# CIM Case: Triplane Fracture ## Clinical Scenario **Patient:** 12-year-old girl **Presentation:** Fall from trampoline 4 hours ago, landed awkwardly on right ankle, immediate pain and swelling, unable to weight-bear **Relevant history:** External rotation mechanism, no previous ankle injuries, healthy otherwise, started menarche 6 months ago (approaching skeletal maturity) **Examination findings:** - Swelling and bruising around right ankle (lateral and medial) - Tenderness over lateral and posterior ankle - Unable to range ankle due to pain - No open wounds - No bony deformity visible externally - Toes warm, pink, moving, sensation intact - Dorsalis pedis and posterior tibial pulses palpable --- ## Investigations Provided ### Laboratory Results | Test | Result | Normal Range | Interpretation | |------|--------|--------------|----------------| | N/A | - | - | Bloods not routinely required for isolated fracture | ### Imaging **Image 1: AP, Lateral, and Mortise Ankle Radiographs** **Radiological features:** - AP view: Vertical fracture line through lateral distal tibial epiphysis (Salter-Harris IV component) - Lateral view: Posterior metaphyseal fragment (Salter-Harris II component) - Mortise view: 3mm articular step visible at tibial plafond - Physis partially closed centrally, open peripherally (transitional physis) - Fibula intact - No talar shift or widening of mortise **Image 2: CT Scan with 3D Reconstruction** **CT findings:** - Three-part triplane fracture confirmed - Epiphyseal fragment (anterolateral) with 4mm displacement - Metaphyseal fragment (posterior) with 3mm displacement - Intact central tibial portion - Articular step 3.5mm at tibial plafond - No fibula fracture - No additional fragments ## Questions & Model Answers **Definition:** A triplane fracture is a transitional fracture of the distal tibia that occurs in three planes: - **Sagittal plane:** Through the epiphysis - **Axial/horizontal plane:** Through the physis - **Coronal plane:** Through the metaphysis **Why This Age?** **Physeal Closure Pattern:** The distal tibial physis closes in a characteristic sequence over 18 months: 1. **Central closure first** (Kump's bump) 2. **Medial closure** next 3. **Posterolateral closure** 4. **Anterolateral closure LAST** **Transitional Period:** - Occurs between ages 12-15 years - Physis is partially closed, partially open - Creates a "weak link" in the partially closed portion - External rotation force propagates through these planes **Mechanism:** - External rotation of foot on fixed tibia - Force creates fracture pattern that follows the partially closed/open physis - Similar to adult ankle fracture mechanism but different pattern due to physis **Classification of Transitional Fractures:** | Type | Description | Planes Involved | |------|-------------|-----------------| | **Tillaux** | Anterolateral epiphysis only | Sagittal + Axial (SH III) | | **Triplane 2-part** | Epiphyseal + metaphyseal | All 3 planes | | **Triplane 3-part** | Separate epiphyseal and metaphyseal fragments | All 3 planes | | **Triplane 4-part** | Multiple fragments | All 3 planes | > **Consultant Tip:** Triplane fractures are unique to adolescents. The pattern reflects the asymmetric physeal closure of the distal tibia. **Initial Imaging:** **Plain Radiographs (3 views):** | View | What to Look For | |------|------------------| | **AP** | Vertical epiphyseal fracture line, articular incongruity | | **Lateral** | Posterior metaphyseal fragment, step at plafond | | **Mortise** | Articular displacement, mortise alignment | **Radiographic Features Suggesting Triplane:** - Different fracture patterns on AP vs lateral views - AP: looks like Tillaux (Salter-Harris III) - Lateral: looks like Salter-Harris II - This "paradox" = triplane fracture **CT Scan - ESSENTIAL:** | Purpose | Why Needed | |---------|------------| | **Confirm diagnosis** | Defines true fracture pattern | | **Measure displacement** | Accurate articular step measurement | | **Count fragments** | 2-part vs 3-part vs 4-part | | **Plan surgery** | Entry point, screw trajectory | **CT Protocol:** - Thin cuts (1-2mm) through distal tibia - Sagittal and coronal reformats - 3D reconstruction helpful for planning **Displacement Threshold:** | Displacement | Management | |--------------|------------| | <2mm articular step | Non-operative (cast) | | ≥2mm articular step | Operative (ORIF) | **This Patient:** 3.5mm step on CT → OPERATIVE > **Consultant Tip:** Always get CT for suspected triplane fracture. X-rays underestimate displacement and miss fracture complexity. **Indications for Non-operative Management:** - Articular step <2mm on CT - Acceptable alignment - Stable fracture pattern - Compliant patient and family **Technique:** **Initial Management:** - Backslab (below knee posterior splint) - Elevation and ice - Analgesia - Non-weight-bearing **Definitive Casting:** - Above-knee cast for 2-3 weeks (prevents rotation) - Then below-knee cast for 3-4 weeks (total 6 weeks) - Cast in neutral ankle position **Follow-up Protocol:** | Time | Assessment | |------|------------| | 1 week | Check X-ray in cast, assess for displacement | | 2-3 weeks | Repeat X-ray, convert to below-knee if stable | | 6 weeks | X-ray, assess healing, remove cast if healed | | 3 months | Final X-ray, assess for growth disturbance | **Weight-bearing:** - Non-weight-bearing for 4-6 weeks - Progress to full weight-bearing when healed **Expected Outcomes:** - Excellent outcomes if displacement <2mm maintained - Very low rate of physeal arrest (physis nearly closed already) - Full ROM expected **Red Flags During Treatment:** - Loss of reduction on X-ray → consider surgery - Persistent pain → repeat imaging - Skin issues → cast modification > **Consultant Tip:** Even minimally displaced triplane fractures need close follow-up. Check at 1 week to ensure no displacement. **Indications for ORIF:** - Articular step ≥2mm - Unable to achieve closed reduction - Intra-articular debris/interposition **Preoperative Planning:** - Review CT carefully (3D reconstructions helpful) - Identify number of fragments - Plan screw trajectories - Discuss with family: surgical vs non-operative risks **Surgical Technique:** **Positioning:** - Supine on radiolucent table - Bump under ipsilateral hip - Tourniquet (optional) - Ensure adequate fluoroscopy access **Approach:** - **Anterolateral incision** for lateral epiphyseal fragment - May need **anteromedial incision** if medial reduction needed - Avoid extensive soft tissue stripping **Reduction:** | Step | Technique | |------|-----------| | **Visualise fracture** | Direct visualization through incision | | **Remove haematoma/debris** | Irrigate joint | | **Reduce epiphysis** | Use dental pick, small elevators | | **Reduce metaphysis** | May reduce with epiphysis, or separately | | **Confirm on fluoro** | AP, lateral, mortise views | **Fixation:** | Fragment | Fixation | |----------|----------| | **Epiphyseal** | 4.0mm cannulated screws (parallel to physis) | | **Metaphyseal** | Cannulated screw or K-wire | **Screw Placement Principles:** - Screws parallel to physis (avoid crossing physis if possible) - In adolescents, crossing physis acceptable (nearly closed) - Countersink screw heads - Confirm position on multiple views **Closure:** - Irrigate - Layered closure - Below-knee backslab **Postoperative Care:** - Non-weight-bearing 4-6 weeks - Convert to cast when swelling settles - Serial X-rays at 2, 4, 6 weeks > **Consultant Tip:** Use small incisions and indirect reduction where possible. Direct visualization of articular surface ensures anatomic reduction. **Obstacles to Closed Reduction:** | Structure | Mechanism | |-----------|-----------| | **Periosteum** | Interposed between fragments (most common) | | **Anterior tibial tendon** | Caught between fracture fragments | | **Extensor hallucis longus** | Wrapped around fragment | | **Neurovascular bundle** | Rarely interposed (check carefully!) | **Intraoperative Recognition:** - Fracture reduces anatomically on fluoroscopy but fragments separate - Soft tissue "block" palpable - Direct visualisation shows interposition **Management:** **If Closed Reduction Fails:** 1. Proceed to open reduction 2. Extend incision as needed 3. Identify and extract interposed tissue 4. Reduce directly under vision 5. Fix as planned **If Open Reduction Still Difficult:** - Consider additional incision (anteromedial for medial fragments) - May need to remove small free fragments if preventing reduction - Rarely, accept minor residual displacement rather than cause more soft tissue damage **Documentation:** - Document what was interposed - Document final reduction quality - Intraoperative photographs helpful **Outcomes After Open vs Closed Reduction:** - Both have excellent outcomes if anatomic reduction achieved - Open reduction may have slightly higher stiffness rate - Key is final articular alignment, not approach used > **Consultant Tip:** Don't force a closed reduction. If it's not reducing, something is in the way. Open reduction is safe and allows direct confirmation of articular reduction. **Potential Complications:** **Early Complications:** | Complication | Incidence | Prevention/Management | |--------------|-----------|----------------------| | **Wound infection** | 1-2% | Prophylactic antibiotics, careful soft tissue handling | | **Hardware prominence** | 10-20% | Countersink screws, may need removal later | | **Loss of reduction** | Rare if fixed | Adequate fixation, follow-up X-rays | | **Compartment syndrome** | Very rare | Clinical monitoring | **Late Complications:** | Complication | Incidence | Notes | |--------------|-----------|-------| | **Physeal arrest** | <5% | Physis mostly closed anyway, rarely significant | | **Angular deformity** | Rare | From physeal bar if occurs | | **Leg length discrepancy** | Rare | Minimal growth remaining | | **Post-traumatic arthritis** | Rare | Related to articular incongruity >2mm | | **Ankle stiffness** | 5-10% | Usually resolves with physiotherapy | **Growth Disturbance:** | Factor | Risk Level | |--------|------------| | Age >12, near maturity | Low risk | | Minimal growth remaining | Unlikely to be significant | | Anatomic reduction | Protective | **Follow-up Protocol:** | Time | Assessment | Purpose | |------|------------|---------| | 2 weeks | Wound check, X-ray | Healing, no displacement | | 4 weeks | X-ray | Fracture healing | | 6 weeks | X-ray, remove cast | Union assessment | | 3 months | X-ray, clinical exam | Final healing, ROM | | 6-12 months | X-ray | Physeal status, any growth disturbance | | Hardware removal | 6-12 months | If symptomatic | **Return to Activity:** | Activity | Timeline | |----------|----------| | Walking | 6 weeks post-union | | Running | 3 months | | Sport | 3-6 months (depending on sport) | **Expected Outcome:** - Excellent in >90% if anatomic reduction achieved - Full ROM expected - Return to all activities including competitive sport > **Consultant Tip:** Outcomes are excellent for triplane fractures. Physeal arrest is rare because the physis is mostly closed. Focus on articular reduction. --- ## Key Teaching Points ### Pattern Recognition **This pattern suggests Triplane Fracture:** - Adolescent (12-15 years) with ankle injury - External rotation mechanism - Different fracture patterns on AP vs lateral X-rays - Salter-Harris III appearance on AP, SH II on lateral - Partially closed physis on imaging **Distinguish from Tillaux Fracture:** | Feature | Triplane | Tillaux | |---------|----------|---------| | Planes | 3 (sagittal, axial, coronal) | 2 (sagittal, axial) | | Metaphyseal fragment | Yes | No | | SH classification | SH IV equivalent | SH III | | X-ray appearance | Different AP vs lateral | Similar AP and lateral | **Key Imaging Clue:** If AP looks like SH III and lateral looks like SH II → think TRIPLANE ### Critical Management Points 1. **Always get CT** - X-rays underestimate displacement and miss complexity 2. **<2mm articular step = non-operative** - cast for 6 weeks 3. **≥2mm articular step = ORIF** - anatomic reduction essential 4. **Periosteum may block reduction** - open if closed reduction fails 5. **Physeal arrest rare** - physis nearly closed, minimal growth remaining 6. **Excellent prognosis** - >90% good/excellent outcomes with anatomic reduction --- ## Common Examiner Follow-ups **Q: "What is the sequence of distal tibial physeal closure?"** The distal tibial physis closes asymmetrically over 18 months: 1. **Central** (Kump's bump) - first to close 2. **Medial** 3. **Posterolateral** 4. **Anterolateral** - last to close This creates the "transitional" period where only part of the physis is open, predisposing to Tillaux and triplane fractures. The anterolateral fragment in a Tillaux is the "last to close" region. --- **Q: "What is the difference between a 2-part and 3-part triplane fracture?"** | Type | Description | Fragments | |------|-------------|-----------| | **2-part** | Epiphyseal and metaphyseal fragments connected | 1 large lateral fragment + medial tibial shaft | | **3-part** | Epiphyseal and metaphyseal fragments separate | Anterolateral epiphysis + posterior metaphysis + medial shaft | | **4-part** | Additional fragment(s) | Variable | Fixation principles are the same - restore articular congruity and stabilise fragments. 3-part may need more screws. --- **Q: "Can you treat a 3mm step non-operatively?"** Traditional teaching is ≥2mm requires ORIF due to risk of post-traumatic arthritis. However: - Some argue 2-3mm may be acceptable in weight-bearing tolerant ankle - Long-term studies show poor outcomes with >2mm step - **Standard of care remains operative for ≥2mm** - Document discussion with family if considering conservative for borderline cases --- **Q: "This child has a triplane with a fibula fracture. How does that change things?"** A fibula fracture with triplane is unusual but can occur: - Suggests higher energy mechanism - May have syndesmotic component - **Assess syndesmosis** on CT and clinically - Fix fibula if unstable or displaced - May need syndesmotic fixation if disrupted - Otherwise, same principles apply for tibial fixation --- ## Related Topics - Tillaux Fracture - Salter-Harris Classification - Adolescent Ankle Fractures - Physeal Injuries - Ankle ORIF Techniques - Paediatric Trauma Principles