Sesamoiditis

What is it?

The sesamoid bones are two spherical shaped bones that sit under the head of the 1st metatarsal bone whose function is to aid the mechanical action of the tendons. The inflammation of the sesamoid bones and surrounding tissues is known to be sesamoiditis. This often causes intense pain, where it can be directly felt below the metatarsal joint in the big toe.

Causes

• Over pronation; excessive rolling in of the foot
• Forefoot valgus or plantar flexed first ray. In layman’s terms this means that the sesamoid bones sit lower than the rest of the forefoot. This causes increased ground pressure under the bones with an increased chance  of injury
• People with high arches, whereby they place a greater strain on the forefoot
• Age – arthritic changes to the sesamoid bones, this is where the articulation with the first metatarsal bone is displaced
• Osteoarthritis a likely cause in older patients

Signs and Symptoms

Pain is generally experienced while walking. However any weight bearing exercise is likely to exacerbate the symptoms. The pain is greatest during “toe off” when walking, this is especially due to the fact that the body weight transfers onto the toes.

Sesamoiditis does not solely affect the bones, but includes tenderness of the surrounding tissues. This intensifies when direct pressure is inflicted onto the area. When the weight is taken off, the pain usually rapidly subsides. Pain experienced may persist for longer periods as the condition deteriorates. The most commonly sign for this condition is a small degree of swelling under the first metatarsal joint.

Treatment

• Foot orthoses to correct the biomechanical imbalance and reduce loading to the first ray. Good supportive footwear is also necessary. For best result conservative treatment is best to intervene in the earlier stages.
• Non-steroidal anti-inflammatory medications.
• Surgery in severe cases.