Does forefoot width influence the development of Morton’s Neuroma?
The exact cause of Morton’s neuroma is still unclear. It has been suggested that Morton’s neuroma represents an entrapment neuropathy in the tunnel formed by the Deep Transverse Metatarsal Ligament and the two metatarsals, and that during both the mid- stance and heel-off stages of walking, the interdigital nerve is pulled and compressed by the ligament.
Wearing narrow shoes is believed to be a common risk factor for developing Morton’s neuroma. Tight footwear can cause compression of an interdigital nerve below the deep transverse metatarsal ligament or pinching of an interdigital nerve by the two neighboring metatarsal heads, leading to the development of Morton’s neuroma.
Regardless of shoes, is it possible that the width of the forefoot may induce a similar susceptibility to Morton’s neuroma? (A narrow forefoot may correspond to narrow intermetatarsal space, potentially leading to nerve compression or pinching?)
A recent study evaluated 84 patients (67 women and 17 men, aged 22 to 71 years) with Morton’s neuroma and no other conditions affecting the structure of the forefoot. An XRay analysis of the foot was performed and the intermetatarsal distances, the intermetatarsal angle, and the size of the neuroma were measured.
No significant differences were found between the forefoot width, the intermetatarsal angle and the intermetatarsal distance of the involved web space in the affected and unaffected feet of the patients, nor between patients and the controls. The size of the neuroma was also found to be unrelated to these radiographic parameters. Patients with a neuroma did not have a narrower forefoot.
The authors concluded that the structure and width of the forefoot, which can induce pinching of an interdigital nerve, may not be the main cause of Morton’s neuroma nor a factor that significantly influences the size of the neuroma. It is hypothesized that pressure in the surrounding soft tissues during walking may play a more relevant role in the development of Morton’s neuroma.
Park YH, et al (2017). The role of the width of the forefoot in the development of Morton’s neuroma. Bone Joint J, 99-B(3):365-368. doi: 10.1302/0301-620X.99B3.BJJ-2016-0661.R1