Open debridement, irrigation with implant retention and antibiotic treatment (DAIR) is an accepted approach for early prosthetic joint infections (PJI). Our aim was to design a score to predict patients with a higher risk of failure.

From 1999 to 2014 early (<90 days) PJIs without signs of loosening of the prosthesis were treated with DAIR and were prospectively collected and retrospectively reviewed. The primary end-point was early failure defined as: 1) the need of an unscheduled surgery, 2) death-related infection within the first 60 days after debridement or 3) the need for suppressive antibiotic treatment. A score was built-up according to the logistic regression coefficients of variables available before debridement.

A total of 222 patients met the inclusion criteria. The most frequently isolated microorganisms were coagulase-negative staphylococci (95 cases, 42.8%) and Staphylococcus aureus (81 cases, 36.5%). Fifty-two (23.4%) cases failed. Independent predictors of failure were: chronic renal failure (OR:5.92, 95%CI:1.47–23.85), liver cirrhosis (OR:4.46, 95%CI:1.15–17.24), revision surgery (OR:4.34, 95%CI:1.34–14.04) or femoral neck fracture (OR:4.39, 95%CI:1.16–16.62) compared to primary arthroplasty, CRP >11.5 mg/dL (OR:12.308, 95%CI:4.56–33.19), cemented prosthesis (OR:8.71, 95%CI:1.95–38.97) and when all intraoperative cultures were positive (OR:6.30, 95%CI:1.84–21.53). Furthermore, CRP showed a direct relationship with the percentage of positive cultures (Linear equation, R2=0,046, P=0.002) and an inverse association with the time between the debridement and failure (Logarithmic equation, R2=0.179, P=0.003). A score for predicting the risk of failure was done using pre-operative factors (KLIC-score, figure 1) and it ranged between 0–9.5 points. Patients with a score ≤2, >2–3.5, 4–5, >5–6.5 and ≥7 had a failure rate of 4.5%, 19.4%, 55%, 71.4% and 100%, respectively.

The KLIC-score was highly predictive of early failure after debridement. In the future, it would be necessary to validate our score using cohorts from other institutions.

Two-stage revision surgery is the current gold standard for treating prosthetic joint infections (PJI). Between the first and the second stage gentamicin-loaded (G) spacers are widely used but the rate of gentamicin resistant staphylococci is increasing. The potential benefit of vancomycin + gentamicin-loaded (V/G) spacers has not yet been evaluated. The aim of our study was to compare the microbiological eradication and infection control rates in PJI treated with G- or V/G-spacers.

147 PJIs treated in our institution were retrospectively reviewed. From 2003 to 2009 G-spacers (Tecres®) were used (group G) and from 2010 to 2013 V/G-spacers (Group V/G). Gender, age, body mass index (BMI), co-morbidities, ASA score, type of infection, microorganisms isolated in the first and second stages, time between stages, infection outcome at last visit were collected. The 2 main outcome variables were microbiological eradication in the second stage (≤1 positive culture out of 6) and infection control after the second stage. Univariate and multivariate analysis were performed using SPSS®.

There were 83 patients in group G and 63 in group V/G. The mean (SD) age was 71.5 (10.3) years and 54% were female. Groups were similar in gender, age, BMI, ASA score, time with spacer, microorganism isolated in the first stage, or type of infection (acute or chronic) (p>0.05). The presence of ≥2 positive cultures in the second stage was significantly higher in group G (23.2%) than in group V/G (6.7%, P<0.05). Logistic regression model identified polymicrobial infections (OR: 4.26, CI95%: 1.44–12.64) and the use of G-spacers (OR: 5.88, CI95%: 1.60–21.74) as independent predictors of failure in microbiological eradication. The global rate of infection control was 75% after a mean (SD) follow-up of 56 (32) months. Infection control was higher in chronic than acute PJI (83.6% vs 59.6%, P<0.05), when cultures during second stage were negative (81.5%) vs positive (61%, P<0.05), and there was a trend towards a higher control rate when V/G-spacers (82%) vs G-spacers (69.5%) were used (P=0.09). Multivariate analysis identified chronic PJI (OR: 5.43, CI95%: 2.20–13.51) and, at the limit of significance, the use of V/G spacers (OR: 2.36, CI95%: 0.97–5.71) as predictors of infection control.

Vancomycin loaded spacers were significantly associated with a higher microbiological eradication and there was a trend towards a higher infection control than gentamicin loaded spacers.

Early prosthetic joint infections (PJI) are managed with debridement, implant retention and antibiotics (DAIR). Our aim was to evaluate risk factors for failure after stopping antibiotic treatment.

From 1999 to 2013 early PJIs managed with DAIR were prospectively collected and retrospectively reviewed. The main variables potentially associated with outcome were gathered and the minimum follow-up was 2 years. Primary endpoint was implant removal or the need of reintroducing antibiotic treatment due to failure.

A total of 143 patients met the inclusion criteria. The failure rate after a median (IQR) duration of oral antibiotic treatment of 69 (45–95) days was 11.8%. In 92 cases PJI was due to gram-positive (GP) microorganisms, in 21 due to gram-negatives (GN) and 30 had a polymicrobial infection. In GP infections, combination of rifampin with linezolid, cotrimoxazole or clindamycin was associated with a higher failure rate (27.8%, P=0.026) in comparison to patients receiving a combination of rifampin with levofloxacin, ciprofloxacin or amoxicillin (8.3%) or monotherapy with linezolid or cotrimoxazole (0%) (Figure 1). Among patients with a GN infection, the use of fluoroquinolones was associated with a lower failure rate (7.1% vs 37.5%, P=0.044). Duration of antibiotic treatment was not associated with failure.

The only factor associated with failure was the oral antibiotic selection, but not the duration of treatment. Linezolid, cotrimoxazole and clindamycin but not levofloxacin serum concentrations are reduced by rifampin; a fact that could explain our findings. Further studies monitoring serum concentration could help to improve the efficacy of these antibiotics when combining with rifampin.

Stored red blood cells (RBCs) undergo a variety of changes that impair their post-transfusion viability, but the detrimental effect of such lesion at the clinical level is a matter of debate (1) and there is no data about the incidence of postoperative infection, a complication frequently associated with transfusion of stored RBCs (2).

We reviewed 9906 patients who underwent a primary or revision arthroplasty between January 2000 and December 2012. Of these, 1153 (11.6%) received transfusion during surgery or within the first 6h after surgery (early transfusion, ET) and 920 (9.3%) received transfusion only between 24 and 96 hours after surgery (late transfusion, LT). Primary end-point was prosthetic joint infection (PJI) within the first year. Demographics, joint, type of surgery, duration of surgery, number and length of storage of transfused RBCs were collected. Ethical Committee approved the study.

The median age was 74.9 (IQR:68.3–80.1) years and 1546 (74.6%) were female. There were 914 (44.1%) hip and 1117 (53.9%) knee arthroplasties and 428 (20.6%) were revision surgeries. The median duration of surgery was 105 (IQR:80–145) minutes. A total of 100 (4.8%) patients had a PJI. Figure 1 shows the PJI rate according to the number of RBC units transfused and the proportion of such units that had been stored for more than 14 days, both in the ET-group (Fig. 1A) and the LT-group (Fig. 1B). In the ET-group, the fact that >50% of transfused RBCs had been stored >14 days was an independent predictor of PJI (OR:2.50, 95%CI:1.44–4.33, Hosmer-Lemeshow test P=0.972).

Stored RBC occlude the microcirculation (1), thereby precluding a good oxygenation of the surgical wound and the arrival of leukocytes and prophylactic antibiotics. Both factors are involved in the progression from wound bacterial contamination to wound infection and are particularly operative in the few hours following surgery (5). It is biologically plausible that transfusion of old RBC in this early, critical period results in more wound infections as compared to RBCs transfused later.