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Diabetic foot and wound assessment: stick and rudder or instrument-rated?

David G Armstrong
I was recently reminded of a wonderful, lively, high-level discussion many years ago at the Symposium on Advanced Wound Care in Dallas on the new era of diagnostics and ‘theragnostics’ to better allow us to measure what we manage. Let me summarise that discussion in this editorial.

I was recently reminded of a wonderful, lively, high-level discussion many years ago at the Symposium on Advanced Wound Care in Dallas on the new era of diagnostics and ‘theragnostics’ to better allow us to measure what we manage (Armstrong, 2011). Let me summarise that discussion in this editorial.

Diabetic foot ulcers occur and recur on the foot because of a multitude of factors (Figure 1). These include, but are not limited to, neuropathy, deformity, increased stress and peripheral artery disease (Armstrong et al, 2017). When present, current methods to assess progress have often been limited to visual cues. Even when measurement occurs, it is frequently inaccurate, leading to difficulties in measuring what we manage (Rogers et al, 2010; Armstrong et al, 2015).

Other promising techniques, such as assessment of serine and matrixmetalloprotease levels (Salvo et al, 2017), TNF-alpha (Salvo et al, 2017), thermometry (Armstrong and Lavery, 1996; Sibbald et al, 2015; Salvo et al, 2017), C-reactive protein (Salvo et al, 2017), bacterial load (Gardner et al, 2013; Spichler et al, 2015), biopsies to identify viable growth factor receptor expression (Brem and Tomic-Canic, 2007; Ramirez et al, 2015), nitric oxide or other analytes (Margolis et al, 2017) and even wound pH (Schneider et al, 2007; McArdle et al, 2014) have not yet been sufficiently quantified or gained widespread acceptance (Serena et al, 2016).

Over the past generation, many potential therapeutics have been developed by device and biotechnology industry collaborators. What has been lacking, in our view, has been sufficient attention to what may be best termed ‘companion diagnostics’ (Armstrong and Giovinco, 2011; Armstrong et al, 2013; 2015; Izzo et al, 2014).

The fact is that, despite efforts over the past few years, the bulk of our assessments are visual and empiric in nature. In many ways, we’re like early aviators — strictly piloting our patients by ‘visual flight rules’ without the benefit of instruments (Ottati et al, 1999). While I would suspect this is a romantic notion for clinicians, I would argue that the stick and rudder method of caring for patients ought to allow for a bit more navigational assistance from instruments. With the impending arrival of new diagnostics and ‘theragnostics’ to assist us in quantifying inflammation, infection, blood flow, and presence and quantity of ‘receptive receptors’, perhaps we can now augment our stick and rudder skills with an ‘instrument rating’ (Weislogel and Miller, 1970). I would hope this will allow us to fly through those therapeutic cloud banks where our visibility is limited. Here’s to that next jump in wound navigation.


Armstrong DG, Lavery LA (1996) Monitoring neuropathic ulcer healing with infrared dermal thermometry. J Foot Ankle Surg 35(4): 335–8; discussion 372–3
Armstrong DG (2011) Wound Healing: Stick and Rudder Visual Cues or Instrument-Rated? DF Blog. Available at: (accessed 03.01.2018)
Armstrong DG, Giovinco NA (2011) Diagnostics, theragnostics, and the personal health server: fundamental milestones in technology with revolutionary changes in diabetic foot and wound care to come. Foot Ankle Spec 4(1): 54–60
Armstrong DG, Kanda VA, Lavery LA et al (2013) Mind the gap: disparity between research funding and costs of care for diabetic foot ulcers. Diabetes Care 36(7): 1815–7
Armstrong DG, Lew EJ, Hurwitz B, Wild T (2015) The quest for tissue repair’s holy grail: The promise of wound diagnostics or just another fishing expedition? Wound Medicine 8: 1–5
Armstrong DG, Boulton AJ, Bus SA (2017) Diabetic foot ulcers and their recurrence. N Engl J Med 376(24): 2367–75
Brem H, Tomic-Canic M (2007) Cellular and molecular basis of wound healing in diabetes. J Clin Invest 117(5): 1219–22
Rogers LC, Bevilacqua NJ, Armstrong DG, Andros G (2010) Digital planimetry results in more accurate wound measurements: a comparison to standard ruler measurements. J Diabetes Sci Technol 4(4): 799–802
Salvo P, Dini V, Kirchhain A et al (2017) Sensors and biosensors for C-reactive protein, temperature and pH, and their applications for monitoring wound healing: a review. Sensors (Basel) 17(12). doi: 10.3390/s17122952
Sibbald RG, Mufti A, Armstrong DG (2015) Infrared skin thermometry: an underutilized cost-effective tool for routine wound care practice and patient high-risk diabetic foot self-monitoring. Adv Skin Wound Care 28(1): 37–44
Gardner SE, Hillis SL, Heilmann K et al (2013) The neuropathic diabetic foot ulcer microbiome is associated with clinical factors. Diabetes 62(3): 923–30
Spichler A, Hurwitz BL, Armstrong DG, Lipsky BA (2015) Microbiology of diabetic foot infections: from Louis Pasteur to ‘crime scene investigation’. BMC Med 13(1): 2
Ramirez HA, Liang L, Pastar I et al (2015) Comparative genomic, microRNA, and tissue analyses reveal subtle differences between non-diabetic and diabetic foot skin. PLoS One 10(8): e0137133
Margolis DJ, Hampton M, Hoffstad O et al (2017) NOS1AP genetic variation is associated with impaired healing of diabetic foot ulcers and diminished response to healing of circulating stem/progenitor cells. Wound Repair Regen 25(4): 733–6
Schneider LA, Korber A, Grabbe S, Dissemond J (2007) Influence of pH on wound-healing: a new perspective for wound-therapy?  Arch Dermatol Res 298(9): 413–20
McArdle C, Lagan KM, McDowell DA (2014) The pH of wound fluid in diabetic foot ulcers- the way forward in detecting clinical infection? Curr Diabetes Rev 10(3): 177–81
Serena TE, Cullen BM, Bayliff SW et al (2016) Defining a new diagnostic assessment parameter for wound care: elevated protease activity, an indicator of nonhealing, for targeted protease-modulating treatment. Wound Repair Regen 24(3): 589–95
Izzo V, Meloni M, Vainieri E et al (2014) High matrix metalloproteinase levels are associated with dermal graft failure in diabetic foot ulcers. Int J Low Extrem Wounds 13(3): 191–6
Ottati WL, Hickox JC, Richter J (1999) Eye scan patterns of experienced and novice pilots during visual flight rules (VFR) navigation. In: Proceedings of the Human Factors and Ergonomics Society Annual Meeting. Vol 43. SAGE Publications Sage CA: Los Angeles, CA pp66–70
Weislogel GS, Miller JM (1970) Study to Determine the Operational Profile and Mission of the Certificated Instrument Rated Private and Commercial Pilot. Ohio State University Columbus Department of Aviation. Available at: (accessed 08.02.2018)

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