A Closer Look At Bone Stimulators For Charcot

By Michael S. Downey, DPM, FACFAS

     In one of the better reports on this topic, Hanft, et. al., investigated the role of bone growth stimulation as an adjunct in managing the Charcot foot.10 The study included 31 patients. The first 21 subjects were randomized into the study or control groups. All 21 patients had diabetic neuropathy involving their lower extremities, accompanied by clinical and radiographic findings of stage 1 Charcot osteoarthropathy involving the foot and/or ankle.

     The investigators immobilized all of the patients with a total contact cast or a fixed ankle walker with a contact molded multi-density thermoplastic insole. All of the patients also received compression stockings to help control the edema present. The researchers also uniformly instructed the patients to decrease their level of ambulation and weightbearing at 50 percent of what they were doing prior to treatment.

     The study group received one additional modality, an Orthologic® combined magnetic field bone growth stimulator, which was not given to the control patients. This device was used for 30 minutes daily. After researchers studied and href="/files/photos/ pt1206charcot4.jpg" rel="lightbox">statistically evaluated the initial 21 patients, they enrolled 10 additional patients as study candidates, all of whom received bone growth stimulation.

     Researchers examined several areas between the treatment group (21 cases) and the control group (10 cases) including:
     • the duration of Charcot osteoarthropathy prior to the start of treatment;
     • the patient age;
     • the rate of consolidation of insulin-dependent patients with diabetes versus non-insulin dependent patients with diabetes in each group;
     • obesity as a factor in consolidation time;
     • total contact cast versus fixed walker as a factor in the consolidation time; and
     • time to consolidation in patients receiving bone growth stimulation versus those not receiving bone growth stimulation.

     The results of the study revealed that the mean time to consolidation for the treatment group was 11.0 weeks versus 23.8 weeks in the control group. This 12.8-week difference between the groups was statistically significant. With the exception of the application of the bone growth stimulation, all the other variables studied had no statistically significant effect on the time to consolidation. The authors also noted that the treatment group had less deformity at the completion of the study than the control group and were able to resume ambulation in less time.

Can Pulsed Electromagnetic Field Bone Growth Stimulation Have An Impact?

     In 2000, Grady, et. al., investigated the use of pulsed electromagnetic field bone growth stimulation in patients with Charcot osteoarthropathy.11 The authors reported on a series of 11 patients who all received PEMF bone growth stimulation in combination with some form of immobilization. Eight patients had stage 1 Charcot osteoarthropathy and three patients had a stage 2 Charcot deformity. The immobilization consisted of either an Equalizer Walker or an Unna boot with a surgical shoe. The patients were allowed to bear weight in their immobilization device.

     Every four weeks, radiographs assessed the Charcot deformity. The mean time for radiographic consolidation of the Charcot deformity was 3.5 months among the 11 patients. The researchers continued the bone growth stimulation until there was clinical resolution of edema, erythema and crepitus. They followed the patients in their series for a mean of 18 months with one of the 11 patients having a recurrent acute Charcot episode after nine months.

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