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.

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.

Introduction: Although the influence of preoperative nutritional status on short term outcome in arthroplasty is well known, its relationship with early prosthetic joint infection (EPJI) in total knee replacement remains unclear.

Aim: Our aim was to assess the effect of preoperative nutritional status on patients who went on to present with EPJI following total knee replacement surgery. This assessment was based on preoperative blood tests and anthropometric measurements.

Methods: A total of 213 patients undergoing total knee replacement between December 2007 and May 2008 were included in the study. Patients with rheumatoid arthritis were excluded. For each patient we pre-operatively checked haemoglobin level, CRP, ESR, total lymphocyte and protein count, albumin and pre-albumin concentration and triglicerids, cholesterol and creatinine levels. Triceps skindfold and arm/muscle circumference were measured the day before surgery. The body mass index was calculated based on the information contained in the anaesthetic chart. We also collected information about co-morbidities such as Diabetes, High blood pressure, ASA grading, age and gender. Information about early infections, both superficial and deep, was collected. A descriptive statistical analysis and logistic regression models approach for independent risk factors were performed.

Results: The mean age was 71.5 years. There were 162 female and 51 male. Eleven patients (5.16%) had early wound infection: 5 deep EPJI and 6 superficial. Neither co-morbidities nor preoperatively laboratory test except CRP (OR 1.44, p=0.03) were associated with a high early infection risk. However, there was an inversely proportional relationship between EPJI and anthropometric measurements: triceps skindfold (OR 0.9 p=0.011) and fat area (FA) (OR 0.94, p=0.01).

Conclusion: A low triceps skindfold and FA were associated with an increment of risk of EPJI after a knee replacement. Although the relationship between some laboratory test as pre-albumin and lymphocyte account and wound healing and postoperatively complications is well known, we didn’t find it with EPJI in our group except for CRP levels.

Introduction: The histology of prosthetic tissue is a gold standard for the diagnosis of prosthetic joint infection. However, the specificity and sensitivity of histology has never been 100% and this could be due to several causes. A possible cause for inconsistencies in histological results could be the type of specimen submitted to laboratory. The majority of authors obtain specimens from pseudocapsule, interface membrane and any tissue area suspicious of infection.

Aim: The objective of our study was to elucidate which is the most accurate specimen for histological diagnosis of prosthetic joint infection.

Methods: Prospective study including all revision arthroplasties performed in Hospital Clinic of Barcelona (Spain) from January 2007 to June of 2009. Specimens from pseudocapsule and from interface membrane were obtained from each patient. Definitive diagnosis of infection was considered when ≥2 cultures were positive for the same microorganism or the presence of pus around the prosthesis. Patients were classified in two groups:

patients submitted to hip revision arthroplasty due to an aseptic loosening in whom cultures (at least 5) obtained during surgery were negative and

Results: A total of 69 revisions were included in the study; 57 were classified in the group A and 12 were classified in the group B. The percentage of positive interface membrane histology in patients with prosthetic joint infection (group B) was significantly higher than the percentage of positive pseudocapsule histology (83.3% vs 41.6%, p=0.04, Fisher exact test).

Conclusion: The results suggest that the best specimen of periprosthetic soft tissue for histological study to diagnose the chronic periprosthetic infection in a revision total hip arthroplasty is the periprosthetic interface membrane.

Introduction: The most important cause of prosthetic joint infection (PJI) is the contamination of the wound during the surgery. Nowadays, it doesn’t exist any image or laboratory test for early detection of prosthesis with a higher risk of developing a PJI.

Aim: The primary aim was to evaluate the usefulness of different intraoperative samples during the surgery of implantation of a primary hip arthroplasty (PHA) as a predicting factor of PJI.

Methods: A prospective cohort study was performed. All patients (n= 278) who underwent a PHA from January ’06 to November ’08 were included. Three samples: a piece of articular capsule (TS), a swab (S) and synovial fluid (SF) inoculated into blood flask were taken in each patient during the first 45 minutes of surgery. Other possible risk factors of PJI like age, sex, ASA, comorbidity and surgical time were registered.

Results: A total of 278 patients were included. 30 cultures (8 SF, 13 TS and 9 S) were positive in 29 patients. The most frequent microorganism isolated was Coagulase-negative staphylococci (CNS) (66.6%). The rate of PJI (early and late) in the subgroup of patients with positive intraoperative cultures for CNS was 25% while in the subgroup with all negative cultures was 5.2% (RR=4.8; p=0.007). Other factors significantly associated with a higher rate of PJI in the univariate analysis were: ASA III (RR=9.12; p=0.02), cardiopathy (RR= 2.82; p=0.04), obstructive pulmonary chronic disease (RR=5; p=0.02) and rheumatoid arthritis (RR=4.16; p=0.04). Multivariate analysis found ASA III (Odds ratio 10.9; CI 95% 1.27–94.6; p=0.02) and a positive intraoperative culture for CNS (Odds ratio 5.92; CI 95%=1.8–19.85; p=0.03) as independent risk factors for PJI.

Conclusion: Positive intraoperative culture for CNS during PHA was independently associated with the development of PJI.

Exchange of infected implant using antibiotic-impregnated cement is the treatment of choice in prosthetic joint infection (PJI). We presented our experience using one or two-stage exchange with uncemented implants.

From January 2000 to June 2006 patients with a PJI that were treated with one or two-stage exchange with uncemented implants, were prospectively followed up. The treatment protocol consisted of radical excision of devitalized tissue and of maintaining a high serum antibiotic concentration during surgery followed by systemic antibiotic administration according to the microbiology results. Only patients with ≥6 months of follow-up were included. Good evolution was considered when symptoms and signs of infection disappeared and the C-Reactive Protein was normal.

Forty-two patients were included in the study, of whom 25 were male. The mean age was 70 years. The most common symptom was pain (100%) and radiological signs of prosthesis loosening were present in 36 cases (85.7%). Histology was positive in 32 patients (76.2%). Coagulase-negative staphylococci was the most common microorganism (23 cases) followed by S. aureus (5 cases). One-stage exchange was performed in 18 patients, and the long stem component was always uncemented. In one case an acute infection after the arthroplasty obligated to perform an open debridément without implant removal. After a mean follow-up of 31 months (range: 6–84) all patients had a good evolution. In 24 cases a 2-stage exchange with a joint spacer with gentamycin (Spacer-G) was performed. In all cases the definitive arthroplasty was performed using an uncemented long stem. Good evolution was documented in all but one case with persistent infection due to S. aureus after a mean follow-up of 19 months (range: 12–48).

Our results suggest that uncemented arthroplasty following a protocol based on radical debridément and systemic antibiotic therapy during and after surgery is a useful approach in PJI.

In primary total knee arthroplasty (TKA) performed under ischemia the antibiotic prophylaxis is administered 15’ before inflating the tourniquet. The infection rate in TKA is higher than in hip arthroplasty. We hypothesise that ischemia could impair the efficacy of the antibiotic. The objective of our study was to compare the effectiveness of two schedules of antibiotic administration.

We conducted a randomised and a double blind study. Patients were assigned to receive placebo 15’ before inflating tourniquet and cefuroxim 1.5 g 10’ before releasing the tourniquet (experimental arm) or cefuroxim 1.5 g 15’ before inflating tourniquet and placebo 15’ before releasing tourniquet (standard arm). In both arms cefuroxime 1.5 g was administered 6 hours after finishing surgery. The variables gathered were: age, sex, indication for TKA, co-morbidity, ASA score, duration of the operation, number of blood transfusions, days of hospitalisation and number of surgical site infections after 3 months of surgery. Categorical variables were compared using the χ² test or the Fisher exact test and quantitative variables using Student-t test.

Nine hundred and eight patients were randomised and 466 and 442 patients were allocated to experimental and standard arms respectively. Both groups were similar and there were no differences in deep and superficial infection rates, 1.39% and 4.18% for experimental arm and 3.39% and 3.17% for standard arm (p> 0.05). The experimental arm had a lower global and deep infection rate than the standard arm when the length of surgery was lower than the 75th percentile (global: 4.03 vs 7.93%, p=0.04, deep: 1.72% vs 4.44%, p=0.07).

The administration of antibiotic prophylaxis 10’ before releasing the tourniquet decreases the surgical site infection rate when the duration of surgery is lower than the 75th percentile.

Intraoperative histology has a high specificity and sensitivity to identify prosthetic joint infection. However, the usefulness of this technique according to the type of microorganism isolated in the periprosthetic tissue has not previously been studied.

Frozen sections and cultures from periprosthetic tissue of 38 revision arthroplasties performed due to prosthetic joint infection were retrospectively reviewed. Frozen sections were evaluated according to Mirras’ criteria (adapted by Feldman). Culture was considered positive when the same microorganism was isolated in at least 2 samples or the presence of pus around the prosthesis.

Coagulase-negative staphylococci (CNS) was the aetiology in 13 cases, Gram-negative bacilli in 8, S. aureus in 7, Candida sp and Peptococcus sp in 2 and Enterococcus sp, S.pneumoniae and in 1 case each one. No microorganism was isolated in 4 cases. Frozen sections revealed more than 5 neuthrophils per high power field (forty times) in at least five fields in all cases except in 2 out of 13 caused by CNS (15.3%). A revision of the articles that provided information on the aetiology and the histology supports the findings of our study.

In conclusion, frozen section using Feldman’s criteria had a 15.3% of false negative cases when CNS was the aetiology of the prosthetic joint infection.