import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' **Location**: Exits pelvis through greater sciatic notch inferior to piriformis, courses 2cm posterior to hip capsule at joint level, descends along posterior thigh. **Protection**: Early identification through scar tissue, vessel loop isolation, protected retractor placement, stay anterior if nerve not found, avoid excessive traction (lengthening >2cm increases palsy risk exponentially) **Location**: Exits pelvis ABOVE piriformis through greater sciatic notch, courses along gluteus medius undersurface, enters muscle belly 3-5cm superior to greater trochanter tip. **Protection**: Limit proximal dissection to <5cm above GT, stay below medius muscle belly, avoid superior retractor placement beyond safe zone **Location**: Femoral triangle 2-3cm anterior to anterior hip capsule. Lateral to medial: Nerve-Artery-Vein (NAV mnemonic). **Protection**: Anterior approach requires careful identification and retraction, avoid medial cup screws in anteroinferior quadrant (vessels at risk), fluoroscopy for screw depth verification **Location**: Iliac vessels lie on inner pelvic wall, vulnerable to medial cup screw penetration. **Protection**: Anteroinferior quadrant screws AVOIDED (highest vessel risk), medial wall perforation avoided during reaming, fluoroscopy or navigation to verify screw length, posterosuperior quadrant safest for screws **Location**: Course along obturator foramen inferiorly at level of ischium. **Protection**: Avoid inferior cup screws directed toward obturator foramen, careful during inferior reaming near teardrop, ischial screws directed posteriorly (not inferiorly through foramen) ## Comprehensive Assessment ### Infection Exclusion (MANDATORY) **Clinical Assessment** - Pain pattern: constant pain at rest suggests infection (vs activity-related pain in aseptic loosening) - Constitutional symptoms: fevers, chills, night sweats (infection) - Wound history: prior drainage, dehiscence, delayed healing - Risk factors: diabetes, immunosuppression, prior infection **Laboratory Investigation** - ESR: >30mm/hr concerning but nonspecific (also elevated in inflammation, malignancy) - CRP: >10mg/L concerning, more responsive than ESR - **CRITICAL**: ESR/CRP alone have 30% false negative rate - INADEQUATE for ruling out infection **Joint Aspiration (GOLD STANDARD)** - Cell count: >3000 cells/µL highly suggestive of infection (acute), >1100 in chronic - Differential: >80% PMNs highly specific for infection - Culture: MUST hold 14 days for slow-growing organisms (Cutibacterium acnes common in shoulder, can occur in hip) - Alpha-defensin: 97% sensitivity, 96% specificity (rapid point-of-care test) - Synovial fluid CRP: >9.5mg/L or IL-6 >12,000pg/mL suggestive **Advanced Testing if Equivocal** - Repeat aspiration if initial non-diagnostic - Nuclear medicine: Indium-111 WBC scan (90% sensitivity), FDG-PET - Tissue cultures at surgery: 5-6 samples from interface, 14-day culture - Sonication of explanted components (increases culture yield) ### Radiographic Assessment **Standard X-rays** - AP pelvis: assess acetabular bone loss, superior migration, Kohler line - Lateral hip: assess cup version, anterior/posterior column integrity - Full femur if long-standing loosening: assess diaphyseal bone quality **Paprosky Acetabular Classification** - Type I: Intact rim, intact columns, <2mm superior migration → Standard cup - Type IIA: Intact rim, intact columns, 2-3cm superior migration → Jumbo cup - Type IIB: Superior/posterior rim deficiency, >3cm migration → Augments + cup - Type IIC: Medial wall osteolysis, intact rim → Bone graft + cup - Type IIIA: Rim loss but ischium/teardrop intact → Jumbo cup OR cup-cage - Type IIIB: Severe rim loss, ischium/teardrop gone, Kohler line discontinuous → Custom triflange OR complex reconstruction **Paprosky Femoral Classification** - Type I: Minimal metaphyseal damage, intact diaphysis → Primary stem - Type II: Damaged metaphysis, intact diaphysis >4cm → Extensively coated stem - Type IIIA: Severe metaphyseal damage, intact diaphysis >4cm, expanded canal → Extensively coated OR modular tapered - Type IIIB: Metaphyseal AND proximal diaphyseal damage, <4cm intact diaphysis → Long extensively coated OR modular tapered - Type IV: Extensive damage, no diaphyseal fixation possible → Megaprosthesis OR allograft-prosthesis composite **Advanced Imaging** - CT with 3D reconstruction: Better defines bone defects, aids implant planning (especially Paprosky III defects) - MARS MRI: Soft tissue assessment if metal artifact reduction needed (abductor quality, muscle atrophy) ### Implant Planning **Acetabular Options Based on Paprosky** - Type I/IIA: Standard uncemented hemispherical cups (multiple sizes), jumbo cups (66-80mm) - Type IIB/IIC: Porous metal augments (trabecular tantalum or titanium), structural allografts - Type IIIA/IIIB: Antiprotrusio cages (Burch-Schneider), custom triflange implants, oblong cups **Femoral Options Based on Paprosky** - Type I/II: Standard primary stems, extensively coated stems (6-10 inch coating lengths) - Type IIIA/IIIB: Modular tapered fluted stems (Wagner SL), long extensively coated stems - Type IV: Proximal femoral replacement (megaprosthesis), allograft-prosthesis composite **Adjuncts and Fixation** - Morselized allograft for impaction grafting - Cortical strut grafts for defects/perforations - Screws (multiple sizes 3.5-6.5mm, lengths 25-70mm) - Cerclage wires (16-18 gauge) or cables for ETO/fractures ### Blood Management **Preoperative Optimization** - Hemoglobin optimization: target >120g/L, iron supplementation if anemic (ferritin <30µg/L) - Erythropoietin if severe anemia and time permits (3-4 weeks preop) - Discontinue anticoagulation per protocol (warfarin 5 days, DOACs 2-3 days) **Intraoperative Strategies** - Cell saver (can reduce transfusion by 30-50%) - Tranexamic acid: 15-20mg/kg IV at induction, repeat at 3 hours (reduces blood loss 30-50%) - Meticulous hemostasis, hypotensive anesthesia if appropriate **Transfusion Planning** - Type and cross 2-4 units (transfusion rate 30-50% in revision) - Restrictive threshold: Hb <70g/L or <80g/L with symptoms **EXAM KEY**: "Before ANY revision, infection MUST be ruled out - aspiration is GOLD STANDARD: cell count >3000, PMN >80%, 14-day culture. ESR/CRP alone inadequate (30% false negative). Alpha-defensin excellent (97% sensitivity/96% specificity). If infected, management completely different - 2-stage revision mandatory. For aseptic loosening, I classify bone loss using PAPROSKY CLASSIFICATION - guides reconstruction strategy. ACETABULAR: I/IIA = standard/jumbo cup, IIB/IIC = augments + cup, IIIA/IIIB = complex reconstruction (cage, triflange, allograft). FEMORAL: I = primary stem, II/IIIA = extensively coated for diaphyseal fixation (bypass metaphyseal defects), IIIB = long stem, IV = megaprosthesis OR APC. I template extensively, order multiple implant sizes and backup options." ## Approach and Exposure ### Previous Incision Utilization **Rationale for Using Previous Incision** - Preserves soft tissue vascularity (reduces wound complications) - Minimizes additional soft tissue trauma - Avoids creating new tissue planes - If multiple previous incisions: choose most posterior for posterior approach access **Incision Technique** - Elliptical excision of old scar with 1-2mm margins to healthy dermis - Assess skin quality: thin scarred skin = higher dehiscence risk - Extend proximally toward PSIS for acetabular access - Extend distally along femoral shaft for femoral access - Total length typically 18-25cm (vs 10-15cm for primary) ### Deep Dissection **Fascia Lata** - Incise in line with previous surgery - May be thickened and scarred - Extend incision to match skin incision length **Gluteus Maximus Split** - Split in line with fibers (true internervous plane) - Planes often difficult to identify in scar tissue - Work patiently with sharp dissection - Avoid blunt dissection (tears tissue, increases bleeding) **Scar Release** - Extensive scar release usually required - Capsule thick, contracted, adherent to surrounding structures - Sharp dissection to release adhesions - Short external rotators often absent or severely atrophic ### Sciatic Nerve Identification (CRITICAL) **Importance in Revision** - Nerve palsy risk 2-5% in revision (vs 0.5-2% primary) - Risk factors: scar encasement, traction from lengthening, direct trauma, thermal injury **Identification Technique** - Palpate nerve posterior to hip capsule - May need to dissect nerve from scar tissue - Place vessel loop or protected retractor for identification - If nerve cannot be clearly identified: proceed cautiously, stay anterior to expected location **Protection Strategies** - Protected retractors (Hohmann with sleeve) - Avoid excessive traction - Limit lengthening to <2cm (nerve palsy risk increases exponentially >2cm) - Careful with burr near posterior cortex (thermal injury) **EXAM KEY**: "I use previous incision - excise scar elliptically to healthy dermis, extend as needed (typically 18-25cm for revision). Extensive scar release almost always needed - normal tissue planes obliterated by fibrosis. I identify SCIATIC NERVE EARLY - this is CRITICAL as nerve palsy risk 2-5% in revision (vs 0.5-2% primary) due to scar encasement, traction from lengthening, and difficult dissection. I dissect nerve from scar tissue carefully, place vessel loop for protection. If nerve not clearly identified, proceed very cautiously staying anterior to expected location. Adequate exposure essential - cannot rush or will have inadequate access for safe component removal and reconstruction." ## Acetabular Component Removal ### Liner Removal - Grasp modular liner with extractor or osteotome - Remove to expose acetabular bone stock - Assess liner wear pattern (eccentric = malposition or impingement) ### Cup Removal Techniques **Loose Cup (Gross Instability)** - Often levers out with curved osteotomes - Stay on metal to preserve bone - May extract easily with manual pressure **Well-Fixed Cup (Partial Loosening)** - Insert curved osteotomes between cup and bone around ENTIRE circumference - Stay ON METAL (not bone) - bone preservation paramount - Work sequentially, gentle tapping - Specialized extraction tools if needed (Explant system with slap hammer) **Screw Removal** - Remove accessible screws from outer surface - Cut off inside cup if threads stripped - May need to burr screw heads **Cemented Cup (Less Common)** - Remove cement with high-speed burr - Flexible osteotomes - Ultrasonic cement removal tools - Painstaking and time-consuming ### Osteolysis Curettage (CRITICAL) **Materials to Remove** - Polyethylene wear debris (gray/white rubbery) - Granulation tissue and pseudomembrane (soft friable) - Metal debris if metal-on-metal (black staining) - Cement debris (white PMMA fragments) - Necrotic bone (sequestered fragments) **Technique** - Curette ALL osteolytic cavities to bleeding bone - Power burr to remove pseudomembrane lining - Residual debris continues osteolysis → early failure - Copious pulsatile lavage: 3-6 liters saline ### Bone Loss Assessment **Anatomic Landmarks** - Obturator foramen: inferior reference - Teardrop: medial reference - Ischium: posteroinferior reference - Anterosuperior rim: superior reference **Measurements** - Superior migration: vertical distance from anatomic hip center - Rim integrity: intact vs deficient (location and extent) - Column integrity: anterior and posterior columns intact vs fractured - Medial wall: intact vs perforated vs osteolytic **Final Classification** - Confirm Paprosky classification - Often worse than preoperative imaging - Determines reconstruction strategy - Excessive bone loss during cup removal (MOST CRITICAL) - worsens Paprosky classification, may make reconstruction impossible - Acetabular wall fracture (especially posterior wall) - may need plating or cage - Intrapelvic perforation if medial wall deficient - vascular/visceral injury risk - Sciatic nerve injury if breach posterior column - Incomplete debris removal - persistent osteolysis causes early failure - Unrecognized pelvic discontinuity (fracture between superior and inferior hemipelvis) - will fail without specific reconstruction (plating or cage) ## Femoral Component Removal ### Cemented Stem Removal **Loose Cemented Stem** - Apply traction with extraction device - Gentle twisting - Stem comes out leaving cement mantle **Well-Fixed Cemented Stem** - DO NOT attempt forceful extraction (femoral fracture guaranteed) - Cement-within-cement technique if cement mantle intact and bone stock good (Paprosky I only) - controversial **Cement Removal Techniques** 1. **Flexible Osteotomes** - Insert between cement and bone - Work proximal to distal - Gentle tapping - Risk: femoral perforation if penetrate into bone 2. **High-Speed Burr** - Carefully burr cement in quadrants working distally - CONTINUOUS irrigation (prevents heat necrosis) - Stay in cement, not bone - Risks: heat necrosis, perforation, thermal nerve injury 3. **Ultrasonic Cement Removal** - Ultrasonic frequency disrupts cement-bone interface - Safer than burr but slower - Requires specialized equipment 4. **Distal Cement Plug** - Often most difficult part - May need femoral cortical window (2-3cm) for access - Repair window with cerclage wire and strut graft ### Extended Trochanteric Osteotomy (ETO) **Indications** - Well-fixed cementless stem - Extensively coated stem (large surface area ingrowth) - Cemented stem with inaccessible distal cement - Need for distal femoral access for cement/osteolysis **Technique** - Mark osteotomy line 10-12cm long starting 1-2cm proximal to GT tip - Use microsagittal saw to cut ANTERIOR 1/3 of circumference - Preserves posterior periosteal blood supply - Leave GT ATTACHED to vastus lateralis sleeve (maintains blood supply) - Complete osteotomy with osteotomes - Reflect GT anterolaterally with attached muscle **Advantages** - Excellent access to femoral canal - Preserves bone stock - Can be repaired reliably **Repair** - 2-3 cerclage wires or cables - Optional lag screws if bone quality good - Consider strut graft reinforcement - Protected weight bearing 6-12 weeks ### Cementless Stem Removal **Loose Cementless Stem** - Extracts easily with extraction device - Apply axial traction with rotation **Well-Fixed Cementless Stem** - ETO MANDATORY - Do not force (will fracture femur) - Never attempt forceful extraction of well-fixed cementless stem ### Femoral Osteolysis Management **Identification** - All osteolytic lesions identified - May need cortical windows for access **Curettage** - Thorough curettage to bleeding bone - Remove all debris (wear particles, pseudomembrane) - Copious lavage **Final Assessment** - Metaphyseal bone loss extent - Diaphyseal bone quality - Isthmus preserved or expanded - Cortices intact or thinned - Finalize Paprosky femoral classification **EXAM KEY**: "Femoral component removal MOST CHALLENGING step. CEMENTED STEM: Loose stem may extract leaving cement. Cement removal: flexible osteotomes, high-speed burr (CAREFUL - heat necrosis risk, perforation 1-5%), or ultrasonic tools. Work proximal to distal, continuous irrigation. Distal cement plug may need cortical window. WELL-FIXED CEMENTLESS STEM: I use ETO - NEVER force extraction or will fracture. ETO: anterior 1/3 of femur for 10-12cm, GT stays attached to vastus lateralis, excellent access, repair with cerclage wires. After removal, I curette ALL osteolysis to bleeding bone. Femoral perforation risk 1-5% during cement removal - treat with strut graft and cerclage wire." ## Acetabular Reconstruction ### Type I (Standard Cup) - **Defect**: Intact rim, intact columns, <2cm superior migration - **Strategy**: Standard uncemented hemispherical cup - **Technique**: Ream to bleeding bone, underream 1-2mm, press fit, screws if needed - **Goal**: Adequate press fit for ingrowth ### Type IIA (Jumbo Cup or Elevated Center) - **Defect**: Intact rim, intact columns, 2-3cm superior migration - **Strategy**: Jumbo cup (66-70mm, 2-4mm larger than native) OR elevated hip center - **Technique**: Jumbo cup preferred (restores anatomy), underream 2mm, multiple screws - **Goal**: Contact healthy bone superiorly and inferiorly ### Type IIB (Augments + Cup) - **Defect**: Superior/posterior rim deficiency, >3cm superior migration - **Strategy**: Porous metal augments to fill segmental defects + hemispherical cup - **Technique**: Screw augments to pelvis (ilium/ischium), ream remaining bone, place cup with screws - **Goal**: Convert segmental to contained defect, restore hip center ### Type IIC (Medial Graft + Cup) - **Defect**: Medial wall osteolysis, intact rim - **Strategy**: Bone graft + cup - **Technique**: Pack morselized allograft into medial defect, medial mesh or augment if large, standard cup with screws - **Goal**: Restore medial wall, avoid medial penetration ### Type IIIA (Jumbo Cup OR Cup-Cage) - **Defect**: Rim loss but ischium and teardrop intact, <3cm superior migration - **Options**: 1. Jumbo cup (70-80mm) to contact ischium/ilium, 6-8 screws 2. Cup-cage construct (cage for structure, cup for articulation) 3. Augments + large cup - **Goal**: 40-50% host bone contact, structural support ### Type IIIB (Custom Triflange OR Complex Reconstruction) - **Defect**: Severe rim loss, ischium/teardrop gone, >3cm migration, Kohler line discontinuous - **Options**: 1. Custom triflange (patient-specific, best fixation, 3-6 month lead time) 2. Cup-cage + augments + structural allograft 3. Oblong trabecular metal cup - **Goal**: Stable construct despite massive bone loss ### Reconstruction Principles **Biological Fixation** - Ream to bleeding subchondral bone - 40-50% host bone contact minimum - Porous coating for ingrowth (trabecular metal, titanium mesh) **Mechanical Fixation** - Underream 1-2mm for press fit - Multiple screws in safe zones (posterosuperior quadrant safest) - Avoid: anteroinferior (iliac vessels), medial (intrapelvic), inferior (obturator nerve) **Anatomic Restoration** - Restore hip center of rotation when possible - Lewinnek safe zone: 40-45° inclination, 15-20° anteversion - Better biomechanics, less leg length discrepancy, reduced dislocation risk - Cup migration/loosening if <40% host bone contact - early failure within 2-5 years - Instability if center of rotation not restored or cup malpositioned - Screw penetration medially - intrapelvic, vascular (iliac vessels) or nerve (obturator) injury - Cage failure if inadequate screw fixation - catastrophic construct failure - Unrecognized pelvic discontinuity - standard cup will fail, requires plating or cage across discontinuity - Excessive cup anteversion or retroversion - instability despite good fixation ## Femoral Reconstruction ### Type I (Primary Stem) - **Defect**: Minimal metaphyseal damage, intact diaphysis, good bone stock - **Strategy**: Standard primary stem (cemented or cementless) - **Technique**: Same as primary THR - **Fixation**: Metaphyseal or proximal ### Type II (Extensively Coated Stem) - **Defect**: Damaged metaphysis, intact diaphysis >4cm - **Strategy**: Extensively coated cementless stem (6-8 inches coating) - **Technique**: Bypass metaphyseal defects, achieve 2cm distal diaphyseal scratch fit, progressive reaming, 0.5-1mm interference fit - **Fixation**: Diaphyseal (bypass metaphyseal defects by 2 cortical diameters) ### Type IIIA (Extensively Coated Long OR Modular Tapered) - **Defect**: Severe metaphyseal damage, intact diaphysis >4cm, expanded canal - **Options**: 1. Extensively coated long stem (8-10 inches coating) 2. Modular tapered fluted stem (Wagner SL) - proximal body + distal taper - **Technique**: Achieve 2cm distal fixation, may impaction graft metaphysis with morselized allograft - **Fixation**: Distal diaphyseal ### Type IIIB (Very Long Extensively Coated OR Long Modular Tapered) - **Defect**: Severe metaphyseal AND proximal diaphyseal damage, <4cm intact diaphysis - **Options**: 1. Very long extensively coated stem (10-12 inches) 2. Long modular tapered fluted stem extending well into distal diaphysis - **Technique**: Find adequate distal fixation (may need 4cm of diaphysis distally) - **Fixation**: Distal diaphyseal bypass ### Type IV (Megaprosthesis OR Allograft-Prosthesis Composite) - **Defect**: Extensive metaphyseal and diaphyseal damage, no adequate diaphysis for fixation - **Options**: 1. **Proximal Femoral Replacement (Megaprosthesis)** - Uncemented distal stem (150-200mm) into remaining diaphysis - Modular proximal articulation - Reattach abductors to collar - ADVANTAGES: Immediate stability, bypasses unfixable bone loss - DISADVANTAGES: Abductor dysfunction common, higher dislocation risk 2. **Allograft-Prosthesis Composite (APC)** - Structural proximal femur allograft - Stem cemented through allograft and into host bone - Allograft-host junction fixation with plate or cables - ADVANTAGES: Bone stock restoration for future revisions - DISADVANTAGES: Allograft union takes 12-18 months, non-union risk 10-20% ### Adjunctive Techniques **Impaction Grafting** - Morselized allograft bone graft impacted into femoral canal - Restores bone stock, augments fixation - Requires intact cortices (wire mesh if cortical defects) **Cortical Strut Grafts** - Onlay cortical allograft struts (2-3 struts around femur) - Indications: cortical defects, perforations, prophylactic fracture prevention, ETO reinforcement - Fix with cerclage wires or cables (3-4 per strut) **EXAM KEY**: "Femoral reconstruction guided by PAPROSKY: Type I = standard primary stem. Type II = EXTENSIVELY COATED stem for diaphyseal fixation - 6-8 inch coating, 2cm distal scratch fit, bypass defects by 2 cortical diameters (typically 10-15cm stem). Type IIIA = extensively coated long stem OR modular tapered stem (Wagner SL) - can impaction graft metaphysis. Type IIIB = very long extensively coated OR long modular tapered. Type IV = MEGAPROSTHESIS (immediate stability, reattach abductors) OR allograft-prosthesis composite (bone restoration but slower recovery, non-union risk 10-20%). I use STRUT GRAFTS for cortical defects, perforations, or ETO reinforcement - 2-3 onlay struts with cerclage wires. GOAL: stable distal fixation, restore offset and length." ## Trial Reduction and Stability ### Comprehensive Stability Testing **Posterior Stability (Most Critical)** - 90° flexion + maximal adduction + maximal internal rotation - Most common dislocation direction (70-80% after revision) - Hip should be stable throughout **Anterior Stability** - Full extension + 40° external rotation + slight adduction - Should be stable **Superior Escape** - Abduction + external rotation - Rare but check if cup highly inclined **Range of Motion Assessment** - Flexion: 110-120° (sitting) - Extension: to neutral (lying flat) - Abduction: 45° (getting out of car) - Adduction: to midline (crossing legs if allowed) - Internal rotation: 30° (tying shoes) - External rotation: 40° (putting on socks) **Impingement Assessment** - Look and feel for prosthetic impingement at extremes - Femoral neck contacts acetabular cup or liner rim - Causes: edge loading, liner damage, squeaking, instability, accelerated wear - If present: modify positions, change neck length, increase offset, different head size **Soft Tissue Tension** - Reduction should be snug but not overly tight - Excessive tension increases nerve palsy risk - Knee heights equal = leg lengths equal **Fluoroscopic Confirmation** - AP view: cup inclination 40-45°, head centered - Lateral view: cup version 15-20° - Femoral stem: neutral alignment, appropriate depth - Leg length: lesser trochanters symmetric height ### Management of Instability **If Unstable During Trialing** - Reposition cup (more anteversion if posterior instability, less if anterior) - Change femoral stem version - Increase head size (36mm to 40mm reduces dislocation) - Increase offset (higher offset increases soft tissue tension) - Constrained liner if severe instability despite optimization - Dual mobility cup (best option for high-risk instability) **Leg Length Management** - Aim <1cm discrepancy - Adjust femoral component depth or change neck length - Avoid >2cm lengthening (nerve palsy risk increases exponentially) **Critical Decision Point** - MUST NOT proceed to final components if unstable during trialing - Will guarantee failure post-operatively ## Final Implantation and Closure ### Final Component Sequence **Acetabular** - Clean liner seating surface - Insert final liner (verify fully seated) - Dual mobility: insert inner bearing into outer bearing - Constrained liner: prepare for head locking **Femoral** - CEMENTLESS: Clean canal, ensure dry, insert stem with gentle impaction, fluoroscopy confirmation - CEMENTED: Cement restrictor distally, retrograde gun fill proximal to distal, pressurize, insert stem, hold 8-10 minutes **Femoral Head** - Clean femoral taper thoroughly (prevents fretting corrosion) - Dry taper - Apply firm impaction (head MUST be fully seated) - For constrained liner: engage locking mechanism, verify locked **Final Checks** - Reduce hip with final components - Repeat stability testing (should be identical to trials) - Final fluoroscopy (document positions, exclude fractures) ### ETO Repair (If Performed) **Fixation Technique** - Reduce GT fragment anatomically - 2-3 cerclage wires or cables (proximal, mid, distal) - Optional supplemental lag screws if bone quality good - Consider strut graft reinforcement if osteopenic **Post-op Protocol** - Protected weight bearing (touch-down or partial) 6-12 weeks - Avoid abductor-stressing activities until healed - Radiographic union before full weight bearing ### Soft Tissue Reconstruction **Abductor Repair** - If detached: repair gluteus medius/minimus to GT with transosseous sutures or anchors - If poor quality: advancement or allograft augmentation - If completely deficient: counsel regarding Trendelenburg gait **Capsular Repair** - Repair if tissue adequate and of good quality - Reduces posterior dislocation by 50-70% - Often too diseased to repair in revision for loosening **Other Repairs** - Short external rotators to posterior capsule or GT - Vastus lateralis reattached to femur - Strut grafts verified secure with cerclage wires ### Wound Closure **Irrigation** - Copious pulsatile lavage: 3-6 liters normal saline - Remove all debris, blood clots, bone fragments **Hemostasis** - Meticulous with electrocautery and ties - Topical hemostatic agents if persistent oozing - Consider drain if large dead space (remove 24-48 hours) **Layered Closure** - Deep drain if used (10-French, separate stab incision) - Gluteus maximus fascia: #1 absorbable suture (strength layer) - Subcutaneous: 2-0 or 3-0 absorbable (eliminate dead space) - Deep dermal: 3-0 or 4-0 absorbable (reduce skin tension) - Skin: staples (most common), subcuticular absorbable, or interrupted non-absorbable **Dressing** - Sterile absorbent dressing - Consider negative pressure wound therapy if high-risk wound **Abduction Pillow** - Place 15-20° abduction pillow immediately - Prevents adduction (most common dislocation position) - Stays continuously for 6 weeks ## Post-operative Management ### Immediate Post-op Orders **Antibiotics** - Continue IV antibiotics 24-48 hours total perioperative - Cefazolin 2g q8h or vancomycin 15mg/kg q12h if MRSA risk - Discontinue if no contamination/infection **Anticoagulation (CRITICAL)** - LMWH: enoxaparin 40mg SC daily (start 12-24 hours post-op) - DOAC: rivaroxaban 10mg PO daily (start 6-10 hours post-op) OR apixaban 2.5mg PO BID (start 12-24 hours post-op) - Duration: 4-6 weeks minimum (longer than primary due to prolonged recovery) - Mechanical prophylaxis: TED stockings, sequential compression devices **Pain Control** - Multimodal analgesia - Paracetamol 1g q6h scheduled - NSAIDs if not contraindicated (celecoxib 200mg PO BID) - Opioids prn for breakthrough (minimize use) - Regional anesthesia if available **Transfusion** - Check hemoglobin 6-12 hours post-op - Transfuse if Hb <70g/L or <80g/L with symptoms - Each unit should raise Hb by 10g/L **Monitoring** - Frequent neurovascular checks (foot dorsiflexion, plantar flexion, sensation, pulses) - Document baseline exam immediately post-op - Any new deficit requires immediate investigation **Imaging** - Post-op X-rays (AP pelvis, lateral hip) within 24-48 hours - Document component positions, exclude fractures, establish baseline ### Early Mobilization (Days 1-5) **Weight Bearing Status** - WBAT: If components well-fixed, no ETO, no strut grafts, no fractures - TDWB/PWB 20kg: If ETO performed, strut grafts used, questionable fixation, intraoperative fracture - NWB: Rare, only if unstable construct **Gait Training** - Walker or crutches for 6-12 weeks - Progress from walker to single crutch to cane to independent **Hip Precautions (Posterior Approach)** - STRICT for 12 weeks (longer than primary 6 weeks) - No hip flexion >90° (elevated toilet seat, no bending forward) - No adduction past midline (no crossing legs, abduction pillow in bed) - No internal rotation (no pivoting on operative leg) - Sleep supine or on operative side with pillow between legs **Discharge Criteria (3-5 days)** - Pain controlled on oral medications - Medically stable - Safe mobilization with assistive device - Adequate social support or accepting rehab transfer - Follow-up arranged, education provided **EXAM KEY**: "Stability testing after revision CRITICAL - dislocation rate 10-15% vs 2-5% primary. I test: (1) Posterior (90° flex + IR + adduction - most common), (2) Anterior (extension + ER), (3) Full ROM stable, (4) Impingement (neck hitting cup causes instability). Fluoroscopy: confirm cup 40-45° inclination, 15-20° anteversion, head centered, leg lengths equal. If UNSTABLE: I must address - reposition cup, change version, increase head size, increase offset, consider constrained liner or dual mobility. Will NOT proceed to final components if unstable - guarantees failure. Closure: copious irrigation (3-6L), meticulous hemostasis, layered closure, ABDUCTION PILLOW immediately. Post-op: Antibiotics 24-48hr, DVT prophylaxis CRITICAL (LMWH or DOAC for 4-6 weeks), multimodal analgesia, frequent neuro checks." ## References 1. Paprosky WG, Perona PG, Lawrence JM. Acetabular defect classification and surgical reconstruction in revision arthroplasty: a 6-year follow-up evaluation. *J Arthroplasty*. 1994;9(1):33-44. **Seminal paper establishing Paprosky acetabular classification system - gold standard for describing bone loss and guiding reconstruction strategy in revision hip surgery.** 2. Della Valle CJ, Paprosky WG. The femur in revision total hip arthroplasty: evaluation and classification. *Clin Orthop Relat Res*. 2004;(420):55-62. **Definitive description of Paprosky femoral classification (Types I-IV) based on metaphyseal and diaphyseal bone loss - determines femoral reconstruction strategy.** 3. Parvizi J, Tan TL, Goswami K, et al. The 2018 Definition of Periprosthetic Hip and Knee Infection: An Evidence-Based and Validated Criteria. *J Arthroplasty*. 2018;33(5):1309-1314. **International consensus definition for diagnosing periprosthetic joint infection - provides scoring system incorporating aspiration cell count, differential, alpha-defensin, and culture results.** 4. Younger TI, Bradford MS, Magnus RE, Paprosky WG. Extended proximal femoral osteotomy: a new technique for femoral revision arthroplasty. *J Arthroplasty*. 1995;10(3):329-338. **Original description of extended trochanteric osteotomy (ETO) technique - controlled anterior osteotomy preserving posterior blood supply, enables safe removal of well-fixed cementless stems.** 5. Sporer SM, Paprosky WG. Acetabular revision using a trabecular metal acetabular component for severe acetabular bone loss associated with a pelvic discontinuity. *J Arthroplasty*. 2006;21(6 Suppl 2):87-90. **Management of pelvic discontinuity in revision hip surgery - trabecular metal cups with or without cage constructs for massive acetabular defects.** 6. Chen AF, Hozack WJ. Component optimization in revision total hip arthroplasty. *Orthop Clin North Am*. 2014;45(2):161-167. **Comprehensive review of implant selection for revision hip arthroplasty based on bone loss - extensively coated stems, modular tapered stems, trabecular metal cups, augments, and cages.** 7. Younger AS, Duncan CP, Masri BA. Surgical exposures in revision total hip arthroplasty. *J Am Acad Orthop Surg*. 1997;5(1):55-64. **Detailed surgical approach options for revision hip surgery - extended posterolateral approach, trochanteric slide, extended trochanteric osteotomy, and management of prior surgical approaches.** 8. Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). *Hip, Knee & Shoulder Arthroplasty: 2023 Annual Report*. Adelaide: AOA; 2023. **Australian registry data showing revision hip arthroplasty outcomes: 10-year cumulative percent revision 8.4% for aseptic loosening revisions, higher dislocation rate than primary (3.2% vs 1.1% at 1 year).** 9. Lachiewicz PF, Soileau ES. Changing indications for revision total hip arthroplasty. *J Surg Orthop Adv*. 2005;14(2):82-84. **Evolution of revision hip indications over time - aseptic loosening declining due to improved implants, polyethylene wear and osteolysis now leading indications, infection remains 15-20% of revisions.** 10. Masri BA, Meek RM, Duncan CP. Periprosthetic fractures evaluation and treatment. *Clin Orthop Relat Res*. 2004;(420):80-95. **Comprehensive review of periprosthetic femoral fractures in revision hip surgery - Vancouver classification system, treatment algorithms based on fracture location and component stability, role of strut grafts and cerclage wires.**

Revision Total Hip Replacement for Aseptic Loosening

Revision Total Hip Replacement for Aseptic Loosening