A single-blinded multicenter randomized controlled trial of shape- and pressure-based in-shoe orthoses manufactured by State College, PA-based DIApedia shows the experimental insole reduced ulcer recurrence significantly better than three standard-of-care orthoses, though the experimental insole had no significant effect on the occurrence of nonulcerative lesions, according to research published April 23 in Diabetes Care.
Investigators from the University of Pennsylvania in Philadelphia and the University of Washington in Seattle led the study, which recruited 130 patients from 11 outpatient clinics who had diabetes, neuropathy, at least one recently healed metatarsal head (MTH) ulcer, and peak barefoot plantar pressure in the area of the previous ulcer greater than 450 kPa. The patients were randomized to intervention with either the experimental insoles (n = 66) or control insoles (n = 64).
Investigators obtained digital scans of foot shape from foam boxes for all foot orthoses used in the study; the experimental orthoses began with a design similar to a “shape-only” orthosis and were then modified using a CAD process following defined algorithms based on peak barefoot plantar pressure distribution contours and designed to offload the MTH region.
Investigators followed patients for 15 months or until they developed a forefoot plantar ulcer or nonulcerative lesion. At 180 days they found a significant ulcer prevention benefit for the experimental orthoses compared with the control insoles. Across the entire follow-up period they found a clear trend for a better composite outcome—the occurrence of ulcers and other lesions—in the experimental group, though not a significant difference in the occurrence of nonulcerative lesions.
The hazard ratio was 3.4 (1.3-8.7) for ulcer recurrence in the control condition relative to the experimental condition, and investigators concluded that custom orthoses based on foot shape and barefoot plantar pressures better prevent ulcer recurrence under the metatarsal heads than those based on foot shape and clinical insight.
Study coauthor Peter Cavanagh, DSc, PhD, Endowed Chair in Women’s Sports Medicine and vice chair of research for Orthopaedics and Sports Medicine at the University of Washington, will discuss the efficacy of insoles based on foot shape and plantar pressures at the upcoming Orthotics Technology Forum, scheduled for June 4-6 in Chicago.