Sesamoiditis is a condition that affects the sesamoid bones, which sit under the first metatarsal head to protect the flexor tendons that run to the toe.

This is an uncommon condition and it generally only affects people with high arches and manifests as a pain on the bottom of the ball of the foot.

Inflammation in the sesamoid bones, either the medial (tibial) or the lateral (fibula) sesamoids, can be extremely painful and can halt all activity.

What causes sesamoiditis

High arched feet, particularly the stiffer type, are poor shock absorbers. The condition will occur more often as a result of a combination of factors – high arched feet with a short achilles tendon or tight calf muscles.

The compensation for the tight calves leads to an increase of pressure on the ball of the foot in the high arched foot. And because high arched feet generally do not pronate too much, the ball of the foot comes under a lot of pressure, leading to irritation of the sesamoids.

There will often be other signs like callus formation, or blistering in sportsmen on the ball of the foot.

Treatment for sesamoiditis

  • Treatment will involve rigorous stretching exercises, heel raises, and orthotics for those where it occurs through excessive pronation.
  • Soft tissue mobilisation can help with calf flexibility, foot mobility and improve ankle range of motion and reduce fore-foot stress.