BackgroundPeriprosthetic joint infection is a serious disease with severe consequences for the patient's life. It is not known whether one-stage or two-stage replacement arthroplasty is superior. So far, there have been no studies on short-term complications between both surgical procedures. Therefore, we performed a retrospective study aiming to determine: 1) Does two-stage septic exchange arthroplasty have a higher short-term complication rate than one-stage? 2) Is there a difference in length of hospital stay and the in-hospital mortality rate between two- and one-stage septic exchange arthroplasty? HypothesisTwo-stage septic exchange arthroplasty has a higher short-term complication rate than one-stage. Patients and methodsRetrospectively 429 patients who underwent a one- or two stage revision arthroplasty (288 hips and 141 knees) due to chronic PJI between January 2015 and December 2016 were recruited (one-stage: n=385, two-stage: n=44). Differences in postoperative complications, surgical therapy, ASA, Charlson Comorbidity Index (CCI), length of hospital, need for plastic surgery, pathogen, in-hospital morbidity and in-hospital mortality were compared using multiple logistic and Poisson regression. Regarding comorbidities, age, gender and BMI the groups were comparable. ResultsIt was 3.5 times more likely to suffer from a medical complication if a two stage septic exchange was performed (OR 3.465, (95 % CI: 2.573 – 4.358) (p<0.01)). In medical complications the two-stage group showed significantly more events (two-stage: 9 of 44=20.5 %; one-stage: 30 of 385=7.8 % (p=0.013)). The one-stage group showed more (not significant) nerve palsies after hip septic exchange. There was no difference in mortality between the groups (two-stage: 1/44=2.3 %; one-stage: 3/385=0.8 % (p=0.882)), the overall mortality was 0.93 %. The duration of hospital stay was 23.9±19 days for the one-stage and 42.2±17.7 days for the two-stage group (p<0.001). ConclusionWe found that it is more likely to develop a medical complication after two-stage septic revision arthroplasty. There was no difference in overall surgical complications between the two surgical approaches. There was no difference in short-term mortality between the two techniques. Level of evidenceIII, retrospective case control study.