# CIM Case: Complex Ankle Fracture-Dislocation ## Clinical Scenario **Patient:** 45-year-old woman **Presentation:** Fall down stairs, immediate right ankle pain, unable to weight-bear, witnessed "popping" sound at time of injury **Relevant history:** Previously healthy, non-smoker, no diabetes, no prior ankle injuries, works as a nurse (standing job) **Examination findings:** - Obvious deformity at right ankle - Foot displaced posterolaterally relative to leg - **Tented skin** over medial malleolus (blanching, at risk) - Moderate swelling, no open wound - Dorsalis pedis pulse **weak but palpable** (compare to contralateral) - Capillary refill 4 seconds in toes - Sensation diminished over dorsum of foot - Unable to dorsiflex or plantarflex ankle - Significant tenderness over lateral and medial malleoli - Ecchymosis developing --- ## Investigations Provided ### Imaging **Image 1: AP and Lateral Radiographs of Right Ankle** **Radiological features:** - Trimalleolar fracture-dislocation - Fibula fracture at level of syndesmosis (Weber B equivalent) - Spiral/oblique fracture pattern of fibula - Medial malleolus fracture (transverse) - Posterior malleolar fragment visible on lateral (approximately 25-30% of articular surface) - Talus dislocated posterolaterally - Complete disruption of ankle mortise - No talar dome fracture visible - Tibiofibular clear space widened **Image 2: Post-Reduction AP and Lateral** **Post-reduction findings:** - Talus relocated into mortise - Fibula length and rotation improved - Medial clear space still widened (2mm asymmetry) - Residual posterior subluxation on lateral view - Mortise congruity improved but not perfect --- ## Questions & Model Answers **Diagnosis: Trimalleolar Fracture-Dislocation of the Right Ankle** **Classification:** - **Weber B** (fibula fracture at syndesmosis level) - **Lauge-Hansen: SER (Supination-External Rotation) Stage IV** - Stage I: Anterior tibiofibular ligament rupture - Stage II: Spiral fibula fracture - Stage III: Posterior malleolus fracture or PITFL rupture - Stage IV: Medial malleolus fracture or deltoid rupture **THIS IS AN ORTHOPAEDIC EMERGENCY Because:** | Finding | Concern | Urgency | |---------|---------|---------| | Tented skin over medial malleolus | Skin necrosis risk | Immediate reduction | | Weak dorsalis pedis pulse | Vascular compromise | Immediate reduction | | Diminished sensation | Nerve stretch/ischaemia | Immediate reduction | | Talus dislocation | Cartilage damage | Immediate reduction | **Timing:** - Reduction should occur **within 15-30 minutes** of presentation - Do NOT wait for X-rays before reduction if obvious clinical deformity - Skin necrosis can occur within 6-8 hours of tenting > **Consultant Tip:** Tented skin over the medial malleolus is an emergency. Reduce immediately in ED under sedation. Document neurovascular status before AND after reduction. **Immediate Management Protocol:** **Step 1: Assessment (Rapid)** - Document pulse (DP, PT), capillary refill, sensation, motor - Photograph deformity (for documentation) - Brief history (mechanism, time of injury) **Step 2: Reduction Technique** | Step | Action | |------|--------| | 1 | IV access, procedural sedation (propofol/fentanyl or ketamine) | | 2 | Assistant holds knee flexed to 90° (relaxes gastrocnemius) | | 3 | Grasp heel with one hand, forefoot with other | | 4 | Apply longitudinal traction | | 5 | Reverse displacement (anteriorly if posterolateral dislocation) | | 6 | Correct rotation and angulation | | 7 | Feel/hear "clunk" as talus reduces | **Step 3: Post-Reduction Assessment** - Reassess and document neurovascular status - Check skin viability (should blanching resolve) - Below-knee backslab in neutral dorsiflexion - Mould well around malleoli - Post-reduction X-rays **Step 4: Documentation** - Time of injury and time of reduction - Pre- and post-reduction neurovascular status - Quality of reduction on X-ray - Skin condition > **Consultant Tip:** Reduction under sedation in ED saves skin and cartilage. Don't delay for imaging if clinical deformity is obvious. The "wrinkle test" positive post-reduction indicates improved perfusion. number={3} question="What is your definitive surgical plan for this injury?" > **Surgical Strategy for Trimalleolar Fracture:** **Timing:** - Definitive surgery when soft tissues allow - "Wrinkle test" positive (indicates skin can tolerate surgery) - Usually 5-14 days post-injury - May use spanning external fixator if unstable and soft tissues poor **Surgical Approach and Sequence:** | Order | Structure | Approach | Fixation | |-------|-----------|----------|----------| | 1 | Posterior malleolus | Posterolateral (prone/lateral) | Lag screws ± antiglide plate | | 2 | Fibula | Lateral (direct) | Lag screw + neutralisation plate | | 3 | Medial malleolus | Medial (direct) | Two 4.0mm partially threaded screws | | 4 | Syndesmosis | Stress test intraoperatively | Suture button or screws if unstable | **Posterior Malleolus Decision:** | Indication for Fixation | Rationale | |-------------------------|-----------| | Fragment >25% of articular surface | ✓ (this patient) | | Step >2mm | Incongruity leads to arthritis | | Residual posterior subluxation | Syndesmotic stabiliser | | Large fragment amenable to fixation | Better syndesmotic stability | **Syndesmosis Assessment:** - External rotation stress test under fluoroscopy - Cotton test (lateral translation of fibula) - If medial clear space >4mm or tibiofibular clear space >5mm → fix syndesmosis **Fibula Fixation Options:** | Option | Indication | |--------|------------| | Posterolateral antiglide plate | Oblique fractures, less soft tissue stripping | | Lateral neutralisation plate | Standard approach | | Lag screw alone | Simple oblique pattern, good bone quality | > **Consultant Tip:** Fix posterior malleolus first via posterolateral approach (prone). This often reduces syndesmotic stability issues and may eliminate need for syndesmotic fixation. **Soft Tissue Assessment:** | Finding | Management | |---------|------------| | Fracture blisters | Wait for re-epithelialisation (7-10 days) | | Severe swelling | Delay until "wrinkle sign" positive | | Open wound | Debridement within 6 hours, provisional stabilisation | | Compartment syndrome | Fasciotomy | | Tented skin | Immediate reduction; if skin breaks down, treat as open | **Wrinkle Test:** - Gently pinch skin over anterior ankle - If skin wrinkles → soft tissues ready for surgery - If skin stays taut → wait longer **Indications for External Fixation (Temporary):** | Indication | Rationale | |------------|-----------| | Poor soft tissues | Bridge to definitive surgery | | Unstable after reduction | Maintain reduction | | Polytrauma | Damage control | | Open fracture with contamination | Allow soft tissue management | **External Fixator Technique:** - Delta frame configuration - Pin in anteromedial tibia (proximal) - Pin in calcaneus or first metatarsal (depending on injury) - Span ankle in neutral position **Fracture Blister Management:** - Serous blisters: aspirate, leave roof intact - Blood blisters: leave intact, mark boundaries - Both indicate significant soft tissue injury - Incision planning: avoid blisters, may need alternative approaches > **Consultant Tip:** The biggest mistake is rushing to surgery with compromised soft tissues. A wound complication turns a routine fracture into a disaster. Be patient - the bone will wait. **Posterolateral Approach to Posterior Malleolus:** **Positioning:** - Prone or lateral decubitus position - Bump under ipsilateral hip if lateral **Incision:** - Between lateral border of Achilles tendon and peroneal tendons - Approximately 10-12cm centred on fracture - Can extend distally to fix fibula through same approach **Internervous Plane:** - Between sural nerve territory and tibial nerve territory - Protect sural nerve (lateral) - Protect peroneal tendons (anterior) **Deep Dissection:** - Incise deep fascia - Retract peroneal tendons anteriorly - FHL muscle belly visible - retract medially - Posterior tibial surface exposed **Fixation Technique:** | Step | Detail | |------|--------| | 1 | Identify and reduce posterior malleolus fragment | | 2 | Provisional K-wire fixation | | 3 | Definitive fixation with antiglide plate (one-third tubular or LCP) | | 4 | Alternative: 3.5mm lag screws anterior-to-posterior (percutaneous) | | 5 | Fluoroscopic confirmation of reduction and screw position | **Advantages of Posterolateral Approach:** - Direct visualisation of articular reduction - Addresses posterior tibial fracture AND fibula through same incision - Can assess syndesmosis directly - Reduces incision load on vulnerable medial skin **Fibula from Same Approach:** - Extend incision proximally - Plate applied posterolaterally (antiglide principle) - Lag screw across fracture, plate neutralises > **Consultant Tip:** Prone positioning gives excellent visualisation of the posterior malleolus. Fixing posterior malleolus often stabilises syndesmosis without needing additional fixation. **Outcomes:** | Outcome | Percentage | |---------|------------| | Good/Excellent functional result | 60-75% | | Post-traumatic arthritis at 10 years | 30-40% | | Syndesmotic malreduction | 10-15% | | Return to pre-injury activity level | 50-70% | **Factors Affecting Outcome:** | Factor | Impact | |--------|--------| | Quality of reduction (anatomic) | Most important for outcome | | Posterior malleolus involvement | Higher arthritis rate | | Syndesmotic injury severity | Worse outcomes | | Age | Older patients do worse | | Associated cartilage injury | Worse outcomes | | Soft tissue damage | Affects rehabilitation | **Complications:** | Complication | Prevention/Management | |--------------|----------------------| | **Wound dehiscence** | Respect soft tissues, delay surgery if needed | | **Infection** | Prophylactic antibiotics, meticulous technique | | **Malunion** | Anatomic reduction, adequate fixation | | **Syndesmotic malreduction** | Intraoperative assessment, stress testing | | **Post-traumatic arthritis** | Cannot always prevent; may need fusion/replacement | | **Hardware prominence** | Consider removal at 12-18 months if symptomatic | | **Stiffness** | Early mobilisation, physiotherapy | | **Deep vein thrombosis** | Mechanical and chemical prophylaxis | **Syndesmotic Malreduction:** - Most common cause of poor outcome - Fibula too short, rotated, or translated - CT scan if any concern post-operatively - May need revision if significant malreduction **Long-term:** - Annual review for first 2 years - May develop symptomatic arthritis years later - Options: ankle arthrodesis or total ankle replacement > **Consultant Tip:** Anatomic reduction is everything. A 1mm lateral shift of talus reduces tibiotalar contact area by 42%. Syndesmotic malreduction is underdiagnosed - get post-op CT if concerned. --- ## Key Teaching Points ### Pattern Recognition **This pattern suggests Ankle Fracture-Dislocation Emergency:** - Fall mechanism with immediate deformity - Visible displacement of foot relative to leg - Tented or blanching skin (especially medially) - Diminished or absent pulses - Progressive swelling and ecchymosis **Lauge-Hansen Classification Overview:** | Mechanism | Foot Position | Force Direction | Pattern | |-----------|---------------|-----------------|---------| | **SER (Supination-External Rotation)** | Supinated | External rotation | Most common (60-70%), spiral fibula | | **SAD (Supination-Adduction)** | Supinated | Adduction | Transverse fibula below syndesmosis | | **PER (Pronation-External Rotation)** | Pronated | External rotation | High fibula fracture, syndesmosis injury | | **PAB (Pronation-Abduction)** | Pronated | Abduction | Bending fibula fracture | ### Critical Management Points 1. **Reduce immediately** - tented skin and diminished pulses are emergencies 2. **Document neurovascular status** - before AND after reduction 3. **Respect soft tissues** - delay surgery for swelling/blisters 4. **Fix posterior malleolus** - if >25% articular surface or step >2mm 5. **Assess syndesmosis** - stress test intraoperatively 6. **Anatomic reduction** - 1mm shift = 42% contact area loss --- ## Common Examiner Follow-ups **Q: "How do you assess syndesmotic stability intraoperatively?"** Syndesmotic assessment: 1. **External rotation stress test** - apply external rotation force to foot while holding leg fixed; observe tibiofibular widening on fluoroscopy 2. **Cotton test** - lateral translation of fibula with bone hook; >2mm translation suggests instability 3. **Compare to contralateral** - if available Fix syndesmosis if: - Medial clear space >4mm - Tibiofibular clear space >5mm on mortise view - Cotton test positive - Residual instability despite anatomic fracture fixation --- **Q: "What are the options for syndesmotic fixation?"** | Method | Advantages | Disadvantages | |--------|------------|---------------| | **Screws (3.5-4.5mm)** | Familiar, strong | May need removal, may break | | **Suture button** | Preserves physiologic motion, no removal needed | Learning curve, more expensive | | **Multiple screws** | More stable | More hardware complications | Current evidence (SynFix trial) suggests equivalent outcomes between screws and suture buttons. Suture buttons may have lower reoperation rate. --- **Q: "When would you consider non-operative management of an ankle fracture?"** Non-operative indications: - Stable, undisplaced fracture - Weber A (below syndesmosis) without medial injury - Isolated medial malleolus with no lateral or syndesmotic instability - Non-ambulatory patient - Severe medical comorbidities precluding surgery Weight-bearing in boot or cast with serial X-rays to confirm no displacement. --- **Q: "What is the significance of fibula length and rotation?"** Fibula length and rotation are critical because: - Fibula is key to mortise stability - Shortening allows lateral talar shift - Malrotation (usually external) widens mortise posteriorly - 1mm lateral talar shift = 42% reduction in tibiotalar contact area - Even small malreduction leads to eccentric loading and arthritis Assess on post-op X-ray and CT if concerned. --- ## Related Topics - Ankle Fractures (Weber Classification) - Syndesmotic Injuries - Open Fractures - External Fixation Techniques - Post-Traumatic Ankle Arthritis - Ankle Arthrodesis