace coils and picks up the toe in time to offer clearance for swing through.

   The advantages of this brace are that it has minimal skin contact and is very comfortable for the patient to wear. The disadvantages include patient weight limitations as well as the need to avoid aggressive bending while hyperflexing, which may lead to brace failure.

   Negative aspects of conventional bracing include heaviness of the orthoses and the possible stigma of wearing braces. In general, patients quickly become accustomed to wearing this brace and find that the benefits outweigh the negatives.

A Closer Look At Medical Therapy Options

Alternative and adjunctive treatments may include oral antidepressants such as amitriptyline (Elavil, Merck), nortriptyline, gabapentin (Neurontin, Pfizer) and pregabalin (Lyrica, Pfizer). Other options are oral and topical non-steroidal anti-inflammatory drugs (NSAIDs) such as capsaicin, diclofenac, nabumetone (Relafen, GlaxoSmithKline), meloxicam (Mobic, Boehringer Ingelheim), a Flector patch (Pfizer) or a Lidoderm patch (Endo Pharmaceuticals).

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