After the infected prosthesis is removed and the joint is thoroughly debrided, a spacer is fashioned intra-operatively from antibiotic-loaded bone cement (polymethylmethacrylate — PMMA). Hip spacers are typically articulating (shaped like a prosthesis to allow walking). Knee spacers may be static (block) or articulating (shaped like a knee replacement). High-dose antibiotics (vancomycin, gentamicin, or organism-specific) are mixed into the cement. The spacer is inserted and the wound closed. The operation takes one and a half to three hours.
Spacers are the standard first stage of two-stage revision for chronic prosthetic joint infection — the most reliable method of eradicating established PJI with approximately 85–95% infection cure rates.
One-stage revision (at specialist centres for selected cases), DAIR (for acute infections only), long-term antibiotic suppression (accepting persistent infection), resection arthroplasty (Girdlestone — leaving no implant), or amputation (last resort).
Joint aspiration for microbiology. Blood inflammatory markers. CT to assess bone stock. MDT discussion with microbiologists. Planning the revision implant for the second stage.
Eradication of infection in approximately 85–95% of patients with two-stage revision. The spacer delivers high local antibiotic concentrations directly to the infected tissue. Articulating spacers allow limited walking during the inter-stage period.
Limited mobilityExpected
Walking is restricted with a spacer — crutches or a frame are needed.
Spacer dislocationCommon
Particularly hip spacers. May need repositioning.
Inter-stage periodExpected
Four to twelve weeks between stages. This is a challenging period.
Prolonged antibioticsExpected
IV antibiotics for two to six weeks, then oral for several weeks.
Persistent infectionUncommon
The infection may not be fully eradicated despite the spacer. Risk approximately 5–15%.
Spacer fractureUncommon
The cement spacer may break, particularly in heavier patients.
Bone lossCommon
Cement removal at second stage may cause additional bone loss.
Wound complicationsCommon
In previously operated, infected tissue.
Medical complicationsCommon
Many patients with PJI have significant comorbidities.
Antibiotic toxicityUncommon
High-dose local and systemic antibiotics carry toxicity risks (renal, ototoxicity).
General or spinal anaesthesia. The patient may be medically complex.
Hospital one to two weeks. IV antibiotics via PICC line for two to six weeks. Regular blood tests (CRP, ESR, renal function, antibiotic levels). Limited weight-bearing with aids. Joint aspiration before second stage to confirm infection clearance. Second stage (reimplantation) at six to twelve weeks.
Regular blood tests twice weekly during IV antibiotics. Clinical review at two, four, and six weeks. Joint aspiration before second stage. MDT review to confirm readiness for reimplantation.
How long between first and second stage?
Typically six to twelve weeks. During this time, antibiotics are given and infection markers are monitored. The second stage is only performed when clinical and laboratory evidence confirms infection clearance.
What is the success rate?
Two-stage revision has the highest infection cure rate of any method — approximately 85–95%. The inter-stage period is challenging but gives the best chance of a permanent, infection-free joint replacement.