Can Bracing Have An Impact For The Charcot Foot?
The primary plane of deformity may also influence the success or failure that one may achieve with bracing. Typically, sagittal plane deformities, if stable, may respond to bracing more readily than transverse plane deviations or a combination of the two. Oftentimes, a more limited surgical intervention, such as an exostectomy, may prove helpful in eliminating a plantar prominence and rendering the patient more amenable to bracing, and with less risk than a full reconstructive surgery.
There are three primary forces that may act to disrupt a neuropathic foot. These forces are shearing, bending and vertical load. One may adequately control shearing forces with accommodative innersoles or orthotics. Studies in normal feet have demonstrated that clinicians can also neutralize shearing forces with an ankle foot orthosis (AFO).1
In my opinion, the most destructive force in many neuropathic feet is an excessive bending force, typically mitigated by ankle equinus and the tight Achilles tendon. This is a key factor in the development of the initial collapse and will also serve to render the patient susceptible to subsequent problems even after the initial fracture/dislocation has healed. In some instances, one may employ a tendo-Achilles lengthening via local anesthesia even if the patient is not a candidate for more aggressive intervention. Post-op bracing may help protect the foot. Conservative options for neutralizing the effects of ankle equinus include elevation of the heel of the shoe. Typically, a 1-inch elevation of the heel over the sole of the shoe is sufficient.
Pertinent Insights On Bracing Options
In addition to the cited literature below, the options and preferences I discuss below are based on my experience with these devices. There are many different bracing options available and each physician may find that different options work effectively in his or her own experience.
Ankle foot orthosis. An AFO is a very simple means of reducing stress to the foot and ankle with weightbearing. Landsman and Sage found success in healing recalcitrant ulcers in neuropathic patients using an AFO.2 Furthermore, their study showed a 72 to 90 percent reduction in peak pressures at the ulcer sites in comparison to the use of shoes with Plastazote liners alone. Researchers have also shown that AFO devices limit mobility in all three planes within the rearfoot and midfoot in normal patients.1 In a study of 20 asymptomatic patients, Kitaoka and colleagues found that the AFO limited sagittal and coronal plane ankle-hindfoot motion. At the midfoot, they noted the AFO limited transverse motion. One would presume a similar response would occur in Charcot patients.
An AFO is very light, fairly inconspicuous with shoes and slacks, and many patients accept it fairly well. The main problem with the device is that many Charcot patients have deformity within the foot that requires accommodation with an orthotic or a deep Plastazote liner to prevent local irritation and ulceration. Adequate protection of the deformed foot is oftentimes difficult to achieve with the hard plastic of the AFO. Furthermore, accommodation for ankle equinus more readily occurs via other measures in comparison to an AFO. Therefore, I have found that many patients with Charcot deformity simply have conditions for which an AFO is not the optimal device.