Abnormal foot function in diabetic patients: the altered onset of Windlass mechanism

Ultrasound Evaluation of Achilles Tendon Thickness in Diabetic Patients With and Without Foot Complications

Introduction Diabetes mellitus (DM) is a multifaceted metabolic disorder distinguished by elevated blood sugar levels. Type 2-DM (T2DM) stands as a significant contributor to disability due to its widespread occurrence of microvascular and macrovascular complications. According to certain researchers, prolonged elevated blood sugar levels have been observed to trigger a sequence of irregular alterations in the Achilles tendon (AT). AT thickness is one such indicator of these alterations. Methods This was a prospective study carried out on 51 individuals which was further divided into 3 groups (Group A - Normal individuals, Group B - DM without foot complications, Group C - DM with foot complications) with 17 individuals in each as healthy, DM with foot complications and without complications at Sri Devaraj Urs Medical College over a period of one year. The patients' demographics, basic medical records, and laboratory test results were examined and analyzed. Results The mean age of the study participants was 55.41 + 10.25 years. There was no significant difference in age and gender between the three groups. There was a significant difference in mean AT thickness between the groups (p<0.05). The mean thickness of AT was higher in Group C compared to Group B. Group A had the least AT thickness. However, there was no correlation between the variables in individual groups. Conclusions Modifications in the AT's structure may occur before the onset of foot and ankle issues in individuals with diabetes. Hence, the thickening of the AT can be used as an early indicator of impending diabetic foot complications.

Do the fasciae of the soleus have a role in plantar fasciitis?

Plantar fasciitis is a chronic, self-limiting, and painful disabling condition affecting the inferomedial aspect of the heel, usually extending toward the metatarsophalangeal joints. There is compelling evidence for a strong correlation between Achilles tendon (AT) loading and plantar aponeurosis (PA) tension. In line with this, tightness of the AT is found in almost 80% of patients affected by plantar fasciitis. A positive correlation has also been reported between gastrocnemius-soleus tightness and heel pain severity in this condition. Despite its high prevalence, the exact etiology and pathological mechanisms underlying plantar heel pain remain unclear. Therefore, the aim of the present paper is to discuss the anatomical and biomechanical substrates of plantar fasciitis with special emphasis on the emerging, though largely neglected, fascial system. In particular, the relationship between the fascia, triceps surae muscle, AT, and PA will be analyzed. We then proceed to discuss how structural and biomechanical alterations of the muscle-tendon-fascia complex due to muscle overuse or injury can create the conditions for the onset of PA pathology. A deeper knowledge of the possible molecular mechanisms underpinning changes in the mechanical properties of the fascial system in response to altered loading and/or muscle contraction could help healthcare professionals and clinicians refine nonoperative treatment strategies and rehabilitation protocols for plantar fasciitis.

Plantar fascia stiffness in patients with type 2 diabetes mellitus: Stiffness effect on fall risk and gait speed

AIMS

The primary objective was to compare patients with type 2 diabetes mellitus (T2DM) and healthy peers in terms of plantar fascia (PF) stiffness, fall risk, and gait speed. The second objective was to examine the relationship between stiffness of PF and fall risk, gait speed.

METHODS

Fifty patients diagnosed with T2DM (mean duration = 10.74 ± 7.07 years) were included. Myotonometer was used to evaluate the stiffness of PF. To assess the risk of falling, and gait speed, the International Fall Efficiency Scale (FES-I) and the 4-Meter Gait Speed Test (4mGST) were used, respectively.

RESULTS

Compared to healthy controls, PF stiffness (right foot mean difference = 148.99 N/m, left foot mean difference = 113.13 N/m p < .001) was higher in the T2DM group. The FES-I and 4mGST scores were worse in the group with T2DM (p < .05). 12.8 % of FES-I and 23.4 % of 4mGST variance were explained by stiffness of PF.

CONCLUSIONS

The results of the study showed that the stiffness of PF changed in patients with T2DM. There was a decrease in gait speed and an increase in the risk of falling as PF stiffness increased.

Compromised neuromuscular function of walking in people with diabetes: a narrative review

AIM

This review summarizes recent studies that have investigated the neuromuscular dysfunction of walking in people with diabetes and its relationship to ulcer formation.

METHODS

A comprehensive electronic search in the database (Scopus, Web of Science, PsycINFO, ProQuest, and PubMed) was performed for articles pertaining to diabetes and gait biomechanics.

RESULTS

The Achilles tendon is thicker and stiffer in those with diabetes. People with diabetes demonstrate changes in walking kinematics and kinetics, including slower self-selected gait speed, shorter stride length, longer stance phase duration, and decreased ankle, knee, and metatarsophalangeal (MTP) joint range of motion. EMG is altered during walking and may reflect diabetes-induced changes in muscle synergies. Synergies are notable because they provide a more holistic pattern of muscle activations and can help develop better tools for characterizing disease progression.

CONCLUSION

Diabetes compromises neuromuscular coordination and function. The mechanisms contributing to ulcer formation are incompletely understood. Diabetes-related gait impairments may be a significant independent risk factor for the development of foot ulcers.

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.

Diabetes mellitus tendino-myopathy: epidemiology, clinical features, diagnosis and management of an overlooked diabetic complication

Tendino-myopathy, an unexplored niche, is a non-vascular unstated T2DM complication, which is largely disregarded in clinical practice, thus, we aim to explore it in this review. Literature search using published data from different online resources. Epidemiologically, reported prevalence varies around 10-90%, which is marked variable and unreliable. Clinically, diabetic tendino-myopathy is typified by restriction of movement, pain/tenderness, cramps and decreased functions. Moreover, myopathy is characterized by muscle atrophy, weakness and ischemia, and tendinopathy by deformities and reduced functions/precision. In tendonapthy, the three most affected regions are: the hand (cheiroarthropathy, Dupuytren's contracture, flexor tenosynovitis and carpel tunnel syndrome), shoulder (adhesive capsulitis, rotator cuff tendinopathy and tenosynovitis) and foot (Achilles tendinopathy with the risk of tear/rupture), in addition to diffuse idiopathic skeletal hyperostosis. Pathologically, it is characterized by decreased muscle fiber mass and increased fibrosis, with marked extracellular matrix remodeling and deposition of collagens. The tendon changes include decreased collagen fibril diameter, changed morphology, increased packing and disorganization, with overall thickening, and calcification. Diagnosis is basically clinical and radiological, while diagnostic biomarkers are awaited. Management is done by diabetes control, special nutrition and physiotherapy, while analgesics, steroids and surgery are used in tendinopathy. Several antisarcopenic drugs are in the pipeline. This review aims to bridge clinical practice with research and update routine diabetic checkup by inclusion of tendino-myopathies in the list with an emphasis on management.

Human Achilles tendon mechanical behavior is more strongly related to collagen disorganization than advanced glycation end-products content

Diabetes is associated with impaired tendon homeostasis and subsequent tendon dysfunction, but the mechanisms underlying these associations is unclear. Advanced glycation end-products (AGEs) accumulate with diabetes and have been suggested to alter tendon function. In vivo imaging in humans has suggested collagen disorganization is more frequent in individuals with diabetes, which could also impair tendon mechanical function. The purpose of this study was to examine relationships between tendon tensile mechanics in human Achilles tendon with accumulation of advanced glycation end-products and collagen disorganization. Achilles tendon specimens (n = 16) were collected from individuals undergoing lower extremity amputation or from autopsy. Tendons were tensile tested with simultaneous quantitative polarized light imaging to assess collagen organization, after which AGEs content was assessed using a fluorescence assay. Moderate to strong relationships were observed between measures of collagen organization and tendon tensile mechanics (range of correlation coefficients: 0.570-0.727), whereas no statistically significant relationships were observed between AGEs content and mechanical parameters (range of correlation coefficients: 0.020-0.210). Results suggest that the relationship between AGEs content and tendon tensile mechanics may be masked by multifactorial collagen disorganization at larger length scales (i.e., the fascicle level).

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.

Plantar soft tissues and Achilles tendon thickness and stiffness in people with diabetes: a systematic review

BACKGROUND

Diabetes mellitus is associated with changes in soft tissue structure and function. However, the directionality of this change and the extent to which either tissue thickness or stiffness contributes to the pathogenesis of diabetes-related foot ulcerations is unclear. Hence, this systematic review aims to summarise the existing evidence for soft tissue structural differences in the feet of people with and without diabetes.

METHODS

In compliance with MOOSE and PRISMA guidelines, AMED, CINAHL, MEDLINE, ProQuest Health & Medical Collection, ProQuest Nursing & Allied Health Database, and Web of Science electronic databases were systematically searched for studies published from database inception until 1st October 2020 [Prospero CRD42020166614]. Reference lists of included studies were further screened. Methodological quality was appraised using a modified critical appraisal tool for quantitative studies developed by McMaster University.

RESULTS

A total of 35 non-randomised observational studies were suitable for inclusion. Within these, 20 studies evaluated plantar tissue thickness, 19 studies evaluated plantar tissue stiffness, 9 studies evaluated Achilles tendon thickness and 5 studies evaluated Achilles tendon stiffness outcomes. No significant differences in plantar tissue thickness were found between people with and without diabetes in 55% of studies (11/20), while significantly increased plantar tissue stiffness was found in people with diabetes in 47% of studies (9/19). Significantly increased Achilles tendon thickness was found in people with diabetes in 44% of studies (4/9), while no significant differences in Achilles tendon stiffness were found between people with and without diabetes in 60% of studies (3/5).

CONCLUSIONS

This systematic review found some evidence of soft tissue structural differences between people with and without diabetes. However, uncertainty remains whether these differences independently contribute to diabetes-related foot ulcerations. The heterogeneity of methodological approaches made it difficult to compare across studies and methodological quality was generally inadequate. High-quality studies using standardised and validated assessment techniques in well-defined populations are required to determine more fully the role of structural tissue properties in the pathogenesis of diabetes-related foot ulcerations.

Reliability in ultrasound measurements of plantar aponeurosis thickness

PURPOSE

Given the increasing research interest in ultrasound plantar aponeurosis (PA) thickness measurements, this study aimed to analyze the inter and intra-rater reliability of independent sonograms and to identify the error related to the image analysis procedure.

METHODS

Twenty-one healthy men participated in this study. Imaging of PA consisted of two independent sonograms per subject. Two raters (R1 and R2) evaluated each sonogram twice using standardized steps. Precision of the image analysis procedure was analyzed using the Bland and Altman plot and Intraclass Correlation Coefficient (ICC). Agreement estimates and ICC were used to assess absolute and relative inter and intra-rater reliability.

RESULTS

Reliability of PA thickness was found to depend strongly on the number of images acquired per subject. Intra-rater agreement for single measurements were 0.696 (R1) and 0.495 (R2), whereas average measurements yielded values of 0.821 (R1) and 0.662 (R2), respectively. Precision within a sonogram varied from ICC values of 0.873 to 0.960 (intra-rater) and 0.670 to 0.822 (inter-rater).

CONCLUSION

Most part of the error in PA thickness measurements seems to be related to the sonogram acquisition process and not to the visual inspection of the image. To minimize error, average values of a minimum of two images per subject should be used. The moderate agreement between raters found in this study ratifies the need of all measurements being made by the same rater or group of raters. If a single rater evaluates all subjects, performing multiple measurements over one image does not seem to affect ICC as much as acquiring multiple images.

Diabetic Pilon Factures: Are They as Bad as We Think?

OBJECTIVE

To identify how diabetes impacts the risk of complications requiring further surgery (deep surgical site infection, nonunion, amputation, and arthrodesis) after pilon fracture fixation.

DESIGN

Retrospective cohort study.

SETTING

Level 1 academic trauma center.

PATIENTS

Two hundred seventy-nine pilon fractures (276 patients) were identified. A retrospective review was performed to find patients who presented for open reduction and internal fixation of a tibial pilon fracture (OTA/AO 43). Patient demographics, medical comorbidities, OTA/AO fracture type, and surgical outcomes were reviewed.

INTERVENTION

Patients were stratified into cohorts based on the presence or absence of diabetes at the time of surgery.

MAIN OUTCOME MEASUREMENTS

The complications of interest that proved significant during univariate analyses were then entered into a multivariable logistic regression model using a stepwise method to identify the independent predictors for complications.

RESULTS

There were 43 fractures (15.4%) in patients with diabetes mellitus; 17 (39.5%) of whom were insulin-dependent diabetics. Diabetic patients were significantly more likely to have a higher body mass index (34.81 vs. 29.57, P = 0.002) and be older (55.30 ± 16.3 years vs. 41.70 ± 14.05, P < 0.001) at the time of injury. Patients without diabetes were more likely to sustain an OTA/AO 43-C3 fracture (36.0% vs. 11.6%, P = 0.001). Diabetic patients were 5.5 times more likely to require an arthrodesis [95% confidence interval (CI) = 1.894-16.214; P = 0.001] and 2.7 times more likely to develop a deep infection (95% CI = 1.261-5.630; P = 0.008).

CONCLUSIONS

Overall, diabetic patients in this study were 3.64 times more likely (95% CI = 1.854-7.159; P < 0.001) to experience any complication, despite having less complex fractures.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Achilles tendon degeneration on ultrasound in type 2 diabetic patients

Aim of study

The main goal of this study was to compare the various degenerative changes in the Achilles tendon of type 2 diabetic patients to that of controls. The influence of diabetic peripheral neuropathy, duration of diabetes mellitus, age, and body mass index on the occurrence of degenerative changes was also evaluated.

Materials and methods

The Achilles tendons of both limbs were evaluated with high-resolution ultrasound in 80 type 2 diabetics and 80 age/sex-matched controls. A 10 g Semmes Weinstein monofilament was used to examine for peripheral neuropathy. Anthropometric measurements and biochemical assessment of glycemic control (fasting plasma glucose and glycated hemoglobin) were also done.

Results

The mean age of type 2 diabetic subjects and healthy controls was 60.9 ± 10.3 years (range 41–79 years) and 61.0 ± 10.3 years (range 40–79 years), respectively (p = 0.963). The median duration of diabetes mellitus was 42.0 months (range = 1–456 months). The prevalence of degenerative changes (calcifications, disorganized fibers and/or hypoechoic foci) was significantly higher in type 2 diabetic subjects than controls in both the right (55.0% vs. 18.8%, p <0.001) and left (52.5% vs. 18.8%, p <0.001) feet.

Conclusion

The Achilles tendons of type 2 diabetic subjects have significantly more degenerative changes than their age/sex-matched controls in our locality. Disorganized Achilles tendon fibers occur significantly more often among male than female type 2 diabetic subjects. Disorganization of Achilles tendon fibers and hypoechoic foci are significantly more prevalent in type 2 diabetic subjects with peripheral neuropathy than those without peripheral neuropathy. Body mass index did not affect the occurrence of degenerative changes in the Achilles tendon of participants.

Effects of Type II Diabetes Mellitus on Tendon Homeostasis and Healing

Over 300,000 tendon repairs are performed annually in the United States to repair damage to tendons as a result of either acute trauma or chronic tendinopathy. Individuals with type II diabetes mellitus (T2DM) are four times more likely to experience tendinopathy, and up to five times more likely to experience a tendon tear or rupture than non-diabetics. As nearly 10% of the US population is diabetic, with an additional 33% pre-diabetic, this is a particularly problematic health care challenge. Tendon healing in general is challenging and often unsatisfactory due to the formation of mechanically inferior scar-tissue rather than regeneration of native tendon structure. In T2DM tendons, there is evidence of an amplified scar tissue response, which may be associated with the increased the risk of rupture or impaired restoration of range of motion. Despite the dramatic effect of T2DM on tendon function and outcomes following injury, there are few therapies available to promote improved healing in these patients. Several recent studies have enhanced our understanding of the pro-inflammatory environment of T2DM healing and have assessed potential treatment approaches to mitigate pathological progression in pre-clinical models of diabetic tendinopathy. This review discusses the current state of knowledge of diabetic tendon healing from molecular to mechanical disruptions and identifies promising approaches and critical knowledge gaps as the field moves toward identification of novel therapeutic strategies to maintain or restore tendon function in diabetic patients. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:13-22, 2020.

Healing ulcers and preventing their recurrences in the diabetic foot

Fifteen percent of people with diabetes develop an ulcer in the course of their lifetime. Eighty-five percent of the major amputations in diabetes mellitus are preceded by an ulcer. Management of ulcers and preventing their recurrence is important for the quality of life of the individual and reducing the cost of care of treatment. The main causative factors of ulceration are neuropathy, vasculopathy and limited joint mobility. Altered bio-mechanics due to the deformities secondary to neuropathy and limited joint mobility leads to focal points of increased pressure, which compromises circulation leading to ulcers. Ulcer management must not only address the healing of ulcers but also should correct the altered bio-mechanics to reduce the focal pressure points and prevent recurrence. An analysis of 700 patients presenting with foot problems to the Diabetic Clinic of Ganga Hospital led to the stratification of these patients into four classes of incremental severity. Class 1 – the foot at risk, Class 2 – superficial ulcers without infection, Class 3 – the crippled foot and Class 4 – the critical foot. Almost 77.5% presented in either Class 3 or 4 with complicated foot ulcers requiring major reconstruction or amputation. Class 1 foot can be managed conservatively with foot care and appropriate foot wear. Class 2 in addition to measures for ulcer healing would need surgery to correct the altered bio-mechanics to prevent the recurrence. The procedures called surgical offloading would depend on the site of the ulcer and would need an in-depth clinical study of the foot. Class 3 would need major reconstructive procedures and Class 4 would need amputation since it may be life-threatening. As clinicians, our main efforts must be focused towards identifying patients in Class 1 and offer advice on foot care and Class 2 where appropriate surgical offloading procedure would help preserve the foot.

Acoustic Radiation Force Impulse Elastography and Ultrasonographic Findings of Achilles Tendon in Patients With and Without Diabetic Peripheral Neuropathy: A Cross-Sectional Study

AIMS

We aimed to evaluate the elastographic features of Achilles tendon with Acoustic Radiation Force Impulse in patients with and without diabetic neuropathy.

METHODS

According to the presence of peripheral neuropathy, 45 patients with type 2 diabetes were divided into 2 subgroups. Those with peripheral neuropathy were defined as group I (22 patients) and those without peripheral neuropathy were defined as group II (23 patients). A total of thirty age-, gender-, and body mass index-matched healthy individuals were selected as controls. All participants underwent both ultrasonographic and Acoustic Radiation Force Impulse elastographic examination in order to evaluate Achilles Tendon thickness and stiffness.

RESULTS

Achilles tendon thicknesses were similar between groups (p=0.991). Achilles tendon thicknesses of both patient groups were significantly higher than the control group (group I vs control p=0.01; group II vs control p=0.006). Stiffness values of Achilles tendons were similar between the control group and group II (p=0.993). Shear Wave Velocity was significantly lower in group I than group IIand control group (p<0.001).

CONCLUSION

Diabetic patients with neuropathy have thicker and softer Achilles tendon while the elasticity of Achilles tendon in diabetic patients without neuropathy is similar to the healthy controls. Softening of the Achilles tendon may be an early sign of diabetic foot and reveal the patients with a risk of diabetic foot.

Diabetic Gait Is Not Just Slow Gait: Gait Compensations in Diabetic Neuropathy

BACKGROUND

Neuropathic complications from diabetes mellitus affect multiple nerve types and may manifest in gait. However, gait compensations are still poorly understood, as narrow analyses and lack of speed controls have contributed to conflicting or equivocal results.

PURPOSE

To evaluate gait mechanics and energetics in diabetic peripheral polyneuropathy.

METHODS

Instrumented gait analysis was performed on 14 participants with diabetic peripheral polyneuropathy and 14 matched controls, walking at 1.0 m/s. A full-body model with a multisegment foot was used to calculate inverse dynamics and analyze sagittal plane metrics and time series waveforms across stance phase.

RESULTS

Alterations included increased hip and knee flexion in early stance followed by a prolonged hip extension moment in midstance. Late stance ankle dorsiflexion and power absorption were increased, and final push-off was delayed and truncated.

CONCLUSION

A neuropathic diabetic gait shares important similarities to a mild crouch gait with weakness/dysfunction in the foot and ankle. This study highlights two main compensation mechanisms that have been overlooked in previous literature. First, increased triceps surae stretch in terminal stance may be used to increase proprioception and/or energy storage, while a prolonged hip extension moment in midstance compensates for a limited push-off. These result in an overall workload shift from distal to proximal joints. Clinical assessment, monitoring, and treatment of neuropathy may benefit by focusing on these specific functional alterations.

Quadriceps muscle architecture ultrasonography of individuals with type 2 diabetes: Reliability and applicability

Muscle architecture parameters performed using ultrasound serve as an aid to monitor muscle changes derived from diseases, however there are no studies that determine the reliability and applicability of this evaluation in individuals with type 2 diabetes (DM2). Three raters captured three images of measurements of thickness of the rectus femoris (RF), vastus intermedius and anterior quadriceps, RF muscle cross-sectional area, RF pennation angle in 17 individuals with DM2 above 50 and sedentary. Intra and inter-raters analysis showed reliability from high to very high for the three raters (ICC> 0.87), except for the RF pennation angle with moderate to low intra-raters (ICC = 0.58, 0.48, 0.51), and high inter-rater reliability (ICC = 0.70). Ultrasound measurements of quadriceps muscles showed high to very high intra and inter-raters reliability, thus allowing its use to monitor muscle changes provoked by diabetes or interventions in individuals with DM2.

Duration of Type 2 Diabetes is a Predictor of Elevated Plantar Foot Pressure

AIMS

Elevated plantar pressure is considered a significant risk factor for ulceration in diabetes mellitus. The aim of this study was to determine whether duration of diabetes could affect plantar pressure in patients with no known significant comorbidity or foot pathology.

METHODS

Participants with type 2 diabetes, but without known confounding factors that could alter peak pressure, were matched for age, weight, and gender and categorized into 3 groups of diabetes duration: group 1 (1-5 yr), group 2 (6-10 yr), and group 3 (11-15 yr). Plantar pressures were recorded utilizing a two-step protocol at a self-selected speed.

RESULTS

One-way analysis of variance (ANOVA) revealed significant differences in mean peak plantar pressures between the three groups under the 2^nd - 4^th metatarsophalangeal joint (MPJ) region of interest (ROI) (p = 0.012 and p = 0.022, respectively) and left heel (p = 0.049). Also, a significant difference in mean pressure-time integral under the left 2^nd - 4^th MPJ ROI (p = 0.021) and right heel (p = 0.048) was observed. Regression analysis confirmed that mean peak plantar pressures in the first group (but not in the second group) were significantly lower than in the third group (p = 0.005).

CONCLUSIONS

As the duration of diabetes increased, peak plantar pressure increased significantly under the 2^nd - 4^th MPJ ROIs. These findings suggest that clinicians should make more use of pressure mapping technology as part of their clinical management plan in patients with diabetes >10 yr, even if they have no complications or deformities, to preserve functional limbs in this high-risk population.

Quantifying Dynamic Changes in Plantar Pressure Gradient in Diabetics with Peripheral Neuropathy

Diabetic foot ulcers remain one of the most serious complications of diabetes. Peak plantar pressure (PPP) and peak pressure gradient (PPG) during walking have been shown to be associated with the development of diabetic foot ulcers. To gain further insight into the mechanical etiology of diabetic foot ulcers, examination of the pressure gradient angle (PGA) has been recently proposed. The PGA quantifies directional variation or orientation of the pressure gradient during walking and provides a measure of whether pressure gradient patterns are concentrated or dispersed along the plantar surface. We hypothesized that diabetics at risk of foot ulceration would have smaller PGA in key plantar regions, suggesting less movement of the pressure gradient over time. A total of 27 participants were studied, including 19 diabetics with peripheral neuropathy and 8 non-diabetic control subjects. A foot pressure measurement system was used to measure plantar pressures during walking. PPP, PPG, and PGA were calculated for four foot regions – first toe (T1), first metatarsal head (M1), second metatarsal head (M2), and heel (HL). Consistent with prior studies, PPP and PPG were significantly larger in the diabetic group compared with non-diabetic controls in the T1 and M1 regions, but not M2 or HL. For example, PPP was 165% (P = 0.02) and PPG was 214% (P < 0.001) larger in T1. PGA was found to be significantly smaller in the diabetic group in T1 (46%, P = 0.04), suggesting a more concentrated pressure gradient pattern under the toe. The proposed PGA may improve our understanding of the role of pressure gradient on the risk of diabetic foot ulcers.

Foot deformities within the diabetic foot and their influence on biomechanics: A review of the literature

BACKGROUND

Diabetes mellitus causes a multitude of complications. Foot ulceration is one complication with serious consequences, amputation. Foot deformities contribute to ulcer development. It would be advantageous to ascertain whether foot deformities are preventable as their presence increases amputation risk.

OBJECTIVES

The objectives were to understand the development of foot deformities in diabetes and explore their biomechanical effects.

STUDY DESIGN

Literature review.

METHODS

In February 2014 CINAHL, Embase, Ovid and Medline were searched. Studies in English of adults with Diabetes that reported neuropathy, foot deformities or associated gait abnormalities were included for review. All study designs were considered. The articles' quality was considered high overall, assessed using SIGN and CARS.

RESULTS

In total, 17 studies were reviewed. The main themes identified in relation to foot deformities were nerve function, intrinsic foot muscles, muscle weakness and limited joint mobility. Nerve function and intrinsic foot muscle atrophy did not display definitive associations with foot deformities. However, muscle weakness and limited joint mobility were associated with foot deformities, although the relationship is still unclear.

CONCLUSION

The development of common foot deformities in diabetes is not well understood. The literature did not support the common belief that motor neuropathy, atrophy and muscle imbalance cause foot deformities.

CLINICAL RELEVANCE

An understanding of the aetiology of foot deformities in diabetes mellitus may allow for pro-active management of the foot in anticipation of the development of foot deformities and ulceration. If the aetiology of deformity was established preventative treatment may reduce the incidence of foot deformities and resultant ulcerations and amputations.

Acquired midfoot deformity and function in individuals with diabetes and peripheral neuropathy

BACKGROUND

Diabetes mellitus related medial column foot deformity is a major contributor to ulceration and amputation. However, little is known about the relationship between medial column alignment and function and the integrity of the soft tissues that support and move the medial column. The purposes of this study were to determine the predictors of medial column alignment and function in people with diabetes and peripheral neuropathy.

METHODS

23 participants with diabetes and neuropathy had radiographs, heel rise kinematics, magnetic resonance imaging and isokinetic muscle testing to measure: 1) medial column alignment (Meary's angle--the angle between the 1st metatarsal longitudinal axis and the talar head and neck), 2) medial column function (forefoot relative to hindfoot plantarflexion during heel rise), 3) intrinsic foot muscle and fat volume, ratio of posterior tibialis to flexor digitorum tendon volume, 4) plantar fascia function (Meary's angle change from toes flat to extended) and 5) plantarflexor peak torque. Predictors of medial column alignment and function were determined using simultaneous entry multiple regression.

FINDINGS

Posterior tibialis to flexor digitorum tendon volume ratio and intrinsic foot muscle volume were significant predictors of medial column alignment (P<.05), accounting for 44% of the variance. Intrinsic foot fat volume and plantarflexor peak torque were significant predictors of medial column function (P<.05), accounting for 37% of the variance.

INTERPRETATION

Deterioration of medial column supporting structures predicted alignment and function. Prospective research is required to monitor alignment, structure, and function over time to inform early intervention strategies to prevent deformity, ulceration, and amputation.

Rehabilitation of Tendon Problems in Patients with Diabetes Mellitus

Exercise is crucial in the management of diabetes mellitus and its associated complications. However, individuals with diabetes have a heightened risk of musculoskeletal problems, including tendon pathologies. Diabetes has a significant impact on the function of tendons due to the accumulation of advanced glycation end-products in the load-bearing collagen. In addition, tendon vascularity and healing may be reduced due to diabetes-induced changes in the peripheral vascular system, and impaired synthesis of collagen and glycosaminoglycan. The current chapter presents an evidence-based discussion of considerations for the rehabilitation of tendon problems in people with diabetes. The following conditions are discussed in detail - calcific tendinopathy, tenosynovitis, tendon rupture, and non-calcifying tendinopathy. Common diabetes-related findings are presented, along with their potential impact on tendinopathy management and suggested modifications to standard tendinopathy treatment protocols. A holistic approach should be used to optimize musculotendinous function, including a comprehensive exercise prescription addressing strength, flexibility, and aerobic fitness.

Does type 1 diabetes mellitus affect Achilles tendon response to a 10 km run? A case control study

Background

Achilles tendon structure deteriorates 2-days after maximal loading in elite athletes. The load-response behaviour of tendons may be altered in type 1 diabetes mellitus (T1DM) as hyperglycaemia accelerates collagen cross-linking. This study compared Achilles tendon load-response in participants with T1DM and controls.

Methods

Achilles tendon structure was quantified at day-0, day-2 and day-4 after a 10 km run. Ultrasound tissue characterisation (UTC) measures tendon structural integrity by classifying pixels as echo-type I, II, III or IV. Echo-type I has the most aligned collagen fibrils and IV has the least.

Results

Participants were 7 individuals with T1DM and 10 controls. All regularly ran distances greater than 5 km and VISA-A scores indicated good tendon function (T1DM = 94 ± 11, control = 94 ± 10). There were no diabetic complications and HbA1c was 8.7 ± 2.6 mmol/mol for T1DM and 5.3 ± 0.4 mmol/mol for control groups. Baseline tendon structure was similar in T1DM and control groups – UTC echo-types (I-IV) and anterior-posterior thickness were all p > 0.05. No response to load was seen in either T1DM or control group over the 4-days post exercise.

Conclusion

Active individuals with T1DM do not have a heightened Achilles tendon response to load, which suggests no increased risk of tendon injury. We cannot extrapolate these findings to sedentary individuals with T1DM.

Real-time sonoelastography and ultrasound evaluation of the Achilles tendon in patients with diabetes with or without foot ulcers: a cross sectional study

BACKGROUND

Diabetes mellitus (DM) is an endocrine disease characterized by metabolic abnormalities and long-term complications. The Achilles tendon (AT) plays an important role in foot biomechanics. We aimed to investigate the effect of DM on the Achilles tendon, which may contribute to long-term complications in the foot-ankle complex.

METHODS

Seventy-eight patients with diabetes, with (35 patients, group I) or without (43 patients, group II) foot ulcers were recruited from the endocrinology clinic. Thirty-three age-, gender-, and BMI-matched healthy individuals were selected as controls. All participants underwent ultrasonography and sonoelastography of their AT in order to evaluate Achilles tendon thickness (ATT) and stiffness (ATS). Each patient was also tested for fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA1C) as a measure of diabetes control. Other chronic complications were also evaluated in all patients with diabetes.

RESULTS

The AT was significantly thicker in group I compared to group II and the controls. HbA1C, FPG, and duration of diabetes were higher in group I. We observed that ATT was positively correlated with neuropathy, retinopathy, nephropathy, peripheral arterial disease and coronary arterial disease in group II while this correlation was not detected in group I. ATS was reduced in group I more than group II and control groups.

CONCLUSION

Changes in the structure of the AT may precede foot ankle disorders in patients with diabetes. This is the first study that reported the results of sonoelastosonography of AT in patients with diabetes and revealed the correlation between ATT and other chronic complications of diabetes.

Lower limb complications of diabetes mellitus: a comprehensive review with clinicopathological insights from a dedicated high-risk diabetic foot multidisciplinary team

Diabetic complications in the lower extremity are associated with significant morbidity and mortality, and impact heavily upon the public health system. Early and accurate recognition of these abnormalities is crucial, enabling the early initiation of treatments and thus avoiding or minimizing deformity, dysfunction and amputation. Following careful clinical assessment, radiological imaging is central to the diagnostic and follow-up process. We aim to provide a comprehensive review of diabetic lower limb complications designed to assist radiologists and to contribute to better outcomes for these patients.

Balance and ankle muscle strength predict spatiotemporal gait parameters in individuals with diabetic peripheral neuropathy

AIMS

The aims of this study were to evaluate aspects of balance, ankle muscle strength and spatiotemporal gait parameters in individuals with diabetic peripheral neuropathy (DPN) and verify whether deficits in spatiotemporal gait parameters were associated with ankle muscle strength and balance performance.

MATERIALS AND METHODS

Thirty individuals with DPN and 30 control individuals have participated. Spatiotemporal gait parameters were evaluated by measuring the time to walk a set distance during self-selected and maximal walking speeds. Functional mobility and balance performance were assessed using the Functional Reach and the Time Up and Go tests. Ankle isometric muscle strength was assessed with a handheld digital dynamometer. Analyses of variance were employed to verify possible differences between groups and conditions. Multiple linear regression analysis was employed to uncover possible predictors of gait deficits.

RESULTS

Gait spatiotemporal, functional mobility, balance performance and ankle muscle strength were affected in individuals with DPN. The Time Up and Go test performance and ankle muscle isometric strength were associated to spatiotemporal gait changes, especially during maximal walking speed condition.

CONCLUSION

Functional mobility and balance performance are damaged in DPN and balance performance and ankle muscle strength can be used to predict spatiotemporal gait parameters in individuals with DPN.

Biomechanical properties and histology of db/db diabetic mouse Achilles tendon

Foot ulcers are a severe complication of diabetic patients resulting from nerve and tendon pathologic alterations. In diabetic patients the tendons are thicker, shorter and have increased stiffness. We examined C57BL/KsJ (BKS.Cg-Dock7(m) +/+ Lepr (db) /J) (db/db) mice tendons to determine whether they are an animal model for human diabetic tendon changes. We hypothesized that the Achilles tendons of db/db diabetic mice would be thicker, stiffer, fail at lower loads and stresses, and have degenerative changes compared to control mice. Biomechanical and histologic analyses of the Achilles tendons of 16 week old db/db and control male mice were performed. There was a significant increase in tendon diameter and significant decreases in maximum load, tensile stress, stiffness and elastic modulus in tendons from diabetic mice compared to controls. Mild degenerative and neutrophil infiltration was observed near the tendon insertions on the calcaneous in 25% of db/db mice. In summary, hyper-glycemia and obesity lead to severe changes in db/db mice will be a useful model to examine mechanisms for tendon alterations.

Windlass Mechanism in Individuals With Diabetes Mellitus, Peripheral Neuropathy, and Low Medial Longitudinal Arch Height

BACKGROUND

The windlass mechanism, acting through the plantar fascia, stabilizes the arches of the foot during stance phase of gait. The purpose of this study was to compare changes in radiographic measurements of the medial longitudinal arch (MLA) between toe-flat and -extended positions in participants with and without diabetes mellitus (DM), peripheral neuropathy (PN), and a low MLA.

METHODS

Twelve participants with DMPN and low MLA and 12 controls received weightbearing radiographs in a toe-flat and toe-extended position. DMPN participants were subcategorized from radiographs into DMPN severe, evidence of severe joint changes, and DMPN low, absence of joint changes. Primary measurements of MLA were determined in each position and included Meary's angle, talar declination angle, first metatarsal declination angle, and navicular height.

RESULTS

The DMPN severe group had no difference between toe-flat and -extended positions for Meary's, talar declination, and first metatarsal declination angles (P > .35) while navicular height elevated (P < .05). The DMPN low group had no difference between toe-flat and -extended positions for talar declination angle (P = .38), while Meary's angle, first metatarsal declination angle, and navicular height elevated (P < .05). All measurements in the control group changed, consistent with arch height elevation, when toes were extended (P < .05).

CONCLUSION

The DMPN severe and low groups showed impaired ability to raise the arch from the toe-flat to -extended position. Further research is needed to examine the contribution of specific windlass mechanism components (ie, plantar fascia, ligament, foot joint integrity, and mobility) as they relate to progressive foot deformity in adults with DMPN.

LEVEL OF EVIDENCE

Level III, comparative series.

Diabetic foot and exercise therapy: step by step the role of rigid posture and biomechanics treatment

Lower extremity ulcers represent a serious and costly complication of diabetes mellitus. Many factors contribute to the development of diabetic foot. Peripheral neuropathy and peripheral vascular disease are the main causes of foot ulceration and contribute in turn to the growth of additional risk factors such as limited joint mobility, muscular alterations and foot deformities. Moreover, a deficit of balance, posture and biomechanics can be present, in particular in patients at high risk for ulceration. The result of this process may be the development of a vicious cycle which leads to abnormal distribution of the foot's plantar pressures in static and dynamic postural conditions. This review shows that some of these risk factors significantly improve after a few weeks of exercise therapy (ET) intervention. Accordingly it has been suggested that ET can be an important weapon in the prevention of foot ulcer. The aim of ET can relate to one or more alterations typically found in diabetic patients, although greater attention should be paid to the evaluation and possible correction of body balance, rigid posture and biomechanics. Some of the most important limitations of ET are difficult access to therapy, patient compliance and the transitoriness of the results if the training stops. Many proposals have been made to overcome such limitations. In particular, it is important that specialized centers offer the opportunity to participate in ET and during the treatment the team should work to change the patient's lifestyle by improving the execution of appropriate daily physical activity.

Comparison of foot segmental mobility and coupling during gait between patients with diabetes mellitus with and without neuropathy and adults without diabetes

BACKGROUND

Reduction in foot mobility has been identified as a key factor of altered foot biomechanics in individuals with diabetes mellitus. This study aimed at comparing in vivo segmental foot kinematics and coupling in patients with diabetes with and without neuropathy to control adults.

METHODS

Foot mobility of 13 diabetic patients with neuropathy, 13 diabetic patients without neuropathy and 13 non-diabetic persons was measured using an integrated measurement set-up including a plantar pressure platform and 3D motion analysis system. In this age-, sex- and walking speed matched comparative study; differences in range of motion quantified with the Rizzoli multisegment foot model throughout different phases of the gait cycle were analysed using one-way repeated measures analysis of variance (ANOVA). Coupling was assessed with cross-correlation techniques.

FINDINGS

Both cohorts with diabetes showed significantly lower motion values as compared to the control group. Transverse and sagittal plane motion was predominantly affected with often lower range of motion values found in the group with neuropathy compared to the diabetes group without neuropathy. Most significant changes were observed during propulsion (both diabetic groups) and swing phase (predominantly diabetic neuropathic group). A trend of lower cross-correlations between segments was observed in the cohorts with diabetes.

INTERPRETATION

Our findings suggest an alteration in segmental kinematics and coupling during walking in diabetic patients with and without neuropathy. Future studies should integrate other biomechanical measurements as it is believed to provide additional insight into neural and mechanical deficits associated to the foot in diabetes.

Morphofunctional characteristics of the foot in patients with diabetes mellitus and diabetic neuropathy

AIMS

To determine the structural and biomechanical characteristics associated with the conditions diabetes mellitus and diabetic neuropathy.

METHODS

Observational study of 788 patients conducted between February 2007 and February 2009, which included subjects with and without diabetes mellitus who had no active ulcer at enrollment. Demographic variables and the general and specific history of diabetes mellitus were recorded. The patient's foot type according to the Foot Posture Index, joint mobility and deformity were recorded.

RESULTS

No associations were found between the different foot types (neutral, pronated and supinated) and the structural and demographic variables at a general level, except for the pronated foot that was associated with a higher body mass index, longer suffering from diabetes and the presence of neuropathy [p<0.001, OR (95% CI): 6.017 (4.198-8.624); p<0.001, OR (95% CI): 1.710 (1.266-2.309); p=0.010, OR (95% CI): 0.759 (0.615-0.937), respectively].

CONCLUSIONS

The confluence of risk factors such as neuropathy, body mass index, duration of diabetes and limited joint mobility in patients with diabetes mellitus and pronated foot may be a high-risk anthropometric pattern for developing associated complications such as Charcot foot. A prospective analysis of these patients is required to define the risk for developing Charcot neuroarthropathy.

Do the biomechanical properties of the ankle-foot complex influence postural control for people with Type 2 diabetes?

BACKGROUND

The ankle-foot complex plays an important role in the mechanics of postural control. The objectives of this study were to compare the biomechanical properties of the ankle-foot complex of people with diabetes who had or did not have peripheral neuropathy with those healthy individuals; and to examine its correlation with postural control.

METHODS

A total of 64 individuals participated in this study: 9 people with diabetic peripheral neuropathy, 23 diabetes without neuropathy, and 32 healthy controls. A hand-held ultrasound indentation system was used to assess the soft tissue biomechanical properties of the ankle-foot complex. The Sensory Organization test was performed using The Smart EquiTest system to assess postural control.

FINDINGS

The soft tissue of the Achilles tendon was significantly thickened in all individuals with diabetes (P<0.001), and was associated with the vestibular ratio (r=0.40; P<0.05). The Young's modulus of the plantar soft tissue was significantly increased in the diabetic neuropathy group (all P<0.05). Also, the Young's modulus of the plantar soft tissue at the first metatarsal head was positively correlated with the somatosensory ratio (r=0.46; P<0.05) and visual ratio (r=0.39; P<0.05).

INTERPRETATION

Diabetic patients with or without neuropathy had a thicker Achilles tendon and stiffer plantar soft tissue than the healthy control. Changes in the biomechanical properties of the ankle-foot complex were correlated with the use of vestibular, somatosensory or visual inputs to maintain balance in individuals with diabetes.

Double row anchor fixation: a novel technique for a diabetic calanceal insufficiency avulsion fracture

Avulsion fractures of the calcaneal tuberosity represent only 1.3% to 2.7% of calcaneal fractures. These fractures are common pathologically in nature and attributed to decreased bone mineral density. Calcaneal insufficiency avulsion (CIA) fracture in patients with diabetes mellitus is most likely due to Charcot neuroarthropathy (CN) as described by the Brodsky classification (Brodsky 3B). Traditional open reduction and internal fixation is difficult in all calcaneal avulsion fractures because of poor bone quality. The authors report the first known description of the use of fracture fragment excision and double row anchor fixation.A 39-year-old woman with type I diabetes mellitus and a history of CN presented with an avulsion fracture of the calcaneal tuberosity. Excision of the fracture fragment and a gastrocnemius recession and reattachment of the Achilles tendon with double row anchor fixation to the calcaneus were performed. At 1 year, the patient's American Orthopaedic Foot & Ankle Society rearfoot score improved from 27/100 to 88/100. CIA fractures are an infrequently described injury. Because diabetes mellitus is frequently associated with this disease, it most likely represents a CN event. Traditionally, CIA fractures have been operatively treated with open reduction internal fixation. Previous authors have described difficulty with fixation because of poor quality. In the current report, the authors describe a novel operative approach to CIA fractures through the use of double row anchor fixation and excision of the fracture fragments. The authors feel that this previously undescribed treatment is superior to traditional methods and may serve as a new treatment option for all patients who have sustained this unusual pathology regardless of the underlying cause. The current authors provide a novel operative technique that provides inherent advantages to the traditional repair of CIA fractures. We believe CIA fractures represent a CN-type event and care should be taken when evaluating and treating these patients to prevent further sequelae.

Evaluation and biomechanics of the first ray in the patient with limited motion

Adequate first ray function is essential to healthy human gait. Controversies still exist about aspects of human structure and function and many newer answers and theories have been proposed by a new generation of experts. Examples include the sagittal plane facilitation, tissue stress, and preferred movement pathway theories. This article also presents a summary of how to provide a thorough, detailed, and accurate first ray examination on the individual with limited motion. This article explores functional first ray mechanics in both a theoretic and biomechanical perspective, as well as a practical, hands-on examination perspective.

Plantar enthesopathy: thickening of the enthesis is correlated with energy dissipation of the plantar fat pad during walking

BACKGROUND

The enthesis of the plantar fascia is thought to play an important role in stress dissipation. However, the potential link between entheseal thickening characteristic of enthesopathy and the stress-dissipating properties of the intervening plantar fat pad have not been investigated.

PURPOSE

This study was conducted to identify whether plantar fat pad mechanics explain variance in the thickness of the fascial enthesis in individuals with and without plantar enthesopathy.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

The study population consisted of 9 patients with unilateral plantar enthesopathy and 9 asymptomatic, individually matched controls. The thickness of the enthesis of the symptomatic, asymptomatic, and a matched control limb was acquired using high-resolution ultrasound. The compressive strain of the plantar fat pad during walking was estimated from dynamic lateral radiographs acquired with a multifunction fluoroscopy unit. Peak compressive stress was simultaneously acquired via a pressure platform. Principal viscoelastic parameters were estimated from subsequent stress-strain curves.

RESULTS

The symptomatic fascial enthesis (6.7 ± 2.0 mm) was significantly thicker than the asymptomatic enthesis (4.2 ± 0.4 mm), which in turn was thicker than the enthesis (3.3 ± 0.4 mm) of control limbs (P < .05). There was no significant difference in the mean thickness, peak stress, peak strain, or secant modulus of the plantar fat pad between limbs. However, the energy dissipated by the fat pad during loading and unloading was significantly lower in the symptomatic limb (0.55 ± 0.17) when compared with asymptomatic (0.69 ± 0.13) and control (0.70 ± 0.09) limbs (P < .05). The sonographic thickness of the enthesis was correlated with the energy dissipation ratio of the plantar fat pad (r = .72, P < .05), but only in the symptomatic limb.

CONCLUSION

The energy-dissipating properties of the plantar fat pad are associated with the sonograpic appearance of the enthesis in symptomatic limbs, providing a previously unidentified link between the mechanical behavior of the plantar fat pad and enthesopathy.

The variability of the Achilles tendon insertion: a cadaveric examination

Pathology associated with the Achilles tendon is a common problem, particularly at the site of insertion. A better understanding of the anatomy in this area would assist in developing and fine-tuning treatment options. A cadaveric examination was conducted using 60 human lower extremities (40 cadavers) to determine the location for the terminal insertion site of the Achilles tendon on the posterior aspect of the calcaneus. The average age of the specimens was 67.8 years (range, 43-98 years). Three different investigators examined each specimen, and a consensus as to the site of termination of the Achilles tendon was made. Upon inspection, 55% (22/40) of the limbs had the Achilles tendon inserting on the superior 1/3 aspect of the calcaneus, 40% (16/40) of the limbs inserted on the middle 1/3, and 5% (2/40) of the limbs inserted on the inferior 1/3. The distribution of the insertion was statistically different from random (P = .000371). Further, 8% (3/40) of the specimens revealed a partially contiguous relationship between the Achilles tendon and the plantar fascia. This correlated with the younger specimens (P < .0001). This study provides a better understanding of the anatomical relationship between the Achilles tendon, the calcaneus, and the plantar fascia.

Open calcaneal fractures in diabetic patients with neuropathy: a report of three cases and literature review

Level of Evidence: V, Case Report

Muscle performance and ankle joint mobility in long-term patients with diabetes

Background

Long-term patients with diabetes and peripheral neuropathy show altered foot biomechanics and abnormal foot loading. This study aimed at assessing muscle performance and ankle mobility in such patients under controlled conditions.

Methods

Forty six long-term diabetes patients with (DN) and without (D) peripheral neuropathy, and 21 controls (C) were examined. Lower leg muscle performance and ankle mobility were assessed by means of a dedicated equipment, with the patient seated and the examined limb unloaded. 3D active ranges of motion and moments of force were recorded, the latter during maximal isometric contractions, with the foot blocked in different positions.

Results

All patients showed reduced ankle mobility. In the sagittal and transversal planes reduction vs C was 11% and 20% for D, 20% and 21% for DN, respectively.

Dorsal-flexing moments were significantly reduced in all patients and foot positions, the highest reduction being 28% for D and 37% for DN. Reductions of plantar-flexing moments were in the range 12–15% for D (only with the foot blocked in neutral and in dorsal-flexed position), and in the range 10–24% for DN. In all patients, reductions in the frontal and transversal planes ranged 14–41%.

Conclusion

The investigation revealed ankle functional impairments in patients with diabetes, with or without neuropathy, thus suggesting that other mechanisms besides neuropathy might contribute to alter foot-ankle biomechanics. Such impairments may then play a role in the development of abnormal gait and in the onset of plantar ulcers.

Effect of metatarsal phalangeal joint extension on plantar soft tissue stiffness and thickness

BACKGROUND

Plantar soft tissue stiffness and thickness are important biomechanical variables to understand stress concentrations that may contribute to tissue injury.

OBJECTIVE

The purpose of this study was to determine the effects of passive metatarsal phalangeal joint (MPJ) extension on plantar soft tissue stiffness and thickness.

METHODS

Seventeen healthy participants (7 male, 10 female, mean age 25.3 years, S.D. 4.4 years, mean BMI 24.7 kg/m(2), S.D. 3.2 kg/m(2)) were tested. Plantar soft tissue stiffness and thickness were measured at the metatarsal heads, midfoot and heel using a custom-built indentor device and an ultrasound machine.

RESULTS

Indicators of soft tissue stiffness (K1 values) at the metatarsal heads and midfoot showed increases in stiffness of 81-88% (S.D.20-33%) in the MPJ extension position compared with the MPJ neutral position. Soft tissue thickness measures at the metatarsal heads with the MPJ in neutral ranged from a mean of 8.9 to 13.5mm and decreased, on average, by 8.8% (S.D. 2.9%) with MPJ extension.

CONCLUSIONS

MPJ extension has a profound effect on increasing forefoot plantar soft tissue stiffness and a consistent but minimal effect on reducing soft tissue thickness. These changes may help transform the foot into a rigid lever at push-off consistent with the theory of the windlass mechanism.

Gait characteristics of diabetic patients: a systematic review

Patients with diabetes are at higher risk of experiencing fall-related injuries when walking than healthy controls. The underlying mechanism responsible for this is not yet clear. Thus we intend to summarize diabetic patients' gait characteristics and emphasize those which could be the possible underlying mechanisms for increased fall risk. This systematic review aims, in particular, to: (1) evaluate the quality of existing studies which investigate the gait characteristics of diabetic patients, (2) highlight areas of agreement and contradiction in study results, (3) discuss and emphasize parameters associated with fall risk, and (4) propose new orientations and further domains for research needed for their fall risk prevention. We conducted an electronic search of Pedro, PubMed, Ovid and Cochrane. Two authors independently assessed all abstracts. Quality of the selected articles was scored, and the study results summarized and discussed. We considered 236 abstracts of which 28 entered our full text review. Agreement on data quality between two reviewers was high (kappa: 0.90). Authors investigating gait parameters in a diabetic population evaluated in particular parameters either associated with fall risk (speed, step length or step-time variability) or with ulcers (pressure). There is agreement that diabetic patients walk slower, with greater step variability, and present higher plantar pressure than healthy controls. We concluded that diabetic patients present gait abnormalities, some of which can lead to heightened fall risk. To understand its' underlying mechanisms, and to promote efficient prevention, further studies should analyse gait under 'real-life' conditions.

Plantar fasciitis: are pain and fascial thickness associated with arch shape and loading?

BACKGROUND AND PURPOSE

Although plantar fascial thickening is a sonographic criterion for the diagnosis of plantar fasciitis, the effect of local loading and structural factors on fascial morphology are unknown. The purposes of this study were to compare sonographic measures of fascial thickness and radiographic measures of arch shape and regional loading of the foot during gait in individuals with and without unilateral plantar fasciitis and to investigate potential relationships between these loading and structural factors and the morphology of the plantar fascia in individuals with and without heel pain.

SUBJECTS

The participants were 10 subjects with unilateral plantar fasciitis and 10 matched asymptomatic controls.

METHODS

Heel pain on weight bearing was measured by a visual analog scale. Fascial thickness and static arch angle were determined from bilateral sagittal sonograms and weight-bearing lateral foot roentgenograms. Regional plantar loading was estimated from a pressure plate.

RESULTS

On average, the plantar fascia of the symptomatic limb was thicker than the plantar fascia of the asymptomatic limb (6.1+/-1.4 mm versus 4.2+/-0.5 mm), which, in turn, was thicker than the fascia of the matched control limbs (3.4+/-0.5 mm and 3.5+/-0.6 mm). Pain was correlated with fascial thickness, arch angle, and midfoot loading in the symptomatic foot. Fascial thickness, in turn, was positively correlated with arch angle in symptomatic and asymptomatic feet and with peak regional loading of the midfoot in the symptomatic limb.

DISCUSSION AND CONCLUSION

The findings indicate that fascial thickness and pain in plantar fasciitis are associated with the regional loading and static shape of the arch.

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.