Plantar pressure relief in the diabetic foot using forefoot offloading shoes

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.

Prevention of foot ulcers in persons with diabetes at risk of ulceration: A systematic review and meta-analysis

AIMS

Prevention of foot ulcers in persons with diabetes is important to help reduce the substantial burden on both individual and health resources. A comprehensive analysis of reported interventions is needed to better inform healthcare professionals about effective prevention. The aim of this systematic review and meta-analysis is to assess the effectiveness of interventions to prevent foot ulcers in persons with diabetes who are at risk thereof.

MATERIALS AND METHODS

We searched the available scientific literature in PubMed, EMBASE, CINAHL, Cochrane databases and trial registries for original research studies on preventative interventions. Both controlled and non-controlled studies were eligible for selection. Two independent reviewers assessed risk of bias of controlled studies and extracted data. A meta-analysis (using Mantel-Haenszel's statistical method and random effect models) was done when >1 RCT was available that met our criteria. Evidence statements, including the certainty of evidence, were formulated according to GRADE.

RESULTS

From the 19,349 records screened, 40 controlled studies (of which 33 were Randomised Controlled Trials [RCTs]) and 103 non-controlled studies were included. We found moderate certainty evidence that temperature monitoring (5 RCTs; risk ratio [RR]: 0.51; 95% CI: 0.31-0.84) and pressure-optimised therapeutic footwear or insoles (2 RCTs; RR: 0.62; 95% CI: 0.26-1.47) likely reduce the risk of plantar foot ulcer recurrence in people with diabetes at high risk. Further, we found low certainty evidence that structured education (5 RCTs; RR: 0.66; 95% CI: 0.37-1.19), therapeutic footwear (3 RCTs; RR: 0.53; 95% CI: 0.24-1.17), flexor tenotomy (1 RCT, 7 non-controlled studies, no meta-analysis), and integrated care (3 RCTs; RR: 0.78; 95% CI: 0.58-1.06) may reduce the risk of foot ulceration in people with diabetes at risk for foot ulceration.

CONCLUSIONS

Various interventions for persons with diabetes at risk for foot ulceration with evidence of effectiveness are available, including temperature monitoring (pressure-optimised) therapeutic footwear, structured education, flexor tenotomy, and integrated foot care. With hardly any new intervention studies published in recent years, more effort to produce high-quality RCTs is urgently needed to further improve the evidence base. This is especially relevant for educational and psychological interventions, for integrated care approaches for persons at high risk of ulceration, and for interventions specifically targeting persons at low-to-moderate risk of ulceration.

An exploratory study of dynamic foot shape measurements with 4D scanning system

Accurate and reliable foot measurements at different stances offer comprehensive geometrical information on foot, thus enabling a more comfortable insole/footwear for practical use and daily activities. However, there lacks investigations on continuous deformation of foot shape during the roll-over process. This study analyses the foot deformation of 19 female diabetic patients during half weight bearing standing and self-selected walking speed by using a novel 4D foot scanning system. The scanning system has good repeatability and accuracy in both static and dynamic scanning situations. Point cloud registration for scanned image reorientation and algorithms to automatically extract foot measurements is developed. During the foot roll-over process, maximum deformation of length and girth dimensions are found at first toe contact. Width dimensions have maximum deformation at heel take off. The findings provide a new understanding of foot shape changes in dynamic situations, thus providing an optimal solution for foot comfort, function and protection.

Analysis of Diabetic Foot Deformation and Plantar Pressure Distribution of Women at Different Walking Speeds

Official guidelines state that suitable physical activity is recommended for patients with diabetes mellitus. However, since walking at a rapid pace could be associated with increased plantar pressure and potential foot pain, the footwear condition is particularly important for optimal foot protection in order to reduce the risk of tissue injury and ulceration of diabetic patients. This study aims to analyze foot deformation and plantar pressure distribution at three different walking speeds (slow, normal, and fast walking) in dynamic situations. The dynamic foot shape of 19 female diabetic patients at three walking speeds is obtained by using a novel 4D foot scanning system. Their plantar pressure distributions at the three walking speeds are also measured by using the Pedar in-shoe system. The pressure changes in the toes, metatarsal heads, medial and lateral midfoot, and heel areas are systematically investigated. Although a faster walking speed shows slightly larger foot measurements than the two other walking speeds, the difference is insignificant. The foot measurement changes at the forefoot and heel areas, such as the toe angles and heel width, are found to increase more readily than the measurements at the midfoot. The mean peak plantar pressure shows a significant increase at a faster walking speed with the exception of the midfoot, especially at the forefoot and heel areas. However, the pressure time integral decreases for all of the foot regions with an increase in walking speed. Suitable offloading devices are essential for diabetic patients, particularly during brisk walking. Design features such as medial arch support, wide toe box, and suitable insole material for specific area of the foot (such as polyurethane for forefoot area and ethylene-vinyl acetate for heel area) are essential for diabetic insole/footwear to provide optimal fit and offloading. The findings contribute to enhancing the understanding of foot shape deformation and plantar pressure changes during dynamic situations, thus facilitating the design of footwear/insoles with optimal fit, wear comfort, and foot protection for diabetic patients.

Diabetic foot ulcers: Classification, risk factors and management

Diabetic foot ulceration is a devastating complication of diabetes that is associated with infection, amputation, and death, and is affecting increasing numbers of patients with diabetes mellitus. The pathogenesis of foot ulcers is complex, and different factors play major roles in different stages. The refractory nature of foot ulcer is reflected in that even after healing there is still a high recurrence rate and amputation rate, which means that management and nursing plans need to be considered carefully. The importance of establishment of measures for prevention and management of DFU has been emphasized. Therefore, a validated and appropriate DFU classification matching the progression is necessary for clinical diagnosis and management. In the first part of this review, we list several commonly used classification systems and describe their application conditions, scope, strengths, and limitations; in the second part, we briefly introduce the common risk factors for DFU, such as neuropathy, peripheral artery disease, foot deformities, diabetes complications, and obesity. Focusing on the relationship between the risk factors and DFU progression may facilitate prevention and timely management; in the last part, we emphasize the importance of preventive education, characterize several of the most frequently used management approaches, including glycemic control, exercise, offloading, and infection control, and call for taking into account and weighing the quality of life during the formulation of treatment plans. Multidisciplinary intervention and management of diabetic foot ulcers (DFUs) based on the effective and systematic combination of these three components will contribute to the prevention and treatment of DFUs, and improve their prognosis.

A novel workflow to fabricate a patient-specific 3D printed accommodative foot orthosis with personalized latticed metamaterial

Patients with diabetes mellitus are at elevated risk for secondary complications that result in lower extremity amputations. Standard of care to prevent these complications involves prescribing custom accommodative insoles that use inefficient and outdated fabrication processes including milling and hand carving. A new thrust of custom 3D printed insoles has shown promise in producing corrective insoles but has not explored accommodative diabetic insoles. Our novel contribution is a metamaterial design application that allows the insole stiffness to vary regionally following patient-specific plantar pressure measurements. We presented a novel workflow to fabricate custom 3D printed elastomeric insoles, a testing method to evaluate the durability, shear stiffness, and compressive stiffness of insole material samples, and a case study to demonstrate how the novel 3D printed insoles performed clinically. Our 3D printed insoles results showed a matched or improved durability, a reduced shear stiffness, and a reduction in plantar pressure in clinical case study compared to standard of care insoles.

Foot deformation analysis with different load-bearing conditions to enhance diabetic footwear designs

In-depth analyses of foot surface measurements upon weight bearing are crucial to understand how the dorsal and plantar surfaces of the foot deform during motion to enhance the fit of footwear, which is particularly important for diabetic patients with stringent fit requirements to redistribute the plantar weight forces. This study analyzes diabetic foot deformations under 3 different weight bearing conditions (no weight bearing, half weight bearing, and 80% weight bearing) by using a novel foot scanning method that enables efficient scanning of the dorsal and plantar surfaces of the foot simultaneously. The feet of 48 patients with diabetes mellitus (DM) are scanned. With increased load on the feet, the width of the forefoot increases by 9.7%-10.4%, height of the midfoot decreases by 15.1%-18.2%, forefoot and midfoot rotate to the medial side by 16.9%-23.9% while the rearfoot rotates to the lateral side by 15.2% simultaneously, and the plantar of the foot increases contact with the floor by 11.4%-23.0%. Gender differences in foot shape are also found between males and females, males have a broader foot than females for the same foot length. Precise anthropometric information of foot changes and deformation therefore enables adequate foot protection, fit and comfort when designing footwear. This research contributes to shoe design considerations that focus on the deformation of the foot under different loads.

Recovery of the Foot Loading Patterns of Children with Excess Weight after Losing Weight: A 3-Year Longitudinal Study

It is suggested that children with excess weight should lose weight to reduce plantar pressure and the risk of related injuries. However, whether the foot loading patterns of these children could return to normal after weight loss is unclear. A total of 147 children participated in this longitudinal study; 51 were selected for analysis—13 children who were overweight and 1 child with obesity reduced their weight to normal levels and 37 children maintained normal weights (control group). The plantar pressure parameters, including peak pressure, maximum force, and force-time integral were recorded using a Footscan plate system. Comparisons of plantar parameters and load transferences revealed that weight loss could effectively decrease the differences in foot loading distributions between the weight-reduced and normal-weight groups. After losing weight, the foot loading patterns of the children who were overweight recovered to the level of normal-weight children, and that of the child with obesity failed to reach the normal level. Losing weight is suggested for children who are overweight/obese to recover their foot loading patterns, to avoid further adverse influences on the foot/functioning caused by excessive weight-bearing. Further research exploring the findings of a cohort of children with obesity—who reduce their weight to normal levels—is warranted.

Footwear comfort: a systematic search and narrative synthesis of the literature

OBJECTIVE

To provide a narrative synthesis of the research literature pertaining to footwear comfort, including definitions, measurement scales, footwear design features, and physiological and psychological factors.

METHODS

A systematic search was conducted which yielded 101 manuscripts. The most relevant manuscripts were selected based on the predetermined subheadings of the review (definitions, measurement scales, footwear design features, and physiological and psychological factors). A narrative synthesis of the findings of the included studies was undertaken.

RESULTS

The available evidence is highly fragmented and incorporates a wide range of study designs, participants, and assessment approaches, making it challenging to draw strong conclusions or implications for clinical practice. However, it can be broadly concluded that (i) simple visual analog scales may provide a reliable overall assessment of comfort, (ii) well-fitted, lightweight shoes with soft midsoles and curved rocker-soles are generally perceived to be most comfortable, and (iii) the influence of sole flexibility, shoe microclimate and insoles is less clear and likely to be more specific to the population, setting and task being performed.

CONCLUSION

Footwear comfort is a complex and multifaceted concept that is influenced not only by structural and functional aspects of shoe design, but also task requirements and anatomical and physiological differences between individuals. Further research is required to delineate the contribution of specific shoe features more clearly, and to better understand the interaction between footwear features and individual physiological attributes.

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.

Load Transference with the Gain of Excessive Body Mass: A Two-Year Longitudinal Study

Previous studies investigating the effect of excessive weight on the foot have commonly been cross-sectional; therefore, it is still unclear how the foot function gradually changes with the increased body mass that is physiologically gained over time. This study aimed to use a load transfer method to identify the mechanism of how the foot function changed with the increased excessive body mass over two years. Taking normal weight as the baseline, fifteen children became overweight or obese (group 1), and fifteen counterparts maintained normal weight (group 0) over the two years. Barefoot walking was assessed using a Footscan^® plate system. A load transfer method was used based upon the relative force–time integral (FTI) to provide an insight into plantar load transference as children increased in weight. Significantly increased FTIs were found at the big toe (BT), medial metatarsal (MM), lateral metatarsal (LM), and lateral heel (HL) in group 1, while at BT, MM, medial heel (HM), and HL in group 0. Foot load showed a posterior to anterior transferal from midfoot (2.5%) and heel (7.0%) to metatarsal and big toe in group 1. The control group, however, shifted the loading within the metatarsal level from LM to HM (4.1%), and equally relieved weight from around the midfoot (MF) (3.0%) to BT, MM, HM and HL. Earlier weight loss intervention is required to prevent further adverse effects on foot functions caused by excessive weight-bearing.

Effects of novel diabetic therapeutic footwear on preventing ulcer recurrence in patients with a history of diabetic foot ulceration: study protocol for an open-label, randomized, controlled trial

BACKGROUND

Recurrence after the healing of a foot ulcer is very common among patients with diabetes mellitus. Novel diabetic therapeutic footwear consisted of merino wool, vibration chip, and orthopedic insoles is designed to influence multifaceted mechanisms of foot ulcer occurrence. The aim of this study is to examine the effect of the optimally designed therapeutic footwear on preventing ulcer recurrence in patients with a history of diabetic foot ulcers (DFU).

METHODS/DESIGN

The trial is designed as a two arms, parallel-group, open-label randomized controlled intervention study. The Log-rank Test was used for calculating sample size based on the latest national multicenter survey data of DFU in China. Three hundred and twenty participants will be recruited from the Diabetic Foot Care Center, West China Hospital, Sichuan University. Adults with diabetic peripheral neuropathy, healed foot ulceration in the 3 months prior to randomization, and aged ≥18 years, will be recruited. Participants will be randomized to receive novel diabetic therapeutic footwear (n = 160) or their own footwear (n = 160). The primary outcome will be the incidence of ulcer recurrence. The secondary outcome will be measurements of barefoot dynamic plantar pressures, the influence of footwear adherence on ulcer recurrence, and the incidence of cardiovascular events. Assessment visits and data collection will be obtained at baseline, 1, 3, 6, 9, and 12 months. The intention-to-treat principle will be applied. A cox regression model will be used to calculate the hazard ratio for the incidence of ulcer recurrence. The change of barefoot dynamic plantar pressures will be assessed using repeated measures ANOVA. The study protocol has been approved by the Ethics Committee of The Biomedical Research Ethics Committee of West China Hospital, Sichuan University (Reference No. 2019(96)).

DISCUSSION

This clinical trial will give information on the ability of novel diabetic footwear on preventing ulcer recurrence in patients with a history of diabetic foot ulceration. If the optimally designed therapeutic footwear does work well, the findings will contribute to the development of innovative treatment devices for preventing foot ulcer recurrence in high-risk patients.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR1900025538 . Registered on 31 August 2019.

Variations in plantar pressure variables across elliptical trainers in older adults

BACKGROUND

Ellipticals are used to address walking and cardiorespiratory training goals of older adults, some of whom are at risk for foot injuries. Variations in joint kinematics and muscle demands when using different ellipticals could lead to plantar pressure differences. This study explored plantar pressure variables during gait and use of four ellipticals.

METHODS

Plantar pressures were recorded while 10 adults [68.1 (4.5) years] walked and used the True, Octane, Life Fitness, and SportsArt ellipticals. Repeated-measures ANOVAs (5 × 1) identified forefoot and heel differences across conditions.

FINDINGS

Maximum forefoot forces and peak pressures were significantly lower than walking for each elliptical condition with one exception (Life Fitness peak pressure). However, sustained elliptical pedal contact time contributed to forefoot pressure-time integrals and dosages (i.e., cumulative pressure during one minute of activity) not varying significantly amongst elliptical and walking conditions. Heel maximum forces and peak pressures were significantly lower than walking during all elliptical conditions except SportsArt. Heel contact time on SportsArt and Octane exceeded walking, and SportsArt heel contact time exceeded Life Fitness. Heel pressure-time integral was greater on SportsArt compared to walking, Life Fitness, and True. Sports Art heel dosage exceeded Life Fitness and True.

INTERPRETATION

While elliptical training's sustained double limb support diminished maximal forces and peak pressures under the forefoot and heel compared to walking, each ellipticals' pressure-time integral and dosage were not significantly lower than walking. These findings point to the importance of carefully initiating elliptical training programs to minimize tissue injury, particularly if sensory neuropathy is present.

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.

Differences in loading patterns between fast walking and jogging at the same speed in male adults

Abstract

Fast walking and jogging are two common exercises for people to maintain health in daily life. But the differences in loading patterns of fast walking and jogging are still unclear. The purpose of this study was to compare loading patterns in fast walking and jogging at the same speed, and to identify how differences in foot mechanics influence plantar pressure distribution between the two modes of gait. Totally, 49 healthy males participated in this study. Data of pressure parameters, including maximum force (MF), peak pressure (PP), contact area (CA), force-time integral (FTI), were recorded by Pedar-X insole plantar pressure measurement system in participants’ fast walking and jogging process at 7 km/h. A Load transfer analysis method was used to quantify the plantar load transference from fast walking to jogging. The results showed that MF, PP and CA increased in metatarsal regions and midfoot regions while decreased in toes regions and heel during jogging when compared with fast walking. FTI decreased in all foot regions during jogging compared to fast walking. Under the effects of spring mechanics and the varus of rearfoot during jogging, fast walking and jogging reveal different loading patterns. Compared jogging to fast walking, load transferred as follow: 1) in transverse direction, load transferred from lateral foot to medial foot in metatarsal regions and midfoot regions, 2) in longitudinal direction, load transferred from toes to the metatarsal, and from heel to the metatarsal and midfoot. These results also provide suggestions for footwear designs.

Graphical abstract

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.

Guidelines on offloading foot ulcers in persons with diabetes (IWGDF 2019 update)

The International Working Group on the Diabetic Foot (IWGDF) has published evidence-based guidelines on the prevention and management of diabetic foot disease since 1999. This guideline is on the use of offloading interventions to promote the healing of foot ulcers in people with diabetes and updates the previous IWGDF guideline. We followed the GRADE methodology to devise clinical questions and critically important outcomes in the PICO format, to conduct a systematic review of the medical-scientific literature, and to write recommendations and their rationale. The recommendations are based on the quality of evidence found in the systematic review, expert opinion where evidence was not available, and a weighing of the benefits and harms, patient preferences, feasibility and applicability, and costs related to the intervention. For healing a neuropathic plantar forefoot or midfoot ulcer in a person with diabetes, we recommend that a nonremovable knee-high offloading device is the first choice of offloading treatment. A removable knee-high and removable ankle-high offloading device are to be considered as the second- and third-choice offloading treatment, respectively, if contraindications or patient intolerance to nonremovable offloading exist. Appropriately, fitting footwear combined with felted foam can be considered as the fourth-choice offloading treatment. If non-surgical offloading fails, we recommend to consider surgical offloading interventions for healing metatarsal head and digital ulcers. We have added new recommendations for the use of offloading treatment for healing ulcers that are complicated with infection or ischaemia and for healing plantar heel ulcers. Offloading is arguably the most important of multiple interventions needed to heal a neuropathic plantar foot ulcer in a person with diabetes. Following these recommendations will help health care professionals and teams provide better care for diabetic patients who have a foot ulcer and are at risk for infection, hospitalization, and amputation.

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.

Stepease™ diabetic socks: An answer to efficacious indoor foot pressure relief- A prospective study

BACKGROUND

Diabetic foot ulcer is commonly seen in people with diabetes mellitus. Inadequate plantar pressure offloading has been identified as a contributing factor to development of diabetic foot ulcers. Various pressure off-loading footwear are widely available in the market but poor compliance has been reported especially for indoor usage. StepEase™ diabetic socks have been designed using Ethylene Vinyl Acetate (EVA) microspheres for better redistribution of plantar pressure. The objective of this study was to determine the efficacy of StepEase™ in redistributing the foot plantar pressure and to assess patients' satisfaction on the usage of the socks.

METHODS

This was a prospective non randomized clinical trial conducted on 31 patients with diabetes mellitus with high risk foot (King's classification stage II) over a 12 weeks period. Dynamic foot plantar pressure reading was recorded at day 0, 6 weeks and 12 weeks intervals, both barefoot and with StepEase™, using Novel Pedar-X system (Novel GmbH, Munich, Germany). Patients' satisfaction and usage practice were assessed by a questionnaire.

RESULTS

The mean age of subjects was 57.9 years with mean body mass index (BMI) of 26 kg/m². The mean duration of diagnosis with diabetes mellitus was 10.2 years. The mean peak plantar pressure was found to be highest at the right forefoot and left heel region, 267.6 kPa (SD113.5 kPa) and 266.3 kPa (SD 94.6 kPa) respectively. There was a statistically significant reduction of mean peak pressure (P < 0.0001 to P = 0.024) in all masked regions except the left toe region ranging from 22.3 to 47.5% (53.2-117.4 kPa). The highest reduction was seen in the right toe region (47.5%). The reduction of peak pressure was still significant (P < 0.0001 to P = 0.034) at 6 weeks ranging from 24.7% to 46.8% (46.1-100.6 kPa) and at 12 weeks, which was 22.2-49.2% (40.6-91.9 kPa). Mean usage of the socks was 4.39 days per week (SD 1.82), with the mode of 4-6 h per day. Most of the subjects were satisfied or very satisfied with the StepEase™ socks (77.4%) while 87.1% agreed to continue using the socks. None had any new ulcer development or fall during the study period.

CONCLUSION

StepEase™ was significantly effective as an indoor foot pressure relieving footwear. It resulted in significant peak plantar pressure reduction by up to 49.2% and the effect was maintained for at least 12 weeks duration.

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.

Plantar pressure changes in hindfoot relief devices of different designs

BACKGROUND

It is frequently observed that overloading the foot can impair bone and soft tissue healing and can lead to harmful sequelae (i.e. ulcers, stress reactions) in context of pre-existing tissue disabilities. In terms of offloading, hindfoot relief devices are commonly applied as a non-operative treatment as well as after various surgical procedures for hindfoot disorders. Despite their common use, there is a paucity of data comparing different orthotic devices with respect to changes in plantar pressure distributions. The aim of this study was to investigate plantar loadings in hindfoot relief devices of different designs.

METHODS

Twenty-five healthy participants (13 women, 12 men; (mean ± SD) age 37 ± 14 years; BMI 23 ± 4 kg/m2) were recruited. Plantar pressure distributions were collected using i.) a neutral shoe, ii.) a hindfoot relief shoe (HRS) and iii.) a hindfoot relief orthosis (HRO). Peak pressure values were measured via dynamic pedobarography during walking and were analysed from four different plantar regions: the hindfoot, midfoot, metatarsal I-V and forefoot. As a reference standard, the normal walk using neutral shoes served as the condition for full weight-bearing.

RESULTS

Concerning the hindfoot, using the HRS as well as the HRO resulted in significant decreases in plantar pressures compared to baseline values that were obtained with the neutral shoe (- 52% for the HRS and - 52% for the HRO, p < 0.001). Significant increases in peak pressures were found in the midfoot region for both devices (HRS: 32%, p = 0.002; HRO: 47%, p < 0.001). For the metatarsal region, peak pressures were found to decrease significantly (HRS: - 52%, p < 0.001; HRO: -17%, p = 0.034). With respect to the forefoot, a significant reduction in peak pressures using the HRS (- 41%, p < 0.001) was detected, whereas the HRO did not lead to significant changes (- 4%, p = 0.691).

CONCLUSIONS

Both the HRO and HRS significantly reduced plantar hindfoot pressure, corresponding to a relative decrease of nearly 50% of the baseline. Nevertheless, the adjacent midfoot zone displayed a significant increase in plantar pressure values for both devices. Supported by these findings, physicians should cautiously consider a substantial increase in midfoot loading, especially in patients affected by additional midfoot injuries or accompanying impairments of tissue healing.

LEVEL OF EVIDENCE

IV, Case series.

The Evaluation of Foot Rockers on the Kinematic Parameters of Individuals With Diabetes

BACKGROUND

A variety of shoe modifications have been used to reduce the forces applied on the plantar surface of the foot in those with diabetes. Toe and heel rockers are 2 of the most common types used. The aim of this study is to evaluate the effect of these shoe modifications on the kinematics of both normal and diabetic individuals.

METHOD

Two groups of healthy and diabetic individuals were recruited for this study. The Qualysis motion analysis system was used to record the motions of participants while walking with shoes with toe and a combination of toe and heel rockers (combined). The effects of the type of rockers used and the effect of groups were determined using MANOVA.

RESULTS

Results of the study demonstrated no discernible difference between the spatiotemporal and range of motion of the ankle, knee, and hip joints while walking with a toe and combined rockers. There was also no difference between healthy and diabetic individuals in relation to these parameters (P value >.05).

CONCLUSION

Results of this study demonstrated no difference between the spatiotemporal and range of motion of lower-limb joints in healthy and diabetic individuals when walking with toe and combined rockers. Because the use of these rockers did not influence the kinematics of the joints while walking, it is recommended that they be used for this group of individuals if they influence the forces applied on the foot.

LEVELS OF EVIDENCE

Level IV.

Effect of different casting design characteristics on offloading the diabetic foot

BACKGROUND

Non-removable knee-high devices, such as a total contact cast (TCC), are recommended for offloading diabetic plantar forefoot ulcers. However, it is insufficiently known how each of the different design characteristics of these devices contribute to offloading the diabetic foot.

RESEARCH QUESTION

What is the offloading effect of the different design characteristics that make up a non-removable knee-high cast for people with diabetes and active or previous plantar forefoot ulcers?

METHODS

Sixteen persons with diabetes, peripheral neuropathy and a healed or active plantar forefoot ulcer had their plantar pressures measured during walking in a non-removable knee-high device (TCC), in that device made removable (BTCC), in that device made below-ankle (cast shoe), in that cast shoe worn with a different walking sole and in a newly made cast shoe without a custom-moulded foot-device interface. Peak pressures, force-time integral, and perceived walking comfort were assessed.

RESULTS

Compared with the BTCC, peak pressures in the TCC were 47% (P = 0.028), 26% (P = 0.003) and 15% (P = 0.050) lower at the hallux, midfoot and (previous) ulcer location, respectively. Compared to the cast shoe, peak pressures in the BTCC were 39-43% and 47% (both P < 0.001) lower in the forefoot regions and (previous) ulcer location, respectively. The total force-time integral was 21% and 11% (P < 0.007) lower in the TCC and BTCC compared to the cast shoe. Perceived walking comfort was 5.6 in the TCC and 6.5 in the BTCC (P = 0.037). Effects of the other design characteristics (i.e. walking sole and plantar moulding) were non-significant.

SIGNIFICANCE

The TCC gives superior offloading, mostly because of being a knee-high and non-removable device, providing an optimal 'shaft effect'. The TCC does, however, negatively affect walking comfort. These results aid decision-making in offloading diabetic plantar forefoot ulcers.

Shoe-Insole Technology for Injury Prevention in Walking

Impaired walking increases injury risk during locomotion, including falls-related acute injuries and overuse damage to lower limb joints. Gait impairments seriously restrict voluntary, habitual engagement in injury prevention activities, such as recreational walking and exercise. There is, therefore, an urgent need for technology-based interventions for gait disorders that are cost effective, willingly taken-up, and provide immediate positive effects on walking. Gait control using shoe-insoles has potential as an effective population-based intervention, and new sensor technologies will enhance the effectiveness of these devices. Shoe-insole modifications include: (i) ankle joint support for falls prevention; (ii) shock absorption by utilising lower-resilience materials at the heel; (iii) improving reaction speed by stimulating cutaneous receptors; and (iv) preserving dynamic balance via foot centre of pressure control. Using sensor technology, such as in-shoe pressure measurement and motion capture systems, gait can be precisely monitored, allowing us to visualise how shoe-insoles change walking patterns. In addition, in-shoe systems, such as pressure monitoring and inertial sensors, can be incorporated into the insole to monitor gait in real-time. Inertial sensors coupled with in-shoe foot pressure sensors and global positioning systems (GPS) could be used to monitor spatiotemporal parameters in real-time. Real-time, online data management will enable &lsquo;big-data&rsquo; applications to everyday gait control characteristics.

Lower-extremity dynamics of walking in neuropathic diabetic patients who wear a forefoot-offloading shoe

BACKGROUND

A forefoot-offloading shoes has a negative-heel rocker outsole and is used to treat diabetic plantar forefoot ulcers, but its mechanisms of action and their association with offloading and gait stability are not sufficiently clear.

METHODS

Ten neuropathic diabetic patients were tested in a forefoot-offloading shoe and subsequently in a control shoe with no specific offloading construction, both worn on the right foot (control shoe on left), while walking at 1.2m/s. 3D-instrumented gait analysis and simultaneous in-shoe plantar pressure measurements were used to explain the shoe's offloading efficacy and to define centre-of-pressure profiles and left-to-right symmetry in ankle joint dynamics (0-1, 1:maximum symmetry), as indicators for gait stability.

FINDINGS

Compared to the control shoe, peak forefoot pressures, vertical ground reaction force, plantar flexion angle, and ankle joint moment, all in terminal stance, and the proximal-to-distal centre-of-pressure trajectory were significantly reduced in the forefoot-offloading shoe (P<0.01). Peak ankle joint power was 51% lower in the forefoot-offloading shoe compared to the control shoe: 1.61 (0.35) versus 3.30 (0.84) W/kg (mean (SD), P<0.001), and was significantly associated with forefoot peak pressure (R²=0.72, P<0.001). Left-to-right symmetry in the forefoot-offloading shoe was 0.39 for peak ankle joint power.

INTERPRETATION

By virtue to their negative-heel rocker-outsole design, forefoot-offloading shoes significantly alter a neuropathic diabetic patient's gait towards a reduced push-off power that explains the shoe's offloading efficacy. However, gait symmetry and stability are compromised, and may be factors in the low perceived walking discomfort and limited use of these shoes in clinical practice. Shoe modifications (e.g. less negative heel, a more cushioning insole) may resolve this trade-off between efficacy and usability.

Effects of flexible and rigid rocker profiles on in-shoe pressure

Rocker profiles are commonly used in the prevention of diabetic foot ulcers. Rockers are mostly stiffened to restrict toe plantarflexion to ensure proper offloading. It is also described that toe dorsiflexion should be restricted. However, the difference in effect on plantar pressure between rigid rockers that restrict this motion and flexible rockers that do not is unknown. In-shoe plantar pressure data were collected for a control shoe and the same shoe with rigid and flexible rockers with the apex positioned at 50% and 60%. For 29 healthy female adults peak plantar pressure (PP), maximum mean pressure (MMP) and force-time integral (FTI) were determined for seven regions of the foot. Generalized estimate equation was used to analyse the effect of the different shoes on the outcome measures for these regions. Compared to the control shoe a significant increase of PP and FTI was found at the first toe for both rigid rockers and the flexible rocker with the apex positioned at 60%, while MMP was significantly increased in rockers with an apex position of 60% (p<0.001). PP at the first toe was significantly lower in flexible rockers when compared to rigid rockers (p<0.001). For both central and lateral forefoot PP and MMP were significantly more reduced in rigid rockers (p<0.001), while for the medial forefoot no differences were found. The use of rigid rockers results in larger reductions of forefoot plantar pressures, but in worse increase of plantar pressures at the first toe compared to rockers that allow toe dorsiflexion.

The Role of Pressure Offloading on Diabetic Foot Ulcer Healing and Prevention of Recurrence

BACKGROUND

An increased plantar pressure is a causative factor in the development of plantar foot ulcers in people with diabetes mellitus, and ulcers are a precursor of lower extremity amputation.

METHODS

In this article, the evidence is reviewed that relieving areas of increased plantar pressure (ie, offloading) can heal plantar foot ulcers and prevent their recurrence.

RESULTS

Noninfected, nonischemic neuropathic plantar forefoot ulcers should heal in 6 to 8 weeks with adequate offloading. Recent meta-analyses and systematic reviews show that nonremovable knee-high devices are most effective. This is probably because they eliminate the problem of nonadherence with the use of a removable device. Studies show a large discrepancy between evidence-based recommendations on offloading and what is used in clinical practice. Many clinics continue to use methods that are less effective or have not been proven to be effective, while ignoring evidence-based methods. Strategies are proposed to address this issue, notably the adoption and implementation of recent international guidelines by professional societies and a stronger focus of clinicians on expedited healing. For the prevention of plantar foot ulcer recurrence in high-risk patients, 2 recent trials have shown that the incidence of recurrence can be significantly reduced with custom-made footwear that has a demonstrated pressure-relieving effect through guidance by plantar pressure measurements, under the condition that the footwear is worn.

CONCLUSION

This review helps to inform clinicians about effective offloading treatment for healing plantar foot ulcers and preventing their recurrence.

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.

Pedobarographic and kinematic analysis in the functional evaluation of two post-operative forefoot offloading shoes

BACKGROUND

Forefoot offloading shoes are special orthopaedic footwear designed to protect and unload the injured part of the foot after surgery and for conservative treatments. The offloading action is often achieved by transferring plantar load to the rearfoot via rocker shoes with reduced contact area between shoe and ground. While these shoes are intended to be worn only for short periods, a compromise must be found between functionality and the risk of alterations in gait patterns at the lower limb joints. In this study, the pedobarographic, kinematic and kinetic effects of a traditional half-shoe and a double-rocker full-outsole shoe were compared to those of a comfortable shoe (control).

METHODS

Ten healthy female participants (28.2 ± 10.0 years) were asked to walk in three different footwear conditions for the left/right foot: control/half-shoe, control/full-outsole, and control/control. Full gait analysis was obtained in three walking trials for each participant in each condition. Simultaneously a sensor insole system recorded plantar pressure in different foot regions. Normalized root-mean-square error, coefficient of determination, and frame-by-frame statistical analysis were used to assess differences in time-histories of kinematic and kinetic parameters between shoes.

RESULTS

The half -shoe group showed the slowest walking speed and the shortest stride length. Forefoot plantar load was significantly reduced in the half-shoe (maximum force as % of Body Weight: half-shoe = 62.1; full-outsole = 86.9; control = 93.5; p < 0.001). At the rearfoot, mean pressure was the highest in the full-outsole shoe. At the ankle, sagittal-plane kinematics in the full-outsole shoe had a pattern more similar to control.

CONCLUSIONS

The half-shoe appears significantly more effective in reducing plantar load at the forefoot than a double-rocker full-outsole shoe, which is designed to reduce forefoot loading by using an insole with a thicker profile anteriorly as to maintain the foot in slight dorsiflexion. However, the half-shoe is also associated with altered gait spatio-temporal parameters, more kinematic modifications at the proximal lower limb joints and reduced propulsion in late stance.

Plantar loading reflects ulceration risks of diabetic foot with toe deformation

Diabetes has been one of the most common chronic diseases all over the world. The purpose of this study was to quantitatively assess the foot loading characteristics of diabetic patients with fifth-toe deformity through a comparative analysis with diabetic patients with healthy and normal feet. Six neuropathic diabetic female subjects with the fifth-toe deformation and six age-matched neuropathic diabetic controls without any feet deformities participated in the walking test. Dynamic barefoot plantar pressure was measured with Novel EMED force plate. Peak pressure and pressure-time integral for all 7 foot regions (rearfoot, midfoot, lateral forefoot, central forefoot, medial forefoot, great toe, and other toes) were collected. Peak pressure was significantly higher in the patients with toe deformity in rearfoot, central forefoot, and great toe regions compared with the control group. Meanwhile, loading sustaining period extended longer in great toe region of deformed group than in that of the control group, and the center of pressure was nearly in the big toe region during toe offstage. Diabetic patients with fifth-toe deformity could have plantar contact area reduction in the other toes part and increased loading to the great toe part. The result showed that fifth-toe deformity was associated with potential ulceration risk especially in hallux region.

Orthotic management of the neuropathic foot: an interdisciplinary care perspective

BACKGROUND

Clinical management of the patient with neuropathic foot is becoming commonplace in orthotic clinics worldwide. The presentations that can result from neuropathic foot are diverse, requiring clinicians to understand the pathomechanics of ulceration, infection, and Charcot joint arthropathy to provide effective interventions.

OBJECTIVES

The purpose of this clinical perspective is to provide a review of the literature regarding clinical concepts associated with orthotic management of neuropathic foot.

STUDY DESIGN

Literature review and clinical case study.

METHODS

Relevant literature were reviewed and summarized, and a clinical case study synthesizing reviewed concepts was presented.

RESULTS

Given the multifactorial nature of the neuropathic foot, treatments must be multifaceted and patient-specific to effectively address the underlying disease processes. While systemic issues such as peripheral arterial disease are treated by physicians, local issues such as foot deformity are managed by orthotists. Orthotic interventions commonly include custom footwear to reduce the risk of ulceration through creation of a protective environment or targeted plantar offloading. Patient and caregiver education to encourage management compliance is equally as important to ensure successful treatment.

CONCLUSION

Patients with neuropathic foot benefit from an interdisciplinary care approach which engages physicians, wound care practitioners, and orthotists to treat and manage systemic and local problems. Addressing this pathology through interdisciplinary care may positively affect the patient's health status while lowering associated healthcare costs through improved treatment efficacy.

CLINICAL RELEVANCE

The commonality of neuropathic foot and associated complications including ulceration, infection, and Charcot joint arthropathy requires that the patient care team have a fundamental understanding of these pathologies and common treatment modalities. We review orthotic treatment modalities to assist clinicians with the management of patients with neuropathic foot.

The effect of good and poor walking shoe characteristics on plantar pressure and gait in people with gout

BACKGROUND

Previous research has shown that good footwear characteristics may reduce foot pain and foot-related disability in people with gout. The aim of this study was to determine the effect of good and poor footwear characteristics on plantar pressure and spatiotemporal parameters of gait in people with gout.

METHODS

Thirty-six people with gout participated in a cross-sectional repeated measures study. Plantar pressure and spatiotemporal parameters were recorded in two shoe conditions: (1) the participants own footwear, and (2) either a new pair of walking shoes with good footwear characteristics (n=21) or poor characteristics (n=15). Differences between good and poor shoe groups compared to participants own shoes were also determined.

FINDINGS

Compared to participant's own shoes, footwear with good characteristics significantly reduced peak pressure at metatarsal 3 and 5, reduced pressure time integrals beneath the heel and metatarsals 3 and 5 and increased pressure time integrals beneath the midfoot. The footwear with poor characteristics significantly increased peak pressure beneath the heel and lesser toes, reduced peak pressure at metatarsal 3 and reduced pressure time integrals in the midfoot compared to participants own shoes. Both good and poor footwear significantly increased walking velocity, step length, and stride length compared to participants own shoes.

INTERPRETATION

Walking shoes with good footwear characteristics can influence plantar pressure values and encourage a more efficient heel to toe gait pattern in people with gout. These changes may contribute to the reduction in foot pain and foot-related problems in this population.

[Vacuum shoe system vs.forefoot offloading shoe for the management of metatarsal fractures. A prospective, randomized trial]

BACKGROUND

Metatarsal fractures are managed using different types of forefoot offloading orthosis. Theaim of this prospective study was to evaluate the clinical and pedographic results of a vacuum shoe system in comparison to a forefoot unloading shoe.

METHOD

20 patients (14 women/6 men--age: 36.4 +/- 14.1 years) were prospectively included in the study. The patients were followed up at four different time points. Detailed clinical and radiological examinations were carried out, functional scores were measured and a pedographic assessment was performed.

RESULTS

Between the study groups no differences were seen in functional scoring. A complete bony healing was achieved within the 3 months of followup in all patients. The heelstrike to heelstrike time was without significant differences in the pedographic analysis. Adequate forefoot unloading was achieved with both orthosis. The load sharing between fore-, mid- and hindfoot showed no significant differences in the pedographic analysis. Patients' satisfaction was rated with higher values for the vacuum shoe system, but without significance.

CONCLUSION

Both shoe systems show an adequate unloading of the forefoot. Therefore both orthosis may be used for the treatment of metatarsal fractures.

Screening method based on walking plantar impulse for detecting musculoskeletal senescence and injury

No consensus has been reached on how musculoskeletal system injuries or aging can be explained by a walking plantar impulse. We standardize the plantar impulse by defining a principal axis of plantar impulse. Based upon this standardized plantar impulse, two indexes are presented: plantar pressure record time series and plantar-impulse distribution along the principal axis of plantar impulse. These indexes are applied to analyze the plantar impulse collected by plantar pressure plates from three sources: Achilles tendon ruptures; elderly people (ages 62-71); and young people (ages 19-23). Our findings reveal that plantar impulse distribution curves for Achilles tendon ruptures change irregularly with subjects' walking speed changes. When comparing distribution curves of the young, we see a significant difference in the elderly subjects' phalanges plantar pressure record time series. This verifies our hypothesis that a plantar impulse can function as a means to assess and evaluate musculoskeletal system injuries and aging.

Effect of a forefoot off-loading postoperative shoe on muscle activity, posture, and static balance

BACKGROUND

We investigated whether a forefoot off-loading postoperative shoe (FOPS) alters standing posture, ankle muscle activity, and static postural sway and whether any effects are altered by wearing a shoe raise on the contralateral side.

METHODS

Posture, ankle muscle activity, and postural sway were compared in 14 healthy participants wearing either a FOPS or a control shoe with or without a contralateral shoe raise. Participants were tested under different sensory and support surface conditions. Additionally, reductions in peak pressure under the forefoot while walking were assessed with and without a contralateral shoe raise to determine whether the FOPS continued to achieve its primary off-loading function.

RESULTS

Compared with the control condition, wearing a FOPS moved the center of pressure posteriorly, increased tibialis anterior muscle activity, and reduced ankle plantarflexor activity. These changes decreased when a contralateral shoe raise was added. No difference in postural sway was found between footwear conditions. Forefoot peak pressure was always reduced when wearing the FOPS.

CONCLUSIONS

The posterior shift in center of pressure toward and behind the ankle joint axis is believed to result in the increase in tibialis anterior muscle activity that now acts as the primary stabilizer around the ankle. Instability may, therefore, increase in patients with weak tibialis anterior muscles (eg, diabetic neuropathy) who need to wear offloading devices for ulcer management. We suggest that the addition of a contralateral shoe raise fitted with a FOPS may potentially be beneficial in maintaining stability while off-loading the forefoot in this patient group.

Effect of rocker shoe design features on forefoot plantar pressures in people with and without diabetes

BACKGROUND

There is no consensus on the precise rocker shoe outsole design that will optimally reduce plantar pressure in people with diabetes. This study aimed to understand how peak plantar pressure is influenced by systematically varying three design features which characterise a curved rocker shoe: apex angle, apex position and rocker angle.

METHODS

A total of 12 different rocker shoe designs, spanning a range of each of the three design features, were tested in 24 people with diabetes and 24 healthy participants. Each subject also wore a flexible control shoe. Peak plantar pressure, in four anatomical regions, was recorded for each of the 13 shoes during walking at a controlled speed.

FINDINGS

There were a number of significant main effects for each of the three design features, however, the precise effect of each feature varied between the different regions. The results demonstrated maximum pressure reduction in the 2nd-4th metatarsal regions (39%) but that lower rocker angles (<20°) and anterior apex positions (>60% shoe length) should be avoided for this region. The effect of apex angle was most pronounced in the 1st metatarsophalangeal region with a clear decrease in pressure as the apex angle was increased to 100°.

INTERPRETATION

We suggest that an outsole design with a 95° apex angle, apex position at 60% of shoe length and 20° rocker angle may achieve an optimal balance for offloading different regions of the forefoot. However, future studies incorporating additional design feature combinations, on high risk patients, are required to make definitive recommendations.

Comparison of the clinical effectiveness of different off-loading devices for the treatment of neuropathic foot ulcers in patients with diabetes: a systematic review and meta-analysis

Effective off-loading is considered to be an important part of the successful clinical management of diabetic foot ulcers. The aim of this systematic review is to investigate the safety and effectiveness of different off-loading devices for the treatment of diabetic foot ulcers. The medical literature was extensively searched from January 1966 to May 2012. Systematic reviews and controlled studies that compared the use of different off-loading devices formed the evidence base. Studies were critically appraised to determine their risk of methodological bias, and data were extracted. Results were pooled using random effects meta-analysis and tested for heterogeneity. When compared with removable devices, non-removable off-loading devices were found, on average, to be more effective at promoting the healing of diabetic foot ulcers (RRp  = 1.43; 95% CI 1.11, 1.84; I(2)  = 66.9%; p = 0.001; k = 10). Analysis, stratified by type of removable device, did not detect a statistically significant difference between non-removable off-loading devices and removable cast walkers; however, on average non-removable off-loading devices performed better than therapeutic shoes at promoting the healing of diabetic foot ulcers (RRp  = 1.68; 95% CI 1.09, 2.58; I(2)  = 71.5%; p = 0.004; k = 6). The two types of non-removable off-loading devices i.e. total contact casts and instant total contact casts (removable cast walker rendered irremovable by securing with bandage or lace), were found to be equally effective (RRp  = 1.06; 95% CI 0.88, 1.27; I(2)  = 3.3%; p = 0.31; k = 2). In conclusion, non-removable off-loading devices regardless of type, are more likely to result in ulcer healing than removable off-loading devices, presumably because patient compliance with off-loading is facilitated.

The value of reporting pressure-time integral data in addition to peak pressure data in studies on the diabetic foot: a systematic review

BACKGROUND

In plantar pressure studies on the diabetic foot, pressure-time integral data is often analyzed and reported next to peak pressure data, mostly because of its assumed additional value. The aim was to assess this additional value by systematically reviewing the relevant literature.

METHODS

The MEDLINE database was searched for original articles that report both pressure-time integral and peak pressure data measured in the diabetic foot. Eligible articles were assessed according to differences in reported results between both parameters, the quality of discussion and specific conclusions drawn on pressure-time integral data, and the added value of the pressure-time integral data.

FINDINGS

All 35 eligible papers described studies on gait. Differences in reported results between parameters were found to be clear, minimal, or absent in 15, 8, and 12 papers, respectively. In 15 papers, the pressure-time integral results were discussed with respect to the peak pressure results, but in only 5 papers the explanation given for reported differences was considered meaningful. Specific conclusions were drawn in 11 papers. Some added value was found in 10 papers, but in all papers one or more limitations to this value applied.

INTERPRETATION

The study findings suggest that the added value of reporting pressure-time integral data is limited. Unless clear benefit can be shown such, as that ulceration can be better predicted using pressure-time integral than using peak pressure data, the reporting of pressure-time integral data seems redundant to express the plantar loading in the diabetic foot.

Test-retest reliability of the Win-Track platform in analyzing the gait parameters and plantar pressures during barefoot walking in healthy adults

The Win-Track platform is an instrument used to measure plantar pressures and gait parameters during barefoot walking. The objective of this study was to determine the test-retest reliability of the system in assessing plantar pressures and temporal gait variables between 1-step and 3-step gait protocols. A total of 30 healthy participants (18 women and 12 men; age 23.7 ± 4.75 years) were recruited for the study. The 1-step gait protocol exhibited good reliability in terms of single stance, step duration and swing duration of the left foot; stride duration of the right foot; stride length; and step length of the right foot, with intraclass correlation coefficients (ICCs) ranging from 0.75 to 0.88. The 3-step gait protocol showed good reliability, with ICC values ranging between 0.75 and 0.90 in cadence; step duration of the right foot; double-stance duration and swing duration of the right foot; stride length of the right foot; step length and gait cycle length of the right and the left foot; and the area covered by the first, second, and third foot. The authors concluded that the Win-Track platform provided reliable plantar pressures and temporal gait measures, and the 3-step gait protocol showed better reliability compared with the 1-step gait protocol.

Classification of the severity of diabetic neuropathy: a new approach taking uncertainties into account using fuzzy logic

OBJECTIVE

This study proposes a new approach that considers uncertainty in predicting and quantifying the presence and severity of diabetic peripheral neuropathy.

METHODS

A rule-based fuzzy expert system was designed by four experts in diabetic neuropathy. The model variables were used to classify neuropathy in diabetic patients, defining it as mild, moderate, or severe. System performance was evaluated by means of the Kappa agreement measure, comparing the results of the model with those generated by the experts in an assessment of 50 patients. Accuracy was evaluated by an ROC curve analysis obtained based on 50 other cases; the results of those clinical assessments were considered to be the gold standard.

RESULTS

According to the Kappa analysis, the model was in moderate agreement with expert opinions. The ROC analysis (evaluation of accuracy) determined an area under the curve equal to 0.91, demonstrating very good consistency in classifying patients with diabetic neuropathy.

CONCLUSION

The model efficiently classified diabetic patients with different degrees of neuropathy severity. In addition, the model provides a way to quantify diabetic neuropathy severity and allows a more accurate patient condition assessment.

Forefoot plantar pressure reduction of off-the-shelf rocker bottom provisional footwear

BACKGROUND

Increased plantar pressures have been shown to be a risk factor in ulceration of the neuropathic foot. Prescriptive footwear is a common medical treatment, yet evidence regarding the efficacy of these prescriptions is underdeveloped. The purpose of this study is to determine the off-loading properties of four provisional shoes; a rocker sole compared to a flat sole shoe with and without the addition of a 1.25 cm plastizote insert.

METHODS

Fifteen subjects with peripheral neuropathy and a normal longitudinal arch were recruited to compare four types of provisional (post-operative) footwear. Plantar surface foot pressures were measured while wearing a rocker sole shoe or a flat stiff sole shoe. Both shoes were worn with and without a 1.25 cm plastizote insert. Peak plantar pressures were recorded for the hallux, metatarsal heads (1-5), midfoot, and heel.

FINDINGS

The rocker sole shoe with plastizote had the best off-loading properties. While wearing this footwear, mean peak plantar pressure was 2.8 kg/cm(2) (range: 1.7 to 4.5 kg/cm(2), 50% mean reduction from flat sole shoe without plastizote) and 1.9 kg/cm(2) (range: 0.7 to 3.6 kg/cm(2), 35% mean reduction) at the five metatarsal heads and hallux, respectively.

INTERPRETATION

For patients with a normal longitudinal arch and forefeet, either at risk of developing an ulcer or are healing a forefoot ulcer, a provisional shoe with a rocker sole and plastizote insole provides plantar pressure reduction of the forefoot. However, when results were analyzed for the subjects individually the amount of off-loading varied.

Comparison of hexahedral and tetrahedral elements in finite element analysis of the foot and footwear

Finite element analysis has been widely used in the field of foot and footwear biomechanics to determine plantar pressures as well as stresses and strains within soft tissue and footwear materials. When dealing with anatomical structures such as the foot, hexahedral mesh generation accounts for most of the model development time due to geometric complexities imposed by branching and embedded structures. Tetrahedral meshing, which can be more easily automated, has been the approach of choice to date in foot and footwear biomechanics. Here we use the nonlinear finite element program Abaqus (Simulia, Providence, RI) to examine the advantages and disadvantages of tetrahedral and hexahedral elements under compression and shear loading, material incompressibility, and frictional contact conditions, which are commonly seen in foot and footwear biomechanics. This study demonstrated that for a range of simulation conditions, hybrid hexahedral elements (Abaqus C3D8H) consistently performed well while hybrid linear tetrahedral elements (Abaqus C3D4H) performed poorly. On the other hand, enhanced quadratic tetrahedral elements with improved stress visualization (Abaqus C3D10I) performed as well as the hybrid hexahedral elements in terms of contact pressure and contact shear stress predictions. Although the enhanced quadratic tetrahedral element simulations were computationally expensive compared to hexahedral element simulations in both barefoot and footwear conditions, the enhanced quadratic tetrahedral element formulation seems to be very promising for foot and footwear applications as a result of decreased labor and expedited model development, all related to facilitated mesh generation.

The effect of shoe lacing on plantar pressure distribution and in-shoe displacement of the foot in healthy participants

AIMS

A proof of concept study to investigate the effect of shoe lacing on the plantar pressure distribution and in-shoe displacement of the foot during walking.

METHODS

Three randomized shoe-lacing conditions, which differed in lacing tightness (comfortable, loosened, and completely loose) were investigated in 20 healthy adults. On a 10-m walking test, plantar pressures were assessed with the Pedar(®)-X in-shoe measurement system. Perceived in-shoe displacement was scored on a numerical rating scale.

RESULTS

With respect to the pressure time integral statistically significant effects were found in the hallux, toes 2-5, first metatarsal head, and lateral midfoot regions. Post hoc comparison showed for the hallux: mean increase of 45.5 kPa s (95% confidence interval [CI]: 3.2-87.8 kPa s), and toes 2-5: mean increase of 23.5 kPa s (95% CI: 0.1-46.9 kPa s) between comfortably secured and completely loosened laces; lateral midfoot: mean decrease of -18.1 kPa s (95% CI: -31.5 to -4.8 kPa s) between comfortably secured and loosened laces. No significant effect was found on peak pressure, and average pressure. Participants reported a significant increase in heel slipping and in slipping back and forth of the foot as the laces were loosened.

CONCLUSIONS

Looser lacing techniques resulted in small peak and average plantar pressure changes (less than 3% and 6.5% respectively). Pressure time integral under the hallux and toes 2-5 increased 16.3% and 14.5% respectively, and perceived in-shoe displacement increased as compared to comfortably secured laces. These results suggest that diabetes patients should be advised to comfortably tighten their shoelaces during the whole day.

Off-loading the diabetic foot for ulcer prevention and healing

Retrospective and prospective studies have shown that elevated plantar pressure is a causative factor in the development of many plantar ulcers in diabetic patients and that ulceration is often a precursor of lower-extremity amputation. Herein, we review the evidence that relieving areas of elevated plantar pressure (off-loading) can prevent and heal plantar ulceration.There is no consensus in the literature concerning the role of off-loading through footwear in the primary or secondary prevention of ulcers. This is likely due to the diversity of intervention and control conditions tested, the lack of information about off-loading efficacy of the footwear used, and the absence of a target pressure threshold for off-loading. Uncomplicated plantar ulcers should heal in 6 to 8 weeks with adequate off-loading. Total-contact casts and other nonremovable devices are most effective because they eliminate the problem of nonadherence to recommendations for using a removable device. Conventional or standard therapeutic footwear is not effective in ulcer healing. Recent US and European surveys show that there is a large discrepancy between guidelines and clinical practice in off-loading diabetic foot ulcers. Many clinics continue to use methods that are known to be ineffective or that have not been proved to be effective while ignoring methods that have demonstrated efficacy.A variety of strategies are proposed to address this situation, notably the adoption and implementation of recently established international guidelines, which are evidence based and specific, by professional societies in the United States and Europe. Such an approach would improve the often poor current expectations for healing diabetic plantar ulcers.