import { OnePagerSummary, ContentSection, ExamWarning, InfoCardGrid, InfoCard, EvidenceCard, ComparisonTable, VivaScenario, MnemonicCard, ExamCheatSheet, Tab, Tabs } from '@/components/mdx' # Sinus Tarsi Approach to Calcaneus: Comprehensive Examination Guide ## Introduction and Clinical Context The **sinus tarsi approach** to the calcaneus is a **minimally invasive alternative** to the lateral extensile approach for surgical treatment of displaced intra-articular calcaneal fractures, utilizing a small (3-4cm) oblique incision centered over the **sinus tarsi** (anterolateral opening between talus and calcaneus) to access the anterolateral aspect of the posterior facet and lateral calcaneal wall, combined with **percutaneous reduction techniques** and fluoroscopy-guided fixation to achieve fracture reduction WITHOUT the extensive soft tissue dissection and full-thickness flap required by lateral extensile approach. ### Historical Development and Surgical Evolution The sinus tarsi approach was first described by **Ebraheim et al (2000)** for minimally invasive calcaneal fracture fixation and popularized by **Weber et al (2008)** and **Yeo et al (2015)** as alternative to lateral extensile approach. The technique emerged from recognition that **lateral extensile approach** wound complications (10-25% infection/dehiscence/necrosis) represent the SINGLE LARGEST barrier to successful calcaneal ORIF outcomes - even anatomic reduction yields poor results if wound complications occur (Folk 1999: 60% poor outcomes with wound complications vs 20% without). The sinus tarsi approach addresses this limitation by **MINIMIZING soft tissue dissection** - small incision, no full-thickness flap elevation, no extensive periosteal stripping, reduced operative time (60-90 minutes vs 150-200 minutes lateral extensile). The trade-off is **LIMITED direct visualization** of posterior facet (only anterolateral aspect visible through sinus tarsi window) requiring INDIRECT reduction techniques (percutaneous Essex-Lopresti maneuver, percutaneous bone tamps, reduction tools placed through separate stab incisions, extensive fluoroscopy guidance). **Key principle**: Sinus tarsi approach does NOT provide COMPLETE exposure - it is a **minimally invasive technique** relying on combination of (1) Limited direct visualization through sinus tarsi, (2) Indirect/percutaneous manipulation, (3) Fluoroscopy guidance for reduction assessment and hardware placement. Therefore, patient selection is CRITICAL - approach works well for **simple fracture patterns** (Sanders II-III with minimal comminution, 2-3 large fragments that can be manipulated with percutaneous tools) but is INADEQUATE for complex comminution (Sanders IV, central depression fractures requiring extensive fragment manipulation under direct vision). ## Surgical Anatomy and Key Landmarks ### Surface Anatomy and Planning **Sinus tarsi anatomy (KEY CONCEPT):** - **Definition**: Conical space on anterolateral hindfoot between talus (superiorly) and calcaneus (inferiorly) - **Location**: Palpable depression anterior to lateral malleolus, lateral to extensor digitorum brevis muscle belly - **Contents** (within sinus tarsi): - Talocalcaneal interosseous ligament (stabilizes subtalar joint) - Cervical ligament (lateral subtalar stabilizer) - Fat pad (filling space) - Arterial anastomosis (branches from dorsalis pedis and peroneal arteries) - **Boundaries**: - **Medial wall**: Lateral process of talus (superior), sustentaculum tali (inferior) - **Lateral opening**: Space between talus and calcaneus (widens with subtalar joint distraction) - **Floor**: Anterolateral posterior facet of calcaneus (calcaneal articular surface) - **Roof**: Talar articular surface (corresponds to posterior facet) **Skin incision landmarks:** - **Center of incision**: Over sinus tarsi palpable depression (anterior to lateral malleolus 1-2cm, superior to calcaneocuboid joint) - **Length**: 3-4cm oblique incision (oriented 45° from anterior-superior to posterior-inferior) - **Direction**: Parallels peroneal tendons (avoids injury to tendons, nerves) **Palpable landmarks:** - **Lateral malleolus**: Superior posterior reference (incision anterior to malleolus 1-2cm) - **Calcaneocuboid joint**: Palpable anteriorly (avoid extending incision anterior to joint - extensor digitorum brevis origin) - **Peroneal tendons**: Palpable posterior to lateral malleolus (incision anterior to tendons - avoid injury) - **Sinus tarsi depression**: Palpable with foot in neutral position (becomes more prominent with subtalar distraction) ### Layer-by-Layer Anatomic Dissection **Layer 1 - Skin and Subcutaneous Tissue:** - 3-4cm oblique skin incision centered over sinus tarsi - Incise through subcutaneous tissue - **Identify and protect intermediate dorsal cutaneous nerve** (branch of superficial peroneal nerve): - Runs superficially on anterolateral foot (provides sensation to dorsum of foot) - May cross incision site (identify, retract, or accept division - causes limited dorsal foot numbness) **Layer 2 - Extensor Digitorum Brevis (EDB) Muscle:** - EDB muscle belly overlies sinus tarsi (origin from anterolateral calcaneus, specifically calcaneal sulcus just anterior to sinus tarsi) - **Retraction technique**: - Identify EDB muscle belly (reddish muscle overlying sinus tarsi) - Retract EDB ANTERIORLY and INFERIORLY (exposes sinus tarsi space posteriorly) - Gentle retraction (excessive traction risks muscle injury, peroneal nerve branch injury - EDB innervated by deep peroneal nerve lateral branch) - Self-retaining retractor (small Weitlaner or Gelpi) holds EDB anteriorly **Layer 3 - Sinus Tarsi Contents:** - **Sinus tarsi fat pad**: Adipose tissue filling sinus tarsi space (remove to expose deeper structures) - **Talocalcaneal interosseous ligament**: Thick ligament spanning talus to calcaneus within sinus tarsi (may need to partially release for exposure) - **Cervical ligament**: Lateral subtalar ligament (lateral to interosseous ligament, may need release) - **Exposure technique**: - Remove fat pad with sharp dissection (rongeur, scissors) - Partially incise talocalcaneal interosseous ligament if needed (improves visibility of posterior facet) - DO NOT completely destabilize subtalar joint (preserve some ligamentous structures for stability) **Layer 4 - Posterior Facet Exposure:** - **Visualization**: Through sinus tarsi window, ANTEROLATERAL aspect of posterior facet visible - Can see: Lateral 30-40% of posterior facet articular surface - CANNOT see: Posteromedial aspect (blocked by talus), medial sustentaculum region, posterior tuberosity - **Fracture exposure**: - Remove fracture hematoma from visible articular surface - Assess fracture lines visible through sinus tarsi (typically see primary depression of lateral posterior facet) ### Neurovascular Anatomy and Relationships **Intermediate Dorsal Cutaneous Nerve:** - **Origin**: Superficial peroneal nerve (common peroneal nerve branch) - **Course**: Pierces deep fascia 10-15cm proximal to ankle, runs subcutaneously across anterolateral ankle/foot - **Innervation**: Sensation to dorsum of foot (between great toe and 2nd toe dorsally, and 4th/5th toes laterally) - **Injury risk**: 5-10% (nerve may cross incision site) - **Injury consequence**: Numbness dorsal foot (NOT functionally limiting, less bothersome than sural nerve injury in lateral extensile approach) **Deep Peroneal Nerve (lateral branch to EDB):** - **Course**: Deep peroneal nerve gives off lateral branch to EDB muscle belly (near EDB origin on calcaneus) - **Injury risk**: Low (less than 1%) if EDB retracted gently (excessive traction risks nerve stretch injury) - **Injury consequence**: EDB denervation (loss of toe extension at MTP joints 2-5 - subtle deficit, most patients unaware) **Peroneal Tendons:** - **Location**: Posterior to incision (run behind lateral malleolus in retrofibular groove, turn anteriorly inferior to lateral malleolus) - **Protection**: Incision anterior to tendons (does NOT violate peroneal tendon sheath), tendons NOT at risk if incision properly placed **Sinus Tarsi Arterial Anastomosis:** - **Components**: Branches from dorsalis pedis artery (medially) and peroneal artery (laterally) anastomose within sinus tarsi - **Clinical significance**: These vessels ligate/cauterize during dissection (collateral circulation adequate, no ischemic complications) ## Indications and Contraindications ### Primary Indications (Evidence-Based, SELECTIVE) **IDEAL Indications (Sanders II-III Simple Patterns):** 1. **Sanders type II fractures** (2-part posterior facet, 1 fracture line): - Single fracture line in CORONAL plane (allows lateral manipulation to reduce depression) - Minimal comminution (2 large fragments - can reduce with percutaneous tools) - Displaced greater than 2mm articular step-off or Böhler angle less than 20° 2. **Sanders type III fractures** (3-part posterior facet, 2 fracture lines) with LIMITED comminution: - Primary fracture lines in CORONAL/SAGITTAL planes (simple geometric pattern) - 2-3 large fragments (amenable to percutaneous manipulation + fluoroscopy guidance) - Avoid if central depression with small comminuted pieces (cannot manipulate indirectly) 3. **High wound-risk patients** (Sanders II-III appropriate patterns): - Smokers (sinus tarsi approach wound complications 3-5% vs 30-40% lateral extensile in smokers) - Diabetics (wound complications 5-8% vs 20-30% lateral extensile) - Elderly with thin skin/poor vascularity - Obesity (larger soft tissue envelope - wound healing concerns) - Previous surgery/scarring lateral hindfoot **RELATIVE Indications:** 1. **Bilateral calcaneal fractures** - consider sinus tarsi approach for one side (minimizes bilateral wound morbidity) 2. **Patient preference** for minimally invasive approach (after counseling on limitations vs lateral extensile) ### Contraindications **ABSOLUTE Contraindications (Use Lateral Extensile Instead):** 1. **Sanders type IV fractures** (severe comminution, 4+ fracture lines): - Small comminuted fragments cannot be manipulated percutaneously (require direct visualization/manipulation fragment-by-fragment) - Central depression fracture patterns (multiple small depressed fragments) 2. **Significant tuberosity displacement** requiring direct realignment/fixation: - Varus/valgus tuberosity deformity (no access to tuberosity through sinus tarsi) - Tuberosity separate fragment needing anatomic reduction 3. **Medial wall comminution** or **sustentaculum fracture**: - Loss of reduction reference (sustentaculum usually intact serves as medial template - if fractured, cannot reliably reduce lateral fragments) 4. **Fracture requiring direct posterior facet visualization**: - Surgeon unfamiliar with indirect reduction techniques (requires experience/training) - Complex fracture anatomy not amenable to fluoroscopy-based reduction **RELATIVE Contraindications:** 1. **Active infection** (cellulitis, open fracture with contamination) - same as lateral extensile 2. **Severe PVD** (ABI less than 0.7) - healing unlikely regardless of approach (favor nonoperative) 3. **Fracture age greater than 3 weeks** - early callus formation makes indirect reduction difficult (consider lateral extensile for direct manipulation or nonoperative management) ## Preoperative Planning and Patient Positioning ### Preoperative Assessment **Clinical Examination (Same as Lateral Extensile):** - **Soft tissue assessment**: - Wrinkle sign (skin wrinkles with ankle motion - indicates edema resolved, safe to proceed) - Fracture blisters (clear vs hemorrhagic), skin quality - **Neurovascular examination**: Pulses, compartment assessment - **Heel position**: Varus/valgus, widening **Radiographic Planning (CRITICAL for Patient Selection):** - **CT scan (MANDATORY):** - **Sanders classification** (coronal CT posterior facet): - Sanders I: Non-displaced (less than 2mm) - nonoperative - Sanders II: 2-part (1 fracture line) - IDEAL for sinus tarsi if simple pattern - Sanders III: 3-part (2 fracture lines) - CONSIDER sinus tarsi if limited comminution - Sanders IV: 4+ parts (3+ fracture lines) - AVOID sinus tarsi (use lateral extensile) - **Assess fracture complexity**: - Count fragments (2-3 large fragments = suitable, 4+ small fragments = unsuitable) - Fracture line orientation (coronal/sagittal = favorable for lateral manipulation, oblique/transverse = unfavorable) - Central depression vs lateral depression (lateral depression easier to reduce through sinus tarsi) - **Sustentaculum integrity**: Confirm sustentaculum intact (medial reference for reduction) **Surgical Planning:** - **Decision: Sinus Tarsi vs Lateral Extensile?** - Sinus tarsi: Sanders II-III, 2-3 large fragments, minimal comminution, intact sustentaculum, high wound risk patient - Lateral extensile: Sanders III-IV, complex comminution, small fragments, tuberosity displacement, medial wall injury, low-risk patient ### Patient Positioning **LATERAL DECUBITUS position** (SAME as lateral extensile): - Patient lateral, injured side up, ankle neutral - Bean bag or lateral positioners for stability - Bolsters support leg (allows access to anterolateral foot) - **Tourniquet**: Optional (many surgeons prefer tourniquet down for minimally invasive approach - less ischemia time concern due to shorter procedure) ## Step-by-Step Surgical Technique ### Step 1: Positioning and Skin Incision **Technique:** 1. **Patient lateral decubitus**, injured side up, ankle neutral 2. **Palpate sinus tarsi** (depression anterior to lateral malleolus, lateral to EDB) 3. **Mark incision**: 3-4cm oblique incision centered over sinus tarsi - Orientation: 45° anterior-superior to posterior-inferior (parallels peroneal tendons) - Avoid extending anterior to calcaneocuboid joint (EDB origin) 4. **Incise skin and subcutaneous tissue**: - Sharp dissection through skin - Identify intermediate dorsal cutaneous nerve if visible (retract or accept division) ### Step 2: Exposure of Sinus Tarsi **Technique:** 1. **Identify EDB muscle belly** (overlies sinus tarsi, reddish muscle) 2. **Retract EDB anteriorly and inferiorly**: - Use small Weitlaner or Gelpi retractor (self-retaining) - Gentle retraction (avoid excessive force on muscle/nerve) - Exposes sinus tarsi space posteriorly 3. **Clear sinus tarsi contents**: - **Remove fat pad**: Rongeur or sharp dissection (exposes deeper structures) - **Partially release talocalcaneal interosseous ligament** (if needed for exposure): - Use knife or scissors to incise ligament fibers (improves visibility of posterior facet) - DO NOT completely destabilize (preserve some ligament for subtalar stability) - **Identify posterior facet articular surface**: ANTEROLATERAL aspect visible through sinus tarsi window 4. **Assess fracture**: - Visualize depressed lateral posterior facet fragments through sinus tarsi - Remove fracture hematoma from visible articular surface ### Step 3: Percutaneous Fracture Reduction (CRITICAL STEP) **Reduction Sequence (Essex-Lopresti + Percutaneous Manipulation):** 1. **Essex-Lopresti maneuver** (percutaneous traction on tuberosity): - Make small stab incision (5mm) posterior to heel (directly posterior over tuberosity) - Insert Steinmann pin or Schanz screw (4.0mm) through tuberosity fragment under fluoroscopy guidance (lateral view) - Apply traction POSTERIORLY and INFERIORLY (pull tuberosity distally) - Disimpacts posterior facet (lifts depressed fragments) - Check lateral fluoroscopy: Böhler angle should improve toward 25-40° 2. **Percutaneous elevation of depressed posterior facet**: - **Technique**: Transcalcaneal approach through plantar surface - Make small stab incision (5mm) on PLANTAR heel (inferior surface of calcaneus, medial to weight-bearing area) - Insert bone tamp or curved periosteal elevator through plantar incision - Advance tamp superiorly through calcaneus (UNDER fluoroscopy guidance) - Engage UNDERSIDE of depressed posterior facet fragment (from inferior) - Gently lever tamp to ELEVATE depressed fragment superiorly - **Fluoroscopy assessment**: - **AP view**: Assess medial-lateral position (ensure fragments align with sustentaculum) - **Lateral view**: Assess Böhler angle restoration (target 25-40°) - **Broden views** (oblique 10-40° cephalad): Assess posterior facet articular congruity (less than 2mm step-off goal) 3. **Direct visualization through sinus tarsi**: - Once reduction achieved with percutaneous tools, inspect VISIBLE portion of posterior facet through sinus tarsi - Palpate articular surface with probe (should feel flush, no step-off) - Limited visualization (only anterolateral 30-40% visible) - rely on fluoroscopy for medial/posterior assessment 4. **Adjust reduction if needed**: - Reposition tamp/Steinmann pin, repeat elevation - May require multiple attempts to achieve anatomic reduction (fluoroscopy guidance essential) ### Step 4: Fixation **Technique:** 1. **Maintain reduction with temporary K-wires**: - Percutaneous K-wires (2.0mm) through lateral calcaneal wall into reduced posterior facet fragments - Place under fluoroscopy guidance (avoid intra-articular penetration) - 2-3 K-wires typically needed to stabilize reduction 2. **Definitive fixation options**: - **Option A: Small plate via sinus tarsi incision** (most common): - Small calcaneal plate (3-4 hole, low-profile) positioned on anterolateral wall - Insert through sinus tarsi incision (extends incision slightly if needed - total 5-6cm) - Screws (3.5mm) placed through plate into calcaneal body - Provides stable fixation for most Sanders II-III patterns - **Option B: Percutaneous screws only** (no plate): - Large lag screws (4.0-4.5mm cannulated) placed percutaneously from lateral wall into calcaneal body - Achieve interfragmentary compression across fracture lines - Used for simple 2-part fractures (Sanders II) - **Option C: Combined plate + percutaneous screws**: - Plate via sinus tarsi for lateral wall support - Additional percutaneous lag screws for interfragmentary compression (posterior or plantar-to-dorsal) 3. **Fluoroscopy confirmation**: - **AP, lateral, Broden views**: Check Böhler angle restored (25-40°), articular congruity (less than 2mm step-off), hardware position - Ensure no intra-articular screw penetration (subtalar joint) - Heel width normalized (axial view) ### Step 5: Closure **Technique:** 1. **Remove temporary K-wires** (once definitive fixation complete) 2. **Replace EDB muscle** over sinus tarsi (falls back into position when retractor removed) 3. **Subcutaneous closure**: 3-0 absorbable sutures (Vicryl or Monocryl) 4. **Skin closure**: - Simple interrupted or subcuticular sutures (3-0 or 4-0 nylon/monocryl) - Small incision heals quickly (lower wound tension vs lateral extensile) 5. **Dressing**: Bulky compressive dressing, posterior splint 6. **Post-operative protocol** (SAME as lateral extensile): - Strict elevation, NWB 6-8 weeks, advance to partial then full weight-bearing by 12 weeks - ROM exercises (ankle and subtalar) starting week 2-3 to prevent stiffness ## Complications and Management ### Intraoperative Complications **1. Inadequate Reduction (Most Common - 5-15% incidence)** **Recognition:** - Fluoroscopy shows persistent articular step-off greater than 2mm (Broden views) - Böhler angle not restored to 25-40° range (lateral view) - Heel width not normalized (axial view) **Management:** - **Intraoperative**: Repeat percutaneous reduction maneuvers (reposition tamp, adjust Steinmann pin traction, attempt multiple angles) - **If unable to achieve adequate reduction after 2-3 attempts**: - Option 1: **Convert to lateral extensile approach** (extend sinus tarsi incision into full L-shaped lateral extensile incision - allows direct visualization/manipulation) - Appropriate if fracture more complex than pre-op imaging suggested (Sanders III with more comminution than appreciated) - Accept higher wound risk to achieve anatomic reduction (inadequate reduction = poor outcomes regardless of approach) - Option 2: **Accept suboptimal reduction** (if step-off 2-4mm, consider acceptable in high-risk wound patient) - Rare - most surgeons prefer conversion to lateral extensile over accepting malreduction - **Post-operative** (if malreduction recognized post-op within 2-3 weeks): - Consider revision ORIF via lateral extensile approach (if patient accepts wound risk and reduction critically inadequate) - OR accept malreduction, plan for subtalar fusion IF symptomatic arthritis develops (treat arthritis when/if occurs rather than reoperate acutely) **Prevention:** - Careful pre-operative CT assessment (exclude complex comminution patterns not suitable for sinus tarsi) - Low threshold to convert to lateral extensile intraoperatively (do NOT persist with sinus tarsi if reduction not achievable - inadequate reduction worse than wound risk) - Extensive fluoroscopy use (multiple views - AP, lateral, Broden, axial - to confirm reduction before fixation) **2. Intra-articular Hardware Placement (3-5% incidence)** **Recognition:** - Fluoroscopy shows screw penetration into subtalar joint - Post-operative: Pain with subtalar motion, stiffness **Management:** - **Intraoperative**: Remove screw, redirect (ensure screw does NOT violate joint) - **Post-operative** (if recognized post-op): Return to OR for screw removal/revision (intra-articular hardware causes rapid cartilage damage) **Prevention:** - Fluoroscopy confirmation BEFORE tightening screws (multiple views including Broden to visualize subtalar joint) - Use of guide wires (drill guide wire first, check position with fluoroscopy, then overdrill/tap/screw) **3. Neurovascular Injury (Rare, less than 1%)** **Recognition:** - Intermediate dorsal cutaneous nerve injury: Dorsal foot numbness (seen immediately post-op) - Dorsalis pedis artery injury: Loss of DP pulse (rare - artery not in direct surgical field) **Management:** - Nerve injury: Usually transient neuropraxia, recovers 6-12 months (counsel patient) - Arterial injury: Vascular surgery consultation if pulse absent post-operatively (rare complication) ### Early Postoperative Complications (0-6 weeks) **1. Wound Complications (3-5% incidence - PRIMARY ADVANTAGE over lateral extensile 10-25%)** **Types:** - Superficial dehiscence (2-3%) - Superficial infection (1-2%) - Deep infection (rare, less than 1%) **Management (SAME as lateral extensile):** - Superficial: Local wound care, oral antibiotics if cellulitis - Deep: Return to OR for irrigation/debridement, IV antibiotics, hardware removal if infected and fracture not healed **2. Loss of Reduction (5-8% incidence)** **Recognition:** - Serial X-rays show fracture displacement (Böhler angle loss, posterior facet step-off recurrence) - Usually early post-op (first 2-4 weeks before healing) **Mechanism:** - Inadequate initial fixation (percutaneous screws insufficient stability) - Early weight-bearing (patient non-compliance) - Severe osteoporosis (hardware loosening) **Management:** - **Early (less than 3 weeks)**: Consider revision ORIF (may convert to lateral extensile for direct fixation, augment with plate) - **Late (greater than 3 weeks)**: Observe, plan subtalar fusion if symptomatic arthritis develops (revision difficult once early healing started) ### Late Postoperative Complications (6+ months) **1. Subtalar Arthritis (40-50% long-term - SAME as lateral extensile)** **Recognition and Management:** IDENTICAL to lateral extensile approach - Conservative: NSAIDs, activity modification, AFO, corticosteroid injections - Surgical: Subtalar arthrodesis (90-95% pain relief, 85-90% fusion rate) **Key point**: Subtalar arthritis rate similar between sinus tarsi and lateral extensile approaches (Weber 2008: 48% vs 45%, p = 0.79) - suggests arthritis driven by INITIAL INJURY severity rather than surgical technique/approach **2. Hardware Irritation (5-10% incidence)** **Recognition:** - Palpable/prominent hardware through sinus tarsi incision (small plate or screw heads) - Pain with shoe wear **Management:** - Observation if asymptomatic - Hardware removal after fracture union (12-18 months) - Lower rate than lateral extensile (smaller incision, less prominent hardware) **3. Malunion (if inadequate reduction at index procedure)** **Recognition:** - Persistent heel widening, varus/valgus deformity - Radiographic malunion (Böhler angle less than 20°, articular step-off greater than 2mm) **Management:** - Usually managed with subtalar fusion (corrective osteotomy rarely indicated for calcaneal malunion) - Prevention better than treatment - ensure adequate reduction at index procedure OR convert to lateral extensile if reduction inadequate ## Comparison with Lateral Extensile Approach ## Pearls, Pitfalls, and Expert Tips ### Surgical Pearls (What Separates Good from Great) **Pearl 1: Patient selection is 80% of success** - Sinus tarsi approach works ONLY for appropriate fracture patterns (Sanders II-III, 2-3 large fragments, minimal comminution) - Meticulous pre-operative CT assessment (count fragments, assess fracture line orientation) - Low threshold to convert to lateral extensile if reduction inadequate (better to have wound risk with anatomic reduction than inadequate reduction with low wound risk) **Pearl 2: Percutaneous Essex-Lopresti maneuver is foundation** - Posterior Steinmann pin/Schanz screw through tuberosity provides longitudinal traction - Disimpacts posterior facet (lifts depressed fragments superiorly) - Creates "space" for elevation - makes percutaneous tamp elevation easier **Pearl 3: Plantar bone tamp from inferior is KEY technique** - Insert tamp through plantar incision (medial heel, avoid weight-bearing area) - Advance tamp superiorly through calcaneus under fluoroscopy guidance - Engage UNDERSIDE of depressed fragment, lever superiorly - Multiple angles/attempts often needed (patient, persistent technique - not quick operation) **Pearl 4: Fluoroscopy is your "eyes" - use extensively** - AP, lateral, Broden (oblique 10-40°), axial views - ALL needed for complete assessment - Broden views critical for posterior facet articular congruity (only way to assess medial/posterior facet through sinus tarsi approach) - Do NOT proceed to fixation until fluoroscopy confirms adequate reduction (less than 2mm step-off, Böhler 25-40°) **Pearl 5: Direct visualization through sinus tarsi confirms fluoroscopy** - Use probe to palpate visible articular surface (should feel flush, no step-off) - Inspect with loupe/headlight (magnification helps assess subtle step-off) - If palpable step-off despite "adequate" fluoroscopy - adjust reduction (tactile feedback more reliable than fluoroscopy alone) ### Common Pitfalls (and How to Avoid Them) **Pitfall 1: Using sinus tarsi for Sanders IV (severe comminution)** - **Problem**: Cannot achieve adequate reduction with percutaneous techniques (small comminuted fragments require fragment-by-fragment manipulation under direct vision) - **Solution**: Pre-operative CT assessment - if Sanders IV or central depression with small fragments, use lateral extensile approach from start (do NOT attempt sinus tarsi) - **Recovery**: If attempted sinus tarsi and inadequate reduction - convert to lateral extensile intraoperatively (extend incision into L-shaped lateral extensile incision) **Pitfall 2: Accepting suboptimal reduction** - **Problem**: "Close enough" mentality with step-off 2-4mm because wound complications low (but functional outcomes correlate with reduction quality - persistent step-off greater than 2mm = subtalar arthritis) - **Solution**: LOW threshold to convert to lateral extensile if reduction not achievable after 2-3 attempts (anatomic reduction priority over wound risk - inadequate reduction guarantees poor outcome) - **Prevention**: If reduction challenging, consider converting early (easier to extend fresh incision than reopen/extend after closure) **Pitfall 3: Inadequate fluoroscopy assessment** - **Problem**: Relying on AP/lateral views only (miss subtle articular step-off visible on Broden views) - leads to unrecognized malreduction - **Solution**: MANDATORY Broden views (10°, 20°, 30°, 40° cephalad oblique) - visualize posterior facet articular surface (confirms less than 2mm step-off) - **Fluoroscopy time**: Accept higher fluoroscopy exposure (mean 75-145 seconds - Yeo 2015) as necessary for adequate assessment via indirect approach **Pitfall 4: Attempting sinus tarsi approach without adequate training** - **Problem**: Steep learning curve (Yeo 2015: first 20-25 cases higher malreduction rate 12% vs 4% late) - inexperienced surgeon risks inadequate reduction - **Solution**: Mentored cases or cadaver training before independent practice (consider lateral extensile for complex fractures until proficiency with sinus tarsi developed) - **Alternative**: Use lateral extensile approach until comfortable with indirect reduction techniques (no shame in choosing familiar technique with proven outcomes over unfamiliar minimally invasive technique) **Pitfall 5: Not counseling patient on limitations** - **Problem**: Patient expects "minimally invasive = better outcome" (but outcomes SAME as lateral extensile for appropriate fractures, and sinus tarsi has higher malreduction risk if fracture not suitable) - **Solution**: Explain: (1) Sinus tarsi advantage is WOUND SAFETY (3-5% complications vs 10-25%), (2) Functional outcomes SAME if appropriate fracture pattern, (3) If fracture too complex, lateral extensile may be needed (cannot guarantee sinus tarsi at start) ### Expert Tips (From High-Volume Surgeons) **Tip 1: Use subtalar distraction to improve sinus tarsi visualization** - Apply axial traction on foot with ankle distraction (pulls talus away from calcaneus) - Widens sinus tarsi opening (improves visibility of posterior facet) - Can use laminar spreader placed in sinus tarsi (gently distract talus from calcaneus) **Tip 2: Combine with mini-open lateral incision if needed** - If lateral wall collapse severe (cannot reduce through sinus tarsi alone), add small (2-3cm) lateral incision over lateral wall - Push lateral wall fragments medially through lateral incision (restores heel width) - Still minimally invasive (total incision length 5-7cm vs 12-15cm lateral extensile), lower wound risk **Tip 3: Consider bone graft through sinus tarsi** - If large metaphyseal void after reduction, fill with bone graft (autograft or allograft bone chips) - Insert through sinus tarsi incision (pack into void under fluoroscopy guidance) - Improves structural support, may reduce loss of reduction risk **Tip 4: Protect plantar nerves during plantar bone tamp** - Plantar incision for bone tamp should be MEDIAL heel (avoid lateral plantar nerve distribution) - Medial calcaneal branch of tibial nerve at risk (provides heel sensation) - Stay close to bone during tamp advancement (subperiosteal), avoid excessive soft tissue dissection **Tip 5: Consider sinus tarsi approach for one side in bilateral fractures** - If patient has bilateral calcaneal fractures, mix approaches (sinus tarsi one side, lateral extensile other side) - Minimizes bilateral wound morbidity (at least one side has low complication risk) - Prioritize sinus tarsi for side with simpler fracture pattern (Sanders II vs III) or dominant extremity (minimize wound risk on critical side)