Poster 299: Off-Loading Effect of Patella-Tendon-Bearing Ankle Foot Orthosis in Patients With Diabetic Charcot Neuroarthropathic Foot: A Pilot Study With 12 Months Follow-Up

Abstract

Objective: To evaluate the off-loading effect of patella-tendon-bearing ankle foot orthosis (PTB/AFO) in patients with diabetic Charcot neuroarthropathic foot (DCNA) over 12 months. Design: Retrospective review of serial pedobarometric measurement in 6 patients with diabetic Charcot neuroarthropathic foot wearing PTB/AFO over 12 months. Setting: Diabetic foot and ankle clinic in tertiary hospital. Participants: 6 patients with DCNA treated with PTB/AFO (anterior and posterior shells encompassing the calf muscles with double uprights attached to custom made shoe). Interventions: Not applicable. Main Outcome Measures: Serial measurement of pedobarometric parameters, peak plantar pressure (PPPr) and force-time integral (FTI), at 2 weeks, 3, 6, and 12 months after application of PTB/AFO. Wilcoxon matched-pairs signed-rank test was used for analysis. Results: The median PPPr on the entire foot was reduced from 312.2kPa with Darco shoe to 140.7kPa with PTB/AFO at 2 weeks (54.9% reduction), 174.5kPa at 3 months, 175.8kPa at 6 months, and 175.5kPa at 12 months (43.7% reduction) after application. The difference in median PPPr at 2 weeks and 12 months approached statistical significance (P=0.0625). The median FTI of the entire foot was reduced from 636.2 newton seconds (Nsec) with Darco shoe to 469.9Nsec with PTB AFO at 2 weeks (26.1% reduction), 548.2Nsec at 3 months (13.8% reduction), 555.9Nsec at 6 months (12.6% reduction) and 570.1Nsec at 12 months (10.4% reduction). The median FTI at 12 months was significantly different from that at 2 weeks for hindfoot (P=0.031). The largest reduction in off-loading effect was seen between 2 weeks and 3 months. Conclusions: The initial off-loading ability of PTB/AFO in patients with DCNA foot is not maintained with substantial reduction over 12 months. Considering the largest reduction was observed during the first 3 months, adjustment of fitting is recommended during this period.