Total Hip Arthroplasty - Revision with Extended Trochanteric Osteotomy

Indication. An Extended Trochanteric Osteotomy (ETO) is performed during a revision total hip arthroplasty whenever you need DIRECT, controlled access to the femoral canal - most often to remove a well-fixed stem or a long cement mantle that cannot be extracted safely through a closed canal. It converts a blind, dangerous extraction into an open, visualised one. Primary indications - Well-fixed cemented stem requiring removal - the commonest indication (about 60 percent of ETOs). The stem is bonded to a long cement mantle and cannot be extracted safely; the ETO exposes the cement-bone interface for complete removal under vision (blind removal through cortical windows perforates the anterior cortex in about 30 percent of cases).

• Well-fixed uncemented stem requiring removal - an extensively porous-coated or hydroxyapatite-coated stem with circumferential bone ingrowth that will not come out with osteotomes or a slap hammer and would fracture the femur if forced.
• Periprosthetic femoral fracture (Vancouver B1/B2) - Vancouver B1 (fracture around a well-fixed stem) and B2 (fracture around a loose stem) both need access for reduction and fixation; an ETO allows stem extraction and fracture management through the same exposure.
• Proximal femoral deformity limiting canal access - previous fracture malunion, Paget's disease, a previous femoral osteotomy, or developmental dysplasia, where the canal cannot be reamed in a controlled line.
• Severe proximal femoral osteolysis - extensive cysts from polyethylene wear debris needing thorough debridement and grafting. Relative indications include a retained cement restrictor or distal plug that blocks instruments, broken cerclage wires embedded in bone, a severe anterior femoral bow risking anterior perforation during reaming, and removal of a long distally-fixed stem. Contraindications. Absolute: active uncontrolled infection with soft-tissue loss (fragment contamination), severe osteoporosis (the fragment will not hold cables), a prior non-union of an ETO at the same site (use plate fixation instead), and destruction of the trochanteric area by tumour or infection (no fragment to mobilise). Relative: mild osteoporosis, anticipated non-compliance with protected weight-bearing, smoking (threefold non-union risk - counsel cessation and consider plate augmentation), previous femoral irradiation, and morbid obesity.

Preoperative planning. Full-length AP and lateral femur radiographs (hip to knee on one cassette) are mandatory. Measure the existing stem from shoulder to tip; the ETO must extend 4-5 cm beyond the tip, giving a typical total ETO length of 8-12 cm from the greater trochanter. Mark the stem tip and the planned distal osteotomy cut on the film. Assess the distal bone stock and canal diameter to assign a Paprosky femoral grade (defined in Background and Evidence), which dictates the revision stem. Order the cement-removal equipment (an ultrasonic system such as OSCAR, or a high-speed burr with long carbide bits, and curved osteotomes) and 5-7 cerclage cables with a tensioner. Exclude infection in every revision. ESR greater than 30 mm/hr or CRP greater than 10 mg/L raises suspicion (combined sensitivity around 95 percent); aspirate if there is any concern - a synovial WBC count greater than 3000 cells per microlitre or PMN greater than 80 percent is diagnostic. Consent. Counsel specifically on the ETO-related risks: non-union 5-10 percent, trochanteric escape 2-5 percent, intraoperative fracture 5-10 percent, sciatic nerve injury 0.5-2 percent, infection 2-5 percent, dislocation 5-10 percent, subsidence 5-10 percent, and chronic pain 10-15 percent; and on the mandatory 6-8 week protected weight-bearing protocol. Typical operative time is 3-4 hours with 800-1200 mL blood loss (cross-match 4 units). Optimise smoking cessation (at least 4 weeks preop), nutrition (albumin greater than 3.5 g/dL), diabetes (HbA1c less than 7 percent), and anaemia before listing.

The goal is to expose the femur through the posterior approach, elevate the anterior two-thirds of vastus lateralis while PRESERVING the posterior third (the fragment's blood supply), create a controlled anterolateral osteotomy that hinges open on that intact posterior sleeve, remove the stem and all cement under direct vision, ream and insert a revision stem that bypasses the ETO by 10 cm, then reduce the fragment and compress it with cerclage cables. The exposure and osteotomy are the whole operation - laid out step by step below.

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Rehabilitation - phased protected weight-bearing (MANDATORY until union) | Phase | Timing | Weight-bearing | Focus | |-------|--------|----------------|-------| | 1 | 0-6 weeks | Toe-touch or 20 kg partial with a walker | ETO healing, hip precautions, DVT prophylaxis; ankle pumps, quad and glute sets, gentle ROM within precautions | | 2 | 6-12 weeks | Advance per radiograph: 50 percent at 6 weeks if callus, full by 12 weeks | Confirm union (bridging callus on 3 of 4 cortices); progress crutch then cane; add abductor strengthening | | 3 | 3-6 months | Full, once union confirmed | Restore abductor strength and gait; low-impact cardio (bike, swim) | | 4 | 6-12 months and beyond | Full, maintenance | Lifelong avoidance of high-impact activity (running, contact sport, heavy lifting over 50 lb) | Hip precautions (6 weeks, posterior approach): no flexion past 90 degrees, no adduction past the midline, no internal rotation, and never the combined flexion-adduction-internal rotation that dislocates posteriorly. Use a raised toilet seat, reacher, and slip-on shoes; no driving until off opioids and full weight-bearing (around 3 months). Radiographic surveillance. X-ray at 2 weeks (wound, component position), 6 weeks (early callus - advance weight-bearing if bridging on 2 or more cortices, otherwise continue protection and repeat at 8-10 weeks), and 12 weeks (union equals bridging callus on 3 of 4 cortices, no lucency - advance to full weight-bearing). Then 6 months, 1 year, and annually to 5 years; every 2 years thereafter if stable. Union is mean 6-8 weeks (up to 12). Obtain a CT if union is doubtful. Red flags - contact urgently: sudden pain and inability to bear weight (fracture or dislocation), fever or wound drainage (infection), progressive pain despite compliance (loosening, infection, non-union), and new foot drop (sciatic nerve).

Evolution of the technique. Wagner (1987) first described an anteriorly-based femoral osteotomy for revision, but it had high non-union (20-30 percent) and needed rigid plating. In 1995 Younger, Bradford, Magnus and Paprosky described the modern laterally-based extended trochanteric osteotomy - cutting one-third of the femoral circumference, extending it distally and levering it open on an intact anterolateral muscle-osseous sleeve (gluteus medius, greater trochanter, anterolateral diaphysis, vastus lateralis), repaired with cerclage cables rather than a plate. Their first 20 patients healed reliably with no change to the postoperative regimen. Multiple series since have confirmed union over 90 percent (many over 95 percent); Mardones (Mayo, 2005) reported 73 of 74 retained osteotomies healing without further procedure. Today the ETO is the standard approach worldwide for removing well-fixed cemented and uncemented stems; Paprosky's lateral modification, paired with the posterior approach, has replaced both the original anterior osteotomy and cortical windows. Paprosky femoral bone-loss classification (guides stem selection during ETO)

Union and outcomes. Modern series report union in over 90 percent (Younger 1995; Mardones 2005), up to 98 percent in contemporary Mayo data (Wyles and Abdel 2023) and long-ETO series (Lakstein 2009, 98.1 percent). Union is bridging callus across the osteotomy; mean fragment migration before union is about 3 mm, with clinically significant migration (over 1 cm) in about 7 percent. The keys to union are preserved fragment vascularity, anatomic reduction, adequate cerclage compression, and protected weight-bearing. Closure typically uses 3-4 cerclage cables or double-stranded Luque wires (one prophylactic distal cable, diaphyseal cables, one above the lesser trochanter); compression across the interface is the mechanical principle that drives union. Cable number and tension are individualised to bone quality rather than maximised. Stem selection outcomes. For Paprosky IIIA (more than 4 cm of supportive diaphysis), extensively porous-coated cylindrical or fluted tapered stems achieve a diaphyseal scratch-fit (around 4-6 cm controls subsidence). For IIIB and IV, modular fluted tapered stems, allograft-prosthetic composite, or proximal femoral replacement are used. Registry and series data favour uncemented diaphyseal-fixation stems over cemented revision stems in this setting; cementing into an osteotomised, sclerotic femur is generally avoided. Why ETO replaced cortical windows. The ETO gives direct visualisation of the cement-bone interface for complete cement removal under vision; blind removal through cortical windows or a closed canal carries a substantially higher femoral perforation and retained-cement risk. This visualisation advantage, not speed, is the principal reason ETO has replaced cortical windows. Guidelines, registries and global practice. National joint registries (NJR England and Wales, AOANJRR Australia, Swedish and Norwegian registers, AJRR USA) consistently report aseptic loosening, infection, instability or dislocation and periprosthetic fracture as the leading indications for revision THA - the situations in which an ETO is most often needed - and favour uncemented diaphyseal-fixation stems for durable revision fixation. An ETO itself does not increase re-revision risk when used appropriately; outcomes are driven by the underlying pathology (especially infection) and bone stock. A single appropriate antibiotic within 60 minutes of incision is standard worldwide (AAOS, NICE, WHO), with no benefit to prophylaxis beyond 24 hours. For high-risk heterotopic ossification, a short NSAID course or single-fraction perioperative radiotherapy is effective. Mechanical plus chemical VTE prophylaxis (aspirin, LMWH, or a direct oral anticoagulant) is recommended after revision THA, with extended duration commonly used given the prolonged reduced mobility during protected weight-bearing.