Prevalence of ankle equinus and correlation with foot plantar pressures in people with diabetes

Background: An association between equinus and plantar pressure may be important for people with diabetes, as elevated plantar pressure has been linked with foot ulcer development. To determine the prevalence of equinus in community dwelling people with diabetes and to examine any association between presence of equinus and forefoot plantar pressures. Methods: Barefoot (Tekscan HR Mat™) and in-shoe (Novel Pedar-X®) plantar pressure variables, non-weight bearing ankle range of motion and neuropathy status were assessed in 136 adults with diabetes (52.2% male; 47.8% with neuropathy; mean (standard deviation) age and diabetes duration: 68.4 (11.5) and 14.6 (11.1) years respectively). Findings: Equinus, when measured as ≤5° dorsiflexion, was present in 66.9% of the cohort. There was a significant correlation between an equinus and barefoot (r = 0.247, p = 0.004) and in-shoe forefoot pressure time integrals (r = 0.214, p = 0.012) and in-shoe forefoot alternate pressure time integrals (r = 0.246, p = 0.004). Significantly more males (p < 0.01) and people with neuropathy (p = 0.02) or higher glycated haemoglobin levels (p < 0.01) presented with an equinus. Interpretation: Community dwelling adults with diabetes have a high rate of ankle equinus which is associated with increased forefoot pressure time integrals and a two-fold increased risk of high in-shoe peak pressures. Clinical assessment of an ankle equinus may be a useful screening tool to identify adults at increased risk of diabetic foot complications.