THE BONE & JOINT JOURNAL 1682 P. S. Corona, M. Vicente, L. Carrera, D. Rodríguez-Pardo, S. Corró From Vall d’Hebron University Hospital, Universitat Autònoma de Barcelona, Barcelona, Spain Correspondence should be sent to S. Corró; email: sebastiacr@gmail.com © 2020 The British Editorial Society of Bone & Joint Surgery doi:10.1302/0301-620X.102B12. BJJ-2020-0792.R1 $2.00 Bone Joint J 2020;102-B(12):1682–1688.  ArthroplAsty Current actual success rate of the two-stage exchange arthroplasty strategy in chronic hip and knee periprosthetic joint infection insights into non-completed second-stage cases Aims the success rates of two-stage revision arthroplasty for infection have evolved since their early description. the implementation of internationally accepted outcome criteria led to the readjustment of such rates. however, patients who do not undergo reimplan- tation are usually set aside from these calculations. the aim of this study was to inves- tigate the outcomes of two-stage revision arthroplasty when considering those who do not undergo reimplantation, and to investigate the characteristics of this subgroup. Methods A retrospective cohort study was conducted. patients with chronic hip or knee peripros- thetic joint infection (pJI) treated with two-stage revision between January 2010 and october 2018, with a minimum follow-up of one year, were included. Variables including demography, morbidity, microbiology, and outcome were collected. the primary endpoint was the eradication of infection. patients who did not undergo reimplantation were analyz- ed in order to characterize this subgroup better. results A total of 162 chronic pJIs were included in the study. After a mean follow-up of 57.3 months (12.1 to 115.7), 18 patients (11.1%) did not undergo reimplantation, due either to medical issues (10), the patient’s choice (4), or death (4). When only considering those who underwent reimplantation, the success rate was 80.6%. however, when those who did not undergo reimplantation were included, the success rate dropped to 71.6%. Ad- vanced age, American Society of Anesthesiologists grade ≥ III, McPherson’s C host, and Gram-negative related pJI were independent risk factors for retention of the spacer. the mortality was higher in the non-reimplanted group. Conclusion the real success rate of two-stage revision may not be as high as previously reported. the exclusion of patients who do not undergo reimplantation resulted in a 9% overes- timation of the success rate in this series. Many comorbidity-related risk factors for re- tention of the spacer were identifed, as well as higher death rates in this group. Efforts should be made to optimize these patients medically in order to increase reimplantation and success rates, while decreasing mortality. Cite this article: Bone Joint J 2020;102-B(12):1682–1688. Introduction periprosthetic joint infection (pJi) represents a devastating complication following arthroplasty. its prevention and treatment are the subjects of much debate and research. nowadays, the most extensive treatment for chronic pJi is the two- stage revision procedure. 1 most studies report success rates of more than 80%, 2–7 with some authors claiming a rate of eradication of infection of nearly 100%. 8–12 however, the true success rate for this strategy remains controversial. such high success rates may be overestimated as a result of two main factors: the lack of a wide implementation of internationally accepted and validated criteria for what can be considered a successful outcome, 2,13–15 and the fact that most