Early Prosthetic Joint Infection Research Articles

Management of the exposed total knee prosthesis, a six-year review

IntroductionAn exposed knee prosthesis is a limb threatening condition. Our unit manages such cases according to a multidisciplinary orthoplastic protocol. Whilst early prosthetic joint infection with dehiscence may be managed by Debridement, Antibiotics and Implant Retention (DAIR) and soft tissue coverage, the majority of these cases are chronic and in our unit are managed by Debridement, Explantation, Antibiotics (spacer and systemic) and Flap (DEAF). Patients and methodsWe report our experience of managing 17 of these challenging cases, 16 DEAFs and one DAIR and flap. Outcomes were assessed clinically and using the 36-item Short Form Health Survey (SF-36). ResultsThe mean time from arthroplasty to presentation in our unit was 19months (range: 0.5–80). Whilst an open knee replacement is by definition ‘infected’, significant microbiological growth from deep tissue/fluid samples was only detected in 14 patients (82%). Five patients (29.4%) subsequently underwent an amputation. Of these five, three patients were extensor deficient at presentation. At follow-up, health-related quality of life scoring using the Short Form-36 demonstrated poor physical function and highlighted differences in emotional function and pain levels between patients whose limbs were salvaged and patients who underwent amputation. ConclusionAn exposed total knee prosthesis is a devastating complication, which despite our multidisciplinary salvage approach, has a high rate (5/17=29%) of amputation in this series. Quality of life in this patient group is poor irrespective of limb salvage. Salvage surgery was associated with worse pain, but better emotional profile than patients with an above knee amputation.

The impact of patient and surgical factors on the rate of infection after primary total knee arthroplasty: an analysis of 64,566 joints from the New Zealand Joint Registry.

The aim of this study was to identify risk factors for prosthetic joint infection (PJI) following total knee arthroplasty (TKA). The New Zealand Joint Registry database was analysed, using revision surgery for PJI at six and 12 months after surgery as primary outcome measures. Statistical associations between revision for infection, with common and definable surgical and patient factors were tested. A total of 64 566 primary TKAs have been recorded on the registry between 1999 and 2012 with minimum follow-up of 12 months. Multivariate analysis showed statistically significant associations with revision for PJI between male gender (odds ratio (OR) 1.85, 95% confidence interval (CI) 1.24 to 2.74), previous surgery (osteotomy (OR 2.45 95% CI 1.2 to 5.03), ligament reconstruction (OR 1.85, 95% CI 0.68 to 5.00)), the use of laminar flow (OR 1.6, 95% CI 1.04 to 2.47) and the use of antibiotic-laden cement (OR 1.93, 95% CI 1.19 to 3.13). There was a trend towards significance (p = 0.052) with the use of surgical helmet systems at six months (OR 1.53, 95% CI 1.00 to 2.34). These findings show that patient factors remain the most important in terms of predicting early PJI following TKA. Furthermore, we found no evidence that modern surgical helmet systems reduce the risk of PJI and laminar flow systems may actually increase risk in TKA. The use of this registry data assists the estimation of the risk of PJI for individual patients, which is important for both informed consent and the interpretation of infection rates at different institutions. Infection rates in TKA are related to both individual patient and surgical factors, and some modern methods of reducing infection may actually increase infection risk.

Good quality of life outcomes after treatment of prosthetic joint infection with debridement and prosthesis retention

Patients treated for early prosthetic joint infection (PJI) with surgical debridement and prosthesis retention have a rate of successful infection eradication that is similar to patients treated with the traditional approach of prosthesis exchange. It is therefore important to consider other outcomes after prosthetic joint infection treatment that may influence management decisions, such as quality of life (QOL). Our aim was to describe infection cure rates and quality of life for patients with prosthetic joint infection treated with debridement and prosthesis retention and to determine if treatment with this approach was a risk factor for poor quality of life outcomes. Prospectively collected pre and post-arthroplasty data were available for 2,134 patients, of which PJI occurred in 41. For patients treated for prosthetic joint infection, the 2-year survival free of treatment failure was 87% (95%CI 84-89). Prosthetic joint infection cases treated with debridement and retention had a similar improvement from pre-arthroplasty to 12-months post-arthroplasty as patients without PJI in QOL according to the SF-12 survey. Prosthetic joint infection treated with debridement and retention was not a risk factor for poor quality of life on univariate or multivariate analysis. Prosthetic joint infection treated with debridement and prosthesis retention results in good cure rates and quality of life. Further studies are required that directly compare quality of life for different surgical approaches for prosthetic joint infection to better inform management decisions. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:898-902, 2016.

Predictors of treatment outcome in prosthetic joint infections treated with prosthesis retention.

The reported success rates of debridement, antibiotics, and implant retention (DAIR) for prosthetic joint infections (PJIs) vary widely. Several risk factors have been described for treatment failure, but they vary between studies. The purpose of this study was to evaluate the predictors of DAIR failure in PJI treatment and to assess the efficacy of rifampin combined with ciprofloxacin versus rifampin combined with other antibiotics in staphylococcal PJIs. Patients with PJI that underwent DAIR for the first time between February 2001 and August 2009 were identified retrospectively in the hospital's patient databases. A total of 113 PJI cases with early postoperative or acute haematogenous PJI were followed for up to two years from the start of treatment. In univariate analysis, variables significantly associated with treatment failure were acute haematogenous infections (p = 0.022), leucocyte count at admission > 10 × 10(9)/l (p < 0.01), pain in the joint (p < 0.01), and ineffective empirical antibiotics (p < 0.01). In a multivariate Cox model, leucocyte count > 10 × 10(9)/l and ineffective empirical antibiotics were significant risk factors for failure. Compared to rifampin-ciprofloxacin, the hazard ratio (HR) for treatment failure was significantly increased in the rifampin-other antibiotics group (HR 6.0, 95% CI 1.5-28.8, p = 0.014) and the group treated without rifampin (HR 14.4, 95% CI 3.1-66.9, p < 0.01). Rifampin-ciprofloxacin combination therapy was significantly more effective than rifampin combined with other antibiotics. Effective empirical antibiotics are essential for successful PJI treatment.

KLIC-score for predicting early failure in prosthetic joint infections treated with debridement, implant retention and antibiotics

Debridement, irrigation and antibiotic treatment form the current approach in early prosthetic joint infection (PJI). Our aim was to design a score to predict patients with a higher risk of failure. From 1999 to 2014 early PJIs were prospectively collected and retrospectively reviewed. The primary end-point was early failure defined as: 1) the need for 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%). Treatment of 52 (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% CI1.16–16.62) compared with primary arthroplasty, C reactive protein >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). A score for predicting the risk of failure was designed using preoperative factors (KLIC-score: Kidney, Liver, Index surgery, Cemented prosthesis and C-reactive protein value) and it ranged between 0 and 9.5 points. Patients with scores of ≤2, >2–3.5, 4–5, >5–6.5 and ≥7 had failure rates 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.

Efficacy of Debridement for Early Periprosthetic Joint Infection after Hip Arthroplasty

PurposeIn early prosthetic joint infection after hip arthroplasty, debridement with prosthesis retention may be performed for implant salvage, but the reported success rates are highly variable. Hence we reviewed the outcome of radical debridement and retention of prosthesis using established diagnostic criteria and surgical procedures in relation to significant variables including clinical characteristics, pathogenicity, and antibiotic treatment.Materials and MethodsWe retrospectively reviewed 20 patients (11 men and 9 women) with early prosthetic joint infection after unilateral hip arthroplasty, treated by radical debridement with retention of prosthesis from January 2000 to May 2011. Average follow-up period was 55 months (12-178 months). The outcome was evaluated and analyzed based on recurrence of infection and clinical (Harris hip score) and radiological criteria.ResultsPathogens were isolated from 11 hips (methicillin-resistant Staphylococcus aureus [MRSA] in three, methicillin-resistant Staphylococcus epidermidis [MRSE] in two, methicillin-sensitive Staphylococcus aureus [MSSA] in one, Acinetobacter baumannii in two, Enterococcus faecalis in two patients, and Enterococcus, Citrobacter species in one). The mean duration of antibiotic administration was 43.5 days. Recurrence of infection was not observed in any case. Average Harris hip score was 91 points at the last follow-up. Revision surgery was not required for any reason including implant failure. Dislocation occurred in two hips after debridement and was treated conservatively.ConclusionRadical debridement with prosthesis retention is an effective procedure for early prosthetic joint infection after hip arthroplasty in carefully selected patients and with early diagnosis.

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

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). 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. 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. 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.

Current concepts in the management of prosthetic joint infection.

Prosthetic joint infection (PJI) is a serious complication of arthroplasty that is associated with significant mortality, morbidity and costs. PJI is difficult to cure because causative bacteria form and persist in biofilm adherent to the prosthesis surface. PJI can be classified into early, delayed or late according to the time of onset after insertion of the prosthesis, and this classification can help determine pathogenesis and appropriate management. Traditional treatment has been with prolonged intravenous antibiotics and prosthesis exchange, which has been successful in treating infection but is technically difficult and has high rates of associated morbidity. On the basis of in vitro and animal studies, interest has turned to the use of antimicrobials that are particularly active against biofilm-associated bacteria. Recent clinical evidence shows success in more than 77% of early PJI with surgical debridement, retention of prosthesis and the use of rifampicin-based combinations for staphylococcal PJI. Fluoroquinolones are preferred for Gram-negative PJI. Optimal antimicrobial treatment duration and the management of polymicrobial, enterococcal, fungal and culture-negative infections are still yet to be defined but will become more clear as the results of current research comes to hand.

Early infection of hip joint prosthesis by Clostridium difficile in an HIV-1 infected patient

Anaerobes are less frequently described as causative pathogen of prosthetic joint infection (PJI). We report the first case of early PJI after hip arthroplasty due to Clostridium difficile in a diabetic and HIV-1 infected patient with bacteremia. Our patient was successfully treated through surgical debridement and prosthesis retention combined with targeted antibiotic therapy.

Characteristics and treatment outcomes of 69 cases with early prosthetic joint infections of the hip and knee

Early prosthetic joint infection (PJI) can be treated with an intensive surgical debridement and implant retention (DAIR) of the prosthesis if (1) the prosthesis is stable, (2) the pathogen is not a difficult-to-treat microorganism, (3) symptoms have lasted for <3 weeks and (4) a sinus tract is absent. We retrospectively evaluated the treatment outcome of early PJI in the hip and knee in a single orthopaedic centre. An early PJI was defined as a prosthesis infection within 3 months after primary implantation or revision surgery for a non-infectious cause. We identified 69 patients with confirmed early PJI, with a median age of 71 (range 33-84) years. Only 64 % presented with ≥2 acute signs of infection. The most commonly isolated bacteria were coagulase-negative staphylococci (38 %) and Staphylococcus aureus (25 %). Surgical procedures included DAIR (50 cases, 69 %) and two-stage exchange (19 cases, 31 %). At last follow-up, five of remaining living 67 patients (7.5 %) had a relapse of infection. The overall relapse-free survival of the prosthesis after 2 years was 92.3 % (95 % confidence interval 82-97 %) with no significant difference between DAIR and exchange of prosthesis. Our data suggest that an early PJI should be treated with DAIR as a less invasive procedure whenever possible according to the established treatment algorithm.

Oral Antibiotic Therapy

Oral Antibiotic Therapy

Irrigation and Debridement

Irrigation and Debridement

Preoperative Asymptomatic Leucocyturia and Early Prosthetic Joint Infections in Patients Undergoing Joint Arthroplasty

Prosthetic joint infection (PJI) is associated with a higher mortality, morbidity and economic costs. Although it is well known that the presence of urinary tract infection (UTI) is associated with PJI, few investigations evaluated the preoperative asymptomatic leukocyturia (ASL) and the possible relationship with early PJI. We reviewed the records of 739 patients performed primary joint arthroplasty. A total of 131 patients had preoperative ASL (17.7%) and 7 of 739 patients (0.9%) had early PJI. Preoperative ASL was not confirmed as a risk factor for early PJI on the multivariate regression analysis with an adjusted OR of 1.04 (P>0.05). Therefore, it should not be considered as a reason for postponement of total joint arthroplasty.

Early prosthetic hip joint infection treated with debridement, prosthesis retention and biofilm‐active antibiotics: functional outcomes, quality of life and complications

Patients treated for early prosthetic joint infection (PJI) with surgical debridement, prosthesis retention and biofilm-active antibiotics, such as rifampicin or fluoroquinolones have a rate of successful infection eradication that is similar to patients treated with the traditional approach of prosthesis exchange. It is therefore important to consider other outcomes after PJI treatment that may influence management decisions, such as function, quality of life (QOL) and treatment-associated complications. To describe rates of successful treatment for patients with PJI undergoing surgical debridement, prosthesis retention and biofilm-active antibiotics and compare their functional outcomes, QOL and complication rates to patients without PJI. Nineteen patients treated for PJI after hip arthroplasty with debridement, prosthesis retention and biofilm-active antibiotics were matched to 76 controls who underwent hip arthroplasty with no infection. Cumulative survival free from treatment failure at 2 years was 88% (95% confidence interval, 59-97%). PJI cases had significant improvement from pre-arthroplasty to 12-months post-arthroplasty in function according to Harris Hip Score and QOL according to the 12-item Short Form Health Survey Physical Component Summary. There was no significant difference in the improvement between controls and cases. PJI was not a risk factor for poor function or QOL. Medical complications occurred more frequently in cases (6/19 (32%)) than controls (9/76 (12%); P = 0.04), with this difference being accounted for by drug reactions. Surgical complications were the same in the two groups. Treatment of PJI with debridement, prosthesis retention and biofilm-active antibiotics is successful, well tolerated and results in significant improvements in function and QOL, which are similar to patients without PJI.

C-reactive protein (CRP) in different types of minimally invasive knee arthroplasty

C-reactive protein (CRP) is an acute-phase biomarker responding to surgical trauma. Typically, a first peak is observed at day 2 with a reduction at day 4 and normalization 3-6 weeks after surgery. CRP is often linked to prosthetic joint infection when elevated values are present longer time after surgery. The aim of this study was to analyse the kinetics of CRP in different types of minimally invasive (MI) arthroplasty and to observe if there were significant differences in between MI total knee arthroplasty (TKA), patient-specific instruments (PSI) TKA and unicompartmental arthroplasty (UKA). Three hundred and seventy-two patients were prospectively studied with a blood test measuring CRP at day 2, 4, 21 and 42 in 3 different groups of patients: 257 MI TKA, 55 PSI TKA and 60 UKA. Mean peak values and kinetics were compared in between different groups of MI arthroplasty. There was a significant age difference in the three MI arthroplasty groups. The difference in mean age for the conventional MI TKA group of 68.8 ± 9.8 years, 58.5 ± 11.7 years for the unicompartmental group (P < 0.05) and 63.3 ± 9.6 years for the PSI group (P < 0.05) was significant. Mean CRP level, for the entire study group, on day 2 was 16.7 ± 8.8 mg/dl that gradually decreased to 13.6 ± 7.8 mg/dl on day 4. On day 21 and 42, median CRP level was 0.6 (0-20) and 0.4 (0-7) mg/dl, respectively. Peak CRP values were lower for UKA compared to TKA at day 2 (11.6 vs. 17.5 mg/dl) and day 4 (8.0 vs. 15 mg/dl), but this was not observed for PSI-assisted arthroplasty (18.9 vs. 17.5 mg/dl). There was a trend for faster CRP normalization in UKA compared to the two other groups at day 21 and at day 42 and for PSI TKA to have a lower mean level at 4 days (12.9 vs. 15 mg/dl). There was no statistical difference in the normalization rate of PSI-assisted versus MI TKA. Kinetics of CRP in MI arthroplasty are identical to the published kinetics of conventional TKA. Most patients normalize CRP at 3 weeks; however, 18 % does not by 6 weeks. This is not a sign of early prosthetic joint infection. Peak values are significantly lower for UKA but not for PSI TKA.

Early onset prosthetic hip and knee joint infection: treatment and outcomes in Victoria, Australia

Prosthetic joint infection (PJI) remains a devastating complication of arthroplasty. There are no internationally endorsed consensus management guidelines and treatment approaches differ widely. The aim of this multicentre study was to examine treatment approaches and predictors of treatment failure in patients with early PJI managed in hospitals in Victoria, Australia. This cohort study was conducted across 10 hospitals over a three-year period (January 2006 to December 2008) and involved 147 patients who presented with early PJI. Most patients (76%) were managed with debridement and retention of the prosthesis. Patients were followed for a median 20 months (interquartile range: 7-36). Overall 43 patients experienced treatment failure with a 12-month infection-free survival estimate of 76% [95% confidence interval (CI): 68-83%]. The following factors were associated with treatment failure: septic revision arthroplasty (hazard ratio: 7.5; 95% CI: 2.4-23.1; P < 0.0001), hypotension at presentation (4.9; 1.5-15.7; P = 0.007), one-stage exchange (3.1; 1.0-9.2; P = 0.048), total duration of antibiotic therapy <90 days: specifically <30 days (18.5; 5.4-63.1; P < 0.001), 30-60 days (8.0; 2.6-23.9; P < 0.001) and 60-90 days (7.3; 2.2-24.4; P = 0.001), respectively. Effective empiric antibiotic therapy was associated with a decreased risk of treatment failure (0.20; 0.09-0.47; P < 0.001). The management approach in Australia differs from that used elsewhere in the world. We have identified a number of clinically relevant risk factors for treatment failure that may impact on treatment recommendations.

Early prosthetic joint infections treated with debridement and implant retention

Background and purpose Debridement and retention of the prosthesis is often attempted to treat early prosthetic joint infection (PJI). However, previous studies have found inconsistent results, with success rates ranging from 21% to 100%, and little has been written in the literature about hip function. We have therefore analyzed the clinical and functional outcome of early PJIs treated with this procedure.Patients and methods 38 patients with early PJI after primary hip arthroplasty who were treated with debridement and retention of the implant between 1998 and 2005 were studied prospectively, with a median follow-up time of 4 (0.8–10) years. Early infection was defined as that which occurred within 4 weeks of index arthroplasty. The primary outcome measure was infection control. Functional outcome was assessed with the Harris hip score.Results 27 of 38 patients were successfully treated, with no signs of infection or continued antibiotic treatment at the latest follow-up. Median Harris hip score was 86 (47–100) points. In 9 of the 11 patients for whom treatment failed, infection was successfully treated with 1-stage or 2-stage reimplantation or resection. Intraoperative cultures were positive in 36 hips, and the most frequently isolated organisms were Staphylococcus aureus and coagulase-negative staphylococci (CoNS). 15 infections were polymicrobial, and only 8 of them were successfully treated with debridement and retention of the implant.Interpretation Our data suggest that debridement and retention of the prosthesis is a reasonable treatment option in early PJI after primary hip arthroplasty, with satisfactory functional results.

Early prosthetic joint infection: outcomes with debridement and implant retention followed by antibiotic therapy

Recent expert reviews recommend a conservative surgical strategy – debridement and irrigation, antibiotics and implant retention (DAIR) – for most early post-surgical prosthetic joint infections (PJI). However, differences exist in published series regarding success rates with DAIR, and the size of most series is small. In this prospective multicenter cohort study of early PJI managed by DAIR, factors associated with failure of the DAIR were analyzed. Out of 139 early PJI, 117 cases managed with DAIR were studied For 67 patients (57.3%), infection was cured and the implant was salvaged with definite antimicrobial therapy. In 35 (29.9%) DAIR failed and removal of the prosthesis was necessary during follow-up. Finally, 15 patients (12.8%) needed chronic suppressive antimicrobial therapy due to suspected or confirmed persistent infection. Infections due to methicillin-resistant S. aureus (72.7% failed; p 0.05) and those treated at one of the hospitals (80.0% failed; p <0.05) had worse outcomes, but only this last variable was associated with treatment failure following multivariate analysis. Seventy-four per cent of patients who were successfully treated by DAIR and only 32.7% of the failures were able to walk without help or with one stick at the last follow-up visit (p <0.05). In conclusion, a substantial proportion of patients with an early PJI may be successfully treated with DAIR and definite antimicrobial therapy. In more than half of these, the infection can be cured. Since identification of factors associated with failure of DAIR is not simple, we recommend offering DAIR to most patients with early PJI.

Efficacy of Debridement in Hematogenous and Early Post-Surgical Prosthetic Joint Infections

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. 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. 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. 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

To evaluate the relationship between intraoperative cultures during hip arthroplasty, the different patient characteristics, and the risk of developing a prosthetic joint infection (PJI). 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 peri- prosthetic tissue (S). Patients received standard antibiotic prophylaxis. The PJI rate within the first 3 months after arthroplasty was recorded. 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. 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.