Stage 1 (Explantation): the infected knee prosthesis is removed. All cement, infected tissue, and biofilm are thoroughly debrided. An antibiotic-loaded cement spacer (static block or articulating) is inserted. Multiple tissue samples are taken for culture. IV antibiotics begin. Stage 2 (Reimplantation): after six to twelve weeks of antibiotics, the spacer is removed, the joint is re-debrided, and new revision knee replacement components are implanted. Each stage takes two to three hours.
Two-stage revision is recommended for chronic (established) periprosthetic knee infection — defined as infection present for more than four weeks, or infection with difficult-to-treat organisms (MRSA, fungal). It has the highest infection cure rate of any treatment strategy.
DAIR (for acute infection only — within four weeks). One-stage revision (at specialist centres for selected cases). Long-term antibiotic suppression (accepting persistent infection). Above-knee amputation (last resort for uncontrollable infection). Arthrodesis (knee fusion — a salvage option).
Joint aspiration for microbiology. Full blood tests including inflammatory markers. CT for bone stock. MDT discussion with microbiologists. Planning for both stages. Counselling about the inter-stage period.
Infection cure rate approximately 85–95% with two-stage revision. This is the most reliable method of eradicating chronic prosthetic joint infection. Most patients achieve a well-functioning revision knee replacement.
Inter-stage periodExpected
Six to twelve weeks between stages with limited mobility, an antibiotic spacer, and crutches/frame.
Prolonged antibioticsExpected
IV antibiotics for two to six weeks, then oral for several weeks.
StiffnessCommon
Arthrofibrosis is common, particularly with static spacers.
Functional limitationExpected
Revision knee replacement outcomes are less predictable than primary.
Persistent infectionUncommon
Despite two-stage revision, approximately 5–15% of patients have persistent or recurrent infection.
Spacer complicationsUncommon
Dislocation, fracture, or extrusion of the spacer.
Bone lossExpected
Each revision causes additional bone loss.
Wound complicationsCommon
In previously operated, infected tissue.
Medical complicationsCommon
Many patients are elderly with comorbidities.
Periprosthetic fractureUncommon
During component removal or reimplantation.
AmputationRare
For uncontrollable infection. Very rare.
General or spinal anaesthesia for both stages. The patient may be medically complex.
Stage 1: hospital one to two weeks. PICC line for IV antibiotics. Limited mobility with spacer. Regular blood tests. Stage 2: reimplantation once infection markers normalise and aspiration is negative. Recovery after stage 2 is similar to revision TKR — hospital three to five days, physiotherapy, full recovery six to twelve months.
Twice-weekly blood tests during IV antibiotics. Clinical review every two weeks during inter-stage. Joint aspiration before stage 2. Post-reimplantation: standard revision TKR follow-up.
How long between the two stages?
Typically six to twelve weeks. The timing depends on normalisation of inflammatory markers, clearance of the organism on aspiration, and the patient's overall condition. Rushing to stage 2 before the infection is cleared risks failure.
What is the success rate?
Two-stage revision has the highest published cure rate — approximately 85–95%. The inter-stage period is challenging but gives the best chance of a long-term, infection-free knee replacement.
What if the infection comes back after reimplantation?
Options include repeat two-stage revision, long-term antibiotic suppression, knee fusion (arthrodesis), or, as a last resort, above-knee amputation. Fortunately, with careful technique and appropriate antibiotics, re-infection after two-stage revision is uncommon.