High-yield overview
Medial parapatellar arthrotomy through the previous scar, with extensile exposure on demand (quadriceps snip, V-Y turndown, tibial tubercle osteotomy) | Advanced
Adult reconstructionSubspecialty
AORI 2B–3Typical defect revised
5 danger zonesAround the proximal tibia
90–150 minTypical duration
Critical Must-Knows
- A failed primary TKR needs tibial revision for aseptic loosening (often AORI Type 2B–3), osteolysis, subsidence, polyethylene wear, or infection (as a staged revision). Always aspirate first — 10–15 percent of presumed aseptic failures are culture-positive.
- Classify the tibial bone defect with the AORI system only AFTER all cement is removed — the true defect is otherwise hidden. Type 1 intact, 2A rim intact, 2B one-condyle rim deficient, 3 both condyles deficient.
- Match reconstruction to the defect: augments or cement for 2A, a tantalum cone or metaphyseal sleeve for 2B–3. Tantalum cones have largely replaced structural allograft (greater than 95 percent survival at 5 years).
- Choose the LEAST constraint that stabilises the knee — PCR, PS, CCK, rotating hinge, fixed hinge — and move UP the ladder if in doubt; an underconstrained revision fails early from instability.
- Achieve fixation in two of the three tibial zones (epiphysis, metaphysis, diaphysis) — the Morgan-Jones principle. A long stem (100–150 mm) bypasses the defect by two cortical diameters; hybrid fixation (press-fit stem, cemented baseplate) is the workhorse.
When & Why
Indications. Tibial component revision is undertaken for aseptic loosening (radiolucent lines greater than 2 mm or progressive on serial films), symptomatic polyethylene wear with osteolysis, a malpositioned component causing instability or accelerated wear, periprosthetic infection (as a staged revision), periprosthetic fracture with a loose component, and instability that cannot be corrected by a polyethylene exchange alone. The threshold to remove a tibial component at revision is low — the single best time to address it is now. Settle three questions before surgery. The whole operation is shaped by the answers:
Is it infected?
Aspirate every revision knee — 10–15 percent of presumed aseptic failures are culture-positive. Bloods (CRP, ESR, FBC) and aspiration for cell count, differential, Gram stain, culture and crystals.
How much bone is lost?
Weight-bearing AP, lateral and skyline films, plus a CT to map the tibial defect and the canal. Defects are then classified with the AORI system — but only after all cement is out at surgery.
Are the ligaments competent?
The integrity of the PCL and the collaterals sets the constraint — PCR, PS, CCK, rotating hinge or fixed hinge. Choose the least constraint that stabilises the knee.
The constraint ladder — the headline decision. Constraint is chosen from the ligament competence and the bone loss, and you move UP it whenever the knee is not stable:
PCR (posterior cruciate retaining)
- When
- PCL intact and flexion-extension gaps balanced
- Notes
- Rare in revision — single-component exchange with intact soft tissues
PS (posterior stabilized)
- When
- PCL deficient or sacrificed, ligaments otherwise intact
- Notes
- Most common constraint for isolated tibial revision
CCK (constrained condylar knee)
- When
- MCL or LCL incompetent (more than 5 mm laxity)
- Notes
- Taller polyethylene post (15–20 mm), large femoral cam, stems on both components
RHK (rotating hinge knee)
- When
- Global ligament insufficiency or major bone loss
- Notes
- Linked; allows flexion-extension plus axial rotation, lowering interface stress
Fixed hinge
- When
- Massive bone loss preventing rotation; tumour reconstruction
- Notes
- Highest constraint and highest interface stress
Consent specifically for the higher infection risk of revision (5–10 percent versus 1–2 percent in primary), blood loss and transfusion, stiffness or residual instability, periprosthetic fracture, extensor mechanism problems, and the possibility of finding infection and converting to a staged procedure on the table. Setup. Supine with a foot bolster, thigh-high tourniquet, image intensifier available. The knee must flex freely past 90 degrees. Headlight and loupe magnification help cement removal and defect assessment.
The Operation
The goal is a stable, well-aligned, well-fixed tibial component that bypasses the bone defect, restores the joint line, and balances the knee — achieved by removing the old construct while preserving bone stock, classifying the true defect, reconstructing it, and selecting the right stem and constraint. The exposure is the first and most important part of the case: in a stiff, scarred revision knee a safe exposure protects the extensor mechanism and prevents the catastrophes.
Extensile exposure ladder. Start with the standard medial parapatellar arthrotomy; escalate only as much as the knee demands. The quadriceps snip is the safe first step; the tibial tubercle osteotomy gives the most exposure but the most morbidity.
Quadriceps snip (first line)
- When and how
- A 45-degree oblique incision from the proximal VMO into the quadriceps tendon; adds 2–3 cm of exposure
- The price
- Minimal morbidity and heals reliably; usually adequate
V-Y quadriceps turndown (Coonse-Adams)
- When and how
- An inverted V in the quadriceps tendon, the flap turned distally over the patella
- The price
- Big exposure gain but delays rehabilitation (protected ROM 6 weeks) and risks extensor lag
Tibial tubercle osteotomy (TTO)
- When and how
- 8–12 cm long, 2 cm wide, 1 cm deep, lateral hinge preserved; fix with screws or cables
- The price
- Best exposure but highest morbidity — increased infection risk and 2 percent nonunion
Rectus snip (Garvin)
- When and how
- A transverse cut through the rectus femoris proximal to the patella
- The price
- Less commonly used
Operative sequence
Step 1Exposure and arthrotomy
- Use the most lateral viable skin scar to reduce wound complications and raise full-thickness fasciocutaneous flaps.
- Medial parapatellar arthrotomy extending 5–6 cm above the patella into the quadriceps tendon; excise hypertrophic synovium and scar.
- Document extensor mechanism integrity and any pre-operative extensor lag.
- In a stiff knee, release the patella from the lateral gutter before attempting eversion; add a quadriceps snip if it will not evert safely. Preserve the patellar tendon insertion — avulsion is catastrophic.
Step 2Remove the polyethylene insert
- Remove the insert first with a curved osteotome or dedicated extraction tool, flexing the knee to 90 degrees to deliver it anteriorly.
- Inspect the backside for wear, delamination and locking-mechanism failure; document the wear pattern — asymmetric wear suggests instability or malalignment.
- Send the explant for analysis and photograph the components; take periprosthetic tissue for frozen section if infection is suspected.
Step 3Assess tibial baseplate fixation
- Test baseplate stability with a curved osteotome around the periphery, checking for micromotion and subsidence against the radiographs.
- If loose, proceed to extraction. If well-fixed and well-positioned it may be retained, but the threshold for removal is low at revision.
- Revise a well-fixed component when it is malaligned more than 3 degrees varus or valgus, internally rotated more than 10 degrees, has posterior-slope error more than 5 degrees, has subsided more than 2 mm, when osteolysis needs access, or when more constraint or a stem is required.
Step 4Remove the tibial baseplate
- Disrupt the cement-bone interface circumferentially with flexible osteotomes, working anterior to posterior.
- Use a slap hammer and tibial extractor, or Gigli saws passed beneath the baseplate; avoid excessive force and extract in flexion with a gentle rocking motion.
- For cementless ingrown components Gigli saws are safer than osteotomes; ultrasonic cement removal (UCS) is faster and more bone-sparing for cemented components. Preserve bone stock — this is the critical step and takes 15–30 minutes; do not rush.
Step 5Cement removal and debridement
- Remove all cement and fibrous membrane down to bleeding bone with narrow osteotomes, curettes, a high-speed burr and ultrasonic tools (Midas Rex), working anterior to posterior.
- Preserve the cortical shell and metaphyseal stock; irrigate constantly to limit thermal injury; finish with pulsatile lavage.
- Take at least five tissue samples for culture even in an aseptic revision; consider vancomycin powder before closure.
Step 6Assess the bone defect (AORI)
- Classify tibial defects with the AORI system now that all cement is out — Type 1 intact, 2A damaged with rim intact, 2B rim deficient on one condyle, 3 rim deficient on both condyles.
- Map each defect for anteroposterior depth and mediolateral width; distinguish contained from uncontained defects.
- Palpate the posterior and posteromedial tibia — posterior defects are common and easily underestimated.
Step 7Prepare the canal for the stem
- Ream with flexible reamers starting 1–2 mm larger than the canal, advancing to cortical chatter in 1 mm increments.
- Ream line-to-line for a press-fit stem; over-ream 2 mm for a cemented stem to leave a cement mantle.
- Aim for 4–6 cm of diaphyseal contact with a short stem and 10–15 cm with a long stem. Watch for the anterior and lateral tibial bow — anterior and lateral cortical perforation are the dangers.
Step 8Prepare the proximal tibia
- Use intramedullary alignment referenced off the stem trial; set posterior slope to 3–7 degrees (match the pre-operative slope, increase it if the PCL is deficient) and varus/valgus to neutral.
- Resect the minimum bone needed — typically 2–4 mm more than a primary cut — to reach a flat, bleeding surface.
- Reference off the most intact plateau (often the lateral side in a failed varus knee); the target is a medial proximal tibial angle of about 90 degrees. Preserve the peripheral cortical rim wherever possible.
Step 9Reconstruct the defect
- Type 2A — screws and cement or small modular augments (5–10 mm) for contained defects under 5 mm.
- Type 2B — metal augments (blocks or wedges) on the deficient side, or a tantalum cone.
- Type 3 — large cones, metaphyseal sleeves, or structural allograft.
- Augments must be fully supported by host bone and screw-fixed where possible; the baseplate is cemented INTO a cone or sleeve to achieve biological metaphyseal fixation.
Step 10Trial reduction and gap balance
- Assemble the trial baseplate, stem, augments or cone with the femoral trial and a trial polyethylene.
- Reduce through a full arc and check stability (no lift-off), neutral alignment, central patellar tracking and flexion-extension gap balance (equal within 2 mm), targeting 0–120 degrees.
- Stress in extension and at 30 degrees — no more than 5 mm opening is acceptable. Move up the constraint ladder if the MCL is incompetent (more than 5 mm laxity → CCK) or instability is global (rotating hinge or fixed hinge).
Step 11Prepare for final implantation
- Clean and dry the bone with pulsatile lavage and suction.
- Use high-viscosity cement with third-generation technique (clean dry bone, cement gun, pressurisation, insertion in the doughy phase). For hybrid fixation insert the press-fit stem first, then cement the baseplate to stem and bone.
- Consider low-dose antibiotic-loaded cement even in an aseptic revision (roughly 1 g vancomycin plus 1 g tobramycin or gentamicin per 40 g, keeping the additive load low so structural cement keeps its strength). Remove excess cement before it polymerises.
Step 12Insert the tibial component
- Insert the stem first (hybrid), apply cement to the tibial surface and the baseplate undersurface, seat the baseplate and impact gently.
- Set rotation to the medial third of the tibial tubercle (Insall) or the Akagi line (medial border of the patellar tendon to the centre of the PCL footprint); in revision, the safest reference is to match the baseplate to the femoral component through a balanced flexion gap.
- Confirm AP position — cover the maximal tibial surface without overhang (anterior overhang irritates the patellar tendon; posterior overhang threatens the neurovascular bundle). Avoid the common error of internal rotation, which drives lateral tracking, anterior knee pain and medial polyethylene wear.
Step 13Insert the polyethylene and reduce
- Clean and dry the baseplate locking mechanism meticulously, insert the polyethylene and confirm the lock — an audible click and a positive traction test.
- Reduce the knee and assess final stability, range of motion and patellar tracking.
- Poly thickness gives stability without overstuffing: minimum 10 mm for PS, 12–15 mm for CCK (taller post), 15–20 mm for hinges. Target no varus/valgus laxity more than 5 mm at 0 or 30 degrees, no AP laxity more than 5 mm at 90 degrees, and 0–120 degrees of motion.
Step 14Final assessment and closure
- Confirm 0–120 degrees, a stable arc, central tracking and no impingement; remove all loose cement and debris with 6–9 L of lavage.
- Meticulous hemostasis, a deep drain, then close the capsule and extensor mechanism in flexion with interrupted figure-of-8 sutures (No. 2 Ethibond); close subcutaneous layers and skin.
- Tranexamic acid 1 g IV at induction and 1 g at closure reduces blood loss by about 40 percent. If a TTO was performed, protect the extensor mechanism with an extended-knee brace for 24 hours.
Step 15Post-operative protocol
- Elevate and ice the leg; continue IV antibiotics 24–48 hours and use mechanical plus risk-stratified pharmacological VTE prophylaxis (extended duration after revision per local, NICE or AAOS pathways).
- Quadriceps isometrics and ankle pumps immediately; mobilise on day 1 — weight-bearing as tolerated for cemented or hybrid constructs, protected for press-fit.
- Remove the drain at 24–48 hours. Expect CRP to peak at day 2–3 and normalise by 3–4 weeks and ESR to peak at week 1 and normalise by 6–8 weeks; persistent elevation warrants investigation for infection.
Critical danger structures. Five structures around the proximal tibia account for nearly all serious morbidity:
Popliteal artery
- Where it lies
- Posterior to the tibia in the popliteal fossa, 1–2 cm from the posterior tibial cortex in flexion
- How to protect it
- Flex the knee for posterior work, place Hohmann retractors carefully and palpate before any posterior resection
Common peroneal nerve
- Where it lies
- Winds around the fibular neck, 2–3 cm distal to the fibular head
- How to protect it
- Avoid correcting valgus more than 10 degrees at once, protect lateral structures, release the tourniquet before closure to check vascularity
Patellar tendon
- Where it lies
- Inserts on the tibial tubercle; at risk during exposure and extensile approaches
- How to protect it
- Evert gently, use a TTO (8–12 cm) when needed, protect the insertion throughout
Medial collateral ligament
- Where it lies
- Superficial MCL attaches to the medial tibial metaphysis about 6 cm below the joint, deep to pes anserinus
- How to protect it
- Preserve it during tibial preparation; subperiosteal dissection only if exposure demands
Tibial cortex
- Where it lies
- Thin anterior and medial cortex, worse with osteopenia or osteolysis
- How to protect it
- Avoid eccentric reaming, use the intramedullary guide carefully, stop at cortical chatter, watch for stress risers
Patellar tendon avulsion — the catastrophe
Forced eversion of a stiff knee avulses the patellar tendon from the tubercle and is disabling. Prevent it: release the patella from the lateral gutter first, add a quadriceps snip, and move to a tibial tubercle osteotomy if the tendon is still under tension. Never lever against the tendon.
Classify the defect only after all cement is out
AORI classification is meaningless while cement and fibrous membrane remain — they mask the true cavitary and segmental loss. Remove all cement and debride to bleeding bone, then palpate the posterior tibial plateau (underestimated on imaging) before you grade the defect and choose the reconstruction.
Move up the constraint ladder if in doubt
Underconstraint fails early from instability. If the trial lifts off in extension or at 30 degrees, or the MCL is incompetent with more than 5 mm laxity, move up — PS to CCK to rotating hinge to fixed hinge. Stems are mandatory once you leave the PS level to protect the constrained interface.
Aftercare & Complications
Rehabilitation | Phase | Timing | Milestones | |-------|--------|------------| | Immediate | Days 0–3 | Elevation, ice, compression; IV antibiotics 24–48 h; mechanical plus risk-stratified VTE prophylaxis; drain out by 24–48 h; quad isometrics, ankle pumps, SLR; mobilise day 1 WBAT for cemented or hybrid | | Early | Weeks 1–6 | Wound check at 2 weeks; radiographs at 6 weeks; ROM goal 90 degrees by 2 weeks and 120 degrees by 6 weeks; single crutch by 4–6 weeks | | Intermediate | Weeks 6–12 | Full weight-bearing without aids; stairs and transfers; driving at 6–8 weeks (automatic or left knee) or 8–12 weeks (right knee); sedentary work 6–8 weeks, manual 12 weeks or more | | Long-term | 3 months onward | Annual radiographs; avoid high-impact sports; report pain, swelling or drainage promptly | Routine antibiotic prophylaxis for dental procedures is NOT recommended for most arthroplasty patients (AAOS and ADA guidance); reserve it for individually assessed high-risk patients. Complications
Infection (5–10 percent)
- Recognition
- Pain, warmth, swelling, drainage, elevated CRP/ESR, positive aspiration (WCC more than 3000, PMN more than 80 percent)
- Prevention
- Antibiotic cement, prophylactic IV antibiotics, laminar flow, meticulous hemostasis and tissue handling
- Management
- Acute (under 3 weeks): DAIR with poly exchange. Chronic: two-stage revision with an antibiotic spacer for 6–12 weeks and culture-directed IV antibiotics for at least 6 weeks
Aseptic loosening
- Recognition
- Progressive pain, radiolucent lines more than 2 mm on serial films, component migration or subsidence
- Prevention
- Adequate bone preparation, appropriate fixation, correct alignment and reconstruction of defects
- Management
- Re-revision with larger stems and cones or sleeves; reassess for infection (10–15 percent of aseptic failures are culture-positive)
Instability
- Recognition
- Give-way, effusion, abnormal laxity, dissatisfaction, accelerated wear
- Prevention
- Appropriate constraint selection, gap balancing, ligament tensioning and correct alignment
- Management
- Revise to higher constraint (CCK to RHK to hinge), correct alignment, soft-tissue reconstruction where possible
Periprosthetic fracture
- Recognition
- Acute pain, unable to weight-bear, deformity, intra-operative crack
- Prevention
- Gentle technique, avoid cortical perforation, appropriate stem length, assess bone quality pre-operatively
- Management
- Stable component: ORIF. Unstable: revision with a long stem bypassing the fracture by two cortical diameters; the Felix classification guides management
Extensor mechanism failure
- Recognition
- Extensor lag, unable to actively extend, palpable gap, patella alta or baja
- Prevention
- Protect the patellar tendon, careful TTO fixation (8–12 cm), avoid overstuffing
- Management
- Acute: primary repair. Chronic: allograft reconstruction (Achilles, extensor mechanism allograft). Patella baja: TTO advancement
Stiffness (under 90 degrees flexion)
- Recognition
- Limited ROM, dissatisfaction, difficulty with stairs or sitting, arthrofibrosis
- Prevention
- Early ROM and CPM, adequate analgesia, avoid overstuffing, correct component position
- Management
- MUA within 12 weeks; later, arthroscopic or open arthrolysis; address component malposition if identified
Viva & Exam Focus
Mnemonic
REVISEREVISE — the revision tibial workflow
R
Radiographs, CT — and aspirate first
Exclude occult infection (10–15 percent of presumed aseptic failures are culture-positive) and map the bone loss
E
Exposure via the most lateral scar
Medial parapatellar arthrotomy; escalate with a quadriceps snip if the knee is stiff
V
Verify the true defect — classify AORI
Only after ALL cement is removed; palpate the posterior plateau
I
Implant — least constraint that stabilises
PCR to PS to CCK to rotating hinge to fixed hinge; underconstraint fails early
S
Stem fixation in 2 of 3 zones
Stem bypasses the defect by two cortical diameters; hybrid is the workhorse
E
Ensure rotation and gap balance
Match the baseplate to the femur through a balanced flexion gap; gaps equal within 2 mm
Mnemonic
STEPUPSTEPUP — the constraint ladder
S
Stable knee, PCL intact
PCR — rare in revision, single-component exchange
T
Torn or deficient PCL
PS (posterior stabilized) — the most common isolated tibial revision
E
Edge (coronal) instability
MCL incompetent, more than 5 mm laxity — CCK with a taller post and stems
P
Pan-ligamentous, global instability
RHK (rotating hinge) — linked, allows rotation to lower interface stress
U
Unreconstructable bone loss
Fixed hinge or megaprosthesis — tumour territory, highest interface stress
P
Principle — move UP the ladder
Increase constraint whenever the knee is not stable; an underconstrained TKR fails early
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
Viva scenarioStandard
Clinical prompt
“You are shown radiographs of a painful TKR 8 years after the primary, with radiolucent lines around the tibial component and subsidence. How would you assess and manage this patient?”
Viva scenarioStandard
Clinical prompt
“Describe your approach to tibial component revision for aseptic loosening with an AORI Type 2B bone loss affecting the medial tibial plateau.”
Viva scenarioStandard
Clinical prompt
“During tibial component revision you find the component grossly loose with significant bone loss and discover purulent material in the joint despite a negative pre-operative aspiration. How do you proceed?”
Exam day cheat sheet
Revision TKR — tibial component — exam essentials
Key indications
- Aseptic loosening with radiolucent lines more than 2 mm or progressive
- Polyethylene wear with osteolysis
- Component malalignment causing instability or wear
- Periprosthetic infection (staged revision)
- Periprosthetic fracture with a loose component
- Instability not manageable with a poly exchange
AORI classification
- Type 1: intact metaphysis — standard components
- Type 2A: damaged metaphysis, intact rim — augments or cement
- Type 2B: rim deficient on ONE condyle — cone or sleeve
- Type 3: rim deficient on BOTH condyles — major reconstruction
- Classify AFTER cement removal for the true defect
Constraint ladder
- PCR then PS then CCK then RHK then fixed hinge
- Move UP the ladder with ligament deficiency
- PS: most common for a standard revision
- CCK: MCL incompetence (more than 5 mm laxity)
- RHK: global instability or massive bone loss
Stem principles
- Short (50–75 mm): AORI 1–2A, rotational control
- Long (100–150 mm): AORI 2B–3, bypass defect by two cortical diameters
- Press-fit: better long-term biological fixation
- Hybrid: press-fit stem plus cemented baseplate (the workhorse)
- Offset stems for canal deformity
- Zonal fixation (Morgan-Jones): secure 2 of 3 zones — epiphysis, metaphysis, diaphysis
Defect reconstruction
- Cement plus screws: small contained defects under 5 mm
- Metal augments: 5–15 mm defects with an intact rim
- Tantalum cones: AORI 2B–3, press-fit, biological fixation
- Metaphyseal sleeves: severe metaphyseal loss
- Structural allograft: last resort (resorption risk)
Critical steps
- Most lateral skin scar, full-thickness flaps
- Extensile exposure if needed (quad snip then V-Y then TTO)
- ALWAYS aspirate pre-operatively — 10–15 percent occult PJI
- Send at least five intra-operative tissue samples
- Remove ALL cement before classifying defects
- Antibiotic cement even in an aseptic revision
Danger zones
- Popliteal artery: 1–2 cm posterior in flexion
- Common peroneal nerve: lateral fibular neck
- Patellar tendon: protect the insertion at all costs
- MCL: subperiosteal dissection if exposure needed
- Tibial cortex: avoid eccentric reaming
Numbers to know
- Infection rate: 5–10 percent revision versus 1–2 percent primary
- Aspiration: WCC more than 3000 and PMN more than 80 percent equals infection
- Radiolucent lines: more than 2 mm equals loosening
- Tibial slope: 3–7 degrees posterior
- Gap balance: flexion and extension equal within 2 mm
- VTE prophylaxis: risk-stratified, extended duration after revision
Background & Evidence
Why revision is harder. National registries (the NJR for England, Wales and Northern Ireland, AJRR in the US, AOANJRR in Australia, SHAR in Sweden and the NZJR) consistently report aseptic loosening, infection and instability as the leading indications for knee revision, and document inferior cumulative survivorship of revision compared with primary TKA. That registry evidence underpins both the higher quoted complication and re-revision rates after revision surgery and the modern push for constructs that achieve fixation in two of the three tibial zones. AORI bone defect classification (Engh and Ammeen). The classification is made on the true defect seen at surgery:
1
- Defect
- Intact metaphysis — minor cancellous defects, intact cortical rim, no subsidence
- Reconstruction
- Standard primary-sized components
2A
- Defect
- Damaged metaphysis with an intact peripheral rim; cavitary defects
- Reconstruction
- Cement fill, screws, small modular augments (5–10 mm)
2B
- Defect
- Cortical rim deficient on one condyle
- Reconstruction
- Metal augments, a tantalum cone, or a metaphyseal sleeve
3
- Defect
- Cortical rim deficient on both condyles; massive metaphyseal loss
- Reconstruction
- Large cones or sleeves on both sides, structural allograft, a hinged prosthesis or megaprosthesis
Defect reconstruction toolkit. Reconstruction is matched to the AORI type and to whether the defect is contained or uncontained:
Cement plus screws
- AORI type
- 2A, contained and under 5 mm
- Principle
- Screws into sclerotic bone first, cement fills around; not for uncontained defects
Metal augments (blocks or wedges)
- AORI type
- 2A–2B
- Principle
- 5, 10 or 15 mm; screw-fixed to host bone and cemented to the baseplate; up to 15–20 mm
Tantalum cones
- AORI type
- 2B–3
- Principle
- Press-fit into the defect with biological ingrowth, baseplate cemented into the cone; greater than 95 percent 5-year survival
Metaphyseal sleeves
- AORI type
- 2B–3
- Principle
- Press-fit into the proximal tibia with an integral stem, metaphyseal fixation, less reliance on the diaphysis
Structural allograft
- AORI type
- 3, massive
- Principle
- Femoral head or tibial plateau; risk of resorption and collapse; 70–80 percent 10-year survival; reserve when cones or sleeves will not do
Press-fit (cementless)
- Best for
- Good diaphyseal bone
- Key points
- 2-degree tapered stem with 3-point fixation, line-to-line reaming, biological ingrowth, best long-term survivorship; restrict weight-bearing for 6 weeks
Cemented
- Best for
- Poor bone quality or elderly
- Key points
- Over-ream 2 mm for a cement mantle, third-generation technique, immediate weight-bearing; watch for posterior cement extrusion
Hybrid (workhorse)
- Best for
- Most revisions
- Key points
- Press-fit stem into the diaphysis plus a cemented baseplate; immediate weight-bearing with biological diaphyseal fixation
Offset stems
- Best for
- Canal deformity or malunion
- Key points
- 2–4 mm offset; curved stems available for the anterior tibial bow
- VTE prophylaxis: NICE recommends extended pharmacological prophylaxis after knee arthroplasty; AAOS and ACCP accept aspirin or a DOAC or LMWH in standard-risk patients, with extended duration commonly applied after revision. Always risk-stratify and combine with mechanical prophylaxis.
- Dental antibiotic prophylaxis: AAOS and ADA no longer recommend routine prophylaxis for dental procedures in most arthroplasty patients; reserve it for individually assessed high-risk cases.
- Periprosthetic joint infection thresholds follow international consensus (ICM and EBJIS) criteria rather than any single national standard.
- Surgical exposures for revision are reviewed in depth by Della Valle, Berger and Rosenberg (Clin Orthop Relat Res 2006;446:59–68).
References
Evidence
Use of porous tantalum metaphyseal cones for severe tibial bone loss during revision total knee replacement
Meneghini RM, Lewallen DG, Hanssen AD • J Bone Joint Surg Am (2008)
Key Findings:
- 15 revision TKRs (AORI Type 2B and Type 3 tibial defects) reconstructed with porous tantalum metaphyseal cones; patients had averaged 3.5 prior knee replacements
- At a mean of 34 months all 15 cones showed radiographic osseointegration with reactive trabeculation and no loosening or migration
- Mean Knee Society clinical score improved from 52 to 85 points
Clinical implication: Established porous tantalum cones as a reliable biological alternative to structural allograft for severe metaphyseal tibial bone loss, with the baseplate cemented into an osseointegrated cone.
Evidence
Clinical survivorship of aseptic revision TKA using hinged knees and tantalum cones at minimum 10-year follow-up
Abdelaziz H, Jaramillo R, Gehrke T, Ohlmeier M, Citak M • J Arthroplasty (2019)
Key Findings:
- 32 tantalum cones in 25 hinged-knee revisions followed for a minimum of 10 years (mean 126 months)
- 24 of 32 cones (75 percent) survived without exchange; aseptic loosening accounted for 5 of 8 cone revisions, four of which were in pure (non-rotating) hinge constructs
- Authors recommend rotating-hinge rather than pure-hinge designs to reduce interface stress and aseptic loosening
Clinical implication: Confirms durable but not infallible long-term cone fixation, and supports using a rotating hinge (not a fixed or pure hinge) when maximal constraint is required, to lower aseptic loosening risk.
Evidence
Zonal fixation in revision total knee arthroplasty
Morgan-Jones R, Oussedik SIS, Graichen H, Haddad FS • Bone Joint J (2015)
Key Findings:
- Defines three fixation zones in the tibia and femur: epiphysis (joint surface), metaphysis and diaphysis
- Recommends achieving solid fixation in at least two of the three zones for a stable revision construct
- Emphasises pre-operative planning and implant selection to match the bone loss pattern
Clinical implication: Provides the modern conceptual framework for revision tibial fixation: combine cemented epiphyseal or baseplate fixation, a metaphyseal cone or sleeve, and a diaphyseal-engaging stem to secure at least two zones.
Evidence
Bone loss with revision total knee arthroplasty: defect classification and alternatives for reconstruction
Engh GA, Ammeen DJ • Instr Course Lect (1999)
Key Findings:
- Describes the Anderson Orthopaedic Research Institute (AORI) classification of femoral and tibial bone defects (Types 1, 2A, 2B, 3)
- Outlines the four reconstruction variables: implant constraint, stem configuration, stem fixation and method of defect repair
- Recommends selecting the least constraint needed for stability and matching stem length to severity of bone loss
Clinical implication: The foundational classification and decision framework for revision knee bone-defect management, still used to plan augments, cones, sleeves, allograft and constraint level.
Evidence
Ten-year survival and clinical results of constrained components in primary total knee arthroplasty
Lachiewicz PF, Soileau ES • J Arthroplasty (2006)
Key Findings:
- Prospective series of 54 constrained condylar (CCK) knees implanted for incompetent MCL, fixed valgus or severe flexion contracture
- Ten-year survival with revision for loosening as the endpoint was 96 percent (95 percent CI 90.6 to 100) with 86 percent good or excellent results
- Only two revisions for loosening occurred across the cohort
Clinical implication: Demonstrates that constrained condylar articulations are durable when coronal instability cannot be balanced, supporting their use on the revision constraint ladder when the MCL is incompetent; stemmed fixation is required to protect the constrained interface.