The effect of removing plugs and adding arch support to foam based insoles on plantar pressures in people with diabetic peripheral neuropathy

The effect of calcaneus and metatarsal head offloading insoles on healthy subjects' gait kinematics, kinetics, asymmetry, and the implications for plantar pressure management: A pilot study

BACKGROUND

The global number of people with diabetes is estimated to reach 643 million by 2030 of whom 19-34% will present with diabetic foot ulceration. Insoles which offload high-risk ulcerative regions on the foot, by removing insole material, are the main contemporary conservative treatment to maintain mobility and reduce the likelihood of ulceration. However, their effect on the rest of the foot and relationship with key gait propulsive and balance kinematics and kinetics has not been well researched.

PURPOSE

The aim of this study is to investigate the effect of offloading insoles on gait kinematics, kinetics, and plantar pressure throughout the gait cycle.

METHODS

10 healthy subjects were recruited for this experiment to walk in 6 different insole conditions. Subjects walked at three speeds on a treadmill for 10 minutes while both plantar pressure and gait kinematics, kinetics were measured using an in-shoe pressure measurement insole and motion capture system/force plates. Average peak plantar pressure, pressure time integrals, gait kinematics and centre of force were analysed.

RESULTS

The average peak plantar pressure and pressure time integrals changed by -30% (-68% to 3%) and -36% (-75% to -1%) at the region of interest when applying offloading insoles, whereas the heel strike and toe-off velocity changed by 15% (-6% to 32%) and 12% (-2% to 19%) whilst walking at three speeds.

CONCLUSION

The study found that offloading insoles reduced plantar pressure in the region of interest with loading transferred to surrounding regions increasing the risk of higher pressure time integrals in these locations. Heel strike and toe-off velocities were increased under certain configurations of offloading insoles which may explain the higher plantar pressures and supporting the potential of integrating kinematic gait variables within a more optimal therapeutic approach. However, there was inter-individual variability in responses for all variables measured supporting individualised prescription.

Plantar pressure thresholds as a strategy to prevent diabetic foot ulcers: A systematic review

Background

The development of ulcers in the plantar region of the diabetic foot originates mainly from sites subjected to high pressure. The monitoring of these events using maximum allowable pressure thresholds is a fundamental procedure in the prevention of ulceration and its recurrence.

Objective

The aim of this review was to identify data in the literature that reveal an objective threshold of plantar pressure in the diabetic foot, where pressure is classified as promoting ulceration. The aim is not to determine the best and only pressure threshold for ulceration, but rather to clarify the threshold values most used in clinical practice and research, also considering the devices used and possible applications for offloading plantar pressure.

Design

A systematic review.

Methods

The search was performed in three electronic databases, by the PRISMA methodology, for studies that used a pressure threshold to minimize the risk of ulceration in the diabetic foot. The selected studies were subjected to eligibility criteria.

Results

Twenty-six studies were included in this review. Seven thresholds were identified, five of which are intended for the inside of the shoe: a threshold of average peak pressure of 200 kPa; 25 % and 40-80 % reduction from initial baseline pressure; 32-35 mm Hg for a capillary perfusion pressure; and a matrix of thresholds based on patient risk, shoe size and foot region. Two other thresholds are intended for the barefoot, 450 and 750 kPa. The threshold of 200 kPa of pressure inside the shoe is the most agreed upon among the studies. Regarding the prevention of ulceration and its recurrence, the efficacy of the proposed threshold matrix and the threshold of reducing baseline pressure by 40-80 % has not yet been evaluated, and the evidence for the remaining thresholds still needs further studies.

Conclusions

Some heterogeneity was found in the studies, especially regarding the measurement systems used, the number of regions of interest and the number of steps to be considered for the threshold. Even so, this review reveals the way forward to obtain a threshold indicative of an effective steppingstone in the prevention of diabetic foot ulcer.

The effects of different inner pressures of air insoles and walking durations on peak plantar pressure

BACKGROUND

Exercise reduces chronic complications in individuals with diabetes and peripheral vascular diseases. In clinical practice, the use of air insole may reduce peak plantar pressure (PPP), and risk for diabetic foot ulcers (DFUs). However, there is no guideline on selecting air insole pressure for effectively reducing PPP. Therefore, this study aimed to investigate the effects of different air insole pressure on PPP at different walking durations.

METHODS

We tested 13 participants using repeated measures study design, including 3 air insole pressures (80, 160, and 240 mm Hg) and 2 walking durations (10 and 20 minutes) for 6 walking conditions. PPP values at the first toe, first metatarsal head, and second metatarsal head were calculated.

RESULTS

The one-way ANOVA showed significant pairwise differences of PPP at 20 minutes duration in the first metatarsal head between 80 and 240 mm Hg (P = .007) and between 160 and 240 mm Hg (P = .038); in the second metatarsal head between 80 and 240 mm Hg (P = .043). The paired t test confirmed that walking duration significantly has lower PPP at 10 minutes than 20 minutes with 240 mm Hg air insole in the first metatarsal head (P = .012) and the second metatarsal head (P = .027).

CONCLUSION

People at risk of foot ulcers are suggested to wear shoes with 80 mm Hg of air insole for reducing PPP in the first metatarsal head and the second metatarsal head. Moreover, people may avoid wearing the stiffer insole (240 mm Hg) for more than 20 minutes.

Effective and clinically relevant optimisation of cushioning stiffness to maximise the offloading capacity of diabetic footwear

INTRODUCTION

Optimising the cushioning stiffness of diabetic footwear/orthoses can significantly enhance their offloading capacity. This study explores whether optimum cushioning stiffness can be predicted using simple demographic and anthropometric parameters.

METHODS

Sixty-nine adults with diabetes and loss of protective sensation in their feet were recruited for this cross-sectional observational study. In-shoe plantar pressure was measured using Pedar® for a neutral diabetic shoe (baseline) and after adding cushioning footbeds of varying stiffness. The cushioning stiffness that achieved maximum offloading was identified for each participant. The link between optimum cushioning stiffness and plantar loading or demographic/anthropometric parameters was assessed using multinomial regression.

RESULTS

People with higher baseline plantar loading required stiffer cushioning materials for maximum offloading. Using sex, age, weight, height, and shoe-size as covariates correctly predicted the cushioning stiffness that minimised peak pressure across the entire foot, or specifically in the metatarsal heads, midfoot and heel regions in 70%, 72%, 83% and 66% of participants respectively.

CONCLUSIONS

Increased plantar loading is associated with the need for stiffer cushioning materials for maximum offloading. Patient-specific optimum cushioning stiffness can be predicted using five simple demographic/anthropometric parameters. These results open the way for methods to optimise cushioning stiffness as part of clinical practice.

Effects of contoured insoles with different materials on plantar pressure offloading in diabetic elderly during gait

To investigate the effect of contoured insoles constructed of different insole materials, including Nora Lunalastik EVA, Nora Lunalight A fresh, Pe-Lite, and PORON Medical 4708 with Langer Biomechanics longitudinal PPT arch pads on offloading plantar pressure on the foot of the elderly with Type 1 or 2 diabetes during gait. Twenty-two elderly with Type 1 or 2 diabetes participated in the study. Their plantar pressure was measured by using an insole measurement system, while the participants walked 10 m in their bare feet or used each experimental insole in random order. The plantar surface was divided into four specific regions including the toes, forefoot, midfoot, and rearfoot. The mean peak pressure (MPP) and pressure-time integral (PTI) of ten steps with or without wearing one of the four insoles were analyzed on the dominant foot and the four specific plantar regions. After completion of the activities, the participants scored each insole from 1 (the least comfortable) to 10 (the most comfortable). The analysis of variance (ANOVA) factor of the insoles had significant effects on the MPP (P < 0.001) and PTI (P = 0.004) in the dominant foot during gait. Pairwise comparison results showed that the MPP and PTI in the dominant foot were significantly lower (P < 0.001) with PORON Medical 4708 than barefoot, Nora Lunalight A fresh, and Pe-Lite. Additionally, the insole materials had a significant effect for the forefoot (P < 0.001) and rearfoot (P < 0.001) in terms of the MPP and PTI compared with the barefoot condition during gait. Regardless of the plantar region, the MPP and PTI values were the lowest when PORON Medical 4708 was used as the insole material among four insole materials. Meanwhile, a significantly lower MPP and PTI can be found in the forefoot and rearfoot with the use of the four experimental insoles when compared with barefoot. The soft insole materials (i.e., PORON medical 4708 and Nora Lunalastik EVA) had a better performance than the rigid insole materials (i.e., Nora Lunalight A fresh, and Pe-Lite) on plantar pressure offloading for diabetic elderly.

Design optimization procedure for an orthopedic insole having a continuously variable stiffness/shape to reduce the plantar pressure in the foot of a diabetic patient

Foot ulcers and lower-limb amputations are among the major problems in diabetic patients. Orthopedic insoles can reduce the risk of diabetic foot ulcers in patients through pressure redistribution on the bottom of the foot. The purpose of this study was to propose an optimization method to design the dedicated insoles for diabetic patients in order to decrease the maximum plantar pressure. At first, a three-dimensional finite element model of bones, ligaments and soft tissue of a diabetic patient's foot was created using CT scan images. Then, the foot plantar pressure was calculated by means of a finite element software. Next, the stiffness and shape of a simple flat insole were separately modified to reduce the maximum foot plantar pressure. The optimization method resulted in a dedicated insole design with a continuously variable stiffness/shape within its area that creates a smooth pressure distribution for the patient comfort. The results showed a 40% reduction in the maximum foot pressure, which we attribute to the modification of insole stiffness. In addition, the optimal shape of the proposed insole decreased the maximum plantar pressure by 25% compared to the flat insole.

Knee-High Devices Are Gold in Closing the Foot Ulcer Gap: A Review of Offloading Treatments to Heal Diabetic Foot Ulcers

Diabetic foot ulcers (DFU) are a leading cause of the global disease burden. Most DFUs are caused, and prolonged, by high plantar tissue stress under the insensate foot of a person with peripheral neuropathy. Multiple different offloading treatments have been used to try to reduce high plantar tissue stress and heal DFUs, including bedrest, casting, offloading devices, footwear, and surgical procedures. The best offloading treatments are those that balance the benefits of maximizing reductions in high plantar tissue stress, whilst reducing the risks of poor satisfaction, high costs and potential adverse events outcomes. This review aimed to summarize the best available evidence on the effects of offloading treatments to heal people with DFUs, plus review their use in clinical practice, the common barriers and solutions to using these treatments, and discuss promising emerging solutions that may improve offloading treatments in future. Findings demonstrate that knee-high offloading devices, non-removable or removable knee-high devices worn for all weight-bearing activities, are the gold standard offloading treatments to heal most patients with DFU, as they are much more effective, and typically safer, quicker, and cheaper to use compared with other offloading treatments. The effectiveness of offloading treatments also seems to increase when increased offloading mechanical features are incorporated within treatments, including customized insoles, rocker-bottom soles, controlled ankle motion, and higher cast walls. However, in clinical practice these gold standard knee-high offloading devices have low rates of prescription by clinicians and low rates of acceptance or adherence by patients. The common barriers resulting in this low use seem to surround historical misperceptions that are mostly dispelled by contemporary evidence. Further, research is now urgently required to close the implementation gap between the high-quality of supporting evidence and the low use of knee-high devices in clinical practice to reduce the high global disease burden of DFU in future.

In-shoe pressure thresholds for people with diabetes and neuropathy at risk of ulceration: A systematic review

INTRODUCTION

In-shoe pressure thresholds play an increasingly important role in the prevention of diabetes-related foot ulceration (DFU). The evidence of their effectiveness, methodological consistency and scope for refinement are the subject of this review.

METHODS

1107 records were identified (after duplicate removal) based on a search of five databases for studies which applied a specific in-shoe pressure threshold to reduce the risk of ulceration. 37 full text studies were assessed for eligibility of which 21 were included.

RESULTS

Five in-shoe pressure thresholds were identified, which are employed to reduce the risk of diabetes-related foot ulceration: a mean peak pressure threshold of 200 kPa used in conjunction with a 25% baseline reduction target; a sustained pressure threshold of 35 mm Hg, a threshold matrix based on risk, shoe size and foot region, and a 40-80% baseline pressure reduction target. The effectiveness of the latter two thresholds have not been assessed yet and the evidence for the effectiveness of the other in-shoe pressure thresholds is limited, based only on two RCTs and two cohort studies.

CONCLUSIONS

The heterogeneity of current measures precludes meta-analysis and further research and methodological standardisation is required to facilitate ready comparison and the further development of these pressure thresholds.

Footwear and insole design features for offloading the diabetic at risk foot-A systematic review and meta-analyses

The aim of this systematic review was to identify the best footwear and insole design features for offloading the plantar surface of the foot to prevent foot ulceration in people with diabetic peripheral neuropathy. We searched multiple databases for published and unpublished studies reporting offloading footwear and insoles for people with diabetic neuropathy and nonulcerated feet. Primary outcome was foot ulcer incidence; other outcome measures considered were any standardized kinetic or kinematic measure indicating loading or offloading the plantar foot. Fifty-four studies, including randomized controlled studies, cohort studies, case-series, and a case-controlled and cross-sectional study were included. Three meta-analyses were conducted and random-effects modelling found peak plantar pressure reduction of arch profile (37 kPa (MD, -37.5; 95% CI, -72.29 to -3.61; P < .03), metatarsal addition (35.96 kPa (MD, -35.96; 95% CI, -57.33 to -14.60; P < .001) and pressure informed design 75.4 kPa (MD, -75.4 kPa; 95% CI, -127.4 to -23.44 kPa; P < .004).The remaining data were presented in a narrative form due to heterogeneity. This review highlights the difficulty in differentiating the effect of different insole and footwear features in offloading the neuropathic diabetic foot. However, arch profiles, metatarsal additions and apertures are effective in reducing plantar pressure. The use of pressure analysis to enhance the effectiveness of the design of footwear and insoles, particularly through modification, is recommended.

Footwear and insole design features that reduce neuropathic plantar forefoot ulcer risk in people with diabetes: a systematic literature review

BACKGROUND

In people with diabetes, offloading high-risk foot regions by optimising footwear, or insoles, may prevent ulceration. This systematic review aimed to summarise and evaluate the evidence for footwear and insole features that reduce pathological plantar pressures and the occurrence of diabetic neuropathy ulceration at the plantar forefoot in people with diabetic neuropathy.

METHODS

Six electronic databases (Medline, Cinahl, Amed, Proquest, Scopus, Academic Search Premier) were searched in July 2019. The search period was from 1987 to July 2019. Articles, in English, using footwear or insoles as interventions in patients with diabetic neuropathy were reviewed. Any study design was eligible for inclusion except systematic literature reviews and case reports. Search terms were diabetic foot, physiopathology, foot deformities, neuropath*, footwear, orthoses, shoe, footwear prescription, insole, sock*, ulcer prevention, offloading, foot ulcer, plantar pressure.

RESULTS

Twenty-five studies were reviewed. The included articles used repeated measure (n = 12), case-control (n = 3), prospective cohort (n = 2), randomised crossover (n = 1), and randomised controlled trial (RCT) (n = 7) designs. This involved a total of 2063 participants. Eleven studies investigated footwear, and 14 studies investigated insoles as an intervention. Six studies investigated ulcer recurrence; no study investigated the first occurrence of ulceration. The most commonly examined outcome measures were peak plantar pressure, pressure-time integral and total contact area. Methodological quality varied. Strong evidence existed for rocker soles to reduce peak plantar pressure. Moderate evidence existed for custom insoles to offload forefoot plantar pressure. There was weak evidence that insole contact area influenced plantar pressure.

CONCLUSION

Rocker soles, custom-made insoles with metatarsal additions and a high degree of contact between the insole and foot reduce plantar pressures in a manner that may reduce ulcer occurrence. Most studies rely on reduction in plantar pressure measures as an outcome, rather than the occurrence of ulceration. There is limited evidence to inform footwear and insole interventions and prescription in this population. Further high-quality studies in this field are required.

Optimised cushioning in diabetic footwear can significantly enhance their capacity to reduce plantar pressure

BACKGROUND

Plantar pressure reduction with the use of cushioning materials play an important role in the clinical management of the diabetic foot. Previous studies in people without diabetes have shown that appropriate selection of the stiffness of such materials can significantly enhance their capacity to reduce pressure. However the significance of optimised cushioning has not been yet assessed for people with diabetic foot syndrome.

RESEARCH QUESTION

What is the potential benefit of using footwear with optimised cushioning, with regards to plantar pressure reduction, in people with diabetes and peripheral neuropathy?

METHODS

Plantar pressure distribution was measured during walking for fifteen people with diabetic foot syndrome in a cohort observational study. The participants were asked to walk in the same type of footwear that was fitted with 3D-printed footbeds. These footbeds were used to change the stiffness of the entire sole-complex of the shoe; from very soft to very stiff. The stiffness that achieved the highest pressure reduction relative to a no-footbed condition was identified as the patient-specific optimum one.

RESULTS

The use of the patient-specific optimum stiffness reduced, on average, peak pressure by 46% (±14%). Using the same stiffness across all participants lowered the footwears' capacity for pressure reduction by at least nine percentile points (37% ± 17%); a statistically significant difference (paired samples t-test, t(13) = -3.733, p = 0.003, d = 0.997). Pearson correlation analysis indicated that patient-specific optimum stiffness was significantly correlated with the participants' body mass index (BMI), with stiffer materials needed for people with higher BMI (rs(14) = 0.609, p = 0.021).

SIGNIFICANCE

This study offers the first quantitative evidence in support of optimising cushioning in diabetic footwear as part of standard clinical practice. Further research is needed to develop a clinically applicable method to help professionals working with diabetic feet identify the optimum cushioning stiffness on a patient-specific basis.

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.

State of the art design protocol for custom made footwear for people with diabetes and peripheral neuropathy

Supported by evidence-based guidelines, custom-made footwear is often prescribed to people with diabetes who are at risk for ulceration. However, these guidelines do not specify the footwear design features, despite available scientific evidence for these features. We aimed to develop a design protocol to support custom-made footwear prescription for people with diabetes and peripheral neuropathy. The population of interest was people with diabetes who are at moderate-to-high risk of developing a foot ulcer, for whom custom-made footwear (shoes and/or insoles) can be prescribed. A group of experts from rehabilitation medicine, orthopaedic shoe technology (pedorthics) and diabetic foot research, reviewed the scientific literature and met during 12 face-to-face meetings to develop a footwear design algorithm and evidence-based pressure-relief algorithm as parts of the protocol. Consensus was reached where evidence was not available. Fourteen domains of foot pathology in combination with loss of protective sensation were specified for the footwear design algorithm and for each domain shoe-specific and insole (orthosis)-specific features were defined. Most insole-related features and some shoe-related features were evidence based, whereas most shoe-related features were consensus based. The pressure-relief algorithm was evidence based using recent footwear trial data and specifically targeted patients with a healed plantar foot ulcer. These footwear design and pressure-relief algorithms are the first of their kind and should facilitate more uniform decision making in the prescription and manufacturing of adequate shoes for moderate-to-high-risk patients, reducing variation in footwear provision and improving clinical outcome in the prevention of diabetic foot ulcers.

Treatment of modifiable risk factors for foot ulceration in persons with diabetes: a systematic review

BACKGROUND

Prevention of diabetic foot ulcers is important. Preventative treatment mostly targets and aims to improve modifiable risk factors of foot ulceration. While effectiveness of interventions in ulcer prevention has been systematically reviewed, their effectiveness in improving modifiable risk factors is unknown.

METHODS

The available medical scientific literature in PubMed, Excerpta Medica Database, and the Cochrane database was searched for original research studies on six interventions to treat modifiable risk factors for diabetic foot ulceration (ie, education for patients; education for professionals; self-management; pre-ulcer treatment; orthotic interventions; and foot- and mobility-related exercises). We assessed interventions for eight outcomes (ie, patients' knowledge; treatment adherence; professionals' knowledge; pre-ulcers; mechanical stress; neuropathy symptoms; foot/ankle joint mobility; and foot function). Both controlled and noncontrolled studies were selected. Data from controlled studies were assessed for methodological quality by two independent reviewers and extracted and presented in evidence and risk of bias tables.

RESULTS

We included 72 publications (26 with a controlled study design and 46 noncontrolled). We found that structured education may improve foot self-care behaviour of patients, yearly foot examinations, and foot disease knowledge of health care professionals. Callus removal reduces peak plantar pressure. Custom-made therapeutic footwear can be effective in reducing plantar pressure and may reduce callus. Foot- and mobility-related exercises may improve neuropathy symptoms and foot and ankle joint range of motion, while they do not seem to reduce peak plantar pressure; evidence for their effect on foot strength is conflicting.

CONCLUSIONS

Structured education for patients and health care professionals, callus removal, custom-made therapeutic footwear, and foot- and mobility-related exercises may be beneficial for improving modifiable risk factors for foot ulceration. However, we generally found low quality of evidence for interventions targeting modifiable risk factors for ulceration in persons with diabetes, with frequently inconsistent or limited results available per intervention and outcome.

INSoles To Ease Pressure (INSTEP) Study: a multicentre, randomised controlled feasibility study to compare the effectiveness of a novel instant optimised insole with a standard insole for people with diabetic neuropathy: a study protocol

INTRODUCTION

Foot ulceration is a multifactorial complication of diabetes. Therapeutic insoles and footwear are frequently used to reduce elevated tissue pressures associated with risk of foot ulceration. A novel protocol using in-shoe pressure measurement technology to provide an instant optimised insole and house shoe solution has been developed, with the aim of reducing foot ulceration.

AIM

This study aims to assess the feasibility of conducting a multicentre randomised controlled trial to compare the effectiveness of a novel instant optimised insole with a standard insole for people with diabetic neuropathy.

METHODS AND ANALYSIS

This study is a participant and assessor blinded, randomised, multicentre parallel group feasibility trial with embedded qualitative study. Seventy-six participants will be recruited from three podiatry clinics and randomised to an optimised insole plus usual care (intervention group) or standard insole plus usual care (control group) using a minimisation by randomisation procedure by study centre and previous ulcer status. Assessment visits and data collection will be at baseline, 3 months, 6 months and 12 months. Feasibility and acceptability of the trial procedures will be determined in terms of recruitment and retention rates, data completion rates, intervention adherence and effectiveness of the blinding.Assessment of the appropriateness and performance of outcome measures will inform selection of the primary and secondary outcomes and sample size estimate for the anticipated definitive randomised controlled trial. Clinical outcomes include incidence of plantar foot ulceration and change in peak plantar pressure. Twelve participants (four from each centre) and three treating podiatrists (one from each centre) will be interviewed to explore their experiences of receiving and delivering the intervention.

ETHICS AND DISSEMINATION

The study was approved by the South-West Exeter Research Ethics Committee. Findings will be disseminated through conference presentations, public platforms and academic publications.

TRIALS REGISTRATION NUMBER

ISRCTN16011830; Pre-results.

Footwear and offloading interventions to prevent and heal foot ulcers and reduce plantar pressure in patients with diabetes: a systematic review

BACKGROUND

Footwear and offloading techniques are commonly used in clinical practice for preventing and healing of foot ulcers in persons with diabetes. The goal of this systematic review is to assess the medical scientific literature on this topic to better inform clinical practice about effective treatment.

METHODS

We searched the medical scientific literature indexed in PubMed, EMBASE, CINAHL, and the Cochrane database for original research studies published since 1 May 2006 related to four groups of interventions: (1) casting; (2) footwear; (3) surgical offloading; and (4) other offloading interventions. Primary outcomes were ulcer prevention, ulcer healing, and pressure reduction. We reviewed both controlled and non-controlled studies. Controlled studies were assessed for methodological quality, and extracted key data was presented in evidence and risk of bias tables. Uncontrolled studies were assessed and summarized on a narrative basis. Outcomes are presented and discussed in conjunction with data from our previous systematic review covering the literature from before 1 May 2006.

RESULTS

We included two systematic reviews and meta-analyses, 32 randomized controlled trials, 15 other controlled studies, and another 127 non-controlled studies. Several randomized controlled trials with low risk of bias show the efficacy of therapeutic footwear that demonstrates to relief plantar pressure and is worn by the patient, in the prevention of plantar foot ulcer recurrence. Two meta-analyses show non-removable offloading to be more effective than removable offloading for healing plantar neuropathic forefoot ulcers. Due to the limited number of controlled studies, clear evidence on the efficacy of surgical offloading and felted foam is not yet available. Interestingly, surgical offloading seems more effective in preventing than in healing ulcers. A number of controlled and uncontrolled studies show that plantar pressure can be reduced by several conservative and surgical approaches.

CONCLUSIONS

Sufficient evidence of good quality supports the use of non-removable offloading to heal plantar neuropathic forefoot ulcers and therapeutic footwear with demonstrated pressure relief that is worn by the patient to prevent plantar foot ulcer recurrence. The evidence base to support the use of other offloading interventions is still limited and of variable quality. The evidence for the use of interventions to prevent a first foot ulcer or heal ischemic, infected, non-plantar, or proximal foot ulcers is practically non-existent. High-quality controlled studies are needed in these areas.

Data-driven directions for effective footwear provision for the high-risk diabetic foot

AIMS

Custom-made footwear is used to offload the diabetic foot to prevent plantar foot ulcers. This prospective study evaluates the offloading effects of modifying custom-made footwear and aims to provide data-driven directions for the provision of effectively offloading footwear in clinical practice.

METHODS

Eighty-five people with diabetic neuropathy and a recently healed plantar foot ulcer, who participated in a clinical trial on footwear effectiveness, had their custom-made footwear evaluated with in-shoe plantar pressure measurements at three-monthly intervals. Footwear was modified when peak pressure was ≥ 200 kPa. The effect of single and combined footwear modifications on in-shoe peak pressure at these high-pressure target locations was assessed.

RESULTS

All footwear modifications significantly reduced peak pressure at the target locations compared with pre-modification levels (range -6.7% to -24.0%, P < 0.001). The metatarsal heads were most frequently targeted. Repositioning an existing (trans-)metatarsal pad in the shoe insole (-15.9% peak pressure relief), applying local cushioning to the insole (-15.0%) and replacing the insole top cover with Plastazote (-14.2%) were the most effective single modifications. Combining a new Plastazote top cover with a trans-metatarsal bar (-24.0% peak pressure relief) or with local cushioning (-22.0%) were the most effective combined modifications.

CONCLUSIONS

In people with diabetic neuropathy and a recently healed plantar foot ulcer, significant offloading can be achieved at high-risk foot regions by modifying custom-made footwear. These results provide data-driven directions for the design and evaluation of custom-made footwear for high-risk people with diabetes, and essentially mean that each shoe prescribed should incorporate those design features that effectively offload the foot.

Pilot study demonstrating that sole mechanosensitivity can be affected by insole use

Insoles are known to alter plantar loads and thus plantar sensory input. We therefore hypothesised that plantar somatosensory sensation could be modified over time by use of hard metatarsal pads. A sample of 12 healthy female participants was randomly allocated to either soft metatarsal pads (n=6, latex foam, Shore A11) or hard metatarsal pads groups (n = 6, thermoplastic, ShoreA65). All wore the same shoe type and pedometers measured daily activities. Using a bespoke actuated device, multiple mechanical stimuli were applied to the forefoot and rearfoot before and after 8 and 30 days of wearing the pads. A control test comprised estimation of multiple auditory sensations at day 0, 8 and 30. Changes in detection of the mechanical and sound stimuli were estimated using the Stevens power function, Ψ = k × Φ(n) (estimate = Ψ; stimulus = Φ). The k coefficient measured the sensitivity, i.e. the lowest detectable load/sound, and the n coefficient the gain in perception over time. After 30 days, hard metatarsal pads group had increased plantar sensitivity in the forefoot but not the rearfoot. The soft metatarsal pads group showed no changes in plantar sensitivity and the detection of auditory sensation remained stable over the 30 days.Metatarsal pads with relatively high hardness increased the perception of the lowest mechanical stimulus in the forefoot compared to soft metatarsal pads. This provides initial evidence of the potential for changes in plantar somatosensory sensation due to choice of orthotic designs in patients with foot-related problems.