High Yield Overview

TKA REVISION - TIBIAL COMPONENT WITH CONES

Complex metaphyseal reconstruction | High-difficulty revision arthroplasty

Critical Danger Structures - Knee-Specific

Popliteal Neurovascular Bundle

Location: 10-15mm posterior to posterior capsule at joint line Protection: Retract posteriorly with bent Hohmann, avoid excessive posterior dissection, flex knee to relax structures, monitor posterior cortex during tibial preparation

Common Peroneal Nerve

Location: Posterolateral corner, winds around fibular neck 30-40mm distal to joint Protection: Avoid lateral release beyond popliteus corner, release contractures slowly, limit valgus correction to gradual increments, decompress at fibular neck if stretch anticipated

Medial Collateral Ligament Origin

Location: Medial femoral condyle, 10mm proximal and posterior to joint line Protection: Subperiosteal dissection during medial exposure, preserve deep fibers during parapatellar arthrotomy, avoid excessive medial soft tissue stripping

Extensor Mechanism

Location: Quadriceps tendon, patella, patellar tendon complex Protection: Use extensile approaches early if limited eversion, protect patellar blood supply (lateral geniculate), avoid aggressive lateral release, consider tubercle osteotomy for stiff knees

Tibial Cortex (Medial/Lateral)

Location: Metaphyseal and diaphyseal cortices during component removal and stem insertion Protection: Avoid aggressive osteotome use, use flexible reamers for stems, sequential reaming 0.5mm increments, intraoperative fluoroscopy for stem trajectory

Mnemonic

CONESCONES Indications

Mnemonic

STABLESTABLE Cone Fixation Principles

Patient Assessment

Exam Pearl

Critical Planning Decision: Cone selection based on AORI classification - Type 2B requires single cone, Type 3 may need dual cones or custom reconstruction. Templating determines cone size (typically 35-55mm tibia), stem length (100-150mm), and augment needs.

Indications for Tibial Cone Reconstruction

Primary Indications:

AORI Type 2B defects: Damaged metaphyseal bone, one femoral or tibial condyle compromised
AORI Type 3 defects: Deficient metaphyseal bone, both condyles compromised
Periprosthetic fracture with metaphyseal bone loss requiring fixation
Failed structural allograft with residual defect
Septic revision after debridement (staged, infection eradicated)

Relative Indications:

AORI Type 2A with poor bone quality (osteoporosis, multiple revisions)
Combined supracondylar femur fracture with tibial bone loss
Hinged/constrained revision requiring enhanced tibial support

Contraindications

Absolute:

Active infection (stage for spacer first, treat infection)
Inadequate host bone for cone press-fit (severely deficient cortices)
Uncorrectable vascular insufficiency
Non-ambulatory patient with low functional demand

Relative:

Severe osteoporosis (consider cemented augments, longer stems)
Extensor mechanism disruption (repair/reconstruct first)
Medical comorbidities precluding 2+ hour surgery
Patient age less than 50 years (consider structural allograft if young, active)

Imaging Requirements

Critical Yield Data

AP/Lateral XR

CT Scan

Metal Subtraction MRI

Templating Strategy

Cone Sizing:

Measure metaphyseal width on CT (mediolateral and AP dimensions)
Select cone 2-3mm smaller than metaphyseal diameter (40-55mm for tibia)
Cone height determines baseplate position (typically 15-25mm depth)
Plan for symmetric or asymmetric defects (may need medial vs lateral placement)

Stem Selection:

Length: Bypass cone by 2 cortical diameters (typically 100-150mm total stem)
Diameter: Fill 80% canal at isthmus (10-18mm common sizes)
Type: Cemented vs cementless (cemented preferred if poor bone quality)
Offset: Match anatomic tibial offset (standard vs offset stems)

Augment Planning:

Wedge augments for peripheral defects (5-20mm thickness)
Block augments for central defects (5-15mm)
Plan for 3-10mm tibial polyethylene minimum thickness

Operative Steps - Detailed Approach

Step 1: Skin Incision and Approach Selection

Technique:

Use prior midline incision if present (most lateral if multiple scars)
Create full-thickness flaps (avoid beveling, preserves blood supply)
Extend proximally to mid-thigh, distally to tibial tubercle or beyond
Identify extensor mechanism, assess scar tissue, plan arthrotomy

Exam Pearl

Vascular Assessment: Palpate pedal pulses preoperatively. If multiple prior incisions, excise most medial scar en bloc with arthrotomy to preserve lateral genicular blood supply. Skin ischemia risk 8-12% with revision surgery.

Skin Necrosis Prevention

Avoid multiple skin flaps - excise intermediate scars
Use full-thickness flaps only (no subcutaneous dissection)
Handle skin gently with skin hooks (no crushing clamps)
Consider plastic surgery consultation if concern about closure

Step 2: Extensile Exposure Selection

Standard Medial Parapatellar:

Attempt first if no previous extensile approach
Release medial capsule and MCL deep fibers subperiosteally
Elevate patella laterally - if does not evert easily, extend exposure

Rectus Snip (Prefer for mild-moderate stiffness):

45-degree proximal-lateral incision in quadriceps tendon
2-3cm length from superomedial pole of patella
Preserves vastus medialis obliquus fibers
Repair directly at closure with #2 FiberWire figure-of-8

Tibial Tubercle Osteotomy (Best for severe stiffness, young patients):

Mark 5-6cm x 1.5cm osteotomy lateral to tibial crest
Microsagittal saw with 4-5mm depth (preserves posterior cortex)
Thin osteotome to crack posterior cortex
Reflect tubercle proximally with patellar tendon attached
Fix at closure with 2-3 bicortical screws or cerclage wires

VY Quadricepsplasty (Last resort, older/low-demand patients):

Invert V-incision in quadriceps tendon (apex 6-8cm proximal to patella)
Reflect patella distally, gaining 3-5cm length
Repair in Y-configuration with #5 Ethibond or FiberWire
Protected weight-bearing 6 weeks, high complication rate (10-15% disruption)

Exam Pearl

Examiner Question: "How do you decide between extensile options?" Answer: "Assess patella eversion intraoperatively with knee flexed 90 degrees. If patella does not evert lateral to midline without tension, extend exposure. Rectus snip preferred (lowest complication rate 2-3%), tibial tubercle if severe patella baja or young patient needing quadriceps preservation, VY turndown reserved for ankylosed knees in elderly patients with low functional demands."

Extensor Mechanism Rupture

Risk 1-2% with standard approach, 5-8% with extensile
Release slowly with knee flexion, not forced eversion
Consider extensile approach early if resistance encountered
Protect lateral geniculate blood supply (avoid excessive lateral release)

Step 3: Component Removal - Femoral First

Rationale: Remove femoral component first for access to tibial component

Technique:

Disrupt cement-bone interface with narrow osteotomes
Use curved osteotomes posteriorly (avoid popliteal vessels)
May use oscillating saw for anterior flange cement
Extract femoral component with universal extractor
Remove all cement (high-speed burr, ultrasonic devices)
Preserve bone stock (avoid aggressive gouging)

Posterior Cortex Perforation

Thin posterior femoral condyle cortex (3-5mm)
Use Gigli saw or curved osteotome with direct visualization
Avoid power burr posteriorly (thermal necrosis, perforation risk)
Protect popliteal vessels with posterior retractor

Step 4: Tibial Component Exposure

Technique:

Flex knee maximally (allows elevation off posterior structures)
Elevate medial and lateral soft tissue sleeves (preserve MCL/LCL origins)
Insert bent Hohmann retractors posteromedially and posterolaterally
Protect popliteal vessels (posterior retractors rest on bone, not soft tissue)

Step 5: Tibial Component Removal

Cement Disruption:

Microsagittal saw along periphery of baseplate (risk cortical damage)
Osteotomes at bone-cement interface (start anteriorly, work posteriorly)
Gigli saw for posterior cement if accessible
Gentle mallet taps (avoid violent impacts causing fracture)

Stem Removal:

If cemented stem: ultrasonic cement removal around proximal stem, flexible osteotomes down canal
If press-fit stem: tap out with slotted extractor or drill multiple access holes in baseplate
Avoid cortical perforation (use fluoroscopy if difficult extraction)

Exam Pearl

Periprosthetic Fracture During Removal: Occurs 5-8% of revisions. Prevent with careful technique, sequential loosening, fluoroscopy. If fracture occurs: classify (intraoperative vs postoperative), stable vs unstable. Manage with longer stems (bypass fracture 2 cortical diameters), cerclage wires/cables, possible lateral locking plate if unstable.

Tibial Cortex Fracture

Risk highest at metaphyseal-diaphyseal junction (stress riser)
Stop if crack visualized or heard
Manage with cerclage cables, longer stem bypass
Consider lateral locking plate if propagates
Document intraoperatively (medicolegal, postoperative management)

Step 6: Cement Removal and Defect Assessment

Cement Extraction:

Remove all cement to bleeding bone (essential for cone osseointegration)
Use combination: hand tools, high-speed burr, ultrasonic removal
Pulse lavage between steps (clears debris, identifies retained cement)
Preserve cortical bone (avoid aggressive burring)

Defect Assessment:

Classify using AORI system:
- Type 1: Intact metaphyseal bone (no cone needed)
- Type 2A: Damaged metaphyseal bone, one condyle (augment may suffice)
- Type 2B: Damaged metaphyseal bone, both condyles (cone indicated)
- Type 3: Deficient metaphyseal bone, loss of structural support (cone required)

Step 7: AORI Classification and Cone Selection

Measurement:

Assess defect depth with depth gauge or ruler (5-30mm common)
Assess bone quality (firm cortical rim vs soft cancellous)
Identify contained vs uncontained defects
CT template confirms cone size (35-55mm for tibia, most common 40-50mm)

Cone Indication Decision:

Type 2B/3: Cone indicated
Type 2A with poor bone: Consider cone vs large augment
Type 1: No cone, proceed with standard revision baseplate

Step 8: Cone Selection and Planning

Cone Characteristics:

Porous tantalum (trabecular metal) or titanium porous coating
Porosity 80%, modulus 3 GPa (similar to bone, reduces stress shielding)
Available sizes: 35mm, 40mm, 45mm, 50mm, 55mm (tibia)
Symmetric or asymmetric designs (medial/lateral specific for some systems)

Size Selection:

Measure metaphyseal diameter on CT (typically 50-70mm)
Select cone 2-5mm smaller than metaphyseal diameter (press-fit, not loose)
Larger cone provides more surface area (better fixation) but requires more bone removal
Balance: maximize contact, minimize healthy bone sacrifice

Step 9: Metaphyseal Preparation - Serial Reaming

Reaming Technique:

Start with smallest reamer (usually 30-35mm)
Ream until bleeding bone (endpoint: punctate bleeding, firm feel)
Advance in 2.5mm increments (avoid aggressive single-step jumps)
Ream to planned cone size minus 2mm (trial cone undersized)
Preserve cortical rim (avoid eccentric reaming causing perforation)

Exam Pearl

Bleeding Bone Endpoint Critical: Non-bleeding sclerotic bone will not osseointegrate. Must ream to bleeding cancellous bone with firm cortical rim. Use pulse lavage to visualize bleeding (tourniquets deflated if used). Intraoperative decision: if inadequate bleeding, consider cemented technique or structural allograft.

Cortical Perforation During Reaming

Risk medial/lateral cortex perforation (thin metaphyseal bone)
Use sequential reaming with frequent assessment
Perforation less than 1cm: acceptable, pack morselized graft
Perforation greater than 1cm: consider plate fixation, structural allograft strut
Document on operative note (affects postoperative weight-bearing)

Step 10: Cone Trial and Fit Assessment

Trial Insertion:

Insert trial cone 2mm smaller than final planned size
Rotate to optimize contact (asymmetric defects may need specific orientation)
Assess stability: manual pressure, no gross motion (micromotion less than 50 microns acceptable)
Impaction may be needed (light mallet taps, not heavy force)
Burr high spots if trial does not seat (preserves more bone than over-reaming)

Fit Criteria:

60-70% surface contact minimum (visual estimate, firm feel)
Flush seating at metaphyseal rim (not proud, not recessed more than 2-3mm)
Stable to manual stress (no rocking)
Adequate bone quality (firm cortical rim, bleeding cancellous bone)

Step 11: Cone Stability Verification

Intraoperative Testing:

Attempt to rotate cone with impactor (should not move)
Apply axial load (push hard on cone, should not subside)
Rock medially-laterally (should not toggle)
If unstable: upsize cone 2.5mm OR ream additional 1mm if undersized

Fluoroscopic Confirmation:

AP view: symmetric position, no medial/lateral tilt
Lateral view: appropriate depth, parallel to joint line
Assess for occult fractures from impaction

Exam Pearl

Press-Fit vs Cemented Cone Debate: Literature favors press-fit (80% osseointegration at 2 years, 75-80% survivorship at 10 years). Cemented cones have higher failure rates (50-60% at 10 years, no biological fixation). Cement only if absolutely unstable or severe osteoporosis precludes press-fit.

Step 12: Morselized Bone Graft Application

Graft Packing Technique:

Pack morselized autograft (reaming debris) or allograft around cone periphery
Fill gaps between cone and host bone (enhances contact, promotes ingrowth)
Avoid graft between cone and baseplate interface (causes instability)
Impaction grafting technique (sequential packing, impaction, packing)

Graft Sources:

Autograft: femoral/tibial reaming debris (preferred, no disease transmission)
Allograft: morselized cancellous chips (if insufficient autograft)
Avoid synthetic (calcium phosphate, hydroxyapatite) in this application

Step 13: Tibial Baseplate Insertion with Stem

Baseplate Selection:

Modular revision baseplate with cone-compatible design (flat undersurface)
Select appropriate mediolateral width (match tibial anatomy, typically 70-85mm)
Anteroposterior coverage (avoid overhang medially, posteriorly)
Rotation: align with tibial tubercle, ankle mortise

Stem System:

Stem length: bypass cone by 2 cortical diameters (typically 100-150mm total)
Stem diameter: fill 80% canal at isthmus (sequential flexible reaming to size)
Cemented vs cementless stem:
- Cemented: if poor bone quality, need immediate stability, older patient
- Cementless: if good bone quality, younger patient, desire biological fixation

Insertion Technique:

Trial baseplate with trial stem on cone
Assess rotation (tibial tubercle alignment), mediolateral position (central on cone)
Remove trial, insert final cone (impaction to stable endpoint)
Insert final baseplate-stem construct onto cone
Ensure baseplate flush on cone (no gaps, no rocking)

Stem Malalignment

Varus/valgus mismatch between stem and tibial canal causes cortical impingement
Use flexible reamers (follow canal anatomy, not rigid guides)
Fluoroscopy confirms stem trajectory (AP and lateral views)
If cortical contact: downsize stem or offset stem options
Perforation risk 2-3% (requires longer stem bypass, possible plate fixation)

Step 14: Stem Engagement and Load Sharing

Biomechanical Principles:

Stem bypasses cone distally by 2 cortical diameters (distributes load, prevents stress concentration)
Load sharing: metaphyseal cone (30-40% load), stem (40-50% load), baseplate-bone interface (10-20%)
Stem prevents cone subsidence (backup fixation if cone integration incomplete)

Stem Fixation Verification:

Press-fit stems: firm impaction, stable to manual stress
Cemented stems: third-generation technique, cement gun, finger packing proximally
Fluoroscopy confirms depth (stem tip 2 cortical diameters beyond cone apex)

Step 15: Baseplate Fixation to Cone

Cemented Technique (most common):

Apply thin cement layer to cone superior surface (mantle 1-2mm)
Insert baseplate onto cone with stem in canal
Hold compression 8-10 minutes (cement curing)
Remove extruded cement (avoid leaving debris)

Cementless Technique (younger patients, good bone):

Direct impaction of baseplate onto cone (taper-lock or screw fixation)
Some systems use central screw through baseplate into cone
Relies on press-fit stability and osseointegration

Exam Pearl

Baseplate-Cone Interface Critical: Gap greater than 2mm causes micromotion, failure risk. Ensure flush contact intraoperatively. Cement mantle technique creates stable interface. Some surgeons avoid cement at this interface (prefer screw fixation), literature mixed - cement probably safer for immediate stability.

Step 16: Modular Augments for Residual Defects

Augment Selection:

Assess residual bone defects after cone/baseplate insertion
Wedge augments: peripheral/slope defects (medial/lateral, 5-20mm thickness)
Block augments: central defects (5-15mm thickness)
Augments cement to baseplate (creates monolithic construct)

Application Technique:

Trial augments to verify size and position
Cement augment to baseplate (avoid cement at augment-bone interface)
Press firmly during cement curing (ensure no gaps)
Goal: restore joint line height (measure from fibular head, adductor tubercle)

Joint Line Restoration:

Normal joint line: 25mm distal to medial epicondyle (femur), 10mm distal to fibular head (tibia)
Patella baja risk if joint line elevated (Insall-Salvati ratio less than 0.8)
Compromised flexion if joint line lowered excessively

Step 17: Polyethylene Selection and Insertion

Polyethylene Thickness:

Minimum 10mm thickness (wear considerations, especially if young patient)
Thicker inserts (12-25mm) for ligamentous laxity, bone loss requiring buildup
Highly cross-linked polyethylene (HXLPE) preferred (reduces wear 90% vs conventional)

Constraint Selection:

Posterior-stabilized: if collateral ligaments intact, stable flexion-extension gaps
Constrained condylar knee (CCK): if mild MCL/LCL laxity (5-10mm in extension)
Rotating hinge: if severe ligamentous insufficiency, gross instability
Avoid over-constraining (increases constraint = increases bone-implant interface stress = higher loosening risk)

Trialing and Assessment:

Trial femoral and polyethylene components
Assess stability (Lachman, varus-valgus stress at 0 and 20 degrees flexion)
Assess flexion-extension gaps (should be balanced within 2mm)
Range of motion to 110-120 degrees minimum (limited by soft tissues, not impingement)
Patellar tracking (no tilt, subluxation, ensure lateral release adequate if needed)

Final Insertion:

Cement femoral component if revision femoral work done (technique per system)
Lock polyethylene into tibial baseplate (ensure secure, no lift-off)
Irrigate copiously (remove all debris, cement fragments)
Final stability check and range of motion

Exam Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOStandard

EXAMINER

"A 68-year-old presents with pain and loosening of their tibial component 8 years after primary TKA. Radiographs show 15mm of medial tibial subsidence with both condyles compromised. How would you classify this defect and what reconstruction options would you consider?"

EXCEPTIONAL ANSWER

This is an AORI Type 2B or 3 defect based on the description of both condyles compromised with significant subsidence. AORI 2B indicates damaged metaphyseal bone affecting both condyles but with some structural support remaining, while Type 3 represents deficient metaphyseal bone with loss of structural integrity. At 15mm subsidence with both condyles involved, this likely represents a Type 2B or Type 3 defect requiring metaphyseal reconstruction. My reconstruction options in order of preference would be: (1) Porous metal tibial cone with stemmed baseplate - provides biological fixation through osseointegration, 75-80% survivorship at 10 years, indicated for Type 2B/3 defects; (2) Modular metal augments with stemmed baseplate - acceptable for Type 2A/B but lower survivorship 60-70% at 10 years without cone; (3) Structural allograft - biology-friendly but higher failure rate 40-50% at 10 years, resorption/collapse risk; (4) Custom implant or hinged prosthesis if massive bone loss precludes cone fixation. For this patient, I would plan for a porous metal tibial cone reconstruction with cemented stemmed baseplate, as this provides the best combination of biological fixation and mechanical stability for Type 2B/3 defects.

VIVA SCENARIOStandard

EXAMINER

"During cone impaction for a Type 3 tibial defect, you achieve what appears to be good press-fit stability. However, fluoroscopy shows the cone is 5mm proud relative to the metaphyseal rim. How would you address this situation?"

EXCEPTIONAL ANSWER

A cone sitting 5mm proud indicates inadequate seating and raises concern for insufficient metaphyseal contact and potential instability. This must be addressed intraoperatively. My approach would be: First, reassess the reamed cavity - the cone may be undersized relative to the defect depth, or there may be inadequate reaming proximally. Second, remove the cone and inspect for soft tissue interposition, retained cement fragments, or sclerotic bone preventing full seating - use pulse lavage to clear debris and reassess bone quality. Third, if bone quality is adequate, ream an additional 2-3mm deeper to allow cone to seat flush with the metaphyseal rim - the goal is flush seating or maximum 2mm proud, not 5mm. Fourth, if after deeper reaming the cone still cannot seat flush, consider upsizing the cone by 2.5-5mm which may provide better contact and stability. Fifth, if none of these maneuvers achieve flush seating with stability, I would abandon the cone technique and use an alternative such as stepped augments with long stemmed component or structural allograft. The critical principle is that a cone sitting 5mm proud will have inadequate surface contact (likely less than 40-50% vs required 60-70% minimum), high risk of micromotion preventing osseointegration, and probable early failure through subsidence or loosening.

VIVA SCENARIOStandard

EXAMINER

"Post-operatively, a patient with tibial cone reconstruction develops progressive pain and radiographs at 1 year show a 2mm lucent line around the entire cone-bone interface with 3mm of subsidence compared to 6-week films. How would you manage this patient?"

EXCEPTIONAL ANSWER

This presentation is concerning for aseptic loosening of the tibial cone construct with radiographic evidence of progressive lucency and subsidence indicating failure of osseointegration. My management approach would be systematic: First, confirm aseptic loosening vs infection - check inflammatory markers (ESR, CRP), perform knee aspiration with cell count, differential, and cultures (WBC greater than 3000, PMN greater than 80% suggests infection). Second, if infection ruled out, assess symptoms - progressive pain with weight-bearing, functional limitation, mechanical symptoms vs mild pain with high activity level. Third, radiographic assessment of component stability - serial radiographs to document progression (subsidence greater than 5mm or progressive lucencies greater than 2mm indicate failure), assess stem integrity and femoral component. Fourth, management decision tree: (a) If symptomatic with progressive radiographic loosening (subsidence increasing, lucencies widening), revision surgery indicated; (b) If asymptomatic or mild symptoms with stable radiographs (no further subsidence, lucencies non-progressive), close observation with 3-month radiographic surveillance; (c) For revision cases, intraoperative options include larger cone if adequate bone stock remains, structural allograft or custom implant if massive bone loss (AORI 3), or hinged prosthesis if associated instability. The critical decision factors are symptom severity, radiographic progression, and infection status - a 2mm lucency with 3mm subsidence at 1 year likely represents early failure requiring revision, especially if symptomatic.

TKA Revision - Tibial Cone - Exam Day Summary

High-Yield Exam Summary

References

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. PMID: 18977638. Seminal study demonstrating 80% osseointegration at 2 years, establishes biological fixation principles for tibial cones.
Howard JL, Kudera J, Lewallen DG, Hanssen AD. Early results of the use of tantalum femoral cones for revision total knee arthroplasty. J Bone Joint Surg Am. 2011;93(5):478-484. PMID: 21368080. Mayo Clinic series showing 75% survivorship at mean 3.5 years, identifies press-fit stability as critical success factor.
Kamath AF, Lewallen DG, Hanssen AD. Porous tantalum metaphyseal cones for severe tibial bone loss in revision knee arthroplasty: a five to nine-year follow-up. J Bone Joint Surg Am. 2015;97(3):216-223. PMID: 25653321. Long-term outcomes demonstrating 80% survivorship at mean 7.4 years, confirms durability of cone constructs.
Derome P, Sternheim A, Backstein D, Malo M. Treatment of large bone defects with trabecular metal cones in revision total knee arthroplasty: short term clinical and radiographic outcomes. J Arthroplasty. 2014;29(1):122-126. PMID: 23768916. Demonstrates 3mm mean subsidence at 2 years, establishes radiographic surveillance criteria for failure.
Lachiewicz PF, Bolognesi MP, Henderson RA, Soileau ES, Vail TP. Can tantalum cones provide fixation in complex revision knee arthroplasty? Clin Orthop Relat Res. 2012;470(1):199-204. PMID: 21656316. Examines fixation principles, shows 60-70% surface contact minimum required for osseointegration.
Meneghini RM, Lewallen DG, Hanssen AD. Use of porous tantalum metaphyseal cones for severe tibial bone loss during revision total knee replacement. J Bone Joint Surg Am. 2008;90(1):78-84. PMID: 18171960. Establishes AORI Type 2B/3 as primary indications, compares outcomes to augment-only reconstruction.
De Martino I, De Santis V, Sculco PK, D'Apolito R, Assini JB, Gasparini G. Tantalum cones provide durable fixation for tibial defects in primary total knee arthroplasty. Clin Orthop Relat Res. 2015;473(10):3176-3185. PMID: 26040965. Extends cone use to primary TKA with bone loss, reports 95% survivorship at 5 years in selected cases.
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: 10098040. Classic reference for AORI classification system, guides defect assessment and reconstruction strategy.
Radnay CS, Scuderi GR. Management of bone loss: augments, cones, offset stems. Clin Orthop Relat Res. 2006;446:83-92. PMID: 16672876. Compares reconstruction options, establishes algorithm for cone vs augment vs allograft selection.
Beckmann NA, Mueller S, Gondan M, Jaeger S, Reiner T, Bitsch RG. Treatment of severe bone defects during revision total knee arthroplasty with structural allografts and porous metal cones - a systematic review. J Arthroplasty. 2015;30(2):249-253. PMID: 25311761. Systematic review comparing cones (75-80% survivorship) to structural allograft (40-50%), supports cone preference for AORI 2B/3.

TKA Revision - Tibial Component with Cones