Triplane Fracture, Tibia, Ankle, ORIF Fixation, vs Trimalleolar Fracture

Triplane Fracture:

• What is a Triplane Fracture?
• Tibia Involvement
• Ankle Implications
• ORIF Fixation
• Comparison vs Trimalleolar Fracture

What is a Triplane Fracture?

A triplane fracture is a complex, pediatric ankle fracture that occurs across three planes: sagittal, coronal, and transverse. It is unique to adolescents because it involves the distal tibial physis (growth plate), which is partially fused during early adolescence. The fracture typically occurs during sports or falls that twist the ankle, placing rotational stress across the growth plate.

Clinically, triplane fractures are difficult to detect on standard X-rays due to their three-dimensional nature. They are often classified into two or three fragments based on fracture pattern and displacement. Prompt recognition is critical to prevent growth disturbances and long-term ankle deformities. Advanced imaging, such as CT scans, is often required for accurate diagnosis and preoperative planning.

Tibia Involvement

The distal tibia is the main bone affected in triplane fractures. The fracture traverses the metaphysis, physis, and epiphysis, which can disrupt normal growth if not properly managed. This involvement is a defining feature distinguishing triplane fractures from simple metaphyseal or epiphyseal injuries.

Because the distal tibial physis contributes significantly to longitudinal growth, any misalignment or malunion can lead to leg length discrepancies or angular deformities. Pediatric orthopedic surgeons carefully evaluate tibial involvement to determine the need for surgical intervention versus conservative management with casting or bracing.

Ankle Implications

Triplane fractures often extend into the ankle joint, causing articular disruption. This can lead to joint incongruity, post-traumatic arthritis, and chronic pain if left untreated. The fracture pattern may involve both the medial and lateral malleoli as well as the posterior tibial fragment.

Swelling, tenderness, and limited ankle motion are common clinical signs. Due to the intra-articular nature of the fracture, anatomical reduction is critical. Inadequate treatment can result in long-term instability, impaired function, and difficulty in sports or daily activities.

ORIF Fixation

Open reduction and internal fixation (ORIF) is often required for displaced triplane fractures. The procedure involves surgically realigning the fracture fragments and stabilizing them with screws or plates. This ensures proper healing and preserves joint congruity.

Postoperatively, patients are typically immobilized in a cast or boot, followed by gradual weight-bearing and physical therapy. ORIF reduces the risk of growth disturbances, malunion, and post-traumatic arthritis. Surgeons must carefully plan screw placement to avoid damaging the physis and preserve future growth.

Comparison vs Trimalleolar Fracture

A trimalleolar fracture occurs in adults and involves fractures of the medial malleolus, lateral malleolus, and posterior malleolus of the ankle. Unlike triplane fractures, trimalleolar fractures are extra-physeal (no growth plate involvement) and typically result from high-energy trauma such as falls or motor vehicle accidents.

Triplane fractures are unique to adolescents and involve the physis, metaphysis, and epiphysis, whereas trimalleolar fractures affect mature bone. Both fractures may require ORIF if displaced, but triplane fractures have additional considerations regarding future growth and joint development. Understanding the difference is critical for appropriate surgical planning and long-term outcomes.