Foot Fractures

Foot Fractures - Bones & Breaks 101

• Hindfoot: Talus (connects to tibia/fibula), Calcaneus (heel bone).
  • Common: Calcaneal fractures (axial load, e.g., fall from height).
• Midfoot: Navicular, Cuboid, 3 Cuneiforms. Forms arches.
  • Key: Lisfranc joint complex (tarso-metatarsal articulation); injury often missed.
• Forefoot: 5 Metatarsals (MT), 14 Phalanges.
  • Common: Stress fractures (e.g., March fx - 2nd/3rd MT), Jones fx (base of 5th MT).

⭐ Calcaneal Bohler's angle < 20° (normal 20-40°) suggests calcaneal fracture and posterior facet collapse.

Foot Fractures - Heel Shatter Showdown

• Calcaneal Fractures: Most common tarsal #; axial load injury.
• Classification:
  • Essex-Lopresti: Tongue-type vs. Joint depression.
  • Sanders (CT): Types I-IV (posterior facet involvement).
• Key Angles:
  • Bohler's: Normal $20^\circ-40^\circ$. < $20^\circ$ = severe collapse.
  • Gissane's (Critical): Normal $120^\circ-145^\circ$.
• Surgical Indications:
  • Displaced intra-articular (> 2mm step-off).
  • Bohler's angle < $20^\circ$.
  • Widening, varus malunion.

⭐ ~75% of calcaneal fractures are intra-articular, affecting the subtalar joint.

Foot Fractures - Talar Tilt & Trauma

• Blood Supply: Precarious, retrograde (posterior tibial a. → artery of tarsal canal). High AVN risk.
• Mechanism: Forced hyperdorsiflexion of ankle with axial load (e.g., MVA dashboard injury, fall from height).
• Hawkins Classification (Talar Neck Fx):
  • Type I: Undisplaced. AVN: 0-15%.
  • Type II: Subtalar dislocation/subluxation. AVN: 20-50%.
  • Type III: Subtalar + Tibiotalar dislocation. AVN: 80-100%.
  • Type IV (Canale): Type III + Talonavicular dislocation. AVN: ~100%.
  • 📌 Mnemonic: AVN risk ↑ with ↑ type number.
• Management:
  • Type I (truly undisplaced): Non-operative (cast immobilization).
  • Type II-IV: Urgent ORIF to ↓ AVN risk.

⭐ The artery of the tarsal canal (branch of posterior tibial artery) is the primary supply to the talar body; injury dramatically ↑ AVN risk post-fracture.

Foot Fractures - Arch Enemies & Toe Woes

• Lisfranc Injury (Tarsometatarsal Joint):

  • Mechanism: Axial load on plantarflexed foot; crush injury.

  • Diagnosis: Plantar ecchymosis, tenderness over TMT joints, diastasis > 2mm (1st-2nd MT bases), "fleck sign" (avulsion of Lisfranc ligament).

  • Management (Hardcastle/Myerson classification guides treatment):

  ⭐ "Fleck sign" - a small bony fragment seen in the space between the 1st and 2nd metatarsal bases - is pathognomonic for Lisfranc ligament injury.

• Navicular Fractures:

  • High risk of Avascular Necrosis (AVN), especially central third (watershed area).

  • Watson-Jones Classification: Type I (tuberosity), Type II (dorsal lip/body, undisplaced), Type III (body, displaced), Type IV (stress fracture).

  • Management: I (cast); II (cast/ORIF if large); III (ORIF); IV (NWB, prolonged immobilization).

• 5th Metatarsal Base Fractures:

  • Jones Fracture: Zone 2 (metaphyseal-diaphyseal junction); ↑ risk of non-union/delayed union due to tenuous blood supply. Rx: NWB cast for 6-8 wks, or IM screw fixation (esp. athletes).

  • Avulsion Fracture (Pseudo-Jones/Dancer's): Zone 1 (tuberosity, peroneus brevis insertion); Rx: symptomatic, WBAT in hard-soled shoe/boot.

• March Fracture:

  • Stress fracture, typically of 2nd or 3rd metatarsal shaft.
  • Mechanism: Repetitive overuse.
  • Rx: Rest, activity modification, stiff-soled shoe or boot. X-rays may be initially negative.

High‑Yield Points - ⚡ Biggest Takeaways

• Jones fracture: 5th metatarsal base (metaphyseal-diaphyseal junction); high non-union risk.
• Lisfranc injury: TMT joint disruption; look for fleck sign (2nd MT base avulsion) or >2mm diastasis.
• Calcaneal fractures: Axial load (fall); Bohler's angle <20°. Associated spine fractures common.
• Talar neck fractures: High AVN risk, especially displaced (Hawkins type II-IV).
• March fracture: Stress fracture of 2nd/3rd metatarsal diaphysis.
• Navicular stress fractures: Vague midfoot pain in athletes; often needs CT/MRI for diagnosis.