Offloading of diabetes‐related neuropathic foot ulcers at Swedish prosthetic and orthotic clinics

This study aimed to assess (1) the use of different offloading interventions in Sweden for the healing of diabetes‐related plantar neuropathic forefoot ulcers, (2) factors influencing the offloading intervention choice, and (3) the awareness of current gold standard offloading devices.


| INTRODUCTION
Diabetes-related foot ulcers (DFUs) affect 19%-34% of persons with diabetes during their lifetime 1 and precede 50% of lower-limb amputations in Sweden. 2 Excessive repetitive mechanical trauma, increased peak pressure, and shear stress on the feet in combination with peripheral neuropathy commonly cause DFUs on the plantar surface. 3 DFUs are associated with premature death and lead to a cascade of negative effects for the affected persons, with an impact on their quality of life and accumulated costs for the health care systems. [4][5][6][7][8] However, there is evidence that multidisciplinary treatment, including offloading interventions that redistribute plantar pressure, is effective in shortening healing time. 3 The International Working Group on the Diabetic Foot (IWGDF) 3 recommends that a total contact cast (TCC) and nonremovable knee-high walkers be used as the gold standard treatments for plantar neuropathic forefoot DFUs that are not affected by severe ischaemia and infection.
Removable knee-high offloading devices and ankle-high offloading devices are recommended as second-and third-choice treatments.
The fourth recommendation by IWGDF is that if none of the abovementioned devices are available or all of them are contraindicated, the use of felted foam in combination with appropriate footwear should be provided.
There is a gap between clinical practice when clinicians select offloading interventions for the treatment of DFUs and the IWGDF recommendations, which are based on scientific evidence. [9][10][11] Studies in Europe, the USA and Australia have shown that practitioners underutilise nonremovable knee-high devices, [9][10][11] although the majority of them agree that these devices are the gold standard treatment. 9,10 To our knowledge, no study has presented the type and frequencies of offloading interventions that practitioners provide to patients with plantar forefoot DFUs in Sweden, which may differ compared to other countries depending on differences in culture, reimbursement systems, etc. Furthermore, there is a lack of studies that investigate the factors that practitioners consider important when selecting offloading interventions to heal plantar forefoot DFUs.

| AIM
This study aimed to assess (1) the use of different offloading interventions in Sweden for healing plantar neuropathic forefoot DFUs, (2)

| Study design
The study was an observational cross-sectional study that collected answers from a quantitative survey.

| Questionnaire and pilot testing
A questionnaire developed and used by Raspovic and Landorf in an Australian study 9 was translated into Swedish with the authors' approval. Six out of 12 questions (questions 1 and 4-8) were selected from the original questionnaire. Question number 8, originally concerning whether practitioners considered nonremovable offloading to be the gold standard in offloading, was separated into two questions concerning whether TCC and a nonremovable kneehigh walker, respectively, were considered the gold standard in offloading. The original English questionnaire was translated into Swedish based on the recommendations of the World Health Organization. 13 First, the first authors (IG and EDS) translated the questionnaire from English to Swedish. An expert panel including a In question 1, the practitioners were asked to specify the percentage of patients for whom 14 predefined offloading interventions were used. The practitioners were free to add additional interventions or combinations of interventions. In questions 2-5, the practitioners were asked to rank on a 5-point Likert scale (from 0 = never to 4 = always) how often 28 predefined practitioner-, patient-, intervention-, and wound-related factors were considered in the provision of offloading interventions. In questions 6-7, the practitioners were asked if TCC or a nonremovable knee-high walker was considered the gold standard offloading device.

| Participants and procedure
An e-mail invitation was sent to 39 operational managers of 51 P&O clinics from all 21 regions in Sweden. The invitation included study information and a link to the questionnaire. The operational managers were asked to share the electronic questionnaire with a practitioner who fulfiled the inclusion criterion of having at least 12 months' of experience providing offloading interventions to patients with DFUs.
Two follow-up emails, including a reminder to participate, were sent to the operational managers 7 and 11 days after the initial e-mail. The participating practitioners gave informed consent to participate by checking a box in the electronic questionnaire. According to Swedish law, no ethical approval for the study was needed because the study did not entail any physical intervention, did not affect the participants in any physical or psychological manner, and did not collect personal data or data about the participants' criminal offences.

| Statistical analysis
The data were exported from SurveyMonkey into International Business Machines Corporation (IBM) Statistical Package for the Social Sciences version 27.0 (Armonk, NY: IBM Corp; 2020). Descriptive statistics were calculated for all questions. Spearman's correlation coefficient was calculated to estimate the correlation between the two questions on the practitioners' awareness of gold standard offloading devices (TCC and nonremovable knee-high walker).

| RESULTS
A total of 35 out of 51 practitioners answered the questionnaire, yielding a response rate of 69%.

| Use of offloading interventions
In addition to the 14 predefined devices, the practitioners reported using six other offloading interventions or combinations of offloading interventions (Table 1). Modified off-the-shelf footwear with insoles was provided by 86% of the practitioners (to a mean of 59% of patients) and modified off-the-shelf footwear without insoles was provided by 49% of the practitioners (to 30% of patients). Postoperative shoes, categorised as ankle-high interventions, were provided by 71% of the practitioners (to 12% of patients). Removable knee-high walkers and removable casts were provided by 49% of the practitioners (to 9% of patients), and 20% of the practitioners provided TCCs (to 8% of patients). No practitioner provided offloading wound dressings or nonremovable knee-high walkers.

| Factors considered in the provision of offloading interventions
The median ranking of "often" was registered for 14 of the 28 factors that practitioners considered when providing a patient with an offloading intervention ( Table 2). Wound-related factors were considered "often" or "always". Patient-and practitioner-related factors were considered "sometimes" or "often". Intervention-related factors showed a more heterogeneous pattern where secondary complications, patient tolerance, and gait instability were "often" considered, medical backup and bulkiness/weight were "sometimes" considered, and cost, appearance, and time to apply the intervention were "seldom" considered.

| Awareness of gold standard offloading devices
On the question about whether practitioners considered TCC to be the gold standard treatment, 26% answered yes, 37% were unsure and 37% answered no ( Table 3). The average percentage of patients GIGANTE ET AL. provided with TCC among the answers (yes, no, unsure) ranged from 0% to 3% (Table 3). On the question of whether practitioners considered nonremovable knee-high walkers to be the gold standard treatment, 26% answered yes, 23% were unsure, and 51% answered no ( Table 3). None of the practitioners provided nonremovable kneehigh walkers (Table 3). Spearman's correlation coefficient between the answers to the two questions on the awareness of gold standard offloading devices was 0.812 (p < 0.001; Table 4). Thus, practitioners who agreed that TCC is the gold standard for offloading also tended to agree that a nonremovable knee-high walker was the gold standard for offloading.

| DISCUSSION
The practitioners provided a great variety of offloading interventions to treat plantar neuropathic forefoot DFUs. They mainly provided modified off-the-shelf footwear with insoles, while TCCs and nonremovable knee-high walkers were highly underutilised. Practitioners most often considered wound-related factors in the selection of interventions but also considered practitioner-, patient-and intervention-related factors. The majority of the practitioners were unaware or unsure of the current gold standard devices for neuropathic forefoot DFUs.
The international IWGDF guidelines recommend nonremovable knee-high devices (TCCs or nonremovable knee-high walkers) as the first-choice offloading treatment, removable knee-high devices (removable casts or walkers) as the second choice, removable anklehigh devices as the third choice, and footwear combined with felted foam as the fourth-choice treatment. 3 The IWGDF recommends against using footwear to heal plantar forefoot DFUs unless none of the aforementioned, more effective, offloading devices are available.
However, as all of these more effective devices are available in Sweden, footwear should not be used for healing plantar forefoot lower priority to the use of shoes, insoles or removable orthoses. 14 In the current study, only 20% and 0% of the study practitioners provided TCCs and nonremovable walkers, respectively, 49% provided removable casts or knee-high walkers, 71% provided a removable ankle-high device and no practitioner-provided footwear in combination with felted foam. Furthermore, 86% of the practitioners provided footwear that the IWGDF recommends against T A B L E 2 Frequencies of practitioner-, patient-, intervention-, and wound-related factors taken into consideration when P&O practitioners provide offloading interventions to treat plantar neuropathic forefoot ulcers in patients with diabetes. Whether an intervention will be tolerated 3 (3-4) 3.2 (0.7) 2-4

Median (quartile 1-3) Mean (SD) Min to max
How long an intervention will take to apply 1 (1-2) 1.5 (1.0) 0-4 Whether an intervention will cause gait instability 3 (2-4) 3.0 (0.9) 1-4 Wound-related factors In the Eurodiale study, which included 14 diabetic foot centres in 10 European countries, the centres provided TCCs to an average of 18% of patients with plantar fore-or midfoot DFUs. 11  The results of the current study and the study by Raspovic and Landrof 9 indicate that the choice of offloading intervention is a complex process and that several factors and barriers need to be considered. Notably, compared to the Swedish P&O practitioners, the Australian podiatrists considered to a higher degree whether the suggested offloading intervention would restrict wound care.
This factor is relevant only if a nonremovable device is used.
Because nonremovable devices were underutilised by P&O practitioners in Sweden, this factor was naturally less important. In the present study, a gap was found between the offloading interventions prescribed and the interventions recommended in guidelines, 3,14 a pattern that has been observed in other studies. [9][10][11] This gap between recommendations and practice may partly be because many DFU offloading studies on which the guidelines are based have a narrower perspective than the perspective of practitioners. That is, practitioners tend to consider more factors when choosing offloading devices, such as practitioner-and patientrelated factors, than those considered in studies on these devices.
Thus, future studies need to take a broader perspective on offloading, including patients' tolerance and preferences as well as the impact on gait and daily activities, to better reflect the clinical situation of patients.
There was a strong correlation between the answers (yes, no, unsure) to the two questions regarding awareness of the gold standard offloading treatments, meaning that practitioners who considered TCC the gold standard treatment also considered nonremovable T A B L E 3 Knowledge and provision of gold standard offloading devices.

Practitioners considering TCC the gold standard, % (n)
knee-high walkers to be the gold standard treatment. However, overall, the awareness of the gold standard of offloading was low; only 23% of the practitioners were aware that both TCC and nonremovable knee-high walkers are gold standard treatments for plantar forefoot DFUs compared to 83% of podiatrists in Australia 9 and 41.9% of centres treating DFUs in the USA. 10 Despite this low awareness among the practitioners in the current study and although they provided interventions almost opposite to the guidelines, the practitioners reported that they "often" considered evidence-based practice when prescribing offloading interventions. The reasons for this discrepancy among practitioners need to be further investigated to increase the use of the recommended offloading interventions.