Sesamoid Problems

Epidemiology

  • Tibial sesamoid is 10x more commonly bipartite
  • Tibial sesamoid is most commonly affected in all pathologies
  • Athletes are the most commonly affected group

Anatomy

  • Lie within Flexor Hallucis Brevis (FHB) tendon
  • Stabilized by intersesamoid and sesamoidometatarsal ligaments
  • Function:
    • Increase lever arm of FHB
    • Protect Flexor Hallucis Longus (FHL)
    • Distribute load

Common Pathologies

Stress Fracture

  • Most common
  • Avascular necrosis (AVN) & sesamoiditis are likely stress fractures
  • Non-union of the fracture is the main cause of symptoms

Symptomatic Bipartite Sesamoid

  • Usually exacerbated by exercise
  • Can be due to a single traumatic dorsiflexion event – turf toe

Osteoarthritis

  • Sesamoid/MT OA can be isolated or part of Hallux Rigidus

Overload

  • If there is another mechanical foot problem – cavus is typical
  • Plantarflexed 1st ray overloads the sesamoids

Diabetic Feet

  • Ulceration can occur and expose the sesamoids

Clinical Evaluation

History & Examination

  • History of dorsiflexion injury
  • Point tenderness under big toe
  • Exacerbating activities – dorsiflexion (e.g., running)
  • Other foot or systemic problems – cavus?

Imaging

  • Sesamoid view X-rays
  • Standing AP
  • Bone Scan/MRI
  • Bone scan shows high uptake, which is usually enough
    • MRI provides no further relevant information

Management Options

Non-Operative

  • Cut-out padding
  • Rocker bottom shoe
  • Activity modification

Surgical Options

Therapeutic/Diagnostic Injection

  • Probably worthwhile before considering surgery

Sesamoidectomy

  • No significant reduction of FHB power unless both sesamoids resected
  • Complications:
    • Medial plantar digital nerve injury – right over tibial sesamoid
    • Cock-up toe – if both excised
    • Hallux Valgus – medial sesamoidectomy
    • Hallux Varus – lateral sesamoidectomy

Sesamoid Shaving

  • Alternative to sesamoidectomy, partial removal of sesamoid

Bone Grafting

  • Has been successful for non-unions

ORIF

  • ORIF with micro Ackutrak or Barouk screws has good results
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