Association between forefoot pain and sesamoid rotation angle determined using a weight-bearing plantar ultrasound imaging device.

Forefoot pain is a common symptom for several foot problems. This study aimed to determine whether parameters of forefoot structure (hallux valgus angle (HVA), transverse arch height (TAH) and sesamoid rotation angle (SRA)) are associated with forefoot pain. 547 feet of adult women were divided into two groups: without pain (n = 472) and with pain (n = 75). HVA was measured with a goniometer, TAH and SRA were measured using a weight bearing plantar ultrasound imaging device.Associations between forefoot pain and parameters of forefoot structure were analyzed using the Mann-Whitney U test and univariate and multivariate logistic regression analyses. The intra-rater and inter-rater reliability of the ultrasound images were also tested. SRA was significantly greater in the group with pain compared to the group without pain (p = 0.031) but not HVA (p = 0.057) nor TAH (p = 0.117). The association between forefoot pain and SRA was significant (univariate: p = 0.015 and multivariate p = 0.015), but not between HVA nor TAH. The intra-rater and inter-rater reliability were almost perfect (SRA: ICC1,1 = 0.94, ICC2,1 = 0.91 and TAH: ICC1,1 = 0.88, ICC2,1 = 0.81). We conclude that a higher SRA is related to forefoot pain and should be taken into consideration for assessment of patients with forefoot pain.