Risk of Foot Ulcer Development in Diabetic Patients – Relation to Isokinetic Muscle Strength, Sensory Function, and Clinical Findings

Aim : To investigate whether reduced muscle strength in the lower extremities in diabetic patients is associated to the development of Diabetic Foot Ulcer (DFU). Methods : We conducted a retrospective cohort study on 95 diabetic patients who participated in studies on Diabetic Polyneuropathy (DPN) and motor function 12–16 years earlier. Isokinetic muscle strength at the ankle and knee, Neurological Impairment Scores (NIS), vibration perception thresholds (VPT), and demographic data were obtained from the initial studies. Patient files were systematically reviewed, and information on DFU occurrence and Macrovascular Disease (MVD) acquired. Results : Twenty-six patients developed DFU. A temporal relationship was found for development of DFU among patients with reduced strength at both the ankle and knee (all P<0.05). Univariate analyses showed a relationship between DFU and reduced strength for ankle dorsal flexion (P<0.001), ankle plantar flexion (P<0.005), knee extension (P<0.001), and knee flexion (P<0.005). DFU was related to NIS (P<0.001) and MVD (P<0.05) in both univariate and multivariate regression analyses. After adjustment for MVD, all strength measures were related to DFU. When adjusting for NIS, a trend was only found for ankle dorsal flexion (P=0.08). Conclusions : In DPN, muscle weakness at the ankle and knee contributes to development of foot ulcers.