Current guidelines strongly recommend regular, sharp debridement of diabetes-related foot ulcers (DFU) when blood flow is adequate (1). Sharp debridement disrupts biofilm and removes nonviable tissue, callus, and senescent cells, preparing the wound for endogenous healing (2) and advanced wound-healing therapies (3). Despite a reported association of more frequent debridement with improved healing outcomes (4), published prospective, randomized studies to inform optimal debridement frequency are absent, and existing evidence is rated as low (1).

A prospective, multicenter intervention study was conducted to determine the effect of sharp debridement frequency on healing outcomes in participants with DFU, randomized to weekly debridement or every second week debridement.

Adults with diabetes and a plantar neuropathic foot ulcer of ≥2 weeks’ duration and ≥0.5–10 cm2 in size were included. Exclusion criteria were nonhealing despite ≥6 months of treatment, moderate or severe ischemia, moderate or severe infection, nonplantar location, and/or inability to follow the protocol, including weekly visits.

Computer-generated, block randomization, 1:1 to either weekly or every second week debridement, with stratification factors of treatment center and DFU size (<3 cm2 or ≥3 cm2), was used. A participant sample size of 120 was sought, with 85% power to detect a between-group 30% healing difference at 12 weeks, allowing for a 20% study dropout.

All study sites adhered to a state-approved model of care for interdisciplinary high-risk foot services (5) and documented treatment standards: pressure offloading using removable knee-high or ankle-high devices both with rocker soles and insoles (standardized), oral antibiotics when indicated, dressings (excluding those that debride), and systemic diabetes care. The debridement method was removal of nonviable tissue from the wound base and periphery using scalpel, curette, and forceps. Self-reported adherence to wearing the offloading devices was recorded as the percentage of waking hours that the device was worn. All participants attended weekly.

Digital images were taken at baseline, 4 weeks, and 12 weeks or when the treating clinician deemed the ulcer had healed (whichever came first). Healing was defined as complete epithelialization of the wound with no exudate that would require dressing. All digital images were assessed by two independent wound experts, blinded to treatment allocation. Healing outcomes were recorded in the medical record by treating clinicians and reported as a site-assessed healing outcome. The predefined secondary outcome measures of percentage of wound area reduction at weeks 4 and 12 were calculated from real-time wound tracings.

A statistical analysis plan was developed prior to any data unblinding, and comparisons of primary and secondary outcomes between groups were analyzed according to the principle of intention to treat. All comparisons were two-sided together with corresponding 95% CI, and P values of <0.05 were considered statistically significant.

The study protocol was registered on the Australian New Zealand Clinical Trials Registry (https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=367 998) and approved by the Royal Prince Alfred Hospital ethics committee (X14-01 84&HREC/14/RPAH/242) as the lead site, with local-site governance approval at each participating center.

In total, 122 participants (n = 61 per group) were recruited between October 2015 and September 2019 from seven treatment sites. Between-group participant and wound baseline characteristics were well matched (Table 1). Thirteen (11%) participants dropped out of the study with no outcome data for analysis (n = 3 in the weekly and n = 10 in the every second week debridement group). Overall, 75.4% (n = 92) completed each protocol. Digital images were available for assessment for only n = 78 participants.

Using a modified intent-to-treat analysis excluding participants whose healing outcome was not known, 53% (n = 24/45) in the weekly group and 52% (n = 17/33) in the every second week group healed by 12 weeks (mean difference 1.8%, 95% CI −16.3–20.0%, P = 0.84), according to assessment of digital images. Using clinician, site-assessed outcomes, 52% (n = 30/58) healed in the weekly and 45% (n = 23/51) in the every second week group (mean difference 6.6%, 95% CI −7.9–21.1%, P = 0.37). The secondary outcome of percentage of wound area reduction at week 12 showed a nonsignificant higher clinical closure rate (80.6% vs. 65.6%) in the more frequently debrided group (mean difference 15%, 95% CI −11.6–41.7%, P = 0.27). No on-study amputations occurred.

Study strengths include its pragmatic design with representative patients receiving contemporary management. Study limitations include use of removable pressure-offloading devices (Table 1); however, use of irremovable devices would have limited recruitment only to participants able to accept and use such methods.

Sharp debridement is optimally provided by skilled clinicians in the multidisciplinary setting, necessitating recurrent presentation to a clinic. Consequently, debridement frequency and clinic presentation are closely aligned. Debridement frequency has substantial implications for patients, their families, and health care provider cost and workforce requirements. While weekly debridement may be of benefit if individual wound and patient factors warrant it, this study shows that weekly debridement is not superior to debridement every second week. A good rate of ulcer healing is achieved with standardized care that includes both weekly and every second week debridement regimens.

Clinical trial reg. no. ACTRN12618000703202, www.anzctr.org.au

Acknowledgments. The following clinicians supported the conduct of the study: Anna Crawford, Jessica Kronenberg, Sarah Manewell, Purnima Rao, and David Wong. Purnima Rao collated and entered data. Michelle Barakat-Johnson and Jana Pinkova assessed digital images for the primary outcome. Participating site investigators include Danielle Veldhoen and Louise Pfrunder (Royal Prince Alfred Hospital), Georgina Frank (Concord Hospital), Cindy Meler, Luke Taylor and Ashish Gargya (Bankstown Hospital), Julie Zwarteveen and Kate Carroll (John Hunter Hospital), Alan Kennedy (St. George Hospital), Jill Featherston and Joel Lasschuit (St. Vincent’s Hospital), and Jacqueline Batchelor and Catherine Stephens (Hornsby Hospital).

Funding. Funding support came from NSW Health, Office of Health and Medical Research, competitive Translational Research Grants Scheme, recipient number 96. There was no funding body involvement in study conduct, with the exception of the rules governing ethical conduct of the research. This funder did not have a role in the analysis or interpretation of the data, writing of the manuscript, or decision to submit for publication. There was in-kind support from the Sydney Local Health District and participating hospitals. The funding was used for consumables, offloading, partial clinical backfill for investigators, a study coordinator, external randomization, and data analysis services from the National Health and Medical Research Council Clinical Trials Centre, The University of Sydney. There has been no payment to write this article.

Duality of Interest. No potential conflicts of interest relevant to this article were reported.

Author Contributions. V.L.N., D.V., and S.M.T. designed the study protocol and prepared submissions for ethics. V.L.N., D.V., C.M., G.F., J.F., and J.B. collected data and provided oversight of the study at their site. J.M.W. contributed to coordination and data management of the study. V.L.N., K.B., V.G., and S.M.T. contributed to and approved, and K.B. and V.G. wrote, the statistical plan. K.B. and V.G. analyzed the data. V.L.N., V.G., J.A.A., and S.M.T. interpreted the data. V.L.N. wrote the manuscript, and S.M.T. contributed to the manuscript and discussions. All authors approved the manuscript. S.M.T. is the guarantor of this work and, as such, had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Prior Presentation. Parts of this study were presented in abstract form at the Australasian Diabetes Congress, 11–13 November 2020.

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