Foot Biomechanics in Patients with Diabetes Mellitus Doubts Regarding the Relationship Between Neuropathy, Foot Motion, and Deformities

Background: We sought to identify the biomechanical characteristics of the feet of patients with diabetes mellitus and the interrelationship with diabetic neuropathy by determining the range of joint mobility and the presence and locations of calluses and foot deformities. Methods: This observational comparative study involved 281 patients with diabetes mellitus who underwent neurologic and vascular examinations. Joint mobility studies were performed, and deformities and hyperkeratosis locations were assessed. Results: No substantial differences were found between patients with and without neuropathy in joint mobility range. Neuropathy was seen as a risk factor only in the passive range of motion of the first metatarsophalangeal joint (mean +/- SD: 57.2 degrees +/- 19.5 degrees versus 50.3 degrees +/- 22.5 degrees, P = .008). Mean +/- SD ankle joint mobility values were similar in both groups (83.0 degrees +/- 5.2 degrees versus 82.8 degrees +/- 9.3 degrees, P = .826). Patients without neuropathy had a higher rate of foot deformities such as hallux abductus valgus and hammer toes. There was also a higher presence of calluses in patients without neuropathy (82.8% versus 72.6%; P = .039). Conclusions: Diabetic neuropathy was not related to limited joint mobility and the presence of calluses. Patients with neuropathy did not show a higher risk of any of the deformities examined. These findings suggest that the etiology of biomechanical alterations in diabetic people is complex and may involve several anatomically and pathologically predisposing factors. (J Am Podiatr Med Assoc 101(3): 208-214, 2011)