import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' **5-10mm posterior to posterior tibial cortex** - At maximum risk during posterior retraction, tibial component extraction, and cement removal. Risk increases with fixed flexion deformity and posterior osteophytes. **EXAM KEY: Maintain knee in flexion, careful posterior retractor placement, never place instruments posteriorly blindly** **Wraps around fibular neck 2-4cm below joint line** - At risk during lateral release, lateral retraction, and valgus correction. Injury causes foot drop. **EXAM KEY: Limit lateral retraction, identify nerve if extensive lateral release needed, avoid valgus overcorrection** **Inserts on tibial tubercle** - At risk during exposure, component removal, and eversion. Scarred in revision setting. Avulsion catastrophic. **EXAM KEY: Consider TTO if patellar eversion difficult, protect during entire procedure, never force eversion** **Thin cortices in revision, stress risers from previous surgery** - Perforation risk during cement removal, reaming, and stem insertion. Posterior cortex most vulnerable. **EXAM KEY: Use fluoroscopy, ball-tip guidewire, avoid eccentric reaming** **MCL inserts 5-6cm below joint line on proximal tibia** - At risk during medial release, component extraction, and stem insertion. Incompetence leads to instability. **EXAM KEY: Protect during extraction, assess at trial, may need higher constraint if damaged** ## Indications for Tibial Revision ### Primary Indications - **Aseptic loosening** - Progressive radiolucent lines, subsidence, pain - **Polyethylene wear** - Isolated liner exchange if tray stable and well-positioned - **Infection** - Stage 2 of two-stage revision for PJI - **Instability** - Tibial component malposition contributing to instability - **Osteolysis** - Progressive tibial bone loss ### Secondary Indications - **Malalignment** - Varus/valgus tibial component malposition - **Periprosthetic fracture** - Fracture through tibial tray - **Component failure** - Baseplate fracture, locking mechanism failure - **Isolated tibial issue** - With well-fixed, well-positioned femoral component **AOANJRR Data**: Most common reasons for TKA revision: loosening (30%), infection (25%), instability (15%), pain (10%). Tibial component loosening more common than femoral. Re-revision rate 15-20% at 10 years. ### Contraindications - **Active infection** - Must complete two-stage protocol - **Severe vascular disease** - Risk of limb loss - **Non-functioning extensor mechanism** - Consider arthrodesis - **Inadequate soft tissue coverage** - May need flap ## AORI Tibial Bone Loss Classification Anderson Orthopaedic Research Institute classification: ### Type 1 - Minor Bone Loss - **Description**: Intact metaphyseal bone, minor cancellous defects - **Cortical rim**: Intact circumferentially - **Treatment**: Cement fill or small augments - **Fixation**: Can achieve metaphyseal fixation with standard tibial baseplate ### Type 2A - Unilateral Condylar Defect - **Description**: One tibial plateau damaged, other intact - **Pattern**: Usually medial from varus malalignment - **Treatment**: Metal augments (blocks) on affected side - **Fixation**: Stem for stability, augment to fill defect ### Type 2B - Bilateral Condylar Defects - **Description**: Both tibial plateaux compromised - **Cortical rim**: Compromised on both sides - **Treatment**: Sleeves or metaphyseal cones - **Fixation**: Metaphyseal engagement with sleeve/cone + stem ### Type 3 - Deficient Metaphysis - **Description**: Massive bone loss, no metaphyseal support - **Pattern**: Often from multiple previous revisions or infection - **Treatment**: Proximal tibial replacement (megaprosthesis) or structural allograft - **Fixation**: Diaphyseal only, or allograft-prosthesis composite **Key Distinction**: Type 2A vs 2B determines unilateral augments vs circumferential sleeves/cones. Type 3 is salvage situation requiring megaprosthesis or allograft. ## Bone Loss Management Options ### Cement (Type 1, small contained defects) - **Indication**: Defects less than 5mm depth, contained - **Technique**: Pack cement into defect, press baseplate - **Pros**: Simple, no additional implants - **Cons**: No structural support, cement shrinkage ### Metal Augments/Blocks (Type 2A) - **Indication**: Unilateral defects 5-25mm - **Options**: Half blocks, full blocks, wedges - **Technique**: Cement between augment and bone, baseplate on augment - **Pros**: Versatile, available in multiple sizes - **Cons**: Multiple interfaces, cement reliance ### Tibial Sleeves (Type 2B) - **Examples**: DePuy Attune S+, Smith & Nephew Legion - **Indication**: Bilateral metaphyseal loss, compromised cortical rim - **Mechanism**: Press-fit metaphyseal engagement with porous ingrowth - **Pros**: Biologic fixation, load sharing, restores joint line - **Cons**: Bone removal during preparation, difficult removal ### Metaphyseal Cones (Type 2B/3) - **Examples**: Zimmer TM Cone, Stryker Tritanium Cone - **Indication**: Severe metaphyseal bone loss, contained defects - **Mechanism**: Impaction fit with cancellous bone ingrowth - **Pros**: Fills large cavitary defects, biologic fixation - **Cons**: Requires contained defect, technique dependent ### Stems - **Length**: 75-200mm options - **Fixation**: Press-fit (most common) or cemented - **Offset**: Available to adjust alignment without affecting canal position - **Rule**: Must bypass defects by 2 cortical diameters (typically 4-6cm) ### Proximal Tibial Replacement (Type 3) - **Indication**: Massive bone loss, failed multiple revisions - **Mechanism**: Replaces entire proximal tibia - **Pros**: Salvage option, predictable reconstruction - **Cons**: Complex soft tissue management, extensor mechanism issues ## Essential Equipment ### Component Removal Instruments - **Osteotomes** - Thin, flexible for cement-bone interface - **Gigli saw** - For cutting cement mantle - **Oscillating saw** - For TTO if needed - **Universal extraction devices** - Slap hammers, extraction hooks ### Revision Tibial System - **Baseplate sizes** - Multiple sizes and offsets - **Stems** - Various lengths (75-200mm), diameters, offset options - **Augments** - Blocks (5mm increments), wedges - **Sleeves/cones** - Multiple sizes for metaphyseal engagement ### Constraint Options - **Posterior-stabilized (PS)** - Standard revision - **Varus-valgus constrained (VVC)** - Moderate instability - **Rotating hinge** - Severe instability, collateral deficiency ### Bone Graft - **Morsellized allograft** - Contained defects - **Structural allograft** - Type 3 massive loss - **Bone graft substitutes** - Calcium phosphate, demineralized bone matrix ### Additional Equipment - **Fluoroscopy** - For stem positioning, cement removal - **Knee braces** - For post-operative protection if instability concerns ### Essential Imaging 1. **Weight-bearing AP and lateral** - Component position, loosening signs 2. **Long-leg alignment films** - Mechanical axis, joint line position 3. **Skyline patella view** - Patellar tracking, component position 4. **CT scan** - Quantify bone loss, assess for osteolysis ### Templating - Classify bone loss using AORI system - Plan stem length - bypass defects by 2 cortical diameters - Assess joint line position - restore to 10-15mm below inferior patella pole - Plan augment/sleeve/cone sizes - Determine constraint level needed ### Infection Work-up - **ESR, CRP** - Elevated in 80-90% of PJI - **Knee aspiration** - Synovial WCC greater than 3000, PMN greater than 80% - **Alpha-defensin** - High sensitivity and specificity - **Rule out infection before any aseptic revision** ### Special Considerations - **Previous incisions** - Use most lateral if multiple parallel - **Soft tissue quality** - Consider plastic surgery input if poor - **Extensor mechanism** - Plan TTO if eversion expected to be difficult **Joint Line Rule**: The joint line should be 10-15mm below the inferior pole of the patella, or approximately 25mm below the medial epicondyle. Elevation leads to mid-flexion instability, lowering leads to extensor mechanism problems. ### Incision Planning - **Use most lateral previous incision** - Better blood supply from medial - **Minimum 7cm between parallel incisions** - Avoid skin bridge necrosis - **Consider plastic surgery consult** - If soft tissue compromised ### Standard Approach 1. **Midline skin incision** - Through or lateral to previous scar 2. **Medial parapatellar arthrotomy** - Most common, familiar anatomy 3. **Release adhesions** - Medial and lateral gutters, suprapatellar pouch 4. **Patellar eversion or lateral subluxation** - Assess difficulty before forcing ### Extensile Options **Quadriceps Snip:** - 45-degree proximal extension into quadriceps tendon - Easy closure, minimal morbidity - First-line extensile approach **Tibial Tubercle Osteotomy (TTO):** - Indications: Unable to evert patella, prior extensor mechanism surgery, multiply revised knee - Osteotomy length: 8-10cm - Width: 1-2cm - Hinge on lateral soft tissue - Closure: Cerclage wires or screws **Rectus Snip:** - Inverted V in quadriceps tendon - Good exposure but more difficult closure - Consider if TTO contraindicated - Never force patellar eversion - patellar tendon avulsion catastrophic - Use extensile exposure early rather than struggling - TTO healing rate greater than 95% with proper technique - Protect patellar tendon throughout entire procedure ### Polyethylene Insert Removal 1. **Identify locking mechanism** - Peripheral or anterior 2. **Use appropriate removal tool** - Match to implant system 3. **Avoid damaging tibial tray** - If liner exchange planned ### Tibial Baseplate Removal **Loose Component:** 1. Remove polyethylene insert 2. Thin osteotomes around baseplate periphery 3. Extract baseplate - may lift off easily **Well-Fixed Component:** 1. Remove polyethylene insert first 2. Identify cement-implant vs cement-bone interface 3. Thin osteotomes at chosen interface 4. Gigli saw helpful for cutting cement mantle 5. Extract baseplate - use extraction device if needed ### Stem Removal 1. **Cemented stem** - Osteotomes at cement-bone interface, cement removal tools 2. **Press-fit stem** - Extraction devices, may need distal window if well-fixed 3. **Protect posterior structures** - Never insert instruments blindly posteriorly ### Cement Removal - **Hand curettes** - For accessible cement - **Ultrasonic cement removal** - Preserves bone stock - **High-speed burr** - For difficult areas - **Fluoroscopy essential** - Ensure complete removal, prevent perforation **Cement Removal Pearl**: Removing cement from the posterior tibia is high risk for popliteal vessel injury. Use fluoroscopy, work under direct vision, and never insert long instruments blindly posteriorly. ### Intraoperative Assessment 1. **Remove all components and cement** 2. **Assess cortical rim** - Intact vs compromised 3. **Classify using AORI** - Type 1, 2A, 2B, or 3 4. **Assess ligamentous stability** - MCL, LCL, PCL (if not PS) ### Type 1 Management - **Bone stock adequate** - Cortical rim intact - **Technique**: Minimal resection to healthy bone - **Augmentation**: Cement fill for defects less than 5mm - **Stem**: May not need stem if stable - **Constraint**: Usually PS sufficient ### Type 2A Management - **Unilateral condylar loss** - Usually medial from varus wear - **Technique**: Resect to healthy bone on intact side - **Augmentation**: Metal block(s) on deficient side - **Stem**: Required for stability (75-100mm typical) - **Constraint**: PS or VVC depending on soft tissue ### Type 2B Management - **Bilateral metaphyseal loss** - Compromised cortical rim - **Technique**: Prepare metaphysis for sleeve or cone - **Augmentation**: Tibial sleeve or metaphyseal cone - **Stem**: Required, diaphyseal engagement - **Constraint**: VVC often needed due to associated soft tissue laxity ### Type 3 Management - **Massive bone loss** - No metaphyseal support - **Options**: - Proximal tibial replacement (megaprosthesis) - Allograft-prosthesis composite - Impaction grafting (rarely used in tibia) - **Stem**: Long diaphyseal engagement essential - **Constraint**: Rotating hinge usually required **Sleeve vs Cone**: Sleeves provide circumferential metaphyseal fixation and come in fixed sizes requiring bone preparation. Cones are impacted into contained defects and don't require as much bone removal. Sleeves restore joint line more predictably. ### Joint Line Restoration - **Reference**: 10-15mm below inferior patella, 25mm below medial epicondyle - **Significance**: Elevated joint line causes mid-flexion instability - **Technique**: Use augments/sleeves to restore appropriate level ### Trial Reduction 1. **Insert trial tibial tray with stem** 2. **Check rotation** - Match to femoral component, tibial tubercle 3. **Check coverage** - Maximize tibial coverage without overhang 4. **Check stability** - Full ROM, varus/valgus stress, drawer tests 5. **Check tracking** - Patellar tracking with thickest poly anticipated ### Stem Selection - **Length**: Bypass all defects by 2 cortical diameters - **Diameter**: Largest that fits diaphysis comfortably - **Offset**: Use if needed to improve alignment without affecting canal - **Fixation**: Press-fit preferred (most cases) or cemented (poor bone) ### Final Implantation **Cementless/Hybrid (Most Common):** 1. Sleeve/cone impacted to final position 2. Press-fit stem inserted 3. Baseplate seated on sleeve 4. Cement under tray for surface fixation **Cemented:** 1. Cement in metaphysis and around stem 2. Insert stem and tray as unit 3. Pressurize cement 4. Remove excess cement meticulously ### Constraint Selection - **PS (Posterior-Stabilized)**: Intact collaterals, minimal bone loss - **VVC (Varus-Valgus Constrained)**: Moderate collateral laxity, Type 2 bone loss - **Rotating Hinge**: Severe instability, collateral deficiency, Type 3 bone loss ### When TTO Performed **Closure Technique:** 1. **Position** - Reduce TTO fragment anatomically 2. **Compression** - Achieve fragment apposition 3. **Fixation options**: - Cerclage wires (most common) - 2-3 wires - Screws (2-3 cortical screws proximal to distal) - Combination wire and screw **Post-operative Protocol:** - **Weight-bearing**: WBAT with extension brace - **ROM**: Limit flexion to 90° for 6 weeks - **Healing time**: 8-12 weeks typically - **Union rate**: greater than 95% with proper technique - Fragment must be long enough (8-10cm) to allow secure fixation - Lateral soft tissue hinge must remain intact - Avoid proximal migration during closure - Non-union rate increases with poor fixation, smoking, diabetes ### Weight-Bearing - **Standard revision**: WBAT with walker/crutches - **With TTO**: WBAT in extension brace, limit flexion to 90° for 6 weeks - **Type 3/structural graft**: Protected weight-bearing per surgeon discretion ### Bracing - **TTO**: Extension brace for 6 weeks, hinged brace 6-12 weeks - **VVC/Rotating hinge**: Consider brace for soft tissue healing - **Instability concerns**: Hinged brace until stable ### Thromboprophylaxis - **LMWH or DOAC** - 35 days per Australian guidelines - **Mechanical prophylaxis** - IPC devices while inpatient - **Early mobilization** - Day 1 post-operatively ### Rehabilitation - **Phase 1 (0-6 weeks)**: ROM exercises, quadriceps strengthening, gait training - **Phase 2 (6-12 weeks)**: Progressive strengthening, stair training, balance - **Phase 3 (12+ weeks)**: Return to activities, functional training ### Follow-up Imaging - **6 weeks**: AP and lateral - assess component position, TTO healing - **3 months**: Weight-bearing films - **Annual**: Long-term surveillance **Revision TKA Rehab**: Recovery slower than primary TKA. Set appropriate expectations - 12 months to maximal improvement. Functional outcomes inferior to primary TKA - most achieve 100-110° flexion. 1. Engh GA, Ammeen DJ. Bone loss with revision total knee arthroplasty: defect classification and alternatives for reconstruction. *Instr Course Lect*. 1999;48:167-175. 2. Morgan-Jones R, Oussedik SI, Graichen H, Haddad FS. Zonal fixation in revision total knee arthroplasty. *Bone Joint J*. 2015;97-B(2):147-149. 3. Whiteside LA. Cementless revision total knee arthroplasty. *Clin Orthop Relat Res*. 2006;446:140-148. 4. Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). Annual Report 2023. Knee revision outcomes and survival data. 5. Dalury DF, Adams MJ. Tibial tubercle osteotomy during revision total knee arthroplasty. *J Arthroplasty*. 2013;28(1):33-37. 6. Haidukewych GJ, Hanssen A, Jones RD. Metaphyseal fixation in revision total knee arthroplasty: indications and techniques. *J Am Acad Orthop Surg*. 2011;19(6):311-318. 7. Potter GD III, Abdel MP, Lewallen DG, Hanssen AD. Midterm results of porous tantalum femoral cones in revision total knee arthroplasty. *J Bone Joint Surg Am*. 2016;98(15):1286-1291. 8. Graichen H, Scior W, Strauch M. Direct, cementless, metaphyseal fixation in knee revision arthroplasty with sleeves - short-term results. *J Arthroplasty*. 2015;30(12):2256-2259. 9. Fehring TK, Odum S, Oleksy C, et al. Stem fixation in revision total knee arthroplasty: a comparative analysis. *Clin Orthop Relat Res*. 2003;416:217-224. 10. Lee JK, Lee S, Kim D, et al. Revision total knee arthroplasty with varus-valgus constrained prosthesis versus rotating-hinge prosthesis. *Knee Surg Sports Traumatol Arthrosc*. 2020;28(2):518-524.

Revision TKA - Tibial Component Revision

Revision TKA - Tibial Component Revision