Different femoral rotation with navigated flexion-gap balanced or measured resection in total knee arthroplasty does not lead to different clinical outcomes.

PURPOSE: Femoral rotation in total knee arthroplasty (TKA) is hypothesized to vary in the same knee depending on the method used to establish it. METHODS: Thirty-eight patients who underwent TKA surgery using a measured resection technique (RT) were compared with 40 patients who underwent a flexion-gap balancing technique with computer-assisted (for navigation) surgery (FB-CAS) to assess clinical and radiographic alignment differences at two years postoperatively. In 36 of the 40 patients in the FB-CAS group, both methods were used. Intraoperatively, the transepicondylar femoral rotation (TEFR) in reference to the transepicondylar axis was established as the rotation that balanced the flexion gap. Once the TEFR was obtained, an analogous rotation as measured by a posterior reference femoral rotation (PRFR) cutting guide was determined. RESULTS: Femoral component rotation determined by the TEFR and PRFR methods differed in each of the knees. The median TEFR was 0.08°±0.6° (range - 1.5°, 1.5°), and the median PRFR was 0.06°±2.8° (range - 6°, 5°). The mean difference in the rotational alignment between the TEFR and PRFR techniques was 0.01° ± 3.1°. The 95% limits of agreement between the mean differences in measurements were between 6.2° external rotation and - 6.1° internal rotation. At 2 years postoperatively, we found no differences in the radiographic or clinical American Knee Society score between the two groups. CONCLUSION: Rotation of the femoral component in TKA can vary in the same knee depending on the surgical method used to establish it. This variation in femoral rotation is sufficiently small enough to have no apparent effect on the 2-year clinical outcome score. LEVEL OF EVIDENCE: II.

Prevalence and Impact of Positive Intraoperative Cultures in Partial Hip or Knee Revision.

BACKGROUND: Our aim is to investigate the impact of unexpected positive cultures on the outcome of partial prosthetic revisions. METHODS: Data regarding patients who underwent a partial hip or knee revision from 2003 and 2012 with the preoperative diagnosis of aseptic loosening was retrospectively reviewed. The protocol of revision included at least 3 intraoperative cultures. Failure was defined as the need for re-revision due to aseptic or septic loosening at 5 years. RESULTS: A total of 99 hip and 46 knee partial revisions were included. All cases had at least 5 years of follow-up. Ninety-seven cases (66.9%) had all cultures negative, 35 (24.1%) a single positive culture and 13 (9.0%) ≥2 positive cultures for the same microorganism. The median time from primary arthroplasty to partial revision was significantly shorter for patients with ≥2 positive cultures (26 months) than in those with all cultures negative (48 months) or with a single positive culture (51 months). Partial revisions performed within the first 5 years of implantation had a higher 5-year re-revision rate. The presence of a single positive culture during the partial exchange was not associated with a higher re-revision rate (2 of 35, 5.7%) than in those with negative cultures (3 of 97, 3.1%). On the contrary, re-revision rate was significantly higher in cases with ≥2 positive cultures (3 of 13, 23.1%) than in those with negative cultures (P = .02). CONCLUSION: Partial revisions performed within the first 5 years from implantation and ≥2 intraoperative positive cultures were associated with a higher re-revision risk at 5 years.

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.

Prophylaxis with teicoplanin and cefuroxime reduces the rate of prosthetic joint infection after primary arthroplasty.

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.

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 ß-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 ß-lactams and fluoroquinolones. However, close monitoring of adverse events is required.

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.

Antimicrobials in polymethylmethacrylate: from prevention to prosthetic joint infection treatment: basic principles and risk of resistance.

BACKGROUND: Excellent revisions about antibiotic-loaded bone cement (ALBC) have been recently published. In the present article, we review the principles and limitations of local antibiotic delivery in the context of recent advances in the pathogenesis of prosthetic joint infections (PJI), with particular attention paid to the potential association between ALBC and antimicrobial resistance. MAIN BODY: Recalcitrance of PJI is related to the ability of pathogens to adapt to particular environments present in bone tissue and protect themselves from host immunity in different ways. Accordingly, delivery of high local antimicrobial concentrations using ALBC is needed. Most relevant clinical data showing the efficacy of ALBC for PJI prophylaxis and treatment are reviewed, and we dissected the limitations on the basis of the recent findings from animal models and suggested that aminoglycosides, in particular, could not be the best option. One of the major concerns associated with ALBC is the emergence of resistance because of theoretical prolonged exposure to low antibiotic concentrations. We summarize the mechanisms for the selection of resistant microorganisms, and we critically reviewed the evidence from animal models and clinical data from observational and registry studies and concluded that there is no evidence to support this association. CONCLUSION: While waiting for better evidence from well-designed clinical trials, ALBC shows a beneficial effect as a prophylaxis in arthroplasty, and to avoid the colonization of spacers used for two-stage revision in patients with PJI. Experimental models and clinical evidence suggest the need to achieve high local antimicrobial concentrations to obtain the highest prophylactic and therapeutic effect. The current evidence does not support the risk of increasing resistance with use of ALBC. In the future, it is necessary to evaluate new carriers and different antimicrobials to improve clinical outcomes.

Usefulness of serum D-dimer and platelet count to mean platelet volume ratio to rule out chronic periprosthetic joint infection.

Background: Diagnosing periprosthetic joint infection (PJI) is challenging and usually requires the evaluation of several biomarkers. Our main aim was to evaluate the usefulness of D-dimer levels as well as the platelet count (PC) to mean platelet volume (MPV) ratio serum as biomarkers to rule out chronic knee and hip infection. Methods: The study enrolled a prospective cohort of 93 patients undergoing hip or knee revision. D-dimer values, PC to MPV ratio, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were preoperatively determined and evaluated as a predictor of PJI. The definitive diagnosis of PJI was established according to the 2018 International Consensus Meeting criteria. Results: A total of 24 (25.8 %) cases were postoperatively diagnosed with PJI. The median D-dimer value was significantly higher ( p   <  0.001) for patients with PJI (1950 ng mL - 1 ) than for patients with aseptic failure (700 ng mL - 1 ). The area under the receiver operating characteristic curves for D-dimer, CRP and ESR was 0.820, 0.793 and 0.791 respectively. D-dimer  ≥  950 ng mL - 1 (91 % sensitivity, 64 % specificity), CRP  ≥  1.95 mg dL - 1 (61 % sensitivity, 90 % specificity) and ESR  >  20 (74 % sensitivity, 82 % specificity) were identified as the values with the best balance between sensitivity and specificity. The mean PC to MPV ratio was 37.0 for PJI patients and 29.8 for patients in the aseptic revision cohort ( p = 0 .067). Conclusions: Serum D-dimer levels appear very unlikely to remain normal in the presence of chronic PJI. The 91 % sensitivity when considering 950 ng mL - 1 as the threshold highlights D-dimer as the most accurate initial test to rule out chronic PJI. Conversely, the PC to MPV ratio may be of limited value for accurately diagnosing PJI.

Relationship between the degree of osteolysis and cultures obtained by sonication of the prostheses in patients with aseptic loosening of a hip or knee arthroplasty.

INTRODUCTION: The pathogenesis of prosthesis loosening is not well understood. The aim of our study was to sonicate components of joint prostheses removed due to aseptic loosening, culture the sonicate fluid, and to correlate these results with the degree of radiological osteolysis. METHODS: From January 2008 to June 2009 all consecutive patients who underwent a revision of hip or knee prosthesis due to aseptic loosening were included in the study. Aseptic loosening was established when the patient had radiological signs of loosening without symptoms or signs of infection. The diagnosis was confirmed when histology was negative, and ≥ 5 out of 6 standard cultures of periprosthetic tissue were negative. Bone lysis was measured according to the Paprosky or Engh classifications without knowing the result of sonication cultures. Removed components were placed in sterile bags and immediately transported to the microbiology laboratory and sonicated. Sonicate fluid was cultured and the results were correlated with the degree of bone lysis. The proportion of components with positive sonication culture according to the bone lysis classification was compared using χ(2) test. RESULTS: A total of 52 patients were included and 123 components were sonicated. In 30 patients at least 1 sonicated component was positive (57.7%) and 44 out of 123 (35.8%) components were positive. The proportion of positive sonication cultures was significantly higher in the group of components with a higher degree of bone lysis of 3 (76.5%) than in those with lower degrees (33.9% for 1 and 24% for 2) (χ(2) test, p = 0.0004). CONCLUSIONS: Sonication cultures were positive in 57% of patients who underwent revision arthroplasty for aseptic loosening. The percentage of positive sonication cultures was significantly higher in patients with severe osteolysis. LEVEL OF EVIDENCE: level I of Prognostic Studies-Investigating the Effect of a Patient Characteristic on the Outcome of Disease.

Blood culture flasks for culturing synovial fluid in prosthetic joint infections.

BACKGROUND: Identifying the etiologic microorganism is essential to guide antimicrobial therapy in prosthetic joint infection. QUESTIONS/PURPOSE: We (1) compared the frequency of positive cultures with synovial fluid inoculated in blood culture flasks (SF) with those of periprosthetic tissues or swabs in traditional cultures from patients with acute and chronic prosthetic joint infections (PJI) and (2) determined the sensitivity, specificity, and predictive values of the three methods. PATIENTS AND METHODS: We retrospectively reviewed 87 patients with PJIs (54 knees, 33 hips) and 63 patients with aseptic loosening (34 knees, 29 hips). Two SF, periprosthetic tissue, and swab samples were taken for culture in all 150 patients except for 14 in whom only one SF fluid sample was obtained. Synovial fluid was inoculated in blood culture flasks and periprosthetic tissue and swab samples in standard media. Positive cultures were identified with standard biochemical procedures. RESULTS: SF samples were positive in 78 of 87 infected cases (90%), periprosthetic tissue samples were positive in 71 (82%), and swab samples were positive in 59 (68%). SF, periprosthetic tissue, and swab samples were positive more frequently in acute than in chronic infections (96% versus 82% for SF, 87% versus 74% for periprosthetic tissue, and 87% versus 44% for swabs). The sensitivity, specificity, and positive and negative predictive values of SF were 91, 100, 100, and 93 for acute infections and 79, 100, 100, and 88 for chronic infections, respectively. CONCLUSIONS: SF samples cultured in flasks had higher sensitivity, specificity, and positive and negative predictive values for diagnosis of PJI when compared with standard tissue and swab samples. The usefulness of all samples was less in chronic than in acute infections. LEVEL OF EVIDENCE: Level II, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Outcome of acute prosthetic joint infections due to gram-negative bacilli treated with open debridement and retention of the prosthesis.

The aim of our study was to evaluate the outcome of acute prosthetic joint infections (PJIs) due to gram-negative bacilli (GNB) treated without implant removal. Patients with an acute PJI due to GNB diagnosed from 2000 to 2007 were prospectively registered. Demographics, comorbidity, type of implant, microbiology data, surgical treatment, antimicrobial therapy, and outcome were recorded. Classification and regression tree analysis, the Kaplan-Meier survival method, and the Cox regression model were applied. Forty-seven patients were included. The mean age was 70.7 years, and there were 15 hip prostheses and 32 knee prostheses. The median number of days from the time of arthroplasty was 20. The most frequent pathogens were members of the Enterobacteriaceae family in 41 cases and Pseudomonas spp. in 20 cases. Among the Enterobacteriaceae, 14 were resistant to ciprofloxacin, while all Pseudomonas aeruginosa isolates were susceptible to ciprofloxacin. The median durations of intravenous and oral antibiotic treatment were 14 and 64 days, respectively. A total of 35 (74.5%) patients were in remission after a median follow-up of 463 days (interquartile range, 344 to 704) days. By use of the Kaplan-Meier survival curve, a C-reactive protein (CRP) concentration of < or = 15 mg/dl (P = 0.03) and receipt of a fluoroquinolone, when all GNB isolated were susceptible (P = 0.0009), were associated with a better outcome. By use of a Cox regression model, a CRP concentration of < or = 15 mg/dl (odds ratio [OR], 3.57; 95% confidence interval [CI], 1.05 to 12.5; P = 0.043) and receipt of a fluoroquinolone (OR, 9.09; 95% CI, 1.96 to 50; P = 0.005) were independently associated with better outcomes. Open debridement without removal of the implant had a success rate of 74.5%, and the factors associated with good prognosis were a CRP concentration at the time of diagnosis < or = 15 mg/dl and treatment with a fluoroquinolone.

Timing of antibiotic prophylaxis for primary total knee arthroplasty performed during ischemia.

BACKGROUND: There is no clinical trial analyzing the best moment to infuse an antibiotic during knee arthroplasty performed during ischemia. We designed a single-center, randomized, double-blind, placebo-controlled trial to evaluate whether antibiotic therapy should be administered before tourniquet inflation or just before tourniquet deflation. MATERIAL AND METHODS: Patients who underwent a primary knee arthroplasty were randomized to receive (1) 1.5 g of cefuroxime 10-30 min before inflation of the tourniquet and placebo 10 min before release of the tourniquet (standard arm) or (2) placebo 10-30 min before inflation of the tourniquet and 1.5 g of cefuroxime 10 min before release of the tourniquet (experimental arm). In both arms, a postoperative dose of 1.5 g of cefuroxime was given 6 h after the surgical procedure. The main variables associated with the rate of deep-tissue infection after 3 and 12 months of follow-up were gathered. Continuous variables were compared using Student's t test, and categorical variables were compared using the chi(2) test or Fisher's exact test. RESULTS: From September 2004 through December 2005, a total of 908 patients were randomized, 442 and 466 of whom were allocated to the standard and experimental arms, respectively. There were no differences between treatment arms in terms of age, sex, comorbidity, American Society of Anaesthesiologists score, duration of surgery, need of blood transfusion, or fourth-day hematocrit. The rates of deep-tissue infection among the standard and experimental groups were 3.4% and 1.9%, respectively, at 3 months of follow-up (P = .21) and 3.6% and 2.6%, respectively, at 12 months of follow-up (P = .44). CONCLUSION: The administration of prophylactic antibiotics just before tourniquet release was not inferior to standard antibiotic prophylaxis.

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.

Prosthetic joint infections due to methicillin-resistant and methicillin-susceptible staphylococci treated with open debridement and retention of the prosthesis.

OBJECTIVES: To compare the specific characteristics, the outcome and the predictors of failure of prosthetic joint infections (PJI) due to methicillin-resistant (MRS) and methicillin- susceptible staphylococci (MSS) treated with open debridement and retention of the implant. MATERIAL AND METHODS: PJI due to MRS or MRS prospectively registered in a database from 1999 to 2009 were retrospectively reviewed. RESULTS: During the study period, 96 patients met the inclusion criteria of the study. The mean follow-up period was 3.9 years and at least 2 years in all patients. The failure rate was 25%. The only variable significantly associated with failure in the global cohort was polymicrobial infection (59.3% vs. 40.7%, p=0.036). Thirty-four (35.4%) patients had an infection due to MRS and 62 (63.6%) due to MSS. Among MSS infections, 95.2% corresponded to primary arthroplasties while 29.4% of PJI due to MRS were after revision arthroplasties (p=0.001). CRP was significantly higher in PJI due to MSS (5.2 mg/dl vs 9.1 mg/dL, p=0.02).The failure rate (20% vs 27%, p=0.62) was very similar in MSS and MRS groups. CONCLUSION: PJI due to MRS were mainly coagulase-negative staphylococci, more frequent after revision arthroplasties, had a lower inflammatory response, and had a similar failure rate than MSS infections.

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 pro-gnosis. 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.

Prosthetic joint infections due to methicillin-resistant and methicillin-susceptible staphylococci treated with open debridement and retention of the prosthesis

Objetivo. Comparar las características específicas, los resultados y los factores predictivos de mal pronóstico de las infecciones de prótesis articulares (IPA) por estafilococos me¬ticilin-resistentes (EMR) y meticilin-sensibles (EMS) tratadas mediante desbridamiento, retención del implante y tratamien¬to antibiótico. Material y métodos. Se realizó una revisión retrospectiva de todas las IPA’s por EMR o EMS registradas en nuestra base datos desde 1999 a 2009. Resultados. Durante el periodo del estudio, 96 pacien¬tes cumplieron los criterios de inclusión en el estudio. El se¬guimiento medio de los pacientes fue de 3,9 años y todos los pacientes tenían al menos 2 años de seguimiento. La tasa de fracaso fue del 25%. La única variable asociada significativa¬mente a fracaso terapéutico en el total de pacientes fue la infección polimicrobiana (59,3% vs. 40,7%, p=0,036). Treinta y cuatro (35,4%) pacientes tuvieron una infección por EMR y 62 (63,6%) por EMS. Respecto las infecciones por EMS, el 95,2% correspondían a cirugías primarias mientras que el 29,4% de las IPA’s por EMR ocurrieron tras cirugías de revision (p=0,001). El valor de la PCR fue significativamente superior en las IPA’s por EMS (5,2 mg/dl vs 9,1 mg/dL, p=0,02). La tasa de fracaso fue similar en las infecciones por EMS y EMR (20% vs 27%, p=0,62). Conclusión. Las IPA’s por EMR fueron causadas principal¬mente por estafilococos coagulase-negativo, ocurrieron más frecuentemente tras cirugías de revisión, tenían una reacción inflamatoria menor y obtuvieron una tasa de fracaso similar a las infecciones por EMS (AU)

Objectives. To compare the specific characteristics, the outcome and the predictors of failure of prosthetic joint in¬fections (PJI) due to methicillin-resistant (MRS) and methicil¬lin-susceptible staphylococci (MSS) treated with open debride¬ment and retention of the implant. Material and methods. PJI due to MRS or MRS prospec¬tively registered in a database from 1999 to 2009 were retro¬spectively reviewed. Results. During the study period, 96 patients met the in¬clusion criteria of the study. The mean follow-up period was 3.9 years and at least 2 years in all patients. The failure rate was 25%. The only variable significantly associated with fail¬ure in the global cohort was polymicrobial infection (59.3% vs. 40.7%, p=0.036). Thirty-four (35.4%) patients had an in¬fection due to MRS and 62 (63.6%) due to MSS. Among MSS infections, 95.2% corresponded to primary arthroplasties while 29.4% of PJI due to MRS were after revision arthroplas¬ties (p=0.001). CRP was significantly higher in PJI due to MSS (5.2 mg/dl vs 9.1 mg/dL, p=0.02).The failure rate (20% vs 27%, p=0.62) was very similar in MSS and MRS groups. Conclusion. PJI due to MRS were mainly coagulase-nega¬tive staphylococci, more frequent after revision arthroplasties, had a lower inflammatory response, and had a similar failure rate than MSS infections (AU)

Long-term outcome of acute prosthetic joint infections due to gram-negative bacilli treated with retention of prosthesis

Objetivo: Actualizar la información clínica de 47 pacientes con una infección de una prótesis articular por bacilos gramnegativos incluidos en un estudio previo y determinar los factores asociados a fracaso tras un seguimiento prolongado. Métodos: Utilizando la historia médica electrónica de nuestro hospital, se revisó toda la información sobre reingresos, nuevos procedimientos quirúrgicos, el motivo de la reintervención quirúrgica (infección o aflojamiento aséptico) y la fecha de la última visita en el hospital. La historia de los 35 pacientes que fueron considerados curados en la publicación previa, fueron revisados. Resultados: En 30 pacientes no hubo evidencia clínica de fracaso y no requirieron intervenciones adicionales sobre la prótesis infectada después de un periodo largo de seguimiento. En 5 casos se identificó una complicación tardía. En un caso el paciente tuvo una reinfección por un estafilococo coagulasa-negativa después de 22 meses del primer desbridamiento y requirió un recambio en 2 tiempos. Los otros 4 casos desarrollaron un aflojamiento aséptico y fue necesario realizar un recambio en 1 tiempo. Recibir una fluoroquinolona cuando todos los microorganismos causales de la infección eran sensibles fue el único factor asociado con remisión de la infección en el análisis univariado (p=0.002). Conclusión: Después de un seguimiento prolongado, nuestros resultados apoyan la importancia de utilizar fluoroquinolonas en infecciones agudas de prótesis articulares por bacilos gramnegativos(AU)

Objective: To update the clinical information of the 47 patients with a prosthetic joint infection due to Gram-negative bacilli included in a previous study and to reassess the predictors of failure after a longer follow-up. Methods: Using the electronic files of our hospital, all the information regarding readmissions to the hospital, new surgical procedures and the reason for the new surgery (infection, aseptic loosening), and the last visit in the hospital were registered. The medical chart of the 35 patients that were considered in remission in the previous publication was reviewed. Results: In 30 patients no clinical evidence of failure was detected and no additional surgery on the previously infected prosthesis was necessary and they were considered in long-term remission. In 5 cases a late complication was identified. One case had a reinfection due to coagulase-negative staphylococci after 22 months from the open debridement and required a 2-stage revision surgery. The other 4 cases developed an aseptic loosening and it was necessary to perform a 1-stage exchange. Receiving a fluoroquinolone when all the Gram-negatives involved in the infection were susceptible to fluoroquinolones was the only factor associated with remission in the univariate analysis (p=0.002). Conclusion: After a long-term follow-up, our results support the importance of using fluoroquinolones in acute PJI due to Gram-negative bacilli(AU)

Usefulness of monitoring linezolid trough serum concentration in prolonged treatments

Linezolid ha demostrado ser eficaz en el tratamiento de infecciones musculo-esqueléticas, sin embargo, se han descrito casos de fracaso, desarrollo de resistencia y toxicidad en tratamientos de más de 28 días. Describimos nuestra experiencia en 5 casos consecutivos en los que la concentración de linezolid se determinó semanalmente y su relación con la respuesta clínica y la toxicidad(AU)

Linezolid has proven valuable in musculoskeletal infections, however, failure and resistance have been described and toxicity is worrisome when more than 28 days are necessary. We describe the first 5 cases in whom linezolid trough serum concentrations were weekly measured and its relationship with clinical outcome and toxicity(AU)