Anterior-posterior x-ray of the left foot of a competitive dancer who has been treated for sesamoiditis.
Lateral x-ray of the patient’s foot.
X-ray taken in axial sesamoid view.
A competitive dancer, aged 18 years, presents with several months of pain in her left foot. She has been seen in the past by her primary care provider and a podiatrist, who have treated her for sesamoiditis. She has tried a period of non-weight-bearing activity, nonsteroidal anti-inflammatory drugs, custom orthotics, and physical therapy, but the pain persists when she dances. On examination, the patient has focal tenderness over the medial sesamoid of the left great toe. X-rays, including one with a sesamoid view, were taken.
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Sesamoids are bones that are embedded within a tendon or muscle. They act as pulleys to help increase the ability of the tendons to transmit muscle forces. Sesamoids can be found in many areas of the body, with the patella being the largest.
The 2 sesamoids of the great toe include the medial (tibial) and the lateral (fibular) sesamoids. These 2 hallucal sesamoids are located within the flexor hallucis brevis tendon beneath the first metatarsal head. They function to absorb weight-bearing pressure beneath the first metatarsal head, to protect the flexor hallucis longus as the tendon glides between the sesamoids and to aid in the pulley mechanism to increase metatarsophalangeal flexion that elevates the metatarsal head off the ground.
Several conditions can affect the hallucal sesamoids, including fracture (both stress and acute), dislocation, inflammation known as sesamoiditis, chondromalacia, sprain (turf toe), flexor hallucis brevis tendinitis, and osteochondritis dissecans.
Sesamoiditis should be a diagnosis of exclusion when other causes of pain have been ruled out. Sesamoiditis occurs commonly in those who participate in high-impact activities such as ballet dancing and running. The most common mechanism of injury is repetitive forceful dorsiflexion of the first metatarsophalangeal joint. On physical examination, focal tenderness of the involved sesamoid should be present. The focal tender spot will move with the sesamoid as the great toe is extended and flexed.
The tibial (medial) sesamoid is the largest and most likely to be injured, as it distributes more weight than the fibular (lateral) sesamoid. Pes cavus or high arches cause increased weight bearing over the great toe and can precipitate sesamoiditis.
Common x-rays ordered to evaluate the sesamoids include anterior-posterior, lateral, and axial sesamoid view, as in this case. X-rays look for bipartite sesamoid, osteochondritis dissecans, or fracture. Bipartite sesamoid is found in 25% of the population, with 70% occurring bilaterally. Magnetic resonance imaging (MRI) is useful to evaluate for bone marrow edema, stress fracture, and surrounding soft tissue pathology. MRI is particularly useful to differentiate bipartite sesamoid from acute fracture.
Initial treatment involves reducing weight bearing across the big toe and administering nonsteroidal anti-inflammatory drugs. The patient can be placed in a rigid-sole shoe or walking boot to avoid excessive dorsiflexion of the great toe. Custom orthotics or foot pads can be used to reduce weight-bearing forces on the metatarsal head, and iontophoresis can help reduce inflammation locally. Steroid injections are not recommended because of the risk for tendon rupture and difficulty of accurate placement.
Conservative treatment is successful in most patients. However, patients whose symptoms persist for more than 9 months despite conservative treatment should consider sesamoidectomy. The tibial (medial) sesamoid alone is commonly excised because it is the frequent pain generator. Bilateral sesamoidectomy should be avoided, as it results in a high incidence of postoperative cock-up deformity of the great toe. Sesamoid fractures should be treated in a weight-bearing boot or cast for 6 weeks. The fracture can take months to heal and can often end in eventual sesamoidectomy to relieve pain.
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).
- Sims AL, Kurup HV. Painful sesamoid of the great toe. World J Orthop. 2014;5(2):146-150.
- Wheeless CR III. Sesamoid bones of the feet. In: Wheeless CR III, Nunley JA II, Urbaniak JR. Wheeless’ Textbook of Orthopaedics. http://www.wheelessonline.com/ortho/sesamoid_bones_of_the_foot. Accessed December 21, 2015.