Eduard Tornero

Prosthetic joint infections due to Staphylococcus aureus and coagulase-negative staphylococci

Purposes To evaluate the specific characteristics, outcome, and predictors of failure of prosthetic joint infections (PJI) due to S. aureus and coagulase-negative staphylococci (CNS) treated with open debridement and retention of the implant. Methods PJI due to S. aureus or CNS prospectively registered in a database from 1999 to 2009 were retrospectively reviewed. During the study period, 106 patients met the inclusion criteria. The mean follow-up period was 3.8 years and for at least 2 years in all patients. The failure rate was 23.6% (25 out of 106). The only variable significantly associated with failure in the global cohort was polymicrobial infection (38.7% vs. 17.3%, p = 0.024). Fifty-seven (53.8%) patients had an infection due to S. aureus and 49 (46.2%) due to CNS. Among S. aureus infections, 95% corresponded to primary arthroplasties while 98% of PJIs due to CNS were after revision arthroplasties (p<0.001). C-reactive protein was significantly higher in PJI due to S. aureus (9.5 mg/dl vs. 4.9 mg/dl, p = 0.007). The rate of methicillin-resistance (8.8% vs. 59.2%, p<0.001) and fluoroquinolone-resistance (15.8% vs. 34.7%, p = 0.005) was significantly higher in CNS infections. The global failure rate was higher in S. aureus infections (28% vs. 18.3. p = 0.26). In S. aureus infections, patients diagnosed within the first 15 days after joint arthroplasty (p = 0.031) and with bacteremia (p = 0.046) had poor prognosis. In CNS infections only the location of the prosthesis (knee 27.6% vs. hip 5%, p = 0.045) was associated with failure. Conclusions PJIs due to S. aureus were mainly in primary arthroplasties; they had a higher inflammatory response; and the strains were more susceptible to fluoroquinolones and methicillin than CNS infections. S. aureus infections had a higher failure rate than CNS infections, however, the difference was not statistically significant. There were few factors associated with failure and they were different in S. aureus and CNS infections.

Efficacy of debridement in hematogenous and early post-surgical prosthetic joint infections.

Purposes To review patients with a hematogenous and early post-surgical prosthetic joint infection (PJI) due to S. aureus treated with debridement and retention of the implant and to compare their clinical characteristics and outcome. Methods From January 2000 all patients with a prosthetic joint infection treated in a single-center were prospectively registered and followed-up. All potentially variables associated with outcome were recorded. For the present study, cases with a hematogenous or early post-surgical PJI due to S. aureus treated with debridement and at least 2 years of follow-up were reviewed. Cox regression model to identify factors associated with outcome were applied. Results 12 hematogenous and 53 early post-surgical PJI due to S. aureus were included. Number of patients presenting with fever, leucocyte count, C-reactive protein concentration, and the number of bacteremic patients were significantly higher in hematogenous infections while the number of polymicrobial infections was lower in hematogenous than in early post-surgical infections. The global failure rate in hematogenous and early post-surgical PJI was 58.7% and 24.5%, respectively (p=0.02). The Cox regression model identified hematogenous infections (OR: 2.57, CI95%: 1.02–6.51, p=0.04) and the need of a second debridement (OR: 4.61, CI95%: 1.86–11.4, p=0.001) as independent predictors of failure. Conclusion Hematogenous infections were monomicrobial and had more severe symptoms and signs of infection than early post-surgical PJI. Hematogenous PJI due to S. aureus, using debridement with implant retention, had a worse outcome than early post-surgical infections.

Relationship between intraoperative cultures during hip arthroplasty, obesity, and the risk of early prosthetic joint infection: A prospective study of 428 patients

Purpose To evaluate the relationship between intraoperative cultures during hip arthroplasty, the different patient characteristics, and the risk of developing a prosthetic joint infection (PJI). Methods A prospective observational study was performed. Patients who underwent elective THA from March 2007 to March of 2011 were included. Three samples were taken just after arthrotomy: synovial fluid inoculated into blood culture flasks (SF), a tissue sample (TS), and a swab of periprosthetic tissue (S). Patients received standard antibiotic prophylaxis. The PJI rate within the first 3 months after arthroplasty was recorded. Results 402 prostheses were included in the study. Contamination rate of synovial fluid was 10.2%. The most frequent isolated microorganism was coagulase-negative staphylococci (CoNS) (32 out of 41). Body mass index (BMI) was the only host characteristic associated with positive intraoperative culture (p=0.009). The PJI rate was 3.7%. Variables associated with PJI in the univariate and multivariate analysis were: age ≥67 years (p=0.012 OR: 5.35 (1.45–19.81); CI95%) and a BMI ≥35 (p=0.002, OR: 7.7 (2.12–27.85) CI95%). PJI rate among patients with BMI<35 with negative and positive intraoperative cultures was 3% and 2.7%, respectively, however, the rate among patients with BMI ≥ 35 was 15% and 25%, respectively. Conclusion A BMI ≥35 was associated with a higher risk of positive intraoperative culture during hip arthroplasty. In addition, a BMI ≥35 was independently associated with a high risk of PJI and the highest rate was documented among obese patients with positive intraoperative cultures.

Length of Storage of Transfused Red Blood Cells and Risk of Prosthetic Joint Infection After Primary Knee Arthroplasty

The aim of our study was to determine the potential influence of blood transfusion and the length of storage of packed red blood cells (RBC) on prosthetic joint infection after primary knee arthroplasty. From November 2007 to November 2009, all variables potentially associated with deep infection were registered in 1331 consecutive patients who underwent total knee arthroplasty. Infection was diagnosed in 32 (2.4%) patients. After adjusting for important variables, blood transfusion with RBCs stored >14days was the strongest predictive factor for prosthetic joint infection within 90days after primary knee arthroplasty (OR: 5.9, 95% CI: 2.6-13.2, P < 0.001). Blood saving techniques are desirable to reduce perioperative blood transfusion.

Importance of selection and duration of antibiotic regimen in prosthetic joint infections treated with debridement and implant retention.

OBJECTIVES Early prosthetic joint infections (PJIs) are managed with debridement, implant retention and antibiotics (DAIR). Our aim was to evaluate risk factors for failure after stopping antibiotic treatment. METHODS 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. For the present study, only patients who were in remission after one debridement and without long-term antibiotic suppression were included. The primary endpoint was implant removal or the need to reintroduce antibiotic treatment due to failure. RESULTS One-hundred-and-forty-three patients met the inclusion criteria. The failure rate after a median duration of oral antibiotic treatment of 69 days (IQR 45-95 days) was 11.8%. In 92 cases, PJI was due to Gram-positive microorganisms, in 21 cases PJI was due to Gram-negative microorganisms and in 30 cases PJI was due to a polymicrobial infection with both Gram-positive and Gram-negative microorganisms. In Gram-positive infections, rifampicin administered in combination with linezolid, co-trimoxazole or clindamycin was associated with a higher failure rate (27.8%, P = 0.026) than that in patients receiving a combination of rifampicin with levofloxacin, ciprofloxacin or amoxicillin (8.3%) or monotherapy with linezolid or co-trimoxazole (0%). Among patients with a Gram-negative infection, the use of fluoroquinolones was associated with a lower failure rate (7.1% versus 37.5%, P = 0.044). CONCLUSIONS The only factor associated with failure was the oral antibiotic selection, not the duration of treatment. Linezolid, co-trimoxazole and clindamycin, but not levofloxacin, serum concentrations are reduced by rifampicin; a fact that could explain our findings. Further studies monitoring serum concentration could help to improve the efficacy of these antibiotics when administered in combination with rifampicin.

Clinical experience with linezolid for the treatment of orthopaedic implant infections

Gram-positive cocci are commonly isolated in orthopaedic implant infections and their resistance to β-lactams and fluoroquinolones is increasing. The high oral bioavailability of linezolid makes it an attractive oral alternative to glycopeptides and its use has increased in the last decade. To evaluate experience with linezolid in orthopaedic implant infections a systematic review of the literature available in English was undertaken. Only those articles describing series of ≥10 patients with acute or chronic orthopaedic implant infections treated with linezolid and with a clear definition of diagnosis and outcome were selected. A total of 293 patients (79.9% had prosthetic joint infections) were analysed in the 10 articles included. The overall remission rate with at least 3 months of follow-up was 79.9%, depending on whether the implant was removed or not (94% versus 69.9%). The addition of rifampicin was described in only two articles and no significant difference was observed. Adverse events were frequent during prolonged administration of linezolid (34.3%), requiring treatment discontinuation in 12.8%. The most common event was anaemia (13.4%) followed by gastrointestinal symptoms (11.1%). In conclusion, linezolid seems a good oral treatment alternative for orthopaedic implant infections due to Gram-positive cocci resistant to β-lactams and fluoroquinolones. However, close monitoring of adverse events is required.

Prophylaxis with Teicoplanin and Cefuroxime Reduces the Rate of Prosthetic Joint Infection after Primary Arthroplasty

ABSTRACT The aim of this study was to compare the prosthetic joint infection (PJI) rate after total joint arthroplasty in two consecutive periods of treatment with different antibiotic prophylaxes: cefuroxime versus cefuroxime plus teicoplanin. We retrospectively reviewed 1,896 patients who underwent total hip arthroplasty or total knee arthroplasty between March 2010 and February 2013. From March 2010 to August 2011, patients received 1.5 g of cefuroxime during induction of anesthesia and another 1.5 g 2 h later (the C group). From September 2011, 800 mg of teicoplanin was added to cefuroxime (the CT group). Throughout the period studied, there were no variations in pre- or postoperative protocols. Univariate and multivariate analyses were performed to evaluate independent predictors of PJI. There were 995 (55.7%) patients in the C group and 791 (44.3%) in the CT group. Patients in the CT group had a significantly lower PJI rate than patients in the C group (1.26% versus 3.51%, P = 0.002). There were no infections due to Staphylococcus aureus in the CT group (0% versus 1.6% in the C group, P < 0.001). A stepwise forward Cox regression model identified male sex (hazard ratio [HR], 3.85; 95% confidence interval [CI], 2.09 to 7.18), a body mass index of ≥35 kg/m2 (HR, 2.93; 95% CI, 1.37 to 6.27), the presence of lung disease (HR, 2.46; 95% CI, 1.17 to 5.15), and red blood cell transfusion (HR, 3.70; 95% CI, 1.89 to 7.23) to be independent variables associated with a higher risk of PJI. The addition of teicoplanin was associated with a lower risk of infection (HR, 0.35; 95% CI, 0.17 to 0.74). In conclusion, the addition of teicoplanin to cefuroxime during primary arthroplasty was associated with a significant reduction in the global PJI rate due to a reduction of infections caused by Gram-positive bacteria.

Risk factors for failure in early prosthetic joint infection treated with debridement. Influence of etiology and antibiotic treatment

Purposes The aim of the present study was to evaluate the importance of isolated microorganisms according to the Gram stain and the type of antibiotic received on the outcome of early prosthetic joint infection (PJI) treated with debridement, antibiotics and implant retention (DAIR). Methods From January 1999 to December 2009, all patients with an early PJI were prospectively registered in a database and they were retrospectively reviewed for this study. Results During the study period, 160 patients met the inclusion criteria of the study. After a mean (SD) post-debridement follow-up of 5.2 (2.5) years, 117 patients (73.1%) were considered to be in remission and 43 (26.9%) were classified as failure. Variables associated with failure were liver cirrhosis (66.7% vs. 22.8%, p=0.001), diagnosis within the first 30 days from arthroplasty (30.4% vs. 8.0%, p=0.020), C-reactive protein (CRP) >12 mg/dl (46.7% vs. 21.2%, p=0.005), microorganism isolated in all deep samples (31.1% vs. 16.0%, p=0.047) and Gram-negative (GN) infection not treated with a fluoroquinolone (57.1% vs. 20.0%, P=0.004). Gram-positive (GP) infection not treated with rifampin was close to be statistically significantly associated with failure (34.4% vs. 19.2%, p=0.067). A multivariate analysis identified liver cirrhosis (OR: 12.4 CI95%: 3.1-49.7, p<0.001), CRP-value (OR: 1.06 CI95%: 1.0-1.11, p=0.049), and when a GN-infection was not treated with a fluoroquinolone (OR: 6.5, CI95%: 1.8-23.8, p=0.005) as independent predictors of failure. Conclusion The remission rate of PJI treated with DAIR after 3 years of follow-up was 73%. The main predictors of failure were liver cirrhosis, the selected antibiotic most specially fluoroquinolones for GN and rifampin for GP infections, the C-reactive protein and the number of samples culture positive as a potential surrogate markers of bacterial density.

Special Issues Involving Periprosthetic Infection in Immunodeficiency Patients

Chronic systemic illnesses such as diabetes mellitus, chronic kidney disease (CKD), liver cirrhosis, neoplasia, etc. have been clearly associated with high rates of SWI. However, the exact mechanisms underlying these observations are still under investigation. Chronic kidney disease (CKD) is a growing problem in our society. Many of these patients will require an arthroplasty and it appears that the prosthetic infection risk for these types of patients is much higher than in the normal population. The risk of complications due to infection seems to be lower in patients with kidney transplants than in patients undergoing haemodialysis. Both prophylaxis and treatment of infection in patients with CKD should be carried out with a strict monitoring of potentially nephrotoxic antibiotics. The literature on the prognosis and risk of infection in patients with haematopoietic stem cell transplant is scarce and occasionally contradictory. The optimal time for the surgery should be determined by taking into account the immunological state of the patient and should be avoided, as much as possible, during the first year after the HSCT. Child’s classification system is the most widely used method of stratifying the surgical risk for patients with cirrhosis; the infection appeared to be associated in a statistically significant way with advanced age and a Child B pre-operative classification. The prevention of prosthetic joint infections in HIV-infected patients should not be significantly different from the prevention for any other patient. Those patients that receive adequate antiretroviral treatment and periodic laboratory control show infection rates and periprosthetic complications that are similar to those for patients not affected by HIV. Therefore, the patient’s level of immunodeficiency is the most important prognostic factor for prosthetic infection. The particular immunological condition of these patients can lead to infections due to particular microorganisms that immunocompetent patients do not have to deal with. Of all possibilities, because of their frequency and difficulty to treat, infections caused by methicillin-resistant S. aureus and fungus are highlighted.

Correlation Between Visual Inspection and Ultrasonography to Identify the Distal Branches of the Superficial Peroneal Nerve: A Cadaveric Study

The anatomy of the superficial peroneal nerve (SPN) and, more precisely, of the distal branches of the SPN at the ankle has attracted interest owing to the possibility of injury when performing ankle arthroscopy. The anterolateral portal is one of the most commonly used portals in ankle arthroscopy, and the intermediate dorsal cutaneous nerve can easily be injured during portal placement. The purpose of the present study was to assess whether visual inspection and palpation of the cutaneous nerves at the ankle differed from examination with ultrasonography and whether the 2 examination techniques correlated with the anatomic location of the SPN, which was verified by cadaver dissection. First, visual examination and palpation was performed to identify the SPN, after which 12 cadaver legs from separate specimens were examined with ultrasonography to mark the course of the SPN. We then measured the distance between the nerve as identified with gross visualization/palpation and ultrasound examination, and compared these with the precise location determined by anatomic dissection. The use of ultrasonography to determine the course of the SPN was good or excellent in 11 of the 12 legs (91.7%) studied. In contrast, gross visualization/palpation was good or excellent in 4 legs (33.3%). Excellent agreement was observed between the ultrasound markings and the anatomic dissection results. However, the visual examination poorly identified the course and the anatomic variations of the nerve branches evidenced in the anatomic dissection. From these findings in cadaver specimens, ultrasound identification of the SPN and its branches is likely preferable to gross visualization/palpation before placement of the anterolateral arthroscopic portal to the ankle.