SLR - February 2016 - Ariel Lepoff

Title: Treatment of Chronic Plantar Ulcer of the Diabetic Foot Using an Irremovable Windowed Fiberglass Cast Boot: Prospective Study 177 Patients

Reference: Ha Van G, Michaux C, Parquet H, Bourron O, Pradat-Diehl P, Hartemann A. Treatment of Chronic Plantar Ulcer of the Diabetic Foot Using an Irremovable Windowed Fiberglass Cast Boot: Prospective Study 177 Patients. Diabetes Metab Res Rev. 2015 Oct; 31(7): 691-698.

Scientific Literature Review

Reviewed By: Ariel Lepoff, DPM
Residency Program: Aventura Hospital and Medical Center

Podiatric Relevance: Chronic non-healing ulcers present a challenge to all podiatric physicians due to patient co-morbidities leading to altered healing potential and patient non-compliance. Total contact casting yields the highest rates of diabetic pressure ulcer healing but is used in less than 2 percent of cases in over 800 diabetic foot centers. This is likely due to the fact that it is time consuming to apply a leg cast that is thoughtfully modified for pressure specific offloading which then must be repeated every two weeks. Further, it does not allow for any monitoring of the wound between visits. The high healing rates associated with TCC is likely related to the paradigm that the only way to heal a pressure ulcer is to eradicate pressure. By the same token, the only way to heal a pressure ulcer in a non-compliant patient is to mandate pressure offloading. In this study, a method utilizing forced compliance by way of a single cast application, with an open window over the wound for constant monitoring, presents an interesting alternative to TCC that may be more conducive for the physician’s time management.

Methods: This study comprised a single center prospective study of a cohort of 177 diabetic patients with chronic neuropathic ulcers from 1997 to 2010. Patients were admitted to the study if their neuropathic ulcer was ongoing for greater than three months, had recurred due to non-compliance, or if it was a sequela of Charcot neuroarthropathy. Inclusion criteria allowed for slightly infected wounds, moderate PAD, as well as patients who were status post ostectomy of osteomyelitis. The ulcers were characterized as an average duration of 604±808 days, a mean surface area of 4.6±6.5cm2 with a depth of 1.04±1.08cm. Patients wore an irremovable fiberglass cast for an average of 96 days. Once the below the knee cast was applied over a 90 to 120-minute single time session, the patient was followed up at the Diabetic Foot Unit eight, 15, and 30 days later, then once monthly. A home nurse provided daily to every other day dressing changes.

Results: The level of healing as defined in the study by complete re-epithelialization was 83.6 percent. Sixteen and four tenths percent did not heal and of those 29 patients, the average length which they wore the cast was not statistically significant (74.4±62.8 days) in comparison to those that did heal (96±94 days). The location of the ulcer did preclude to significantly slower healing rates with 40 percent of heel ulcers remaining unhealed. However, most heel ulcers were almost twice the volume in comparison to ulcers of other locations. It was confirmed that volume was significantly greater in wounds that were not healed (7.6±12.9 vs 5.6±18.6). It remains unclear whether it was the increased volume, the proximal location, or a combination of the two which delayed healing the most. Also, the presence of moderate PAD defined by several variable including an ABI between 0.5 to 0.9, or history of surgical resection of osteomyelitis prior to the study did not significantly affect the outcome of healing. Overall, patient compliance was 95 percent. Adverse events noted in the study included 26 cast changes (14.6 percent), 12 superficial (7 percent) and two neuropathic pressure ulcers (1 percent) became infected, and six toes amputations (4 percent). Only nine patients were non-compliant in the study leading to an overall compliance rate of 95 percent.

Conclusions: Total contact casting remains the gold standard in the treatment of diabetic neuropathic plantar ulcers with a healing rate of 90 percent over 42±29 days with cast replacement every 10-15 days. In comparison, this study had a slightly lower healing rate of 83.6 percent over a more protracted amount of time. The authors of this paper theorized the disparity lie in the volume of the wounds. Previous published material on TCC included wounds with a surface area of 1-2cm2 versus the average surface area of wounds presented in this article measuring 4.6±6.5 cm2. This concept was echoed with respect to comparison of healing rates of the heel wounds which had a significantly lower healing rate thought to be a consequence of larger volumes. Nevertheless, this concept may be worthwhile for lower volume wounds in non-compliant patients where a cast change cannot be performed every two weeks.

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