Distal Tibial Physeal Injuries

Distal Tibial Physeal Injuries occur in two main contexts:

1. Standard Salter-Harris Fractures: Similar to other physes.
2. Transitional Fractures (Tillaux, Triplane): Unique to adolescents due to asymmetric physeal closure.

• Epidemiology:
  • Transitional fractures occur between ages 12-15 years.
  • More common in boys (due to later physeal closure).
  • Standard SH injuries can occur at any age.
• Mechanism:
  • External rotation is the most common mechanism for transitional fractures.
  • The AITFL (anterior inferior tibiofibular ligament) avulses the anterolateral epiphysis.

Physeal Closure Pattern The distal tibial physis closes asymmetrically over 18 months:

1. Central: First to close (approximately age 12-14).
2. Medial (Anteromedial): Closes next.
3. Lateral (Posterolateral): Last to close (approximately age 14-16).

Tillaux Fracture

• The lateral physis is still open when the external rotation force occurs.
• The AITFL attaches to the anterolateral epiphysis.
• External rotation avulses the anterolateral fragment (SH Type III).

Triplane Fracture

• More complex pattern with fracture in three planes.
• Sagittal (through the epiphysis - like Tillaux).
• Horizontal (through the physis).
• Coronal (through the metaphysis - like SH II).
• Can be 2-part, 3-part, or 4-part.

History:

• Mechanism: Twisting (external rotation)? Inversion? Direct trauma?
• Age: Transitional fractures occur at ages 12-15.

Physical Exam:

1. Inspection: Swelling, ecchymosis, deformity.
2. Palpation: Tenderness over the physis (anterolateral for Tillaux).
3. ROM: Limited by pain.
4. Neurovascular: Document status.
5. Fibula: Check for associated fibular fracture.

Imaging:

• X-ray (AP, Lateral, Mortise): Standard. May show widening or fragment.
• CT Scan with 3D Reconstruction: ESSENTIAL for transitional fractures. X-ray underestimates displacement.
• Allows measurement of articular step-off and surgical planning.

Key Surgical Points

• Always obtain post-op CT to confirm reduction.
• Screw fixation is superior to K-wires for compression.
• Screw placement should be parallel to the joint and avoid crossing the physis.

• Immobilization: Below-knee cast for 4-6 weeks.
• Weight Bearing: Non-weight bearing initially, then WBAT at 4-6 weeks.
• Post-Op CT: Essential to confirm reduction, especially for triplane.
• Follow-Up: At 2 weeks (wound check), 6 weeks (cast removal), and 3 months.
• Growth Surveillance: Less critical than at other physes due to near-skeletal maturity.

• Non-Displaced: Excellent outcomes with casting.
• Displaced (Anatomically Reduced): Good outcomes. Low arthritis risk.
• Malunited (Greater Than 2mm): Risk of post-traumatic arthritis.
• Growth Arrest: Uncommon because these fractures occur near skeletal maturity. If significant growth remains, monitor.

• The 2 mm threshold is convention, not high-level evidence. It derives from articular-step extrapolation and small series; no randomised data define the exact cut-off. Some authors accept up to 2.5 mm in the very mature ankle, while others reduce any visible step in a younger adolescent. Know that it is a pragmatic threshold examiners expect, but be ready to justify deviation by remaining growth and articular location.
• Routine CT vs selective CT. CT clearly changes classification and the operative decision in transitional fractures (Eismann, Nenopoulos), but it irradiates the immature skeleton. Practice varies between obtaining CT on all suspected transitional fractures and reserving it for those that appear displaced on radiographs.
• Closed vs open reduction for the displaced Tillaux. Closed reduction (internal rotation) with percutaneous screw fixation can succeed, but periosteal or AITFL interposition may block it. There is no consensus on how many closed attempts are acceptable before converting to open reduction; repeated forceful manipulation itself raises physeal-arrest risk.
• Need for, and timing of, post-operative CT. Post-operative CT confirms reduction but adds radiation; some surgeons rely on intra-operative fluoroscopy and arthroscopic visualisation instead.
• Growth surveillance. Because these injuries cluster near maturity, the value of prolonged Harris-line/scanogram follow-up is debated - displacement and SH II pattern (not the transitional patterns) are the real arrest predictors (Leary).

Global epidemiology

• Distal tibial physeal fractures are among the most common physeal injuries, peaking in the adolescent growth spurt (girls roughly 8-14, boys roughly 10-16 years).
• Triplane fractures represent approximately 5-10% of paediatric ankle physeal injuries (6% in the original Cooperman/Spiegel series); Tillaux is rarer and seen in the narrower 12-15 year window.
• Mechanism is overwhelmingly low-energy sport/recreational external rotation; both patterns reflect the ascending (central to medial to lateral) physeal closure sequence rather than a discrete injury entity.

Where guidance converges (society and consensus positions)

There is no genuine guideline-level disagreement on the core principles: the 2 mm threshold, CT for transitional patterns, and anatomical articular reduction are universal. Differences are in access, not recommendation.

Registry note: There is no dedicated implant registry for paediatric transitional ankle fractures (these are low-volume, screw-only constructs). The evidence base is therefore case series and systematic review rather than registry survivorship - this is itself an exam point distinguishing it from arthroplasty topics.

High- vs limited-resource practice variation

• Well-resourced: routine pre-operative CT with 3D reconstruction, arthroscopic-assisted or fluoroscopic percutaneous cannulated-screw fixation, and confirmatory post-operative CT.
• Limited-resource: reliance on plain mortise/lateral radiographs and stress/internal-rotation views, with a lower threshold for open reduction when CT is unavailable to confirm the closed result. The principle (anatomical articular reduction) does not change; only the imaging confirmation does.

What is a transitional fracture? A transitional fracture is a type of ankle fracture that occurs in adolescents as the growth plate is closing. The growth plate does not close all at once - it closes in stages. During this transition, certain fracture patterns can occur.

What are Tillaux and Triplane fractures? These are the two main types of transitional fractures. They involve the ankle joint, and if the fracture is significantly displaced, surgery is needed to prevent arthritis.

How is displacement measured? A CT scan is used to measure exactly how much the fracture has shifted. If the shift is more than 2mm, surgery is usually recommended.

What is the treatment?

• If less than 2mm shifted: A cast for 4-6 weeks.
• If more than 2mm shifted: Surgery to realign the bones (screws are often used).

What is the outcome? Most patients do very well. Because these fractures occur near the end of growth, growth problems are uncommon.

Phase 1: Immobilization (0-6 weeks)

• Below-knee cast.
• Non-weight bearing initially.
• Toe wiggling and calf pumps.

Phase 2: Early Mobilization (6-10 weeks)

• Cast removal.
• Ankle ROM exercises (dorsiflexion, plantarflexion).
• Progressive weight bearing.

Phase 3: Strengthening (10-16 weeks)

• Resistance exercises (theraband).
• Proprioception and balance training.
• Gait normalization.

Phase 4: Return to Sport (4-6 months)

• Sport-specific training.
• Full ROM and strength.
• Clearance by surgeon.

The adolescent with a twisted, swollen ankle after sport is the classic crossover - distinguishing a transitional fracture from a "sprain" is the high-yield decision.