The diabetic population in the United States has grown to over 26 million people and 10 to 15 percent of this population will develop a diabetic foot ulceration (DFU).1,2 That would equal 2.6 to 3.9 million diabetic foot ulcerations in this country. Diabetic foot ulcerations precede 85 percent of all non-traumatic lower extremity amputations and it is known that patients with diabetes who have an amputation of the lower extremity will have a mortality rate of 45 percent in the next three to five years.3,4
Therefore, a diabetic foot ulceration is a life-threatening condition that carries a mortality rate that is actually greater than prostate and breast cancer combined.5 Accordingly, we as podiatrists need to take even the smallest diabetic foot ulceration very seriously.
Sheehan, Snyder and their respective colleagues have produced studies that indicate that if a DFU has not shown significant progress within four weeks and one week respectively of treatment, that the chance of the wound healing within 12 weeks is less than 10 percent.6,7 Additionally, Lavery and coworkers have shown that a DFU open for greater than 30 days has a 4.7 times greater risk of infection.8
In 1999, Margolis and colleagues reviewed 10 different DFU studies and extracted the control groups using standard “good” wound care, and evaluated the healing times.9 “Good” wound care included offloading, debridement, and a placebo gel or moistened saline gauze. Mean healing rates among the 10 studies revealed a meager 24.2 percent at 12 weeks and only 30.9 percent at 20 weeks.
We now practice in an age when evidence-based medicine is not just a catchphrase but dictates a necessary protocol for the many facets of medicine in our ever evolving litigious society. There are hundreds of topical wound dressings and treatments that claim superior wound healing. However, only three have met the rigorous FDA Premarket Approval, proving that they can reduce the time to healing of a diabetic foot ulcer. Of the three modalities to gain pre-market approval, the best healing rate was 56 percent of patients healed at three months.10
At this point, there is not a study that correlates the length of time a diabetic foot ulceration is open with the rate of amputation. It would seem obvious, however, that the longer a wound is present, the greater chance of infection and amputation.
Total contact casting (TCC) has long been referred to as the “gold standard” for treating non-infected, neuropathic foot ulcerations. This is for good reason. There are currently seven randomized, controlled trials that have validated the TCC’s efficacy as well as a meta-analysis with 498 patients that noted healing rates of 88 percent in a mean of 43 days.11-21 Of the seven randomized, controlled studies, the healing rates range from 34 to 58 days with 50 to 100 percent healed.
One of the studies by Armstrong and colleagues involved 63 patients with non-infected neuropathic plantar foot ulcers and compared the TCC with a removable cast walker (RCW) and a half shoe.11 All patients had follow-up for 12 weeks and weekly visits for wound care and debridement. The ulcer healing rate for the TCC patients was 89.5 percent in comparison to 65 percent for patients treated with a removable cast walker and 58.3 percent for patients treated with a half shoe.
Why Is The TCC So Effective?
Total contact casting has the ability to reduce plantar pressures, reduce shear, restrict ankle motion, shorten stride length and force adherence. Birke and coworkers reported that a total contact cast reduced pressures at the metatarsal heads in six normal, healthy patients by up to 84 percent.22 In a study comparing the TCC to running shoes, Hartsell and colleagues identified a 65 percent reduction in forefoot plantar pressures in the cast.23 Additionally, this study reported excellent reproducibility of load redistribution with TCC applications spaced one week apart and applied by the same technician. Wertsch and colleagues found a decrease in pressure in the first metatarsal head by 69 percent and in the heel by 45 percent with the use of a TCC.24
Although we do not currently have the ability to measure shear, one applies the TCC with intimate contact layers to the foot and leg, preventing motion within the cast. This close contact also increases the area of weight distribution, including the large surface area of the leg. This creates a “cone effect” or as we describe it to patients, “like putting a cork back into a wine bottle.” When patients stand on this cast, the leg portion of the cast itself takes a portion of their weight. This fixed ankle cast now eliminates the propulsive phase of gait and prevents the forces of equinus, which are common in our patients with diabetes.
As with most treatments, adherence is critical. Armstrong and colleagues proved that just making a controlled ankle motion (CAM) cast non-removable increased the rate of healing from 51.9 to 82.6 percent healed in 12 weeks.25
Overcoming The Hurdles To Using Total Contact Casts
So why don’t we see 3 million people in our country with total contact casts on their feet? In a 2008 study by Wu and coworkers that surveyed 895 podiatrists who perform diabetic wound care, only 1.7 percent employed the TCC for the majority of their diabetic foot ulcerations.26
The number of users is climbing, however, as sales of total contact cast kits are anecdotally showing a marked increase in the last few years. Total contact casting is also one of the few treatments that has had an increase in Medicare reimbursement to its providers.
The common excuses for not using the TCC are: knowledge and time of application, reimbursement issues, and the fear of creating additional wounds. These are just that — excuses. Total contact casting has been available for many years and is now available in kits with instructions. An even easier “roll-on” version is now available. The TCC-EZ (Derma Sciences) provides comparable efficacy to the standard TCC and is truly easier to apply.
In 2005, Guyton and colleagues addressed the issue of safety, concluding that “A frequently changed total contact cast is a safe modality for the offloading and immobilization of the neuropathic foot, albeit with an expected constant rate of minor, reversible complications.”27
Snyder and coworkers stated that “From a practical standpoint, more widespread adoption of effective offloading modalities would make the most positive improvement in DFU treatment.”28 In 2008, Warriner said, “This year, if there were only two things that we could institute in our 300 wound centers, it would be the following: 1. Non-invasive vascular assessment testing on new patients, 2. Offloading and shear reduction for diabetic foot ulcers utilizing the total contact cast.”29
These statements resonate the importance of this modality. We should not wait to use a TCC for the “train wreck” case as this too frequently leads to failure. We use the TCC as the first line of treatment in the office, even on new patients. Frequently, the small “simple” ulcers heal in just a couple weeks and patients are thrilled to have a wound healed that they had for months prior to their appointment. They quickly give up on protesting the cast after the first cast change when they find out the reduced measurement of the wound. Ultimately, the goal is to treat the neuropathic ulcer in a timely fashion to save limbs and save lives.
Dr. Jaakola is in private practice at the Diabetic Foot and Wound Center in Denver. He is a Fellow of the American College of Foot and Ankle Surgeons.
Dr. Weber is in private practice at the Diabetic Foot and Wound Center in Denver.
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29. Wound Care: The Practice and The Practical Workshop. June 15, 2011, Fort Worth, TX.