Optimised cushioning provided by newly developed 3D printed insoles in diabetic footwear can significantly enhance their capacity to reduce plantar pressure, a new study concludes. This research was published in Gait and Posture, the official journal of the Gait and Clinical Movement Analysis Society (GCMAS), the European Society of Movement Analysis in Adults and Children (ESMAC), Società Italiana di Analisi del Movimento in Clinica (SIAMOC), and the International Society for Posture and Gait Research (ISPGR).
“This study offers the first quantitative evidence in support of optimising cushioning in diabetic footwear as part of standard clinical practice,” first author Panagiotis E Chatzistergos (Centre for Biomechanics and Rehabilitation Technologies, Staffordshire University, Stoke-on-Trent, UK) and colleagues write. However, they note that 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”.
As the significance of optimised cushioning had not yet been assessed for people with diabetic foot syndrome, and as earlier studies in people without diabetes have shown that appropriate selection of insole stiffness can significantly enhance their capacity to reduce pressure, the study investigators set out to determine if there was a potential benefit of using footwear with this type of cushioning in people with diabetes and peripheral neuropathy.
“Optimising” the cushioning involves tailoring the insoles used to each specific patient. In particular, selecting the correct insole stiffness led to statistically significant improvements in pressure reduction. Stiffer cushioning materials were needed for those patients with a greater body mass index (BMI) score due to higher magnitudes of loading.
Chatzistergos reportedly comments: “The optimum stiffness is clearly related to the patient’s BMI. This study adds to our earlier findings and concludes that stiffer materials are needed for people with a higher BMI.”
Chatzistergos et al measured the plantar pressure distribution during walking for fifteen people with diabetic foot syndrome in their cohort observational study. The participants were asked to walk in the same type of footwear that was fitted with 3D-printed insoles. The authors explain: “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.”
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 capacity of the footwear for pressure reduction by at least nine percentile points (37±17%); a statistically significant difference (p=0.003). The researchers further identified that patient-specific optimum stiffness was significantly correlated with the participants’ BMI, with stiffer materials needed for people with a higher BMI (p=0.021).
Nachi Chockalingam, director of Staffordshire University’s Centre for Biomechanics and Rehabilitation Technologies and co-inventor of the insole technology, says: “With numerous patients losing their limbs to diabetic foot disease, our research will help clinicians effectively manage this disease.”