# One-Stage versus Two-Stage Exchange > One-stage versus two-stage exchange for periprosthetic infection for NEET-PG Orthopaedics: selection criteria, success rates, organisms and Indian practice. - Canonical URL: https://prepelephant.com/topics/neet-pg/orthopaedics/one-stage-two-stage-exchange - Exam / course: NEET-PG · Subject: Orthopaedics - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "One-Stage versus Two-Stage Exchange", PrepElephant, https://prepelephant.com/topics/neet-pg/orthopaedics/one-stage-two-stage-exchange ## Direct answer Two operations or one — that is the strategic choice in revising an infected joint replacement. The two-stage exchange remains the taught default: debride radically and remove all implants, place an antibiotic cement spacer, run targeted antibiotics for two to six weeks, then reimplant once markers fall — with success commonly quoted at 85-90 percent. Single-stage exchange — debridement and new implants in the same anaesthetic — now has randomised support in carefully selected knees, matching two-stage results when its criteria are met: no sinus tract, adequate soft tissues, a known susceptible organism, no difficult pathogens. In Indian practice the single-stage option has a hard economic edge, because the patient who vanishes between two admissions is a real failure mode. ## What you must remember - **Two-stage protocol:** stage 1 — radical debridement, excise all implants and cement, antibiotic-loaded cement spacer, targeted systemic antibiotics for two to six weeks; stage 2 — reimplant when infection markers fall and the joint is clinically quiet; success commonly quoted at 85-90 percent or better. - **Single-stage protocol:** radical debridement with removal and reimplantation in one sitting, antibiotic-loaded cement (fixation-grade or higher dosing), same-anaesthetic new implants; randomised evidence now supports it in selected knee infections, with European centres leading adoption. - **Selection criteria for single-stage (the examinable list):** no sinus tract; adequate soft-tissue envelope; organism identified preoperatively or highly predictable and susceptible to cement-available antibiotics; no difficult organisms (fungi, mycobacteria, resistant gram-negatives, MRSA by many teams' policies); no major immunocompromise; an experienced team with reliable microbiology. - **Difficult organisms:** fungi, atypical mycobacteria, Enterococcus, multidrug-resistant gram-negatives and culture-negative cases push toward two-stage, where the organism can be restudied between stages. - **Two-stage advantages:** a second look with fresh cultures, the option to re-aspirate before reimplantation, and flexibility when preoperative workup was incomplete; disadvantages — two anaesthetics and admissions, spacer morbidity (pain, instability, bone loss), higher cost, longer disability. - **Single-stage advantages:** one admission, faster rehabilitation, dramatically lower cost — decisive where a second admission may never happen; the price is that there is no second chance to change strategy. - **Readiness for stage 2:** falling CRP trend, no sinus, stable spacer, negative aspirate if performed — trends beat single numbers, and absolute CRP cutoffs vary between schools. - **Indian practice reality:** the lost-between-stages patient — discharged with a spacer and never returning — makes single-stage attractive, but its safety rests on microbiology depth: cultures held long enough, sensitivities reliable, cement antibiotics available; centres without that infrastructure should default to two-stage. ## Criteria that decide the single stage Run two patients side by side. A 66-year-old's knee grows methicillin-sensitive Staphylococcus aureus on preoperative aspiration; skin is clean, the sinus absent, the patient fit. Every single-stage criterion ticks: known organism susceptible to cefazolin that works in cement and veins, intact soft tissues, experienced team — debride, exchange, reimplant in one anaesthetic, and the patient wakes with a new knee and one hospital bill. The second arrives with a discharging sinus and a wound that has broken down twice; cultures are pending and a resistant gram-negative is suspected. Sinus plus unknown, possibly resistant organism — two criteria already fail, and the answer is two-stage: debride, spacer, targeted therapy, then reimplant when the markers fall and the organism has been cornered. The joint call — surgeon and microbiologist at the same table — is what the criteria were written for. ## Two operations or one? The MCQ still scores "gold standard — two-stage exchange," and that answer remains safe; the viva rewards the nuance that single-stage exchange, correctly selected, now carries randomised evidence in knees. The sharper trap is comparing success rates as if the populations were identical: single-stage patients are pre-selected — clean skin, known bugs, fit bodies — so equal percentages flatter the single stage and ignore selection bias. The Indian turn deserves stating aloud: a plan assuming a second admission must ask whether the patient can afford one, because a defaulting patient with a spacer is a worse outcome than any difference the trials measure — which is why the criteria, not the dogma, decide. ## Frequently asked questions ### What is the two-stage exchange protocol? Radical debridement with removal of all implants, an antibiotic cement spacer, targeted antibiotics for two to six weeks, and reimplantation once infection markers fall and the joint is clinically quiet. ### What criteria allow a single-stage exchange? No sinus tract, adequate soft tissues, a preoperatively known and susceptible organism, no difficult pathogens, no major immunocompromise, and an experienced team with reliable microbiology. ### Which organisms generally force a two-stage approach? Fungi, mycobacteria, enterococci, multidrug-resistant gram-negatives and culture-negative cases — any pathogen that needs restudying between stages. ### Why are single-stage success rates hard to compare with two-stage? Patient selection differs — single-stage candidates are pre-filtered for clean soft tissues and treatable organisms, so equal percentages do not mean equal difficulty. ### What signals readiness for the second stage of a two-stage exchange? A falling CRP trend, no sinus tract, a stable spacer and, where performed, a negative aspiration — trends matter more than any single number.