Sesamoiditis is a common cause of metatarsalgia Metatarsalgia Metatarsalgia is a general term for pain in the area of the metatarsophalangeal joints. (See also Overview of Foot and Ankle Disorders.) Most common causes include Freiberg disease Metatarsal... read more . The 2 semilunar-shaped sesamoid bones are located within the flexor hallucis brevis tendon and aid the foot in locomotion. The medial bone is the tibial sesamoid, and the lateral bone is the fibular sesamoid. Direct trauma or positional change of the sesamoids due to alterations in foot structure (eg, lateral displacement of a sesamoid due to lateral deviation of the great toe) can make the sesamoids painful. Sesamoiditis is particularly common among dancers, joggers, and people who have high-arched feet or wear high heels. Many people with bunions Bunion Bunion is a prominence of the medial portion of the head of the first metatarsal bone. The cause is often variations in position of the first metatarsal bone or great toe, such as lateral angulation... read more have tibial sesamoiditis. This can sometimes be confused clinically with gout.
(See also Overview of Foot and Ankle Disorders Overview of Foot and Ankle Disorders Most foot problems result from anatomic disorders or abnormal function of articular or extra-articular structures (see figure ). Less commonly, foot problems reflect a systemic disorder (see... read more .)
Bones of the Foot
Symptoms and Signs of Sesamoiditis
The pain of sesamoiditis is beneath the head of the first metatarsal; the pain is usually made worse by ambulation and may be worse when wearing flexible thin-soled or high-heeled shoes. Occasionally, inflammation occurs, causing mild warmth and swelling or occasionally redness that may extend medially and appear to involve the first metatarsophalangeal joint. Sesamoid fracture can also cause pain, moderate swelling, and possibly inflammation.
Diagnosis of Sesamoiditis
Arthrocentesis if there is circumferential joint swelling
Imaging if fracture, osteoarthritis, or displacement is suspected
With the foot and first (great) toe dorsiflexed, the examiner inspects the metatarsal head and palpates each sesamoid. Tenderness is localized to a sesamoid, usually the tibial sesamoid. Hyperkeratotic tissue may indicate that a wart or discrete callus is causing pain.
If inflammation causes circumferential swelling around the first metatarsophalangeal joint, arthrocentesis is usually indicated to exclude gout Gout Gout is a disorder caused by hyperuricemia (serum urate > 6.8 mg/dL [> 0.4 mmol/L]) that results in the precipitation of monosodium urate crystals in and around joints, most often causing recurrent... read more and infectious arthritis Acute Infectious Arthritis Acute infectious (septic) arthritis is a joint infection that evolves over hours or days. The infection resides in synovial or periarticular tissues and is usually bacterial—in younger adults... read more .
If fracture, osteoarthritis, or displacement is suspected, x-rays are taken. Sesamoids separated by cartilage or fibrous tissue (bipartite sesamoids) may appear fractured on radiographs. If radiographs are equivocal, MRI is indicated for diagnosis.
Treatment of Sesamoiditis
New shoes, orthotics, or both
In patients with sesamoiditis, simply not wearing the shoes that cause pain may be sufficient. If symptoms of sesamoiditis persist, offloading pads as well as shoes with a thick sole and orthotics are prescribed and help by reducing sesamoid pressure. If fracture without displacement is present, conservative therapy may be sufficient and may also involve immobilization of the joint with the use of a flat, rigid, surgical shoe.
Nonsteroidal anti-inflammatory drugs (NSAIDs) and injections of a corticosteroid/local anesthetic solution can be helpful (see Considerations for Using Corticosteroid Injections Considerations for Using Corticosteroid Injections Most foot problems result from anatomic disorders or abnormal function of articular or extra-articular structures (see figure ). Less commonly, foot problems reflect a systemic disorder (see... read more ). Although surgical removal of the sesamoid may help in recalcitrant cases, it is controversial because of the potential for disturbing biomechanics and mobility of the foot. If inflammation is present, treatment includes conservative measures plus local infiltration of a corticosteroid/anesthetic solution to help reduce symptoms.
Dancers, joggers, and people who have high-arched feet, wear high heels, or have bunions can develop pain at the sesamoids beneath the head of the first metatarsal.
Pain is worse when weight-bearing, particularly when wearing certain shoes.
Diagnose based on clinical findings; exclude infection and gout with synovial fluid analysis when swelling is present and exclude suspected fracture with radiographs and sometimes MRI.
Prescribe new, thick-soled shoes, offloading pads, and orthotics that decrease pressure on the sesamoids, or both.