Validation of Wagner's Classification: A Literature Review

Author(s): 
Robert G.Smith,DPM,RPh,CPed

P ractitioners attempt to provide care diligently, honestly, and sincerely. Clinical decision-making is an important tool used during treatment. Keenan and Redmond1 refer to the evaluation of evidence as one key factor that governs clinical decision-making. To ensure high quality care, Baxter and Baxter2 instruct practitioners to base their practice on sound clinical evidence. Redmond et al3 extends the concept because podiatrists rely on quantitative measurements when evaluating clinical research; these measurements must be accurate, reliable, and valid. Clinimetrics, the development and evaluation of measurements,4 may be applied to wound assessment tools such as diabetic foot ulcer classification systems.

Mulder5 acknowledges the existence of national guidelines for the treatment of chronic wounds. The Agency for Health Care Policy and Research6 and the National Pressure Ulcer Advisory Panel provide these practice guidelines.7 Zulkowski et al8 report that these guidelines are not designed to direct assessment of foot ulcers. The International Working Group on the Diabetic Foot agreed on 43 standard definitions for treating diabetic feet.9 However, a classification system for diabetic foot ulcers was not included because no one has documented having enough clinical experience with one system to validate or endorse it.10 Although many diabetic foot ulcer classifications are available, few have been clinically tested.

The first classification systems developed and accepted by clinicians were Meggitt's11 and Wagner's.12,13 The Wagner system is taught in podiatry colleges in the United States. The Wagner system is a source of questions used on the American College of Foot and Ankle Orthopedics and Medicine Board examination and has been introduced as evidence in United States' court proceedings.14

The purpose of this review is to present the Wagner dysvascular foot classification system, discuss its clinimetric properties, and examine existing validation literature of the Wagner and other diabetic classification systems.

Meggitt-Wagner Classification

Of the many diabetic wound classification systems available today, the Meggitt-Wagner Classification is the one most often cited. This system was first described by Meggitt11 and subsequently universalized by Wagner.13 The natural history of dysvascular foot breakdown is divided into six grades ranging from Grade Zero to Grade Five. For comparison purposes, both classification systems are presented in Figure 1. The Wagner system is similar to an ordinal scale denoting ranked order, allowing for nonparametric data analysis.15,16 Grade is determined based on depth of the skin lesion and the presence or absence of infection and gangrene.13,17

Both Meggitt's11 and Wagner's13 systems allow for bidirectional progression from Grade Zero to Grade Four and regression from Grade Four to Grade Zero. The property of bidirectionality is not generally accepted as a positive attribute to a classification system. One reason is that many third-party reimbursement plans are tied to a particular wound description or class. However, the original intent of Meggitt's11 and Wagner's13 was to allow for descriptionof the dysvascular foot over a period of time pre- and postsurgery and for nonsurgical interventions.11,13 Wagner's classification system is a visual one, implemented without the aid of an objective precision device like a ruler, grid, or measuring tape. Subjective in nature, it may be considered a noncontact measurement system. Jeffcoate et al18 considers this subjectivity a major disadvantage of the system. Initially, this subjectivity may present reliability concerns.

References: 

1. Keenan AM, Redmond AC. Integrating research into the clinic: what evidence based practice means to the practicing podiatrist. Journal of the American Podiatric Medical Association. 2002;92(2):115-122.
2. Baxter R, Baxter H. Evidence-based practice. J Wound Care. 2002;11(1):7-9.
3. Redmond AC, Keenan AM, Landorf K. Horses for courses: the differences between quantitative and qualitative approaches to research. Journal of the American Podiatric Medical Association. 2002;92(3):159-169.
4. Clinimetrics Research Associates, Inc. 2000. Http://www.clinimetrics.com/biostat/biostat.htm. Accessed March 30, 2002.
5. Mulder GD. Standardizing wound treatment procedures for advanced technologies. Journal of the American Podiatric Medical Association. 2002;92(1):7-11.
6. Bergstrom N. Treatment of pressure ulcers. Clinical practice guideline, 1994; No 15. AHCPR Publication No. 95-0652. Rockville, Md.: Agency for Health Care Policy and Research; 25-31.
7. National Pressure Ulcer Advisory Panel. Pressure ulcers: incidence, economics, risk assessment. Consensus development conference statement. West Dundee, Ill.: S-N Publications;1989:3-4.
8. Zulkowski KM, Tellz R, van Rijswijk L. Documentation with MDS section M: skin condition. Advances in Skin and Wound Care. 2001;14(2):81-89.
9. International working group on the diabetic foot. A consensus document of a leading group of scientists on the diabetic foot, intended for global implementation. International Working Group on the diabetic foot. Maastricht, The Netherlands;1999.
10. Apelqvist J, Bakker K. Comment from International Editorial Board members: There is a need for classification systems for clinical and research purposes. The Diabetic Foot. 2000;3(1):10-11.
11. Meggitt B. Surgical management of the diabetic foot. Brit J of Hosp Med. 1976;16:227-232.
12. Wagner FW. Classification and treatment program for diabetic, neuropathic and dysvascular foot problems. Instructional Course Lectures 28. American Academy of Orthopaedic Surgeons;1979.
13. Wagner FW. The dysvascular foot: a system for diagnosis and treatment. Foot and Ankle. 1981;2(2):64-122.
14. Keep JN . "Mckitty et al versus Advance Tissue Sciences, Incorporated et al." Docket No. 1998; 98-CV-1146, S.D. Calif. Court. http://securities.stanford.edu/1010/ATIS98. Accessed April 1, 2002
15. Gaddis ML, Gaddis GM. Introduction to biostatistics: part 1. Basic concepts. Ann Emerg Med. 1990;19(1)86-89.
16. Gaddis GM, Gaddis ML. Introduction to biostatistics: part 2. Descriptive statistics. Ann Emerg Med. 1990;19(3):309-315.
17. Armstrong DG, Peters EJG. Classification of wounds of the diabetic foot. Current Diabetes Reports. 2001;1(3):233-238.
18. Jeffcoate WJ, Macfarlane RM, Fletcher EM. The description and classification of diabetic foot lesions. Diabetic Medicine. 1993;10(7):676-679.
19. Yarkony GM, Kirk PM, Carlson C, et al. Classification of pressure ulcers. Arch of Dermatol. 1990;126(9):1218-1219.
20. Altman DG, Bland JM. Diagnostic tests 1: sensitivity and specificity. Brit Med J. 1994;308 (6943):1552.
21. Altman DG, Bland JM. Diagnostic test 2: predictive values. Brit Med J. 1994;30(6947):102.
22. van Rijswijk L. Wound assessment and documentation. In: Krasner DL, Rodeheaver GT, Sibbald RG (eds). Chronic Wound Care: A Clinical Source Book for Healthcare Professionals, Third edition. Wayne, Pa.: HMP Communications;2001:101-115.
23. Lazarus GS. Cooper DM, Knighton DR, et al. Definitions and guidelines for assessment of wounds and evaluation of healing. Arch of Dermatol. 1994;130(4):489-493.
24. Hess CT. Wound Care: Nurse's Clinical Guide. Springhouse, Pa.: Springhouse Corporation; 1995:260.
25. Sussman C. Assessment of the skin and wound. In: Sussman C, Bates-Jensen BM (eds). Wound Care: A Collaborative Practice Manual for Physical Therapists and Nurses, First edition. Gaithersburg, Md.: Aspen Publishers;1998:49-82.
26. Hetherington VJ. The neuropathic foot. In: McGlamry ED, Banks AS, and Downey MS (eds). Comprehensive Textbook of Foot Surgery, 2nd ed. Baltimore, Md.: Williams and Wilkins;1992:1352-1358.
27. Browne AC, Sibbald RG. The diabetic neuropathic ulcer: an overview. Ostomy/Wound Management. 1999;45(Suppl 1A):6S-20S.
28. Armstrong DG, Lavery LA, Harkless LB. Validation of a diabetic wound classification system: the contribution of depth, infection and ischemia to risk of amputation. Diabetes Care. 1998;21(5):855-859.
29. McDermott J, McDermott MA. Effects of diabetes on the foot. In: Janisse D (ed). Introduction to Pedorthics. Columbia, Md.: Pedorthic Footwear Association;1998;69-78.
30. Riegelman RK, Hirsch RP (eds). Studying a Study and Testing a Test: How to Read the Medical Literature. 2nd ed. Boston, Mass.: Little, Brown and Company;1989:327-338.
31. Yu A. Educational assessments: reliability and validity. Available at: http://seamonkey.ed.asu.edu/alex/teaching/assessment/reli62 Ostomy Wound Management ability.html. Accessed April 19, 2002.
32. Neufeldt V, Sparks AN (eds). Webster's New World Dictionary. 1st ed. New York, NY: Pocket Books Paperbacks;1995:497.
33. Lacity M, Jansen MA. Understanding qualitative data: a framework of text analysis methods. J of Man Inform Sys. 1994;11:137-160.
34. Messick S. Validity of psychological assessment: validation of inferences from person's responses and performance as scientific inquiry into scoring meaning. Am Psychologist. 1995;9:741-749.
35. Calhoun JH, Cantrell J, Cobos J, Lacy J, et al. Treatment of diabetic foot infec-tions: Wagner classification, therapy, and outcome. Foot and Ankle. 1988;9(3):101-106.
36. Pittet D, Wyssa B, Herter-Clavel C, et al. Outcome of diabetic foot infections treated conservatively: a retrospective cohort study with long-term follow-up. Arch Intern Med. 1999;159(8):851-856.
37. Oyibo SO, Jude EB, Tarawneh I, Nguyen HC, Harkless LB, Boulton AJM. A comparison of two diabetic foot ulcer classification systems. Diabetes Care. 2001;24(1):84-88.
38. Margolis DJ, Berlin JA, Strom BL. Interobserver agreement, sensitivity, and specificity of a "healed" chronic wound. Wound Rep and Regen. 1996;4(3):335-338.
39. Cavanagh PR, Simoneau GG, Ulbrecht JS. Ulceration, unsteadiness, and uncertainty: the biomechanical consequences of diabetes mellitus. J of Biomech. 1993;26(Suppl 1):23-40.
40. Oyibo SO, Jude EB, Tarawneh I, Nguyen HC, Harkless LB, and Boulton AJM. The effect of ulcer size and site, patient's age, sex and type and duration of diabetes on the outcome of diabetic foot ulcers. Diabetic Medicine. 2001;18(1):133-138.
41. Rick S, Carson RG. Let your feet do the walking: constraints on stability of bipedal coordination. Exp Brain Res. 2001;136(3):407-412.
42. Smith L, Plehwe W, McGill M, Genev N, Yue DK, Turtle JR. Foot bearing pressure in patients with unilateral diabetic foot ulcers. Diabetic Medicine. 1989;6(7):573-575.
43. Smith SL. Attribution of foot bones to sex and population groups. J Forensic Sci. 1997;42 (2):186-195.
44. Strandness DE, Priest RE, Gibbons GE. Combined clinical and pathologic study of diabetic and nondiabetic peripheral arterial disease. Diabetes. 1964;366-371.
45. Veves A, Murray HJ, Young MJ, Boulton AJM. The risk of foot ulceration in diabetic patients with high foot pressure: a prospective study. Diabetologia. 1992;35(7):660-663.
46. Lavery LA, Armstrong DG, Harkless LB. Classification of diabetic foot wounds: the University of Texas San Antonio diabetic wound classification system. Ostomy/Wound Management. 1997;43(2):44-53.
47. Armstrong DG, Lavery LA. Diabetic foot ulcers: prevention, diagnosis and classification. Am Fam Phys. 1998;57(6):1325-1332.
48. Forest A, Edmonds M. S(AD) SAD: certain aspects seem to have been overlooked. The Diabetic Foot. 2000;3(2):5.
49. Armstrong DG, Lavery LA, Harkless LB. Treatment-based classification system for assessment and care of diabetic feet. Ostomy/Wound Management. 1996;86(7):311-316.
50. Macfarlane RM, Jeffcoate WJ. Classification of diabetic foot ulcers: the S(AD) SAD system. The Diabetic Foot. 1999;2(4):123-131.
51. Young M. Comment from journal associate editor: classification vs description. The Diabetic Foot. 2000;3(2):5.
52. Plassmann P, Peters JM. Recording wound care effectiveness. J of Tissue Viability. 2001;12(1):24-28.



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