Summary

A Pilon ("Hammer" in French) fracture is a fracture of the Tibial Plafond (distal articular surface) caused by high-energy Axial Loading (e.g., fall from height or car crash). The talus acts as a hammer, driving up into the tibia and exploding the articular surface. These are limb-threatening injuries due to the catastrophic soft tissue swelling. The Gold Standard management is "Span, Scan, Plan": Initial damage control with an External Fixator (spanning the ankle) to allow soft tissues to settle (10-14 days), followed by definitive ORIF once the "Wrinkle Sign" appears. [1,2,3]

Key Facts

• The Problem: It is not the bone that is the problem; it is the Soft Tissue Envelope. The distal tibia has very thin skin. Swelling causes blistering and necrosis. Operating early through swollen skin leads to infection and amputation.
• Association: 20-30% have associated spinal fractures (Lumbar burst) or calcaneal fractures due to the axial load mechanism. Always examine the spine!
• Arthritis: Despite perfect surgery, 50% of patients develop Post-Traumatic Arthritis within 5 years due to the initial cartilage impact damage (Chondrocyte death).

Clinical Pearls

"Span, Scan, Plan": The mantra for Pilon fractures.

1. Span: Apply Ex-Fix in ER.
2. Scan: CT Scan to map fragments.
3. Plan: Wait 2 weeks, then fix with plates.

"The die-punch fragment": An impacted piece of articular cartilage driven up into the metaphysis. It must be elevated and bone-grafted to restore the joint surface.

"Respect the Soft Tissues": If the skin is blistered, do not operate. Waiting 3 weeks is better than an infected incision at day 3.

                  PILON FRACTURE
                        ↓
            IS THE SKIN SAFE? (WRINKLE SIGN?)
           ┌────────────┴─────────────┐
          NO (Swollen)               YES (Rare)
           ↓                          ↓
    DAMAGE CONTROL (Stage 1)       DEFINITIVE (Stage 2)
  (Span, Scan, Plan)              (ORIF)
    (Delta Frame Ex-Fix)              ↓
           ↓                  ANATOMICAL REDUCTION
      WAIT 10-21 DAYS         (Buttress Plates)
       (CT Scan)                      ↓
           ↓                  EARLY MOTION (NWB)
    WRINKLE SIGN PRESENT?
       (Skin creases)
           ↓
    DEFINITIVE FIXATION

The External Fixator (Delta Frame)

• Goal: Restore length, alignment, and rotation. Pull the talus out of the tibia to prevent cartilage grinding.
• Construct:
  • Proximal Pins: 2x Schanz pins in Tibial Shaft (safe zone).
  • Distal Pin: 1x Trans-calcaneal pin (through the heel).
  • Bars: Construct a triangle ("Delta") to rigidify the frame.
• Timing: Completed in Emergency Theatre (Day 0/1).
• Fibula Fixation: Some surgeons fix the fibula immediately (ORIF) to restore length, if the lateral skin is safe.

Timing

• Wait for the Wrinkle Sign: When you dorsiflex the ankle, skin creases should appear. This indicates edema has subsided. Usually Day 10-14.

Surgical Approaches

1. Anterolateral Approach:
   • Between Peroneus Tertius and Extensor Digitorum Longus.
   • Access to Chaput fragment.
2. Anteromedial Approach:
   • Medial to Tibialis Anterior.
   • Access to Medial Malleolus.
   • Pearl: Keep the skin bridge between AL and AM incisions >7cm to prevent necrosis.

Fixation Strategy (The 4 Steps)

1. Fix Fibula: Restore length (if not done).
2. Reconstruct Articular Block: Put the jigsaw puzzle of the joint surface back together using K-wires. Elevate the "die-punch" fragment.
3. Bone Graft: Fill the void left by elevating the impaction.
4. Buttress Plate: Apply a rigid locking plate to hold the articular block to the shaft.

Assal et al (Span-Scan-Plan)

• Two-staged management significantly reduces severe soft tissue complications compared to early single-stage ORIF in high-energy Pilon fractures.

Ruedi & Allgower (Legacy)

• Originally advocated open reduction. However, their early series had high infection rates, leading to the shift towards Staged Protocols.

Primary Arthrodesis

• For massive Type III comminution where the joint is unsalvageable, some surgeons advocate Primary Fusion (Nail/Plate) immediately, skipping the attempt to save the joint.

The Injury

You have shattered the bottom of your shin bone. It is like dropping a hammer on a meringe. The bone has exploded into the ankle joint.

The Problem

The main problem right now is not the bone, but the skin. Your leg is going to swell up like a balloon. If we cut it open now, it will never heal, and you could lose the leg to infection.

The Plan (Two Operations)

1. Tonight: We will put a metal frame (scaffold) on the outside of your leg to pull the bones out to length and hold them steady. This lets the swelling go down.
2. In 2 Weeks: Once the skin is wrinkly and safe, we will go back firmly, remove the frame, and put plates and screws inside to rebuild the joint surface.

Appearance

It will never be a "normal" ankle again. It will likely be stiff and ache. Our goal is to give you a flat, straight foot to walk on.

Q1: Differentiate between a Pilon fracture and an Ankle fracture. A:

• Pilon: Axial load mechanism. Distal tibial metaphysis involvement. Intra-articular comminution ("Explosion"). Weight-bearing dome involved.
• Ankle: Rotational mechanism. Malleolar involvement. Tibial plafond usually intact.

Q2: What is the "Wrinkle Sign"? A: The reappearance of skin creases on the anterior ankle upon dorsiflexion. It indicates that the interstitial edema has resolved enough to permit safe surgical incision/closure.

Q3: Explain the 3 principles of Ruedi/Allgower fixation. A:

1. Restoration of fibular length.
2. Anatomical reconstruction of the tibial articular surface.
3. Metaphyseal (bone graft) and Buttress plating.

Q4: What is the major risk of placing a medial plate and a lateral incision? A: Narrowing the skin bridge. The bridge between two incisions (e.g., Anteromedial and Anterolateral) should be at least 7cm to preserve the vascularity of the skin flap.

(End of Topic)