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.
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