Changing Perspectives: Offloading a Patient with a Diabetic Foot Ulcer as Opposed to Offloading a Diabetic Foot Ulcer

Abstract

Diabetic foot ulcers (DFU) represent a tremendous burden to healthcare systems. Offloading is one of the key tenants to healing DFU and knee-high irremovable offloading devices are considered the gold standard for offloading DFU. However, the gold standard is rarely utilized in clinical practice. Patients’ limited tolerance for such devices is one of a number of reasons that have been attributed to the lack of use of these devices. The practice of evidence based medicine relies on shared decision making by pairing patients’ values and preferences with the best available evidence. The present case report reviews the process of a patient centered approach to identify the best offloading option for a patient with DFU. In consultation with the patient, a series of modalities were evaluated for offloading two unilateral forefoot DFU. It is suggested that optimizing DFU offloading outcomes at the population level will require concerted efforts to employ the best offloading solution at the individual patient level. Offloading modalities are necessitated to mitigate the physical stress imparted on DFU during the weight bearing activity patients engage in. Success is likely to be maximized by maintaining a mindset of treating individual patients with DFUs as opposed to simply treating DFUs.

Level of evidence:

Level V: Case report

Introduction:

Diabetes is growing in prevalence, affecting 451 million adults worldwide in 2017, and can lead to serious life-threatening complications such as a diabetic foot ulcer (DFU).¹ Within their lifetime 19–34% of people with diabetes will develop a DFU, and unfortunately individuals that incur these wounds have a mortality rate 2.5 times that of individuals with diabetes that have not suffered a DFU.² DFU are also a tremendous fiscal burden. Approximately one-third of the $237 billion spent on direct costs for diabetes in the United States in 2017 were associated with foot care³. In order to prevent some of the more costly complications of DFU such as infection and amputation, it is important to heal DFU as soon as possible. DFUs typically result from the repetitive ground reactive forces imparted on the feet during weight bearing activities.⁴ Offloading devices allow healing to occur by redirecting physical stress away from DFU locations to other areas of the foot and leg.

Current guidelines from the International Working Group on the Diabetic Foot (IWGDF) consider knee-high irremovable devices (total contact casts and non-removable walkers) to be the ‘gold standard’ for offloading a neuropathic forefoot DFU which is not ischemic or infected.⁵ Although removable cast walkers (RCW) have been shown to provide equivalent offloading of wounds as total contact casts (TCC),^6,7 studies have consistently shown RCW to provide poorer healing outcomes.^7,8 The difference in healing was assumed to be due to patients not adherently wearing their RCWs during all weight bearing activity. Accordingly, a later study was able to objectively demonstrate that the level of adherent use of removable offloading devices is positively associated with DFU healing.⁹ The provision of irremovable offloading devices represent an option for clinicians to attempt to ensure patients’ adherence with their offloading devices. However, despite irremovable devices being considered the gold standard, multiple studies have found they are rarely used by practicing clinicians.^10–12 One of the numerous reasons for which clinicians attribute their lack of TCC usage is patients’ limited tolerance.¹⁰ It is worth noting that while prior studies investigating offloading practices amongst care givers heavily emphasized the limited use of first choice irremovable knee-high offloading options,^10–12 current IWGDF guidelines support the use of second and third choice options when higher tiered options are not tolerated.⁵

The strongest predictor of adherence identified within the Crews et al. 2016 study regarding offloading adherence and DFU healing, was participants’ self-reported levels of postural instability.⁹ A separate study investigating reasons for (non-)adherence to self-care in people with DFU also found instability while wearing offloading devices to be a driver of non-adherence.¹³ Some additional factors that likely contribute to patients’ limited tolerance for knee high irremovable offloading devices include their substantial weight and tendency to induce an artificial limb length discrepancy.¹⁴ Patients at risk for DFU have been shown to have better gait parameters and self-reported comfort when using a short RCW (terminating slightly above the ankle) paired with an external shoe lift for their contralateral limb in comparison to a traditional scenario of a knee-high RCW without a contralateral shoe lift.¹⁵ The study from which that finding came was a progression of prior work that found short RCW were able to provide similar offloading to feet as knee high RCW.¹⁶

This article presents a case report in which a patient with a chronic DFU was provided a number of different offloading modalities in an effort to find a solution that would work both for the patient and the DFU. It demonstrates the importance of considering patient preferences and values in addition to what the evidence states in order to achieve the desired clinical result. Such an approach encourages physicians to focus on treating the patient with the DFU rather than just treating the DFU. The patient provided written consent for the authors to publish details regarding the care for his DFU as well as images of the DFU.

Case Report:

A 64-year-old male with well controlled type 2 diabetes mellitus and peripheral neuropathy presented with a Wagner grade 3 ulcer on the plantar aspect of the right hallux and a Wagner grade 2 ulcer on the plantar aspect of the right 1^st metatarsal head. Peripheral neuropathy was assessed using 5.07 Semmes Weinstein Monofilament, measuring 3/10 on the left foot and 4/10 on the right foot. Other patient risk factors included hypertension, hyperlipidemia, 24 year smoking history of 1 pack per week, and living alone in a second floor apartment. The wounds measured 0.7cm × 0.6cm on the hallux and 2.2cm × 2.2cm on the 1^st metatarsal head (Figure 1). The left foot had a recently healed ulcer and was utilizing a post-surgical shoe as a protective measure. He had been receiving treatment for the right foot for the past 5 months with interventions that included weekly sharp debridement with a #15 blade down to bleeding dermal tissue, and debridement using micro waterjet technology (Debritom+, Medaxis AG, Baar Switzerland). He was also given a TCC, according to IWGDF guidelines, as well as an offloading shoe. The TCC although effective for offloading the ulcers, was troublesome for the patient who stated it was difficult to walk up and down his stairs and that the surface of the cast was slippery when he was not compliant with wearing his cast shoe. Therefore, use of the TCC had been discontinued several months prior at the insistence of the patient.

Figure 1.

Diabetic foot ulcers at hallux and 1^st metatarsal

Note: Image A depicts wounds at day 0 and image B depicts wounds at day 56.

At day 0 of this case report, a knee high RCW (Figure 2) was fitted and dispensed for the right foot. Such a device is considered a ‘second choice’ option for offloading DFU according to current guidelines¹⁷. The patient was advised to wear it all times while ambulating. A week later he returned and stated he compliantly wore the RCW for a few days but reported poor balance in the RCW and expressed that he almost hurt himself “really badly.” He stated he fell 3 times while wearing the RCW for just 4 days. When asked how he felt wearing the boot and why he felt unbalanced he said, “I felt shaky and unstable from the get go, I’d have to say the overall way it made me feel, I just felt uneasy.” Despite his unsteadiness the patient did recognize advantages to the knee-high RWC saying, “I mean I guess it’s a pro if my wounds didn’t worsen, I have to say it stabilized my wounds. They didn’t get worse, lately I have a wound on the ball of my foot and the tip of my big toe, I’ve been going back and forth for almost a month, and now they are both improved.” One week after being dispensed the knee high RCW his right hallux DFU measured 0.7cm × 0.6cm and his right 1^st metatarsal head DFU measured 1.8cm × 1.8cm. Despite improvements, he stated that due to his fear of falling and hurting himself he “(wouldn’t) ever wear the tall one again.” Due to his resistance to RCW following his use of the knee-high device, he was put into a football dressing or soft contact cast. Such a dressing consists of wrapping the foot in cast padding followed by gauze and a final layer of self-adherent wrap.^18,19 Once applied the foot resembles the shape of an American football. Soft contact casts are not well represented in the literature and subsequently are not referenced in current offloading guidelines.⁵ On day 21 after two weeks of soft contact cast use, he assented to be fitted for the higher level of evidence offloading modality of a short RCW.

Figure 2.

Offloading modalities and wound healing progression

Note: Color of contralateral lift has been altered from black to blue in order to increase contrast between the lift and the black surgical shoe to which it is attached. DFU surface area calculated as length × width of the wound.

A short RCW would be considered a third choice option under current offloading guidelines.¹⁷ To help improve his balance while wearing the short RCW on his right limb and the post-surgical shoe on his left limb, a prefabricated external shoe lift was placed on the post-surgical shoe on day 42. When the patient returned to the clinic he reported that he did not do a lot of walking with the shoe lift, because he had trouble keeping it on. When asked if he felt balanced with the shoe lift on the surgical shoe on the left foot, and the short RCW on the right foot he stated, “Oh yeah definitely, as soon as I walked I said wow, I feel like I could almost go dancing in this. The first thing I noticed when I stood up I’m walking on, I’m on an even keel with this, I felt perfectly even.” The patient then discussed how if he could return to his therapeutic (diabetic) shoe on his left foot, he would continue to use the shoe lift. He stated, “If I wasn’t wearing a post-surgical shoe and was able to wear a tennis shoe I would wear it.” At the conclusion of his visit he voiced approval of the shoe lift stating, “the technology, the thinking behind it is excellent, but it just didn’t work for my mode of footwear.” Due to the perceived problematic interface of the external shoe lift with the surgical shoe, the patient discontinued use of the lift while he remained in the surgical shoe.

Discussion:

When the concept of evidence-based medicine (EBM) was first introduced its focus was on educating clinicians to utilize published literature to optimize clinical care, however, as EBM evolved there was a recognition in the limitations of relying on evidence alone when making care decisions.²⁰ As EBM has progressed, it has “increasingly stressed the need to combine critical appraisal of the evidence with patient’s values and preferences through shared decision making” (p. 415). Based on currently available offloading evidence, the best healing outcomes for plantar neuropathic DFU without moderate ischemia or infection are achieved with the use of knee-high irremovable devices.⁵ Although the limited use of irremovable offloading devices by caregivers in practice has been attributed to a number of factors (e.g. costs, familiarity with methods, clinician coverage, lack of wound access for dressing changes) one of the most common reasons is patient intolerance.^10–12 This case report of a DFU patient presents the process of identifying the best offloading option that would be accepted by the patient.

The patient had a history of prior TCC use and refused to use a TCC again. He agreed to try a knee-high RCW, however, after several falls in the first week of use he refused to continue using the device. Falls are a significant challenge in persons with diabetes and RCW may further challenge balance due to their utilization of rocker bottom soles, restriction of ankle motion, imposition of limb length discrepancies and substantial weight.^14,21 This case study suggests providers should take into consideration individual patients’ mobility limitations when recommending offloading devices. This may lead to more in-depth conversations with patients about what they should expect while using a particular offloading device, more thorough assessment of functional capacity at the time an offloading device is dispensed and in some cases it may present justification for selecting a lower tiered offloading choice from established recommendations.

Following the discontinuation of the knee-high RCW, this case study’s patient used a soft contact cast for two weeks before agreeing to use a short RCW (extending to a height slightly above the ankle). The patient found the short RCW acceptable and wore it throughout the remaining duration of this case report. The improved stability relative to the knee-high RCW may have been due to the short RCW affording greater range of motion at the ankle joint and its reduced weight. The external shoe lift that was provided for use with the contralateral limb was perceived to be beneficial by the patient, however, he found it to be somewhat incompatible with the surgical shoe he was wearing at the time. Thus he discontinued use of the lift while continuing to use the surgical shoe with his recently healed left foot.

Although the body of literature surrounding the use of short RCW is smaller than that for knee-high RCW, a pair of clinical trials have yielded promising results. One trial randomized forty-five participants to either a TCC or a short RCW and found no difference in reduction of DFU size or the number of patients that achieved complete closure of the wound.²² The second study compared outcomes in patients treated with either a TCC, short RCW rendered irremovable or a short RCW.²³ Similar to the first study, the second found no between group differences in wound healing outcomes.

The authors acknowledge the limitations of this study, including that this is a single case study. A larger case series may provide more robust and confirmatory results. Also, adherence in the present case study was measured through patient self-reporting, which may not be reliable. There is much room for future research in regards to shared decision making with respect to offloading DFU, including studies that use a validated questionnaire to evaluate patients’ responses to treatment options.

Conclusion:

DFU offloading guidelines have a progression of recommended options based on currently available literature.⁵ Unfortunately, the preferred first choice of knee-high irremovable devices are frequently not tolerated by patients.^10–12 This case report presents the process of working with a DFU patient in order to identify the best offloading option from the perspective of both the DFU itself and the patient with the DFU. It may be possible to make inroads in reducing the tremendous burden imposed by slow healing DFU by making concerted efforts to employ the best offloading solution for each individual patient. Such an approach to active DFU is somewhat akin to the recently proposed shift towards personalized medicine for the prevention of DFU.²⁴

The need for offloading devices arises from the necessity to mitigate the physical stress imparted on DFU during the weight bearing activity patients consciously engage in. Success is likely to be maximized by maintaining a mindset of treating individual patients with DFUs as opposed to simply treating DFUs. Frank two-way discussions regarding the evidence available on varied offloading options and patients’ individual concerns that lead to shared decision making, may result in the best patient outcomes.