When a patient comes to see me with pain in the ball of their foot that is aggravated by activity, they can usually point right to where the pain is. The pain is often directly beneath one or both of the sesamoids that sit anatomically under the great toe joint (1st metatarsophalangeal joint).

These tiny pea-shaped bones help with weight bearing and elevate the big toe bone. When tendons that attach to these bones become irritated they can cause inflammation and pain.

Causes

Sesamoiditis is one of several conditions that cause pain under the big toe joint (Metatarsalgia). It’s more common in certain types of athletes and dancers who put a lot of stress on their feet as well as people with particular foot types that display rigidity and pronounced anatomy in the area of the sesamoids. Sesamoiditis is caused by chronic straining of the tendons associated with two little pea-shaped bones called sesamoids located on the underside of the ball of your foot. These bones act as a pivot for the tendons that bend your big toe.

Sesamoids are unique in the body because they don’t articulate with any other bone, but rather lie under tendons or surrounded by muscle. They provide a surface for tendons to glide over, increasing the tendons’ ability to move muscles and bear weight. In addition to providing a smooth surface for tendons to glide over, sesamoids also serve as a weight bearing structure for the ball of your foot.

Sesamoiditis is primarily a repetitive stress injury and most cases of it can be effectively treated conservatively. Rest, activity modification, and appropriate shoe gear can all reduce the load on your sesamoids. Medications and steroid injections can also be used to help reduce pain and inflammation. Surgery is only recommended if nonsurgical treatments don’t improve symptoms or there is evidence of severe bone damage like fractures.

Symptoms

The pain from sesamoiditis typically develops gradually. You might feel a dull ache under the big toe that gets sharper during activity or when you put pressure on the foot. The pain may also be more noticeable when you wear certain shoes, especially high heels.

Your doctor will examine your foot and the area around your big toe for signs of tenderness and swelling. They might gently bend and move your big toe joint in ways that replicate how your feet move when you walk (passive axial compression test). They might also take X-rays of the ball of your foot and your big toe. These X-rays can help your doctor see whether there is a sesamoid bone fracture or other injuries.

Your doctor might recommend resting your foot, icing it frequently and wearing soft-soled, low-heeled shoes or clogs. They might suggest using a cushioning pad made of dense foam rubber to reduce the load on your sesamoids. They might also suggest calf stretches and exercises to strengthen your toe flexors and arches. If your symptoms don’t improve with conservative treatments, your doctor might recommend surgery to remove part or all of the sesamoids. This is usually only recommended if there’s a severe fracture or other damage to the foot. If you don’t get treatment, chronic pain or permanent damage to your toe joints might occur.

Diagnosis

You’re a runner, dancer, or athlete who loves what you do but pain in the ball of your foot stops you from doing it. Suddenly, your morning run or basketball game feels like walking on sharp pebbles in the ball of your foot.

You might have a condition called sesamoiditis. It’s an overuse injury involving the inflammation of tendons attached to two tiny, pea-shaped bones in your foot called sesamoids. The little bones are embedded in tendons under the big toe joint and act like pulleys to help your foot move better.

During an examination, your podiatrist will look for tenderness at the site of the sesamoids. He or she may also manipulate the bone slightly or ask you to bend and straighten your large toe to see if there’s an intensification of the pain. X-rays might be needed to check for a fracture and to see the extent of the inflammation.

Your podiatrist will likely recommend that you reduce your activity level and use shoes with good arch support and wide toe boxes. You might also get a custom orthotic to address flat feet or an inward rolling motion (overpronation) that can put extra stress on the ball of your foot. You might also take anti-inflammatory medications to control the pain. Sesamoiditis usually gets better on its own, but it can take months to recover from.

Treatment

Symptoms of sesamoiditis can be relieved with conservative treatments that include rest, ice packs, over-the-counter pain relievers, and physical therapy. In severe cases, advanced medical treatment is necessary.

A podiatrist can help diagnose the condition by asking about symptoms and performing a visual examination of your foot. They will also move your big toe joint to see if the movement causes pain. They may recommend x-rays or an MRI to rule out a fracture or other damage to the tissues.

Sesamoiditis is most common among people who participate in high-impact activities such as running, basketball, tennis, and dance. It’s also more likely to affect people with certain foot structures, including high arches, flat feet, and a natural foot alignment that bends the big toe toward the ground (overpronation).

Your footwear can make or break your chances of developing sesamoiditis. Shoes with thin soles and narrow toe boxes place more pressure on the small bones beneath your big toe joint. Switching to a shoe with a stiffer sole and rocker bottom helps shift pressure away from the painful areas. Adding a pad of dense foam rubber under the big toe is another way to cushion the area.

If you are diagnosed with sesamoiditis, avoid activities that put repeated stress on your big toe joint. Start slow when you return to activity, and don’t push yourself too hard. Mild cases of the condition often improve within a few weeks with proper offloading and rest.