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Revision Total Knee Replacement - Femoral Component

Surgical technique guide for Revision Total Knee Replacement - Femoral Component - FRCS exam preparation

Core Procedure
intermediate
By OrthoVellum Medical Education Team

Reviewed by OrthoVellum Editorial Team

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High-yield overview

Medial parapatellar arthrotomy via previous incision, with extensile exposure options if needed (quadriceps snip, V-Y turndown, or tibial tubercle osteotomy for severe stiffness) | Core

Primary Indications:

  • Aseptic loosening with AORI Type 2-3 bone loss
  • Polyethylene wear with femoral osteolysis
  • Component malposition (rotation, flexion, sizing)
  • Instability not correctable with poly exchange
  • Periprosthetic fracture with loose component
  • Staged revision for periprosthetic joint infection

AORI Femoral Classification:

  • Type 1: Intact metaphysis - standard revision stems
  • Type 2A: Damaged single condyle - augments needed
  • Type 2B: Damaged both condyles - multiple augments
  • Type 3: Severe metaphyseal deficiency - sleeves, cones, or allograft

Critical Danger Structures

Popliteal Artery and Vein

Location: Posterior to distal femur in popliteal fossa. Separated from posterior capsule by fat pad. Risk during posterior cement removal and posterior capsule release.

Femoral Artery and Vein

Location: Anterior to femur in Hunter canal, transitioning to popliteal vessels at adductor hiatus. Risk with anterior cortical perforation during reaming.

Common Peroneal Nerve

Location: Wraps around fibular neck laterally, 1-2cm distal to fibular head. Risk with valgus correction, lateral release, or leg lengthening greater than 3cm.

Medial Collateral Ligament

Location: Superficial and deep fibers from medial epicondyle to proximal tibia. Risk during medial dissection, epicondylar osteotomy, or aggressive cement removal.

Lateral Collateral Ligament

Location: Lateral epicondyle to fibular head. Risk during lateral releases, lateral condyle augment placement, or lateral approach extension.

Mnemonic

FEMUR

AORI Femoral Bone Loss Classification

Mnemonic

GAPS

Gap Balancing Algorithm in Revision TKA

Positioning and Preparation

Patient Position: Supine on radiolucent table with leg holder or lateral post. Tourniquet applied to upper thigh. Regional or general anesthesia with DVT prophylaxis initiated pre-operatively.

Surgical Approach: Medial parapatellar arthrotomy via previous incision, with extensile exposure options if needed (quadriceps snip, V-Y turndown, or tibial tubercle osteotomy for severe stiffness).

Pre-operative Planning Checklist:

  • Review long-leg alignment films for mechanical axis
  • CT scan for component rotation assessment
  • Measure femoral canal diameter for stem sizing
  • AORI classification from radiographs
  • Have augments, stems, and constraint options available
  • Aspiration to exclude infection (CRP, ESR, synovial WBC)

Operative Technique

Step 1: Exposure and Arthrotomy

Exposure and Arthrotomy: Identify and excise previous scar (use most lateral if multiple scars). Develop full-thickness medial and lateral skin flaps. Perform medial parapatellar arthrotomy extending 5-6cm proximal to superior pole of patella through quadriceps tendon. Excise hypertrophic synovium, scar tissue, and adhesions. Attempt patellar eversion with knee flexion.

Clinical Pearl

Technical Tip: EXAM KEY: In stiff knees with limited flexion (less than 70 degrees), start with lateral gutter release before attempting eversion. Score adhesions in suprapatellar pouch. If patella will not evert safely, perform quadriceps snip (45 degree angle from lateral border of VMO proximally) - adds 10-15 degrees flexion. V-Y turndown for severe stiffness (risk of avulsion). TTO is last resort for ankylosed knees.

Dangers at this step

  • Patellar tendon avulsion during forced eversion in stiff knee
  • Patella fracture through thin or osteopenic bone
  • Quadriceps tendon rupture with aggressive manipulation
  • MCL damage during medial dissection

Step 2: Polyethylene Insert Removal

Polyethylene Insert Removal: Remove polyethylene insert first to gain access to femoral component. Flex knee to 90 degrees and use curved osteotomes or dedicated extraction instruments to disengage locking mechanism. Deliver insert anteriorly. Inspect for wear patterns (anterior, posterior, medial, lateral), backside wear (micromotion), and delamination.

Clinical Pearl

Technical Tip: EXAM KEY: Document wear pattern systematically - asymmetric wear suggests instability or malalignment. Anterior wear in PS design suggests cam-post impingement or excessive posterior slope. Medial wear suggests varus malalignment or MCL insufficiency. Send explanted components for analysis. Photograph for medicolegal documentation and analysis.

Dangers at this step

  • Damaging femoral component surfaces if planning selective revision
  • Losing locking mechanism fragments into joint
  • Scratching well-fixed components during extraction

Step 3: Assessment of Femoral Component Fixation

Assessment of Femoral Component Fixation: Use thin flexible osteotomes to gently test femoral component stability around periphery (distal, anterior, posterior chamfers). Assess for micromotion, tilting, or gross loosening. Compare to pre-operative radiographs showing radiolucent lines, osteolysis, or subsidence. If well-fixed and well-positioned, may consider retaining and revising only tibial side.

Clinical Pearl

Technical Tip: EXAM KEY: Indications to revise well-fixed femoral component: malalignment (greater than 3 degrees varus/valgus, greater than 10 degrees rotation), flexion/extension mismatch, osteolysis requiring access, polyethylene wear into component, need for higher constraint, or instability not correctable with tibial revision alone. If retaining: clean surfaces thoroughly, check for damage or metallosis.

Dangers at this step

  • Creating iatrogenic bone defects while assessing stable component
  • Propagating occult fracture lines during manipulation
  • Missing subtle loosening on clinical exam

Step 4: Femoral Component Removal

Femoral Component Removal: Use thin flexible osteotomes to disrupt cement-bone or bone-implant interface. Work systematically: anterior flange first, then medial and lateral condyles, then posterior condyles. Use Gigli saws for well-fixed cementless components. Apply slap hammer to extraction device attached to femoral component. Remove in flexion with controlled force.

Clinical Pearl

Technical Tip: EXAM KEY: This is the most challenging step - well-fixed cemented components may take 30-45 minutes to remove safely. For ingrown cementless components, oscillating saw or Gigli saws under component are safer than osteotomes (less bone loss). Create small windows in anterior flange if needed to access cement. Preserve bone stock - patience is critical. Consider ultrasonic cement removal for well-fixed cement mantles.

Dangers at this step

  • Supracondylar or condylar fracture (most common intraoperative complication)
  • Posterior cortex perforation with vascular injury
  • MCL or LCL avulsion from epicondyle during extraction
  • Excessive bone loss from aggressive osteotome use
  • Fracture propagation in osteopenic or osteolytic bone

Step 5: Cement and Membrane Removal

Cement and Membrane Removal: Remove all cement, fibrous membrane, and debris down to viable bleeding bone. Use narrow osteotomes, curettes, rongeurs, high-speed burr, and ultrasonic cement removal devices. Work from distal to proximal, anterior to posterior. Preserve cortical shell and condylar bone stock. Remove cement from intercondylar notch and posterior condyles.

Clinical Pearl

Technical Tip: EXAM KEY: Complete cement removal is essential to assess true bone defects and achieve fixation of revision component. Use headlight and magnification. Pulsatile lavage after gross cement removal to clear debris. Cement restrictor deep in femoral canal may require flexible drill or osteotome. Send 5-6 tissue samples for culture and histology (even in presumed aseptic cases - occult infection in 7-10% of aseptic revisions).

Dangers at this step

  • Posterior cortex perforation during posterior cement removal
  • Condylar fracture through weakened or osteolytic bone
  • Thermal injury from high-speed burr (continuous irrigation essential)
  • Creating contained defects into uncontained by aggressive curettage

Step 6: Bone Defect Assessment and Classification

Bone Defect Assessment and Classification: Systematically assess femoral bone defects using AORI classification after all cement removed. Type 1: Intact metaphyseal bone (use standard PS or CCK). Type 2: Damaged metaphysis (use distal or posterior augments 5-15mm). Type 3: Severe deficiency (use large augments, sleeves, allograft, or custom implants). Map defects on distal and posterior condyles, measuring depth and extent.

Clinical Pearl

Technical Tip: EXAM KEY: Common femoral defects - Distal: uncontained defects from loosening or osteolysis. Posterior: notching from malpositioned components or osteolysis. Uncontained defects greater than 5mm need metal augments (screw-fixed if possible). Contained defects less than 5mm can use cement or impaction grafting. Check posterior condyles carefully - often underestimated. Categorize as cavitary (contained) vs segmental (uncontained).

Dangers at this step

  • Underestimating defect depth leading to component undersizing
  • Missing posterior condyle defects (difficult to visualize)
  • Misclassifying uncontained defects as contained

Step 7: Femoral Canal Preparation for Stem (if needed)

Femoral Canal Preparation for Stem (if needed): If using stemmed revision component, prepare femoral canal with flexible reamers starting 1-2mm larger than canal diameter. Ream in 1mm increments to cortical chatter. For press-fit stems, ream to exact stem diameter. For cemented stems, over-ream 2mm. Aim for 4-6cm diaphyseal contact (press-fit) or 8-10cm (cemented). Check alignment with intramedullary rod.

Clinical Pearl

Technical Tip: EXAM KEY: Short stems (50-75mm) for AORI 1-2 provide rotational control and stress shielding reduction. Long stems (100-150mm) for AORI 3 or deficient metaphysis provide fixation and load transfer. Press-fit preferred (better long-term fixation). Offset stems available if canal deformity or malunion. Start small - can always ream larger but cannot make canal smaller. Fluoroscopy helpful to confirm alignment.

Dangers at this step

  • Anterior cortical perforation (femur has anterior bow in sagittal plane)
  • Spiral fracture propagation in osteopenic bone
  • Creating false passage in deformed or sclerotic canals
  • Weakening supracondylar region (fracture risk)

Step 8: Distal Femoral Resection

Distal Femoral Resection: Use intramedullary alignment rod (via stem trial) or extramedullary guide. Set resection perpendicular to mechanical axis in coronal plane (5-7 degrees valgus to anatomic axis). Set 3 degrees external rotation and 0 degrees flexion in sagittal plane. Resect minimum bone necessary to achieve flat surface - typically 2-4mm beyond primary resection. Use distal femoral cutting guide.

Clinical Pearl

Technical Tip: EXAM KEY: Goals of distal cut: perpendicular to mechanical axis (coronal), neutral flexion-extension (sagittal), minimal bone resection. Use intact condyle as reference (usually lateral in varus knees, medial in valgus knees). If massive asymmetric bone loss, may need asymmetric resection or augments. Avoid notching anterior cortex (supracondylar fracture risk). Resection level determines extension gap - balance against flexion gap later.

Dangers at this step

  • Excessive resection compromising metaphyseal bone stock
  • Creating varus or valgus malalignment
  • Anterior cortex notching (supracondylar fracture risk)
  • Resecting into uncontained defect (losing peripheral support)

Step 9: Anterior, Posterior and Chamfer Cuts

Anterior, Posterior and Chamfer Cuts: Set femoral component rotation using posterior condylar axis (3 degrees external rotation), transepicondylar axis (gold standard), or Whiteside line (AP axis). Make anterior, posterior and chamfer cuts with appropriate cutting guides. Size femoral component to avoid anterior notching and optimize posterior condylar offset. Remove posterior osteophytes.

Clinical Pearl

Technical Tip: EXAM KEY: Femoral rotation is critical - internal rotation causes patellar maltracking and medial polyethylene wear. Use transepicondylar axis if landmarks visible, otherwise 3 degrees external to posterior condylar axis. In revision with bone loss, Whiteside line (AP axis) most reliable. Avoid oversizing (notching, overstuffing) and undersizing (instability, poor coverage). Posterior condylar offset affects flexion gap - restore to maintain flexion.

Dangers at this step

  • Anterior cortex notching (stress riser for supracondylar fracture)
  • Malrotation causing patellar maltracking and instability
  • Asymmetric posterior resection creating flexion gap imbalance
  • Damage to collateral ligament origins during chamfer cuts

Step 10: Defect Reconstruction with Augments

Defect Reconstruction with Augments: Based on AORI classification, reconstruct defects with metal augments. Distal femoral defects: use distal augment blocks (5-15mm thickness) secured with screws if possible, fully supported peripherally by host bone. Posterior condyle defects: use posterior augment wedges. Size augments to fill defect completely. Trial to ensure stability and appropriate joint line restoration.

Clinical Pearl

Technical Tip: EXAM KEY: Metal augments are modular blocks or wedges that fill specific defects. Must be fully supported by host bone at periphery (no cantilever). Screw fixation into host bone preferred when possible (improves stability). Cemented to both bone and prosthesis at final implantation. Alternative: modular component systems with built-in augmentation. Avoid structural allograft for femoral defects if possible (high resorption rate).

Dangers at this step

  • Undersizing augments leading to subsidence or collapse
  • Screw penetration into neurovascular structures
  • Incomplete seating creating interface gaps
  • Augment not fully supported leading to failure

Step 11: Trial Reduction and Gap Assessment

Trial Reduction and Gap Assessment: Insert femoral trial with stem (if used) and augments. Insert tibial trial and select polyethylene thickness. Reduce knee and assess through full ROM. Check: extension gap (0 degrees) vs flexion gap (90 degrees) - should be equal plus or minus 2mm. Assess medial-lateral stability with varus/valgus stress (maximum 5mm opening). Check patellar tracking. Test ROM (target 0-110 degrees minimum).

Clinical Pearl

Technical Tip: EXAM KEY: Gap balancing philosophy - Extension gap set by tibial and distal femoral cuts. Flexion gap set by posterior femoral cuts and condylar offset. If extension gap tight: recut tibia or downsize femoral component. If flexion gap tight: add posterior augment or increase tibial slope. If gaps unequal by greater than 2mm, consider revision of cuts or use of constraint (CCK). Assess joint line - should be 2-3cm distal to medial epicondyle.

Dangers at this step

  • Overstuffing extension gap (limited extension, anterior knee pain)
  • Overstuffing flexion gap (limited flexion, PCL impingement if retained)
  • Accepting instability (early failure and dislocation)
  • Joint line elevation greater than 8mm (extensor mechanism dysfunction, instability)

Step 12: Constraint Selection

Constraint Selection: Based on trial assessment, select appropriate constraint level. Posterior Stabilized (PS): if PCL deficient but collaterals intact, good bone stock, balanced gaps. Constrained Condylar Knee (CCK): if MCL or LCL incompetent, flexion-extension gap imbalance, moderate instability. Rotating Hinge Knee (RHK): if severe instability, collateral deficiency, inability to balance gaps. Fixed hinge: salvage only.

Clinical Pearl

Technical Tip: EXAM KEY: Constraint ladder in revision TKR - CR (rarely used in revision) to PS (most revisions) to CCK (varus/valgus laxity greater than 10mm, MCL insufficiency) to RHK (severe instability, cannot balance) to Fixed hinge (salvage, arthrodesis alternative). CCK has taller post and wider box than PS, provides 3-7 degrees varus/valgus constraint. RHK allows axial rotation but prevents varus/valgus tilting. Higher constraint needs longer stems (load transfer).

Dangers at this step

  • Under-constraining (early instability and failure)
  • Over-constraining (interface stress, loosening, reduced ROM)
  • Using RHK without stem (high failure rate from metaphyseal stress)
  • Missing indication for constraint (recurrent instability)

Step 13: Final Implant Preparation and Cementation

Final Implant Preparation and Cementation: Prepare bone surfaces with pulsatile lavage (6-9L) and dry thoroughly with suction and swabs. Mix high-viscosity antibiotic-loaded bone cement (1g vancomycin plus 3.6g tobramycin per 40g cement). Apply cement to bone surfaces and implant using cement gun. For hybrid fixation: press-fit stem, then cement metaphyseal component. For fully cemented: cement stem and component as single construct.

Clinical Pearl

Technical Tip: EXAM KEY: Third generation cementing technique - clean dry bone, pressurization, cement gun application, component insertion during dough phase, removal of excess before polymerization. Hybrid fixation (press-fit stem, cemented metaphyseal component) is popular - combines biological fixation with immediate stability. Use antibiotic cement in all revisions (even aseptic) - reduces infection risk. Apply cement to augments and bone-augment interface.

Dangers at this step

  • Cement extrusion posteriorly into neurovascular structures
  • Air entrapment creating weak spots in cement mantle
  • Premature cement polymerization before component seated
  • Inadequate cement penetration into cancellous bone

Step 14: Femoral Component Insertion and Polyethylene Selection

Femoral Component Insertion and Polyethylene Selection: Insert stem first if hybrid technique. Apply cement to femoral bone surfaces and undersurface of component. Insert femoral component with firm steady pressure, ensuring proper rotation (aligned with transepicondylar axis), AP position (no anterior notching, adequate posterior coverage), and seating. Pressurize cement. Remove excess. Hold until polymerized. Select and insert final polyethylene after cement set.

Clinical Pearl

Technical Tip: EXAM KEY: Femoral component position checks - Rotation: 3 degrees external to posterior condylar axis or parallel to transepicondylar axis. Flexion: neutral (0 degrees or slight flexion acceptable, avoid extension). Sizing: maximize coverage without notching, restore condylar offset. Poly thickness: 10mm minimum for PS, 12-15mm for CCK (taller post), 15-20mm for RHK. Lock poly securely and confirm cannot be removed by traction.

Dangers at this step

  • Malrotation (internal rotation causes patellar problems and wear)
  • Anterior notching (supracondylar fracture risk)
  • Incomplete seating leaving gaps under component
  • Polyethylene insert not fully locked (catastrophic failure)

Step 15: Final Assessment, Closure and Post-Operative Protocol

Final Assessment, Closure and Post-Operative Protocol: Final check: ROM 0-110 degrees minimum, stable throughout arc, no lift-off with varus/valgus stress, patellar tracking central. Remove all cement, debris with lavage. Achieve hemostasis. Insert drain if significant dead space. Close capsule and extensor mechanism with strong interrupted sutures (No.2 or No.5) in flexion. Close layers and skin. Apply compression dressing with knee in extension.

Clinical Pearl

Technical Tip: EXAM KEY: Post-operative protocol - Tranexamic acid 1g IV at induction and closure. Ice and elevation. TED stockings and chemical thromboprophylaxis (LMWH or DOAC) for 35 days. IV antibiotics 24h. Early mobilization day 1 with physiotherapy - WBAT with walking frame. CPM if available (0-60 degrees advancing to 0-90 degrees by week 2). Remove drain 24-48h. Radiographs: AP, lateral, skyline check alignment, component position, no fracture. Discharge day 4-7 to rehabilitation. Follow-up 6 weeks, 3 months, 1 year, then annually.

Dangers at this step

  • Wound dehiscence (higher risk with extensile exposures)
  • Deep infection (5-10% risk in revision surgery)
  • Supracondylar fracture during early mobilization
  • Extensor mechanism failure or rupture
  • Persistent instability or stiffness requiring re-revision
  • Neurovascular complications (DVT, PE, nerve palsy)

Complications

Femoral Revision TKA Complications

Clinical Decision Scenarios

Use these scenarios to practise clinical reasoning and management decisions

CLINICAL SCENARIOStandard

CLINICAL PROMPT

"A 72-year-old woman presents 12 years after primary TKA with progressive pain and instability. Radiographs show a loose femoral component with AORI Type 2B bone loss (both condyles affected). How do you approach this revision?"

PRACTICAL APPROACH
This is an aseptic femoral component revision with AORI Type 2B bone loss affecting both condyles. My systematic approach would be: **Pre-operative Workup:** - Confirm aseptic loosening: CRP, ESR, joint aspiration with synovial WBC and differential - Long-leg alignment films for mechanical axis assessment - CT scan for precise bone loss quantification and femoral rotation assessment - Order modular revision system with full range of augments, stems, and constraint options **Intraoperative Classification:** - AORI Type 2B indicates damaged metaphysis with both condyles affected - Requires augmentation strategy for distal and possibly posterior condyles - Likely needs stemmed component for additional fixation **Defect Reconstruction Strategy:** - After component removal and cement debridement, map defects precisely - Distal condyle defects: metal augment blocks (5-15mm available) - Posterior condyle defects: posterior wedge augments - Ensure augments fully supported by host bone peripherally **Component Selection:** - Stemmed revision component (75-100mm) for AORI Type 2B - Constraint based on gap balancing: start with PS, increase to CCK if instability - Press-fit stem preferred for diaphyseal fixation **Joint Line Restoration:** - Critical to restore within 8mm of native level - Use medial epicondyle as landmark (joint line 2-3cm distal) - Augments help restore joint line while filling defects **Gap Balancing:** - Extension gap set by distal resection plus augments - Flexion gap set by posterior condyle restoration - Target equal gaps plus or minus 2mm
CLINICAL SCENARIOStandard

CLINICAL PROMPT

"During femoral component removal, you create a supracondylar fracture that extends into the diaphysis. The fracture is displaced with a separate butterfly fragment. How do you manage this intraoperatively?"

PRACTICAL APPROACH
This is a significant intraoperative complication requiring immediate decision-making. A displaced supracondylar fracture with butterfly fragment during revision represents a surgical challenge requiring combined fixation and revision strategies. **Immediate Assessment:** - Stop component removal and assess fracture extent - Determine if fracture is stable or unstable - Evaluate remaining metaphyseal and diaphyseal bone quality - Check neurovascular status **Classification and Decision:** - This is effectively a Lewis-Rorabeck Type III equivalent (fracture around loose prosthesis) - Unstable fracture requires both fracture fixation and revision **Intraoperative Management Strategy:** 1. **Fracture Reduction:** - Gently reduce displaced fragments - Reduce and provisionally fix butterfly fragment with cerclage wire - Assess overall alignment 2. **Long-Stem Component Selection:** - Select long diaphyseal-engaging stem (150-200mm) - Stem must bypass fracture by 2 cortical diameters (minimum 8-10cm) - Press-fit preferred if bone quality permits 3. **Combined Fixation:** - Lateral locking plate for additional stability - Cerclage wires or cables around fracture site - Plate spans entire fracture zone plus 2 cortical diameters distally 4. **Augmentation if Needed:** - Use augments to reconstruct metaphyseal defects as planned - Component provides stable reference for plate positioning **Post-operative Protocol:** - Protected weight-bearing 6-12 weeks - Serial radiographs at 2, 6, 12 weeks to monitor healing - Progress rehabilitation based on fracture healing evidence
CLINICAL SCENARIOStandard

CLINICAL PROMPT

"You are revising a TKA in a patient with rheumatoid arthritis. Intraoperatively, after balancing the gaps with trials, you find greater than 15mm of varus-valgus laxity in extension despite using a PS design. What is your approach?"

PRACTICAL APPROACH
This scenario describes severe collateral ligament insufficiency in a revision TKA, which is common in rheumatoid arthritis due to chronic synovitis and ligament attenuation. A varus-valgus laxity greater than 15mm cannot be managed with PS design and requires higher constraint. **Assessment of Instability Pattern:** - 15mm varus-valgus laxity indicates MCL or combined collateral insufficiency - Rheumatoid patients often have global ligamentous laxity - Assess both extension and flexion stability (may be worse in one position) - Check for bone loss contributing to instability **Constraint Ladder Application:** - PS provides minimal varus-valgus constraint (0-3 degrees) - CCK provides 3-7 degrees varus-valgus constraint - may be inadequate for 15mm laxity - RHK (Rotating Hinge Knee) provides complete varus-valgus stability - appropriate choice here **Switching to Rotating Hinge Knee:** 1. **Component Selection:** - RHK system with modular options - Long stems mandatory (100-150mm) for both femur and tibia - Stem must engage diaphysis for load transfer (metaphysis cannot support hinge forces) 2. **Stem Fixation:** - Press-fit stems preferred if bone quality permits - Cemented stems if osteopenic (common in RA) - Hybrid fixation: press-fit stem with cemented metaphyseal component 3. **Augmentation Strategy:** - Assess bone loss after committing to RHK (may need different augments) - RHK systems have built-in options for bone loss 4. **Polyethylene Selection:** - Thicker poly typically required for RHK (15-20mm) - Ensure proper hinge engagement and rotation **Post-operative Considerations for RA:** - Higher infection risk due to immunosuppression - Consider withholding biologics perioperatively - May need prolonged protected weight-bearing if bone quality poor - Close rheumatology liaison for disease management

Evidence Base

Bone loss with revision TKA: defect classification and alternatives for reconstruction (AORI)

Level V
Engh GA, Ammeen DJ • Instructional Course Lectures (Anderson Orthopaedic Research Institute)
Clinical Implication: AORI grading drives the entire reconstruction algorithm: Type 1-2 defects are managed with augments and shorter stems, while Type 3 deficiency mandates metaphyseal fixation (cones/sleeves) or allograft with diaphyseal-engaging stems.
Verify on PubMed (PMID 10098042)

Malrotation causing patellofemoral complications after total knee arthroplasty

Level III
Berger RA, Crossett LS, Jacobs JJ, Rubash HE • Clinical Orthopaedics and Related Research
Clinical Implication: Confirms why femoral component rotation referenced to the transepicondylar axis is critical in revision: internal rotation drives patellar maltracking and medial wear, and a malrotated but well-fixed component is a valid indication to revise.
Verify on PubMed (PMID 9917679)

Strategies for severe bone loss in revision knee arthroplasty: systematic review and meta-analysis

Level III
Byttebier P, Dhont T, Pintelon S, Rajgopal A, Burssens A, Victor J • The Journal of Arthroplasty
Clinical Implication: For AORI Type 2B-3 femoral defects, porous metaphyseal cones or sleeves provide durable metaphyseal fixation and are first-line over structural allograft in most adults; graft is reserved for very large segmental loss or younger patients.
Verify on PubMed (PMID 35271982)

Implant survivorship, function and complications of rotating-hinge knee implants: systematic review

Level III
Xu J, von Fritsch L, Sabah SA, Price AJ, Alvand A • Knee Surgery & Related Research
Clinical Implication: Rotating hinge restores stability in global collateral insufficiency or unbalanceable gaps, but revision-setting 10-year survivorship near 65% justifies reserving it for cases where lesser constraint cannot achieve stability.
Verify on PubMed (PMID 35246278)

Condylar constrained versus rotating hinge implants in revision knee arthroplasty: meta-analysis

Level III
Stroobant L, de Taeye T, Byttebier P, Van Onsem S, Jacobs E, Burssens A, Victor J • Knee Surgery, Sports Traumatology, Arthroscopy
Clinical Implication: When collaterals are competent enough to be balanced, a CCK gives equivalent mid-term survival to a hinge with less constraint-related interface stress; escalate to RHK only when collateral function is absent or gaps cannot be balanced.
Verify on PubMed (PMID 37747534)

Guidelines, Registries & Global Practice

Registry survivorship of revision TKA (implant survival to re-revision): National joint registries consistently report higher re-revision and lower survivorship for revision TKA than for primary TKA. The National Joint Registry (NJR, England/Wales/NI), the American Joint Replacement Registry (AJRR), the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), the Swedish Arthroplasty Register and the New Zealand Joint Registry all identify infection, instability and aseptic loosening as the dominant modes of failure after revision, reinforcing meticulous gap balancing, appropriate constraint and metaphyseal fixation.

Constraint and fixation (cross-society): There is global consensus across AAOS (US), BOA/BASK (UK) and EFORT/European practice on the constraint ladder principle - use the least constraint that achieves stability, and lengthen stems as constraint and bone loss increase to transfer load to the diaphysis. Hybrid fixation (cemented metaphysis with press-fit diaphyseal stem) and fully cemented stems are both accepted; the choice is guided by bone quality and canal geometry rather than a single national standard.

Infection workup: Diagnosis of periprosthetic joint infection before revision follows internationally harmonised criteria (Musculoskeletal Infection Society / International Consensus Meeting and EBJIS definitions), combining serum CRP/ESR, synovial white-cell count and differential, culture and histology. Routine intra-operative cultures (5-6 samples) are recommended even in presumed aseptic revision because occult infection is found in a meaningful minority.

Thromboprophylaxis and tranexamic acid: AAOS and NICE both endorse risk-stratified chemical and mechanical VTE prophylaxis after major knee arthroplasty; routine peri-operative tranexamic acid is recommended across guidelines to reduce blood loss and transfusion. Specific agent and duration vary by national guidance and patient risk.

References

  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. PMID: 10098042.

  2. Berger RA, Crossett LS, Jacobs JJ, Rubash HE. Malrotation causing patellofemoral complications after total knee arthroplasty. Clin Orthop Relat Res. 1998;(356):144-153. PMID: 9917679. doi:10.1097/00003086-199811000-00021.

  3. Byttebier P, Dhont T, Pintelon S, Rajgopal A, Burssens A, Victor J. Comparison of different strategies in revision arthroplasty of the knee with severe bone loss: a systematic review and meta-analysis of clinical outcomes. J Arthroplasty. 2022;37(6S):S371-S381.e4. PMID: 35271982. doi:10.1016/j.arth.2022.02.103.

  4. Xu J, von Fritsch L, Sabah SA, Price AJ, Alvand A. Implant survivorship, functional outcomes and complications with the use of rotating hinge knee implants: a systematic review. Knee Surg Relat Res. 2022;34(1):9. PMID: 35246278. doi:10.1186/s43019-022-00138-2.

  5. Stroobant L, de Taeye T, Byttebier P, Van Onsem S, Jacobs E, Burssens A, Victor J. Condylar constrained and rotating hinged implants in revision knee arthroplasty show similar survivorship and clinical outcome: a systematic review and meta-analysis. Knee Surg Sports Traumatol Arthrosc. 2023;31(12):5365-5380. PMID: 37747534. doi:10.1007/s00167-023-07572-z.

  6. Whiteside LA, Arima J. The anteroposterior axis for femoral rotational alignment in valgus total knee arthroplasty. Clin Orthop Relat Res. 1995;(321):168-172. PMID: 7497664.

  7. Fehring TK, Odum S, Griffin WL, Mason JB, Nadaud M. Early failures in total knee arthroplasty. Clin Orthop Relat Res. 2001;(392):315-318.

  8. Morgan HD, Battista V, Leopold SS. Constraint in primary total knee arthroplasty. J Am Acad Orthop Surg. 2005;13(8):515-524.

  9. Parvizi J, Zmistowski B, Berbari EF, 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.

  10. Rorabeck CH, Taylor JW. Classification of periprosthetic fractures complicating total knee arthroplasty. Orthop Clin North Am. 1999;30(2):209-214.

Revision TKA Femoral Component - Exam Summary

Clinical summary