Supracondylar fracture of humerus

Paediatric Supracondylar Fracture of the Humerus

Common Nerve Palsies

• Flexion-type fracture: Most commonly injures the ulnar nerve.
• Extension-type fracture: Commonly injures the anterior interosseous nerve (AIN).
• Documentation: Clear pre-op documentation of any nerve injury is critical as any nerve can be involved.
• Compartment syndrome risk: Increased with nerve injury.

Vascularity

Pulseless Perfused Hand:

• Signs: Pulse not palpable, but capillary refill (CR) < 2 seconds, and the hand is warm.
• Management: Must go to the operating room urgently, regardless of the time.
• Complications: If left untreated, perfusion may be compromised.

Indications for Anterior Approach:

• Notify vascular surgeons.
• Pulseless, pale hand: Requires an anterior approach using a transverse incision extended in a "boat race" fashion (proximal medial, distal lateral).
• Compartment syndrome risk is higher, particularly with median nerve palsy.
• Test: Flexor digitorum superficialis (FDS) function in fingers (better than sensory testing).

If Pulse Absent After Reduction and Pinning:

1. Check for anatomical reduction: Non-anatomic reduction may indicate arterial incarceration.
2. If the hand is perfused:
   • Use a windowed plaster to monitor the area with Doppler.
   • Admit for 24-48 hours to monitor vascularity.
   • Safe discharge if no compartment syndrome and good perfusion after 48 hours.
3. Pulse lost post-reduction:
   • Presume vessel incarceration or kinking.
   • Open exploration is required to free the artery, even if a Doppler pulse is present.

Compartment Syndrome

• Possible even with pink hand and normal capillary refill.
• Main indicators:
  • Increasing need for analgesics.
  • Persistent absence of pulse on Doppler and palpation.
  • Inability to flex fingers actively (volar compartment compromise).
• Examine for swelling and firmness in the forearm.
• Management:
  • Keep the arm out of plaster.
  • Elevate above heart level.
  • Monitor closely in the hospital to prevent Volkmann's ischemic contracture.

Pinning Pattern

Lateral Pinning:

• Study (Skaggs et al.): Lateral pinning effective in 250 cases/year, with only 2 needing medial pinning.
• Use 2 or 3 lateral wires.
• Indications: Oblique fractures (high lateral to low medial).
• Place wires in thirds at the fracture level.
• Ensure wires are bicortical.
• Avoid high lateral wires to prevent radial nerve injury.

Medial Pinning:

• Indications: Unstable fractures or fractures with medial comminution (varus risk).
• Biomechanics: Cross wires provide a stronger configuration.
• Useful for rare oblique fractures (high medial to low lateral).

Assessment of Reduction

• Bauman’s angle: Should be preserved.
• Anterior humeral line: Should intersect the capitellum.
• Bauman's angle: Humerocapitellar angle (75° ± 10°).

Urgent Cases

• Vascular issues: Compartment syndrome risk.
• Nerve issues: Compartment syndrome risk.
• Skin blanching or open fractures: Require urgent attention.

Open Reduction Approaches

• Posterior approach: Risk of avascular necrosis (AVN) and stiffness.
• Anterior approach: Used for vascular injuries (transverse or boat race incision).
• Medial or lateral approaches: Both acceptable; recent studies show no increase in stiffness with open reduction.

Acceptable Deformity Post-Reduction

• Must not be in varus.
• Any rotation is unacceptable.
• Anterior humeral line: Should intersect the capitellum.
• Coronal plane translation: Acceptable if less than one-third.

Malunion (Cubitus Varus)

• Cause: Varus positioning during fixation, not due to growth problems.
• No growth arrest occurs post supracondylar fractures.
• Remodeling potential in the distal humerus is minimal.
• Complications:
  1. Increased risk of lateral condyle fractures.
  2. Tardy ulnar nerve palsy.
  3. Posterolateral instability in adulthood.
  4. Premature elbow arthritis.
  5. Cosmetic dissatisfaction.
• Correction: Lateral closing wedge supracondylar osteotomy.

Pin Removal

• Supracondylar fractures: Remove pins after 3 weeks.
• Lateral condyle fractures: Remove pins after 4-6 weeks.

Floating Elbow

• Definition: Ipsilateral supracondylar and distal radius fracture.
• Management: Pin both as compartment syndrome risk is higher.
• Pinning Order: Pin the elbow first.

AVN (Avascular Necrosis)

• Rare late complication: AVN of the trochlea.
• Outcome: Causes a fishtail deformity.

Special Fracture Patterns

Flexion-Type Fractures:

• Pin in extension as anterior periosteum is intact in flexion-type fractures.
• Place wires as joysticks, extend the arm, reduce, and drive the wires in.
• Schanz pin: Useful in very unstable cases (placed in the proximal fragment from the posterior side).
• Consider early open reduction.

Type 1 Fractures with Medial Impaction or Comminution:

• Treat surgically to prevent healing in varus.

Type 2 Fractures:

• Any varus or loss of anterior humeral line requires reduction.
• Pin fixation: Reduces risk of loss of reduction, though no consensus exists on pinning.