IMPACT OF BIG TOE AMPUTATION ON FOOT BIOMECHANICS

Background: The big toe plays an important role in foot biomechanics. During walking, it poses twice the total pressure of the other four toes. It has a significant contribution in windlass mechanism needed for push off; its amputation will change intensely in foot biomechanics. Aim: Comparing the peak-pressures and pressure-time-integral on the foot with unilateral amputations of the big toe with preservation of the 1st metatarsal, with the patients' contralateral-intact-foot. Subjects and methods: Ten diabetic patients with unilateral amputations of the big toe of at least 4-years duration were evaluated with the in-shoe-pressure-measurement-systemª in their diabetic footwear and plate-formb while they walk bare feet. We compared peak-pressures and pressure-time-integral under all metatarsals, lesser toes, mid-foot and heel in unilateral amputations of the big toe and contralateral-intact-foot using Wilcoxon's-matched-pairs signed-rank test. Results: Using in-shoe-pressure-measurement-systemª, peak-pressures and pressure-time-integral were significantly higher under 1st metatarsal-head, lesser toes in the unilateral amputations of the big toe compared with contralateral-intact-foot, and non-significant changes were found under the lesser metatarsals and midfoot. Heel showed higher pressure on the contralateral-intact-foot, but the results were statistically insignificant. While using plate-formb, peak-pressures and pressure-time-integral were significantly higher under 1st metatarsal-head, 3rd, 4th and 5th toes in the unilateral amputations of the big toe compared with contralateral-intact-foot with non-significant changes over other regions. Conclusion: Big toe amputation significantly altered pressure distribution of the foot with increased foot pressure in forefoot area that contributes to an increased risk of re-ulceration and re-amputation that necessitate in shoe intervention with custom made insoles.