Preparation for WOCNCB foot care certification requires a thorough understanding of calluses, including causes, complications, and treatment. In 82% of clients who develop a foot ulcer, the initial cause is callus formation.1
Callus formation is related to pressure and plantar shear stress during the push-off phase of walking.1 In clients with diabetes-related peripheral neuropathy, force or pressure can further contribute to diabetic foot ulcerations.2 In addition to pressure and stress from walking, causes of callus formation with a client who has diabetic neuropathy may include bone deformity, limited joint mobility, and ill-fitting shoes.3 The risk for developing a diabetic foot ulcer (DFU) is higher in patients who have Charcot's foot. Understanding that callus formation will likely lead to ulcer formation is paramount, with 40% of individuals who heal developing another ulcer within 12 months and 60% within 3 years.4
Diabetic foot ulcer infection is another complication that may occur, and prevention of systemic infection is crucial. Standing, walking, or any other activity that may compress tissue must be managed, as it can exacerbate a localized infection and lead to a more widespread or systemic infection.2 An off-loading device is the primary intervention to protect this tissue. When selecting any off-loading device in the setting of active infection, clinicians should consider a removable option to allow for frequent visual inspection.
Determining the cause of force (shearing, compressive, frictional, tensile) is essential in the prevention and management of foot ulcers. Shearing force occurs when tissue is moving in 2 or more different directions.2 Tissue that is squeezed between 2 or more opposing loads experiences compressive force.2 A force that moves over a surface while maintaining contact is frictional force.2 Tensile force occurs when tissue is stretched by 2 or more opposing forces.2 Fundamental principles of management of pressure ulcers or injuries include off-loading to reduce the excessive or sustained forces to injury-prone areas.2
The location of the ulcer in the rear, mid-, or forefoot can impact the effectiveness of off-loading interventions and should be considered by the CFCN when determining best long-term treatment options. Toe ulcers are more difficult to treat and can be related to small shoe toe box and require proper shoe sizing or removal of the area causing friction. Therapeutic footwear has been shown to reduce the risk of initial and recurring ulcerations. Therapeutic rocker sole shoes have been associated with avoiding future complications because of their high toe box, wide heel, and specialty laces.5
Off-loading of plantar wounds is essential in managing DFUs, as delayed wound healing has been identified in up to 94% of plantar foot ulcers.5 Crutches, rolling walkers, and wheelchairs are simple and effective methods for off-loading areas of potential ulcers but may not always be practical. A removable cast walker (RCW) is commonly used for the management of DFUs due to time and skill constraints of the clinician with application.6 Total contact casts are the gold standard treatment of mid- and forefoot lesions as they reduce stride length and redistribute plantar forces.5 They are also associated with higher ulcer healing rates compared to the RCW.7 Off-loading recommendations from the International Working Group on the Diabetic Foot Guidelines note a nonremovable knee-high off-loading device as the first choice of off-loading treatment. This is followed by a removable knee-high device and then a removable ankle-high off-loading device as second- and third-choice off-loading treatments.8 If patient presentation prevents use of these options, properly fitted footwear combined with felted foam can be considered as a fourth choice. For patients with metatarsal head and digital ulcers, surgical off-loading interventions should be considered by referral to a surgeon.9
WOCNCB-certified foot care nurses (CFCN) play a critical role in the prevention and treatment of DFUs through their role in holistic patient management of calluses and off-loading. Nurses preparing for WOCNCB foot care certification should be mindful of psychological factors that impact quality of life along with adherence to treatment plans when determining the best off-loading option. Clients with a DFU may experience ulcer-specific emotional distress combined with required use of off-loading devices that may limit healing or impact preventive foot self-care.6
1. Amemiya A, Noguchi H, Oe M, et al Factors associated with callus formation in the plantar region through gait measurement in patients with diabetic neuropathy: an observational case-control study. Sensors. 2020;20(17):4863. doi:10.3390/s20174863. [Context Link]
2. Baker N, Osman I. The principles and practicalities of offloading diabetic foot ulcers. Diabetic Foot J. 2016;19:172-181. [Context Link]
3. Hamatani M, Mori T, Oe M, et al Factors associated with callus in patients with diabetes, focused on plantar shear stress during gait. J Diabetes Sci Technol. 2016;10(6):1353-1359. doi:10.1177/1932296816648164. [Context Link]
4. Aan de Stegge WB, Schut MC, Abu-Hanna A, et al Development of a prediction model for foot ulcer recurrence in people with diabetes using easy-to-obtain clinical variables. BMJ Open Diabetes Res Care. 2021;9(1):e002257. doi:10.1136/bmjdrc-2021-002257. [Context Link]
5. Bhatt UK, Foo HY, McEvoy MP, et al Is TCC-EZ a suitable alternative to gold standard total-contact casting? A plantar pressure analysis. J Am Podiatr Med Assoc. 2021;111(5). doi:10.7547/8750-7315-111-5.Article_1. [Context Link]
6. Crews RT, Shen BJ, Campbell L, et al Role and determinants of adherence to off-loading in diabetic foot ulcer healing: a prospective investigation. Diabetes Care. 2016;39(8):1371-1377. doi:10.2337/dc15-2373. [Context Link]
7. Okoli GN, Rabbani R, Lam OLT, et al Offloading devices for neuropathic foot ulcers in adult persons with type 1 or type 2 diabetes: a rapid review with meta-analysis and trial sequential analysis of randomized controlled trials. BMJ Open Diabetes Res Care. 2022;10(3):e002822. doi:10.1136/bmjdrc-2022-002822. [Context Link]
8. Bus SA, Armstrong DG, Gooday C, et al Guidelines on offloading foot ulcers in persons with diabetes (IWGDF 2019 update). Diabetes Metab Res Rev. 2020;36(suppl 1):e3274. doi:10.1002/dmrr.3274. [Context Link]
9. Bus SA. The role of pressure offloading on diabetic foot ulcer healing and prevention of recurrence. Plast Reconstr Surg. 2016;1383(suppl):179S-187S. doi:10.1097/PRS.0000000000002686. [Context Link]
CFCN PRACTICE QUESTIONS
1. A CFCN has undergone additional education and training in conservative sharp wound debridement (CSWD) and is approved to provide this service by the state nurse practice act and the practice facility. A patient presents with a painful neuropathic ulcer on the left plantar midfoot. What patient response to wound debridement could indicate the nurse has gone beyond CSWD?
A. Bleeding
B. Pain
C. Debriding exposed structures
D. All of the above
Cognitive level: Analysis
Exam content outline location: 020305
ANSWER: D
Rationale: Conservative sharp wound debridement is a key intervention in chronic wound care and entails the removal of loose, devascularized tissue, callus, or hyperkeratotic tissue using a scalpel, scissors, or curette.1 Surgical sharp debridement is a more aggressive means of tissue removal that often involves removing viable and nonviable tissues.2 Core differences between CSWD and surgical or sharp wound debridement include the principle that CSWD is not intended to cause pain, bleeding, or the debridement of exposed structures such as bone, tendon, vascular structures, or ligaments, making all above-listed answer options the correct answer.2
1. Rodd-Nielsen E, Harris CL. Conservative sharp wound debridement: an overview of Canadian education, practice, risk, and policy. J Wound Ostomy Continence Nurs. 2013;40(6):594-601. doi:10.1097/WON.0b013e3182a9ae8c. [Context Link]
2. Rodd-Nielsen E, Brown J, Brooke J, et al Canadian Association for Enterostomal Therapy evidence-based recommendations for conservative sharp wound debridement: an executive summary. J Wound Ostomy Continence Nurs. 2013;40(3):246-253. doi:10.1097/WON.0b013e31828fd3fc. [Context Link]
2. A middle-aged client with a history of diabetic neuropathy is being followed for a newly healed DFU on the left plantar surface. Which of the following off-loading methods is the best option for the CFCN to select for preventing further callus formation?
A. Using rocker sole footwear
B. Using a rolling walker
C. Reinforcing gait training
D. Maintaining bed rest until ulcer healing
Cognitive level: Application
Exam content outline location: 020503
ANSWER: A
Rationale: Therapeutic footwear offers protection in reducing the risk for re-ulceration. Shoes with a rocker sole can reduce plantar pressure and will decrease DFU recurrence.1 Rocker sole footwear may specifically improve push-off motion to prevent callus formation because such footwear increases the motion of the lower limbs.2 The use of a rolling walker is easy but not practical. While gait training will be beneficial for balance, this will not provide adequate off-loading to prevent further callus formation. Mobility should be encouraged for those who are ambulatory; staying in bed until the ulcer is healed is not appropriate.
1. Lopez-Moral M, Lazaro-Martinez JL, Garcia-Morales E, Garcia-Alvarez Y, Alvaro-Afonso FJ, Molines-Barroso RJ. Clinical efficacy of therapeutic footwear with a rigid rocker sole in the prevention of recurrence in patients with diabetes mellitus and diabetic polineuropathy: a randomized clinical trial. PLoS One. 2019;14(7):e0219537. doi:10.1371/journal.pone.0219537. [Context Link]
2. Crews RT, Shen BJ, Campbell L, et al Role and determinants of adherence to off-loading in diabetic foot ulcer healing: a prospective investigation. Diabetes Care. 2016;39(8):1371-1377. doi:10.2337/dc15-2373. [Context Link]
3. A CFCN is providing in-home routine foot care for an elderly ambulatory client. The client complains of increased pain in the lateral aspect of the fifth metatarsal joint. Upon assessment, the CFCN notes an area of erythema. Which action should the CFCN should take next?
A. Suggest an RCW
B. Complete pressure mapping study
C. Assess the client's footwear
D. Provide cushion to the noted area
Cognitive level: Application
Exam content outline location: 020507
ANSWER: C
Rationale: The friction is likely caused by an incorrectly sized toe box.1 The best approach would be to obtain shoes that have a larger shoe box or with permission remove the area of friction.1 As the client does not have a current ulcer, an RCW would not be the first line of treatment. Pressure mapping can provide helpful information focusing on plantar pressure distribution, gait, and postural imbalance conditions for diagnosing a lower-limb problem.2 Adding additional cushion may increase friction or shear to the area. However, the shoe should be assessed first.
1. Baker N, Osman I. The principles and practicalities of offloading diabetic foot ulcers. Diabetic Foot J. 2016;19:172-181. [Context Link]
2. Beurscher T. Foot and nail care. In: McNichol LL, Ratliff CR, Yates SS, eds. Wound, Ostomy, and Continence Nurses Society Core Curriculum Wound Management. Philadelphia, PA: Wolters Kluwer; 2022:603-627. [Context Link]