ONE-STAGE VERSUS 1.5-STAGE REVISION FOR PERIPROSTHETIC JOINT INFECTION: A SYSTEMATIC REVIEW AND META-ANALYSIS

Introduction & Aim The 1.5-stage revision strategy — implantation of an antibiotic-loaded functional construct without a planned second stage — has gained traction as an intermediate alternative to formal one-stage exchange in periprosthetic joint infection (PJI). Its theoretical appeal lies in sparing patients a second surgery while managing cases deemed unsuitable for single-stage revision. However, if 1.5-stage revision shares the same procedural logic as one-stage exchange — potentially a single definitive implantation — it must be held to the same clinical standard. Existing literature has compared 1.5-stage predominantly against two-stage revision, obscuring this critical question. This systematic review and meta-analysis is the first to directly compare one-stage and 1.5-stage revision, evaluating whether the latter offers any clinical advantage over the former. Methods Following PRISMA guidelines, PubMed, EMBASE, and Scopus were searched for studies comparing one-stage and 1.5-stage TKA revisions. Primary outcomes included infection relapse, reintervention rates, and time-to-failure. Results Sixty-seven studies (59 one-stage, 8 1.5-stage) involving 1,145 patients were included. Indication criteria for 1.5-stage were not broader than those for one-stage; both shared major contraindications like massive bone loss and MDR organisms. 1.5-stage was predominantly reserved for elderly patients with high comorbidities. The pooled infection relapse rate was 8.5%, with no significant difference between one-stage and 1.5-stage procedures (8.5% vs. 11.2%; p=0.345). Similarly, overall reintervention rates showed no significant difference (16.6% vs. 18.5%; p=0.653). Crucially, 1.5-stage studies had significantly shorter mean follow-up (2.89 vs. 4.84 years; p=0.021), yet showed a trend toward earlier reintervention (1.45 vs. 2.52 years; p=0.087) and shorter time to reinfection (0.96 vs. 1.79 years; p=0.312). Conclusions This meta-analysis found no clinical advantage of 1.5-stage over one-stage revision for PJI. Despite shorter follow-up, the 1.5-stage group showed numerically higher failure rates and earlier time to failure. Since the 1.5-stage does not expand patient eligibility and involves inherent potential for a second surgery without outperforming a single-procedure strategy, it cannot be supported as a primary treatment option. It should be regarded as a salvage strategy for selected patients rather than a reliable alternative to one-stage revision.