import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' ## Indications and Contraindications **Unstable Hip Joint** - Posterior wall involvement >40% (dynamic or static instability) - Positive dynamic stress test under fluoroscopy - Subluxation on static imaging - Failed closed reduction of hip dislocation **Articular Incongruity** - Intra-articular fragments preventing concentric reduction - Marginal impaction requiring elevation - Step >2mm on CT - Gap >2mm between fragments **Mechanical Block** - Incarcerated labral tissue - Osteochondral fragments blocking reduction - Associated femoral head fracture (Pipkin) **Borderline Cases** - Posterior wall involvement 20-40% with positive stress test - Roof arc angle 45-55° (borderline stability) - Young, active patient with low-demand elderly might accept non-op - High-energy mechanism suggesting worse cartilage injury **Associated Injuries** - Femoral head impaction from posterior wall fragment - Associated posterior column injury - Sciatic nerve palsy (may decompress during ORIF) **Absolute** - Active infection - Medically unfit for surgery - Severe dementia with baseline non-ambulatory status - Skin compromise precluding surgical approach **Relative** - Delay >3 weeks with established callus - Severe osteoporosis (may not hold fixation) - Stable fracture with <20% wall involvement - Elderly low-demand patient with concentrically reduced hip **Non-operative Criteria** - Concentric hip reduction maintained - <20% posterior wall involvement - Negative dynamic stress test - Roof arc angles >55° on all views **Injury rate 5-15% (mostly neuropraxia)**. Exits greater sciatic notch, runs 2-3cm medial to acetabular rim, deep to piriformis. **Protection**: Identify early, vessel loop, flex hip/knee, limit retraction to 60 minutes continuously. **Life-threatening haemorrhage if injured**. Exits greater sciatic notch ABOVE piriformis. Supplies gluteus medius/minimus and TFL. **Protection**: No retraction above piriformis, stay inferior to notch. **Major bleeding risk**. Exits greater sciatic notch BELOW piriformis with sciatic nerve. **Protection**: Careful dissection at notch, identify before retracting, have vascular clamps ready. **Primary blood supply to femoral head**. Runs along inferior hip capsule. **Protection**: Limit anterior capsular dissection, preserve retinacular vessels, gentle femoral head manipulation. ## Pre-operative Planning **History** - Mechanism: Dashboard injury, fall from height, pedestrian vs vehicle - Time since injury (AVN risk increases after 6-12 hours dislocation) - Pre-injury mobility and functional status - Comorbidities affecting anaesthesia and healing **Examination** - Hip position: Shortened, flexed, internally rotated = posterior dislocation - Neurovascular status: **SCIATIC NERVE** - document peroneal and tibial components - Associated injuries: Knee (PCL), femoral shaft, spine - Skin integrity over posterior approach **Timing Considerations** - Hip dislocation: **EMERGENCY REDUCTION < 6 HOURS** (AVN risk) - Definitive ORIF: 3-10 days (allows swelling resolution, prevents callus) - >3 weeks: Significantly increased difficulty **Plain Radiographs** - AP pelvis: Assess congruency, dome involvement - **Judet oblique views** (45° rotation): - Obturator oblique: Shows POSTERIOR WALL and anterior column - Iliac oblique: Shows anterior wall and posterior column **CT with 3D Reconstruction (MANDATORY)** - Axial cuts: Marginal impaction, wall percentage, intra-articular fragments - Coronal/sagittal: Roof arc angles - 3D: Fracture configuration, fragment size, surgical planning **Key Measurements** - Posterior wall percentage (>40% = unstable) - Roof arc angles (<45° = unstable) - Marginal impaction depth and location - Femoral head injury (Pipkin classification) **Dynamic Stress Test (Borderline Cases)** - Under anaesthesia with fluoroscopy - Internally rotate hip while applying posterior force - Subluxation = unstable = needs ORIF **Expected Outcomes** - Good/excellent result in 80-90% with anatomic reduction - Return to pre-injury function 6-12 months - May require THA in 10-20% long-term **General Surgical Risks** - Infection: 2-5% (superficial), 1-3% (deep) - Thromboembolic disease: 5-10% DVT, 1-2% PE - Transfusion requirement: 30-50% **Specific Risks** - Sciatic nerve injury: 5-15% (1-3% permanent) - Heterotopic ossification: 20-30% without prophylaxis, 5-10% with - Post-traumatic arthritis: 20-40% long-term - AVN: 5-10% (higher with delayed reduction) - Loss of reduction: 5-10% - Intra-articular screw penetration: 5% (requiring removal) ## Equipment - 3.5mm pelvic reconstruction plates - 3.5mm cortical screws (various lengths) - 4.5mm screws for larger fragments - Spring plates for comminution - Absorbable screws (alternative for small fragments) - Pelvic reduction set - Ball spike pushers - Pointed reduction clamps - Schanz pins (5mm) - Plate bending irons - Bone graft instruments (if impaction) - C-arm fluoroscopy (essential) - Cell saver - Surgical headlight - Radiolucent table - Vessel loops for nerve protection - Bone graft (autograft or allograft) ## Anaesthesia and Positioning **Preferred**: General anaesthesia with muscle relaxation **Key Points**: - Cell saver recommended (blood loss 500-1500mL typical) - Induced hypotension may be used (MAP 60-70mmHg) - Adequate IV access for potential massive transfusion - Arterial line for monitoring **Antibiotic Prophylaxis**: - Cefazolin 2g IV within 60 minutes of incision - Redose at 4 hours or 1500mL blood loss - Clindamycin 900mg IV if penicillin allergy **Lateral Decubitus Position** 1. Affected side UP 2. Beanbag or pegboard for stability 3. Axillary roll to protect brachial plexus 4. All bony prominences padded: - Fibular head (peroneal nerve) - Lateral malleolus - Greater trochanter (contralateral) **Position Checklist**: - Pelvis perpendicular to floor - Hip and knee can flex/extend freely (to relax sciatic) - C-arm access confirmed (AP and lateral) - Table radiolucent **Exam Tip**: Flexing the hip and knee relaxes the sciatic nerve and improves visualization. The ability to manipulate the leg during surgery is a key advantage of lateral positioning for this approach. ## Surface Anatomy and Landmarks **Incision**: Curved incision from PSIS toward greater trochanter, then distally along posterior femoral shaft. Total length 15-20cm. ## Surgical Approach - Kocher-Langenbeck **Incision** - Start at PSIS - Curve toward greater trochanter (apex at trochanter) - Continue distally along posterior femur - Total length: 15-20cm **Superficial Dissection** 1. Incise skin and subcutaneous tissue 2. Identify fascia lata and gluteus maximus fibres 3. Split gluteus maximus BLUNTLY in line with fibres - Fibres run superolateral to inferomedial - Proximal: between upper 1/3 and lower 2/3 - Distal: posterior to IT band The superior gluteal nerve enters gluteus maximus 4-5cm above greater trochanter. Stay inferior to this level when splitting the muscle to avoid denervation of the superior portion. **Sciatic Nerve Identification** (CRITICAL STEP) 1. Palpate greater sciatic notch 2. Identify piriformis tendon (most superior rotator) 3. Sciatic nerve exits BELOW piriformis 4. Lies 2-3cm medial to acetabular rim 5. **Protect with vessel loop throughout case** **Short External Rotator Exposure** - Identify from superior to inferior: 1. **Piriformis** - most superior 2. **Superior gemellus** 3. **Obturator internus** 4. **Inferior gemellus** 5. **Quadratus femoris** - most inferior **Rotator Management** - Tag each tendon with heavy suture (for later repair) - Divide tendons 1cm from trochanteric insertion - Preserve muscle belly for vascularity - Flex and internally rotate hip to relax structures **Exam Tip**: The sciatic nerve is intimately related to the obturator internus - it lies just inferior and medial. When dividing the obturator, always visualise the nerve to avoid iatrogenic injury. **Posterior Capsulotomy** 1. Palpate femoral head through intact capsule 2. Perform T-shaped or inverted-L capsulotomy 3. Extend along acetabular rim and down femoral neck 4. **Limit ANTERIOR capsular dissection** (preserves MFCA) **Fracture Visualization** - Identify posterior wall fragment(s) - Assess comminution pattern - Extract intra-articular fragments and debris - Assess for marginal impaction (present in 50%) **Retractor Placement** - Cobra retractor on ischium (inferior) - Hohmann on ilium (superior) - Avoid excessive traction on sciatic nerve Marginal impaction is cartilage-covered bone depressed at the fracture edge. Present in **50% of posterior wall fractures**. If missed and not elevated, leads to rapid post-traumatic arthritis. Look for a subtle step at the articular margin. ## Operative Technique **Reduction Principles** - Goal: Anatomic reduction <2mm step or gap - <1mm = 88% good outcome - >2mm = 45% good outcome **Technique** 1. Clear fracture surfaces of soft tissue and clot 2. Identify marginal impaction if present 3. Use Schanz pins in ilium/ischium as joysticks 4. Ball spike pushers for fine manipulation 5. Pointed reduction clamps for provisional fixation **Marginal Impaction Management** 1. Make window in wall fragment if needed 2. Use curved osteotome to elevate depressed cartilage 3. Bone graft the defect (autograft or allograft) 4. Support with subchondral screws if needed **Exam Tip**: The classic sign of marginal impaction on CT is a double-density sign at the posterior wall margin - the depressed fragment appears as a separate line parallel to the acetabular surface. **Provisional Fixation** - Apply pointed reduction clamps across fracture - Multiple clamps may be needed for comminuted fractures - Confirm reduction with direct vision AND fluoroscopy **Lag Screw Technique** 1. Drill perpendicular to fracture plane 2. Overdrill near cortex (glide hole) 3. Measure depth, tap far cortex only 4. Insert 3.5mm cortical screw achieving compression 5. Typical: 2-4 lag screws for posterior wall **Safe Zone for Screws** - Aim from posterior toward anterosuperior - 45° cranial trajectory - Avoid intra-articular penetration (palpate joint surface) Risk 5-15% if not carefully assessed. Prevention: Check with fluoroscopy in MULTIPLE views (AP, obturator oblique, iliac oblique) AND directly palpate the articular surface through the capsulotomy before final tightening. **Plate Selection** - 3.5mm pelvic reconstruction plate (standard) - Pre-contoured posterior wall plates available - Spring plates for small or comminuted fragments **Plate Positioning** - Functions as BUTTRESS (prevents posterior displacement) - Lag screws provide compression; plate prevents migration **Fixation Points** - Proximal: 3-4 bicortical screws in ilium above fracture - Distal: 3-4 screws in ischium below fracture - Additional screws through plate holes into wall fragment **Contouring** - Plate must match posterior column anatomy - Use bending irons to achieve precise contour - Poor contour = loss of reduction when tightening screws **Exam Tip**: The plate functions as a BUTTRESS, not a compression device. The lag screws provide interfragmentary compression across the fracture. The plate prevents secondary displacement. This is a key concept for viva discussions. **Reduction Assessment** 1. Remove provisional clamps 2. Palpate articular surface through capsulotomy 3. Stress test hip - should be stable through ROM **Fluoroscopic Views (All MANDATORY)** - **AP pelvis**: Concentric reduction, no roof step - **Obturator oblique**: Posterior wall reduction (best view) - **Iliac oblique**: Column integrity - **Lateral**: Femoral head concentricity **Stability Testing** - Flex hip to 90° - Apply posterior force with internal rotation - Hip should not subluxate - If unstable - reassess reduction, consider larger plate **Capsular Repair** - Repair posterior capsule with interrupted #1 absorbable sutures - Capsular closure adds stability to construct **Short External Rotator Repair** - Use tagged sutures placed during exposure - Repair to greater trochanter with heavy non-absorbable (#2 Ethibond) - Anatomic repair sequence: piriformis → obturator/gemelli → quadratus - This reconstructs posterior hip stability **Layer Closure** 1. Deep drain in posterior hip region (19Fr) 2. Gluteus maximus fascia - interrupted absorbable 3. Fascia lata - interrupted absorbable 4. Subcutaneous - running absorbable 5. Skin - staples or subcuticular **Exam Tip**: Meticulous short external rotator repair is essential - these muscles are dynamic stabilisers of the hip. Failure to repair increases posterior instability risk and may worsen heterotopic ossification. ## Complications **Incidence**: 5-15% (mostly neuropraxia; 1-3% permanent) **Recognition** - Foot drop (peroneal more common than tibial) - Sensory loss: Peroneal = dorsum of foot; Tibial = sole - Document motor/sensory function preoperatively **Prevention** - Identify nerve early and protect with vessel loop - Flex hip and knee to relax nerve tension - Limit continuous retraction to <60 minutes - Use padded retractors only - Avoid posterior screw penetration toward notch **Management** - Document new deficit immediately postoperatively - Consider re-exploration if: - Complete deficit (not present preop) - Expanding haematoma - Suspected screw impingement - Most neuropraxia recovers 6-18 months - AFO for foot drop during recovery - EMG/NCS at 6 weeks to assess severity - Tendon transfer if no recovery by 12-18 months **Incidence**: 20-30% without prophylaxis; Brooker 3-4 in 10-15% **Recognition** - Decreasing ROM 4-8 weeks postop - Pain with motion - XR: Periarticular calcification (visible 3-6 weeks) **Prevention (MANDATORY)** - **Indomethacin 75mg daily × 6 weeks** (start within 24hr) - OR **Radiation 7-8 Gy single dose** within 72 hours - Minimise soft tissue trauma - Thorough irrigation - Early drain removal (24-48 hours) **Management** - Brooker 1-2: Observation (usually asymptomatic) - Brooker 3-4: Excision after maturation (12-18 months) - Continue physiotherapy to maintain motion - Restart prophylaxis at time of excision - 70-80% improved ROM after excision **Incidence**: 20-40% long-term (depends on reduction quality) **Recognition** - Progressive pain over months to years - Decreasing ROM - XR: Joint space narrowing, osteophytes, subchondral sclerosis **Prevention** - Anatomic reduction (<1mm ideal, <2mm acceptable) - Remove all intra-articular fragments - Elevate marginal impaction - Early ROM to maintain cartilage health - Treat associated femoral head injuries **Management** - Conservative: Activity modification, weight loss, NSAIDs, physiotherapy - Injections: Corticosteroid, hyaluronic acid - Definitive: Total hip arthroplasty - THA outcomes after acetabular fracture generally good **Incidence**: 5-10% isolated posterior wall; up to 25% if dislocation >12 hours **Recognition** - May not appear for 6-24 months - Groin pain, progressive - XR: Sclerosis, subchondral lucency, collapse - MRI: Most sensitive for early detection **Prevention** - **Emergency reduction of hip dislocation (<6 hours)** - Preserve medial femoral circumflex artery - Limit anterior capsular dissection - Gentle reduction technique **Management** - Pre-collapse (Ficat I-II): Core decompression ± biologics - Post-collapse (Ficat III-IV): Total hip arthroplasty - Protected weight bearing may slow progression **Incidence**: 5-10% **Recognition** - Increasing pain - Loss of reduction on follow-up XR - Hardware prominence or migration **Prevention** - Anatomic reduction before plate application - Adequate lag screw compression - Buttress plate with sufficient fixation proximal and distal - Address comminution (spring plates, bone graft) - Appropriate weight-bearing restrictions **Management** - Early (<6 weeks): Revision ORIF with larger construct - Late with acceptable alignment: Accept, progress WB if healing - Malunion/nonunion: Consider THA in elderly, revision ORIF in young **Incidence**: 2-5% superficial; 1-3% deep **Recognition** - Wound erythema, drainage, dehiscence - Fever, elevated WBC, CRP, ESR - Deep infection may present late (weeks to months) **Prevention** - Preoperative antibiotics within 60 minutes - Meticulous technique, minimise operative time - Copious irrigation (>6L) - Drain placement - Appropriate closure, avoid haematoma **Management** - Superficial: Oral antibiotics, wound care - Deep early (<3 weeks): I&D, retain hardware, IV antibiotics 6 weeks - Deep late: Hardware removal, debridement, antibiotic spacer, delayed reconstruction ## Post-operative Care **Recovery Room** - Neurovascular check documented (sciatic nerve function) - AP pelvis X-ray to confirm reduction and hardware position - Pain control: PCA or regional anaesthesia **Day 0-1** - Mobilise with physiotherapy when stable - Toe-touch weight bearing (TDWB) with frame/crutches - DVT prophylaxis: LMWH or DOAC per protocol - Drain removal when output <30mL per 8 hours (usually 24-48hr) **MANDATORY in all patients** **Option 1: Indomethacin** - 75mg daily (or 25mg TDS) for 6 weeks - Start within 24 hours postoperatively - Monitor for GI side effects **Option 2: Radiation** - 7-8 Gy single dose - Within 72 hours of surgery - Reserved for NSAID contraindications **Exam Tip**: HO prophylaxis reduces Brooker 3-4 HO from 25% to 5-10%. In exam discussions, always mention prophylaxis when discussing posterior approach to acetabulum - it's a key examiner expectation. **Weight Bearing** - Weeks 0-6: Toe-touch weight bearing (TDWB) - Weeks 6-8: Partial weight bearing (PWB) if healing on XR - Weeks 8-12: Progress to full weight bearing (FWB) **Range of Motion** - Week 1-2: Gentle passive ROM - Week 3+: Active-assisted ROM - No active hip flexion >90° for 6 weeks (protects rotator repair) - No resisted external rotation for 6 weeks **Hip Precautions** - Avoid combined flexion + adduction + internal rotation - Use abduction pillow for 6 weeks - Avoid low chairs, crossing legs **Follow-up Schedule** - 2 weeks: Wound check, staple removal - 6 weeks: XR (AP pelvis + Judet views), assess union - 12 weeks: XR, assess for FWB - 6 months: Clinical and radiological review - 1 year: Assess for arthritis, AVN - Annual: Long-term surveillance for arthritis ## Viva Scenarios ## Key Exam Points ## References 1. **Matta JM** (1996). Fractures of the acetabulum: accuracy of reduction and clinical results in patients managed operatively within three weeks after the injury. *J Bone Joint Surg Am* 78(11):1632-45. - Landmark study establishing reduction quality thresholds (<1mm = 88% good outcome) 2. **Letournel E, Judet R** (1993). *Fractures of the Acetabulum*. 2nd ed. Berlin: Springer-Verlag. - Definitive classification and surgical approach atlas 3. **Keith JE Jr, Brashear HR Jr, Guilford WB** (1988). Stability of posterior fracture-dislocations of the hip. Quantitative assessment using computed tomography. *J Bone Joint Surg Am* 70(5):711-14. - Established 40% posterior wall threshold for instability 4. **Vailas JC, Hurwitz S, Wiesel SW** (1989). Posterior acetabular fracture-dislocations: fragment size, joint capsule, and stability. *J Trauma* 29(11):1494-96. - Dynamic stress testing methodology for borderline cases 5. **Kreder HJ, et al** (2006). Determinants of functional outcome after simple and complex acetabular fractures involving the posterior wall. *J Bone Joint Surg Br* 88(6):776-82. - Identified marginal impaction as key predictor of poor outcome 6. **Matta JM, Tornetta P 3rd** (2000). Internal fixation of unstable pelvic ring injuries. *Clin Orthop Relat Res* (329):129-140. - Surgical technique refinements and outcomes 7. **Brooker AF, et al** (1973). Ectopic ossification following total hip replacement. Incidence and a method of classification. *J Bone Joint Surg Am* 55(8):1629-32. - Classification system still used today 8. **Burd TA, et al** (2001). Heterotopic ossification prophylaxis with indomethacin increases the risk of long-bone nonunion. *J Bone Joint Surg Br* 83(5):651-54. - Caution with concomitant long-bone fractures

Acetabular Fracture ORIF - Posterior Wall

Acetabular Fracture ORIF - Posterior Wall