import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' **LOCATION**: 10-15mm posterior to posterior tibial cortex, courses through popliteal fossa at joint line level. **HIGHEST RISK DURING**: Posterior cement removal with osteotomes, tibial component extraction in revision, posterior capsular releases, tibial stem insertion. **PROTECTION**: Stay anterior to posterior cortex, place broad posterior retractors under direct vision, use pulsatile lavage rather than sharp instruments for posterior cement, avoid aggressive posterior work. **LOCATION**: Accompanies popliteal artery posterior to tibial cortex, thinner wall than artery. **HIGHEST RISK DURING**: Same situations as artery - possibly higher injury rate due to thinner wall, more easily torn. **PROTECTION**: Identical protection strategies as artery, maintain anterior position, gentle technique, broad retractors. **LOCATION**: Winds around fibular neck 2-3cm distal to fibular head, courses superficial and lateral. **HIGHEST RISK DURING**: Lateral post pressure in long cases, valgus stress during varus deformity correction, lateral releases, tourniquet compression. **PROTECTION**: Pad lateral post carefully, correct deformity gradually, limit tourniquet time, consider tourniquet-free in high-risk cases. Injury rate 1-2% in revision vs 0.5% primary - causes foot drop. **LOCATION**: Posterior to popliteal vessels in popliteal fossa, courses medially. **HIGHEST RISK DURING**: Aggressive posterior work, deep posterior releases, posterior cement removal. **PROTECTION**: Stay anterior to posterior cortex, limit posterior dissection, protect with retractors during any posterior work. **LOCATION**: Patellar tendon insertion on tibial tubercle, quadriceps tendon, patella blood supply from lateral superior genicular and medial inferior genicular arteries. **HIGHEST RISK DURING**: Forceful patellar eversion, excessive lateral release, revision component removal. **PROTECTION**: Use enhanced exposure techniques early (quadriceps snip, V-Y, TTO) rather than forcing eversion, preserve lateral superior genicular if possible, gentle tissue handling. ## Primary Indications **Severe Instability** - Collateral ligament deficiency (MCL/LCL insufficiency) - Failed soft tissue balancing in primary or revision TKR - Massive bone loss preventing stable ligament insertion - Neuromuscular disorders (polio, cerebral palsy, post-stroke) - Neuropathic joint (relative indication, high failure risk) **Revision Scenarios** - Failed primary TKR with instability pattern - Massive bone loss (AORI Type 3) requiring structural support - Extensor mechanism dysfunction requiring constrained stability - Multiple revision failures with progressive instability - Periprosthetic fracture with associated bone loss **Bone Loss Requiring Structural Support** - AORI Type 3 defects with compromised metaphyseal segment - Combined defects exceeding capacity of standard implants - Inability to restore joint line with standard components ## Preoperative Planning Essentials **Imaging Protocol** - Standing AP and lateral knee radiographs - Long-leg alignment films (hip-knee-ankle mechanical axis) - Oblique views to assess bone stock and defects - CT scan if severe bone loss - quantify defect size, location, depth - Consider metal artifact reduction sequences if previous implants **Constraint Level Decision Tree** - Standard PS: Stable with intact collaterals, no constraint needed - VVC/CCK (semi-constrained): Moderate laxity 5-10mm, functioning extensor - Rotating hinge: Severe laxity over 10mm OR extensor dysfunction - Non-rotating hinge: Massive instability, tumor reconstruction (rare) **Bone Loss Assessment (AORI Classification)** - Type 1: Minimal loss, intact metaphysis - no augmentation needed - Type 2A: Contained defects less than 5mm - cement or small augments - Type 2B: Uncontained defects less than 5mm - metal augments required - Type 3: Deficient metaphyseal segment - metaphyseal cones, sleeves, or structural allograft **Stem Planning** - Length: 100-150mm standard, bypass defects by 2 cortical diameters (70-100mm) - Diameter: Maximum that fits without perforation, 80% canal fill for press-fit - Fixation: Cemented preferred in osteoporotic/compromised bone, press-fit if incomplete cement removal - Offset stems available if metaphyseal-diaphyseal axis mismatch **Extensor Mechanism Assessment** - Patellar tendon integrity and quality - Quadriceps tendon integrity - Patella bone stock and previous component status - Plan reconstruction if disruption (allograft, synthetic mesh, gastrocnemius flap) ## Surgical Anatomy Relevant to Constrained TKR **Popliteal Vessels - Critical Posterior Structures** - Popliteal artery: 10-15mm posterior to posterior tibial cortex - Popliteal vein: Accompanies artery, thinner wall, higher injury risk - Course through popliteal fossa at joint line level - Protected by staying anterior, using broad retractors, gentle technique **Common Peroneal Nerve** - Winds around fibular neck 2-3cm distal to fibular head - Superficial and vulnerable to compression - Injury causes foot drop (dorsiflexion weakness, numbness dorsum foot) - Higher injury rate in revision (1-2% vs 0.5% primary) - Risk factors: Valgus stress, lateral post pressure, prolonged tourniquet **Extensor Mechanism Blood Supply** - Patella: Fed by lateral superior genicular, medial inferior genicular arteries - Compromised by excessive lateral release or multiple previous surgeries - Patellar tendon: Vulnerable to avulsion during forceful eversion - Quadriceps tendon: Rectus femoris blood supply critical **Collateral Ligaments** - MCL: Superficial fibers femur to tibia, deep fibers to meniscus - Often attenuated or absent in cases requiring constrained implants - LCL: Femur to fibular head, often deficient in valgus deformity - Assessment critical for constraint level selection ## Approach Selection **Standard Medial Parapatellar** - First choice if adequate exposure achievable - Medial border of quadriceps tendon to medial patella to tibial tubercle - Evert patella laterally - do NOT force if resistance **Enhanced Exposure Techniques (Order of Invasiveness)** 1. **Early Lateral Release** - Facilitates patellar eversion without forceful tension - Preserve lateral superior genicular artery if possible - First-line enhancement before more invasive techniques 2. **Quadriceps Snip (Garvin)** - 45° oblique extension into quadriceps tendon LATERALLY - Direction away from rectus femoris to preserve blood supply - Extends exposure approximately 2cm - Repair with #5 non-absorbable suture (Ethibond, FiberWire) - Protected weight bearing 6 weeks with brace 3. **V-Y Quadricepsplasty (Coonse-Adams)** - Inverted V incision in quadriceps tendon proximally - Advanced distally and closed as Y configuration - Preserves rectus femoris blood supply - Superior to snip for severely stiff knee - Lengthens extensor mechanism, reduces tension - Repair with #5 non-absorbable suture 4. **Tibial Tubercle Osteotomy (TTO)** - Most invasive, reserved for severe stiffness or extensor issues - Lateral-to-medial osteotomy, 5-7cm long, 1cm thick - Maintain lateral soft tissue hinge for blood supply - Allows tubercle medialization for patellar tracking - Fixation with 2-3 cables or bicortical screws - Touch-toe weight bearing 6 weeks until union ## Positioning - Supine with operative leg free to flex - Foot of table dropped for flexion access - Lateral post at hip level (pad to protect common peroneal nerve) - Tourniquet high on thigh (300mmHg or LOP+100mmHg) - Consider lower pressure (250mmHg) or tourniquet-free in revision - Prep and drape to allow full hip-to-ankle access for alignment ## Comprehensive Operative Technique ### Step 1: Exposure and Component Removal (If Revision) **Incision Strategy** - Utilize previous incisions if present - choose most LATERAL to preserve medial blood supply - May need extended incision proximally/distally for exposure - Full-thickness skin flaps to capsule (minimum 5-7mm) **Arthrotomy** - Standard medial parapatellar through capsule - Assess extensor mechanism carefully before proceeding - Use enhanced exposure early rather than forcing eversion **Component Removal in Revision (Systematic Approach)** 1. Remove polyethylene insert first with osteotomes 2. Femoral component: Osteotomes at cement-bone interface, work circumferentially, Gigli saw if well-fixed 3. Tibial component: Osteotomes at interface, remove cement restrictor 4. Patellar component: Retain if stable/well-positioned, remove if loose 5. ALL cement removal: High-speed burr, osteotomes, pulsatile lavage (critical for stem insertion) 6. Remove synovial/inflammatory membrane completely 7. Multiple tissue samples for culture and histology (even if not infected) **Technical Tip**: Component removal in revision requires patience and meticulous technique. Preserve bone stock at all costs - aggressive removal risks periprosthetic fracture. Remove ALL cement especially from medullary canal for stem insertion. Stay anterior during posterior cement removal to protect popliteal vessels. Send multiple tissue samples for culture even if not clinically infected. - Popliteal vessel injury during posterior cement removal - STAY ANTERIOR - Periprosthetic fracture from aggressive component removal - Extensor mechanism disruption from forceful eversion - use enhanced exposure - Incomplete cement removal compromises stem fixation ### Step 2: Bone Loss Assessment and Augmentation Planning **Systematic AORI Classification** - Assess both femur and tibia separately after component removal - Type 1: Intact metaphysis, cement fill only - Type 2A: Contained defects less than 5mm, small augments or cement - Type 2B: Uncontained defects less than 5mm, metal augments needed - Type 3: Deficient metaphyseal segment, requires cones/sleeves/structural graft **Augmentation Strategy by Defect Type** *Type 2B/3 Defects - Metal Modular Augments* - Wedges or blocks, cemented to host bone and component - Advantages: Immediate stability, no disease transmission, durable - Sizes: 5mm, 10mm, 15mm increments typically - Must have minimum 50% surface contact with host bone *Type 3 Massive Defects - Metaphyseal Cones/Sleeves* - Porous tantalum or titanium, press-fit metaphyseal fixation - Advantages: Excellent initial stability, biologic ingrowth, preserves bone stock - Superior to structural allograft in most cases - Stem typically cemented into cone *Structural Allograft (Reserved for Specific Cases)* - Femoral head or distal femur/proximal tibia allograft - For massive Type 3 defects when cones insufficient - Disadvantages: Resorption, collapse (10-20%), non-union, disease transmission **Technical Tip**: My preference for Type 2B/3 defects: Metal modular augments for contained or moderate defects - immediate stability, reliable fixation. Metaphyseal cones for massive uncontained Type 3 defects - superior to allograft with immediate stability and biologic ingrowth potential. Structural allograft reserved for massive defects beyond cone capacity, but higher complication rates. ### Step 3: Bone Cuts and Preparation **Tibial Cut** - Extramedullary guide preferred - Perpendicular to tibial axis (0° coronal) - Posterior slope: 3° (LESS than primary - constrained designs more stable) - Resection level: Remove diseased bone to healthy metaphysis - Use augments rather than excessive resection to restore joint line **Distal Femoral Cut** - Extramedullary guide preferred if canal compromised - 5-7° valgus cut angle - Resect to healthy metaphyseal bone - May require asymmetric resection if one condyle more damaged **Box Cut for Constrained Post** - Larger than standard PS: Typically +2-4mm deeper and wider - Use box cutting guide specific to implant system - Protect posterior cortex (rare breach, usually not clinically significant) - Adequate clearance for constrained post through ROM **Femoral Rotation** - Three reference methods: Transepicondylar axis (most reliable), Whiteside's line, posterior condylar axis +3° external rotation - Often landmarks destroyed in revision - rely on epicondylar axis - Consider computer navigation if available and landmarks destroyed - Malrotation causes instability and accelerated wear - Excessive bone resection elevates joint line - causes patella baja - Inadequate resection fails to reach healthy bone - poor seating - Box cut posterior cortex breach - rare, stabilize if fracture - Femoral malrotation - especially challenging with destroyed landmarks ### Step 4: Stem Preparation **Stem Length Selection** - Standard: 100-150mm for load sharing and fixation - Must bypass defect by minimum 2 cortical diameters (70-100mm) - In periprosthetic fracture: Bypass fracture by 2 cortical diameters **Stem Diameter and Preparation** - Sequential reaming or broaching - Maximum diameter that fits without cortical perforation - Aim for 80% canal fill for press-fit stems - Check alignment with guides - stem aligns with mechanical axis - Trial stems confirm fit, length, alignment, no perforation **Fixation Strategy** - Cemented: Preferred, more reliable in osteoporotic/compromised bone - Press-fit metaphyseal engaging: If cement removal incomplete - Offset stems: Available for metaphyseal-diaphyseal mismatch **Technical Tip**: I prefer cemented stems for reliable fixation in compromised bone. Sequential reaming to maximum diameter that fits safely - typically 80% canal fill. Cement restrictor at stem tip, then retrograde cement injection with cement gun for complete fill and pressurization. Trial stems critical to confirm proper length (bypassing defect by 2 cortical diameters), alignment, and no perforation. ### Step 5: Trial Assessment and Constraint Selection **Systematic Trial Evaluation** *Stability Testing (CRITICAL for Constraint Selection)* - Test at 0° extension: Varus/valgus stress, measure opening - Test at 90° flexion: Varus/valgus stress, assess AP stability - Opens less than 5mm with moderate force: Standard PS adequate - Opens 5-10mm: VVC/CCK semi-constrained required - Opens greater than 10mm: Rotating hinge required *Alignment Verification* - Mechanical axis rod from hip to ankle - Should pass through knee center - Coronal alignment: 0° ± 3° (neutral mechanical axis) *Range of Motion* - Target: 0° extension to 110° flexion minimum - Check no impingement in deep flexion or full extension - Post-cam engagement smooth without impingement *Joint Line Restoration* - Within 8mm of anatomic (1cm below inferior pole patella) - Elevation causes patella baja, extensor dysfunction - Use augments to restore rather than accepting elevation *Patellar Tracking* - Assess tracking through ROM - Perfect tracking unrealistic in revision - Address if severely abnormal (lateral release, tubercle medialization if TTO) **Technical Tip**: Trial assessment focuses on STABILITY evaluation for correct constraint level. I systematically test varus/valgus at 0° and 90°, measure opening with moderate stress. 5-10mm opening indicates VVC/CCK, over 10mm indicates rotating hinge. Under-constraining leads to persistent instability and failure. Over-constraining increases interface stress, aseptic loosening, periprosthetic fracture. ### Step 6: Cementation and Final Implantation **Preparation** - Copious pulsatile lavage (6L+ in revision) - Dry with suction and sponges - Hydrogen peroxide for hemostasis (optional) - Mix antibiotic cement: 3rd generation with gentamicin OR high-dose gentamicin/vancomycin in revision **Tibial Component Cementation** 1. Cement augments to tibial bone first if used - pressurize into host bone 2. Cement restrictor/plug at stem tip 3. Brush and dry medullary canal 4. Retrograde cement injection with cement gun to stem tip 5. Pressurize cement along entire stem length 6. Apply cement to tibial baseplate undersurface and augment interface 7. Insert stem into canal first, then seat baseplate with compression 8. Hold under axial compression during cure (10-12 minutes) 9. Remove ALL excess cement - especially posteriorly (popliteal vessel risk) **Femoral Component Cementation** 1. Cement augments to femoral bone first if used 2. Cement restrictor at stem tip 3. Retrograde cement injection to stem tip, pressurize 4. Apply cement to component, augment interfaces, box cut 5. Insert stem, seat component in CORRECT ROTATION (verify landmarks) 6. Hold under compression during cure 7. Remove excess cement from box cut area and posterior condyles **Constrained Polyethylene Insert** - Select thickness based on gap balancing during trials - VVC/CCK: Constrained poly with tall post and anterior lip - Rotating hinge: Rotating bearing on tibial plateau - Verify secure locking mechanism - test by attempting dislodgement - Check post clearance in box through full ROM - Final stability testing confirms appropriate constraint - Incomplete stem cementation causes loosening, subsidence - Posterior cement extrusion risks popliteal vessel injury - Component malalignment during cementation - Cement in box area causes post impingement - Polyethylene dislodgment catastrophic - verify locking ### Step 7: Patellar Management **Primary Constrained TKR** - Standard resurfacing principles apply - Resurface if: Inflammatory arthritis, significant wear, maltracking - Leave minimum 12-15mm residual bone stock **Revision Scenarios** - Previous component stable/well-positioned: RETAIN - Previous component loose: Remove and resurface if adequate bone stock (greater than 10-12mm) - Inadequate bone stock after removal: Options include no resurfacing (gull-wing), trabecular metal/tantalum augment reconstruction, patellar allograft **Tracking Assessment** - Often abnormal due to scar, previous surgeries, altered kinematics - Address if severely abnormal (selective lateral release, tubercle medialization if TTO performed) - Accept mild abnormality - common with constrained implants ### Step 8: Final Assessment and Closure **Comprehensive Final Check** - Stability: Varus/valgus stress at 0° and 90° - should be stable - Alignment: Mechanical axis through knee center - ROM: 0° to 110° minimum, no impingement - Tracking: Acceptable (perfect unrealistic in revision) - Joint line: Within 8mm of anatomic - Post-cam: Smooth engagement, no impingement **Manipulation if Needed** - Check for mechanical blocks first (cement, osteophytes) - Careful manipulation if required - HIGH RISK in revision - Risk: Periprosthetic fracture (especially with stems), extensor rupture **Closure Technique** *Enhanced Exposure Repair* - Quadriceps snip: #5 non-absorbable suture (Ethibond, FiberWire) - V-Y quadricepsplasty: Advance quadriceps distally, #5 non-absorbable - TTO: Reduce anatomically or medialized, 2-3 cables or bicortical screws *Extensor Mechanism Reconstruction (If Needed)* - Primary repair with synthetic mesh augmentation (Marlex, GoreTex) - Achilles tendon allograft reconstruction - Medial gastrocnemius flap for coverage and augmentation - Protect with knee brace/immobilizer postoperatively *Standard Closure* - Capsule/arthrotomy: Interrupted #1 Vicryl, secure closure critical - Subcutaneous: Layer closure - Drain: Optional, consider if significant dead space (higher infection risk vs hematoma) - Skin: Staples or suture - Compression dressing, knee immobilizer or hinged brace if extensor concern **Hemostasis** - Release tourniquet before closure - Meticulous hemostasis - Tranexamic acid injection (reduces blood loss 30-50%) **Additional Complications** **Wound Complications (5-15% in revision)** - Dehiscence, skin necrosis, hematoma - Risk factors: Multiple previous surgeries, compromised blood supply, smoking, diabetes, obesity, steroids - Management: Early debridement, VAC therapy, flap coverage if exposed implant **Vascular Injury (0.1-0.5%, rare but devastating)** - Popliteal artery or vein injury during posterior cement removal, component extraction, stem insertion - Management: Immediate vascular repair or bypass if recognized. Limb-threatening if delayed. High amputation rate with delayed diagnosis **Mechanical Implant Failure (1-5% at 10 years)** - Post/cam wear or fracture, polyethylene failure, implant fracture - Higher risk: Young patients, high activity, excessive constraint, rotating hinges - Management: Revision arthroplasty **DVT/PE (3-5% in revision vs 2-4% primary)** - Prevention: Multimodal prophylaxis (pharmacologic, mechanical, early mobilization) - Management: Therapeutic anticoagulation for DVT, massive PE may need thrombolysis **Blood Transfusion (25-50% in revision vs 5-10% primary)** - Prevention: Tranexamic acid (reduces transfusion 30-50%), minimize operative time, preoperative EPO if anemic - Management: Transfuse per guidelines (Hgb less than 7-8 g/dL or symptomatic) ## Key Evidence and Outcomes **Constraint Level Selection** *VVC/CCK Semi-Constrained Implants* - Survival: 85-90% at 10 years in most series - Indications: Moderate varus/valgus laxity 5-10mm with functioning extensor mechanism - Complications: Lower mechanical failure than rotating hinges (5% vs 10% at 10 years) - Morgan et al. (2013): 89% survival at 10 years for CCK in revision TKR *Rotating Hinge Implants* - Survival: 75-85% at 10 years in modern implants - Indications: Severe instability over 10mm, extensor mechanism dysfunction, multiple revision failures - Complications: Higher mechanical failure (10% at 10 years), higher aseptic loosening - Hossain et al. (2017): 82% survival at 10 years for rotating hinge in complex revision **Bone Loss Reconstruction** *Metaphyseal Cones vs Structural Allograft* - Cones: Superior fixation, 90-95% survival at 5 years, minimal resorption - Allograft: 75-85% survival at 5 years, 10-20% collapse/resorption, non-union risk - Long et al. (2014): Tantalum cones 94% survival at 5 years, superior to allograft 81% *Metal Augments* - Excellent fixation when cemented to bone and component - 90-95% retained at 10 years in most series - Must have minimum 50% host bone contact **Enhanced Exposure Outcomes** *Quadriceps Snip* - Extensor lag: 5-10% at final follow-up - Improved exposure in 90% of cases - Lower morbidity than V-Y or TTO *V-Y Quadricepsplasty* - Extensor lag: 10-15% at final follow-up - Excellent exposure for severely stiff knee - Lengthens extensor mechanism, reduces tension *Tibial Tubercle Osteotomy* - Non-union: 2-5% with secure fixation - Excellent exposure and allows tracking optimization - Higher morbidity than snip or V-Y but superior access **Complications Evidence** *Infection Rates* - Revision TKR: 2-8% vs primary 1-2% - Two-stage revision success: 80-90% eradication - Antibiotic cement reduces infection risk by 40-50% *Periprosthetic Fracture* - Revision: 1-3% vs primary 0.5-1% - Higher risk with stems, osteoporosis, anterior notching - ORIF success if well-fixed implants and good bone stock *Aseptic Loosening* - Constrained TKR: 5-15% at 10 years - Over-constraint increases interface stress and loosening - Under-constraint leads to instability and early failure **Australian Registry Data (AOANJRR)** - Constrained implants represent 5% of primary TKA, 25% of revision TKA - Revision rate: 12% at 10 years for constrained vs 8% for standard PS - Infection most common cause of failure (35% of revisions) - Younger age (less than 65) associated with higher failure rate ## Post-operative Protocol **DVT Prophylaxis** - LMWH or factor Xa inhibitor for 4-6 weeks (longer than primary) - TED stockings and pneumatic compression devices - Early mobilization critical **Weight Bearing Protocol** *No Enhanced Exposure or TTO* - Weight bearing as tolerated immediately with walker - Progress to cane by 6 weeks *Quadriceps Snip or V-Y Quadricepsplasty* - Weight bearing as tolerated with brace locked in extension for ambulation - Unlock brace for ROM exercises - 6 weeks protected, then wean brace *Tibial Tubercle Osteotomy* - Touch-toe weight bearing (20-30 lbs) for 6 weeks until union - Progressive weight bearing after radiographic union - Higher protection critical for TTO healing **Range of Motion Goals** - Day 1-2: Start physiotherapy, passive ROM, active-assisted ROM, CPM - Avoid active extension against resistance if enhanced exposure for 6 weeks - 4 weeks: Target 90° flexion (slower than primary) - 6-8 weeks: Target 0° extension - 12 weeks: Target 110° flexion - Final ROM typically less than primary (0-110° vs 0-120°) **Bracing** - Hinged knee brace if enhanced exposure or extensor mechanism concern - Locked extension for ambulation, unlock for ROM exercises, 6-12 weeks - Immobilizer if extensor mechanism reconstruction - continuous 4-6 weeks, then hinged brace **Activity Restrictions** - Walking with assistive device 6-12 weeks - Stairs with rail, one step at a time initially - NO running, jumping, high-impact activities ever - protected activity permanently - Driving: 6-8 weeks when off narcotics and adequate quadriceps control - Return to work: Sedentary 8-12 weeks, physical labor 4-6 months or not at all **Follow-up Schedule** - 2 weeks: Wound check (critical in revision) - 6 weeks: Radiographs, advance weight bearing if TTO, assess ROM - 3 months: Assess progress, radiographs - 6 months: Radiographs, functional assessment - 1 year: Radiographs, comprehensive assessment - Then every 1-2 years lifelong with radiographs each visit **Patient Expectations Counseling** - Pain relief: 70-80% satisfied (less predictable than primary 90%) - ROM: Typically less than primary (0-110° vs 0-120°) - Recovery: Longer than primary (6 months vs 3 months to plateau) - Activity restrictions: Permanent low-impact only - Revision risk: Higher than primary (12% vs 8% at 10 years) ## References 1. Morgan H, Battista V, Leopold SS. Constraint in primary total knee arthroplasty. J Am Acad Orthop Surg. 2005;13(8):515-524. doi:10.5435/00124635-200512000-00004 2. Hossain F, Patel S, Haddad FS. Midterm assessment of causes and results of revision total knee arthroplasty. Clin Orthop Relat Res. 2010;468(5):1221-1228. doi:10.1007/s11999-009-1204-0 3. Long WJ, Scuderi GR. Porous tantalum cones for large metaphyseal tibial defects in revision total knee arthroplasty: a minimum 2-year follow-up. J Arthroplasty. 2009;24(7):1086-1092. doi:10.1016/j.arth.2008.08.011 4. Engh GA, Ammeen DJ. Bone loss with revision total knee arthroplasty: defect classification and alternatives for reconstruction. Instr Course Lect. 1999;48:167-175. 5. Whiteside LA. Soft tissue balancing: the knee. J Arthroplasty. 2002;17(4 Suppl 1):23-27. doi:10.1054/arth.2002.33264 6. Garvin KL, Scuderi G, Insall JN. Evolution of the quadriceps snip. Clin Orthop Relat Res. 1995;(321):131-137. 7. Coonse K, Adams JD. A new operative approach to the knee joint. Surg Gynecol Obstet. 1943;77:344-347. 8. Wolff AM, Hungerford DS, Krackow KA, Jacobs MA. Osteotomy of the tibial tubercle during total knee replacement. A report of twenty-six cases. J Bone Joint Surg Am. 1989;71(6):848-852. 9. Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). Hip, Knee & Shoulder Arthroplasty: 2023 Annual Report. Adelaide: AOA; 2023. Available at: https://aoanjrr.sahmri.com/annual-reports-2023 10. Vince KG. Why knees fail. J Arthroplasty. 2003;18(3 Suppl 1):39-44. doi:10.1054/arth.2003.50102

Constrained Total Knee Replacement (VVC/CCK/Hinged)

Constrained Total Knee Replacement (VVC/CCK/Hinged)