A comparison of the 1-step, 2-step, and 3-step protocols for obtaining barefoot plantar pressure data in the diabetic neuropathic foot

Background. Barefoot plantar pressure measurements are routinely used in the risk evaluation for ulceration in diabetic patients with neuropathy. The aim was to compare three step-protocols commonly used for pressure assessment in these patients. Methods. Dynamic barefoot plantar pressures were measured in 14 diabetic neuropathic patients (vibration perception threshold >35 V) contacting a pressure platform on the first, second or third step after gait initiation. Ten repeated trials per step-protocol were collected. The 3-step protocol was regarded the reference protocol. Peak pressure, pressure-time integral and contact time were calculated for each of six anatomical foot regions. Intraclass correlation coefficients (ICC) were calculated to assess reliability in each protocol. Findings. Regional peak pressures and pressure-time integrals were not significantly different between protocols. Contact time was significantly different in the heel region between the 1-step and 3-step protocol only (P < 0.05). Intraclass correlation coefficients for the maximum 10 repeated trials were high (>0.87) and similar between protocols. Reliable estimates (ICC > 0.85) of peak pressure were achieved with three repeated trials in the 2-step protocol, and four in the other two; for pressure-time integral these numbers were 7 (1-step), 4 (2-step), and 5 trials (3-step). Interpretation. Barefoot plantar pressures in the diabetic neuropathic foot can be assessed in a reproducible manner with any of the step-protocols used. For this purpose, the 1-step and 2-step protocols prove to be valid methods. A 2-step protocol requires the least amount of repeated trials for obtaining reliable pressure data and may be recommended for assessment of these patients