Orthoses and FES are two treatment options clinicians can use to effectually treat patients with drop foot.
By Nathan Diffenbaugh, MSPT, DPT
When presented with a patient who has drop foot, what is the first method you think of for controlling this problem? Most clinicians picture a custom-fabricated Molded Ankle Foot Orthosis (commonly called a MAFO). You know what they look like—typically, a white or skin-tone thermoplastic brace with cloth straps. Perhaps it has a joint mechanism to allow for some active range of motion. Maybe the patient selected a transparency to give the brace a splash of color. Slide the MAFO into the shoe, and the patient is good to go. Problem solved.
From a mechanical standpoint, the MAFO is an excellent solution. It can prevent toe drag and assist in controlling genu recurvatum. This will allow for safer ambulation, which hopefully improves functional independence. The custom molding process allows for better fit of the brace and the opportunity to combine a variety of components that allow for improved function.
The sense of satisfaction that a therapist may feel upon delivery of the brace is not always shared by the patient. However, over time, they come to understand the benefit of the MAFO. Best-case scenario, the patient may be excited that first day when they start to take steps without having to worry about tripping over their toes. Worst-case scenario, some patients develop a strong dislike for their MAFO.
One of the most common complaints I hear is, “The thing is ugly.” Many times, the medical community forgets that patients are humans who share the same sense of vanity that we do. Would you want to wear a MAFO when dressing up for a special occasion? Honestly, a majority of MAFOs are neither attractive nor stylish. Another common, albeit justifiable, complaint is that the brace feels hot. Plastic does not breathe, so it is going to cause increased perspiration in the area that is covered. Depending on the thickness of the plastic or type of modifications utilized (such as joints), it may also feel heavy. Patients may also complain about the effort required to fit the brace into their shoe or to find a shoe that accommodates their brace.
There are many times when the most appropriate option for a patient is a custom MAFO. In these cases, it is the clinician’s job to explain the benefits of such a brace. Fortunately, the choices to control drop foot are expanding.
Benefits of Custom MAFOs
One such advancement is the use of carbon fiber to fabricate AFOs. Carbon fiber offers numerous advantages. It has the ability to absorb and then release stored energy.1 Various studies have found evidence that there are significant changes in gait speed and energy conservation compared to ambulation without a carbon fiber brace.2,3,4,5 The use of carbon fiber bracing allows the patient to reduce their workload during gait.6,7
There are drawbacks to the use of carbon fiber, however, that must be considered prior to ordering a brace. One problem is carbon fiber AFOs traditionally do not have a hinged ankle joint. Some patients may feel more comfortable walking with a MAFO that has a joint.8,9 There is also a risk that improper foot placement could cause the carbon fiber to snap under pressure. Another downside of most carbon fiber AFOs is a lack of customization. Many different companies offer braces that are prefabricated in various sizes. The practitioner selects the style they feel will work best and then orders the size which is most appropriate for the patient. Other than grinding the footplate to reduce the size, there are few modifications which can be made to accommodate the patient’s unique characteristics.
This is where Kinetic Research, based out of Lutz, Fla, offers a solution. Kinetic Research makes The Noodle family of braces. It offers six different styles of The Noodle, including a pediatric version. In addition to this, it has a variety of different bracing options that can be custom produced, including braces that utilize both carbon fiber and thermoplastic parts. A nice feature of The Noodle is that in addition to offering the standard off-the-shelf options for each brace, a practitioner can also order a custom-fabricated brace. This allows for improved patient fit. It may also allow for a more rigid style of brace to be fabricated compared to the standard off-the-shelf options.10
The company’s main selling point is a fabrication design that allows for more flexibility than standard carbon fiber AFOs. The different styles of the brace give clinicians the ability to choose a design which offers the optimal amount of support to meet the patient’s needs. Patients like the reduced weight of the carbon fiber compared to thermoplastic. Many also comment that the appearance of the carbon fiber is more pleasing and modern-looking compared to a standard MAFO.
Additional Orthoses for Drop Foot
The Germany-based company Ottobock also offers orthoses for the lower extremities, such as the WalkOn, which is a lower-leg orthosis designed to help lift and support light to severe drop foot. The lower-leg orthosis allows the user to complete daily tasks and walk more naturally.
Össur, headquartered in Reykjavik, Iceland, is another company that manufactures and sells bracing and support products. One such brace for the lower extremities is the Foot-Up, a lightweight, cushioned AFO intended to provide visible improvement in gait by supporting the foot the moment it is raised. Overall, the brace is engineered to offer dynamic support for foot drop. Braces are distributed and manufactured by other companies as well, including AliMed, Dedham, Mass; Allard, Rockaway, NJ; and DM Systems Inc, based in Evanston, Ill.
FES for Treatment of Drop Foot
Another option which is becoming more popular is the use of Functional Electrical Stimulation (FES) to control drop foot. This may be appropriate for individuals with a variety of neurological conditions, including stroke, traumatic brain injury, cerebral palsy, or multiple sclerosis. Studies have demonstrated functional gains which are similar to the use of standard bracing.4,5 Patients report improvements in gait stability and in their ability to perform their activities of daily living.6,8
Bioness Inc, Valencia, Calif, offers FES devices. The Bioness L300 and the recently added L300 Plus are convenient for both patients and clinicians. The L300 is composed of three parts: an electrical stimulation cuff, an intelli-sensor gait sensor, and a wireless control unit. The L300 Plus adds a thigh cuff to allow for stimulation of either the quadriceps or hamstrings during gait. The L300 offers either cloth or hydrogel electrodes to deliver the electrical stimulation.
The gait sensor is placed in the shoe of the affected leg, and detects the pressure changes that occur during heel lift. The cuff delivers FES that causes nerve excitement. Ultimately, this results in the muscle contraction for dorsiflexion during swing phase. Many patients comment that they like this device because it encourages the use of their muscles.11
Adjustments to the Bioness L300 take only a few minutes of clinical time, as it is easy to adjust the level and characteristics of stimulation needed for the patient. The control unit is plugged into the Clinicians Programmer (a pocket PC also known as a PDA). Patient compliance can even be monitored, since the L300 tracks the time used and the number of steps taken each day. As with any form of electrical stimulation, a patient’s tolerance to the modality needs to be taken into consideration.
Patients have to take proper care of the device. This includes wetting the cloth electrodes prior to use of the device and changing the electrodes roughly every 2 weeks. The cuff and the control unit have to be charged on a nightly basis in order to allow for proper battery function.
Another FES device intended for the treatment of drop foot is the WalkAide from Austin, Texas-based Innovative Neurotronics. WalkAide is designed to improve walking ability in individuals who are coping with upper motor neuron injuries or conditions such as stroke or TBI, and utilizes FES to restore typical nerve-to-muscle signals in the leg and foot, which results in a smoother, more natural motion. The Empi Continuum from Empi, a DJO Global company, Vista, Calif, is an electrical stimulation device designed for several rehabilitation therapies, including muscular re-education. This device produces an electrical reaction in motor nerves that activates and re-educates the muscle to improve function.
Considerations for Drop Foot Treatments
These products are just a few in the wave of new options to address the needs of individuals with drop foot. It is important to remember that one device is never the choice for every individual. Perhaps the greatest compliment that can be paid to these devices is in the level of independence that they provide for their users.
Patients often are opposed to anything that has a “medical” appearance. The sleek design of the carbon fiber in The Noodle offers more of an athletic brace appearance. Other patients have commented that they find the technology utilized in the L300 to be trendy. Granted, the appearance of a device does not impact its functionality, yet devices that appear more attractive may increase patient compliance with wearing recommendations. PTP
Nathan Diffenbaugh, MSPT, DPT, is employed by Lehigh Valley Health Network in Allentown, Pa. Diffenbaugh received his Masters of Science in Physical Therapy and his transitional Doctorate of Physical Therapy from Misericordia University. He specializes in treating patients with vestibular and neurological conditions. For more information, contact [email protected].
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