Relationship between changes in activity and plantar ulcer recurrence in a patient with diabetes mellitus

Background and Purpose. Although pressure-reducing interventions have been effective in the healing of neuropathic foot ulcers, these ulcers frequently recur in people with diabetes mellitus (DM). This case report illustrates how sudden changes in weight-bearing activity may have affected ulcer recurrence in a patient with DM and how the physical stress theory (PST) relates to ulcer recurrence for this patient. Case Description. The patient was a 66-year-old man with a history of DM, peripheral neuropathy, and recurrent plantar ulcers. His plantar ulcer healed after total contact casting. Outcome. Despite relatively low peak plantar pressure (9.3 N/cm(2)), the patient's ulcer recurred within 4 weeks of healing. Plantar pressure assessment and activity monitoring suggested that a rapid and sudden increase in weight-bearing activity (steps per day) contributed to cumulative plantar tissue stress that was 3.3 times higher on the day of ulcer recurrence than his average value. Although his cumulative plantar stress was high compared with his usual value, the cumulative value was similar to the amount of daily stress of individuals without a history of recurrent ulcers. Discussion. Within the context of the PST, rapid change in activity level may have an effect on cumulative stress and the risk of ulcer recurrence.