The Importance of Preconditioning for the Sonographic Assessment of Plantar Fascia Thickness and Shear Wave Velocity.

Plantar fasciopathy is a very common musculoskeletal complaint that leads to reduced physical activity and undermines the quality of life of patients. It is associated with changes in plantar fascia structure and biomechanics which are most often observed between the tissue's middle portion and the calcaneal insertion. Sonographic measurements of thickness and shear wave (SW) elastography are useful tools for detecting such changes and guide clinical decision making. However, their accuracy can be compromised by variability in the tissue's loading history. This study investigates the effect of loading history on plantar fascia measurements to conclude whether mitigation measures are needed for more accurate diagnosis. The plantar fasciae of 29 healthy participants were imaged at baseline and after different clinically relevant loading scenarios. The average (±standard deviation) SW velocity was 6.5 m/s (±1.5 m/s) and it significantly increased with loading. Indicatively, five minutes walking increased SW velocity by 14% (95% CI: -1.192, -0.298, t(27), p = 0.005). Thickness between the calcaneal insertion and the middle of the plantar fascia did not change with the tissues' loading history. These findings suggest that preconditioning protocols are crucial for accurate SW elastography assessments of plantar fasciae and have wider implications for the diagnosis and management of plantar fasciopathy.

Reliability of enhanced paper grip test for testing foot strength in volleyball and soccer players.

OBJECTIVES: To evaluate the reliability of the Enhanced Paper Grip Test (EPGT) for assessing foot strength in volleyball and soccer players. DESIGN: A cross-sectional observational study with repeated measurements. SETTING: Field-based study. PARTICIPANTS: A convenience sample of 28 athletes (13 volleyball players and 15 soccer players) participated in the study. MAIN OUTCOME MEASURES: The main outcome measures were the intraclass correlation coefficients (ICC) for intra-visit and inter-visit reliability, typical error, and coefficient of variation for the force (N) recorded in EPGT test. RESULTS: The EPGT demonstrated good to excellent relative reliability (ICC values ranged from 0.93 to 0.97) and acceptable absolute reliability (typical error = 5-8 % of the mean). Significant inter-limb asymmetries were observed in both volleyball (16.0 ± 10.2%) and soccer players (15.3 ± 9.8%). CONCLUSIONS: The EPGT is a reliable tool for assessing foot strength in volleyball and soccer players. Further research is required to explore the applicability of EPGT in different athletic and clinical contexts, and its potential role in athletic performance and injury prevention.

Exploring the Pathways of Diabetes Foot Complications Treatment and Investigating Experiences From Frontline Health Care Professionals: Protocol for a Mixed Methods Study.

BACKGROUND: Diabetes affects more than 4.3 million individuals in the United Kingdom, with 19% to 34% developing diabetes-related foot ulceration (DFU) during their lifespan, which can lead to an amputation. In the United Kingdom, every week, approximately 169 people have an amputation due to diabetes. Preventing first-ever ulcers is the most effective strategy to reduce the occurrence of diabetes-related amputations, but research in this space is lacking. OBJECTIVE: This protocol seeks to document the experiences and perspectives of frontline health care professionals who work with people who have diabetes and diabetes-related foot problems. Special attention is given to their perceptions of barriers to effective care, their views about barriers to effective and inclusive engagement with people with diabetes, and their experience with the first-ever DFU. Another aspect of the study is the focus on whether clinical management is affected by data sharing, data availability, and interoperability issues. METHODS: This is a mixed methods explanatory protocol, which is sequential, and its purpose is to use the qualitative data to explain the initial quantitative data collected through a survey of frontline health care professionals. Data analysis of quantitative data will be completed first and then synthesized with the qualitative data analysis. Qualitative data will be analyzed using the framework method. This study will use joint displays to integrate the data. Ethical approval has been granted by the ethics committee of Staffordshire University. RESULTS: The quantitative data collection started in March 2023 and will close in May 2024. The qualitative interviews commenced in November 2023 with volunteer participants who initially completed the survey. CONCLUSIONS: This study's survey focuses on data interoperability and the interviews focus more on the perspectives and experiences of clinicians and their perceived barriers for the effective management of diabetes foot ulcers. Including a geographically relevant and diverse cohort of health care professionals that spans a wide range of roles and care settings involved in diabetes-related foot care is very important for the successful application of this protocol. Special care is given to advertise and promote participation as widely as possible. The qualitative part of this protocol is also limited to 30-40 interview participants, as it is not realistic to interview higher numbers, due to time and resource constraints. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/54852.

Reliability and Validity of Shore Hardness in Plantar Soft Tissue Biomechanics.

Shore hardness (SH) is a cost-effective and easy-to-use method to assess soft tissue biomechanics. Its use for the plantar soft tissue could enhance the clinical management of conditions such as diabetic foot complications, but its validity and reliability remain unclear. Twenty healthy adults were recruited for this study. Validity and reliability were assessed across six different plantar sites. The validity was assessed against shear wave (SW) elastography (the gold standard). SH was measured by two examiners to assess inter-rater reliability. Testing was repeated following a test/retest study design to assess intra-rater reliability. SH was significantly correlated with SW speed measured in the skin or in the microchamber layer of the first metatarsal head (MetHead), third MetHead and rearfoot. Intraclass correlation coefficients and Bland-Altman plots of limits of agreement indicated satisfactory levels of reliability for these sites. No significant correlation between SH and SW elastography was found for the hallux, 5th MetHead or midfoot. Reliability for these sites was also compromised. SH is a valid and reliable measurement for plantar soft tissue biomechanics in the first MetHead, the third MetHead and the rearfoot. Our results do not support the use of SH for the hallux, 5th MetHead or midfoot.

A quantitative analysis of optimum design for rigid ankle foot orthoses: The effect of thickness and reinforcement design on stiffness.

BACKGROUND: An ankle foot orthosis (AFO) which is prescribed to be rigid should only deform a small amount to achieve its clinical goals. Material thickness and the design of reinforcing features can significantly affect AFO rigidity, but their selection remains based on anecdotal evidence. OBJECTIVES: To quantify the effect of these parameters on AFO stiffness and to set the basis for quantitative guidelines for the design optimisation of rigid AFOs. STUDY DESIGN: Experimental and computational study. METHODS: A polypropylene AFO was produced according to UK standard practice and its stiffness was experimentally measured for 30Nm of dorsiflexion. Its geometry and mechanical characteristics were utilised to create a finite element (FE) model of a typical AFO prescribed to be rigid. Following validation, the model was used to quantify the effect of material thickness and reinforcement design (i.e., reinforcement placement, length) on stiffness. A final set of AFO samples was produced to experimentally confirm key findings. RESULTS AND CONCLUSIONS: For a specific AFO geometry and loading magnitude, there is a thickness threshold below which the AFO cannot effectively resist flexion and buckles. FE modelling showed that stiffness is maximised when reinforcements are placed at the anterior-most position possible. This key finding was also experimentally confirmed. The stiffness of an AFO reinforced according to standard practice with lateral and medial ribbing was 4.4 ± 0.1 Nm/degree. Instructing the orthotic technician to move the ribbings anteriorly increased stiffness by 22%. Further stiffening is achieved by ensuring the reinforcements extend from the footplate to at least two-thirds of the AFO's total height.

The enhanced paper grip test can substantially improve community screening for the risk of falling.

BACKGROUND: Lower-limb strength measures can enhance falls risk assessment but due to the lack of clinically applicable methods, such measures are not included in current screening. The enhanced paper grip test (EPGT) is a simple-to-use and cost-effective test that could fill this gap. However, its outcome measure (EPGT force) has not yet been directly linked to the risk of falling. RESEARCH QUESTION: Is the EPGT a good candidate for falls risk screening in older people in the community? METHODS: Seventy-one older people living independently in the community were recruited for this prospective observational study (median age 69 y, range 65y-79y). Lower-limb and whole-body strength were assessed at baseline using the EPGT and a standardised hand-grip method respectively. Incident falls were recorded monthly for a year through follow-up telephone conversations. The capacity of individual strength measures to predict falls and to enhance an established falls risk assessment tool (FRAT) commonly used by UK's national health service (NHS) was assessed using binomial logistic regression. The analysis was repeated for the subset of participants without history of falling at baseline (prediction of first-ever falls). RESULTS: Increased EPGT force and increased symmetry in strength between limbs were significantly associated with reduced risk of falling. Compared to the NHS-FRAT, the EPGT correctly classified more people (73% vs 69%), it achieved higher sensitivity (56% vs 26%) and higher negative predictive value (76% vs 68%). Complementing the NHS-FRAT with the EPGT produced a more comprehensive model that correctly classified 91% of participants and achieved 98% specificity, 81% sensitivity, 89% negative and 96% positive predictive value. Replacing the EPGT with hand-grip strength consistently undermined prediction accuracy. The EPGT remained highly accurate when focused on the prediction of first-ever falls. SIGNIFICANCE: The EPGT can substantially enhance falls screening in the community. These results can also inform effective personalised strength exercise interventions.

An exploration of the mechanistic link between the enhanced paper grip test and the risk of falling.

The enhanced paper grip test (EPGT) offers an easy-to-use measure of hallux plantar-flexion strength that does not need expensive specialised equipment. Literature suggests that it could be a useful screening tool to assess the risk of falling in older people. However, research on a specific mechanistic link to the risk of falling is lacking. It is hypothesised here that muscle weakening (assessed by the EPGT) is indicative of impaired ability to recover balance after a slip or a trip. To get an initial assessment of validity of the above hypothesis, the EPGT is compared against an established lab-based measure of lower-limb strength that is capable of assessing a person's ability to recover balance after a slip or a trip: maximum isometric leg press push-off force (leg press force). A gender-balanced sample of twenty people (median age=34 y) was recruited. Two different but equaly valid techniques of administering the EPGT were included regarding whether the participants' ankle was supported by the examiner or not. Results for the two EPGT techniques differed susbtantialy but they were both significantly associated with leg press force and therefore linked to better ability to maintain balance after a slip or a trip. The "ankle not held" EPGT technique was more strongly correlated to leg press force (r(18) = 0.652, p = 0.002) than the "ankle held" (r(18) = 0.623, p = 0.003) and appears to be the more favourable technique to administer the EPGT. These findings offer new insight on a potential mechanistic link between the EPGT and the risk of falling and support its optimal use in future research involving older people.

Effective and clinically relevant optimisation of cushioning stiffness to maximise the offloading capacity of diabetic footwear.

INTRODUCTION: Optimising the cushioning stiffness of diabetic footwear/orthoses can significantly enhance their offloading capacity. This study explores whether optimum cushioning stiffness can be predicted using simple demographic and anthropometric parameters. METHODS: Sixty-nine adults with diabetes and loss of protective sensation in their feet were recruited for this cross-sectional observational study. In-shoe plantar pressure was measured using Pedar® for a neutral diabetic shoe (baseline) and after adding cushioning footbeds of varying stiffness. The cushioning stiffness that achieved maximum offloading was identified for each participant. The link between optimum cushioning stiffness and plantar loading or demographic/anthropometric parameters was assessed using multinomial regression. RESULTS: People with higher baseline plantar loading required stiffer cushioning materials for maximum offloading. Using sex, age, weight, height, and shoe-size as covariates correctly predicted the cushioning stiffness that minimised peak pressure across the entire foot, or specifically in the metatarsal heads, midfoot and heel regions in 70%, 72%, 83% and 66% of participants respectively. CONCLUSIONS: Increased plantar loading is associated with the need for stiffer cushioning materials for maximum offloading. Patient-specific optimum cushioning stiffness can be predicted using five simple demographic/anthropometric parameters. These results open the way for methods to optimise cushioning stiffness as part of clinical practice.

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).

Understanding occipital pressure sores in UK military casualties: a pilot study in healthy military personnel.

INTRODUCTION: The high prevalence of occipital ulcers in UK military casualties observed during the conflict in Afghanistan is a multifactorial phenomenon. However, the consensus is that ulceration is triggered by excessive pressure that is maintained for too long during the use of the general service military stretcher. Thresholds for capillary occlusion are accepted benchmarks to define excessive pressure, but similar thresholds for safe/excessive duration of pressure application do not exist. To address this gap in knowledge, we propose to use the time it takes for a healthy person to feel pain at the back of the head as an initial indication of safe exposure to pressure. METHODS: Healthy military personnel (16 male/10 female) were asked to lie motionless on a typical general service stretcher until they felt pain. Time-to-pain and the location of pain were recorded. To support the interpretation of results, baseline sensitivity to pain and pressure distribution at the back of the head were also measured. Independent samples t-test was used to assess differences between genders. RESULTS: Twenty participants felt pressure-induced soft-tissue pain at the back of the head. The remaining six participants terminated the test due to musculoskeletal pain caused by poor ergonomic positioning. On average, pain at the occiput developed after 31 min (±14 min). Female participants were significantly more sensitive to pain (t(24)=3.038,p=0.006), but time-to-pain did not differ significantly between genders (p>0.05). CONCLUSIONS: When people lie motionless on a typical military stretcher, the back of the head is the first area of the body that becomes painful due to pressure. The fact that pain develops in ≈30 min can help healthcare providers decide how frequently to reposition their patients who are unable to do this on their own. More research is still needed to directly link time-to-pain with time-to-injury.

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.

Assessment of the effect of a total contact cast on lower limb kinematics and joint loading.

BACKGROUND: Total contact casts (TCCs) are used to immobilize and unload the foot and ankle for the rehabilitation of ankle fractures and for the management of diabetic foot complications. The kinematic restrictions imposed by TCCs to the foot and ankle also change knee and hip kinematics, however, these changes have not been quantified before. High joint loading is associated with discomfort and increased risk for injuries. To assess joint loading, the effect of the muscle forces acting on each joint must also be considered. This challenge can be overcome with the help of musculoskeletal modelling. RESEARCH QUESTION: How does a TCC affect lower extremity joint loading? METHODS: Twelve healthy participants performed gait trials with and without a TCC. Kinematic and kinetic recordings served as input to subject-specific musculoskeletal models that enabled the computation of joint angles and loading. Cast-leg interaction was modelled by means of reaction forces between a rigid, zero-mass cast segment and the segments of the lower extremity. RESULTS: and Significance: Reduced ankle, knee and hip range of motion was observed for the TCC condition. Statistical parametric mapping indicated decreased hip abduction and flexion moments during initial contact with the TCC. The anterior knee force was significantly decreased during the mid and terminal stance and the second peak of the compressive knee force was significantly reduced for the TCC. As expected, the TCC resulted in significantly reduced ankle loading. SIGNIFICANCE: This study is the first to quantify the effect of a TCC on lower limb joint loading. Its results demonstrate the efficiency of a TCC in unloading the ankle joint complex without increasing the peak loads on knee and hip. Future studies should investigate whether the observed knee and hip kinematic and kinetic differences could lead to discomfort.

Shore hardness is a more representative measurement of bulk tissue biomechanics than of skin biomechanics.

To support the effective use of Shore hardness (SH) in research and clinical practice this study investigates whether SH should be interpreted as a measurement of skin or of bulk tissue biomechanics. A 3D finite element model of the heel and a validated model of a Shore-00 durometer were used to simulate testing for different combinations of stiffness and thickness in the skin and subcutaneous tissue. The results of this numerical analysis showed that SH is significantly more sensitive to changes in skin thickness, relatively to subcutaneous tissue, but equally sensitive to changes in the stiffness of either tissue. Indicatively, 25% reduction in skin thickness (0.3 mm thickness change) or in subcutaneous tissue thickness (5.9 mm thickness change), reduced SH by 7% or increased SH by 2% respectively. At the same time, 25% reduction in skin stiffness (10.1 MPa change in initial shear modulus) or of subcutaneous tissue (4.1 MPa change in initial shear modulus) led to 11% or 8% reduction in SH respectively. In the literature, SH is commonly used to study skin biomechanics. However, this analysis indicates that SH quantifies the deformability of bulk tissue, not of skin. Measurements of skin thickness are also necessary for the correct interpretation of SH.

An in vivo model for overloading-induced soft tissue injury.

This proof-of-concept study demonstrates that repetitive loading to the pain threshold can safely recreate overloading-induced soft tissue damage and that localised tissue stiffening can be a potential marker for injury. This concept was demonstrated here for the soft tissue of the sole of the foot where it was found that repeated loading to the pain threshold led to long-lasting statistically significant stiffening in the overloaded areas. Loading at lower magnitudes did not have the same effect. This method can shed new light on the aetiology of overloading injury in the foot to improve the management of conditions such as diabetic foot ulceration and heel pain syndrome. Moreover, the link between overloading and tissue stiffening, which was demonstrated here for the first time for the plantar soft tissue, opens the way for an assessment of overloading thresholds that is not based on the subjective measurement of pain thresholds.

A quantitative comparison of plantar soft tissue strainability distribution and homogeneity between ulcerated and non-ulcerated patients using ultrasound strain elastography.

The primary objective of this study was to develop a method that allows accurate quantification of plantar soft tissue stiffness distribution and homogeneity. The secondary aim of this study was to investigate if the differences in soft tissue stiffness distribution and homogeneity can be detected between ulcerated and non-ulcerated foot. Novel measures of individual pixel stiffness, named as quantitative strainability (QS) and relative strainability (RS) were developed. Strain Elastography data obtained from 39 (nine with active diabetic foot ulcers) patients with diabetic neuropathy. The patients with active diabetic foot ulcer had wound in parts of the foot other than the first metatarsal head and the heel where the elastography measures were conducted. RS was used to measure changes and gradients in the stiffness distribution of plantar soft tissues in participants with and without active diabetic foot ulcer. The plantar soft tissue homogeneity in superior-inferior direction in the left forefoot was found to be significantly (p < 0.05) higher in ulcerated group compared to non-ulcerated group. The assessment of homogeneity showed potentials to further explain the nature of the change in tissue that can increase internal stress. This can have implications in assessing the vulnerability to plantar soft tissue damage and ulceration in diabetes.

A novel concept for low-cost non-electronic detection of overloading in the foot during activities of daily living.

Identifying areas in the sole of the foot which are routinely overloaded during daily living is extremely important for the management of the diabetic foot. This work showcases the feasibility of reliably detecting overloading using a low-cost non-electronic technique. This technique uses thin-wall structures that change their properties differently when they are repeatedly loaded above or below a tuneable threshold. Flexible hexagonal thin-wall structures were produced using three-dimensional printing, and their mechanical behaviour was assessed before and after repetitive loading at different magnitudes. These structures had an elastic mechanical behaviour until a critical pressure (P crit = 252 kPa ± 17 kPa) beyond which they buckled. Assessing changes in stiffness after simulated use enabled the accurate detection of whether a sample was loaded above or below P crit (sensitivity = 100%, specificity = 100%), with the overloaded samples becoming significantly softer. No specific P crit value was targeted in this study. However, finite-element modelling showed that P crit can be easily raised or lowered, through simple geometrical modifications, to become aligned with established thresholds for overloading (e.g. 200 kPa) or to assess overloading thresholds on a patient-specific basis. Although further research is needed, the results of this study indicate that clinically relevant overloading could indeed be reliably detected without the use of complex electronic in-shoe sensors.

Reliability and validity of an enhanced paper grip test; A simple clinical test for assessing lower limb strength.

BACKGROUND: The paper-grip-test (PGT) involves pulling a small card from underneath the participant's foot while asking them to grip with their hallux. The PGT is shown to be effective in detecting foot muscle-weakening but its outcome is operator-dependent. To overcome this limitation, an enhanced PGT (EPGT) is proposed that replaces the pass/fail outcome of the PGT with a continuous measurement of the pulling force that is needed to remove the card (EPGT-force). RESEARCH QUESTION: Is the EPGT-force an accurate, reliable and clinically applicable measurement of strength? METHODS: Reliability and clinical applicability were examined in two ways. Firstly, two examiners measured EPGT-force for twenty healthy volunteers in a test/retest set-up. EPGT force was measured using a dynamometer, the hallux grip force was measured using a pressure mat. The clinical applicability of the EPGT was tested in ten people with diabetes. Postural sway was also measured. RESULTS: Interclass correlation coefficients (ICC) revealed excellent inter-rater reliability (ICC > 0.75). Intra-rater reliability was excellent for the first examiner (ICC = 0.795) and good for the second (ICC = 0.703). Linear regression analysis indicated that hallux grip force accounted (on average) for 83 %±4 % of the variability in EPGT force. This strong relationship between EPGT force and hallux grip force remained when the test was performed in a clinical setting with the latter accounting for 88 % in EPGT force variability. Spearman rank order correlation showed that people with diabetes with a higher difference in EPGT force between limbs swayed more. SIGNIFICANCE: EPGT force is a reliable and accurate measurement of hallux grip force. Hallux grip force was previously found to be strongly correlated to the strength of all muscle groups of the foot and ankle and to the ability to maintain balance. The proposed EPGT could be used to monitor muscle weakness in clinics for better falls-risk assessment.

Comparative study of the strength characteristics of a novel wood-plastic composite and commonly used synthetic casting materials.

BACKGROUND: Woodcast® is a wood-plastic composite casting material that becomes pliable and self-adhesive when heated to 65 °C and returns to being weightbearing as it cools down. The present study aims to test whether this novel non-toxic casting material is strong enough for clinical use by comparing its strength against materials that are already used in weightbearing casting applications such as total contact casts. METHODS: The strength of Woodcast® samples was compared against the strength of two commonly used synthetic casting materials (Delta-Cast®, OrthoTape). The effect of environmental factors such as cooling, prolonged heating and exposure to water was also assessed. FINDINGS: The results of this study indicated that Woodcast® is stronger than the synthetic casting materials in compression but weaker in tension. The flexural strength of Woodcast® was 14.24 MPa (±1.25 MPa) while the respective strength of Delta-Cast® and OrthoTape was 18.96 MPa (±7.46 MPa) and 12.93 MPa (±1.93 MPa). Independent samples t-test indicated that the difference between Woodcast® and the other two materials was not statistically significant (P > .05). Woodcast® recovered 90% and 78% of its tensile or flexural strength respectively after 15 min of cooling at ambient temperature and its strength was not reduced by prolonged heating. On average, exposure to water reduced the flexural strength of Delta-Cast® by 6% and of OrthoTape by 44%. The strength of Woodcast® was not affected by exposure to water. INTERPRETATION: The comparison between Woodcast® and commonly used synthetic casting materials indicated that Woodcast® is indeed strong enough to be safely used in weightbearing casting applications.

Optimised cushioning in diabetic footwear can significantly enhance their capacity to reduce plantar pressure.

BACKGROUND: Plantar pressure reduction with the use of cushioning materials play an important role in the clinical management of the diabetic foot. Previous studies in people without diabetes have shown that appropriate selection of the stiffness of such materials can significantly enhance their capacity to reduce pressure. However the significance of optimised cushioning has not been yet assessed for people with diabetic foot syndrome. RESEARCH QUESTION: What is the potential benefit of using footwear with optimised cushioning, with regards to plantar pressure reduction, in people with diabetes and peripheral neuropathy? METHODS: Plantar pressure distribution was measured during walking for fifteen people with diabetic foot syndrome in a cohort observational study. The participants were asked to walk in the same type of footwear that was fitted with 3D-printed footbeds. These footbeds were used to change the stiffness of the entire sole-complex of the shoe; from very soft to very stiff. The stiffness that achieved the highest pressure reduction relative to a no-footbed condition was identified as the patient-specific optimum one. RESULTS: The use of the patient-specific optimum stiffness reduced, on average, peak pressure by 46% (±14%). Using the same stiffness across all participants lowered the footwears' capacity for pressure reduction by at least nine percentile points (37% ±â€¯17%); a statistically significant difference (paired samples t-test, t(13) = -3.733, p = 0.003, d = 0.997). Pearson correlation analysis indicated that patient-specific optimum stiffness was significantly correlated with the participants' body mass index (BMI), with stiffer materials needed for people with higher BMI (rs(14) = 0.609, p = 0.021). SIGNIFICANCE: This study offers the first quantitative evidence in support of optimising cushioning in diabetic footwear as part of standard clinical practice. Further research is needed to develop a clinically applicable method to help professionals working with diabetic feet identify the optimum cushioning stiffness on a patient-specific basis.