R.C. Marx and M. Mizel reply:
We would like to respond to Dr. Laborde's assertion of "the superiority of [Achilles] tendon lengthening over a total contact cast for the treatment of diabetic forefoot ulcers" as well as lend support to our statement that "total contact casting remains the gold standard treatment with which to offload Wagner grade-1 and 2 diabetic foot ulcers."
Treatment of diabetic foot ulcers is an enormous clinical challenge. The pathway toward ulcer formation involves a complex interaction between macro-angiopathic and micro-angiopathic systemic vasculopathy, diminished peripheral sensitivity and proprioception, and excessive plantar contact pressures on the forefoot that ultimately lead to breakdown of skin over osseous prominences1,2. Appropriate treatment of these ulcers involves a comprehensive approach including strict control of the diabetes, judicious use of surgical débridement and antibiotics when necessary, ostectomy of offending osseous prominences, and some form of pressure relief of the ulcerated foot1.
A time-honored approach to offloading a foot with a diabetic pressure ulcer is with the use of a total contact cast. While there is a paucity of Level-I trials, use of a total contact cast has become the most widely accepted treatment on the basis of available evidence and its durable clinical track record1,3. Multiple descriptive and controlled trials have demonstrated the relative safety and efficacy of total contact casts2,4. The documented rate of healing of primary diabetic foot ulcers following treatment with a total contact cast is approximately 90% at six weeks2,4,5. Despite its success with regard to the healing of ulcers, however, this treatment is associated with high recurrence rates, which make it an imperfect solution to a complex problem2.
There is a need for randomized controlled trials to directly compare Achilles tendon lengthening with use of a total contact cast. The last Cochrane Database Systematic Review on this subject underscored this need for more trials of high methodological quality in order to more confidently deliver treatment guidelines1. The lone randomized clinical trial cited by Dr. Laborde to support his assertions of the superiority of tendon lengthening over treatment with a total contact cast did not actually compare the two treatment modalities. Mueller et al., in a 2003 Level-I study, evaluated the ability of Achilles tendon lengthening used in conjunction with a total contact cast to reduce the rate of recurrence of diabetic foot ulcers2. This clinical trial is, to our knowledge, the only Level-I study evaluating Achilles tendon lengthening for the treatment of diabetic foot ulcers. Mueller et al. tempered the conclusions of their article, stating that Achilles tendon lengthening "should be considered as an adjunct to treatment with a total-contact cast in patients with a neuropathic plantar ulcer of the forefoot and limited ankle dorsiflexion (=5°) to decrease the rate of ulcer recurrence."
The concept of using Achilles tendon lengthening to offload diabetic foot ulcers in patients with concomitant ankle equinus contractures is compelling, and such lengthening may yet prove to be an invaluable adjunct to treatment with a total contact cast. However, at this point, we do not think that there is sufficient evidence to support the isolated use of Achilles tendon lengthening to treat diabetic foot ulcers. Currently, the efficacy of tendon lengthening alone in the treatment of neuropathic ulcers has been evaluated in only Level-III and IV studies6-9. While we recognize that Achilles tendon lengthening may play a role in the treatment of selected diabetic foot ulcers, at this point it does not have the clinical track record, or evidence, to displace the total contact cast as the "gold standard" treatment. We believe that any surgical procedure performed in these patients increases the possibility of the loss of the limb and any additional surgical intervention should be considered and applied cautiously.
We appreciate the opportunity to clarify our statements and will continue to address the relative merits of all treatment modalities concerning diabetic foot ulcers as the literature and evidence dictate.
These letters originally appeared, in slightly different form, on . They are still available on the web site in conjunction with the article to which they refer.