Lower limb biomechanical predictors of neuropathic ulceration in type II diabetes mellitus

Abstract

Diabetes-related foot ulceration is a global leading cause of morbidity and mortality, with peripheral neuropathy being the most significant contributing factor. Research shows that plantar neuropathic ulceration does not necessarily occur on peak pressure areas and other underlying biomechanical factors might be playing a role during gait leading to tissue breakdown. The high prevalence of re-ulceration in patients with diabetic peripheral neuropathy (DPN) shows that current gold standard offloading interventions are not sufficient to prevent and treat ulcers. The purpose of this research was to identify the underlying biomechanical pathomechanism leading to tissue breakdown in the presence of DPN with the aim to propose more specific and individualised methods of ulcer healing and prevention. Four preliminary studies were conducted to provide the groundwork and inform the main quantitative cross-sectional research. The systematic review and meta-analysis results highlighted the significant lower limb musculoskeletal and plantar pressure changes occurring in DPN patients, however, high heterogeneity existed in literature. During Phase II, a mixed-methodological study was performed to explore the local lifestyle challenges met and the current clinical management of this patient population, where the need for a more in-depth biomechanical assessment and management emerged, including a multidisciplinary team of healthcare professionals. Subsequently, a prospective, observational pilot study recruiting 'healthy' participants has shown the significant influence of lower limb joint restriction on the duration of plantar loadings during gait rather than affecting peak pressures. The final preliminary inter-and intra-rater reliability study verifies that the measurements conducted during the main study could be reliably assessed by the researcher when using the formulated standardised protocol. During the main prospective, comparative, non-experimental research conducted in Phase IV, a total of eighty participants (57 male, 23 female, mean age 69.09 years [SD ±8.73], mean BMI 25.13 kg/m2 [SD ± 4.57] fit the inclusion/exclusion criteria and successfully participated in this study to form the four groups, namely; the type 2 diabetes (DM), diabetic peripheral neuropathy (DPN), diabetic neuropathic ulceration (DNU) and history of diabetic neuropathic ulceration (DHNU) groups. An integrated 3-D gait and plantar pressure analysis was performed to identify any significant changes in lower limb and foot joint kinematic, joint kinetic, plantar pressure (mean peak plantar pressure and pressure-time integral data) and spatiotemporal data during gait in the presence of diabetic peripheral neuropathy with or without active ulceration. Participants within the DNU and DHNU groups demonstrated significantly reduced knee and ankle joint dorsiflexion with resultant increased pelvic tilt and hip joint flexion. Significantly reduced kinematics in the shank/calcaneus and first metatarsal joint segments were also observed with resultant increased movement in the midtarsal joint segment. Finally, pressure-time integral data was significantly increased in active/history of forefoot ulceration sites, whereas mean peak plantar pressures were narrowly affected during gait. These findings led to the development of novel, biomechanical ulcer risk models and a clinical pathway as to the underlying pathomechanism leading to ulceration was proposed. Through the integration of a more individualised, biomechanical approach, this new knowledge may improve preventative and management strategies of ulceration, potentially reducing risk of tissue breakdown and amputation rates amongst the diabetic population.