Sesamoiditis

Introduction

Sesamoiditis is a painful inflammation of sesamoid bones. Sesamoid derived from Latin "Sesamum", meaning "sesame seeds" (due to small size of sesamoid bones).

Clinically Relevant Anatomy

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

Epidemiology / Etiology

Pathological conditions involving the sesamoid are rare and usually of post-traumatic or degenerative etiology.⁽¹⁾ Sesamoiditis is a chronic injury, caused by frequent pressure and results in irritation and inflammation of the surrounding tissues. There are different causes of sesamoiditis, for instance damage to the sesamoid bones, a deformation of the meta-tarso phalangeal joint or gout.

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

•  Osteoartritis;
• Osteoporosis;
• Walking on high heels;
• The size of the sesamoids (the bigger, the higher the risk);
• High impact sport (volleyball, running, gymnastics,..).
  

Clinical Presentation

In case of sesamoiditis, there are no bruises or redness visible, but this disorder is associated with local pain and swelling, which results in problems with the movement of the hallux . This pain can be a dull aching type or a sharp throbbing type. This causes a limitation in the dorsi-flexion and the plantar-flexion of the first meta-tarso phalangeal joint.

The pain begins mildly that gradually worsen when the strained activity is continued. In the case of sesamoiditis of the hallux, the pain is located in the ball of the foot, especially on the medial side. The sesamoid 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 sesamoids, although the medial one is more frequently involved. ⁽²⁾

Diagnostic Procedures

The diagnosis of sesamoiditis should be based on the symptoms. These are inflammation and swelling, located at the infero-medial 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.

Outcome Measures

As mentioned in the diagnostic procedures the passive axial compression test (PAC) can be used as an outcome measure.⁽³⁾ Also imaging methods, such as a bone scan and ST-scan are reliable outcome measures.

For postoperative outcome measurements several instruments may be used ⁽⁶⁾ :

• The Short Form-36 (SF-36);
• foot Function Index  disability scale (FFI);
• visual analog scale (VAS).

Medical Management ⁽²⁾

The initial management for sesamoïditis is conservative. This includes rest in combination with ice and the use of padded  insoles to reduce pressure on the affected zone. The patient should take NSAID’s  to reduce the swelling or should receive local corticosteroids injections in the metatarsophalangeal joint.

To be sure of a fast recovery, the hallux may additionally be bound with tape to immobilize the joint as much as possible. Specific therapy for gout has to be given if this appears to be the cause.

Usually the treatment of sesamoïditis is noninvasive, but a sesamoidectomy is recommended when the conservative therapy fails.

Physical Therapy Management

For the physical treatment of sesamoïditis we have to make the difference between non-surgical rehabilitation and post-surgical rehabilitation.

As mentioned earlier, the physiotherapist will recommend wearing soft shock absorbing soles that help away pressure on the sesamoïds. During non-surgical rehabilitation, the physiotherapist applies treatments to the painful area to help control pain and swelling. These treatments involve the use of ultrasound, moist heat and soft-tissue massage. Sometimes the treatment also includes iontophoresis.

The treatment after a surgery begins with wearing a cast for up to four weeks. During that period, absolute rest is recommended. After four weeks the patient wears a short walking cast for another two months. Afterwards active exercises can be started.

Differential diagnosis

Damage to the sesamoids, such as fragmentation, may result into inflammation. Therefore, sesamoiditis can mimic tenosynovitis and to optimize the patient’s care, the clinician should be aware of this. Also bursitis and tendinosis have similar symptoms. ⁽¹⁾

References

1. Lang CJ, Lourie GM. Sesamoiditis of the index finger presenting as acute suppurative flexor tenosynovitis. J Hand Surg 1999; 24A : 1327-1330. (Level of evidence : 4)

2. Wakhlu, A. An uncommon cause of great toe pain: sesamoiditis. Journal of Indian Rheumatology Association 2004; 12(3) : 130-132. (Level of evidence : 4)

3. Allen MA, Casillas MM. The passive axial compression (PAC) test: a new adjunctive provocative maneuver for the clinical diagnosis of hallucal sesamoiditis. Foot Ankle Int 2001; 22(4) : 345-346. (Level of evidence : 2C)

4. Saxena A, Krisdakumtorn T. Return to activity after sesamoidectomy in athletically active individuals. Foot Ankle Int 2003; 24(5) : 415-419. (Level of evidence : 2B)

5. Biedert R, Hintermann. Stress fractures of the medial great toe sesamoids in athletes. Foot Ankle Int 2003; 24(2) : 137-141. (Level of evidence : 2B)

6. Lee S, James WC, et al. Evaluation of hallux alignment and functional outcome after isolated tibial sesamoidectomy. Foot Ankle Int 2005; 26(10) : 803-809. (Level of evidence : 2B)