518-P: Prior to Development of Neuropathy, People with Diabetes Have Altered Morphological and Mechanical Properties of the Ankle Joint, Tendons, and Muscles

Diabetes-related anatomical changes to the foot that foment ulcer formation are attributed to diabetic neuropathy. We hypothesized that prior to development of neuropathy, diabetes is associated with biomechanical changes in the ankle joint. To test this hypothesis, morphological properties of Achilles tendon, soleus, medial and lateral gastrocnemius muscles were evaluated by a LOGIQ ultrasound device at preset ankle (−30, −15,0,10) and knee (90,180) positions in both subjects with diabetes without neuropathy (DM; n=11, age 53±11, 3M, 8F, 87±16 kg, HbA1c 7.37±1.80, disease duration 75±79 months) and nondiabetic controls (CON; n=12, age 45±17, 5M, 7F, 75±14 kg). Monofilament (5.07/10 g) testing confirmed absence of neuropathy. As compared to CON, DM demonstrated significantly shorter Achilles length (p=0.002), smaller cross section area (p=0.018), higher Achilles stiffness (p=0.006), shorter muscle fascicles across the soleus muscle (p=0.03), higher stiffness in the soleus (p=0.001) and lateral gastrocnemius (p=0.002), and higher pennation angles for all three muscles (p<0.05). The current study demonstrates altered muscle-tendon unit mechanical properties in subjects with diabetes without neuropathy. These changes indicate a pathological process that may contribute to plantar ulcer formation even in absence of diabetic neuropathy.