Investigation of Shore meter in assessing foot sole hardness in patients with diabetes mellitus - a pilot study

Diabetic foot ulcers, their characteristics, and trends in survival: Real world outcomes at a tertiary care facility in India

AIMS

Characteristics of diabetes-related foot ulcers (DFU), association with recurrence and amputation are poorly described in the Asian Indian population.

METHODS

A prospectively maintained database was reviewed to characterize DFU and its association with amputation and recurrence.

RESULTS

Of 200 patients, 63.5 % were male, the median age was 62 years (Min-Max:40-86), and median BMI was 27.90 kg/m2 (Min-Max:18.5-42.7). Median duration of Diabetes mellitus was 15 years (Min-Max:2-43). Complete healing occurred at a median of three months (Min-Max:0.23-37.62). Amputation for the current ulcer was required in 43.4 % of individuals. Ulcer recurrence was documented in 42.4 % instances, 66.1 % evolving on the ipsilateral side. Previous amputation was associated with the risk of subsequent amputation (Adjusted OR-3.08,p-0.047). Median time to ulcer recurrence was 4.23 years among those with amputation, in contrast to 9.61 years in those with healing. Cardiovascular death was the commonest cause of mortality, followed by sepsis. At a median follow up of 6.08 years, mortality at 1,3,5 and 10 years was 2.5 %,2.5 %,8.2 % and 30.9 % respectively among those who underwent amputation versus 0 %,0 %,10.1 % and 24.5 % respectively for those who achieved healing.

CONCLUSIONS

Patients with DFU in India incur amputations at rates higher than conventionally described. With previous amputation, subsequent amputation risk triples. Ten-year mortality is 25%-30 %. Underestimates of the burden of recurrence and mortality are consequential of limited follow-up.

Assessing reliability and validity of different stiffness measurement tools on a multi-layered phantom tissue model

Changes in the mechanical properties (i.e., stiffness) of soft tissues have been linked to musculoskeletal disorders, pain conditions, and cancer biology, leading to a rising demand for diagnostic methods. Despite the general availability of different stiffness measurement tools, it is unclear as to which are best suited for different tissue types and the related measurement depths. The study aimed to compare different stiffness measurement tools' (SMT) reliability on a multi-layered phantom tissue model (MPTM). A polyurethane MPTM simulated the four layers of the thoracolumbar region: cutis (CUT), subcutaneous connective tissue (SCT), fascia profunda (FPR), and erector spinae (ERS), with varying stiffness parameters. Evaluated stiffness measurement tools included Shore Durometer, Semi-Electronic Tissue Compliance Meter (STCM), IndentoPRO, MyotonPRO, and ultrasound imaging. Measurements were made by two independent, blinded examiners. Shore Durometer, STCM, IndentoPRO, and MyotonPRO reliably detected stiffness changes in three of the four MPTM layers, but not in the thin (1 mm thick) layer simulating FPR. With ultrasound imaging, only stiffness changes in layers thicker than 3 mm could be measured reliably. Significant correlations ranging from 0.70 to 0.98 (all p < 0.01) were found. The interrater reliability ranged from good to excellent (ICC(2,2) = 0.75-0.98). The results are encouraging for researchers and clinical practitioners as the investigated stiffness measurement tools are easy-to-use and comparatively affordable.

Relationship Between Plantar Tissue Hardness and Plantar Pressure Distributions in People With Diabetic Peripheral Neuropathy

Objective: People with diabetic peripheral neuropathy (DPN) are usually accompanied with increased plantar pressure. Such high plantar loading during daily activities may cause changes in the biomechanical properties of plantar soft tissue, whose viability is critical to the development of foot ulcers. This study aimed to investigate the relationship between plantar tissue hardness and plantar pressure in people with and without DPN, and preliminarily explore the influence of plantar loading patterns on the plantar pressure and tissue hardness.

Methods: The study was conducted on 14 people with DPN and 14 diabetic people without DPN. The Shore durometer and MatScan System were used to measure the plantar tissue hardness and plantar pressure, respectively. The plantar loading level was evaluated by the duration of daily weight-bearing activity and was used to group diabetic participants with and without DPN into two subgroups (lower loading group and higher loading group).

Results: The plantar tissue hardness was significantly correlated with static peak plantar pressure (PPP, p < 0.05) and dynamic pressure-time integral (PTI, p < 0.05) in the forefoot region in people with DPN. Results of variance analysis showed a significant interaction effect between peripheral neuropathy and plantar loading on tissue hardness (p < 0.05), but not plantar pressure. For people with DPN, significant differences in tissue hardness between the higher loading group and lower loading group were observed in the forefoot, midfoot and hindfoot regions. In the higher loading group, people with DPN had significantly greater tissue hardness than that in people without DPN in the toes, forefoot, midfoot and hindfoot regions (p < 0.05).

Conclusions: There is a significant correlation between tissue hardness and PPP, and between tissue hardness and PTI in people with DPN. Plantar loading associated with daily activities plays a significant role on the plantar tissue hardness in people with DPN. The findings of this study contribute to further understand the relationship between increased plantar tissue hardness and high plantar pressure in people with diabetic peripheral neuropathy.

The effects of different accumulated pressure-time integral stimuli on plantar blood flow in people with diabetes mellitus

Background

Exercise, especially weight-bearing exercise (e.g. walking), may affect plantar tissue viability due to prolonged repetitive high vertical and high shear pressure stimulus on the plantar tissue, and further induce development of diabetic foot ulcers (DFUs). This study aimed to investigate the effects of different accumulated pressure-time integral (APTI) stimuli induced by walking on plantar skin blood flow (SBF) responses in people with diabetes mellitus (DM).

Methods

A repeated measures design was used in this study. Two walking protocols (low APTI (73,000 kPa·s) and high APTI (73,000 × 1.5 kPa·s)) were randomly assigned to ten people with DM and twenty people without DM. The ratio of SBF measured by laser Doppler flowmetry after walking to that before (normalized SBF) was used to express the SBF responses.

Results

After low APTI, plantar SBF of people with DM showed a similar response to people without DM (P = 0.91). However, after high APTI, people with DM had a significantly lower plantar SBF compared to people without DM (P < 0.05). In people with DM, plantar SBF in the first 2 min after both APTI stimuli significantly decreased compared to plantar SBF before walking (P < 0.05).

Conclusions

People with DM had a normal SBF response after low APTI walking but had an impaired SBF response after high APTI walking, which suggests that they should avoid weight-bearing physical activity with intensity more than 73,000 kPa·s and should rest for more than 2 min after weight-bearing physical activity to allow a full vasodilatory response to reduce risk of DFUs.

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.

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.

Plantar blood flow response to accumulated pressure stimulus in diabetic people with different peak plantar pressure: a non-randomized clinical trial

The aim of this study was to investigate the plantar blood flow response to the same accumulated pressure stimulus in diabetic patients with different peak plantar pressure (PPP), which is important for assessing the risk of diabetic foot ulcer. Eleven diabetic subjects with high PPP (PPP ≥ 207 kPa) and 8 diabetic subjects with low PPP (PPP < 207 kPa) were asked to walk naturally on a treadmill so as to induce an accumulated stimulus of 73,000 kPa·s on their first metatarsal head, which was monitored with a sensorized insole. Blood perfusion (BP) in the first metatarsal head was measured before and after walking. Results showed that blood flow after applying the same walking stimulus was significantly decreased in comparison to the basal BP before walking in both high PPP and low PPP groups (p < 0.05), but no significant differences were found between the two groups in terms of BP parameters and its percentage change (p > 0.05). Moreover, BP parameters were not significantly correlated to PPP and the pressure-time integral (PTI) of the subjects' gait (p > 0.05). This indicated that, besides PPP and PTI, the accumulated mechanical stimulus should be taken into consideration when assessing the risk of diabetic patients developing foot ulcers. Graphical abstract Plantar blood flow response to a walking stimulus.