The sesamoid bones are two very small bones under the big toe joint. They kind of function like two mini knee caps which help the tendons be better levers to move the joint:
Sesamoiditis is a painful inflammation of the structures around the sesamoid bones. The location of these two bones make them particularly prone to being overloaded.
Symptoms of sesamoiditis
The symptoms of a sesamoiditis is a gradual onset of pain under the big toe joint, that is worse when standing on the foot, especially on a hard surface. On palpation of the area, there is usually quite a bit of pain if you push hard. Conditions like gout and osteoarthritis can also cause pain in the joint, but that pain is more inside the joint rather than pushing on those small sesamoid bones under the joint.
Cause of sesamoiditis
The cause of sesamoiditis is almost always an overuse type of injury combined with a lack of fatty padding under the joint (fat pad atrophy). For example, this might come from standing all day at work or playing a lot of sport. Sports like tennis, which put a lot of pressure on this area because you pivot on this joint when playing tennis or similar sports.
Treatment of sesamoiditis
The treatment of sesamoiditis will depend on how painful it is. If it is very mild, then all that may be needed is a pair of shoes that have a lot of padding under the ball of the foot or a cushioning insole in the shoe. That extra padding maybe all that is needed.
A common approach to dealing with sesamoiditis is to use something like podiatry felt to get pressure or force off the painful area. Some call these ‘dancer’s pads’. The felt comes in sheets and can be cut down to size to accommodate the painful area over the sesamoid bones. The felt padding can be used straight on the foot or adhered to an insole that goes in the shoes:
Using padding on the foot is best in the short term or if the sesamoiditis symptoms are really painful. With a pad on the foot, you get the offloading 24/7, so even when barefoot. This is not necessarily a good approach over the long term. In the long term, you can use felt padding on the insole in the shoe, especially in sports shoes. It is reasonably easy to map out the painful area on the insole and cut some of the self-adhesive podiatry felt to off-load pressure and force from that painful area:
If you need an insole for your shoes for the padding, we have these arch supports which should work well. The front part can be used to stick the felt on and the arch support will help spread the weight out over the whole foot, reducing it on the area where the sesamoid bones are.
If these measure do not help, then see a podiatrist who may need to fashion custom made foot orthotics to achieve the off-loading more efficiently. Sometimes injection therapy is needed to settle the inflammation around the sesamoid bones. In a few of the worst cases, surgery may be needed to deal with the sesamoiditis.