Title : Are longer metatarsal lengths ubiquitous in patients with primary metatarsalgia
Abstract:
Background: Metatarsalgia is a generic term used to describe localised forefoot pain around the metatarsals. Primary metatarsalgia is thought to be caused by excessive loading over one or multiple metatarsal heads resulting in inflammation and painful callosities. Maestro et al.in 2003, described an ideal foot morphotype which is currently used to plan for corrective osteotomy in patients with metatarsalgia. The aim of this study is to investigate whether there is a true difference in metatarsal lengths between symptomatic and asymptomatic individuals.
Methods: A retrospective single centre study was carried out between 2019 and 2020. Weightbearing dorsoplantar foot radiographs and patient notes were screened. Patients were grouped into two groups, Group A: Asymptomatic and Group B: Primary metatarsalgia. Exclusion criteria were set to exclude patients with previous foot surgery and secondary causes of metatarsalgia (e.g. Morton’s Neuroma). Metatarsal length differences were measured according to Maestro’s criteria using Carestream. Measurements were taken as: 1st metatarsal - 2nd metatarsal (M1-M2), M2-M3, M3-M4 & M4-M5.
Results: There were 172 patients in Group A and 34 patients in Group B. There was no statistically significant difference across all four metatarsal length differences. This highlights that there is no true overall difference in the metatarsal arcade between the two groups. Twelve patients in group B (35%), underwent Weil’s osteotomy. In this sub-group there was a significant difference in the pre-operative metatarsal length difference between M2-M1 only (p = 0.035) compared to Group A. This was due to a longer 2nd metatarsal (p = 0.039).
Conclusion/Findings: Our results highlight that primary metatarsalgia is an uncommon condition and these patients have a similar metatarsal arcade when compared to the “normal” asymptomatic foot. A subset of patients with primary metatarsalgia have a long 2nd metatarsal which may benefit from Weil’s osteotomy correction.
