The total contact cast (TCC) has long been considered the criterion (gold) standard of nonremovable plantar pressure redistribution devices for patients with diabetic foot ulcers (DFUs) because it relieves excessive pressure that delays wound healing. In this issue of Advances, Thompson et al1 report 3.3 fewer days to DFU healing with a human cellular/tissue-based product and TCC, as compared with standard wound care and TCC (26.20 vs 29.50 days). They also discuss the reality of doing research with real-world patients: they began with a patient population of 270, with only 13 patients with DFUs consenting to TCC (4.8%).
Relieving pressure in the ulcer region (in this case, the foot) through the use of a TCC is one important component of wound healing. A regional assessment should examine the VIPs of DFU care: Vascular supply, Infection, and Plantar pressure redistribution.
Vascular supply is assessed with the ankle-brachial pressure index (ABPI). The Thompson study allowed ABPIs between 0.7 and 1.2, with large vessel values below 0.7 representing arterial predominant disease and a relative contraindication to the TCC; above 1.2 indicated calcified vessels and an inaccurate ABPI. The study also eliminated patients with an acceptable ABPI but who had gangrene, probably because of small vessel disease.1
Untreated and poorly controlled deep infection (especially osteomyelitis) is considered an important contraindication to TCC and may lead to tissue breakdown and deterioration of the foot. Accordingly, wound infection was another exclusion criterion in the Thompson study.1 Finally, plantar pressure redistribution with the TCC prevents treatment nonadherence because the device is irremovable.
The literature reveals interesting data as to why the TCC is not always used in clinical practice. Wu et al2 conducted a survey of facilities (N = 895) and found that 520 centers (58.1%) did not consider TCC the criterion standard for offloading noninfected plantar DFUs. Several factors resulted in only 1.7% of the centers using TCCs, including 55.3% patient tolerability (eg, unable to drive, bathing issues), 54.3% clinic application time, 31.6% cost of materials, 27.5% reimbursement issues, 25% lack of familiarity with TCC application, and 10.6% clinician coverage.
Fife at al3 conducted a retrospective review of DFU plantar pressure redistribution using a large database (11,784 patients; 25,114 DFUs; and 221,192 visits). Offloading was documented in 2.2% of the patient visits, and TCC was applied in 16% of documented cases. A variety of plantar pressure redistribution shoes were used; the postoperative shoe was most commonly applied (36%). The use of the TCC compared with alternate offloading was associated with the following:
- lower infection rates (1.6% vs 2.6%, P = 2.1 × 10–10)
- near-equal healing rates (39.4% vs 37.2%, not significant)
- fewer amputations (2.2% vs 5.2%, P = .001)
- increased application frequency using easy-to-apply kits versus traditional methods (6.2% vs 1.4%).
Given the low use of TCC, researchers have investigated the instant (irremovable) TCC (I-TCC), as reported by Katz et al4 as an alternative to TCC. Ingeniously, they modified a removable cast walker to make it nonremovable by applying fiberglass casting material. The study team evaluated 41 patients with DFU using this I-TCC compared with standard TCC. The ulcer healing rates were 94% and 93%, respectively, when patients lost to follow-up were excluded. The authors concluded that “the I-TCC may be equally efficacious, faster to place, easier to use, and less expensive than the TCC in the treatment of diabetic plantar neuropathic foot ulcers.”4
Further, Piaggesi et al5 evaluated 40 patients with DFUs over 12 weeks. They compared the TCC with the I-TCC. There were no significant differences in healing rates, healing time, or adverse events. The TCC cost €727 (US$811) and was applied in 15.1 minutes, compared with only €130 (US$145) and a 2.1-minute application time for the irremovable device. Overall, patients preferred the irremovable device.5
These data led us to ask ourselves: If TCC is underused in practice, is it really the criterion standard? Should the standard of practice change? And if a removable device is not associated with an acceptable healing rate, should patients and providers choose to make it nonremovable (I-TCC)? What do you think?
R. Gary Sibbald, MD, DSc (Hons), MEd, BSc, FRCPC (Med Derm), FAAD, MAPWCA, JM
Elizabeth A. Ayello, PhD, RN, CWON, ETN, MAPWCA, FAAN
1. Thompson P, Hanson DS, Langemo D, Anderson J. Comparing human amniotic allograft and standard wound care when using total contact casting in the treatment of patients with diabetic foot ulcers. Adv Skin Wound Care 2019;32:272–277.
2. Wu S, Jensen JL, Weber AK, Robinson DE, Armstrong DG. Use of pressure offloading devices in diabetic foot ulcers: do we practice what we preach? Diabetes Care 2008;31(11):2118–9.
3. Fife C, Carter MJ, Walker D, Thomson B, Eckert KA. Diabetic foot ulcer offloading: the gap between evidence and practice. Data from the US Wound Registry. Adv Skin Wound Care 2014;27:310–6.
4. Katz IA, Harlan A, Miranda-Palma B, et al. A randomized trial of two irremovable off-loading devices in the management of plantar neuropathic diabetic foot ulcers. Diabetes Care 2005;28(3):555–9.
5. Piaggesi A, Macchiarini S, Rizzo L, et al. An off-the shelf instant contact casting device for the management of diabetic foot ulcers: a randomized prospective trial versus traditional fiberglass cast. Diabetes Care 2007;30(3):586–90.