Do people who load their feet differently need insoles that have different stiffness?

Background: Plantar pressure reduction is an important aspect of diabetic foot management. However little information exists about the optimum cushioning properties of materials used in diabetic footwear as insoles/foot-beds. Numerical analyses have indicated that optimizing the material properties of footwear materials can improve their ability to reduce pressure. Aim: To investigate if the optimal insole stiffness would vary based on patients’ body mass (BM) in people with diabetic neuropathy. Method: Custom PU foams were produced using different ratios of chemical components to achieve a range of different stiffness. Uniform thickness (400 mm × 400 mm × 10 mm) foam sheets were produced with shore-A hardness between 3 and 45 and average(±stdev) increments of 5(±3). Standardized compression tests were performed for all 10 custom materials as well as for 3 commercially available foam materials used in diabetic footwear. Plantar pressure was measured during balanced standing on all custom material sheets for 4 diabetic neuropathic volunteers: 2 with BM of 49 kg ± 1 kg and 2 with BM of 73 kg ± 2 kg. Results: The maximum compressive force for 50% compression of the commercially available foams was similar to custom foams with 11–28 shore-A hardness. Peak plantar pressure was minimised for materials with shore-A hardness 6 and 11 in subjects with BM of 49 kg ± 1 kg and 73 kg ± 2 kg respectively. In all cases using softer or stiffer material (by 1 shore hardness increment) increased pressure by 24% ± 26% and 32% ± 34% respectively. Conclusions: Careful selection of insole/foot-bed stiffness can improve the pressure reduction capacity of diabetic footwear. Optimum material stiffness increased with the BM of the volunteers

Automated Method for Tracking Human Muscle Architecture on Ultrasound Scans during Dynamic Tasks

Existing approaches for automated tracking of fascicle length (FL) and pennation angle (PA) rely on the presence of a single, user-defined fascicle (feature tracking) or on the presence of a specific intensity pattern (feature detection) across all the recorded ultrasound images. These prerequisites are seldom met during large dynamic muscle movements or for deeper muscles that are difficult to image. Deep-learning approaches are not affected by these issues, but their applicability is restricted by their need for large, manually analyzed training data sets. To address these limitations, the present study proposes a novel approach that tracks changes in FL and PA based on the distortion pattern within the fascicle band. The results indicated a satisfactory level of agreement between manual and automated measurements made with the proposed method. When compared against feature tracking and feature detection methods, the proposed method achieved the lowest average root mean squared error for FL and the second lowest for PA. The strength of the proposed approach is that the quantification process does not require a training data set and it can take place even when it is not possible to track a single fascicle or observe a specific intensity pattern on the ultrasound recording

Screening for the loss of protective sensation in people without a history of diabetic foot ulceration: Validation of two simple tests in India

The ability of the Ipswich touch test (IpTT) and VibratipTM to detect loss of protective sensation (LOPS) was tested against a neurothesiometer in an outpatient diabetic population without a history for ulceration. Our results support the use of the IpTT as a screening tool for LOPS, but not of VibratipTM

Supersonic shear wave elastography of human tendons is associated with in vivo tendon stiffness over small strains

Supersonic shear wave (SW) elastography has emerged as a useful imaging modality offering researchers and clinicians a fast, non-invasive, quantitative assessment of tendon biomechanics. However, the exact relationship between SW speed and in vivo tendon stiffness is not intuitively obvious and needs to be verified. This study aimed to explore the validity of supersonic SW elastography against a gold standard method to measure the Achilles tendon's in vivo tensile stiffness by combining conventional ultrasound imaging with dynamometry. Twelve healthy participants performed maximal voluntary isometric plantarflexion contractions (MVC) on a dynamometer with simultaneous ultrasonographic recording of the medial gastrocnemius musculotendinous junction for dynamometry-based measurement of stiffness. The tendon's force–elongation relationship and stress–strain behaviour were assessed. Tendon stiffness at different levels of tension was calculated as the slope of the stress–strain graph. SW speed was measured at the midportion of the free tendon and tendon Young's modulus was estimated. A correlation analysis between the two techniques revealed a statistically significant correlation for small strains (r(10) = 0.604, p =.038). SW-based assessments of in vivo tendon stiffness were not correlated to the gold standard method for strains in the tendon>10 % of the maximum strain during MVC. The absolute values of SW-based Young's modulus estimations were approximately-three orders of magnitude lower than dynamometry-based measurements. Supersonic SW elastography should be only used to assess SW speed for the detection and study of differences between tissue regions, differences between people or groups of people or changes over time in tendon initial stiffness (i.e., stiffness for small strains)

Can plantar soft tissue mechanics enhance prognosis of diabetic foot ulcer?

AimTo investigate if the assessment of the mechanical properties of plantar soft tissue can increase the accuracy of predicting Diabetic Foot Ulceration (DFU).Methods40 patients with diabetic neuropathy and no DFU were recruited. Commonly assessed clinical parameters along with plantar soft tissue stiffness and thickness were measured at baseline using ultrasound elastography technique. 7 patients developed foot ulceration during a 12 months follow-up. Logistic regression was used to identify parameters that contribute to predicting the DFU incidence. The effect of using parameters related to the mechanical behaviour of plantar soft tissue on the specificity, sensitivity, prediction strength and accuracy of the predicting models for DFU was assessed.ResultsPatients with higher plantar soft tissue thickness and lower stiffness at the 1st Metatarsal head area showed an increased risk of DFU. Adding plantar soft tissue stiffness and thickness to the model improved its specificity (by 3%), sensitivity (by 14%), prediction accuracy (by 5%) and prognosis strength (by 1%). The model containing all predictors was able to effectively (χ2 (8, N = 40) = 17.55, P < 0.05) distinguish between the patients with and without DFU incidence.ConclusionThe mechanical properties of plantar soft tissue can be used to improve the predictability of DFU in moderate/high risk patients