An interesting case: Sesamoid Fracture

I diagnosed a sesamoid fracture in a young woman this week. The presenting complaint, on Wednesday, was of “pain in the ball of the foot under the big toe joint for nearly 9 months, but 3 days ago (Sunday), whilst doing a long day shift the pain got really bad and only stops when I take weight off the foot.”

The ball of the foot was noticeably swollen, but not inflamed. However, when I applied light finger pressure to the area the pain increased and was particularly bad at one spot. The lady has a high-arched foot (pes cavus), but it is flexible not rigid. She is not overweight, but is very active everyday of the week -including some weekends – working long hours. She told me that she usually wears a low heeled shoe or sandal, but it had become impossible to wear slip-ons or ‘push-ins’ because of the pain. The only relief was to wear trainers with a thick sole. When the weight was removed by sitting or resting in bed there was no pain.

By applying a protective pad to the sole and the arch, with a cut-out around the painful area, painfree walking was possible. An X-ray was requested; both feet for reasons that I’ll explain shortly and a follow-up appointment was arranged for Thursday morning.

We met on Thursday and the X-ray showed a clear break in the lateral sesamoid. The pain was also worse because the padding had slipped backwards and out of position. By repositioning the pad, the pain was relieved again. I instructed her to use trainers as often as possible and suggested that she do the replacement padding herself. In addition I arranged for her to be fitted with an Aircast below knee walker, which she could borrow from the practice on Friday after work.

The treatment for this condition is mainly patience and removal of pressure. Which is why I decided on the Aircast. When we fitted the Aircast walking was immediately painfree. Now we both have to wait for the bone to fuse as one or even two bones.

There are two sesamoids under the ball of each foot. They allow a particular muscle to pull the foot down during standing and walking; they also survive a lifetime of bending at the ball (the first metatarso-phalangeal joint). In some people, one of the sesamoids is naturally bifurcate and can look as if it is fractured – called a normal variant -that is why I asked for both feet to be X-rayed. This fracture may heal in two parts also, which won’t be a problem.

Pain in this part of the foot is quite common. It is caused by excessive amount of shearing, compression or tensile stress over the joint. It can be associated with sports like golf and tennis. Starting running or training and doing too much or running in old trainers. Wearing old worn shoes, where the inner sole gets a deep imprint. It can be associated with rheumatoid athritis, or even standing on a ladder for long periods, when you aren’t used to doing that! Nearly always it affects people with a high arched foot who have over-used their feet.

Initially the bone and the joint under them become inflamed and that is called sesamoiditis. Ignore this and a sesamoid fracture may result.