21 - Sesamoid Injuries

Question 1

Sesamoid function

Answer 1

• Bear Weight
• Mechanical Advantage
• FHL (flexor hallucis longus)
• Decrease load of 1st MPJ

Question 2

Sesamoid fractures - general

Answer 2

• Usually results from falls, forced DF or repetitive stress
• Certain sports more prone to injury (dance, running, step class)
• Direct force in sagittal plane
• Stepping on ball of foot
• Overuse

Question 3

Sesamoid fractures - clinical presentation

Answer 3

• Pain on palpation
• Pain with dorsiflexion
• Ataxic gait (walking on outside of foot to avoid putting pressure on the sesamoids

Question 4

Sesamoid fractures - radiographs

Answer 4

• Sesamoid axial
• Bone scan
• MRI/CT
• Contralateral/serial radiographs
• NOTE: AP radiograph may give you an idea, but the gold standard is to get the SESAMOID AXIAL or plantar axial in order to ISOLATE the sesamoids (and even then, it may be difficult)
• May have to rely on additional studies (bone scan, CT, MRI) in order to distinguish a bipartite sesamoid or a fractured sesamoid
• Bipartite sesamoid = two parts that never fused

Question 5

Incidence of sesamoid fractures

Answer 5

• Sesamoid fractures are very rare fractures
• Tibial Sesamoid is fractured more often
• Tibial sesamoid is larger and bears more weight – meaning it is more prone to fracture

Question 6

Sesamoid fractures - fracture patterns

Answer 6

• Usually transverse or comminuted
• Transverse fracture makes it hard to distinguish from a bipartite sesamoid
• Rare for both to be fractured, so look at contralateral radiographs

Question 7

Sesamoid fractures - conservative options

Answer 7

• Non-weightbearing

- Bone stimulation

Question 8

Sesamoid fractures – Surgical Options

Answer 8

• ORIF (good luck – not an easy or successful procedure)

- Excision of sesamoid (partial/total excision)

Question 9

Sequelae of removal of a sesamoid

Answer 9

o Fibular sesamoid removal will lead to hallux varus

o Tibial sesamoid removal will lead to hallux valgus

Question 10

CASE STUDY

Answer 10

o A 33-year-old active female began to experience episodes of pain under the tibial sesamoid. She reported walking in the airport and experiencing a pain under the first metatarsophalangeal joint while in a high heel. She initially presented to another podiatrist, who diagnosed her with ‘fractured tibial sesamoid’. He instituted conservative treatment including padding and a local steroid injection. She did well for several months, but continued to have episodes of increasing pain.
o She presented to our office and clinical evaluation revealed pain directly under the tibial sesamoid. She was ambulating and wearing shoes, but had episodes of pain and signs of non-healing of the tibial sesamoid fracture

Question 11

Physical exam

Answer 11

o Physical exam reveals neurovascular status is intact. Muscle strength is normal. Pt. has pain on palpation of the tibial sesamoid and pain plantar first metatarsal with end range of dorsiflexion. No erythema or swelling noted.

Question 12

Radiographs

Answer 12

o Fractures tibial sesamoid

o No additional studies are needed

Question 13

Treatment

Answer 13

o Since prior treatment has not resolved pain, go ahead with excision