Offloading of Diabetic Neuropathic Plantar Ulcers: Secondary Analysis of Step Activity and Ulcer Healing

Abstract

ABSTRACT OBJECTIVE Although it is well-known that offloading devices facilitate healing in people with diabetes and neuropathic plantar ulcers, little is known about how step activity affects healing. The purposes of this study were to compare: (1) healing outcomes (time to healing, percentage of ulcers healed); (2) healing rates by ulcer location; and (3) step activity (daily step count, daily peak mean cadence) among patients using either total contact casts (TCCs) or removable cast walker boots (RCWs). METHODS The study included 55 participants (TCC, 29; RCW, 26) with diabetes mellitus, peripheral neuropathy, and a Wagner grade 1 or 2 neuropathic plantar ulcer. Each participant wore an activity monitor for 14 consecutive days. Step activity and healing variables were assessed using independent t tests, Kruskal-Wallis, Kaplan-Meier, and Mantel-Cox log-rank tests. RESULTS Mean participant age was 55 (SD, 11) years. The percentage of ulcers healed was lower in the RCW group versus the TCC group (65% vs 93%). If healed, average healing rate was 77 (SD, 48) days in the TCC group and 138 (SD, 143) days in the RCW group. Survival distribution by ulcer location was different for RCW forefoot than other locations (132 ± 13 days vs 91 ± 15, 75 ± 11, and 102 ± 36 days for TCC forefoot, TCC-midfoot/hindfoot, and RCW-midfoot/hindfoot, respectively; χ 2 = 10.69, P = .014). Average step count was 2,597 in the RCW group versus 1,813 steps in the TCC group (P = .07). The daily peak mean cadence for 20-, 30-, or 60-minute periods was greater with RCW use. CONCLUSIONS Step activity in participants with RCWs was increased compared with those with TCCs. Because of their potential to be easily removable, RCWs may impair ulcer healing by allowing greater step activity.