import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' **Exits greater sciatic notch 4-5cm above greater trochanter tip**. Limit gluteus medius split to 5cm from GT. Injury = permanent Trendelenburg gait, abductor weakness. ETO approach avoids this entirely. **3-4cm posterior to hip joint**. At risk with posterior approach, excessive retraction, leg lengthening >4cm. Document pre-op function. Post-op palsy 2-5% in revision. **Medial to acetabulum anteriorly**. At risk with anterior retractor slippage, aggressive acetabular preparation. Keep retractor ON bone at all times. Catastrophic hemorrhage if injured. **Proximal femur fracture 5-10%** with extraction of well-fixed stems. Use ETO for cementless stems. Prophylactic cerclage if osteopenic. Never lever against cortex. ### Definite Indications - **Chronic PJI** (>4 weeks symptoms) with positive MSIS criteria - **Failed DAIR** (Debridement, Antibiotics, Implant Retention) - **Difficult-to-treat organisms**: MRSA, resistant Gram-negatives, fungi - **Culture-negative PJI** where organism unknown - **Failed one-stage revision** ### Consider One-Stage Instead - Known sensitive organism (pre-op cultures) - Healthy soft tissue envelope - Good bone stock - Non-immunocompromised patient - Gram-positive sensitive organism ### DAIR May Be Appropriate If - Acute infection (<3-4 weeks symptoms) - Stable, well-fixed implants - Healthy patient - Known sensitive organism - Modular components exchangeable ### Infection Workup (ESSENTIAL) - **Aspiration** (off antibiotics 2+ weeks) - send for: - Cell count and differential (WBC >3000, PMN >80%) - Gram stain - Culture (aerobic, anaerobic, fungal, AFB) - Crystal analysis (rule out gout) - **Serum markers**: ESR, CRP, WBC (ESR >30, CRP >10 supports PJI) - **Nuclear imaging**: WBC-labelled scan if diagnosis uncertain ### Imaging Assessment - **Plain radiographs**: Component position, loosening, bone loss, periosteal reaction - **CT scan**: Assess bone stock, plan reconstruction, identify collections - **Component identification**: Know manufacturer, size, extraction equipment needed ### Medical Optimization - **Nutrition**: Albumin >3.0, transferrin >200, lymphocytes >1500 - **Diabetes**: HbA1c <8%, glucose control - **Immunosuppression**: Hold if possible, infectious disease consult - **Anticoagulation**: Cease appropriately, bridge if needed ### Surgical Planning - Use **previous approach** (posterior most common) - Plan for **ETO** if stem well-fixed (have equipment ready) - **Blood availability**: Cross-match 4 units (high blood loss expected) - **ICU bed** if medically complex patient ### Procedure-Specific Risks - **Persistent infection requiring repeat procedures** (10-20%) - **Spacer dislocation** (10-20%) - may need revision or brace - **Spacer fracture** (5-10%) - **Intraoperative femur/acetabular fracture** (5-10%) - **Sciatic nerve injury** (2-5%) - usually neuropraxia - **Wound complications** (5-15%) - **Need for Girdlestone** (5-10%) if infection cannot be controlled ### Realistic Expectations - Stage 1 = temporizing procedure, NOT definitive - 8-12 weeks with spacer in situ - Limited mobility, toe-touch weight bearing - IV antibiotics for 6 weeks (PICC line) - May need antibiotic holiday before stage 2 - Stage 2 success rate 85-95% if criteria met ### Alternative Treatments Discussed - DAIR (if acute, stable implants, sensitive organism) - One-stage revision (strict criteria rarely met) - Chronic suppressive antibiotics (palliation) - Resection arthroplasty (Girdlestone) if not surgical candidate - Above-knee amputation (rare, life-threatening sepsis) ### Spacer Materials - **Antibiotic cement**: Palacos preferred (better elution), 2-3 × 40g packs - **Vancomycin powder**: 4-6g - **Tobramycin powder**: 3.6g (or Gentamicin 2g) - **Articulating spacer mould**: Modular head sizes (22mm, 28mm, 32mm available) - **Steinmann pins**: For spacer reinforcement if making hand-moulded ### Extraction Equipment - **Universal extraction set**: Curved osteotomes, slap hammers - **High-speed burr**: For cement removal - **Ultrasonic cement removal**: If available (Midas Rex) - **Extended trochanteric osteotomy set**: Oscillating saw, cables, plates - **Cerclage wire/cables**: For prophylactic protection or fracture fixation ### General Equipment - **Pulsatile lavage**: 9L minimum (3-6L debridement, 3L final) - **Tissue sampling supplies**: 5+ containers for separate tissue samples - **Drains**: 2 deep drains minimum - **VAC dressing**: If wound concern or repeat procedures planned ### Step 1: Intraoperative Tissue Sampling (BEFORE Antibiotics) **CRITICAL**: Obtain cultures BEFORE prophylactic antibiotics given. Hold antibiotics until 5+ tissue samples obtained. Take **minimum 5 separate tissue samples** from: 1. Pseudocapsule (3 samples from different locations) 2. Interface membrane around acetabular component 3. Interface membrane around femoral component 4. Any obvious purulent collections 5. Synovial fluid aspiration Each sample in **separate sterile container**. Send for aerobic, anaerobic, fungal, and AFB culture. Request prolonged culture (14 days for low-virulence organisms). **FRCS KEY**: 5+ samples increases sensitivity from 65% to 95% for identifying organism. Never start antibiotics before sampling! ### Step 2: Incision and Exposure Use **previous surgical approach** - most commonly posterior (Southern or Moore). **Posterior Approach**: - Position: Lateral decubitus, hip flexed 30° - Incision: Through previous scar, extending if needed - Expect dense scarring - careful dissection in tissue planes - Identify and protect sciatic nerve early - Tag short external rotators with sutures for later repair (if salvageable) **Considerations**: - Extended incision often needed for visualization - Anterior approach acceptable if previous approach - Trochanteric osteotomy if severe scarring/heterotopic ossification Previous surgery creates scar tissue obscuring normal anatomy. Identify sciatic nerve early and protect throughout. Consider intraoperative nerve monitoring in revision cases. ### Step 3: Synovectomy and Debridement **Radical synovectomy** - remove ALL infected/inflamed tissue: - Complete excision of pseudocapsule - Remove all granulation tissue - Debride necrotic tissue to healthy bleeding margins - Remove all foreign material (sutures, cement debris) - Debride bone surfaces to healthy bleeding bone **FRCS KEY**: "Radical debridement is the single most important factor for infection eradication." Inadequate debridement = treatment failure regardless of antibiotics. ### Step 4: Acetabular Component Removal **Cemented cup removal**: - Identify cement-bone interface - Use curved osteotomes to disrupt interface - Lever cup out progressively (protect posterior wall) - Remove ALL cement with curettes, osteotomes, high-speed burr **Uncemented cup removal**: - Curved osteotomes around rim to disrupt bone ingrowth - Avoid aggressive levering (acetabular fracture risk) - Specialized extraction devices for well-fixed components - May need acetabular rim osteotomy for extraction ### Step 5: Femoral Component Removal - Decision Point **Assessment**: Is stem loose or well-fixed? **If LOOSE**: - Extract with slap hammer and trunnion extractors - Remove all cement if cemented design - Relatively straightforward **If WELL-FIXED (cementless)**: - STOP - proceed to Extended Trochanteric Osteotomy (ETO) - Do NOT attempt brute force extraction (fracture risk 30%+) Attempting extraction of well-fixed cementless stem without ETO risks proximal femur fracture in 30%+ cases. Always plan for ETO when cementless revision anticipated. ### Step 6: Extended Trochanteric Osteotomy (ETO) - If Required **Indication**: Well-fixed cementless stem, distally fixed stem, cement mantle requiring removal. **Technique**: 1. Mark osteotomy length (usually 12-15cm, extending 2-3cm beyond stem tip) 2. Apply **prophylactic cerclage** at distal extent of planned osteotomy 3. Use oscillating saw for lateral and anterior cortical cuts 4. Create controlled crack with osteotomes (lateral to medial) 5. Open trochanteric fragment like a "book" - maintains muscle attachments 6. Now femoral component and cement are accessible 7. Remove component under direct vision **FRCS KEY**: ETO preserves abductor attachment, protects femur, allows complete cement removal, and heals reliably (95%+). This is the workhorse technique for revision femoral extraction. ### Step 7: Complete Cement Removal and Canal Preparation Remove **ALL cement** - any retained cement harbors bacteria in crevices: - High-speed burr for cement on cortical bone - Long curettes for canal cement - Ultrasonic tools if available - Serial reaming to fresh bleeding bone - Flexible reamers for curved canals **Debride medullary canal** to healthy tissue: - Sequential reaming until fresh bleeding bone - Remove all interface membrane - Brush canal walls ### Step 8: Copious Pulsatile Lavage **Minimum 9 litres** pulsatile lavage: - 3-6L during debridement - 3L final lavage before spacer insertion - Use pulsatile lavage system (not bulb syringe) Some surgeons use additive solutions (betadine, chlorhexidine, hydrogen peroxide) - evidence mixed, mainly saline. **FRCS KEY**: "Dilution is the solution to pollution." High-volume pulsatile lavage mechanically removes bacteria, debris, and planktonic organisms. Essential complement to debridement. ### Step 9: Antibiotic Cement Spacer Fabrication **Standard Formulation** (EXAM ESSENTIAL): - **2 × 40g cement** (80g total) - Palacos has best elution characteristics - **Vancomycin 4-6g** (Gram-positive, MRSA coverage) - **Tobramycin 3.6g** OR Gentamicin 2g (Gram-negative, biofilm penetration) - **Maximum 10% antibiotic by weight** to maintain mechanical properties **Mixing Technique**: 1. Mix antibiotic powders with cement powder FIRST (before liquid) 2. Ensure homogeneous distribution 3. Add liquid monomer 4. Mix until doughy consistency 5. Mould into spacer components **Spacer Types**: - **Articulating (preferred)**: Hand-moulded or modular systems (Prostalac, STAGE, Interspace) - **Static**: Reserved for severe bone loss, instability, medically unfit for mobilization Exceeding 10% antibiotic by weight weakens cement mechanically → spacer fracture. Balance antibiotic delivery with structural integrity. ### Step 10: Femoral Spacer Component Insertion **Hand-moulded spacer**: - Form cement around Steinmann pin or K-wire for reinforcement - Create stem shape that will fit canal - Insert in doughy phase, seat firmly - Maintain neutral alignment **Commercial spacer systems**: - Follow manufacturer technique - Select appropriate size based on canal dimensions - Ensure stable press-fit **Key points**: - Cement should interdigitate with cancellous bone for stability - Maintain leg length (avoid excessive shortening) - Slight anteversion (10-15°) ### Step 11: Acetabular Spacer Insertion **Options**: 1. **Articulating spacer head**: Cement hemispherical head placed on femoral component, articulates against native acetabulum (or augment cup) 2. **Cement into acetabulum**: Fill acetabular defect with antibiotic cement 3. **Commercial systems**: Pre-formed acetabular spacer components **Key considerations**: - Size head appropriately for stability (larger = more stable) - Ensure coverage by acetabulum - Accept some bone loss - reconstruction at stage 2 ### Step 12: Stability Assessment **Test stability in multiple positions**: - Hip flexion to 90° with internal rotation - Extension with external rotation - Assess for impingement, dislocation **If unstable**: - Larger head size - Adjust offset if possible - Consider constrained liner at stage 2 - Accept higher dislocation risk (10-20% inherent) - May need abduction brace post-operatively **FRCS KEY**: Spacer dislocation rate 10-20% is ACCEPTED. Prioritize infection eradication over perfect stability. Patients are on protected weight bearing anyway. ### Step 13: Wound Closure **Layered closure**: - Deep drains (2 minimum) - to antibiotic-loaded cavity - Capsule/short external rotator repair if possible - Fascia lata - strong absorbable suture - Subcutaneous - absorbable suture - Skin - staples or absorbable subcuticular **Consider**: - VAC dressing if wound compromise or planned return to OR - Tension-free closure essential (skin necrosis = exposed spacer = failure) ### Step 14: Documentation and Specimen Handling **Document in operative note**: - All tissue samples taken (locations, culture requests) - Components removed (manufacturer, size, condition) - Intraoperative findings (purulence, membrane, bone loss) - Spacer type and antibiotic content - Stability assessment **Specimen handling**: - Each tissue sample in SEPARATE container - Clearly labelled with site - Request prolonged culture (14 days) - Explanted components can be sent for sonication (biofilm disruption) ### Immediate Post-operative - **Weight bearing**: Toe-touch weight bearing with frame/crutches - **DVT prophylaxis**: LMWH or aspirin per protocol - **Drains**: Remove when <50mL/24hrs (usually day 2-3) - **IV antibiotics**: Start post-operatively based on cultures (empiric initially) ### Antibiotic Protocol - **Duration**: Minimum 6 weeks IV antibiotics - **PICC line**: Insert before discharge - **Outpatient parenteral antibiotic therapy (OPAT)**: Home or infusion centre - **Tailored regimen**: Adjust based on culture sensitivities when available - **ID involvement**: Essential for complex organisms, optimize regimen ### Monitoring During Spacer Period - **Weekly bloods**: CRP, ESR (expect initial rise then gradual normalization) - **Clinical assessment**: Wound healing, pain, systemic symptoms - **Watch for**: Spacer dislocation (sudden pain, shortening), fracture, persistent drainage ### Criteria for Stage 2 (EXAM ESSENTIAL) 1. **Minimum 6 weeks IV antibiotics** completed 2. **2-6 week antibiotic holiday** (to allow re-aspiration) 3. **Normalized inflammatory markers**: CRP <10, ESR <30 for 2+ consecutive weeks 4. **Negative aspiration** during antibiotic holiday 5. **Healed wound** with no drainage 6. **No clinical signs of infection** **FRCS KEY**: Do NOT rush to stage 2. Persistent infection = stage 2 failure. Wait until ALL criteria met. Typical interval is 8-12 weeks but may be longer. ## References 1. Parvizi J, et al. New definition for periprosthetic joint infection: from the Workgroup of the Musculoskeletal Infection Society. Clin Orthop Relat Res. 2011;469(11):2992-2994. 2. Kurtz SM, et al. Economic burden of periprosthetic joint infection in the United States. J Arthroplasty. 2012;27(8 Suppl):61-65. 3. Hsieh PH, et al. Two-stage revision hip arthroplasty for infection: comparison between interim cement spacer and antibiotic-loaded cement prosthesis. J Bone Joint Surg Am. 2004;86(9):1989-1997. 4. Younger AS, et al. The outcome of two-stage arthroplasty using a custom-made interval spacer to treat infected hip arthroplasty. J Arthroplasty. 1997;12(6):615-623. 5. Masri BA, et al. Cementless two-stage exchange arthroplasty for infection after total hip arthroplasty. J Arthroplasty. 2007;22(1):72-78. 6. Fink B, et al. Two-stage cementless revision of infected hip endoprostheses. Clin Orthop Relat Res. 2009;467(7):1848-1858. 7. Penner MJ, et al. The extended trochanteric osteotomy in femoral component revision. Orthop Clin North Am. 1999;30(2):219-226. 8. Springer BD, et al. Systemic antibiotic regimens for periprosthetic joint infection in adults: a review. Curr Rev Musculoskelet Med. 2018;11(1):103-110. 9. Osmon DR, et al. Diagnosis and management of prosthetic joint infection: clinical practice guidelines by IDSA. Clin Infect Dis. 2013;56(1):e1-e25. 10. Tan TL, et al. Culture-negative periprosthetic joint infection: an update on what to expect. J Bone Joint Surg Am. 2018;100(12):1124-1133.

Two-Stage Revision THA - Stage 1: Antibiotic Cement Spacer Insertion

Two-Stage Revision THA - Stage 1: Antibiotic Cement Spacer Insertion