Our expert podiatrists know a thing or two when it comes to foot-related injuries. Our Sports & Spinal Podiatrists have defined sesamoid injuries, how they occur, the risk factors involved, and the available treatment options.

Sesamoids, What are They?

The 1^st metatarsophalangeal (MP) joint in the forefoot consists of 4 bones;

The proximal phalanx of the hallux,

The 1^st metatarsal and,

Two sesamoid bones.

Sesamoid bones play an important role in the function of the big toe. Similarly, like that of the patella in the knee. Located within the flexor hallucis brevis tendons, the sesamoids:

• Functionally lengthen the 1^st metatarsal
• Protect the flexor hallucis longus tendon
• Assist in weight transfer from the lateral to the medial aspect of the forefoot

Risk Factors & Symptoms

Injuries to the sesamoids may be caused by landing after a jump, sprinting or dancing (activities that increased forefoot pressure) or following traumatic dorsiflexion of the big toe.

Symptoms often present as localised pain to the plantar 1^st MP joint with weight-bearing through the forefoot, worse with sports involving higher forefoot loading and change of direction (i.e. basketball or tennis) or stair climbing.

The athlete may attempt to avoid painful toe-off through the 1^st MP joint by an altered walking pattern. Examination of the foot reveals pain and tenderness of one or both of the sesamoids, often accompanied by swelling, warmth and redness. Moving the 1^st MP joint against resistance is often painful, restricted and/or weak.

The larger, medial sesamoid (77%) is more frequently injured compared to the lateral sesamoid (23%), due to the comparatively increased weight-bearing forces it becomes exposed to.

Forefoot pronation and progressive hallux valgus can contribute to this presentation and can influence the smooth gliding of the sesamoid bones beneath the 1^st MP joint.

Other Risk Factors Include:

• Repetitive trauma
• Mechanical overload with pes cavus foot type
• Significant plantarflexed 1^st ray
• Ankle equinus⁵

In conjunction with physical examination, further radiology investigation is required to examine and diagnose the precise pathology that presents with sesamoid pain. X-Rays with a special view of the sesamoids are frequently used first, followed by an MRI or Bone Scan.

Treatment Options

A goal of treatment is to reduce direct pressure on the sesamoid bones, allowing time and capacity to heal. Load and physical activity changes, icing, and pain-relief & anti-inflammatory medication are used initially to manage pain, in addition to accommodative padding within footwear.

Foot orthoses, with this prescribed feature, can address biomechanics and reduce load where needed. A gradual return to full-weight bearing and sporting activity can be achieved with footwear changes (stiff-soled or curve forefoot sections), re-introducing controlled loading through the 1^st MP joint.