Dynamic Ankle Orthosis Improved Patient Comfort During Extended Wear Compared To A Orthopedic Walking Boot

Tibial bone stress injuries (TBSI) are common in military trainees (29-74%) and recreational runners (21.9%). Clinicians prescribe an orthopedic walking boots (WB) for daily use for 3-26 weeks. WB rigid design results in reduced ankle mobility, decreased muscle activity, and muscle atrophy within 4 days of boot wear, delaying recovery. A newly developed custom Dynamic Ankle Orthosis (DAO) applies a distractive force that reduces vertical in-shoe force and tibial compressive force while retaining unbraced ankle motion during walking. PURPOSE: To assess the comfort level of the DAO during extended wear in healthy adults during daily walking activities. METHODS: Ten healthy participants performed four walking activities at a preferred walking pace in two brace conditions: DAO and WB. Force sensing insoles (100 Hz, loadsol, Novel) measured the shear force component on the anterior aspect of the shin in the brace condition. Participants wore each brace condition for 7-days and completed daily surveys. RESULTS: Preliminary results demonstrated that the DAO largely outranks the WB for acute comfort (r > 0.5, p < 0.05) and functionality scores (r > 0.5, p < 0.05) across four walking tasks. Peak shear force was greatly reduced in the DAO (r = 0.9, p = 0.002) compared to the WB during overground walking. During 7-day extended wear, comfort scores improved greatly for the DAO compared to the WB (r = 0.5, p = 0.30). CONCLUSION: The improved walking mechanics of the DAO observed in previous studies combined with the current findings of better acute comfort and functionality, and better extended wear comfort suggest that the DAO may be a functional and mechanically superior option for tibial BSI rehabilitation. Table 1: Participant comfort and functionality data from initial assessment and home surveys. - Variable/Walking Task Time (sec) Comfort Functionality DAO WB DAO WB DAO WB Overground Walking (w/o obstacle) 21.7 ± 2.1*‡ 23.7 ± 4.3 7.2 ± 1.8*‡ 5.2 ± 1.7 8.5 ± 1.4*‡ 5.8 ± 1.2 Overground Walking (w/obstacle) 21.9 ± 2.6*‡ 26.0 ± 7.0 7.2 ± 1.9‡ 5.3 ± 2 8.4 ± 1.4*‡ 5.2 ± 1.4 Timed Up-and-Go 17.6 ± 1.6*‡ 20.1 ± 3.6 7.5 ± 1.9*‡ 4.9 ± 2.4 8.4 ± 1.4*‡ 5.3 ± 1.8 Walking Circuit 174.0 ± 12.1*‡ 194.8 ± 27.6 6.9 ± 1.9*‡ 4.5 ± 1.9 7.8 ± 1.4*‡ 4.1 ± 1.8 7-day Extended Brace Wear - - 6.1 ± 2.5‡ 4.8 ± 1.8 - - Comfort scoring guide: 0 = very uncomfortable and 10 = very comfortable.Functionality scoring guide: 0 = unable to perform task, and 10 = normal function.*: significant difference between brace conditions (p < 0.05).Wilcoxon Sign Rank test: §Small effect: r < 0.3, †Medium effect: 0.3 ≤ r < 0.5,‡Large effect: r ≥ 0.5.