Do Arch Supports Alter Foot Alignment in Patients with Metatarsalgia? A Weightbearing CT and x-ray Study

Category: Midfoot/Forefoot; Lesser Toes Introduction/Purpose: Arch-support insoles are frequently included in the treatment plans for common foot ailments including metatarsalgia. Literature has demonstrated that insoles with metatarsal and arch support could relieve walking pain and improve patient-reported measures of function in metatarsalgia. The purpose of this study was to examine alterations in foot alignment among metatarsalgia patients who used arch support insoles. Methods: A clinical trial was initiated after the approval by the institutional review board. Patients with metatarsalgia (age: 18-65 y/o) were included after they consented to participate. Individuals with open wounds, feet asymmetry, using assistive device or brace, and those with BMI more than 35 were excluded. Participants underwent weightbearing computed tomography (WBCT), and weight-bearing x-ray of their feet while standing barefoot or on the insoles (Good Feet™, Dr.’s Own, LLC). The radiological measurements on WBCT and X-rays conducted in these patients are shown in Table 1. The Wilcoxon-Signed Rank test was used for comparison of the continuous measurements, and the interobserver reliability was analyzed with Intraclass Correlation Coefficient (ICC). Results: Ten patients with a mean age of 46.9±13.06 years were included in the study. Observed changes on X-rays include decreased 4th-5th intermetatarsal angle (p=0.04), 2nd-4th/2nd-5th metatarsal tangent angles (p=0.003, p=0.001), and 1st metatarsal length on antroposterior (AP) view (p=0.02). Also, 1st metatarsal declination angle (p=0.002), and talo-first metatarsal angle on AP view (p=0.05) were increased. No significant changes on the WBCT were found, except for a decrease in the first metatarsal pronation angle (p=0.02). Conclusion: Arch support insoles can bring about anatomical changes especially in the forefoot area of patients with metatarsalgia. While the causal correlation between these changes and alleviation of the symptoms cannot be proven based on our data, these outcomes can guide future clinical trials comparing different treatment for metatarsalgia to determine contributing factors to the healing process of this condition.