High-yield overview
The workhorse controlled femoral osteotomy for implant and cement removal in revision hip arthroplasty
12-15 cmTypical osteotomy length from tip of greater trochanter
One thirdProportion of femoral circumference in the osteotomised fragment
4-6 cmMinimum diaphyseal fixation required distal to the osteotomy for the revision stem
Greater than 90-95 percentReported union rates with a vascularised fragment and cable fixation
Critical Must-Knows
- Core principle: the lateral third of the proximal femur is elevated as a vascularised osteomuscular sleeve with the vastus lateralis and abductors left attached — this vascularity drives the high union rate
- Indications: removal of well-fixed cementless or cemented stems, distal cement extraction, varus proximal femoral remodelling, exposure in periprosthetic infection, and improved acetabular exposure
- Length is templated preoperatively: distal enough to clear the stem tip or cement column, but leaving at least 4-6 cm of intact diaphysis for fixation of the revision stem
- A prophylactic distal cerclage cable placed 1-2 cm below the transverse limb BEFORE reaming and stem insertion prevents distal crack propagation — the single most examinable technical step
- Revision stems must bypass the osteotomy and achieve diaphyseal fixation: modular fluted tapered titanium or extensively porous-coated cobalt-chrome stems; proximally coated stems are contraindicated
- Complications: fragment migration/trochanteric escape, non-union (usually fibrous and often asymptomatic), fracture propagation, abductor weakness, cable-related trochanteric bursitis
Clinical Pearls
- “The anterior hinge is created by controlled anterior perforations and gentle osteotome levering — an uncontrolled hinge fracture converts a planned osteotomy into an unplanned periprosthetic fracture
- “In infection, ETO is safe and does not compromise two-stage exchange; it dramatically speeds removal of well-fixed implants and cement, reducing cortical perforation and operative time
- “Wagner described a straight lateral transfemoral approach; the Paprosky/Younger posterior-based ETO is the technique most commonly described in modern revision practice
Highest-Stakes Points
Preserve the Soft Tissue Sleeve
The vastus lateralis and gluteus medius/minimus must remain attached to the fragment throughout. Stripping the fragment devascularises it and converts a greater than 95 percent union rate into a non-union and escape problem.
Prophylactic Distal Cerclage
Place a cerclage cable or wire 1-2 cm distal to the transverse limb before reaming, trialling or impacting the revision stem. Hoop stresses during insertion otherwise propagate a longitudinal crack distally and destroy the fixation zone.
Stem Choice Is Non-Negotiable
The proximal femur cannot support a stem after ETO. Use a stem gaining 4-6 cm of scratch-fit diaphyseal fixation distal to the osteotomy — modular fluted tapered or extensively porous-coated. Cemented or proximally coated primary stems will subside and fail.
Controlled Anterior Hinge
The anterior cortex is perforated with a drill or pencil-tip burr and levered open with wide osteotomes in unison along the length. Cracking it open at a single point causes an uncontrolled fracture of the fragment or anterior cortex.
Rationale and Indications
The ETO converts a hostile femoral revision into a controlled, reproducible exposure. Rather than fighting a well-fixed stem or distal cement mantle from above — risking cortical perforation, eccentric reaming and greater trochanteric fracture — the surgeon opens the lateral femur like the lid of a box, works on the implant-bone or cement-bone interfaces under direct vision, then closes and cables the lid.
Indications
- Removal of a well-fixed cementless stem — especially extensively porous-coated stems, where the distal interface cannot be reached from the shoulder of the implant
- Removal of a well-fixed cemented stem and distal cement column — direct access to the cement mantle avoids perforation and cortical windows
- Varus proximal femoral remodelling — a loose stem remodels the proximal femur into varus; straight-line reaming from above would perforate the lateral cortex, whereas ETO allows neutral alignment of the new stem
- Periprosthetic joint infection — rapid, complete removal of implants and cement at first-stage exchange; retained cement is a common cause of persistent infection
- Exposure — improved acetabular access in stiff or protrusio hips, and safe dislocation of a stiff arthroplasty where forced dislocation risks femoral fracture
- Selected Vancouver B2/B3 periprosthetic fractures — the fracture may be incorporated into the osteotomy
Relative contraindications
- Severely osteoporotic or ectatic bone where the fragment will fragment further (consider cortical struts or endoprosthetic replacement)
- Inadequate intact diaphysis distal to the planned osteotomy (less than 4 cm of supportive isthmus — Paprosky IIIB/IV femora may need impaction grafting, a cemented long stem or a proximal femoral replacement)
Preoperative Planning
- Full-length AP and lateral femoral radiographs including the entire stem and cement column
- Mark the tip of the greater trochanter as the proximal reference
- The osteotomy must extend distal to the stem tip and any distal cement plug so the interfaces can be accessed under vision; typical length 12-15 cm from the tip of the greater trochanter
- Then confirm that at least 4-6 cm of intact, supportive diaphysis remains between the transverse limb and the point where the canal flares or bone quality deteriorates — this is the fixation zone for the revision stem
- Template the revision stem: it should engage the isthmus with a scratch fit over 4-6 cm; if the templated stem cannot achieve this, reconsider the reconstruction (longer stem, struts, or megaprosthesis)
- In varus remodelling, plan the transverse limb distal to the apex of the varus deformity so reaming re-establishes a neutral axis
Wagner versus Paprosky (Posterior-Based) ETO
Surgical approach
- Wagner transfemoral osteotomy
- Direct lateral / transgluteal
- Paprosky/Younger posterior-based ETO
- Posterior (posterolateral)
Longitudinal limb
- Wagner transfemoral osteotomy
- Anterolateral femur
- Paprosky/Younger posterior-based ETO
- Posterolateral, just anterior to linea aspera
Hinge
- Wagner transfemoral osteotomy
- Posterior soft tissue hinge
- Paprosky/Younger posterior-based ETO
- Controlled anterior bony hinge, perforated and levered open
Fragment
- Wagner transfemoral osteotomy
- Anterolateral fragment with vastus lateralis attached
- Paprosky/Younger posterior-based ETO
- Lateral one third with greater trochanter, abductors and vastus lateralis attached
Typical modern use
- Wagner transfemoral osteotomy
- Historic description; basis of the concept
- Paprosky/Younger posterior-based ETO
- Standard technique in contemporary revision practice; compatible with posterior revision exposure
Key risk
- Wagner transfemoral osteotomy
- Abductor dysfunction from lateral approach
- Paprosky/Younger posterior-based ETO
- Uncontrolled anterior hinge fracture if perforations omitted
Why posterior-based?
Most femoral revisions use a posterior approach; the posterior-based ETO flows naturally from this exposure, keeps the entire abductor-trochanter-vastus sleeve in continuity anteriorly, and hinges the fragment forward on intact anterior periosteum and perforated anterior cortex — maximising fragment vascularity.
Operative Technique (Posterior-Based ETO)
- Position: lateral decubitus on a radiolucent table, pelvis rigidly secured; check the pelvis is truly vertical (acetabular orientation errors follow pelvic malposition)
- Imaging/equipment: fluoroscopy available; full revision instrumentation checked and opened
- Approach: extended posterior approach; incise fascia lata in line with the femur; release short external rotators and posterior capsule as a flap for later repair; extend the fascial and skin incision distally along the femoral shaft to the planned osteotomy level
- Dislocate the hip posteriorly if mobile; if stiff, perform the osteotomy first and dislocate with the fragment elevated — this protects the femur from torsional fracture
Never impact the revision stem without the distal cerclage
The commonest catastrophic intraoperative error is longitudinal fracture propagation from hoop stress during broaching or stem impaction. The prophylactic cable distal to the transverse limb is cheap insurance and is expected in any viva answer on ETO technique.
ETO in the Infected Hip
- ETO is safe in periprosthetic joint infection and is often essential for complete removal of well-fixed implants and cement — retained infected cement is a recognised cause of failed two-stage exchange
- Reported union rates after ETO in staged revision for infection remain high, provided the vascular sleeve is preserved
- At first stage: cables can be retained if needed for femoral integrity; an articulating or static antibiotic spacer is placed; the osteotomy is cabled closed around the spacer
- At second stage: the healed or healing osteotomy usually does not need to be re-opened unless further debridement or cement removal is required; the definitive diaphyseal-fitting stem is inserted
- Single-stage exchange with ETO is practised in some European centres with comparable infection control in selected patients
Complications: Prevention and Management
Fragment migration / trochanteric escape
- Prevention
- Preserve soft tissue sleeve; 2-3 cables; avoid early active abduction
- Management
- If minimally symptomatic, observe; symptomatic escape — trochanteric claw/cable-grip revision fixation plus or minus bone graft
Non-union (often fibrous)
- Prevention
- Vascularised fragment, stable cable fixation, bevelled transverse limb
- Management
- Asymptomatic fibrous union — observe; painful non-union — revise fixation, graft, exclude infection
Fracture propagation distal to osteotomy
- Prevention
- Prophylactic distal cerclage BEFORE reaming/impaction; hand reaming; rounded transverse limb
- Management
- Additional cerclage; longer stem bypassing the fracture by two cortical diameters; strut allograft if comminuted
Abductor weakness / Trendelenburg gait
- Prevention
- Keep abductors attached to fragment; anatomic reduction; correct offset and length
- Management
- Abductor strengthening programme; persistent weakness with escape — reattachment/claw fixation; consider constrained or dual mobility bearing if instability
Cable-related trochanteric bursitis
- Prevention
- Sink cable crimps away from the lateral prominence; avoid cables over vastus ridge
- Management
- Analgesia, physiotherapy, image-guided injection; removal of cables once osteotomy united (usually after 6 months)
Stem subsidence
- Prevention
- Adequate scratch fit 4-6 cm; tapered stem seated to templated depth; intraoperative radiograph
- Management
- Minor early subsidence of tapered stems may self-stabilise; progressive subsidence — revise to larger/longer stem
Dislocation
- Prevention
- Restore offset, length, version; meticulous posterior repair; abduction precautions
- Management
- Closed reduction and bracing; recurrent — assess component position; dual mobility or constrained liner
Postoperative Protocol
0-6 weeksProtection phase
Protected weightbearing (touch to partial, unit-dependent) with crutches or frame. Posterior hip precautions if posterior approach. No active abduction and no abduction against resistance — the abductors pull directly on the fragment. Check radiographs before discharge and at 6 weeks.
6-12 weeksProgressive loading
If radiographs show maintained fragment position and no stem subsidence, progress to weightbearing as tolerated. Begin gentle active abduction from around 6-8 weeks once early consolidation is visible.
3-6 monthsConsolidation
Osteotomy union typically evident radiographically by 3-6 months. Abductor strengthening progresses; gait re-education for residual Trendelenburg pattern.
6-12 monthsLate review
Confirm union, stem osseointegration (spot welds, absence of subsidence or lucency). Consider cable removal only for persistent symptomatic bursitis after confirmed union.
Mnemonic
SLICEETO Planning Essentials
S
Sleeve
Vastus lateralis-abductor sleeve stays attached — vascularity is everything
L
Length
12-15 cm from trochanteric tip, beyond stem tip and cement, leaving 4-6 cm of isthmus
I
Isthmic fixation
Revision stem needs 4-6 cm scratch-fit diaphyseal fixation distal to the osteotomy
C
Cerclage first
Prophylactic distal cable before reaming and stem impaction
E
Even hinge
Perforate the anterior cortex and lever osteotomes in unison for a controlled hinge
Hook:You SLICE the lateral femur open like a lid — but only after planning the cut, the cable and the stem.
Mnemonic
CIVICIndications for ETO
C
Cement removal
Well-fixed cemented stem and distal cement column under direct vision
I
Ingrown stem
Well-fixed cementless (especially extensively coated) stem removal
V
Varus remodelling
Proximal femoral varus deformity requiring neutral realignment
I
Infection
Rapid complete implant and cement clearance at staged exchange
C
Contracted/stiff hip exposure
Facilitates dislocation and acetabular exposure without fracture
Hook:ETO serves the whole revision CIVIC duty — implant out, deformity corrected, infection cleared, exposure gained.
Guidelines, Registries & Global Practice
- Global epidemiology: revision hip arthroplasty volumes are rising worldwide with the ageing primary arthroplasty population; femoral revision for aseptic loosening, infection and periprosthetic fracture are the dominant indications in which ETO is used
- Society guidance: no society issues a stand-alone ETO guideline; the technique is embedded in revision arthroplasty teaching from AAOS, EFORT and BOA-affiliated revision networks. AO principles govern the associated periprosthetic fracture scenarios (Vancouver-based management, where B2/B3 fractures may incorporate an ETO with a diaphyseal-fitting stem). International Consensus Meeting (ICM) statements on periprosthetic joint infection support complete removal of implants and cement — the practical justification for ETO in the infected femur
- Registry evidence: national registries (NJR, AOANJRR, AJRR, SHAR, Norwegian, NZJR) capture revision stem type and survivorship rather than the osteotomy itself; they consistently show good mid-term survivorship of fluted tapered titanium revision stems, the constructs most often paired with ETO
- Practice variation by resource setting: where modular tapered systems, cable systems or ultrasonic cement removal are unavailable, surgeons rely on Wagner-type monoblock tapered stems, stainless wire cerclage and mechanical cement removal; the underlying principles — vascularised fragment, distal cerclage, diaphyseal bypass fixation — are unchanged and should be stated as universal
- Centralisation: several health systems concentrate complex femoral revision (including ETO with Paprosky IIIB/IV femora) in revision networks or specialist centres, reflecting the volume-outcome relationship in revision arthroplasty
Controversies & Areas of Uncertainty
- Cables versus monofilament wires: cables give stronger, more fatigue-resistant fixation but generate metal debris if they fray and are implicated in trochanteric bursitis; wires are cheaper and less irritant but weaker — no high-quality comparative trial exists
- Modular versus monoblock fluted tapered stems: modularity allows independent adjustment of length, offset and version but introduces taper junction corrosion and fracture risk; modern monoblock tapered stems show comparable survivorship, and practice is shifting in some centres
- Length of stem bypass: two cortical diameters is the widely taught rule but derives from biomechanical extrapolation rather than robust clinical evidence
- ETO versus episiotomy/cortical window for cemented stem removal: shorter controlled splits (femoral episiotomy) may suffice for loose cemented stems with limited cement, avoiding a full ETO — the threshold between the two is judgement-based
- Weightbearing after modern tapered stems: several units now allow early weightbearing as tolerated with tapered stems even after ETO, arguing the taper is axially stable; traditional protocols remain protective for 6 weeks, and evidence is limited to series data
- ETO in single-stage septic exchange: increasingly reported with acceptable infection control, but patient selection criteria are not standardised
Outcomes and Evidence
Evidence
Original description of the posterior-based ETO
Younger TI, Bradford MS, Magnus RE, Paprosky WG • Journal of Arthroplasty (1995)
Finding: Described the extended proximal femoral osteotomy in difficult femoral revision, reporting reliable exposure, implant and cement removal, and predictable healing of the vascularised fragment.
Clinical implication: Established the technique now standard in revision practice; the vascularised osteomuscular sleeve is the key conceptual advance over cortical windows and uncontrolled trochanteric osteotomy.
Evidence
ETO union and complication profile in cemented revision
Paprosky WG et al (Chen, Sporer and colleagues, multiple series) • Journal of Arthroplasty / Clinical Orthopaedics and Related Research (2000s)
Finding: Series from the originating and other units consistently report osteotomy union in greater than 90-95 percent of cases, with low rates of fragment migration when 2 or more cables are used and the soft tissue sleeve is preserved.
Clinical implication: Union is the expected outcome; non-union or escape should prompt review of technique — devascularisation, inadequate fixation, or infection.
Evidence
Transfemoral approach with tapered fluted stems
Wagner H; subsequent European series (e.g. Böhm and Bischel) • Orthopäde / Journal of Bone and Joint Surgery (1987 onwards)
Finding: Wagner's transfemoral osteotomy combined with a fluted tapered revision stem achieved reliable osseointegration and proximal femoral bone restoration around the stem in long-term follow-up.
Clinical implication: Demonstrates the synergy between transfemoral exposure and diaphyseal-engaging tapered stems — the biological basis of modern ETO plus modular tapered reconstruction.
Evidence
Registry perspective on femoral revision constructs
Multiple registry reports (AOANJRR, NJR, SHAR) • Annual registry reports (Ongoing)
Finding: Registries record increasing use of modular and monoblock fluted tapered titanium stems in femoral revision, with low re-revision rates for aseptic loosening when diaphyseal fixation is achieved; ETO usage itself is not separately captured in most registries.
Clinical implication: Stem survivorship data support the diaphyseal fixation philosophy that underpins ETO reconstruction; registry evidence on the osteotomy itself remains limited to institutional series.