import { ComparisonTable, ContentSection, EvidenceCard, ExamCheatSheet, ExamPearl, ExamWarning, InfoCard, InfoCardGrid, MedicalImage, MnemonicCard, OnePagerSummary, SafetyAlert, Tab, Tabs, Timeline, TimelineItem, VivaScenario, VivaScenarioSection } from '@/components/mdx' {/* SECTION 1: ONE-PAGER SUMMARY */} {/* SECTION 2: EXAM WARNING */} The **posterolateral approach requires prone positioning**. Cannot be done supine. Patient must be stable for prone position (no spinal injury, cardiovascular stability). Allows excellent visualization of the posterolateral tibial plateau. The **common peroneal nerve (CPN)** wraps around the fibular neck 1-2cm distal to fibular head. Must be identified early and protected. Injury causes foot drop and severe permanent disability. Use gentle retraction, no metal retractors on nerve. The **posterolateral fragment displaces posteriorly** under axial load. A **buttress plate** must be placed on the posterior surface to prevent re-displacement. Use contoured 3.5mm or locking plate. Screws directed anteriorly. **Bicondylar fractures (Schatzker V/VI)** often require **combined approaches**. PL approach for posterolateral fragment, anterolateral or posteromedial for other columns. Plan for two-stage positioning if needed. {/* SECTION 3: MNEMONICS */} The **posterolateral approach to the tibia** provides access to posterolateral tibial plateau fragments, which occur in **15-20% of tibial plateau fractures** and cannot be adequately visualized or stabilized through standard anterolateral approaches. **Prone positioning is mandatory** for true posterolateral access, with the incision placed lateral to the fibular head between peroneus longus and soleus. The **common peroneal nerve (CPN)** is the critical at-risk structure, wrapping around the fibular neck **1-2cm distal to the fibular head**—it must be identified early and protected throughout. A **buttress plate** placed on the posterolateral tibial surface prevents posterior displacement under axial loading. Bicondylar fractures (Schatzker V/VI) often require **combined approaches** with staged positioning. {/* SECTION 4: INDICATIONS */} **Primary Indications:** - **Posterolateral tibial plateau fractures** (isolated PL column) - **Schatzker II fractures** with significant posterolateral split-depression - **Bicondylar fractures (V/VI)** requiring posterolateral column fixation - **Revision surgery** for posterolateral fragment malunion **Why This Approach is Chosen:** The posterolateral tibial plateau is inaccessible from standard anterolateral approaches. The tibial plateau slopes posteriorly approximately 10 degrees, and posterolateral fragments displace posteriorly under axial load. Only a posterolateral approach allows direct buttress plating of this fragment. **Contraindications:** - Medical unfitness for prone position (spinal cord injury, recent MI) - Active infection of skin over approach - Severe soft tissue compromise posteriorly (may need delay) - Isolated anterior/medial fractures (use appropriate alternative approach) **Alternative Approaches:** - **Anterolateral approach**: For lateral plateau split/depression without PL fragment - **Posteromedial approach**: For medial plateau or posteromedial fragments - **Extended lateral with fibular osteotomy**: When combined AL and PL access needed - **Anteromedial approach**: For medial plateau fractures {/* SECTION 5: ANATOMY */} **Posterolateral Approach to the Tibia** provides direct access to the posterolateral tibial plateau for fractures that cannot be adequately visualized or fixed through standard anterolateral approaches. **Key Characteristics:** - Requires prone or lateral decubitus positioning - Common peroneal nerve (CPN) is the critical at-risk structure - Enables buttress plating of posteriorly displacing fragments - Often used in combination with other approaches for complex fractures **Why This Approach Matters:** - 15-20% of tibial plateau fractures involve posterolateral fragments - PL fragments missed on plain radiographs in up to 20% of cases - Cannot buttress PL fragments from anterolateral approach - Malreduction leads to posterior subluxation and early arthritis **Exam Relevance:** - High-yield surgical approach for Operative Surgery station - CPN protection is a classic examiner question {/* NumberHighlight removed */} **Bony Anatomy:** The posterolateral tibial plateau forms part of the lateral tibial condyle. The tibial plateau has an inherent 7-10 degree posterior slope. The posterolateral corner is the least supported region, making it vulnerable to split-depression fractures with axial loading combined with valgus stress. **Muscular Layers:** | Layer | Muscle | Nerve Supply | Action | |-------|--------|--------------|--------| | Superficial | Biceps femoris | Sciatic (tibial + CPN) | Knee flexion, lateral rotation | | Lateral compartment | Peroneus longus | Superficial peroneal | Plantar flexion, eversion | | Lateral compartment | Peroneus brevis | Superficial peroneal | Eversion | | Posterior superficial | Gastrocnemius (lateral head) | Tibial | Knee flexion, plantarflexion | | Posterior deep | Soleus | Tibial | Plantarflexion | **Neurovascular Anatomy:** | Structure | Location | Clinical Significance | |-----------|----------|----------------------| | Common peroneal nerve | Wraps around fibular neck 1-2cm distal to head | MOST IMPORTANT - injury causes foot drop | | Superficial peroneal nerve | Between peroneus longus and brevis | Supplies lateral compartment muscles | | Deep peroneal nerve | Deep in anterior compartment | Not at risk in this approach | | Peroneal artery | Deep in posterior compartment | May be encountered with deep dissection | | Anterior tibial artery | Through interosseous membrane | Protected by anterior compartment | **Three-Column Classification of Tibial Plateau:** Understanding which column is fractured guides approach selection: - **Lateral column**: Anterolateral approach - **Medial column**: Anteromedial or posteromedial approach - **Posterior column (PL + PM)**: Posterolateral and/or posteromedial approach {/* SECTION 6: INTERNERVOUS PLANE */} **Deep Internervous Plane:** - **Between**: Peroneus longus (superficial peroneal nerve) laterally and Soleus (tibial nerve) medially/posteriorly - **Clinical relevance**: This is the safe interval between the two muscle groups innervated by different nerves **Superficial Dissection:** There is no true internervous plane in the superficial dissection. The approach passes through the lateral compartment which is supplied entirely by the superficial peroneal nerve. However, the muscles are retracted rather than divided, minimizing denervation risk. Unlike hip approaches where the internervous plane is between two major muscles, the tibial posterolateral approach relies on **inter-compartmental dissection** between the lateral and posterior compartments. The key is to stay anterior to the soleus while protecting the CPN which runs between the two heads of peroneus longus. **Structures at Risk in Each Layer:** | Layer | Structure | Protection Strategy | |-------|-----------|-------------------| | Superficial | Common peroneal nerve | Identify early, tape sling, no metal retractors | | Deep | Peroneal vessels | Ligate small branches, preserve major vessels | | Deep | Popliteal vessels | Should not be encountered if dissection plane correct | | Articular | Lateral meniscus | Incise capsule carefully, protect during reduction | {/* SECTION 7: POSITIONING AND PATIENT SETUP */} **Position: Prone on Radiolucent Table** **Pre-positioning Checklist:** - Confirm patient stable for prone position (anesthetic assessment) - Padding for all pressure points (face, chest, pelvis, patella, ankles) - Arms positioned safely (abducted less than 90 degrees, padded) - Radiolucent table confirmed - C-arm access verified from lateral aspect **Positioning Details:** - **Prone position** with chest rolls or Wilson frame - **Affected knee** slightly flexed over a bolster (relaxes CPN) - **Foot** overhanging end of table or supported - **Tourniquet** applied high on thigh if planned (consider tourniquet-free surgery) Prone positioning carries risks including facial swelling, brachial plexus injury, and compartment syndrome of the thigh. Limit operative time, ensure adequate padding, and document all protective measures taken. **Alternative Positioning:** - **Lateral decubitus** can be used with the affected side UP - Allows combination with anteromedial or anterolateral approaches without repositioning - Some exposure is sacrificed compared to true prone positioning {/* SECTION 8: SURFACE LANDMARKS */} **Key Bony Landmarks:** - **Fibular head** - palpable prominence lateral to knee - **Biceps femoris tendon** - inserts onto fibular head - **Lateral tibial plateau** - can palpate lateral joint line - **Gerdy's tubercle** - anterolateral tibial insertion of ITB **Key Soft Tissue Landmarks:** - **Common peroneal nerve** - can often be palpated wrapping around fibular neck - **Popliteal fossa** - defines posterior boundary - **Lateral gastrocnemius head** - marks posterior musculature **Incision Planning:** - Longitudinal incision **behind the fibular head** extending distally - Length: 8-12cm depending on exposure required - Stays **anterior to the biceps tendon** proximally - Curves around fibular head following the lateral fibular border {/* SECTION 9: SURGICAL TECHNIQUE */} ### Three-Column Classification (Luo) ### Schatzker Classification Relevance - **Type II**: Lateral split-depression - may have PL component - **Type V**: Bicondylar - often requires combined approaches - **Type VI**: Bicondylar with metaphyseal-diaphyseal dissociation - frequently has posterior fragments ### Approach Variants ### Fragment Morphology Classification - **Split**: Vertical fracture line - direct reduction and buttress - **Depression**: Impacted articular surface - requires elevation and grafting - **Split-depression**: Combination - most common pattern ### History - **Mechanism**: High-energy (MVA, fall from height) vs low-energy (elderly, osteoporotic) - **Timing of injury**: Affects soft tissue planning - **Associated injuries**: Polytrauma assessment - **Medical fitness**: Suitability for prone positioning ### Examination **Neurovascular Assessment (Critical):** - **Dorsalis pedis and posterior tibial pulses**: Document bilateral comparison - **Ankle dorsiflexion**: Tests CPN function pre-operatively (baseline) - **Toe extension**: Deep peroneal nerve function - **First web space sensation**: Deep peroneal sensory **Soft Tissue Assessment:** - **Swelling**: Degree and circumference - **Blistering**: Serous vs hemorrhagic (hemorrhagic = deeper injury) - **Wrinkle test**: Positive indicates safe for surgery - **Skin condition**: Abrasions, lacerations, degloving ### Soft Tissue Timing Protocol **Immediate Surgery (within 24-48 hours):** - Open fractures - Vascular injury requiring repair - Compartment syndrome **Delayed Definitive Fixation (7-14 days):** - Significant swelling/blistering - Wait for wrinkle test positive - Use spanning external fixator for interim stability **Wrinkle Test Interpretation:** - Positive: Skin wrinkles when compressed - adequate dermal blood flow - Negative: Skin does not wrinkle - delay surgery Operating through compromised soft tissue increases infection risk from 2-5% to 20-30%. Always wait for soft tissue recovery unless emergent indication. ### Imaging Algorithm **Plain Radiographs (Initial):** - AP knee - assess overall alignment, fracture pattern - Lateral knee - identify posterior fragment displacement - Oblique views (internal and external rotation) - improve fragment visualization **CT Scan (Essential for ALL tibial plateau fractures):** - Axial, coronal, sagittal reconstructions - 3D reconstruction for surgical planning - Identifies posterolateral fragments missed in up to 20% on plain films - Quantifies articular depression and fragment size **Every tibial plateau fracture** being considered for operative treatment requires CT scanning. Posterolateral fragments are commonly missed on plain radiographs and change the surgical approach. ### CT-Based Three-Column Analysis **Systematic CT Review:** 1. **Axial cuts at joint line**: Identify all column involvement 2. **Coronal reconstructions**: Assess articular depression depth 3. **Sagittal reconstructions**: Evaluate posterior slope and fragment displacement 4. **3D surface rendering**: Overall fracture morphology visualization **Fragment Size Assessment:** - Small PL fragment (less than 25% of plateau): May accept some malreduction - Large PL fragment (greater than 25%): Requires anatomic reduction - Split-depression: Measure depth of depression (greater than 5mm typically operative) ### Additional Investigations **MRI (Selective Use):** - Ligamentous injury assessment if suspected - Meniscal pathology evaluation - Usually not required for surgical planning of fracture **Angiography/CTA:** - If vascular injury suspected (absent pulses, ABI less than 0.9) - High-energy injuries with knee dislocation component ### Non-Operative Management **Indications (Rare for PL fragments):** - Non-displaced or minimally displaced (less than 2mm step-off) - Low functional demand patient - Medical contraindications to surgery **Protocol:** - Hinged knee brace - Non-weight bearing 6-8 weeks - Early ROM exercises - Serial radiographs to monitor displacement ### Operative Management (Standard for PL Fragments) **Surgical Indications:** - Articular step-off greater than 2mm - Condylar widening greater than 5mm - Any instability in extension - Associated ligamentous injury requiring repair **Approach Selection Based on CT:** - Isolated PL fragment → Posterolateral approach - PL + PM fragments → Combined posterior approaches (prone) - PL + lateral column → Extended lateral or staged approaches - Bicondylar (Schatzker V/VI) → Multiple approaches, staged positioning ### Staged Management Protocol **Stage 1 (Acute, 0-48 hours):** - Closed reduction if subluxed - Spanning external fixator if unstable - Elevation, ice, soft tissue monitoring - DVT prophylaxis **Stage 2 (Definitive, 7-14 days):** - Wait for wrinkle test positive - CT-based surgical planning - Definitive ORIF through appropriate approach(es) ### Combined Approach Planning **Key Principle:** Fix posterior columns first (harder to access), then flip for anterior work if needed. **Step 1: Incision** Make a longitudinal incision starting at lateral joint line and extending distally along posterior border of fibula. Length 8-12cm depending on fracture extent. **Step 2: Superficial Dissection** Incise skin and subcutaneous tissue. Identify and protect the lateral sural cutaneous nerve if encountered. Incise fascia over lateral compartment. **Step 3: CPN Identification (CRITICAL)** The CPN emerges from behind the biceps femoris tendon. It wraps around the fibular neck 1-2cm distal to the fibular head. Identify it early before any retraction. Carefully trace its course. Place vessel loop or tape sling for gentle retraction. **Step 4: Deep Dissection** Develop plane between peroneus longus (anterior) and soleus (posterior). Retract peroneus longus anteriorly (CPN goes with it - protected). Retract soleus and gastrocnemius posteriorly. Subperiosteal dissection exposes posterolateral tibial plateau. **Articular Visualization:** Incise the posterolateral capsule if articular surface visualization needed. Protect the lateral meniscus carefully. Irrigate to visualize articular fragments clearly. **Fragment Reduction:** Use bone tamps to elevate depressed fragments. Reduce split fragments with pointed reduction clamps. Provisional K-wire fixation to maintain reduction during plate application. **Bone Graft:** Metaphyseal void after fragment elevation requires grafting. Options include cancellous autograft from same incision or distal femur, allograft, or bone substitute materials. **Fluoroscopy Confirmation:** Obtain AP, lateral, and oblique views to confirm articular reduction. Assess joint line restoration and posterior tibial slope. Accept less than 2mm articular step-off. **Plate Selection:** Use a 3.5mm T-plate, L-plate, or anatomic posterolateral tibial plateau plate. Choose locking or non-locking depending on bone quality. Contour carefully to match the posterior tibial surface. **Buttress Plate Placement:** Apply plate to the posterior tibial surface. Proximal screws capture the posterolateral fragment. Direct screws anteriorly and medially. Avoid intra-articular screw placement by checking under fluoroscopy. **Fixation Principles:** The buttress plate function prevents posterior displacement under load. Use at least 3-4 screws in the proximal fragment. Place distal screws in healthy diaphyseal bone for stable construct. **Irrigation:** Copious irrigation with normal saline. Check for any bleeding vessels and achieve meticulous hemostasis before closure. **Drain:** Consider drain placement based on surgeon preference. If used, exit the drain away from the CPN course. **Closure Layers:** Close the capsule if opened using absorbable suture. Close fascial layer with absorbable suture. Approximate subcutaneous tissue. Close skin with staples or interrupted sutures. **Post-operative Imaging:** Confirm reduction and fixation on fluoroscopy. Obtain full-length AP and lateral radiographs. Consider CT if any concern about articular reduction quality. {/* SECTION 10: STRUCTURES AT RISK */} **THE most important structure at risk.** Wraps around fibular neck 1-2cm distal to fibular head. Injury causes foot drop (loss of ankle dorsiflexion and toe extension). Prevention: early identification, gentle handling, vessel loop protection, no metal retractors. The **peroneal artery and veins** run deep in the posterior compartment. Usually not encountered with correct dissection plane. If damaged, ligate small branches; major vessel injury requires repair. Branch of popliteal artery at the joint line. May be encountered during capsular incision. Ligate if bleeding - does not require repair. At risk during capsular incision and articular surface visualization. Protect during reduction maneuvers. Peripheral tears can be repaired; body tears may need partial meniscectomy. **CPN Injury Management:** - If nerve identified as damaged intra-operatively: primary repair if transected - If neurapraxia suspected: observe, document, follow up closely - Post-operative foot drop: urgent EMG/NCS at 3 weeks, consider exploration if no recovery by 3 months {/* SECTION 11: EXTENSILE OPTIONS */} **Fibular Osteotomy:** - **Indication**: When standard PL approach does not provide adequate exposure - **Technique**: Oblique osteotomy of fibular neck from posterolateral to anteromedial - **CPN protection**: Must identify and protect nerve BEFORE osteotomy - **Fixation**: Repair with small plate or tension band at end of case - **Complication**: Fibular nonunion (5%), CPN injury (higher risk) **Proximal Extension:** - Can extend incision proximally along biceps femoris - Allows access to the posterolateral femoral condyle if needed - CPN becomes more superficial proximally - increased risk **Distal Extension:** - Extend distally along fibula for access to tibial diaphysis - Useful for fractures extending into shaft - Stay in same intermuscular plane **Combined Approaches:** For bicondylar fractures (Schatzker V/VI), often need: - Posterolateral approach (for PL fragment) - Plus anteromedial approach (for PM fragment) - Or anterolateral (for lateral plateau split) {/* SECTION 12: COMPLICATIONS */} **Intra-operative Complications:** | Complication | Prevention | Management | |--------------|------------|------------| | CPN injury | Early ID, gentle retraction, no metal retractors | Document, EMG at 3 weeks, explore if no recovery | | Articular malreduction | Good visualization, fluoroscopy, CT if concern | Accept less than 2mm step-off; redo if more | | Peroneal vessel injury | Stay in correct plane | Ligate small branches, repair major vessels | | Intra-articular hardware | Careful screw length measurement, fluoroscopy | Remove and replace with shorter screw | **Post-operative Complications:** | Complication | Incidence | Prevention | Treatment | |--------------|-----------|------------|-----------| | CPN palsy | 3-5% | Careful technique | Observe, AFO, explore if no recovery 3 months | | Infection | 2-5% | Antibiotics, soft tissue rest | Irrigation and debridement, antibiotic suppression or removal | | Post-traumatic OA | 20-40% | Anatomic reduction | Weight loss, analgesia, eventual TKA | | Nonunion/malunion | Under 5% | Bone graft, stable fixation | Revision ORIF or TKA | | DVT/PE | 2-5% | Chemoprophylaxis, early mobilization | Anticoagulation | CPN injury in tibial plateau surgery ranges from **3-20%** depending on approach and complexity. Posterolateral approaches have **higher risk** than anterolateral. Most injuries are neurapraxia that recover, but permanent foot drop occurs in 1-3% and is a devastating complication. {/* SECTION 13: POST-OPERATIVE CARE */} **Immediate Post-operative:** - Neurovascular check documenting **ankle dorsiflexion** (CPN function) - Wound inspection - Knee immobilizer or hinged brace for comfort - Elevate limb above heart level **Weight Bearing Protocol:** - **Non-weight bearing or touch weight bearing** for 6-12 weeks - Progression based on fracture healing and surgeon preference - Crutches or walker required **Range of Motion:** - CPM or early ROM exercises as pain allows - Goal: 0-90 degrees by 6 weeks - No resistance exercises until fracture healed **Follow-up Schedule:** - 2 weeks: Wound check, suture/staple removal - 6 weeks: Radiographs, assess healing, progress WB if appropriate - 12 weeks: Radiographs, confirm union, progress to full WB - 6 months: Final radiographs, functional assessment - 1 year: Clinical and radiographic review **DVT Prophylaxis:** - LMWH or aspirin per institutional protocol - Duration: Until mobile (minimum 2 weeks, often 4-6 weeks) {/* SECTION 14: EVIDENCE BASE */} ### Immediate Post-Operative (0-48 hours) **Critical Monitoring:** - **Neurovascular check every 2 hours** for first 24 hours - **Document ankle dorsiflexion** (CPN function) - compare to pre-op baseline - Monitor for compartment syndrome (pain, pallor, pulselessness, paresthesia) - Wound inspection at 24-48 hours **Positioning and Immobilization:** - Elevate limb above heart level - Knee immobilizer or hinged brace locked in extension - Ice packs around knee (not directly on surgical site) ### Weight Bearing Protocol - **Weeks 0-6**: Non-weight bearing or touch weight bearing - **Weeks 6-10**: Partial weight bearing (25-50%) - **Weeks 10-12**: Progressive to full weight bearing - **Progression criteria**: Radiographic evidence of healing, no pain with weight bearing ### Rehabilitation Phases **Phase 1 (Weeks 0-6): Protection** - NWB with crutches/walker - Passive ROM 0-90 degrees as tolerated - Quadriceps isometrics, ankle pumps - No active hamstring exercises (protect repair) **Phase 2 (Weeks 6-12): Early Motion** - Progressive weight bearing per radiographs - Active ROM exercises - Stationary bike when 90 degrees flexion achieved - Proprioceptive training begins **Phase 3 (Weeks 12+): Strengthening** - Full weight bearing - Closed-chain strengthening (squats, leg press) - Return to activities based on function - Full return to sport/work 6-12 months ### DVT Prophylaxis - LMWH or aspirin per institutional protocol - Duration: Until mobile (minimum 2 weeks, often 4-6 weeks) - Consider mechanical prophylaxis (IPC) while inpatient {/* NumberHighlight removed */} ### Functional Outcomes **Good Prognostic Factors:** - Anatomic articular reduction (less than 2mm step-off) - Young age and low energy mechanism - Isolated PL fragment (not bicondylar) - No associated ligament injury - Early ROM and rehabilitation **Poor Prognostic Factors:** - Articular step-off greater than 2mm - Bicondylar fractures (Schatzker V/VI) - Associated ligament/meniscal injury - High-energy mechanism - Delayed surgery due to soft tissue compromise ### Long-Term Outcomes by Fracture Type ### Complications Impact on Outcomes - **CPN injury**: 60% full recovery, 30% partial recovery, 10% permanent - **Infection**: Deep infection significantly worsens outcome - **Malreduction**: Each mm of step-off increases OA risk - **Stiffness**: Rarely limits function if greater than 90 degrees flexion achieved The single most important factor for good outcome is **anatomic articular reduction** - less than 2mm step-off. This is why CT scanning and appropriate approach selection (including posterolateral when indicated) are critical. {/* SECTION 15: MCQ POINTS */} **Q: What position is required for the posterolateral approach to the tibia?** A: **Prone position** is required. The posterolateral tibial plateau cannot be adequately exposed in the supine position. Lateral decubitus (affected side up) is an alternative that allows combination with other approaches. **Q: What is the most important structure at risk during the posterolateral approach?** A: The **common peroneal nerve (CPN)** is the most critical structure. It wraps around the fibular neck 1-2cm distal to the fibular head and is at risk during retraction. Injury causes foot drop. **Q: What is the deep internervous plane in the posterolateral approach?** A: Between **peroneus longus** (superficial peroneal nerve) and **soleus** (tibial nerve). This inter-compartmental plane allows access to the posterolateral tibia without denervating muscle. **Q: Why is a buttress plate required for posterolateral tibial plateau fractures?** A: The posterolateral fragment **displaces posteriorly under axial load**. A buttress plate on the posterior tibial surface prevents this displacement. An anterolateral plate cannot provide this buttress function. **Q: Why is CT scanning essential for tibial plateau fractures?** A: Posterolateral fragments are commonly **missed on plain radiographs**. CT defines the fracture morphology, identifies all fragments, and allows preoperative planning of approach selection. Up to 20% of tibial plateau fractures have posterolateral fragments requiring direct fixation. **Q: When would you use combined approaches for tibial plateau fractures?** A: **Bicondylar fractures (Schatzker V/VI)** often require combined approaches. Use posterolateral approach for PL fragments plus anteromedial or anterolateral for other columns. May require staged positioning. {/* SECTION 16: AUSTRALIAN CONTEXT */} Tibial plateau fractures are commonly managed at major trauma centers throughout Australia. The three-column concept is widely adopted, and CT scanning is now standard for operative planning. Australian trauma surgeons increasingly utilize posterior approaches when posterolateral or posteromedial fragments are identified. The Royal Australasian College of Surgeons (RACS) trauma committees emphasize the importance of preoperative planning and approach selection based on CT findings. Early soft tissue assessment is critical given the high-energy mechanism in many Australian cases (motor vehicle accidents, agricultural injuries). Consent in Australia should include discussion of CPN injury risk (3-5%), infection risk (2-5%), post-traumatic arthritis (20-40%), and the possibility of requiring total knee replacement in the future if significant articular cartilage damage has occurred. For the Orthopaedic Operative Surgery station, you must be able to describe the posterolateral approach systematically: prone positioning, CPN identification and protection, the internervous plane, and buttress plate placement. Know the evidence for CT scanning of all tibial plateau fractures and when combined approaches are needed. {/* SECTION 17: VIVA SCENARIOS */}

Assessment: Full trauma assessment following ATLS principles. Detailed history of mechanism. Clinical examination for knee stability, neurovascular status (especially ankle dorsiflexion), and soft tissue condition. Imaging with plain radiographs (AP, lateral, oblique) followed by CT with 3D reconstruction.

Surgical Planning: CT confirms posterolateral fragment - requires posterolateral approach as cannot buttress from anterolateral. Patient must be suitable for prone positioning. Assess soft tissue - wait for wrinkle test if blistering present.

Surgical Approach: Prone position on radiolucent table. Longitudinal incision posterior to fibula. Identify and protect CPN early - vessel loop. Develop plane between peroneus longus (anteriorly) and soleus (posteriorly). Expose posterolateral tibial plateau.

Reduction and Fixation: Elevate depressed fragments with bone tamp. Reduce split component with clamps. Bone graft metaphyseal void. Apply buttress plate to posterior tibial surface with screws directed anteriorly. Confirm reduction on fluoroscopy - accept less than 2mm step-off.

Post-operative: Document CPN function. NWB for 6-12 weeks. Early ROM. DVT prophylaxis.

} keyPoints={[ "Confirm fracture morphology on CT - posterolateral fragment identified", "Posterolateral approach required - cannot fix from anterior", "Prone positioning essential for true PL access", "CPN identification and protection is paramount", "Develop plane between peroneus longus and soleus", "Elevate depressed fragments, bone graft void", "Buttress plate on posterior tibial surface", "Aim for less than 2mm articular step-off" ]} traps={[ "Attempting to fix from anterolateral approach (cannot buttress PL fragment)", "Not ordering CT preoperatively (misses PL fragments)", "Forgetting CPN protection (most important structure at risk)", "Not mentioning buttress plate principle" ]} followUp={[ "What if the patient also has a posteromedial fragment?", "How would you manage a CPN palsy post-operatively?", "What is the long-term prognosis for this fracture?" ]} />

Immediate Assessment: Full motor examination - test ankle dorsiflexion (deep peroneal nerve), toe extension (deep peroneal), and foot eversion (superficial peroneal). Sensory examination - first web space (deep peroneal) and lateral leg/dorsum of foot (superficial peroneal). Document findings accurately.

Exclude Other Causes: Remove dressings - check for constriction. Assess for compartment syndrome (pain with passive stretch, tense compartments). Review intra-operative events - was nerve visualized, any inadvertent injury noted?

Most Likely Diagnosis: Common peroneal nerve neurapraxia from traction or compression during retraction. CPN is particularly vulnerable as it wraps around the fibular neck with limited mobility.

Initial Management: Provide ankle-foot orthosis (AFO) to maintain ankle in neutral and prevent equinus contracture. Counsel patient about prognosis - most neurapraxias recover within 3-6 months. Document thoroughly including discussion with patient.

Follow-up Plan: EMG/NCS at 3 weeks post-injury (allows time for Wallerian degeneration if axonal injury). If no clinical or EMG recovery by 3 months, consider nerve exploration. Tendon transfers (tibialis posterior to dorsum) are an option for permanent foot drop.

} keyPoints={[ "Diagnosis: likely common peroneal nerve injury", "Mechanism: traction, compression from retractors, or direct injury", "Immediate assessment: full motor and sensory exam of the foot", "Check for correctable causes (tight dressing, compartment syndrome)", "Most CPN injuries are neurapraxia - will recover", "AFO to prevent equinus contracture", "EMG/NCS at 3 weeks to assess severity", "Consider exploration if no recovery by 3 months" ]} traps={[ "Assuming it will resolve without investigation", "Promising full recovery (60% recover, not 100%)", "Not providing AFO for function during recovery", "Not documenting the injury and discussing prognosis with patient" ]} followUp={[ "What would you see on EMG if this were neurapraxia versus axonotmesis?", "When would you consider nerve exploration?", "What are the long-term options if permanent foot drop?" ]} />

CT Analysis: Use three-column concept to analyze fracture. Identify: lateral column involvement, medial column involvement, and posterior column (subdivided into posteromedial and posterolateral). This Schatzker VI with PM and PL fragments requires at least two approaches.

Approach Selection: Posterolateral approach for PL fragment (prone, lateral to fibula, buttress plate posteriorly). Posteromedial approach for PM fragment (prone or supine with leg externally rotated, medial to gastrocnemius, buttress plate posteromedially). If significant anterior column involvement, add anterolateral approach.

Positioning Strategy - Option 1: Start prone - allows access to both PL and PM fragments through separate incisions. Can address both posterior columns in one position. May need to flip to supine if anterolateral approach required.

Positioning Strategy - Option 2: Lateral decubitus with affected side up - allows access to PM and PL without repositioning, and can also access anterolateral. Some surgeons prefer this for combined approaches.

Sequence: Generally fix posterior columns first as they are more difficult to access. Then flip to supine for anterior work if needed. Bone graft all metaphyseal voids. Aim for less than 2mm articular step-off on all columns.

} keyPoints={[ "CT-based planning essential - define all columns involved", "Three-column concept guides approach selection", "Posterolateral approach for PL fragment", "Posteromedial approach for PM fragment", "Consider anterolateral for lateral column if needed", "Positioning strategy: prone first (PL and PM), then supine (anterior) OR lateral decubitus for all", "Usually fix posterior columns first, then anterior", "Bone graft metaphyseal voids" ]} traps={[ "Trying to fix everything from one approach", "Not considering positioning logistics for combined approaches", "Forgetting to bone graft the metaphyseal void", "Not achieving anatomic reduction (less than 2mm step-off)" ]} followUp={[ "How do you decide the order of approaches?", "What are the soft tissue considerations for timing of surgery?", "When would you use a fibular osteotomy?" ]} />

Posterolateral Approach: Targets the posterolateral tibial plateau. Positioning: prone or lateral decubitus with affected side up. Incision: posterior to fibula. Internervous plane: between peroneus longus (superficial peroneal nerve) and soleus (tibial nerve). Key structure at risk: COMMON PERONEAL NERVE - injury causes foot drop (motor loss).

Posteromedial Approach: Targets the posteromedial tibial plateau. Positioning: prone, lateral, or supine with leg externally rotated (knee flexed). Incision: posteromedial leg, along medial border of gastrocnemius. Internervous plane: between medial gastrocnemius (tibial nerve) and semimembranosus/pes anserinus (tibial nerve branches). Key structure at risk: SAPHENOUS NERVE - sensory only.

Safety Comparison: The posteromedial approach is generally considered safer because the nerve at risk (saphenous) is sensory only, whereas the posterolateral approach risks the CPN which causes significant motor deficit (foot drop) if injured.

Common Principle: Both approaches require buttress plate placement on the posterior tibial surface to prevent posterior fragment displacement under axial loading.

When to Use Both: Bicondylar fractures (Schatzker V/VI) often have both PM and PL fragments requiring both approaches for complete fixation.

} keyPoints={[ "PL approach: prone or lateral, targets posterolateral plateau", "PM approach: prone, lateral, or supine with leg externally rotated", "PL approach: CPN at risk (motor - foot drop)", "PM approach: saphenous nerve at risk (sensory only)", "PL interval: peroneus longus / soleus", "PM interval: medial gastrocnemius / soleus", "PM approach generally considered safer (sensory nerve only)", "Both require buttress plating principle" ]} traps={[ "Confusing which nerve is at risk in each approach", "Not knowing the internervous planes", "Saying one approach can access both fragments", "Forgetting positioning requirements" ]} followUp={[ "When would you use both approaches together?", "How do you protect the CPN in the posterolateral approach?", "What is the prognosis of saphenous nerve injury?" ]} />

Significance of Soft Tissue Injury: Blistering and significant swelling indicate high-energy injury mechanism. The anteromedial tibial skin is at highest risk (subcutaneous bone, poor vascularity). Operating through compromised skin dramatically increases infection risk (up to 20-30% with poor soft tissue timing).

Soft Tissue Assessment: Examine the entire circumference of the knee and proximal tibia. Differentiate serous blisters (intact epidermis) from hemorrhagic blisters (deeper injury). The posterolateral skin over the fibula may be spared even with significant anteromedial swelling.

Timing Decision: Apply the wrinkle test - gently compress skin to assess for wrinkling which indicates adequate dermal blood flow for healing. Typically need to wait 7-14 days for soft tissue recovery. Wait until swelling resolved, blisters re-epithelialized, and wrinkle test positive.

Interim Management: If fracture unstable, apply spanning external fixator (temporary knee-spanning construct). Elevate limb above heart level. Splint for comfort. Serial neurovascular checks. Counsel patient about delayed definitive surgery and reasons.

Staged Surgery Option: If posterolateral skin is healthy but anterior skin compromised, may proceed with posterolateral approach first to address PL fragment, then delay anterolateral approach until anterior soft tissue recovery. This allows partial stabilization while awaiting optimal conditions for complete fixation.

} keyPoints={[ "Blisters and swelling indicate high-energy injury", "Anteromedial skin most at risk (subcutaneous bone)", "Posterolateral skin usually less compromised", "Delay surgery until wrinkle test positive (7-14 days)", "Interim management: spanning external fixator if unstable", "Elevation, ice, splinting while waiting", "May be able to proceed with PL approach if posterior skin OK", "Could stage surgery: PL first, AL/AM later when anterior skin recovered" ]} traps={[ "Operating through compromised skin (high infection risk)", "Not using external fixator for interim stability", "Ignoring the wrinkle test", "Not counseling patient about delayed surgery and reasons" ]} followUp={[ "What is the wrinkle test?", "How long would you typically wait for soft tissue recovery?", "What are the signs of compartment syndrome to watch for?" ]} /> {/* SECTION 18: EXAM CHEAT SHEET */}

Tibia Posterolateral Approach

Tibia Posterolateral Approach