import { OnePagerSummary, ContentSection, ExamWarning, InfoCardGrid, InfoCard, EvidenceCard, ComparisonTable, VivaScenario, MnemonicCard, ExamCheatSheet, Tab, Tabs } from '@/components/mdx' ### Primary Indications - Trauma **Posteromedial Tibial Plateau Fractures** - Schatzker Type IV: Medial plateau fracture with posteromedial extension - Coronal split fractures involving posterior medial plateau - Failed reduction via anteromedial approach (posterior fragment not accessible) - Bicondylar fractures (Schatzker V, VI) with significant posteromedial component **Posteromedial Corner Injuries** - Avulsion fractures of semimembranosus insertion - Posterior oblique ligament (POL) repair - Posteromedial capsular injuries - Combined ligamentous reconstructions ### Secondary Indications **Meniscal Pathology** - Posterior medial meniscus root tear (open repair) - Peripheral posterior horn tear requiring inside-out repair - Meniscus transplantation (medial) **Vascular Access** - Popliteal vessel exploration (in combination with vascular surgery) - Repair of iatrogenic popliteal vessel injury ### Contraindications **Absolute** - Active infection overlying incision site - Severe vascular compromise (requires vascular surgery first) **Relative** - Severe peripheral vascular disease (high vessel injury risk) - Severe soft tissue injury (compartment syndrome, extensive degloving) - Obesity (BMI greater than 40) - very difficult exposure Posteromedial approach is HIGH-RISK due to proximity of popliteal vessels - always have vascular surgery backup available, and never drill or place screws without absolute certainty of trajectory. Most common error is anterior cortex penetration injuring popliteal artery. ### Clinical Assessment **History and Mechanism** - High-energy trauma pattern (MVA, fall from height, pedestrian struck) - Varus force mechanism (medial plateau fractures) - Combined injury patterns - Vascular injury symptoms (pain, pallor, pulselessness) **Physical Examination - CRITICAL** - **Neurovascular exam MANDATORY**: - Dorsalis pedis and posterior tibial pulses - Capillary refill - Ankle-brachial index (ABI) if pulses diminished - Saphenous nerve function (sensation medial leg/foot) - Compartment assessment (high-energy injuries) - Soft tissue envelope (open vs closed) - Knee stability (medial, posterior) ### Imaging Protocol **Standard Radiographs** - AP and lateral knee - Oblique views (posteromedial plateau visualization) - Traction views if comminuted **CT Imaging - MANDATORY** - Fine-cut (1mm) CT with 3D reconstruction - **Critical assessments**: - Fracture pattern (coronal split, depression) - Posterior extension (need posteromedial approach?) - Articular step-off and comminution - Safe screw corridors **CT Angiography - Consider If** - Diminished pulses - High-energy mechanism - Severe displacement - Identifies vascular injury before surgery **MRI - Selected Cases** - Ligamentous injury assessment (POL, MCL, PCL) - Meniscal pathology evaluation ### Surgical Planning **Approach Selection** - Isolated posteromedial fracture: posteromedial alone (rare) - Bicondylar fracture: dual approach (anteromedial + posteromedial, or anterolateral + posteromedial) - Timing: staged vs same-day dual approach **Fixation Strategy** - Posteromedial buttress plate (most common) - Lag screws from posteromedial to anterolateral - Combined with anterior plate for bicondylar patterns **Team Planning** - Vascular surgery on standby (popliteal vessel risk) - Extensile exposure preparation (may need to extend) ### Standard Equipment **Basic Instruments** - Trauma set with heavy retractors - Self-retaining retractors (bent Hohmann) - Periosteal elevators - Pointed reduction forceps - Electrocautery **Fracture Fixation** - Posteromedial tibial plateau plates (anatomic pre-contour) - 3.5mm cortical and canculated screws - 4.0mm and 6.5mm cannulated screws (lag screw options) - K-wires (provisional fixation) - Bone graft instruments (if needed) **Vascular Instruments - HAVE AVAILABLE** - Vascular clamps - Vessel loops - Fine vascular instruments ### Fluoroscopy **Essential - Large C-Arm** - Must obtain good AP, lateral, and oblique views - Difficult in prone position (limited angulation) - Radiolucent table critical ### Option 1: Prone Positioning **Advantages** - Direct access to posteromedial corner - Easier dissection (gravity-assisted) - Good for isolated posteromedial fractures **Disadvantages** - Cannot combine with anterior approach in same sitting - Fluoroscopy more difficult - Patient repositioning needed if conversion to anterior **Positioning Technique** - Standard prone on chest rolls or Wilson frame - Leg slightly internally rotated - Bump under distal thigh (knee flexion 20-30 degrees) - Ensure adequate padding ### Option 2: Supine with Leg Hanging **Advantages** - Allows staged anterior and posterior approaches same day - Easier fluoroscopy - Easier conversion to anterior if needed **Disadvantages** - Gravity works against you (medial structures sag away) - Requires assistant to hold leg - Cramped working space **Positioning Technique** - Supine on OR table - Leg hanging off side of table at knee level - Knee flexed 90 degrees - Assistant holds leg or use leg holder ### Tourniquet Considerations **Advantages** - Bloodless field for dissection - Better visualization of posterior capsule **Disadvantages** - Can miss vascular injury (don't deflate until before closure) - Limits working time (2 hours max) **Recommendation** - Use tourniquet but deflate periodically to check for bleeding - Have low threshold to deflate if vascular injury suspected **Critical principle**: Popliteal vessels are millimeters from surgical field (1-2cm anterior to posteromedial tibial plateau) **Assume vascular injury until proven otherwise**: - ANY unexpected bleeding during posteromedial approach - Pulsatile bleeding - Expanding hematoma - Hemodynamic instability **Immediate management**: 1. **Direct pressure** (do NOT clamp blindly - risks nerve injury) 2. **Call vascular surgery IMMEDIATELY** (do not hesitate - limb-threatening emergency) 3. Tourniquet inflation if not already inflated 4. Proximal/distal control of popliteal artery if accessible **Do NOT delay** vascular surgery consultation - popliteal artery injury requires immediate repair (ischemia time critical, limb loss risk 10-15% if delayed >6 hours) ### Bony Landmarks **Palpable Posterior Medial Anatomy** - Medial femoral epicondyle (proximal landmark) - Adductor tubercle (posterior superior medial femur) - Posteromedial tibial margin (palpable border) - Medial tibial plateau (target area) ### Neurovascular Anatomy - CRITICAL **Popliteal Artery and Vein** - **Location**: Anterior to posterior capsule and tibial plateau - **Distance from posterior plateau**: 5-10mm - **At risk**: Anterior cortex drilling, screw penetration, retractor placement - **Course**: Runs through popliteal fossa, branching at inferior border of popliteus - **Protection**: Avoid anterior dissection, never retract anteriorly, confirm screw length **Tibial Nerve** - Posterior and lateral to surgical field - Protected by medial head of gastrocnemius - Usually safe if interval between gastroc and semimembranosus maintained **Saphenous Nerve** - Superficial nerve running with great saphenous vein - Exits adductor canal posteromedial to knee - **At risk**: Proximal skin incision, subcutaneous dissection - **Injury**: Medial leg and foot numbness **Common Peroneal Nerve** - Wraps around fibular neck laterally - Not at risk with posteromedial approach (too lateral) ### Ligamentous and Capsular Anatomy **Posteromedial Corner Structures** - **Posterior oblique ligament (POL)**: Thickening of posteromedial capsule - **Semimembranosus tendon**: Inserts on posteromedial tibia - Five arms: direct, reflected, popliteal, capsular, oblique - **Posterior horn medial meniscus**: Attached to posterior capsule **Superficial Medial Collateral Ligament** - Anterior to surgical interval - Usually not encountered unless injury extends anteriorly ### Muscular Anatomy **Medial Head of Gastrocnemius** - **Lateral boundary** of approach - Origin: Posterior medial femoral condyle - Protects tibial nerve posteriorly **Semimembranosus** - **Medial boundary** of approach - Insertion: Posteromedial tibia (five-arm complex) - Posterior to pes anserinus **Popliteus** - Originates lateral femoral condyle - Inserts posterior proximal tibia - Forms floor of popliteal fossa - Overlies popliteal vessels ### Step 1: Skin Incision **Incision Planning** - Longitudinal incision over posteromedial tibia - **Proximal extent**: Medial femoral epicondyle - **Distal extent**: 6-8cm distal to joint line - **Length**: 8-12cm depending on exposure needs **Skin Incision** - Curvilinear, slightly posterior to medial midline - Sharp dissection through skin and subcutaneous tissue - Identify and protect saphenous vein and nerve if encountered **Hemostasis** - Electrocautery for subcutaneous vessels - Preserve saphenous vein if possible (collateral drainage) ### Step 2: Identify Anatomic Interval **Palpate Key Structures** - Medial head of gastrocnemius (lateral, feels like muscle belly) - Semimembranosus tendon (medial, feels cord-like) - Interval between them (natural plane) **Superficial Dissection** - Incise fascia overlying gastrocnemius and semimembranosus - Develop plane between muscles using blunt dissection - Separate muscles with retractors **Deep Dissection** - Continue dissection toward posterior capsule - Stay on bone (subperiosteal) to avoid vascular structures - Posterior capsule becomes visible ### Step 3: Capsular Exposure and Opening **Expose Posterior Capsule** - Retract gastroc laterally (tibial nerve protected behind it) - Retract semimembranosus medially - Posterior capsule exposed **Capsular Incision** - Incise posterior capsule longitudinally - Stay directly on bone (avoid anterior dissection) - Expose posterior aspect of medial tibial plateau **Joint Assessment** - Visualize posteromedial articular surface - Assess fracture pattern (coronal split, depression) - Palpate for posterior meniscus tear NEVER dissect anterior to posterior capsule without direct visualization - popliteal vessels are 5-10mm anterior to posterior tibial plateau. Any "blind" dissection anteriorly risks catastrophic vascular injury. ### Step 4: Fracture Reduction **Assess Fracture Pattern** - Coronal split (most common posteromedial pattern) - Posterior depression - Comminution **Reduction Techniques** *Option 1: Direct Manipulation* - Use reduction forceps to compress split fragments - Pry depressed fragments upward from posterior *Option 2: Anterior Approach First* - If combined with anterior approach, reduce from anterior first - Then secure posterior fragment from posteromedial *Option 3: Joystick Technique* - Place K-wire or small Schanz pin in posterior fragment - Use as joystick to manipulate fragment **Provisional Fixation** - K-wires to hold reduction - Verify on fluoroscopy (AP, lateral, oblique) **Critical Point: Screw Direction** - Screws from posteromedial should aim anterolateral - **AVOID**: Aiming anterior (popliteal vessel risk) - Measure screw length carefully (do NOT penetrate anterior cortex) **Critical principle**: Anterior cortex penetration = popliteal artery injury (catastrophic complication) **Screw length measurement protocol**: 1. **Use fluoroscopy** to confirm screw depth on BOTH AP and lateral views 2. **Measure multiple times** (at least 2-3 measurements per screw) 3. **Always err on the side of TOO SHORT** (better underpenetration than overpenetration) 4. Use **bicortical drill stops** if available (prevents inadvertent overdrill) 5. **Check screw length visually** before insertion (compare to measured depth) **Screw direction from posteromedial approach**: - Aim screws **anterolateral** (away from popliteal vessels) - **AVOID** aiming anterior (directs toward vessels) - Use fluoroscopy to confirm trajectory before drilling **Consequence of anterior cortex penetration**: - Popliteal artery laceration - Limb-threatening vascular injury - Immediate vascular surgery consultation required - Potential limb loss if delayed repair ### Step 5: Definitive Fixation **Posteromedial Buttress Plate** - Select appropriate posteromedial plate (anatomic pre-contour) - Position plate on posteromedial tibia - Proximal: Just distal to joint line - Aligned with posterior tibial border - Confirm position with fluoroscopy **Screw Insertion** - **Proximal screws** (subchondral support): - Aim anterolaterally (NOT anterior) - Locking screws preferred - Measure carefully (fluoroscopy confirmation) - Bicortical ONLY if absolutely safe trajectory - **Distal screws** (diaphyseal purchase): - Bicortical screws - 3-4 screws distal to fracture **Alternative: Lag Screws Only** - If simple coronal split fracture - Lag screws from posteromedial to anterolateral - Typically 6.5mm partially threaded cannulated screws - Compression across split **Ligamentous Repair (If Needed)** - Repair avulsed semimembranosus if present - Repair POL capsular tears - Suture meniscal root tears ### Step 6: Final Assessment **Fluoroscopic Verification** - AP, lateral, oblique views - Confirm reduction (less than 2mm step-off) - Confirm no anterior cortex penetration - Assess alignment **Stability Testing** - Gentle ROM through flexion/extension - Assess varus/valgus stability - Check for gapping ### Step 7: Closure **Capsular Repair** - Re-approximate posterior capsule with 0 or #1 Vicryl - Watertight closure (reduce hemarthrosis) **Muscular Layer** - Allow gastrocnemius and semimembranosus to fall back together - No need to suture muscles (interval approach) **Fascial Closure** - Close fascia with #1 Vicryl **Drain Placement** - Consider deep drain (10Fr Blake) - Remove when output less than 30mL/24hrs **Subcutaneous and Skin** - 2-0 Vicryl subcutaneous - 3-0 nylon or staples for skin Post-operative neurovascular checks are MANDATORY every 1-2 hours for first 24 hours - high risk of compartment syndrome and occult vascular injury. Have low threshold for CT angiography if any concern. ### Intraoperative Complications **Popliteal Vessel Injury (Most Feared - 2-5%)** - **Mechanism**: - Anterior cortex penetration by screw - Direct injury during anterior dissection - Retractor injury - **Recognition**: Sudden hemorrhage, expanding hematoma - **Management**: - Direct pressure - Call vascular surgery IMMEDIATELY - Proximal and distal control if possible - Repair vs bypass depending on injury **Tibial Nerve Injury (Less than 1%)** - Lateral retraction of gastrocnemius - **Prevention**: Gentle retraction, identify nerve course - **Management**: Release retraction, document **Saphenous Nerve Injury (5-10%)** - Subcutaneous dissection - **Result**: Medial leg/foot numbness - **Prevention**: Careful superficial dissection - **Often unavoidable** - counsel patient preoperatively ### Early Postoperative Complications **Compartment Syndrome (5-10% in high-energy injuries)** - High index of suspicion - Frequent neuro-vascular checks - **Management**: Immediate fasciotomy if suspected **Occult Vascular Injury** - May not be apparent intraoperatively if tourniquet used - Present postop with ischemia, delayed hematoma - **Prevention**: Deflate tourniquet before closure, check pulses - **Management**: CT angiography, vascular surgery consult **Wound Complications** - Hematoma: Common due to posterior approach - Infection: Less than 2% - **Prevention**: Drain placement, hemostasis ### Late Complications **Post-traumatic Arthritis (20-30%)** - Despite anatomic reduction - Risk factors: articular comminution, meniscectomy **Malunion** - From inadequate reduction - Causes varus instability, medial pain **Hardware Prominence** - Posteromedial plate palpable - May require removal (10-15% of cases) **Chronic Pain and Stiffness** - Extensive soft tissue dissection - Prolonged immobilization ### Immediate Care (0-48 hours) **Neurovascular Monitoring - CRITICAL** - Check pulses, capillary refill, sensation every 1-2 hours - Compartment checks (pain, tightness, passive stretch pain) - Have low threshold for CT angiography if any concern **Positioning** - Leg elevated - Knee immobilizer or hinged brace locked in extension **Pain Management** - Multimodal analgesia - Avoid femoral nerve block (masks compartment syndrome) - Regional anesthesia OK but monitor closely **Drain Management** - Remove when output less than 30mL/24hrs (typically 48hrs) ### Weight-Bearing Protocol **Simple Fractures (Isolated Posteromedial)** - Toe-touch weight-bearing (TTWB) 6-8 weeks - Progressive weight-bearing 8-10 weeks - Full weight-bearing 10-12 weeks **Complex/Bicondylar Fractures** - Non-weight-bearing (NWB) 8-12 weeks - Very gradual progression based on healing ### ROM Protocol **Week 0-2** - Knee immobilizer, gentle passive ROM to 60 degrees - Avoid varus stress (protects medial fixation) **Week 2-6** - Progress ROM to 90 degrees - Active-assisted ROM **Week 6+** - Unrestricted ROM exercises - Strengthening (quad, hamstrings) ### Radiographic Follow-up **2 Weeks**: AP, lateral, oblique - assess reduction, hardware **6 Weeks**: Repeat films before increasing weight-bearing **12 Weeks**: Assess union (3 of 4 cortices healed) **6 Months, 1 Year**: Long-term assessment for arthritis ### Physical Therapy **Phase 1 (0-6 weeks)**: Protection, gentle ROM **Phase 2 (6-12 weeks)**: Progressive strengthening, weight-bearing advancement **Phase 3 (12+ weeks)**: Functional restoration, sport-specific training ### Return to Activity **Sedentary Work**: 8-12 weeks **Light Labor**: 12-16 weeks **Heavy Labor**: 4-6 months **Contact Sports**: 6-9 months **Full Activities**: 6-12 months ## Exam Day Cheat Sheet ## Evidence-Based Practice ## Australian Context The posteromedial approach to the knee for tibial plateau fractures represents a specialized, high-risk technique employed primarily in major Australian trauma centers with expertise in complex periarticular fracture management. Given the proximity of popliteal vessels (5-10mm anterior to the posterior tibial plateau) and the technical demands of prone positioning or supine positioning with leg hanging, this approach is typically reserved for experienced trauma surgeons at Level 1 trauma facilities (Royal Melbourne Hospital, Royal Adelaide Hospital, Royal Brisbane Hospital, John Hunter Hospital). The Australian Orthopaedic Trauma Society (ANZOTS) guidelines emphasize CT-based fracture characterization for all displaced tibial plateau fractures, with posteromedial column involvement identified in approximately 40% of high-energy bicondylar patterns (Schatzker V-VI). Australian practice increasingly favors staged dual-plating strategies for bicondylar fractures with posteromedial involvement, with lateral column fixation performed first (day 0-1) followed by posteromedial fixation 7-14 days later once soft tissue swelling has improved. This staged approach minimizes compartment syndrome risk (5-10% with single-stage dual-plating vs less than 3% with staged procedures) and allows optimization of patient positioning for each approach. Vascular surgery availability is mandatory for posteromedial approaches across Australian trauma centers, with formal consultation and operating room standby arranged preoperatively for all cases given the 2-5% popliteal vessel injury rate reported in Australian trauma registries. Antibiotic prophylaxis follows Therapeutic Guidelines (eTG) with cefazolin 2g IV at induction, redosing every 4 hours for prolonged procedures. Tourniquet use in posteromedial approaches is controversial in Australian practice - some surgeons avoid tourniquets entirely (preserving ability to detect vascular injury intraoperatively), while others use intermittent inflation (deflate every 60 minutes to check for bleeding). Postoperative monitoring protocols mandate neurovascular checks every 1-2 hours for 24 hours with compartment syndrome surveillance, as high-energy medial plateau fractures carry elevated risk (5-10%) particularly in Australian mining and industrial accident cohorts presenting to regional trauma centers. Workers' compensation schemes (WorkCover, icare) cover extended rehabilitation periods typical for these complex injuries (4-6 months to return to manual labor), with vocational retraining supported for patients unable to return to pre-injury occupations given the 20-30% post-traumatic arthritis rate at long-term follow-up.

Posteromedial Approach to Knee

Posteromedial Approach to Knee