Adult reconstruction · Advanced · Periprosthetic joint infection
- Diagnosis: a major criterion (a sinus tract communicating with the joint, OR 2 positive cultures of the same organism) is definite PJI; otherwise apply the 2018 ICM weighted score — a score of 6 or greater is infected.
- Two-stage exchange is the most validated strategy for chronic PJI (symptoms present for greater than 4 weeks), with infection eradication around 85-95% in pooled series.
- Take 5 or more separate deep tissue samples for culture BEFORE giving antibiotics — this raises organism detection from about 65% toward 95%.
- High-dose treatment cement per 40g pack: up to about 4g vancomycin plus about 3.6g tobramycin; keep the total antibiotic under about 10% by weight or the spacer fractures.
- An extended trochanteric osteotomy (ETO) for a well-fixed cementless stem protects the femur, aids extraction, and unites in about 95-98%.
- An articulating spacer is preferred for the hip — it maintains mobility and leg length; the 10-20% dislocation rate is accepted because local cement antibiotic levels exceed systemic levels by orders of magnitude, which is critical for biofilm penetration.
When & Why
Indication. Two-stage exchange is the workhorse strategy for an established (chronic) periprosthetic joint infection — symptoms present for greater than 4 weeks with positive diagnostic criteria — and for a failed DAIR (Debridement, Antibiotics and Implant Retention), infection with a difficult-to-treat organism (MRSA, resistant Gram-negatives, fungi), culture-negative PJI where the organism is unknown, or a failed one-stage revision. In pooled series it achieves infection eradication in about 85-95%. Choose the right strategy. The decision rests on symptom duration, the organism, the soft-tissue envelope, bone stock and host fitness, not on adding hardware:
The default for chronic PJI. Stage 1 removes the implants, radically debrides the joint and leaves an antibiotic-loaded cement spacer; after 6 weeks of IV antibiotics and an antibiotic holiday, stage 2 reimplants once criteria are met. Most validated, highest eradication, and fits any organism.
Reserved for strict criteria: a known sensitive organism on pre-operative cultures, a healthy soft-tissue envelope, good bone stock, a non-immunocompromised patient and a Gram-positive sensitive organism. Single sitting, but the criteria are rarely met in chronic infection.
Appropriate only for ACUTE infection (symptoms for less than 3-4 weeks) with stable well-fixed implants, a healthy patient, a known sensitive organism and exchangeable modular components. Not for chronic infection.
Infection workup is essential. Aspirate the hip OFF antibiotics for at least 2 weeks and send the aspirate for cell count and differential (synovial WBC greater than 3000, PMN greater than 80% support PJI), Gram stain, culture (aerobic, anaerobic, fungal and AFB) and crystal analysis to exclude gout. Check serum ESR, CRP and WBC (ESR greater than 30, CRP greater than 10 support PJI), and add a WBC-labelled nuclear scan if the diagnosis remains uncertain. Plain radiographs assess component position, loosening and bone loss; a CT assesses bone stock and collections for reconstruction planning; and identify the implant manufacturer and size so the correct extraction equipment is available. Medical optimization. Correct nutrition (albumin greater than 3.0, transferrin greater than 200, lymphocytes greater than 1500), control diabetes (HbA1c less than 8%), hold immunosuppression where possible with infectious-disease input, and plan anticoagulation with appropriate cessation or bridging. Surgical planning. Use the previous approach (posterior is most common); plan an ETO if the stem is well-fixed and have the equipment ready; cross-match 4 units as high blood loss is expected; and book an ICU bed for the medically complex patient. Consent specifically for persistent infection requiring further procedures (10-20%), spacer dislocation (10-20%), spacer fracture (5-10%), intraoperative femur or acetabular fracture (5-10%), sciatic nerve injury (2-5%, usually neuropraxia), wound complications (5-15%), and the small possibility of a Girdlestone resection arthroplasty (5-10%) if infection cannot be controlled. Counsel that stage 1 is a temporising step, not a definitive procedure: 8-12 weeks with a spacer in situ, toe-touch weight bearing, 6 weeks of IV antibiotics via a PICC line and possibly an antibiotic holiday before stage 2. Discuss the alternatives — DAIR, one-stage revision, chronic suppressive antibiotics, resection arthroplasty, or (rarely) above-knee amputation for life-threatening sepsis. Setup. Lateral decubitus for a posterior approach, with the hip flexed about 30 degrees.
The Operation
The goal: confirm and sample the infection, remove all implants and cement, radically debride the joint, lavage copiously, and insert a high-dose antibiotic-loaded cement spacer that delivers local antibiotic and maintains soft-tissue tension until stage 2. The exposure is laid out in full as the first steps below (and in depth on the posterior (Moore/Southern) approach to the hip page).
Operative sequence
- Critical: obtain cultures BEFORE any prophylactic antibiotic is given. Hold antibiotics until 5 or more samples are taken.
- Take a minimum of 5 separate tissue samples from: the pseudocapsule (3 samples from different sites), the interface membrane around the acetabular component, the interface membrane around the femoral component, any obvious purulent collection, and a synovial fluid aspiration.
- Each sample goes in its own separate sterile container, clearly labelled with its site. Send for aerobic, anaerobic, fungal and AFB culture, and request prolonged culture (14 days) for low-virulence organisms.
- Use the previous surgical approach — most commonly the posterior (Moore or Southern) approach. Lateral decubitus, hip flexed about 30 degrees.
- Incise through the previous scar, extending as needed for visualization. Expect dense scarring and dissect carefully in tissue planes.
- Identify and protect the sciatic nerve early — it lies about 3-4cm posterior to the hip joint.
- Tag the short external rotators with sutures for later repair if they are salvageable.
- An extended incision is often needed; an anterior approach is acceptable if it was the previous approach; and a trochanteric osteotomy is reserved for severe scarring or heterotopic ossification.
- Perform a radical synovectomy: complete excision of the pseudocapsule, removal of all granulation tissue, debridement of necrotic tissue to healthy bleeding margins, removal of all foreign material (sutures, cement debris), and debridement of bone surfaces to healthy bleeding bone.
- Radical debridement is the single most important factor for infection eradication — inadequate debridement means treatment failure regardless of the antibiotics given.
- Cemented cup: identify the cement-bone interface, disrupt it with curved osteotomes, lever the cup out progressively while protecting the posterior wall, then remove ALL cement with curettes, osteotomes and a high-speed burr.
- Uncemented cup: pass curved osteotomes around the rim to disrupt bone ingrowth; avoid aggressive levering (acetabular fracture risk); use specialized extraction devices for well-fixed components; an acetabular rim osteotomy may be needed for extraction.
- Keep retractors ON bone at all times — the femoral vessels lie medial to the acetabulum anteriorly and catastrophic haemorrhage follows anterior retractor slippage.
- Assess: is the stem loose or well-fixed?
- If loose: extract with a slap hammer and trunnion extractors; remove all cement if it is a cemented design — relatively straightforward.
- If well-fixed (cementless): STOP. Do NOT attempt brute-force extraction. Proceed to an extended trochanteric osteotomy.
- Indication: a well-fixed cementless stem, a distally fixed stem, or a cement mantle requiring removal.
- Mark the osteotomy length — usually 12-15cm, extending 2-3cm beyond the stem tip.
- Apply prophylactic cerclage at the distal extent of the planned osteotomy before cutting.
- Use an oscillating saw for the lateral and anterior cortical cuts, then create a controlled crack from lateral to medial with osteotomes.
- Open the trochanteric fragment like a "book", maintaining its posterior muscle attachments (abductors, vastus lateralis). The femoral component and cement are now accessible and removed under direct vision.
- ETO preserves abductor attachment, protects the femur, allows complete cement removal, and heals reliably in 95% or more.
- Remove ALL cement — any retained cement harbours bacteria in its crevices. Use a high-speed burr for cement on cortical bone, long curettes for canal cement, and ultrasonic tools if available.
- Serially ream the medullary canal to fresh bleeding bone, remove all interface membrane, and brush the canal walls.
- Use a minimum of 9 litres of pulsatile lavage: 3-6L during debridement and 3L as a final lavage before spacer insertion.
- Use a pulsatile lavage system, not a bulb syringe. Some surgeons add betadine, chlorhexidine or hydrogen peroxide, but the evidence is mixed and saline remains the mainstay.
- "Dilution is the solution to pollution" — high-volume pulsatile lavage mechanically removes bacteria, debris and planktonic organisms.
- High-dose treatment formulation (per 40g pack): cement (2-3 packs depending on spacer size; Palacos is favoured for its elution characteristics) plus vancomycin up to about 4g (Gram-positive, MRSA coverage) plus tobramycin about 3.6g OR gentamicin about 2-4.8g (Gram-negative, biofilm penetration). Keep the total antibiotic under about 10% by weight to preserve mechanical strength.
- Note that the highest loading does NOT guarantee the best elution — about 3g tobramycin plus 2g vancomycin per 40g maximises cumulative release in vitro but reduces compressive strength, so balance dose against spacer durability.
- Mixing: mix the antibiotic powders into the cement powder FIRST (before the liquid monomer), ensure homogeneous distribution, add the liquid monomer, then mix to a doughy consistency and mould.
- Spacer type: an articulating spacer is preferred (hand-moulded or modular systems such as Prostalac, STAGE or Interspace); a static spacer is reserved for severe bone loss, instability, or a medically unfit patient who will not mobilize.
- Hand-moulded: form the cement around a Steinmann pin or K-wire for reinforcement, create a stem shape that fits the canal, insert in the doughy phase and seat firmly with neutral alignment and about 10-15 degrees of anteversion.
- Commercial systems: follow the manufacturer technique, select the size based on canal dimensions, and ensure a stable press-fit.
- The cement should interdigitate with cancellous bone for stability; maintain leg length (avoid excessive shortening).
- Options: an articulating spacer head cemented onto the femoral component that articulates against the native acetabulum (or an augmented cup); cement packed into the acetabular defect; or a pre-formed commercial acetabular spacer component.
- Size the head appropriately for stability (larger is more stable), ensure coverage by the acetabulum, and accept some bone loss for reconstruction at stage 2.
- Test stability in multiple positions: hip flexion to 90 degrees with internal rotation, and extension with external rotation. Assess for impingement and dislocation.
- If unstable: use a larger head size, adjust offset if possible, consider a constrained liner at stage 2, accept the inherent 10-20% dislocation risk, and consider an abduction brace post-operatively.
- Layered closure: 2 deep drains minimum to the antibiotic-loaded cavity; repair the capsule and short external rotators if possible; close the fascia lata with strong absorbable suture; subcutaneous absorbable suture; skin with staples or absorbable subcuticular.
- Use a VAC dressing if there is wound compromise or a planned return to theatre. Tension-free closure is essential — skin necrosis means an exposed spacer and failure.
- Document all tissue samples taken (sites and culture requests), the components removed (manufacturer, size, condition), intraoperative findings (purulence, membrane, bone loss), the spacer type and antibiotic content, and the stability assessment.
- Specimen handling: each tissue sample in a separate container, clearly labelled with its site; request 14-day prolonged culture; explanted components can be sent for sonication (biofilm disruption).
Previous surgery creates scar tissue that obscures normal anatomy. Identify the sciatic nerve early — it lies about 3-4cm posterior to the hip joint — and protect it throughout, limiting retraction and avoiding leg lengthening greater than 4cm. The superior gluteal nerve exits the greater sciatic notch about 4-5cm above the greater trochanter tip, so limit any gluteus medius split to 5cm. Keep acetabular retractors ON bone: the femoral vessels lie medial to the acetabulum anteriorly and injury causes catastrophic haemorrhage. Consider intraoperative nerve monitoring in complex revisions.
Attempting extraction of a well-fixed cementless stem without an extended trochanteric osteotomy risks a proximal femur fracture in 30% or more of cases. Always plan and perform an ETO when a cementless revision is anticipated, and apply prophylactic cerclage in the osteopenic femur.
Exceeding about 10% antibiotic by weight weakens the cement mechanically and risks spacer fracture. Balance antibiotic delivery against structural integrity — optimise the dose rather than maximise it.
Taking 5 or more separate deep tissue samples BEFORE prophylactic antibiotics increases organism detection from about 65% to about 95%. Never start antibiotics until sampling is complete.
The spacer dislocation rate of 10-20% is accepted. Prioritise infection eradication over perfect stability — patients are on protected weight bearing anyway, and a constrained liner can be used at stage 2 if needed.
Aftercare & Complications
Rehabilitation | Phase | Timing | Weight bearing / immobilisation | Therapy / monitoring | |-------|--------|--------------------------------|----------------------| | 1 — Immediate | 0-2 weeks | Toe-touch weight bearing with frame or crutches; DVT prophylaxis (LMWH or aspirin); drains out when less than 50mL per 24 hours (usually day 2-3) | IV antibiotics started post-operatively — empiric initially, then culture-directed | | 2 — Antibiotic course | 6 weeks | Protected weight bearing; PICC line for OPAT (home or infusion centre) | IV antibiotics tailored to sensitivities; weekly CRP and ESR (expect an initial rise then a gradual fall); infectious-disease involvement | | 3 — Spacer interval | 6-12 weeks | Protected weight bearing; abduction brace if marginal stability | Watch for spacer dislocation (sudden pain, shortening), fracture, and persistent drainage | | 4 — Stage 2 | When criteria met | Reimplantation once infection cleared | Reassess markers, aspirate during the holiday, reimage for reconstruction | Criteria for stage 2 (exam-essential):
- A minimum of 6 weeks of IV antibiotics completed.
- A 2-6 week antibiotic holiday to allow re-aspiration.
- Normalised inflammatory markers — CRP less than 10 and ESR less than 30 for 2 or more consecutive weeks.
- A negative aspiration during the antibiotic holiday.
- A healed wound with no drainage.
- No clinical signs of infection.
Persistent infection equals stage-2 failure. Wait until ALL criteria are met. The typical interval is 8-12 weeks but may be longer.
Complications
- Recognition
- Non-normalising CRP/ESR, positive re-aspiration, ongoing symptoms
- Prevention
- Radical debridement, adequate antibiotics, proper patient selection
- Management
- Repeat stage 1 (spacer exchange); consider suppression or Girdlestone
- Recognition
- Sudden pain, leg shortening, loss of mobility, visible deformity
- Prevention
- Appropriate sizing, test stability, abduction brace if marginal
- Management
- Closed reduction; if recurrent, a constrained spacer or advance to stage 2
- Recognition
- Increased pain, loss of height, instability, radiographic fracture
- Prevention
- Maximum 10% antibiotic, adequate cement thickness, protected weight bearing
- Management
- Conservative if stable fragments; spacer exchange if displaced or unstable
- Recognition
- Visible fracture during extraction, cortical perforation
- Prevention
- ETO for fixed stems, prophylactic cerclage, gentle technique
- Management
- Cerclage or plating; longer reconstruction at stage 2
- Recognition
- Foot drop, sensory loss, weakness post-operatively
- Prevention
- Identify and protect the nerve, limit retraction, avoid lengthening greater than 4cm
- Management
- Document pre-op function; observe 3-6 months; EMG if not improving
- Recognition
- Wound breakdown, drainage, exposed spacer
- Prevention
- Tension-free closure, drains, optimise nutrition and diabetes
- Management
- VAC therapy; flap coverage if the spacer is exposed; may need repeat debridement
- Recognition
- Leg swelling, tachycardia, hypoxia, chest pain
- Prevention
- LMWH prophylaxis, early mobilization, mechanical prophylaxis
- Management
- Therapeutic anticoagulation; IVC filter if recurrent or contraindicated
- Recognition
- Persistent infection despite multiple procedures
- Prevention
- Optimise debridement, antibiotics and patient selection
- Management
- Accept as final outcome — mobility aids, shoe raise, chronic pain management
Viva & Exam Focus
SPACERSPACER — antibiotic cement formulation
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
“A 68-year-old presents 2 years after a primary THA with a chronically draining sinus over the lateral hip. Describe your assessment and management plan.”
“During stage 1 revision for PJI you encounter a well-fixed cementless stem. How do you proceed?”
“What factors determine whether you use a static versus an articulating spacer in two-stage revision for hip PJI?”
PJI diagnosis (2018 ICM)
- MAJOR (definite PJI): a sinus tract OR 2 positive cultures of the same organism
- Weighted: CRP and D-dimer score 2, ESR 1; synovial WBC, alpha-defensin and leucocyte esterase score 3; PMN% and synovial CRP score 2
- A score of 6 or greater is infected; 2-5 inconclusive (add intra-op findings); 0-1 not infected
- Hold antibiotics for 2 or more weeks before aspiration for accurate cultures
Antibiotic cement formula
- Per 40g pack: up to about 4g vancomycin plus about 3.6g tobramycin (or gentamicin)
- Powder-into-powder FIRST, then add the liquid monomer
- Keep total antibiotic under about 10% by weight (or mechanical failure)
- Articulating spacer preferred for the hip (10-20% dislocation accepted)
Critical operative steps
- 5 or more tissue samples BEFORE antibiotics (about 95% sensitivity)
- Radical debridement — the single most important factor
- ETO for well-fixed cementless stems (30% or more fracture without one)
- 9L or more of pulsatile lavage — 'dilution is the solution to pollution'
Stage 2 criteria
- 6 weeks of IV antibiotics completed
- A 2-6 week antibiotic holiday
- CRP less than 10 and ESR less than 30 for 2 or more consecutive weeks
- A negative aspiration during the antibiotic holiday
- Typical interval 8-12 weeks — do not rush
Background & Evidence
Epidemiology and rationale. Periprosthetic joint infection is among the most devastating complications of total hip arthroplasty and carries a substantial economic burden (Kurtz, 2012). For established chronic infection — symptoms present for greater than 4 weeks — two-stage exchange with an antibiotic-loaded cement spacer is the most validated strategy, achieving eradication in about 85-95% in pooled series. The rationale for a spacer is that periprosthetic infection is a biofilm disease: organisms adhere to the implant surface within a glycocalyx that is largely impermeable to systemic antibiotics and to host defences. Removing the implants and all cement eliminates the biofilm substrate; radical debridement clears the infected tissue; and a high-dose antibiotic-loaded cement spacer delivers local antibiotic concentrations that exceed systemic levels by orders of magnitude, penetrating the biofilm while maintaining the dead space and soft-tissue tension between stages.
- Threshold
- A sinus tract communicating with the joint, OR 2 positive cultures of the same organism
- Score
- Definite PJI
- Threshold
- Greater than 1 mg/dL
- Score
- 2
- Threshold
- Greater than 860 ng/mL
- Score
- 2
- Threshold
- Greater than 30 mm/h
- Score
- 1
- Threshold
- Greater than 3000 per microL
- Score
- 3
- Threshold
- Greater than 80%
- Score
- 2
- Threshold
- Positive (++)
- Score
- 3
- Threshold
- Elevated
- Score
- 1
- Threshold
- 6 or greater is infected; 2-5 inconclusive (add intra-op histology, purulence, single culture); 0-1 not infected
- Score
- —
Articulating versus static spacer. The modern preference for an articulating spacer is evidence-supported. Hsieh et al. compared antibiotic-loaded cement beads against an articulating antibiotic-loaded cement prosthesis in 128 consecutive two-stage revisions (70 beads, 58 spacer) at a mean 4.9-year follow-up and found no recurrent infection in 122 of 128 patients (95.3%), with similar eradication in both groups but markedly better interim hip scores, walking capacity and shorter hospital stay in the spacer group, plus easier stage-2 reimplantation. Custom-made interval spacers (Younger) and cementless two-stage protocols (Masri; Fink) corroborate reliable eradication with a staged approach. Extended trochanteric osteotomy. The ETO is the workhorse for safe extraction of a well-fixed femoral stem: King et al. reported an osteotomy union rate of 98% with a proximally porous-coated calcar-replacement stem and no component loosening at short-term follow-up, confirming the ETO heals reliably while facilitating femoral reconstruction. Optimising cement antibiotic loading. Slane et al. showed in vitro that the highest antibiotic loading did not yield the best elution: about 3g tobramycin plus 2g vancomycin per 40g of Palacos R gave the greatest cumulative release but significantly reduced compressive strength and increased porosity, and tobramycin eluted more effectively than vancomycin. The principle is to optimise rather than maximise spacer antibiotic loading.
References
The 2018 Definition of Periprosthetic Hip and Knee Infection: An Evidence-Based and Validated Criteria
- Multi-institutional derivation (684 PJI, 820 aseptic) with external validation (222 PJI, 200 aseptic)
- Two positive cultures of the same organism or a sinus tract remain major criteria diagnostic of PJI
- Weighted preoperative score: CRP and D-dimer 2 points, ESR 1, synovial WBC/alpha-defensin/leucocyte esterase 3, PMN% 2, synovial CRP 1
- Aggregate score of 6 or more equals infected; sensitivity 97.7% vs 79.3% (MSIS) and 86.9% (prior ICM), specificity 99.5%
New definition for periprosthetic joint infection: from the Workgroup of the Musculoskeletal Infection Society
- First standardised consensus definition of PJI, establishing the major/minor criteria framework
- Major criterion: a sinus tract communicating with the prosthesis OR a pathogen isolated from 2 or more separate tissue or fluid cultures
- Minor criteria included elevated ESR and CRP, raised synovial WBC, elevated synovial PMN%, purulence, and positive histology
- Created a common diagnostic language enabling reproducible PJI research and reporting
Two-stage revision hip arthroplasty for infection: comparison between the interim use of antibiotic-loaded cement beads and a spacer prosthesis
- 128 consecutive two-stage revisions, mean follow-up 4.9 years (70 cement beads, 58 antibiotic-loaded cement prosthesis or spacer)
- No recurrent infection in 122 of 128 patients (95.3%), with similar infection-free rates in both groups
- The spacer prosthesis gave higher interim hip scores, better walking capacity and shorter hospital stay
- The spacer group had reduced reimplantation operative time, less blood loss and fewer interim dislocations
Extended femoral osteotomy and proximally coated prosthesis for hip revision
- 45 revision THA cases using an extended trochanteric osteotomy with a proximally porous-coated calcar-replacement stem
- Osteotomy union rate of 98%
- No femoral component was radiographically loose and none were revised for loosening at short-term follow-up
- Demonstrates the ETO heals reliably while facilitating femoral reconstruction
Antibiotic elution from acrylic bone cement loaded with high doses of tobramycin and vancomycin
- In-vitro study of 12 groups varying tobramycin (0-3g) and vancomycin (0-3g) in Palacos R cement over 28 days
- The highest antibiotic loading did NOT yield the best elution
- 3g tobramycin plus 2g vancomycin gave the greatest cumulative release but significantly reduced compressive strength and increased porosity
- Tobramycin eluted more effectively than vancomycin from the cement
Diagnosis and management of prosthetic joint infection: clinical practice guidelines by the Infectious Diseases Society of America (IDSA)
- Comprehensive evidence- and opinion-based guideline on diagnosis and management of PJI
- Defines the roles of DAIR, one- and two-stage exchange, resection arthroplasty and amputation
- Endorses two-stage exchange with an antibiotic-impregnated spacer for chronic PJI
- Recommends 4-6 weeks of pathogen-directed IV (or highly bioavailable oral) antibiotics after resection