Differences in the daily activity of patients with diabetic foot ulcers compared to controls in their free-living environments

Effectiveness of offloading interventions for people with diabetes-related foot ulcers: A systematic review and meta-analysis

BACKGROUND

Offloading treatment is crucial to heal diabetes-related foot ulcers (DFU). This systematic review aimed to assess the effectiveness of offloading interventions for people with DFU.

METHODS

We searched PubMed, EMBASE, Cochrane databases, and trials registries for all studies relating to offloading interventions in people with DFU to address 14 clinical question comparisons. Outcomes included ulcers healed, plantar pressure, weight-bearing activity, adherence, new lesions, falls, infections, amputations, quality of life, costs, cost-effectiveness, balance, and sustained healing. Included controlled studies were independently assessed for risk of bias and had key data extracted. Meta-analyses were performed when outcome data from studies could be pooled. Evidence statements were developed using the GRADE approach when outcome data existed.

RESULTS

From 19,923 studies screened, 194 eligible studies were identified (47 controlled, 147 non-controlled), 35 meta-analyses performed, and 128 evidence statements developed. We found non-removable offloading devices likely increase ulcers healed compared to removable offloading devices (risk ratio [RR] 1.24, 95% CI 1.09-1.41; N = 14, n = 1083), and may increase adherence, cost-effectiveness and decrease infections, but may increase new lesions. Removable knee-high offloading devices may make little difference to ulcers healed compared to removable ankle-high offloading devices (RR 1.00, 0.86-1.16; N = 6, n = 439), but may decrease plantar pressure and adherence. Any offloading device may increase ulcers healed (RR 1.39, 0.89-2.18; N = 5, n = 235) and cost-effectiveness compared to therapeutic footwear and may decrease plantar pressure and infections. Digital flexor tenotomies with offloading devices likely increase ulcers healed (RR 2.43, 1.05-5.59; N = 1, n = 16) and sustained healing compared to devices alone, and may decrease plantar pressure and infections, but may increase new transfer lesions. Achilles tendon lengthening with offloading devices likely increase ulcers healed (RR 1.10, 0.97-1.27; N = 1, n = 64) and sustained healing compared to devices alone, but likely increase new heel ulcers.

CONCLUSIONS

Non-removable offloading devices are likely superior to all other offloading interventions to heal most plantar DFU. Digital flexor tenotomies and Achilles tendon lengthening in combination with offloading devices are likely superior for some specific plantar DFU locations. Otherwise, any offloading device is probably superior to therapeutic footwear and other non-surgical offloading interventions to heal most plantar DFU. However, all these interventions have low-to-moderate certainty of evidence supporting their outcomes and more high-quality trials are needed to improve our certainty for the effectiveness of most offloading interventions.

Habitual Physical Activity of People with or at Risk of Diabetes-Related Foot Complications

Regular physical activity is an important component of diabetes management. However, there are limited data on the habitual physical activity of people with or at risk of diabetes-related foot complications. The aim of this study was to describe the habitual physical activity of people with or at risk of diabetes-related foot complications in regional Australia. Twenty-three participants with diabetes from regional Australia were recruited with twenty-two participants included in subsequent analyses: no history of ulcer (N = 11) and history of ulcer (N = 11). Each participant wore a triaxial accelerometer (GT3X+; ActiGraph LLC, Pensacola, FL, USA) on their non-dominant wrist for 14 days. There were no significant differences between groups according to both participant characteristics and physical activity outcomes. Median minutes per day of moderate-to-vigorous physical activity (MVPA) were 9.7 (IQR: 1.6-15.7) while participants recorded an average of 280 ± 78 min of low-intensity physical activity and 689 ± 114 min of sedentary behaviour. The sample accumulated on average 30 min of slow walking and 2 min of fast walking per day, respectively. Overall, participants spent very little time performing MVPA and were largely sedentary. It is important that strategies are put in place for people with or at risk of diabetes-related foot complications in order that they increase their physical activity significantly in accordance with established guidelines.

Rate of tarsal and metatarsal bone mineral density change in adults with diabetes mellitus and peripheral neuropathy: a longitudinal study

BACKGROUND

In people with diabetes (DM) and peripheral neuropathy (PN), loss of bone mineral density (BMD) in the tarsals and metatarsals contribute to foot complications; however, changes in BMD of the calcaneal bone is most commonly reported. This study reports rate of change in BMD of all the individual bones in the foot, in participants with DM and PN. Our aim was to investigate whether the rate of BMD change is similar across all the bones of the foot.

METHODS

Participants with DM and PN (n = 60) were included in this longitudinal cohort study. Rate of BMD change of individual bones was monitored using computed tomography at baseline and 6 months, 18 months, and 3-4 years from baseline. Personal factors (age, sex, medication use, step count, sedentary time, and PN severity) were assessed. A random coefficient model estimated rate of change of BMD in all bones and Pearson correlation tested relationships between personal factor variables and rate of BMD change.

RESULTS

Mean and calcaneal BMD decreased over the study period (p < 0.05). Individual tarsal and metatarsal bones present a range of rate of BMD change (-0.3 to -0.9%/year) but were not significantly different than calcaneal BMD change. Only age showed significant correlation with BMD and rate of BMD change.

CONCLUSION

The rate of BMD change did not significantly differ across different foot bones at the group level in people with DM and PN without foot deformity. Asymmetric BMD loss between individual bones of the foot and aging may be indicators of pathologic changes and require further investigation.

TRIAL REGISTRATION

Metatarsal Phalangeal Joint Deformity Progression-R01. Registered 25 November 2015, https://clinicaltrials.gov/ct2/show/NCT02616263.

Personalized Offloading Treatments for Healing Plantar Diabetic Foot Ulcers

BACKGROUND

Non-removable knee-high devices are the gold-standard offloading treatments to heal plantar diabetic foot ulcers (DFUs). These devices are underused in practice for a variety of reasons. Recommending these devices for all patients, regardless of their circumstances and preferences influencing their ability to tolerate the devices, does not seem a fruitful approach.

PURPOSE

The aim of this article is to explore the potential implications of a more personalized approach to offloading DFUs and suggest avenues for future research and development.

METHODS

Non-removable knee-high devices effectively heal plantar DFUs by reducing plantar pressure and shear at the DFU, reducing weight-bearing activity and enforcing high adherence. We propose that future offloading devices should be developed that aim to optimize these mechanisms according to each individual's needs. We suggest three different approaches may be developed to achieve such personalized offloading treatment. First, we suggest modular devices, where different mechanical features (rocker-bottom sole, knee-high cast walls/struts, etc.) can be added or removed from the device to accommodate different patients' needs and the evolving needs of the patient throughout the treatment period. Second, advanced manufacturing techniques and novel materials could be used to personalize the design of their devices, thereby improving common hindrances to their use, such as devices being heavy, bulky, and hot. Third, sensors could be used to provide real-time feedback to patients and clinicians on plantar pressures, shear, weight-bearing activity, and adherence.

CONCLUSIONS

By the use of these approaches, we could provide patients with personalized devices to optimize plantar tissue stress, thereby improving clinical outcomes.

Weight-bearing physical activity in people with diabetes-related foot disease: A systematic review

INTRODUCTION

Weight-bearing physical activity is important for people with diabetes-related foot disease but may also contribute to ulceration or delayed ulcer healing. No overview of weight-bearing activity of people at different stages of foot disease is available. We aimed to summarise quantitatively measured daily activity levels in people with diabetes-related foot disease.

METHODS

We systematically searched peer-reviewed literature for studies reporting objectively measured weight-bearing activity in people with diabetes-related foot disease. We calculated daily step counts' means (over studies) and weighted means (over participants). International Working Group on the Diabetic Foot (IWGDF) risk strata, different climates, and activity indoors versus outdoors were compared.

RESULTS

From 1247 publications, 27 were included. Mean steps/day in people with IWGDF risk 1/2: 6125 (12 studies; 345 participants; weighted mean: 5384). In IWGDF risk 3: 6167 (8 studies; 291 participants; weighted mean: 6239). In those with a foot ulcer: 4248 (6 studies; 186 participants; weighted mean: 4484). People living in temperate oceanic climates are more active compared to those in hotter or more humid climates (mean steps/day for no ulcer: 7712 vs. 5224 [18 studies]; for ulcer: 6819 vs. 2945 [6 studies]). People are more active indoors than outdoors (mean 4047 vs. 2514 [3 studies]).

CONCLUSION

Levels of weight-bearing physical activity are similar between people with diabetes at various risk levels for foot ulceration but lower for those with a foot ulcer. Weight-bearing activity differs depending on the climatological environment and is higher indoors than outdoors. These findings provide reference for intervention studies or for clinicians aiming to provide mobility advice in this population.

An Enzymatic Multiplexed Impedimetric Sensor Based on α-MnO2/GQD Nano-Composite for the Detection of Diabetes and Diabetic Foot Ulcer Using Micro-Fluidic Platform

Diabetes is widely considered as a silent killer which affects the internal organs and ultimately has drastic impacts on our day-to-day activities. One of the fatal outcomes of diabetes is diabetic foot ulcer (DFU); which, when becomes chronic, may lead to amputation. The incorporation of nanotechnology in developing bio-sensors enables the detection of desired biomarkers, which in our study are glucose and L-tyrosine; which gets elevated in patients suffering from diabetes and DFUs, respectively. Herein, we report the development of an enzymatic impedimetric sensor for the multi-detection of these biomarkers using an electrochemical paper-based analytical device (µ-EPADs). The structure consists of two working electrodes and a counter electrode. One working electrode is modified with α-MnO2-GQD/tyrosinase hybrid to aid L-tyrosine detection, while the other electrode is coated with α-MnO2-GQD/glucose oxidase hybrid for glucose monitoring. Electrochemical impedance spectroscopy has been employed for the quantification of glucose and L-tyrosine, within a concentration range of 50–800 mg/dL and 1–500 µmol/L, respectively, using a sample volume of approximately 200 µL. The impedance response exhibited a linear relationship over the analyte concentration range with detection limits of ~58 mg/dL and ~0.3 µmol/L for glucose and tyrosine respectively, with shelf life ~1 month. The sensing strategy was also translated to Arduino-based device applications by interfacing the µ-EPADs with miniaturized electronics.

Dosing Activity and Return to Preulcer Function in Diabetes-Related Foot Ulcer Remission

Diabetes-related foot ulcers are a leading cause of global morbidity, mortality, and health-care costs. People with a history of foot ulcers have a diminished quality of life attributed to limited walking and mobility. One of the largest concerns is ulceration recurrence. Approximately 40% of patients with ulcerations will have a recurrent ulcer in the year after healing, and most occur in the first 3 months after wound healing. Hence, this period after ulceration is called "remission" due to this risk of reulceration. Promoting and fostering mobility is an integral part of everyday life and is important for maintaining good physical health and health-related quality of life for all people living with diabetes. In this short perspective, we provide recommendations on how to safely increase walking activity and facilitate appropriate off-loading and monitoring in people with a recently healed foot ulcer, foot reconstruction, or partial foot amputation. Interventions include monitored activity training, dosed out in steadily increasing increments and coupled with daily skin temperature monitoring, which can identify dangerous "hotspots" prone to recurrence. By understanding areas at risk, patients are empowered to maximize ulcer-free days and to enable an improved quality of life. This perspective outlines a unified strategy to treat patients in the remission period after ulceration and aims to provide clinicians with appropriate patient recommendations based on best available evidence and expert opinion to educate their patients to ensure a safe transition to footwear and return to activity.

Is There an Association between Sleep Disorders and Diabetic Foot? A Scoping Review

Diabetic foot is associated with a low quality of life since physical disabilities, mood disturbances and psychological disorders are frequent. One of the most important biological processes to ensure quality of life is sleep. Sleep disorders can impair glycemic control in patients with diabetes mellitus or even cause long-term type 2 diabetes mellitus. The aim of this study is to carry out a scoping review about the association between sleep cycle disorders and diabetic foot. PubMed, Scopus, CINAHL, PEDro, Cochrane Library, SCIELO and EMBASE databases were chosen for the search and the following terms were used: "diabetic foot","sleep*","rest-activity","mood" and"behavior". All the studies should include outcome variables about sleep and diabetic foot. Finally, 12 articles were selected, all of whichwere observational. The most frequent variables were those regarding diabetic foot ulcer aspects and diabetic neuropathy on one side, and obstructive sleep apnea, sleep duration and sleep quality on the other side. The results suggest that there is a possible association between obstructive sleep apnea and the presence or history of diabetic foot ulcers. No direct associations between sleep quality or sleep duration and diabetic foot or diabetic foot ulcer variables have been found.

Should weight-bearing activity be reduced during healing of plantar diabetic foot ulcers, even when using appropriate offloading devices?

Physical activity is an essential part of general health and diabetes management. However, recommending weight-bearing physical activity for people with plantar diabetic foot ulcers is controversial, even when gold standard offloading devices are used, as it is commonly thought to delay healing. We aimed to narratively review relevant studies investigating the relationship between plantar diabetic foot ulcer healing and weight-bearing activity, plantar pressure and device adherence. We defined relevant studies as those from two systematic reviews, along with those identified since using a similar updated Pubmed search strategy. We identified six studies. One study found that more daily steps were associated with worse ulcer healing, three found no significant association between steps and ulcer healing, and in two others the association was unclear. Thus, there is weak evidence for an inverse relationship between weight-bearing physical activity and plantar ulcer healing while utilizing offloading devices. We propose a Diabetic foot Offloading and Activity framework to guide future research to find the optimal balance between the positive and negative effects of weight-bearing activity in the context of foot ulcers. We hope such future studies will shed more conclusive light on the impact of weight-bearing activity on healing of plantar diabetic foot ulcers.

Foot disease and physical function in older adults: A systematic review and meta-analysis

OBJECTIVES

To systematically assess the literature examining the association between foot disease (foot ulceration, infection, critical ischaemia and/or Charcot neuroarthropathy) and physical function in older adults.

METHODS

Literature search of MEDLINE, Embase and CINAHL was performed. Studies were included if foot disease and physical function were assessed in participants of mean or median age ≥ 65 years.

RESULTS

Of 2,574 abstracts screened, 19 studies (13 longitudinal, 6 cross-sectional) reporting on 5634 participants, 43% female, were included. Diabetes-related foot disease and critical ischaemia were most studied (n = 5017, 40% female). In 8 studies with control groups, foot disease was associated with poorer physical function. Meta-analysis of 5 studies (n = 1503, 45% female) found an association between foot disease and poorer physical function (SMD (95% CI): 1.00 (0.40, 1.62), P < 0.001).

CONCLUSION

Foot disease is associated with poorer physical function in older adults. Future research should include broader study populations and intervention strategies.

The Role of Foot-Loading Factors and Their Associations with Ulcer Development and Ulcer Healing in People with Diabetes: A Systematic Review

We aimed to comprehensively and systematically review studies associating key foot-loading factors (i.e., plantar pressure, weight-bearing activity, adherence or a combination thereof) with ulcer development and ulcer healing in people with diabetes. A systematic literature search was performed in PubMed and EMBASE. We included studies if barefoot or in-shoe plantar pressure, weight-bearing activity or footwear or device adherence was measured and associated with either ulcer development or ulcer healing in people with diabetes. Out of 1954 records, 36 studies were included and qualitatively analyzed. We found low to moderate quality evidence that lower barefoot plantar pressure and higher footwear and device adherence associate with lower risk of ulcer development and shorter healing times. For the other foot-loading factors, we found low quality evidence with limited or contradictory results. For combined measures of foot-loading factors, we found low quality evidence suggesting that lower cumulative plantar tissue stress is associated with lower risk of ulcer development and higher ulcer healing incidence. We conclude that evidence for barefoot plantar pressure and adherence in association with ulcer outcome is present, but is limited for the other foot-loading factors. More comprehensive investigation in particularly the combination of foot-loading factors may improve the evidence and targeting preventative treatment.

Leveraging smart technologies to improve the management of diabetic foot ulcers and extend ulcer-free days in remission

The prevalent and long neglected diabetic foot ulcer (DFU) and its related complications rank among the most debilitating and costly sequelae of diabetes. Management of the DFU is multifaceted and requires constant monitoring from patients, caregivers, and healthcare providers. The alarmingly high rates of recurrence of ulcerations in the diabetic foot requires a change in our approach to care and to the vernacular in the medical literature. Our efforts should be directed not only on healing of open wounds, but also on maximizing ulcer-free days for the patient in diabetic foot remission. The increasing development and use of technology within every aspect of our lives represents an opportunity for creative solutions to prevent or better manage this devastating condition. In particular, recent advances in wearable and mobile health technologies appear to show promise in measuring and modulating dangerous foot pressure and inflammation to extend remission and improve the quality of life for these most complex patients. This review article discusses how harnessing wearables and digital technologies may improve the management and optimize prevention of DFUs by identifying high-risk patients for triage and timely intervention, personalizing prescription of offloading, and improving adherence to protective footwear. While still in their infancy, we envisage a future network of skin-worn, jewellery-worn, and implantable sensors that, if allowed to effectively communicate with one another and the patient, could dramatically impact measuring, personalizing, and managing how we and the patients we serve move through our collective world.

Effectiveness of offloading interventions to heal foot ulcers in persons with diabetes: a systematic review

BACKGROUND

Offloading interventions are commonly used in clinical practice to heal foot ulcers. The aim of this updated systematic review is to investigate the effectiveness of offloading interventions to heal diabetic foot ulcers.

METHODS

We updated our previous systematic review search of PubMed, EMBASE, and Cochrane databases to also include original studies published between July 29, 2014 and August 13, 2018 relating to four offloading intervention categories in populations with diabetic foot ulcers: (a) offloading devices, (b) footwear, (c) other offloading techniques, and (d) surgical offloading techniques. Outcomes included ulcer healing, plantar pressure, ambulatory activity, adherence, adverse events, patient-reported measures, and cost-effectiveness. Included controlled studies were assessed for methodological quality and had key data extracted into evidence and risk of bias tables. Included non-controlled studies were summarised on a narrative basis.

RESULTS

We identified 41 studies from our updated search for a total of 165 included studies. Six included studies were meta-analyses, 26 randomised controlled trials (RCTs), 13 other controlled studies, and 120 non-controlled studies. Five meta-analyses and 12 RCTs provided high-quality evidence for non-removable knee-high offloading devices being more effective than removable offloading devices and therapeutic footwear for healing plantar forefoot and midfoot ulcers. Total contact casts (TCCs) and non-removable knee-high walkers were shown to be equally effective. Moderate-quality evidence exists for removable knee-high and ankle-high offloading devices being equally effective in healing, but knee-high devices have a larger effect on reducing plantar pressure and ambulatory activity. Low-quality evidence exists for the use of felted foam and surgical offloading to promote healing of plantar forefoot and midfoot ulcers. Very limited evidence exists for the efficacy of any offloading intervention for healing plantar heel ulcers, non-plantar ulcers, and neuropathic ulcers with infection or ischemia.

CONCLUSION

Strong evidence supports the use of non-removable knee-high offloading devices (either TCC or non-removable walker) as the first-choice offloading intervention for healing plantar neuropathic forefoot and midfoot ulcers. Removable offloading devices, either knee-high or ankle-high, are preferred as second choice over other offloading interventions. The evidence bases to support any other offloading intervention is still weak and more high-quality controlled studies are needed in these areas.

A randomized controlled clinical trial of a hypothermically stored amniotic membrane for use in diabetic foot ulcers

Aim: Determine the effectiveness of hypothermically stored amniotic membrane (HSAM) versus standard of care (SOC) in diabetic foot ulcers (DFUs). Methods: A randomized controlled trial was conducted on 76 DFUs analyzed digitally. Results: Cox wound closure for HSAM (38 wounds) was significantly greater (p = 0.04) at weeks 12 (60 vs 38%), and 16 (63 vs 38%). The probability of wound closure increased by 75% (Hazard Ratio = 1.75; 95% CI: 1.16–2.70). HSAM showed >60% reductions in area (82 vs 58%; p = 0.02) and depth (65 vs 39%; p = 0.04) versus SOC. Conclusion: HSAM increased frequency and probability of wound closure in DFUs versus SOC.

Moderate-to-Vigorous-Intensity Physical Activity Observed in People With Diabetes-Related Foot Ulcers Over a One-Week Period

BACKGROUND

Regular moderate-to-vigorous-intensity physical activity results in health benefits in people with diabetes. No study has observed the moderate-to-vigorous-intensity physical activity typically performed by people with diabetes-related foot ulcers (DFU) in their everyday free-living environments. We observed the bouts, and accumulated time, spent doing moderate-to-vigorous-intensity physical activity in cases with DFU compared with diabetes-related peripheral neuropathy (DPN) and diabetes (DM) controls over a one-week period.

METHODS

This was a secondary analysis of a cross-sectional case-control study. Participants wore a multisensor device for >5 days (>22 hours per day). Primary outcomes included the number, duration (minutes) and intensity (metabolic equivalent tasks [METs]) of bouts of moderate-to-vigorous-intensity physical activity (defined as at least >3 METs for >10 consecutive minutes). Secondary outcomes included the total accumulated times spent doing moderate-to-vigorous-intensity physical activity (>3 METs) and doing sedentary-intensity activity (<1.5 METs). DFU subgroups with minor amputations and nonremovable offloading devices were also analyzed.

RESULTS

Overall, 15 DM, 23 DPN, and 27 DFU participants were included. All groups recorded similar low median daily numbers (0.33, 0.29, 0.25 numbers, respectively), duration (15, 17, 14 minutes), and intensity of daily bouts of moderate-to-vigorous-intensity physical activity (4.1, 4.3, 3.9 METs) (all, P > .1). Median accumulated daily time spent doing moderate-to-vigorous-intensity physical activity was also similar (40, 37, 36 minutes; P > .8). Those with DFU had more mean accumulated daily time spent doing sedentary-intensity activity (796 minutes) compared to DPN (720 minutes; P < .05), but not compared to DM (728 minutes; P < .08). DFU subgroups with minor amputations had more median accumulated daily time spent doing moderate-to-vigorous-intensity physical activity (66, 28 minutes; P < .05) and less mean time doing sedentary-intensity activity (745, 837; P < .05) than those without amputations.

CONCLUSIONS

People with DFU performed similar low numbers of daily bouts of moderate-to-vigorous-intensity physical activity to controls, but spend more time doing sedentary-intensity activities. Interventions that gradually increase the moderate-to-vigorous-intensity physical activity in people with DFU should be investigated.

Measuring Plantar Tissue Stress in People With Diabetic Peripheral Neuropathy: A Critical Concept in Diabetic Foot Management

Excessive stress on plantar tissue over time is one of the leading causes of diabetic foot ulcers among people with diabetic peripheral neuropathy. Plantar tissue stress (PTS) is a concept that attempts to integrate several well-known mechanical factors into one measure, including plantar pressure, shear stress, daily weight-bearing activity, and time spent in prescribed offloading interventions (adherence). Despite international diabetic foot guidelines recommending the measure of each of these individual mechanical factors in people with neuropathy, only recently has technology enabled their combined measurement to determine PTS. In this article we review the concept of PTS, the mechanical factors involved, and the findings of pivotal articles reporting measures of PTS in people with neuropathy. We also discuss key existing gaps in this field, including the lack of standards to measure and report PTS, a lack of practical solutions to measure shear stress, and the lack of PTS thresholds that may indicate benefit or detriment to people with neuropathy. To address some of these gaps, we propose recommended clinical and research standards for measuring and reporting PTS in people with neuropathy. Last, we forecast future clinical, research, and technological advancements that may use PTS to highlight the importance of this critical concept in the prevention and management of diabetic foot ulcers.

A nursing metaparadigm perspective of diabetic foot ulcer care

Diabetic foot ulcers (DFUs) are a serious complication of diabetes that impact on the patient, their social environment, overall health, and on nursing practice. Nursing scholars have integrated theories on practice to overcome these problems, but a lack of agreement in the available literature acts as a barrier to implementing these in practice. For that reason, using a nursing metaparadigm as a theoretical framework would assist nurses in managing care purposefully and proactively, thus possibly improving outcomes. There has been little discussion about the nursing metaparadigm in relation to DFU care. This article aims to identify why Fawcett's theory of the nursing metaparadigm is important as a fundamental part of DFU care. Understanding this will help to elucidate the phenomenon of DFUs. Moreover, identifying the elements of the DFU care framework is essential to improve reflective practice and intervention. This article discusses the concept of the nursing metaparadigm and its implications for practice in the care of patients with DFUs.

An exploratory study on differences in cumulative plantar tissue stress between healing and non-healing plantar neuropathic diabetic foot ulcers

BACKGROUND

Mechanical stress is important in causing and healing plantar diabetic foot ulcers, but almost always studied as peak pressure only. Measuring cumulative plantar tissue stress combines plantar pressure and ambulatory activity, and better defines the load on ulcers. Our aim was to explore differences in cumulative plantar tissue stress between people with healing and non-healing plantar diabetic foot ulcers.

METHODS

We analyzed a subgroup of 31 patients from a randomized clinical trial, treated with a removable offloading device for their plantar diabetic forefoot ulcer. We measured in-device dynamic plantar pressure and daily stride count to calculate cumulative plantar tissue stress at the ulcer location and associated this with ulcer healing and ulcer surface area reduction at four weeks (Student's t and chi-square test for significance, Cohen's d for effect size).

FINDINGS

In 12 weeks, 68% (n = 21) of the ulcers healed and 32% (n = 10) did not. No statistically significant differences were found for cumulative plantar tissue stress, plantar pressure or ambulatory activity between people with healed and not-healed ulcers. Cumulative plantar tissue stress was 25% lower for people with healed ulcers (155 vs. 207 MPa·s/day; P = 0.71; Effect size: d = 0.29). Post-hoc analyses in the 27 patients who self-reported to be adherent to wearing the device showed that cumulative plantar tissue stress was 49% lower for those who reached ≥75% ulcer surface area reduction at four weeks (140 vs. 275 MPa·s/day; P = 0.09; d = 0.76); smaller differences and effect sizes were found for peak pressure (24%), peak pressure-time integral (30%) and ambulatory activity (26%); (P-value range: 0.14-0.97; Cohen's d range: 0.14-0.70).

INTERPRETATION

Measuring cumulative plantar tissue stress may provide insight beyond that obtained from plantar pressure or ambulatory activity alone, with regard to diabetic foot ulcer healing using removable offloading devices. These explorative findings provide baseline data for further studies on this relevant topic.