Objective: To investigate the role of limited joint mobility (LJM) in causing abnormal foot pressures and foot ulceration.
Research design and methods: The subjects were recruited from a general diabetes clinic where patients were screened for neuropathy, retinopathy, and elevated plantar foot pressure. Sixty-four patients in five groups were matched by age and sex in the following groups: group 1, patients with LJM and neuropathy; group 2, nonneuropathic diabetic patients with LJM; group 3, patients with neuropathy and no LJM; group 4, diabetic control subjects; and group 5, nondiabetic control subjects. Joint mobility was assessed in the foot at subtalar and metatarsophalangeal joints; plantar foot pressures were assessed by optical pedobarography and neuropathic status by a Biothesiometer and electrophysiology.
Results: Joint mobility was reduced at both sites in groups 1 and 2 compared with groups 3, 4, and 5 (P less than 0.001). Plantar foot pressures were significantly higher in groups 1 and 2 compared with groups 3, 4, and 5 (P less than 0.001). No differences in plantar foot pressures were observed between groups 1 and 2. There were strong correlations between plantar foot pressures and joint mobility in the foot (r = -0.7, P less than 0.001). Previous foot ulceration was present in 65% of patients in group 1, none in group 2, and 5% in group 3.
Conclusions: 1) LJM may be a major factor in causing abnormally high plantar foot pressures, 2) abnormal plantar foot pressures alone do not lead to foot ulceration, and 3) LJM contributes to foot ulceration in the susceptible neuropathic foot.