Sesamoiditis

1. Defenition / Description

30 % of the stress fractures that involve the sesamoid is sesamoiditis. Sesamoïditis is a painfull inflammation of the sesamoïd bones. This disorder is most commonly diagnosed with the hallux, but also the sesamoid bones off the pollex and the index finger can be involved. The last one isn’t common. (1)

The symptoms of sesamoïditis can heal very fast. It only takes a few weeks.

2. Clinicaly Relevant Anatomy

The sesamoïd bones are separated by a bony ridge called the crista, the plantair aspect off the first metatarsal head. Even though, they do are connected to one another by an intersesamoïd ligament. This whole structure is surrounded by the flexor hallucis brevis tendon, a specialized subcutaneous layer and skin. (3)

3. Epidemiology / Etiology

Pathologic conditions involving the sesamoïd are rare and usually of a posttraumatic or degenerative etiology. (1) Sesamoïditis is a chronic injury, caused by frequent pressure and results in irritation and inflammation of the surrounding tissues. There are different causes of sesamoïditis, for instance damage to the sesamoïd bones,  a deformation of the metatarsophalangeal joint or gout.

Other factors that have a negative influence on the development of sesamoïditis are:

•  Osteoartritis;
• osteoporosis;
• walking on high heels;
• the size of the sesamoids (the bigger, the higher the risk);
• the practiced sport (volleyball, running, gymnastics,..).
  

4. Clinical Presentation

In case of sesamoïditis, there are no bruises or rednesses visible, but this disorder is associated with local pain and swelling, which results in problems whit the movement of thehallux . This pain can be a dull aching type or a sharp throbbing type. This causes a limitation of the dorsiflexion and the plantarflexion of the first metatarsofalangeale joint.

The pain begins as a mild pain that gradually gets worse when the strained activity is continued. In the case of sesamoïditis of the hallux, is the pain located in the ball of the foot, especially on the medial side. The sesamoïd bones are also very sensitive. The location of the tenderness corresponded exactly to the location of the medial sesamoid bones.

The problem may be situated in both sesamoïds, although the medial one is involving more frequently. (2)

  5. Diagnostic Procedures

The diagnosis of sesamoïditis should be based on the symptoms. These are inflammation and swelling, located at the inferomedial aspect of ball of the hallux. (1,2) This causes painful movement of the hallux. However clinical reproduction of the intensity of the symptoms are not always successful, which may contribute to an inconclusive diagnosis. (3) The problem is that sesamoiditis may be associated with bursitis, tendinosis, and tenosynovitis. (5)

To complete the diagnosis the use of several imaging methods are recommended :

• X-ray;
• MRI;

 CT-scan;
 bone scan. 
When a stress fracture is suspected, a bone scan or a CT-scan are seen as more reliable in confirming the diagnosis than X-ray and MRI. (5)
The second method to support the diagnosis of sesamoïditis, is the use of the passive axial compression test (PAC) (3). This maneuver should be specific for the sesamoids as all other soft tissues about the plantar aspect of the first metatarsophalangeal joint are in a relaxed position. This test is helpful for the physiotherapist to perform his diagnosis of sesamoïditis.