Revision Total Hip Replacement for Aseptic Loosening

Indication. Symptomatic aseptic loosening of a total hip replacement that has failed non-operative management (activity modification, NSAIDs, walking aids). The loosening is shown by progressive pain with activity — thigh pain points to the femoral component, groin pain to the acetabular component — together with radiographic signs: component migration greater than 2mm, progressive radiolucent lines greater than 2mm wide at the bone-implant interface, component subsidence on serial films, and osteolysis from wear debris. Constant pain at rest, fevers, chills, night sweats or a wound problem instead raise the spectre of infection. The infection gate is mandatory. Before labelling any loosening "aseptic", periprosthetic joint infection must be excluded, because infection changes the entire operation (a staged revision rather than a single-stage reconstruction). ESR and CRP alone are inadequate — they carry roughly a 30 percent false-negative rate. The workup uses the validated 2018 International Consensus Meeting (ICM)/MSIS scoring system (97.7 percent sensitivity, 99.5 percent specificity), built from serum and synovial markers plus culture. Serum markers — CRP greater than 1mg/dL (2 points), D-dimer greater than 860ng/mL (2 points), ESR greater than 30mm/hr (1 point). Synovial aspirate (the key investigation) — WBC greater than 3000 cells/µL (3 points), alpha-defensin positive (3 points), leukocyte esterase positive (3 points), PMN greater than 80 percent (2 points), synovial CRP greater than 6.9mg/L (1 point). Cultures must be held for 14 days for slow-growing organisms such as Cutibacterium acnes. Scoring — a sinus tract or two positive cultures are major criteria diagnostic of infection; otherwise an aggregate score of 6 or more defines infection. If equivocal — repeat the aspiration, add an Indium-111 WBC scan (about 90 percent sensitivity) or FDG-PET, and plan intra-operative tissue cultures (5 to 6 samples) with sonication of explanted components. If infection is confirmed, management is entirely different — a two-stage revision (explant, antibiotic spacer, 6 weeks of intravenous antibiotics, then reimplantation after the infection is eradicated). Preoperative assessment. Standard films (AP pelvis, lateral hip, full femur for long-standing loosening) define the bone loss; CT with 3D reconstruction better characterises Paprosky III defects and aids implant planning; MARS MRI assesses soft tissue (abductor quality) where metal artefact must be reduced. The bone loss is then classified with the Paprosky system (full definitions in Background & Evidence) — this dictates reconstruction. Plan the implants and the blood. Order the primary implant choice plus multiple sizes and backup options (augments, cages, modular tapered stems, strut grafts) so the correct construct is available whatever the intra-operative bone loss turns out to be — it is often worse than the imaging suggests. Revision carries a 30 to 50 percent transfusion rate, so blood management is part of the plan: preoperative haemoglobin optimisation (target greater than 120g/L, iron if ferritin is low), tranexamic acid 15 to 20mg/kg at induction repeated at 3 hours, cell saver, type and cross 2 to 4 units, and a restrictive transfusion threshold (Hb less than 70g/L, or less than 80g/L with symptoms). Consent honestly for the realities of revision: infection 2 to 5 percent, dislocation 10 to 15 percent, sciatic nerve palsy 2 to 5 percent, transfusion 30 to 50 percent, re-revision 10 to 15 percent at 10 years, and overall 10-year survival of 80 to 90 percent (versus 95 to 98 percent for a primary). Frame it as salvage for pain relief and function, not a return to high-impact activity. Setup. Lateral or supine depending on approach, on a radiolucent table with intra-operative fluoroscopy available. Reuse the previous surgical approach when possible — it is usually extensile in revision. General or regional anaesthesia with multimodal analgesia.

The goal: exclude infection, expose the hip through the previous approach, identify and protect the sciatic nerve early, remove both loose components while preserving every scrap of host bone, curette all osteolysis to bleeding bone, and reconstruct the acetabulum and femur to a stable construct in the anatomic hip center. The exposure — laid out in full below and in depth on the posterior (Moore/Southern) approach to the hip page — is the heart of the operation.

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Weight bearing. Weight-bear-as-tolerated when the construct is well-fixed with no ETO, no strut graft and no fracture. Touch-down or partial weight bearing (about 20kg) for 6 to 12 weeks after an ETO, where strut grafts were used, where fixation is questionable, or after an intra-operative fracture. Non-weight-bearing is rare, reserved for an unstable construct. Progress from walker or crutches (6 to 12 weeks) to a single crutch, then cane, then independent. Hip precautions (posterior approach) — STRICT for 12 weeks (longer than the 6 weeks after a primary): no hip flexion greater than 90 degrees (elevated toilet seat, no bending forward), no adduction past midline (no crossing legs; abduction pillow in bed), no internal rotation (no pivoting on the operative leg), and sleep supine or on the operative side with a pillow between the legs. Post-operative management.

• Antibiotics: IV for 24 to 48 hours peri-operatively only (cefazolin 2g q8h, or vancomycin 15mg/kg q12h if MRSA risk); longer courses do not reduce infection.
• DVT prophylaxis is critical (revision is high-risk): LMWH (enoxaparin 40mg SC daily) or a DOAC (rivaroxaban 10mg PO daily, or apixaban 2.5mg PO BID) for 4 to 6 weeks minimum, plus mechanical prophylaxis and early mobilisation.
• Multimodal analgesia: scheduled paracetamol 1g q6h, an NSAID if not contraindicated (celecoxib 200mg PO BID), opioids sparingly, and regional anaesthesia where available.
• Transfusion: check haemoglobin 6 to 12 hours post-op; transfuse if Hb less than 70g/L, or less than 80g/L with symptoms (each unit raises Hb by about 10g/L).
• Monitoring: frequent neurovascular checks (foot dorsiflexion/plantar flexion, sensation, pulses) with a documented baseline; any new deficit is investigated immediately.
• Imaging: AP pelvis and lateral hip within 24 to 48 hours to document component positions, exclude fracture and establish a baseline.
• Discharge (days 3 to 5): pain controlled on oral medication, medically stable, mobilising safely with an aid, and adequate social support or rehab transfer arranged. Follow-up. 2 weeks (wound, remove staples), 6 weeks (radiographs, advance weight bearing if protected), 3 months (discontinue precautions at 12 weeks), 6 months (baseline), then annually for life with serial films to watch for migration, radiolucent lines and osteolysis — early re-revision before extensive bone loss gives better outcomes (and roughly 20 percent of painful revisions harbour occult infection, so re-workup first).

Why it matters. Paprosky classification is essential for revision planning: the type determines the reconstruction, and preoperative classification ensures the correct implants and instruments are on the table.

Why it matters. The ETO is the standard technique for removing a well-fixed cementless or extensively coated stem and for distal cement access, while preserving the abductor-trochanter blood supply for reliable union. Non-union runs 5 to 10 percent with inadequate fixation or early weight bearing.

Epidemiology. Aseptic loosening and polyethylene-wear osteolysis are among the leading indications for revision hip arthroplasty worldwide. Convergent registry data (AOANJRR Australia; NJR England, Wales, Northern Ireland and Isle of Man; the Swedish and Norwegian arthroplasty registers; AJRR USA) consistently show that second-revision survivorship is lower than first-revision survivorship, that dislocation and re-revision rates after revision THR exceed those of primary THR, and that aseptic loosening and osteolysis remain leading revision indications globally. Over time the indications have shifted: aseptic loosening has declined as implants have improved, while wear and osteolysis are now prominent and infection accounts for roughly 15 to 20 percent of revisions. Pathoanatomy. Aseptic loosening begins at the bone-implant interface with particulate debris — overwhelmingly polyethylene, plus metal and cement fragments — phagocytosed by macrophages that release cytokines driving an osteolytic cascade. The resulting granulation membrane and bone resorption produce a fibrous interface instead of stable fixation, allowing component migration, progressive radiolucent lines and osteolytic cysts. The pain pattern follows the component (groin for acetabular, thigh for femoral), and progressive bone loss compounds the problem at each subsequent revision. Paprosky classification — the planning backbone. The Paprosky acetabular and femoral classifications remain the gold standard for describing bone loss and matching it to a reconstruction strategy. They are graded so that preoperative classification ensures the correct implants and instruments are on the shelf at surgery.

Key evidence. Paprosky's 1994 acetabular paper established the classification and showed that of 147 revised cups only 6 (4 percent) were unstable — all Type 3B — confirming that massive rim/column loss carries the highest failure risk and needs structural support. Della Valle and Paprosky (2004) extended the framework to the femur: the key question is how much intact diaphysis remains distal to the bone loss, dictating whether diaphyseal fixation is achievable. Parvizi and colleagues (2018) gave the field the validated 2018 ICM/MSIS scoring for periprosthetic infection (97.7 percent sensitivity / 99.5 percent specificity), anchoring the infection gate that must precede any "aseptic" revision. Younger and colleagues (1995) described the extended trochanteric osteotomy — the controlled anterior osteotomy that preserves the abductor-trochanter blood supply and enables safe removal of well-fixed stems. Sporer and Paprosky (2006) showed that trabecular-metal cups, with or without augments, achieve reliable fixation across a pelvic discontinuity by spanning it.

Further reading 1. Chen AF, Hozack WJ. Component optimization in revision total hip arthroplasty. Orthop Clin North Am. 2014;45(2):161-167. Comprehensive review of implant selection for revision hip arthroplasty based on bone loss — extensively coated stems, modular tapered stems, trabecular-metal cups, augments, and cages. 2. Younger AS, Duncan CP, Masri BA. Surgical exposures in revision total hip arthroplasty. J Am Acad Orthop Surg. 1997;5(1):55-64. Detailed surgical approach options for revision hip surgery — extended posterolateral approach, trochanteric slide, extended trochanteric osteotomy, and management of prior surgical approaches. 3. National joint replacement registries (AOANJRR Australia; NJR England, Wales, NI and IoM; Swedish Arthroplasty Register; Norwegian Arthroplasty Register; AJRR USA). Annual Reports, latest editions. Convergent registry data show second-revision survivorship is consistently lower than first revision, dislocation and re-revision rates after revision THR exceed those of primary THR, and aseptic loosening and osteolysis remain leading indications for revision worldwide — used here as global evidence rather than a single-country frame. 4. Lachiewicz PF, Soileau ES. Changing indications for revision total hip arthroplasty. J Surg Orthop Adv. 2005;14(2):82-84. Evolution of revision hip indications over time — aseptic loosening declining due to improved implants, polyethylene wear and osteolysis now leading indications, infection remaining 15 to 20 percent of revisions. 5. Masri BA, Meek RM, Duncan CP. Periprosthetic fractures evaluation and treatment. Clin Orthop Relat Res. 2004;(420):80-95. Comprehensive review of periprosthetic femoral fractures in revision hip surgery — Vancouver classification system, treatment algorithms based on fracture location and component stability, role of strut grafts and cerclage wires.