WHAT IS SESAMOIDITIS?
Sesamoiditis is an inflammation or injury to a sesamoid bone. Whilst this injury can technically occur to any of the sesamoid bones within the human body, it is by far and away most common in the foot, specifically just before the great toe (Lee, Mulder, & Schwartz, 2011).
Sesamoiditis is generally classified as an overuse injury that effects the sesamoid bone and the surrounding tendon tissue. In sport, it is most commonly seen in ballet dancers and other sports that may involve prolonged time on the toes (Lee et al., 2011). It can be also seen in a general population and can occur with increased time in shoes such as high heels or in people with excessive medial foot arches (Sims & Kurup, 2014).
Sesamoid bones are small, almost spherical bones, that are embedded within a tendon or muscle (Goldberg & Nathan, 1987). The name of these bones is derived from a Latin word meaning sesame seed, due to the small size of these bones. The patella, or kneecap, is the largest sesamoid bone in the body. The other common sesamoid bones are present in the hand, foot, wrist and ear. However, the presence of these bones is extremely varied amongst the population, with some being present in almost all humans to others being present in less than 1% (Goldberg & Nathan, 1987). In the foot and hand, sesamoid bones most commonly develop at the distal end of the 1st metacarpal and metatarsal bones, i.e. the base of your thumb and great toe.
X-RAY IMAGE OF A SESAMOID BONE IN THE FIRST METATARSAL
Sesamoid bones within the musculoskeletal system can play an important role in force transmission. They act as fulcrums to increase the mechanical advantage of the tendon (Goldberg & Nathan, 1987). Sesamoid bones at the base of the great toe also play an important weight bearing role as they distribute load from the first metatarsal. There are usually two sesamoid bones at the base of the great toe, the medial sesamoid bone is referred to as the tibial sesamoid, whereas the lateral sesamoid bone is referred to as the fibular sesamoid (Goldberg & Nathan, 1987). When an individual rises onto their toes, these sesamoid bones take the main weight-bearing force for the medial foot (Sims & Kurup, 2014). The blood supply to these bones is tenuous and variable amongst the population, potentially leading to delayed or unsuccessful healing following injury.
WHAT ARE THE SIGNS AND SYMPTOMS OF SESAMOIDITIS?
The most common symptom of sesamoiditis is localised pain to the under surface of the foot at the base of the great toe. Sesamoiditis more commonly effects the tibial sesamoid than the fibular sesamoid (Sims & Kurup, 2014). It usually occurs during exercise that involves running, jumping or being on your toes for long periods. Pain is also usually noted when pushing off or taking off in activities such as walking and running. Pain often worsens as the aggravating activity continues and in cases will last for periods after the activity ceases.
People with sesamoiditis can often adopt an abnormal gait pattern that involves weight-bearing on the outside of the foot to reduce weight-bearing over the first toe.
DO I HAVE SESAMOIDITIS?
A diagnosis of sesamoiditis is based on clinical findings and in some cases can be a diagnosis of exclusion (Sims & Kurup, 2014). Clinical examination involves:
- Detecting the location of pain and how isolated the symptoms present
- Pain on extension of the great toe
- Passive axial compression test (Allen & Casillas, 2001)
- Passive plantarflexion of the metatarsophalangeal joint
- Observation of aggravating tasks such as walking or running
- Taping to modify load distribution and test for easing of symptoms
The passive axial compression test involves maximal dorsiflexion of the great toe and then applying a compressive force proximal to the sesamoid bones; a positive test is considered with reproduction of symptoms (Allen & Casillas, 2001). It should be noted there is limited research for this test and as such it’s validity has not been well examined.
In some cases, sesamoiditis can occur suddenly, even though the pathology may have been present without symptoms for a long period of time. In these instances, ruling out specific injuries such as a fracture of the sesamoid bone using imaging is important.
Whilst imaging techniques, such as MRI, may be helpful, they’re often used to exclude other possible diagnosis.
TREATMENT OF SESAMOIDITIS
Sesamoiditis is often managed conservatively, certainly as a first line of treatment. The research evidence is supportive of conservative management involving (Robertson, Goffin, & Wood, 2017):
- Activity cessation or modification
- Non-steroidal anti-inflammatory medication
- Shoe modification to involve stiffer soled shoes to limit dorsiflexion of the great toe
- Full foot orthoses
- A J shaped pad to avoid excessive weight-bearing load through the sesamoid bone
In most cases people with sesamoiditis will return to their pre-injury level of activity, though the time for return can vary amongst individuals. If conservative management is unsuccessful, surgical intervention has demonstrated to be successful in allowing people to return to activity. Surgical procedures can involve a full or partial sesamoidectomy or internal fixation of the sesamoid bone (Robertson et al., 2017).
Whilst fracture can be a possible diagnosis, often the mechanism for injury is sudden, unlike that of sesamoiditis. Other possible diagnoses for overuse pattern injuries to this area include (Sims & Kurup, 2014):
- Stress reaction or fracture of the sesamoid bone
- Bursitis of the intermetatarsal or adventitial bursae
- Compression of the plantar medial and plantar lateral digital nerves
- Infection of the sesamoid bone
- Avascular necrosis of the sesamoid bone
- Intractable plantar keratosis
As abovementioned, sesamoiditis is often a diagnosis of exclusion whereby imaging can assist in ruling out some of the above listed pathologies.
Allen, M. A., & Casillas, M. M. (2001). The Passive Axial Compression (PAC) Test: A New Adjunctive Provocative Maneuver for the Clinical Diagnosis of Hallucal Sesamoiditis. Foot & Ankle International, 22(4), 345-346.
Goldberg, I., & Nathan, H. (1987). Anatomy and pathology of the sesamoidbones. International Orthopaedics, 11, 141-147.
Lee, D. K., Mulder, G. D., & Schwartz, A. K. (2011). Hallux, sesamoid, and first metatarsal injuries. Clin Podiatr Med Surg, 28(1), 43-56. doi:10.1016/j.cpm.2010.09.002
Robertson, G. A. J., Goffin, J. S., & Wood, A. M. (2017). Return to sport following stress fractures of the great toe sesamoids: a systematic review. Br Med Bull, 122(1), 135-149. doi:10.1093/bmb/ldx010
Sims, A. L., & Kurup, H. V. (2014). Painful sesamoid of the great toe. World J Orthop, 5(2), 146-150. doi:10.5312/wjo.v5.i2.146