Plantar soft-tissue thickness predicts high peak plantar pressure in the diabetic foot

Volumetric Analysis in Autologous Fat Grafting to the Foot

BACKGROUND

Pedal fat grafting is a safe, minimally invasive approach to treat pedal fat pad atrophy. Prior randomized controlled trials demonstrate that the fat as measured directly under the metatarsal heads disappears between 2 and 6 months after fat grafting, despite patients having relief for 2 years. The authors aim to use magnetic resonance imaging to further assess three-dimensional volume of fat in the foot after autologous fat grafting to help explain the mechanism for improved pain.

METHODS

A prospective study was performed using magnetic resonance imaging before and at 6 months after pedal fat grafting to assess changes in the three-dimensional morphology of the fat.

RESULTS

Seventeen patients (six men and 11 women) underwent injections with a mean volume of 5.8 cc per foot. At 6 months, patients demonstrated increased tissue thickness (p = 0.008) and volume (p = 0.04). Improvements were seen in pain (p < 0.05) and activity (p < 0.05). Foot pressures and forces were significantly decreased and positively correlated with increased fat pad volume (p < 0.05).

CONCLUSIONS

Pedal fat grafting significantly increases metatarsal fat pad volume. The distribution of the fat may contribute to lasting clinical relief in these patients.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Fat Grafting for Pedal Fat Pad Atrophy in a 2-Year, Prospective, Randomized, Crossover, Single-Center Clinical Trial

BACKGROUND

By age 60, 30 percent of Americans suffer from fat pad atrophy of the foot. Forefoot fat pad atrophy results from long-term aggressive activity, genetically dictated foot type, multiple forefoot steroid injections, surgery, and foot trauma.

METHODS

The authors present data from a 2-year, prospective, randomized crossover study performed to assess pain and disability indexes, fat pad thickness, forces, and pressures of stance and gait. Group 1 underwent fat grafting with 2 years of follow-up, and group 2 underwent conservative management for 1 year, then underwent fat grafting with 1 year of follow-up.

RESULTS

Eighteen subjects (14 women and four men) constituted group 1. Thirteen subjects (nine women and four men) constituted group 2. Group 1 reported the worst pain at baseline and group 2 experienced the worst pain at 6- and 12-month standard-of-care visits; pain for both groups improved immediately following fat grafting and lasted through study follow-up (p < 0.05). Group 1 demonstrated functional improvements at 12, 18, and 24 months postoperatively (p < 0.05), whereas group 2 demonstrated the highest function at 12 months postoperatively (p < 0.05). Pedal fat pad thickness of subjects in group 1 increased postoperatively and returned to baseline thickness at 2 months postoperatively; subjects in group 2 experienced return to baseline thickness at 6 months postoperatively (p < 0.01). Forces and pressures of stance and gait increased over the 2 years of follow-up for group 1 (p < 0.05).

CONCLUSION

Pedal fat grafting provides long-lasting improvements in pain and function, and prevents against worsening from conservative management.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, I.

The Influence of Fat Grafting on Skin Quality in Cosmetic Foot Grafting: A Randomized, Cross-Over Clinical Trial

BACKGROUND

Pedal fat grafting is a cosmetic procedure to treat the functional and aesthetic sequelae of pedal fat pad atrophy. Fat grafting has been found to mitigate these symptoms, but the exact mechanism is unknown.

OBJECTIVES

The authors hypothesized that pedal fat grafting may improve skin quality, accounting for prolonged symptomatic improvement despite loss of grafted fat.

METHODS

Patients with pedal atrophy were enrolled in a randomized crossover clinical trial. Group 1 underwent fat grafting upon enrollment with 2-year follow-up. Group 2 was managed conservatively for 1 year then placed into the fat grafting group with 1-year follow-up. Patients underwent pedal ultrasounds to determine thicknesses of the fat pad and dermis, and photographs were taken to assess skin quality.

RESULTS

Three men and 20 women with an average age of 63 ± 6 years and an average BMI of 26.0 ± 4.6 kg/m2 were enrolled in the study. Twenty-six feet were injected in Group 1 and 17 were injected in Group 2. Group 1 dermal thickness increased at 6 months post-injection (P < 0.05). This increase persisted through 24 months. Group 2 dermal thickness decreased prior to injection (P < 0.05) but returned to baseline after injection and through 12-month follow-up (P < 0.05). Fat pad thickness returned to baseline by study completion in both groups (P < 0.05).

CONCLUSIONS

Pedal fat grafting yielded a significant, sustained increase in dermal thickness, though grafted fat was not retained. Fat grafting may improve skin quality, which could contribute to improved clinical outcomes despite loss of grafted fat.

LEVEL OF EVIDENCE: 2

Autologous Fat Grafting for Pedal Fat Pad Atrophy: A Prospective Randomized Clinical Trial

BACKGROUND

Pedal fat pad atrophy is associated with pain, decreased tissue thickness, and increased foot pressures. To date, no objective studies investigating the use of fat grafting to the forefoot have been performed. The authors hypothesize that pedal fat grafting can reduce pain, increase tissue thickness, and decrease pedal pressures.

METHODS

A prospective randomized study was performed to assess tissue thickness, pain, and foot pressures. Group 1 underwent fat grafting immediately with 1-year follow-up, and group 2 underwent conservative management for 1 year.

RESULTS

Thirteen patients (two men and 11 women) constituted group 1 and 12 patients (four men and eight women) constituted group 2. Ten patients in group 1 underwent bilateral injections with a mean volume of 4.8 cc per foot. Mean follow-up time was 11.1 ± 5.4 months for group 1 and 13.8 ± 4.2 months for group 2. At 1 year, group 1 demonstrated improved foot function (p = 0.022), pain (p = 0.022), and work/leisure activities (p = 0.021). Group 1 had no change in tissue thickness, whereas in group 2, the right third metatarsal tissue thickness decreased significantly (p = 0.036). Foot pressures in group 1 did not improve; however, group 2 had a significant increase in left foot pressure (p = 0.011). When comparing the groups at 1 year, group 2 had significantly higher foot pressures and forces than group 1 (p < 0.05).

CONCLUSIONS

Pedal fat grafting significantly improves pain and disability outcomes, and prevents against worsening foot pressures. Future analysis will reveal whether fat grafting has lasting efficacy.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

Total contact cast wall load in patients with a plantar forefoot ulcer and diabetes

BACKGROUND

The total contact cast (TCC) is an effective intervention to reduce plantar pressure in patients with diabetes and a plantar forefoot ulcer. The walls of the TCC have been indirectly shown to bear approximately 30 % of the plantar load. A new direct method to measure inside the TCC walls with capacitance sensors has shown that the anterodistal and posterolateral-distal regions of the lower leg bear the highest load. The objective of this study was to directly measure these two regions in patients with Diabetes and a plantar forefoot ulcer to further understand the mechanism of pressure reduction in the TCC.

METHODS

A TCC was applied to 17 patients with Diabetes and a plantar forefoot ulcer. TCC wall load (contact area, peak pressure and max force) at the anterodistal and posterolateral-distal regions of the lower leg were evaluated with two capacitance sensor strips measuring 90 cm(2) (pliance®, novel GmbH, Germany). Plantar load (contact area, peak pressure and max force) was measured with a capacitance sensor insole (pedar®, novel GmbH, Germany) placed inside the TCC. Both pedar® and pliance® collected data simultaneously at a sampling rate of 50Hz synchronised to heel strike. The magnitude of TCC wall load as a proportion of plantar load was calculated. The TCC walls were then removed to determine the differences in plantar loading between the TCC and the cut down shoe-cast for the whole foot, rearfoot, midfoot and forefoot (region of interest).

RESULTS

TCC wall load was substantial. The anterodistal lower leg recorded 48 % and the posterolateral-distal lower leg recorded 34 % of plantar contact area. The anterodistal lower leg recorded 28 % and the posterolateral-distal lower leg recorded 12 % of plantar peak pressure. The anterodistal lower leg recorded 12 % and the posterolateral-distal lower leg recorded 4 % of plantar max force. There were significant differences in plantar load between the TCC and the cut down shoe-cast for the whole foot, rearfoot, midfoot and forefoot (region of ulcer). Contact area significantly increased by 5 % beneath the whole foot, 8 % at the midfoot and 6 % at the forefoot in the shoe-cast (p < 0.05). Peak pressure significantly increased by 8 % beneath the midfoot and 13 % at the forefoot in the shoe-cast (p < 0.05). Max force significantly increased 6 % beneath the midfoot in the (shoe-cast p < 0.05).

CONCLUSION

In patients with diabetes and a plantar forefoot ulcer, the walls of the TCC bear considerable load. Reduced plantar contact area in the TCC compared to the shoe-cast suggests that the foot is suspended by the considerable load bearing capacity of the walls of the TCC which contributes mechanically to the pressure reduction and redistribution properties of the TCC.

Plantar pressures, plantar forces, and their influence on the pathogenesis of diabetic foot ulcers: a review

BACKGROUND

Clinical recommendations for the prevention and healing of diabetic foot ulcers (DFUs) are somewhat clear. However, assessment and quantification of the mechanical stress responsible for DFU remain complex. Different pressure variables have been described in the literature to better understand plantar tissue stress exposure. This article reviews the role of pressure and shear forces in the pathogenesis of plantar DFU.

METHODS

We performed systematic searches of the PubMed and Embase databases, completed by a manual search of the selected studies. From 535 potentially relevant references, 70 studies were included in the full-text review.

RESULTS

Variables of plantar mechanical stress relate to vertical pressure, shear stress, and temporality of loading. At this time, in-shoe peak plantar pressure (PPP) is the only reliable variable that can be used to prevent DFU. Although it is a poor predictor of in-shoe PPP, barefoot PPP seems complementary and may be more suitable when evaluating patients with diabetes mellitus and peripheral neuropathy who seem noncompliant with footwear. An in-shoe PPP threshold value of 200 kPa has been suggested to prevent DFU. Other variables, such as peak pressure gradient and peak maximal subsurface shear stress and its depth, seem to be of additional utility.

CONCLUSIONS

To better assess the at-risk foot and to prevent ulceration, the practitioner should integrate quantitative models of dynamic foot plantar pressures, such as in-shoe and barefoot PPPs, with the regular clinical screening examination. Prospective studies are needed to evaluate causality between other variables of mechanical stress and DFUs.

Prevalence of standing plantar pressure distribution variation in north Asian Indian patients with diabetes mellitus: a study to understand ulcer formation

Diabetes Mellitus is a disorder of metabolism. Foot problems are common in diabetes and altered plantar pressures distribution may lead to ulceration in people with Diabetes Mellitus. Therefore the aim of this study was to investigate standing plantar pressure distribution variations in north Asian Indian diabetes mellitus subjects and its association with duration of diabetes. Thirty three subjects with age range from 40 to 75 years are recruited from AIIMS Endocrinology & metabolism lab Delhi, India and divided into three groups: 11 control subjects (non-diabetic), 11 diabetic subjects without neuropathy (DNN) and II diabetic subjects with neuropathy (DN). Neuropathy status was assessed by measuring loss of protective sensation to 10 gm Semen's Weinstein monofilament. Plantar pressure distributions parameter-Power ratio (PR) was measured during barefoot standing using portable PedoPowerGraph and results are analyzed using one way analysis of variance to detect significant difference between the groups. We found significant (p < 0.05; p < 0.01) difference in PR value between DN and CG groups in fore foot and hind foot but no significant (p > 0.05) difference in PR value was found between DNN and CG groups in the foot. As compared to DNN, DN group have maximum PR variations in the fore foot. Plantar pressure distribution parameter-PR was higher with longer duration of diabetes among type 2 diabetes subjects. In this study we conclude that plantar pressure distribution parameter-PR was able to distinguish the DN groups from the CG group in hind and fore foot during standing. Increased forefoot PR value is prevalent in the diabetic neuropathic subjects and may be responsible for the occurrence of foot sole ulcers but additional prospective studies are needed. In the future we will investigate the plantar pressure distribution parameter-PR variations in diabetes with obese and osteoarthritis subject.

DIABETES MELLITUS: ENQUIRY INTO ITS MEDICAL ASPECTS AND BIOENGINEERING OF ITS MONITORING AND REGULATION

Diabetes mellitus (DM) or hyperglycemia (in a more generalized term, high blood sugar) is a metabolic disorder that is now highly prevalent in the world population. Most of the food that people consume is converted into glucose, which enters the bloodstream following absorption–assimilation mechanisms. As a natural process, cells in our body utilize glucose for growth and energy. The glucose balance is maintained by a hormone called insulin that is secreted by the beta cells of pancreas. Hypotheses at the backdrop of DM occurrence are either (i) enough insulin is not produced and secreted resulting in increased level of glucose in blood, or (ii) insulin is insensitive to glucose, or (iii) insulin is non-targeted etc. If DM remains uncontrolled over time, it leads to serious damage to many of the body's systems, especially the nerves and blood vessels. This paper develops an enquiry into diabetes from many angles: (i) Diabetes as a disorder, its complications, causes, diagnostic tests, and treatment; (ii) Analysis of retinal and plantar images to characterize diabetes complications; (iii) How analysis of heart rate variability signals can depict diabetes; (iv) Biomedical engineering of the glucose–insulin regulatory system, and its employment in the modeling of the oral glucose tolerance test data, to detect diabetes as well as persons at risk of being diabetic; (v) Application of the glucose–insulin regulatory system to formulate an insulin delivery system for controlling blood sugar.

In-shoe Plantar Pressure Distribution in Nonneuropathic Type 2 Diabetic Patients in Singapore

BACKGROUND

We sought to establish the in-shoe plantar pressure distribution during normal level walking in type 2 diabetic patients of Chinese, Indian, and Malay descent without clinical evidence of peripheral neuropathy.

METHODS

Thirty-five patients with type 2 diabetes mellitus without loss of tactile sensation and foot deformities and 38 nondiabetic individuals in a control group had in-shoe plantar pressures collected. Maximum peak pressure and peak pressure-time integral of each foot were analyzed as separate variables and were masked into 13 areas. Differences in pressure variables were assessed by analysis of covariance, adjusting for relevant covariates at the 95% confidence interval.

RESULTS

No significant differences were noted in maximum peak pressures after adjusting for sex, race, age, height, and body mass. However, patients with diabetes mellitus had significantly higher mean ± SD pressure-time integrals at the right whole foot (309.50 ± 144.17 kPa versus 224.06 ± 141.70 kPa, P < .05) and first metatarsal (198.65 ± 138.27 kPa versus 121.54 ± 135.91 kPa, P < .05) masked areas than did those in the control group after adjustment.

CONCLUSIONS

Patients without clinical observable signs of foot deformity (implying absence of motor neuropathy) and sensory neuropathy had similar in-shoe maximum peak pressures as controls. This finding supported the notion that either component of neuropathy needs to be present before plantar pressures are elevated. Patients with diabetes mellitus demonstrated greater pressure-time integrals, implying that this variable might be the first clinical sign observable even before peripheral neuropathy could be tested.

COMPUTER-BASED IDENTIFICATION OF PLANTAR PRESSURE IN TYPE 2 DIABETES SUBJECTS WITH AND WITHOUT NEUROPATHY

Diabetes mellitus is a medical disorder characterized by varying or persistent hyperglycemia (elevated blood sugar levels), especially after eating. People with diabetes have problems converting food to energy. The most common form of diabetes is type 2 diabetes. Foot disease is a common complication of diabetes that can have tragic consequences. Abnormal plantar pressures are considered to play a major role in the pathologies of neuropathic ulcers in the diabetic foot. The purpose of this study was to classify the plantar pressure distribution in normal and type 2 diabetes subjects with and without neuropathy. Foot scans were obtained using the F-Scan (Tekscan, USA) in-shoe pressure measurement system. Various pedobarographic parameters such as the total plantar force, total contact area, peak pressures, and percentage medial impulse (PMI) were evaluated. These parameters were subjected to analysis of variance (ANOVA) test with a >95% confidence interval, giving excellent p-values in all of the categories. When these extracted parameters were presented to the artificial neural network (ANN) for classification, the neural network classifier was seen to be correct in more than 90% of the test cases.

Liquid silicone to mitigate plantar pedal pressure: a literature review

Disruption of the body's plantar fat pad can occur as a result of one of three mechanisms: simple fat pad atrophy associated with age-related degeneration, steroid use, or collagen vascular disease. Actual or relative displacement in to the underlying osseous prominences may be seen in association with structural deformity of the foot. Disease states such as diabetes may alter the normal structural integrity of soft tissues through nonenzymatic glycation leading to increased stiffness and thus reduced attenuating capacity. Fat pad atrophy, regardless of the cause, is often associated with substantial emotional, physical, productivity, and financial losses. In situations where the patient is sensate, the resultant skin on bone situation is extremely painful, especially when walking.

Preliminary investigation on the reduction of plantar loading pressure with different insole materials (SRP--Slow Recovery Poron, P--Poron, PPF--Poron +Plastazote, firm and PPS--Poron+Plastazote, soft)

BACKGROUND

The aim of this study is to investigate the amount of pressure reduction for different padding and insole materials commonly used in the podiatry clinic.

METHODS

Plantar pressure were taken for 5 subjects without insoles fitted (BF) in their daily sports shoes, and thereafter with 4 pairs of simple insoles (6.4 mm thick) each as follow: SRP - Slow Recovery Poron, P - Poron, PPF - Poron+Plastazote (firm) and PPS - Poron+Plastazote (soft). In addition, subjects were also tested with semi-compressed felt (SCF) padding with a 1st metatarsophalangeal joint (MTPJ) aperture cut-out bilaterally. Minimum, maximum, mean pressure and peak pressure at the hallux, 1st, 2nd, 3rd/4th and 5th MTPJ across both feet were analysed. Repeated measures ANOVA with post hoc Bonferroni paired wise comparison was used to test for any statistical significance at the 95% confidence level for all pressure data.

RESULTS

PPF was significant in reducing the minimum (p<0.005) and mean pressure (p<0.03) when compared to BF. This accounted for approximately 28% and 27% pressure reduction in minimum and mean pressure respectively. Peak pressure on the 1st MTPJ locality showed significant reduction of 37% and 29% with the use of SCF (p<0.004) and PPF (p<0.004), respectively.

CONCLUSIONS

All 4 commonly used insole materials were able to reduce pressure across the whole foot with PPF achieving significance. Off-loading the 1st MTPJ would still be best achieved with the commonly used plantar metatarsal pad of SCF with the aperture cut-out design.

Automated identification of diabetes type-2 subjects with and without neuropathy using eigenvalues

Diabetes is a disorder of metabolism and has been a leading healthcare burden throughout the world. The most typical form of diabetes is type-2 diabetes. It is commonly developed in adults of age 40 and older. The purpose of this study is to identify the plantar pressure distribution in normal subjects, diabetic type-2 subjects with neuropathy, and diabetic type-2 subjects without neuropathy. Foot scan images were obtained using the F-Scan (Tekscan USA) in-shoe measurement system. The eigenvalues were evaluated from principal-component analysis after performing continuous wavelets transformation (CWT). The eigenvalues of CWT in regions 5 and 7 had shown excellent p values of more than 95 per cent confidence level when subjected to an analysis-of-variance test. These parameters were then presented to an artificial neural network (ANN) and a Gaussian mixture model (GMM) for automatic classification. The results show that the ANN classifier performs better than the GMM and is able to identify the unknown class with a sensitivity of 100 per cent and a specificity of 72 per cent.

Prediction of peak pressure from clinical and radiological measurements in patients with diabetes

BACKGROUND

Various structural and functional factors of foot function have been associated with high local plantar pressures. The therapist focuses on these features which are thought to be responsible for plantar ulceration in patients with diabetes. Risk assessment of the diabetic foot would be made easier if locally elevated plantar pressure could be indicated with a minimum set of clinical measures.

METHODS

Ninety three patients were evaluated through vascular, orthopaedic, neurological and radiological assessment. A pressure platform was used to quantify the barefoot peak pressure for six forefoot regions: big toe (BT) and metatarsals one (MT-1) to five (MT-5). Stepwise regression modelling was performed to determine which set of the clinical and radiological measures explained most variability in local barefoot plantar peak pressure in each of the six forefoot regions. Comprehensive models were computed with independent variables from the clinical and radiological measurements. The difference between the actual plantar pressure and the predicted value was examined through Bland-Altman analysis.

RESULTS

Forefoot pressures were significant higher in patients with neuropathy, compared to patients without neuropathy for the whole forefoot, the MT-1 region and the MT-5 region (respectively 138 kPa, 173 kPa and 88 kPa higher: mean difference). The clinical models explained up to 39 percent of the variance in local peak pressures. Callus formation and toe deformity were identified as relevant clinical predictors for all forefoot regions. Regression models with radiological variables explained about 26 percent of the variance in local peak pressures. For most regions the combination of clinical and radiological variables resulted in a higher explained variance. The Bland and Altman analysis showed a major discrepancy between the predicted and the actual peak pressure values.

CONCLUSION

At best, clinical and radiological measurements could only explain about 34 percent of the variance in local barefoot peak pressure in this population of diabetic patients. The prediction models constructed with linear regression are not useful in clinical practice because of considerable underestimation of high plantar pressure values. Identification of elevated plantar pressure without equipment for quantification of plantar pressure is inadequate. The use of quantitative plantar pressure measurement for diabetic foot screening is therefore advocated.

Diabetic foot disorders. A clinical practice guideline (2006 revision)

The prevalence of diabetes mellitus is growing at epidemic proportions in the United States and worldwide. Most alarming is the steady increase in type 2 diabetes, especially among young and obese people. An estimated 7% of the US population has diabetes, and because of the increased longevity of this population, diabetes-associated complications are expected to rise in prevalence. Foot ulcerations, infections, Charcot neuroarthropathy, and peripheral arterial disease frequently result in gangrene and lower limb amputation. Consequently, foot disorders are leading causes of hospitalization for persons with diabetes and account for billion-dollar expenditures annually in the US. Although not all foot complications can be prevented, dramatic reductions in frequency have been achieved by taking a multidisciplinary approach to patient management. Using this concept, the authors present a clinical practice guideline for diabetic foot disorders based on currently available evidence, committee consensus, and current clinical practice. The pathophysiology and treatment of diabetic foot ulcers, infections, and the diabetic Charcot foot are reviewed. While these guidelines cannot and should not dictate the care of all affected patients, they provide evidence-based guidance for general patterns of practice. If these concepts are embraced and incorporated into patient management protocols, a major reduction in diabetic limb amputations is certainly an attainable goal.

The diabetic foot: from art to science. The 18th Camillo Golgi lecture

Diabetic foot ulceration represents a major medical, social and economic problem all over the world. While more than 5% of diabetic patients have a history of foot ulceration, the cumulative lifetime incidence may be as high as 15%. Ethnic differences exist in both ulcer and amputation incidences, with both being less common in patients of Indian subcontinent origin living in the UK. Foot ulceration results from the interaction of several contributory factors, the most important of which is neuropathy. With respect to the management of acute Charcot neuroarthropathy in diabetes, recent studies suggest that bisphosphonates reduce disease activity as judged not only by differences in skin temperature, but also by assessing markers of bone turnover. The use of the total-contact cast is demonstrated in the treatment of acute Charcot feet and of plantar neuropathic ulcers. Histological evidence suggests that pressure relief results in chronic foot ulcers changing their morphological appearance by displaying some features of an acute wound. Thus, repetitive stresses on the insensate foot appear to play a major role in maintaining ulcer chronicity. It is hoped that increasing research activity in foot disease will ultimately result in fewer ulcers and less amputation in diabetes.