Plantar forefoot pain: ultrasound findings before and after treatment with custom-made foot orthoses

PURPOSE: No prior studies investigated the role of ultrasound in the assessment of response of patients undergoing treatment of metatarsalgia with custom-made orthoses. Our aim was to describe ultrasound findings of patients with plantar forefoot pain treated with custom-made foot orthoses. METHODS: Twenty patients (15 females; mean age: 62.6 ± 11 years) affected by metatarsalgia in 27/40 feet underwent clinical evaluation before, three months and six months after treatment with custom-made full foot insole with a support proximal and an excavation below the painful metatarsals. Ultrasound was performed before and three months after the use of orthoses to examine the presence of intermetatarsal/submetatarsal bursitis, metatarsophalangeal joints effusion, anterior plantar fat pad oedema, flexor tendinitis/tenosynovitis, and Morton’s neuroma. Outcome measures were clinical response with Foot Function Index (FFI)/Visual Analogue Scale (VAS) and ultrasound features changes. RESULTS: Median VAS and FFI before treatment were 8[5–8.5] and 45.85[32.4–59.4], respectively. After 3 and 6 months of insoles use, both median VAS (2.5 [0–5] and 0 [0–2.75], respectively) and median FFI (7.9 [3.95–20] and 0 [0–3.95], respectively) showed a significant reduction in pain and disability (p < .001). Before treatment, ultrasound revealed 22 intermetatarsal bursitis, 16 submetatarsal bursitis, 10 joint effusions, 20 fat pad oedema, 3 flexor tendinitis/tenosynovitis and 3 Morton’s neuromas. After 3 months of treatment, a significant decrease of intermetatarsal bursitis (7, p < .001) was observed. No significant changes were observed in any other ultrasound parameters. CONCLUSION: Ultrasound might be able to detect some imaging features associated with the response of forefoot pain to custom-made foot orthoses, especially intermetatarsal bursitis.