Muscle and Joint Factors Associated With Forefoot Deformity in the Diabetic Neuropathic Foot

Use of computed tomography to identify muscle quality subgroups, spatial mapping, and preliminary relationships to function in those with diabetic peripheral neuropathy

BACKGROUND

Decreased muscle volume and increased muscle-associated adipose tissue (MAAT, sum of intra and inter-muscular adipose tissue) of the foot intrinsic muscle compartment are associated with deformity, decreased function, and increased risk of ulceration and amputation in those with diabetic peripheral neuropathy (DPN).

RESEARCH QUESTION

What is the muscle quality (normal, abnormal muscle, and adipose volumes) of the DPN foot intrinsic compartment, how does it change over time, and is muscle quality related to gait and foot function?

METHODS

Computed tomography was performed on the intrinsic foot muscle compartment of 45 subjects with DPN (mean age: 67.2 ± 6.4 years) at baseline and 3.6 years. Images were processed to obtain volumes of MAAT, highly abnormal, mildly abnormal, and normal muscle. For each category, annual rates of change were calculated. Paired t-tests compared baseline and follow-up. Foot function during gait was assessed using 3D motion analysis and the Foot and Ankle Ability Measure. Correlations between muscle compartment and foot function during gait were analyzed using Pearson's correlations.

RESULTS

Total muscle volume decreased, driven by a loss of normal muscle and mildly abnormal muscle (p<0.05). MAAT and the adipose-muscle ratio increased. At baseline, 51.5% of the compartment was abnormal muscle or MAAT, increasing to 55.0% at follow-up. Decreased total muscle volume correlated with greater midfoot collapse during gait (r = -0.40, p = 0.02). Greater volumes of highly abnormal muscle correlated with a lower FAAM score (r = -0.33, p = 0.03).

SIGNIFICANCE

Muscle volume loss may progress in parallel with MAAT accumulation, impacting contractile performance in individuals with DPN. Only 48.5% of the DPN intrinsic foot muscle compartment consists of normal muscle and greater abnormal muscle is associated with worse foot function. These changes identify an important target for rehabilitative intervention to slow or prevent muscle deterioration and poor foot outcomes.

Plantar pressure reduction in the heel region through self-adjusting insoles with a heel cup in standard and individualized rocker shoes

BACKGROUND

Effectiveness of therapeutic footwear in reducing peak pressure in persons with diabetes and loss of protective sensation to prevent diabetic foot ulcers varies due to manual production and possible changing foot structure. A previous two-way approach to address this issue, featuring individualized 3D-printed rocker midsoles and self-adjusting insoles, proved effective in the forefoot but less in the heel. To address this, new insoles incorporating a heel cup are developed.

METHODS

In-shoe pressure was measured, while persons with diabetes and loss of protective sensation with high peak pressure (≥ 200 kPa) in the heel walked on a treadmill with control and individualized rocker shoe paired with control and new insole.

FINDINGS

Generalized estimating equations revealed significant decrease in peak pressure in the proximal heel with the new insole alone and combined with rocker shoe compared to rocker shoe alone. For the distal heel, significant decrease in peak pressure is shown with the combination of new insole and rocker shoe compared to control shoe. For the forefoot and toes (excluding hallux) significant decrease in peak pressure is shown using the rocker shoe alone or combined with the heel cup compared to control shoe.

INTERPRETATION

The new insole paired with rocker shoe is effective in reducing peak pressure in the distal heel. To have similar (or more) success in proximal heel, one could replace the rocker midsole with more compliant materials. The rocker shoe used separately or combined with a heel cup effectively reduces the peak pressure in the forefoot and other toes.

When, where, and why should we look for vestibular dysfunction in people with diabetes mellitus?

The biochemistry of diabetes mellitus results in multi-system tissue compromise that reduces functional mobility and interferes with disease management. Sensory system compromise, such as peripheral neuropathy and retinopathy, are specific examples of tissue compromise detrimental to functional mobility. There is lack of clarity regarding if, when, and where parallel changes in the peripheral vestibular system, an additional essential sensory system for functional mobility, occur as a result of diabetes. Given the systemic nature of diabetes and the plasticity of the vestibular system, there is even less clarity regarding if potential vestibular system changes impact functional mobility in a meaningful fashion. This commentary will provide insight as to when we should employ diagnostic vestibular function tests in people with diabetes, where in the periphery we should look, and why testing may or may not matter. The commentary concludes with recommendations for future research and clinical care.

Correlation analysis between foot deformity and diabetic foot with radiographic measurement

Background

Foot deformity is a risk factor for diabetic foot ulcer. This study was aimed to investigate the relationship between hallux valgus (HV) and diabetic foot through the radiographic measurement.

Methods

The patients with diabetic foot hospitalizing in the Department of Endocrinology, the First Affiliated Hospital of Chongqing Medical University from September 2016 to June 2020 were selected. Then the foot plain X-ray radiographs were completed, and the size of HV angle (HVA) was measured. Their clinical data were collected, and the ulcer recurrence rate, amputation rate and mortality rate of the patients were followed up.

Results

A total of 370 patients were included. According to HVA, patients were divided into non-HV group (HVA<15°), and mild (15°≤HVA ≤ 20°), moderate (20°40°) HV groups. The age, height, BMI, smoking history and glycosylated hemoglobin level among the non-HVA, mild, moderate, and severe HV group (P<0.05), while smoking history, HbA1c, eGFR and autonomic neuropathy were significantly lower in HV group than those in non-HV group (P<0.05). The ulcer area in patients with moderate HV was larger than that in non-HV patients, and the severity of infection in patients with severe HV was significantly higher than that the other three groups (P<0.05).

Conclusion

The occurrence of HV is not only related to age and BMI, but also to the creatinine and eGFR level, autonomic neuropathy, lower limb arteriosclerosis occlusion, coronary heart disease and hypertension. Therefore, more attention should be paid to renal function screening, neuropathy screening and evaluation of lower extremity vascular lesions in patients with diabetes, especially those with moderate or higher HV.

Adverse health correlates of intimate partner violence against older women: Mining electronic health records

Intimate partner violence (IPV) is often studied as a problem that predominantly affects younger women. However, studies show that older women are also frequently victims of abuse even though the physical effects of abuse are harder to detect. In this study, we mined the electronic health records (EHR) available through IBM Explorys to identify health correlates of IPV that are specific to older women. Our analyses suggested that diagnostic terms that are co-morbid with IPV in older women are dominated by substance abuse and associated toxicities. When we considered differential co-morbidity, i.e., terms that are significantly more associated with IPV in older women compared to younger women, we identified terms spanning mental health issues, musculoskeletal issues, neoplasms, and disorders of various organ systems including skin, ears, nose and throat. Our findings provide pointers for further investigation in understanding the health effects of IPV among older women, as well as potential markers that can be used for screening IPV.

Effect of Diabetes on Tendon Structure and Function: Not Limited to Collagen Crosslinking

Diabetes mellitus (DM) is associated with musculoskeletal complications-including tendon dysfunction and injury. Patients with DM show altered foot and ankle mechanics that have been attributed to tendon dysfunction as well as impaired recovery post-tendon injury. Despite the problem of DM-related tendon complications, treatment guidelines specific to this population of individuals are lacking. DM impairs tendon structure, function, and healing capacity in tendons throughout the body, but the Achilles tendon is of particular concern and most studied in the diabetic foot. At macroscopic levels, asymptomatic, diabetic Achilles tendons may show morphological abnormalities such as thickening, collagen disorganization, and/or calcific changes at the tendon enthesis. At smaller length scales, DM affects collagen sliding and discrete plasticity due to glycation of collagen. However, how these alterations translate to mechanical deficits observed at larger length scales is an area of continued investigation. In addition to dysfunction of the extracellular matrix, tendon cells such as tenocytes and tendon stem/progenitor cells show significant abnormalities in proliferation, apoptosis, and remodeling capacity in the presence of hyperglycemia and advanced glycation end-products, thus contributing to the disruption of tendon homeostasis and healing. Improving our understanding of the effects of DM on tendons-from molecular pathways to patients-will progress toward targeted therapies in this group at high risk of foot and ankle morbidity.

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.

Computed Tomography and Magnetic Resonance Correlation and Agreement for Foot Muscle and Adipose Tissue Measurements

BACKGROUND

Volumetric measures of intrinsic foot muscle and intermuscular adipose tissue (IMAT) infiltration are important in understanding foot injury and disease. We questioned whether measures of muscle and fat derived from computed tomography (CT) and magnetic resonance (MR) would be comparable.

METHODS

This study determined the correlation and level of agreement between CT and MR measurements of foot muscle and IMAT from 32 subjects with diabetes and peripheral neuropathy. Volumetric CT and DIXON 3T MR scans were obtained. Intermuscular adipose tissue and muscle volumes used to create the IMAT to muscle ratio were obtained by segmenting the forefoot muscle compartment from each modality.

RESULTS

Computed tomography IMAT ratios were significantly correlated (r = 0.85, P < 0.0001) with MR IMAT ratios. Computed tomography and MR IMAT ratio mean difference between CT and MR was small (0.044 unit, Bland-Altman plots).

CONCLUSIONS

The CT and MR IMAT ratio measurements were highly correlated, indicating both modalities represent tissue quantification similarly.Level of Evidence: 2Technical Efficacy: 1.

A limited number of slices yields comparable results to all slices in foot intrinsic muscle deterioration ratio on computed tomography and magnetic resonance imaging

Diagnostic imaging modalities, like computed tomography (CT) and magnetic resonance imaging (MRI), can be used to assess in vivo muscle quality. Quantitative assessment using these techniques is time-intensive and costly due in part to extensive post-processing needs. The purpose of this study was to identify whether a subset of slices on CT and MRI would yield comparable results to the full number of slices for a measure of muscle quality (muscle deterioration ratio = fat volume/muscle volume) in the foot intrinsic muscles of people with diabetes and peripheral neuropathy. CT (0.6 mm slice thickness) and MRI (3.5 mm slice thickness) scans were obtained using previously described methods. The total number of slices acquired during the scan was compared to several conditions using a portion of slices. Bland-Altman plots and Lin's concordance correlation coefficient were used to test agreement. Any condition using at least three slices yielded substantial to almost perfect agreement with the total number of slices on both CT and MRI (Range of Lin's concordance correlation coefficient: 0.947-0.999). Using a single slice in the middle of the region of interest demonstrated poor to moderate agreement with the total number of slices. The findings of this study suggest that using a limited number of slices to quantify muscle deterioration ratio on CT or MRI is a viable way to balance the combined need for measurement accuracy with feasibility in research and clinical settings.

Lower extremity MRI following 10-week supervised exercise intervention in patients with diabetic peripheral neuropathy

INTRODUCTION

The purpose of this study was to characterize using MRI the effects of a 10-week supervised exercise program on lower extremity skeletal muscle composition, nerve microarchitecture, and metabolic function in individuals with diabetic peripheral neuropathy (DPN).

RESEARCH DESIGN AND METHODS

Twenty participants with DPN completed a longitudinal trial consisting of a 30-day control period, during which subjects made no change to their lifestyle, followed by a 10-week intervention program that included three supervised aerobic and resistance exercise sessions per week targeting the upper and lower extremities. The participants' midcalves were scanned with multinuclear MRI two times prior to intervention (baseline₁ and baseline₂) and once following intervention to measure relaxation times (T1, T1ρ, and T2), phosphocreatine recovery, fat fraction, and diffusion parameters.

RESULTS

There were no changes between baseline₁ and baseline₂ MRI metrics (p>0.2). Significant changes (p<0.05) between baseline₂ and postintervention MRI metrics were: gastrocnemius medialis (GM) T1 -2.3%±3.0% and soleus T2 -3.2%±3.1%. Trends toward significant changes (0.05<p<0.1) between baseline₂ and postintervention MRI metrics were: calf adipose infiltration -2.6%±6.4%, GM T1ρ -4.1%±7.7%, GM T2 -3.5%±6.4%, and gastrocnemius lateral T2 -4.6±7.4%. Insignificant changes were observed in gastrocnemius phosphocreatine recovery rate constant (p>0.3) and tibial nerve fractional anisotropy (p>0.6) and apparent diffusion coefficient (p>0.4).

CONCLUSIONS

The 10-week supervised exercise intervention program successfully reduced adiposity and altered resting tissue properties in the lower leg in DPN. Gastrocnemius mitochondrial oxidative capacity and tibial nerve microarchitecture changes were not observed, either due to lack of response to therapy or to lack of measurement sensitivity.

A Meta-Analysis of the Outcomes of Resection Arthroplasty for Resistant Hallucal Diabetic Ulcers

The standard medical care (SC) of non-infected diabetic foot ulcers (DFUs) has been reported to yield varying rates of wound healing with high recurrence rate in non-infected wounds. Conservative surgery has been advanced as an alternative to SC in treating resistant non-complicated and complicated DFUs. Studies reporting resection arthroplasty (RA) of the first metatarsal head stated high healing rates with less recurrence. The aim of this meta-analysis is to quantitatively assess the efficacy of the RA procedure. Based on 9 included studies (3 case-control and 6 case-series) with 225 patients (244 feet, 244 hallucal plantar ulcers) and a mean follow-up period was of 22.8 ±13.3 months, the weighted estimates of comparative studies (RA vs. SC) were as follows: healing rate (100% vs. 79.9%, p = .0001), time to heal (3.3 ±0.28 vs. 8.4 ±1.5 weeks, p = .002), recurrence rate (5.7% vs. 25.4%, p = .001) and transfer rate (4.5% vs. 1.4%, p = .1). Similar values were found when analyzing case-series of non-infected and infected wounds treated with RA. Based on the available evidence, resection arthroplasty of the first ray is to be considered an effective conservative surgery in treating resistant or complicated hallucal neuropathic ulcers. Further prospective controlled trials are warranted to validate the review findings.

Simple model of arch support: Relevance to Charcot Neuroarthropathy

BACKGROUND

Charcot neuropathy is a common complication resulting from poorly controlled diabetes and peripheral neuropathy leading to the collapse, and ultimately the breakdown, of the midfoot. Mechanically, it is likely that a compromised arch support in this, or any other patient group that experiences foot flattening, would be associated with slippage at the distal and proximal interface regions of the plantar surface of the foot and the adjacent support surface. This slippage, although difficult to quantify with standard motion capture systems used in a gait laboratory, could potentially be assessed with systems for monitoring interface shear stresses. However, before investing in such systems, a correlation between arch flattening and interface shear stresses needs to be verified.

METHODS

For this purpose, a sagittal plane model of a foot was developed using a multi-body dynamics package (MSC Adams). This model mimicked a subject swaying back and forth, and was constructed to show the dependence of interface stresses on altered arch support.

FINDINGS

The model's predictions matched typical FootSTEPS data: lengthening of the arch of 1-2 mm, sway oscillations of 0.22-0.33 s and frictional force differences (calcaneus relative to forefoot) of 60 N. Of clinical relevance, when the stiffness of the plantar spring (representing aponeurosis and intrinsic muscles) was reduced by 10%, the frictional force difference increased by about 6.5%.

INTERPRETATION

The clinical implications of this study are that, while arch lengthening of less than 2 mm might be difficult to measure reliably in a gait lab, using shear sensors under the forefoot and hindfoot should allow arch support to be assessed in a repeatable manner.

Deteriorated regional calf microcirculation measured by contrast-free MRI in patients with diabetes mellitus and relation with physical activity

OBJECTIVE

To evaluate regional calf muscle microcirculation in people with diabetes mellitus (DM) with and without foot ulcers, compared to healthy control people without DM, using contrast-free magnetic resonance imaging methods.

METHODS

Three groups of subjects were recruited: non-DM controls, DM, and DM with foot ulcers (DM + ulcer), all with ankle brachial index (ABI) > 0.9. Skeletal muscle blood flow (SMBF) and oxygen extraction fraction (SMOEF) in calf muscle were measured at rest and during a 5-min isometric ankle plantarflexion exercise. Subjects completed the Yale physical activity survey.

RESULTS

The exercise SMBF (ml/min/100 g) of the medial gastrocnemius muscle were progressively impaired: 63.7 ± 18.9 for controls, 42.9 ± 6.7 for DM, and 36.2 ± 6.2 for DM + ulcer, p < 0.001. Corresponding exercise SMOEF was the lowest in DM + ulcers (0.48 ± 0.09). Exercise SMBF in the soleus muscle was correlated moderately with the Yale physical activity survey (r = 0.39, p < 0.01).

CONCLUSIONS

Contrast-free MR imaging identified progressively impaired regional microcirculation in medial gastrocnemius muscles of people with DM with and without foot ulcers. Exercise SMBF in the medial gastrocnemius muscle was the most sensitive index and was associated with HbA1c. Lower exercise SMBF in the soleus muscle was associated with lower Yale score.

Association of toe-extension movement pattern magnitude and variability during three functional tasks with diabetic foot complications

BACKGROUND

A toe-extension movement pattern may contribute to metatarsophalangeal joint deformity and ulceration in people with diabetes. We sought to quantify the relationship between toe extension magnitude and variability during three functional tasks (ankle range of motion, sit to stand, walking) with metatarsophalangeal joint deformity, and identify potential mechanisms associated with a toe-extension movement pattern.

METHODS

Individuals with diabetes and peripheral neuropathy were included (n = 60). Metatarsophalangeal joint deformity was assessed using computed tomography (CT). Toe-extension movement was quantified using 3-dimensional motion capture. Linear regression was used to investigate the role of toe-extension movement pattern on metatarsophalangeal joint deformity. Regression analysis was used to identify mechanisms (neuropathy severity, foot intrinsic muscle deterioration ratio, ankle dorsiflexion range of motion) contributing to toe-extension movement pattern.

FINDINGS

Toe extension with each functional task as well as the mean and coefficient of variation across all tasks were significantly related to metatarsophalangeal joint deformity (range of correlation coefficients = (-0.386, 0.692), p ≤ 0.001). Ankle dorsiflexion range of motion was associated with mean toe extension across all tasks (r_sp = -0.282, p = 0.029). Neuropathy severity and foot intrinsic muscle deterioration ratio were associated with toe extension variability (r_sp = -0.373, p = 0.003 and r_sp = -0.266, p = 0.043; respectively).

INTERPRETATION

Greater magnitude and lower variability of a toe-extension movement pattern was found to be associated with metatarsophalangeal joint deformity. These findings may support clinical assessment and treatment of movement across more than one task.

Foot deformities in patients with diabetic mellitus (with and without peripheral neuropathy)

BACKGROUND

Diabetic peripheral neuropathy (DPN) is one of the most common complications in diabetes mellitus. It is the disorder that most commonly affects the feet of people with diabetes. The aim of the present study is to determine the relationship between DPN and the presence of deformities in the foot.

MATERIAL AND METHODS

A descriptive observational study was conducted of 111 patients diagnosed with Diabetes Mellitus (DM) type 1 or 2. All participants were aged at least 18 years and were previously informed in detail about the aims and procedures of the study.

RESULTS

Regarding the presence of DPN, the only significant relationships were found for the right foot with the deformity of the second toe (claw, hammer or mallet) (p = 0.017, OR 0.29 [0.10-0.83]) and for the left foot with the deformity of the second toe (p = 0.048; OR: 0.37 [0.14-1.01]), third toe (p = 0.012; OR: 0.29 [0.11-0.79]) and the presence of hallux extensus (p = 0.05; OR: 8.27 [1.05-64.98]).

CONCLUSIONS

A significant number of foot deformities were observed among these patients with DM, regardless of the presence of DPN. These deformities should be carefully evaluated in order to determine the most appropriate treatment at an early stage, which will reduce the risk of ulceration. Although it should be use with caution to be transferrable to the general population with peripheral neuropathy.

A Meta-Analysis of the Outcomes of Metatarsal Head Resection for the Treatment of Neuropathic Diabetic Foot Ulcers

Significance: Diabetic foot ulcers (DFUs) are associated with high morbidity, mortality, and health costs. Standard care (SC) associated with nonsurgical offloading is the mainstay treatment for DFUs, but it has high recurrence and infection rates. Metatarsal head resection (MHR) has been proposed as an effective surgical offloading technique for the treatment of plantar neuropathic DFUs, but with no evidence synthesis yet. Recent Advances: Based on PRISMA guidelines, a meta-analysis was conducted to assess the efficacy of MHR. Four electronic databases were searched for. Eleven studies met the inclusion criteria with a total of 477 patients (494 feet and 593 neuropathic forefoot ulcers). The studies included three retrospective comparative studies and eight case series. Critical Issues: Meta-analytical results of comparative studies on recent noninfected DFUs showed MHR having significantly better rates of healing, time to healing, ulcer recurrence, and infection than SC. Failure to heal, recurrence, and infection rates were 4 times higher in the SC group than in the MHR group, and the amputation rate was two times higher in the SC group than in the MHR group. The outcomes of the meta-analysis of case series on chronic and recalcitrant ulcers treated with MHR were similar. Future Directions: Considering the natural history of DFUs treated conservatively and the satisfactory outcomes with a significantly low complication rate of MHR, physicians should consider the use of MHR more often and include this technique in the early management of DFUs. Scope and Significance: DFU impose great public health burden around the globe. Standard of care using in-office debridement and topical agents is the usual mainstay of treatment. However, such conservative care is known to result in high rates of ulcer recurrence and complications. In this systematic review, we quantitatively investigate the outcomes of a surgical off-loading technique, the MHR in the treatment of chronic plantar neuropathic wounds. Translational Relevance: Many biochemical factors are implicated in the complex process of wound healing. In the case of diabetic neuropathic ulcers of the forefoot, additional mechanical factors induced by the presence of diabetic neuropathy lead to high pressure loads of the metatarsal heads on the plantar skin. With time, such chronic loads could favor ulcer formation. Removal of the causal mechanical factor could alleviate the pressure and allow wound healing. Clinical Relevance: Neuropathic plantar ulcers are difficult-to-heal wounds and chronicity is associated to frequent hospitalizations, higher rates of amputation, and mortality. Early removal of the indirect causal agent, the resection of the metatarsal head, after failure of a well-conducted conservative standard of care could be a needed solution for wound healing and consequently a potential for reducing complications and costs.

Neuropathy, claw toes, intrinsic muscle volume, and plantar aponeurosis thickness in diabetic feet

BACKGROUND

The objective of this study was to explore the relationships between claw toe deformity, peripheral neuropathy, intrinsic muscle volume, and plantar aponeurosis thickness using computed tomography (CT) images of diabetic feet in a cross-sectional analysis.

METHODS

Forty randomly-selected subjects with type 2 diabetes were selected for each of the following four groups (n = 10 per group): 1) peripheral neuropathy with claw toes, 2) peripheral neuropathy without claw toes, 3) non-neuropathic with claw toes, and 4) non-neuropathic without claw toes. The intrinsic muscles of the foot were segmented from processed CT images. Plantar aponeurosis thickness was measured in the reformatted sagittal plane at 20% of the distance from the most inferior point of the calcaneus to the most inferior point of the second metatarsal. Five measurement sites in the medial-lateral direction were utilized to fully characterize the plantar aponeurosis thickness. A linear mixed-effects analysis on the effects of peripheral neuropathy and claw toe deformity on plantar aponeurosis thickness and intrinsic muscle volume was performed.

RESULTS

Subjects with concurrent neuropathy and claw toes had thicker mean plantar aponeurosis (p < 0.006) and may have had less mean intrinsic muscle volume (p = 0.083) than the other 3 groups. The effects of neuropathy and claw toes on aponeurosis thickness were synergistic rather than additive. A similar pattern may exist for intrinsic muscle volume, but results were not as conclusive. A negative correlation was observed between plantar aponeurosis thickness and intrinsic muscle volume (R² = 0.323, p < 0.001).

CONCLUSIONS

Subjects with concurrent neuropathy and claw toe deformity were associated with the smallest intrinsic foot muscle volumes and the thickest plantar aponeuroses. Intrinsic muscle atrophy and plantar aponeurosis thickening may be related to the development of claw toes in the presence of neuropathy.

Surgery Versus Nonsurgical Methods in Treating Neuropathic Plantar Forefoot Ulcers: A Meta-Analysis of Comparative Studies

The treatment of diabetic foot ulcers (DFUs) is usually based on local debridement, topical agents, and nonsurgical off-loading. When compared with nonsurgical methods, a number of articles reported better results with surgery. The aim of this meta-analysis was to collate quantitative evidence on the outcomes of surgery versus nonsurgical treatment (NST) of DFUs. Databases were searched from inception to September 2019. PRISMA guidelines were followed, and the Joanna Briggs Institute critical appraisal tools were used to appraise studies' quality. Nine studies were included totalizing 436 ulcers (216 treated with surgery and 220 DFUs with NST). The primary outcome was the healing rate. The secondary outcomes were time to heal, recurrence rate, transfer rate, infection rate, and amputation/revision surgery rate. The risk differences (RDs) between the healing rates following surgery and NST for infected and noninfected ulcers were 17% (95% confidence interval [CI] = 0.012-0.328, P = .03) and 19.2% (95% CI = 0.050-0.334, P = .008), respectively, in favor of surgery. The amputation/revision surgery rate was significantly better following surgery for both types of ulcers. Noninfected ulcers demonstrated significantly lesser time to heal, recurrence, and infection rates following surgery. This meta-analysis demonstrated that surgery was superior to NST in treating infected and noninfected neuropathic plantar wounds.

Skeletal Muscle Regeneration in Advanced Diabetic Peripheral Neuropathy

BACKGROUND

Decreased lean muscle mass in the lower extremity in diabetic peripheral neuropathy (DPN) is thought to contribute to altered joint loading, immobility, and disability. However, the mechanism behind this loss is unknown and could derive from a reduction in size of myofibers (atrophy), destruction of myofibers (degeneration), or both. Degenerative changes require participation of muscle stem (satellite) cells to regenerate lost myofibers and restore lean mass. Determining the degenerative state and residual regenerative capacity of DPN muscle will inform the utility of regeneration-targeted therapeutic strategies.

METHODS

Biopsies were acquired from 2 muscles in 12 individuals with and without diabetic neuropathy undergoing below-knee amputation surgery. Biopsies were subdivided for histological analysis, transcriptional profiling, and satellite cell isolation and culture.

RESULTS

Histological analysis revealed evidence of ongoing degeneration and regeneration in DPN muscles. Transcriptional profiling supports these findings, indicating significant upregulation of regeneration-related pathways. However, regeneration appeared to be limited in samples exhibiting the most severe structural pathology as only extremely small, immature regenerated myofibers were found. Immunostaining for satellite cells revealed a significant decrease in their relative frequency only in the subset with severe pathology. Similarly, a reduction in fusion in cultured satellite cells in this group suggests impairment in regenerative capacity in severe DPN pathology.

CONCLUSION

DPN muscle exhibited features of degeneration with attempted regeneration. In the most severely pathological muscle samples, regeneration appeared to be stymied and our data suggest that this may be partly due to intrinsic dysfunction of the satellite cell pool in addition to extrinsic structural pathology (eg, nerve damage).

CLINICAL RELEVANCE

Restoration of DPN muscle function for improved mobility and physical activity is a goal of surgical and rehabilitation clinicians. Identifying myofiber degeneration and compromised regeneration as contributors to dysfunction suggests that adjuvant cell-based therapies may improve clinical outcomes.

Multi-System Factors Associated with Metatarsophalangeal Joint Deformity in Individuals with Type 2 Diabetes

The underlying factors contributing to metatarsophalangeal joint deformity, a known precursor to skin breakdown in individuals with diabetes mellitus (DM), is likely to involve multiple body systems. The purpose of this cross-sectional study was to identify multi-system factors associated with metatarsophalangeal joint deformity in individuals with type 2 DM and peripheral neuropathy (n = 60). Metatarsophalangeal joint deformity was quantified with a computed tomography (CT) scan. System biomarkers included the musculoskeletal system (foot intrinsic muscle deterioration, tarsal/metatarsal bone mineral density, ankle dorsiflexion, metatarsophalangeal extension movement during a sit to stand task); the vascular system (ankle-brachial index); and the endocrine/immune systems (high sensitivity C-reactive protein, skin intrinsic fluorescence, and hemoglobin A1C). Muscle deterioration (r = 0.27), bone density (r = -0.35), metatarsophalangeal extension movement (r = 0.50), maximum dorsiflexion (r = -0.31), and ankle-brachial index (r = 0.33) were related to metatarsophalangeal joint deformity (p < 0.05). Bone mineral density and metatarsophalangeal extension movement were retained in a regression model relating to deformity (R2 = 0.34). All musculoskeletal system biomarkers and the ankle-brachial index demonstrated weak to moderate relationships to metatarsophalangeal joint deformity. Bone mineral density of the tarsal/metatarsal bones and extending the toes during a sit to stand task were the two strongest factors associated with metatarsophalangeal joint deformity. Evaluation and management of foot bone mineral density and toe extension movement pattern could reduce metatarsophalangeal joint deformity and the risk of skin breakdown and subsequent amputation.

The Role of Physical Therapists in Fighting the Type 2 Diabetes Epidemic

BACKGROUND

In 2014, the total prevalence of diabetes was estimated to be 422 million people worldwide. Due to the aging population and continued increase in obesity rates, the prevalence is expected to rise to 592 million by 2035. Diabetes can lead to several complications, including cardiovascular disease, stroke, peripheral arterial disease, nephropathy, neuropathy, retinopathy, lower extremity amputation, and musculoskeletal impairments.

CLINICAL QUESTION

Up to 80% of patients referred for outpatient physical therapy have diabetes or are at risk for diabetes, providing an opportunity for physical therapists to intervene. Therefore, we asked, "What is the role of physical therapists in fighting the diabetes epidemic?"

KEY RESULTS

Physical therapists commonly prescribe physical activity for the treatment of diabetes and other chronic diseases, such as cardiovascular disease and osteoarthritis. Physical therapists may also screen for risk factors for diabetes and diabetes-related complications and modify traditional musculoskeletal exercise prescription accordingly. Physical therapists must advocate for regular physical activity as a key component of the treatment of chronic diseases in all patient interactions.

CLINICAL APPLICATION

This commentary (1) describes the diabetes epidemic and the health impact of diabetes and diabetes-related complications, (2) highlights the physical therapist's role as front-line provider, and (3) provides recommendations for physical therapists in screening for diabetes risk factors and diabetes-related complications and considerations for patient management. We focus on type 2 diabetes. J Orthop Sports Phys Ther 2020;50(1):5-16. Epub 28 Nov 2019. doi:10.2519/jospt.2020.9154.

Surface electromyography of the foot: A protocol for sensor placement

BACKGROUND

The use of surface EMG (sEMG) to record muscle activity is common place yet due to restrictions in technology studies on the intrinsic foot muscles have been limited or only fine wire instruments have been used.

AIM

This paper looks at the potential reliability of a sEMG protocol for assessing the intrinsic foot muscles.

METHODS

Six intrinsic muscles were defined using ultrasound and muscle function testing. A protocol for sensor placement was created with repeatability and reliability testing of the protocol conducted by three separate testers on three subjects over two different time frames. Inter tester and Inter session repeatability and reliability was measured with ICC and percentage standard error of measurement.

RESULTS

Although there was good correlation between Extensor Digitorum Brevis, Dorsal Interossei, Abductor Digiti Minimi and Flexor Digitorum Brevis there was increased variability and poor correlation for Flexor hallucis Brevis and Abductor Hallucis. The percentage standard error of measurement did not support the high ICC values indicating a lower precision of measurement.

SIGNIFICANCE

Variability between testers and sessions shows an inconsistent reliability of sEMG and further work is required with protocols focussing on grouping muscles to improve the understanding of the intrinsic foot muscles.

Relationship between skin temperature and soft tissue hardness in diabetic patients: an exploratory study

OBJECTIVE

The role of skin temperature and soft tissue hardness in the development of plantar ulcers is still in debate. However, the relationship between skin temperature and soft tissue hardness has not been explored. This study intends to analyse an eventual association between skin temperature and soft tissue hardness in the foot of diabetic patients Approach: Twenty diabetic patients enrolled for this study. The analysis was done at the foot level, therefore, skin temperature and soft tissue hardness data of the plantar surface of 40 feet were obtained in eight regions of the foot, two in the heel, two in the midfoot, three in the forefoot and one in the hallux. Information regarding glycaemic control (HbA1c levels) was retrieved from the clinical records of the patients.

MAIN RESULTS

After averaging skin temperature and soft tissue hardness in the calcaneum (medial and lateral), in the midfoot (medial and lateral) and in the metatarsal head (1st, 2nd-3rd and 4th-5th), a negative, moderate and significant association was found between skin temperature and soft tissue hardness in the metatarsal head (rho  =  -0.553; p   <  0.001), a positive, low and significant association was found in the midfoot (rho  =  0.333; p   =  0.036), but no association was found in the heel. The multiple linear regression models with skin temperature as dependent variable and soft tissue hardness as predictor were statistically significant in the metatarsal heads and midfoot, and explained 28.8% (R ²  =  0.288, F _(1,38)  =  15.37, p   <  0.001) and 11.9% (R ²  =  0.119, F _(1,38)  =  5.151, p   =  0.029) of the variance in skin temperature, respectively.

SIGNIFICANCE

Skin temperature is negatively associated with soft tissue hardness in the metatarsal head region and positively associated with soft tissue hardness in the midfoot. These findings imply that soft tissue hardness should be considered in the assessment of diabetic foot patients and that this variable should be controlled in studies assessing the determinants of foot skin temperature.

Influence of Diabetes Mellitus on the Recovery Trajectories of Function, Strength, and Self-Report Measures After Total Knee Arthroplasty

OBJECTIVE

As the proportion of individuals with diabetes mellitus (DM) in the aging population and the number of total knee arthroplasties (TKAs) both continue to grow, understanding the outcomes for these patient populations is critical. The purpose of this study was to determine whether patients with and without DM differed in the recovery of 3 physical performance measures during the first 90 days following a TKA.

METHODS

Data collected at ATI Physical Therapy from 169 patients (37 with DM, and 132 without) were available. Physical performance measures included the 4-meter walk test, the 30-second sit-to-stand test (30STS), and the timed-up-and-go test (TUG). A mixed-effects model was performed to determine differences in the rate of recovery and 90-day postoperative scores for all measures.

RESULTS

Both groups had similar baseline values for all measures. Patients with DM demonstrated a slower rate of recovery for the 4-meter walk test, and worse scores for the 4-meter walk test, 30STS, and TUG at the end of 90 days when accounting for significant covariates.

CONCLUSION

Our findings show a negative relationship between the presence of DM and the recovery trajectories of all physical performance measures. Clinicians should closely monitor patients with DM, knowing that they are at higher risk for sustained functional deficits and early complications.

Foot function and strength of patients with diabetes grouped by ulcer risk classification (IWGDF)

BACKGROUND

The stratification system from the International Working Group on the Diabetic Foot (IWGDF) was used to classify the participants as to the ulcer risk. However, it is not yet known what the classification groups' individual deficits are regarding sensitivity, function, and musculoskeletal properties and mechanics. This makes it difficult to design proper ulcer prevention strategies for patients. Thus, this study aimed to investigate the foot function, foot strength and health of people with diabetes mellitus (DM)-with or without DPN-while considering the different ulcer risk classifications determined by the IWGDF.

METHODS

The subject pool comprised 72 people with DM, with and without DPN. The patients were divided into three groups: Group 0 (G0), which comprised diabetic patients without DPN; Group 1 (G1), which comprised patients with DPN; and Group 2 (G2), which comprised patients with DPN who had foot deformities. The health and foot function of the subjects' feet were assessed using a foot health status questionnaire (FHSQ-BR) that investigated four domains: foot pain, foot function, footwear, and general foot health. The patients' foot strength was evaluated using the maximum force under each subject's hallux and toes on a pressure platform (emed q-100, Novel, Munich, Germany).

RESULTS

Moderate differences were found between G0 and G1 and G2 for the foot pain, foot function, general foot health, and footwear. There was also a small but significant difference between G0 and G2 in regards to hallux strength.

CONCLUSION

Foot health, foot function and strength levels of people with DM and DPN classified by the ulcer risk are different and this must be taken into account when evaluating and developing treatment strategies for these patients.

Type 1 diabetes, sport practiced, and ankle joint mobility in young patients: What is the relationship?

BACKGROUND/OBJECTIVE

It is known that patients with diabetes can develop limited joint mobility (LJM) and that this can depend on the metabolic control maintained and the duration of the disease. The aims of this study were to verify the presence of ankle joint mobility (AJM) deficits in both plantar and dorsiflexion in young type 1 diabetic patients (T1D) considering also the possible role of sport practiced as a further factor, able to modify AJM.

METHODS

AJM was evaluated by an inclinometer in 82 T1D patients (M/F: 48/34), mean age 12.9 ± 2.6 years, body mass index (BMI) 19.7 ± 3.6 kg/m² , duration of diabetes 5.6 ± 3.3 years, mean HbA1c 7.5 ± 1.0% and in 226 healthy controls (M/F: 146/80), age-, gender-, and BMI-matched practicing different sports (soccer, volleyball, basketball, and dance).

RESULTS

The patients' ankle range of motion was significantly lower than that in controls (132.7 ± 22.3° vs 126.1 ± 17.9°; P < .017). In particular, ankle plantar flexion was significantly lower in the patients group (31.6° ± 7.9° vs 28.5° ± 6.6°; P < .002). Soccer players showed lower AJM in both groups: patients (120.1 ± 15.9° vs 127.3 ± 18.1) and controls (119.4 ± 21.1° vs 142.0 ± 18.1; P < .0001) than subjects practicing other sports or who were sedentary. In both groups, patients and controls, age, sex, duration of disease, hemoglobin 1Ac, and BMI have not been shown to be correlated to the mobility assessed.

CONCLUSIONS

The results of this study, in addition to confirming the negative effect of diabetes on AJM of young T1D patients, suggest that during these evaluations the sport-related effect should be considered because it can induce significant changes of AJM.

Surgical offloading procedures for diabetic foot ulcers compared to best non-surgical treatment: a study protocol for a randomized controlled trial

Background

Diabetic foot ulcers are frequently related to elevated pressure under a bony prominence. Conservative treatment includes offloading with orthopaedic shoes and custom made orthotics or plaster casts. While casting in plaster is usually effective in achieving primary closure of foot ulcers, recurrence rates are high. Minimally invasive surgical offloading that includes correction of foot deformities has good short and long term results. The surgery alleviates the pressure under the bony prominence, thus enabling prompt ulcer healing, negating the patient's dependence on expensive shoes and orthotics, with a lower chance of recurrence. The purpose of this protocol is to compare offloading surgery (percutaneous flexor tenotomy, mini-invasive floating metatarsal osteotomy or Keller arthroplasty) to non-surgical treatment for patients with diabetic foot ulcers in a semi-crossover designed RCT.

Methods

One hundred patients with diabetic neuropathy related foot ulcers (tip of toe ulcers, ulcers under metatarsal heads and ulcers under the hallux interphalangeal joint) will be randomized (2:3) to a surgical offloading procedure or best available non-surgical treatment. Group 1 (surgery) will have surgery within 1 week. Group 2 (controls) will be prescribed an offloading cast applied for up to 12 weeks (based on clinical considerations). Following successful offloading treatment (ulcer closure with complete epithelization) patients will be prescribed orthopaedic shoes and custom made orthotics. If offloading by cast for at least 6 weeks fails, or the ulcer recurs, patients will be offered surgical offloading. Follow-up will take place till 2 years following randomization. Outcome criteria will be time to healing of the primary ulcer (complete epithelization), time to healing of surgical wound, recurrence of ulcer, time to recurrence and complications.

Discussion

The high recurrence rate of foot ulcers and their dire consequences justify attempts to find better solutions than the non-surgical options available at present. To promote surgery, RCT level evidence of efficacy is necessary.

Trial registration

Israel MOH_2017-08-10_000719. NIH: NCT03414216.

History, Prevalence and Assessment of Limited Joint Mobility, from Stiff Hand Syndrome to Diabetic Foot Ulcer Prevention: A Narrative Review of the Literature

BACKGROUND

Limited Joint Mobility (LJM) is a dreaded complication of Diabetes Mellitus (DM). During the last half century, LJM has been studied in patients of different age because it has been considered useful for the monitoring of a patient's condition and for the prevention of vascular disease and diabetic foot.

OBJECTIVES

The main aims of this review are to describe the relationship between DM and joint mobility as well as its prevalence and assessment. We have also investigated the role of LJM in the development of diabetic foot ulcers.

METHODOLOGY

An in-depth literature search was conducted to identify studies that examined the prevalence and characteristics of LJM in patients with DM of different types, age, durations and chronic complications.

RESULTS

Many factors (therapy improvements, population characteristics and different evaluation methods) concur to hinder an exact assessment of the prevalence of LJM. However, it has been confirmed that LJM is widespread among patients with DM and may affect more than two-thirds of them in addition to being a major risk factor for foot ulcer. Its role in the monitoring of a patient's condition is also important for the definition of risk thresholds such as in patients with diabetic foot. The efficacy of exercise therapy for the treatment of LJM, also in patients at risk of foot ulcer, has not been discussed.

CONCLUSION

Difficulties encountered in the definition of the prevalence of LJM may hinder its study and the establishment of preventive interventions. However, LJM plays a key role in the monitoring of patients, especially those at risk for ulcer.

Physical Training and Activity in People With Diabetic Peripheral Neuropathy: Paradigm Shift

Diabetic peripheral neuropathy (DPN) occurs in more than 50% of people with diabetes and is an important risk factor for skin breakdown, amputation, and reduced physical mobility (ie, walking and stair climbing). Although many beneficial effects of exercise for people with diabetes have been well established, few studies have examined whether exercise provides comparable benefits to people with DPN. Until recently, DPN was considered to be a contraindication for walking or any weight-bearing exercise because of concerns about injuring a person's insensitive feet. These guidelines were recently adjusted, however, after research demonstrated that weight-bearing activities do not increase the risk of foot ulcers in people who have DPN but do not have severe foot deformity. Emerging research has revealed positive adaptations in response to overload stress in these people, including evidence for peripheral neuroplasticity in animal models and early clinical trials. This perspective article reviews the evidence for peripheral neuroplasticity in animal models and early clinical trials, as well as adaptations of the integumentary system and the musculoskeletal system in response to overload stress. These positive adaptations are proposed to promote improved function in people with DPN and to foster the paradigm shift to including weight-bearing exercise for people with DPN. This perspective article also provides specific assessment and treatment recommendations for this important, high-risk group.

Metatarsophalangeal Hyperextension Movement Pattern Related to Diabetic Forefoot Deformity

BACKGROUND

Metatarsophalangeal joint (MTPJ) hyperextension deformity is common in people with diabetic neuropathy and a known risk factor for ulceration and amputation. An MTPJ hyperextension movement pattern may contribute to the development of this acquired deformity.

OBJECTIVE

The purpose of this study was to determine, in people with diabetes mellitus and peripheral neuropathy (DM+PN), the ankle and MTPJ ranges of motion that characterize an MTPJ hyperextension movement pattern and its relationship to MTPJ deformity severity. It was hypothesized that severity of MTPJ deformity would be related to limitations in maximum ankle dorsiflexion and increased MTPJ extension during active ankle dorsiflexion movement tasks.

DESIGN

A cross-sectional study design was used that included 34 people with DM+PN (mean age=59 years, SD=9).

METHODS

Computed tomography and 3-dimensional motion capture analysis were used to measure resting MTPJ angle and intersegmental foot motion during the tasks of ankle dorsiflexion and plantar flexion with the knee extended and flexed to 90 degrees, walking, and sit-to/from-stand.

RESULTS

The MTPJ extension movement pattern during all tasks was directly correlated with severity of MTPJ deformity: maximum ankle dorsiflexion with knee extended (r=.35; 95% confidence interval [CI]=.02, .62), with knee flexed (r=.35; 95% CI=0.01, 0.61), during the swing phase of gait (r=.47; 95% CI=0.16, 0.70), during standing up (r=.48; 95% CI=0.17, 0.71), and during sitting down (r=.38; 95% CI=0.05, 0.64). All correlations were statistically significant.

LIMITATIONS

This study was cross-sectional, and causal relationships cannot be made.

CONCLUSIONS

A hyperextension MTPJ movement pattern associated with limited ankle dorsiflexion has been characterized in people with diabetic neuropathy. Increased MTPJ extension during movement and functional tasks was correlated with severity of resting MTPJ alignment. Repetition of this movement pattern could be an important factor in the etiology of MTPJ deformity and future risk of ulceration.