Background: Propionibacterium acnes (P. acnes) is the most common bacteria associated with infection after shoulder arthroplasty. These bacteria can be grown on culture of skin after standard preoperative skin preparation and antibiotics. The purpose of this study was to determine whether adding preoperative intravenous doxycycline reduces the prevalence of positive P. acnes cultures of skin and deep tissues at the time of prosthetic joint implantation during shoulder arthroplasty. Methods: This was a randomized controlled trial. An a priori power analysis determined that a sample size of 56 patients was necessary. Patients scheduled to undergo shoulder arthroplasty were randomized to receive either standard perioperative cefazolin or a combination of doxycycline and cefazolin. Tissue specimens for culture were then taken from the skin edge, and swabs of the superficial dermal tissue and glenohumeral joint were obtained. All cultures were maintained for 14 days to allow for P. acnes detection. Groups were compared to determine if the addition of doxycycline reduced the rate of culture positivity. Results: Fifty-six patients were enrolled and randomized. Twenty-one (38%) had ≥1 positive cultures for P. acnes, with no significant difference between the group treated with cefazolin alone (10 [37%] of 27 patients) and the combined doxycycline and cefazolin group (11 [38%] of 29 patients) (p = 0.99). The greatest numbers of culture-positive samples were obtained from the skin (30%), followed by dermal tissue (20%) and the glenohumeral joint (5%). Patients who had ≥1 positive cultures were younger than those who did not (mean age [and standard deviation], 64.9 ± 7.7 versus 69.4 ± 7.7 years; p = 0.041), had a greater tendency to be male (16 [76%] of 21 versus 17 [49%] of 35; p = 0.053), and had a lower Charlson Comorbidity Index (3.35 ± 1.3 versus 4.09 ± 1.4; p = 0.051). There were no significant differences between the culture-positive and culture-negative groups in terms of body mass index (BMI) (p = 0.446) or arthroplasty type, with positive cultures found for 8 of the 29 anatomic shoulder arthroplasty procedures compared with 13 of the 27 reverse shoulder arthroplasty procedures (p = 0.280). There were no doxycycline-related adverse events. Conclusions: In this randomized controlled trial, doxycycline did not significantly decrease P. acnes culture positivity of the skin, dermis, or glenohumeral joint of patients undergoing shoulder arthroplasty. The addition of prophylactic intravenous antibiotics to cover P. acnes may not be an effective method to reduce postoperative and periprosthetic shoulder joint infections.

Background Periprosthetic joint infections (PJI) caused by pathogens, for which no biofilm-active antibiotics are available, are often referred to as difficult-to-treat (DTT). However, it is unclear whether the outcome of DTT PJI is worse than those of non-DTT PJI. We evaluated the outcome of DTT and non-DTT PJI in a prospective cohort treated with a two-stage exchange according to a standardized algorithm. Methods Patients with hip and knee PJI from 2013 to 2015 were prospectively included and followed up for ≥ 2 years. DTT PJI was defined as growth of microorganism(s) resistant to all available biofilm-active antibiotics. The Kaplan–Meier survival analysis was used to compare the probability of infection-free survival between DTT and non-DTT PJI and the 95% confidence interval (95% CI) was calculated. Results Among 163 PJI, 30 (18.4%) were classified as DTT and 133 (81.6%) as non-DTT. At a mean follow-up of 33 months (range 24–48 months), the overall treatment success was 82.8%. The infection-free survival rate at 2 years was 80% (95% CI 61–90%) for DTT PJI and 84% (95% CI 76–89%) for non-DTT PJI (p = 0.61). The following mean values were longer in DTT PJI than in non-DTT PJI: hospital stay (45 vs. 28 days; p < 0.001), prosthesis-free interval (89 vs. 58 days; p < 0.001) and duration of antimicrobial treatment (151 vs. 117 days; p = 0.003). Conclusions The outcome of DTT and non-DTT PJI was similar (80–84%), however, at the cost of longer hospital stay, longer prosthesis-free interval and longer antimicrobial treatment. It remains unclear whether patients undergoing two-stage exchange with a long interval need biofilm-active antibiotics. Further studies need to evaluate the outcome in patients treated with biofilm-active antibiotics undergoing short vs. long interval.

Spinal implant infection is a rare but significant complication of spinal fusion surgery, and the most common pathogen is Staphylococcus aureus. It is difficult to treat due to this pathogen's biofilm-forming ability and antibiotic resistance. We evaluated the therapeutic outcome of treatments for S aureus spinal implant infections. We retrospectively reviewed all patients with S aureus spinal implant infections at 11 tertiary-care hospitals over a 9-year period. Parameters predictive of treatment failure and recurrence were analyzed by Cox regression. Of the 102 patients with infections, 76 (75%) were caused by methicillin-resistant S aureus (MRSA) and 51 (50%) were late-onset infections. In all, 83 (81%) patients were managed by debridement, antibiotics, and implant retention (DAIR) and 19 (19%) had their implants removed. The median duration of all antibiotic therapies was 52 days. During a median follow-up period of 32 months, treatment failure occurred in 37 (36%) cases. The median time to treatment failure was 113 days, being <1 year in 30 (81%) patients. DAIR (adjusted hazard ratio [aHR], 6.27; P = .01) and MRSA infection (aHR, 4.07; P = .009) were independently associated with treatment failure. Rifampin-based combination treatments exhibited independent protective effects on recurrence (aHR, 0.23; P = .02). In conclusion, among patients with S aureus spinal implant infections, MRSA and DAIR were independent risk factors for treatment failure, and these risk factors were present in the majority of patients. In this difficult-to-treat population, the overall treatment failure rate was 36%; rifampin may improve the outcomes of patients with S aureus spinal implant infections.

Background Failed total knee arthroplasty (TKA) with significant bone loss and compromised soft-tissues is challenging and the final results are often inferior to patient’s expectation. The objective of this study was to present a comparison of outcomes in patients with failed infected TKA treated with two-stage revision TKA or knee arthrodesis and to assess clinical and functional results, implant survival and infection recurrence. The hypothesis was that an arthrodesis may result in beneficial effects on patients’ outcome. Methods Clinical data of 81 patients with periprosthetic joint infection (PJI) of the knee joint were collected and analyzed retrospectively. Between 2008 and 2014, a total of 36 patients had been treated within a two-stage exchange procedure and reimplantation of a modular intramedullary arthodesis nail and 45 patients with revision TKA. Patients were treated according to the same structured treatment algorithm. Clinical and functional evaluation was performed using the Oxford knee score (OKS) and the visual analogue scale (VAS). Results The mean follow-up was 32.9 ± 14.0 months. The rate of definitely free of infection at last follow-up in the arthrodesis group was 32 of 36 (88.9%) and 36 of 45 (80.0%) in the revision TKA group (p = 0.272). Mean VAS for pain in the arthrodesis group was 3.1 ± 1.4 compared to 3.2 ± 1.6 in the revision TKA group (p = 0.636). The OKS in the arthrodesis group was 38.7 ± 8.9 and 36.5 ± 8.9 (p = 0.246) in patients with revision TKA. Rate of revisions in the revision-TKA group was 2.8 ± 3.7 compared to 1.2 ± 2.4 in the arthrodesis group (p = 0.021). Conclusion Treatment of PJI needs a distinct therapy with possible fallback strategies in case of failure. A knee arthrodesis is a limb salvage procedure that showed no significant benefits on the considered outcome factors compared to revision TKA but is associated with significantly lower revision rate. After exhausted treatment modalities, a knee arthrodesis should be considered as an option in selected patients.

Aims Periprosthetic joint infection (PJI) remains a challenging complication following total hip arthroplasty (THA). It is associated with high levels of morbidity, mortality and expense. Guidelines and protocols exist for the management of culture-positive patients. Managing culture-negative patients with a PJI poses a greater challenge to surgeons and the wider multidisciplinary team as clear guidance is lacking. Patients and Methods We aimed to compare the outcomes of treatment for 50 consecutive culture-negative and 50 consecutive culture-positive patients who underwent two-stage revision THA for chronic infection with a minimum follow-up of five years. Results There was no significant difference in the outcomes between the two groups of patients, with a similar rate of re-infection of 6%, five years post-operatively. Culture-negative PJIs were associated with older age, smoking, referral from elsewhere and pre-operative antibiotic treatment. The samples in the culture-negative patients were negative before the first stage (aspiration), during the first-stage (implant removal) and second-stage procedures (re-implantation). Conclusion Adherence to strict protocols for selecting and treating culture-negative patients with a PJI using the same two-stage revision approach that we employ for complex culture-positive PJIs is important in order to achieve control of the infection in this difficult group of patients.

Fracture-related infection (FRI) is a common and serious complication in trauma surgery. Accurately estimating the impact of this complication has been hampered by the lack of a clear definition. The absence of a working definition of FRI renders existing studies difficult to evaluate or compare. In order to address this issue, an expert group comprised of a number of scientific and medical organizations has been convened, with the support of the AO Foundation, in order to develop a consensus definition. The process that led to this proposed definition started with a systematic literature review, which revealed that the majority of randomized controlled trials in fracture care do not use a standardized definition of FRI. In response to this conclusion, an international survey on the need for and key components of a definition of FRI was distributed amongst all registered AOTrauma users. Approximately 90% of the more than 2000 surgeons who responded suggested that a definition of FRI is required. As a final step, a consensus meeting was held with an expert panel. The outcome of this process led to a consensus definition of FRI. Two levels of certainty around diagnostic features were defined. Criteria could be confirmatory (infection definitely present) or suggestive. Four confirmatory criteria were defined: Fistula, sinus or wound breakdown; Purulent drainage from the wound or presence of pus during surgery; Phenotypically indistinguishable pathogens identified by culture from at least two separate deep tissue/implant specimens; Presence of microorganisms in deep tissue taken during an operative intervention, as confirmed by histopathological examination. Furthermore, a list of suggestive criteria was defined. These require further investigations in order to look for confirmatory criteria. In the current paper, an overview is provided of the proposed definition and a rationale for each component and decision. The intention of establishing this definition of FRI was to offer clinicians the opportunity to standardize clinical reports and improve the quality of published literature. It is important to note that the proposed definition was not designed to guide treatment of FRI and should be validated by prospective data collection in the future.

Background In total knee arthroplasty (TKA) periprosthetic joint infection (PJI), irrigation and debridement (I&D) with component retention is a treatment option with a wide variation in reported failure rates. The purpose of this study was to determine failure rates, outcomes, and factors that predict failure in I&D for TKA PJI. Methods A multicenter observational study of patients with a TKA PJI and subsequently undergoing an I&D with retention of components was conducted. The primary outcome was failure rate of I&D, where failure was defined as any subsequent surgical procedures. Results Two hundred sixteen cases of I&D with retention of components performed on 206 patients met inclusion criteria. The estimated long-term failure rate at 4 years was 57.4%. Time-to-event analyses revealed that the median survival time was 14.32 months. Five-year mortality was 19.9%. Multivariable modeling revealed that time symptomatic and organism were independent predictors of I&D failure. Culture-negative status had a higher hazard for failure than culture-positive patients. When primary organism and time symptomatic were selected to produce an optimized scenario for an I&D, the estimated failure rate was 39.6%. Conclusion I&D with retention of components has a high failure rate, and there is a high incidence of more complex procedures after this option is chosen. The patient comorbidities we investigated did not predict I&D success. Our results suggest that I&D has a limited ability to control infection in TKA and should be used selectively under optimum conditions.

BACKGROUND: One proposed strategy to increase the success of irrigation and debridement with implant retention for the treatment of acute periprosthetic joint infection (PJI) is the use of dissolvable antibiotic-impregnated calcium sulfate beads to provide a local depot of antibiotics. The purpose of this study was to evaluate the outcome of such an approach. METHODS: Thirty-two patients with acute hematogenous (18 patients; 1 bilateral) or acute postoperative (14 patients) PJIs who underwent irrigation and debridement with implant retention and addition of antibiotic-impregnated calcium sulfate beads were retrospectively reviewed. PJI followed 27 total knee arthroplasties and 6 total hip arthroplasties. The most common infecting organisms were methicillin-sensitive Staphylococcus aureus (13 of 33) and Streptococcus (9 of 33). The primary outcome parameter was recurrence of infection according to the Musculoskeletal Infection Society criteria. Patients were followed up for a minimum of 3 months or until failure. RESULTS: At a mean of 12.7 months (range, 3-30 months), 16 of the 33 patients failed (48%). Acute hematogenous and acute postoperative PJI had similar failure rates at 47% and 50%, respectively (P = .88). Seven failures required a 2-stage exchange, while 8 patients were treated with chronic antibiotic suppression, being unwilling or unable to undergo further surgical intervention. CONCLUSION: The addition of antibiotic-impregnated calcium sulfate beads does not appear to improve outcomes of irrigation and debridement with implant retention in the setting of acute hematogenous or acute postoperative PJI. Given the short follow-up in this report, this represents a best-case scenario and the overall failure rate may be higher with further follow-up.

Study Design. A retrospective, cohort study of 84 patients with deep spine infection managed at a major tertiary hospital over 14 years with a minimum follow up of 2 years. Objective. To determine the role of instrumentation in spines with deep infection. Summary of Background Data. It is often believed that implants should not be inserted in patients with deep spine infection because of the risk of persistent or recurrent infection. However, there are often concerns about spinal stability and a paucity of evidence to guide clinical practice in this field. Methods. We compared the mortality, reoperation, and reinfection rates in patients with spine infection treated with antibiotics alone, antibiotics with debridement, and antibiotics with debridement and instrumentation. Significant outcome predictors were determined using multivariable logistic regression model. Results. Forty-nine males and 35 females with a mean age was 62.0 years had spine infection affecting the lumbar spine predominantly. The most common form of infection was osteomyelitis and spondylodiscitis (69.4%). Staphylococcus aureus was the most common causative organism (61.2%). There was no difference in terms of reoperation or relapse for patients treated with antibiotics alone, antibiotics with debridement, or antibiotics with debridement and instrumentation. However, compared with antibiotics alone, the crude inhospital mortality was lower for patients treated with instrumentation (odds ratio, OR, 0.82; P = 0.01), and antibiotics with debridement (OR 0.80; P = 0.02). Conclusion. Spinal instrumentation in an infected spine is safe and not associated with higher reoperation or relapse rates. Mortality is lower for patients treated with instrumentation.

Background: Postoperative instrumented spine infection (PISI) is a severe complication of invasive spine procedures. Methods: Retrospective study of patients treated for PISI between 1st January 2008 and 31st December 2012 in a French University Hospital. The objectives of this study were to describe the outcome of patients treated with debridement-irrigation, antibiotic therapy and implant retention (DAIR) within three months after the occurrence of PISI and to identify factors associated with relapse. Results: Among 4290 patients who underwent spinal arthrodesis surgery during the 5-year study period, 129 had PISI treated by debridement-irrigation in the first three months (3.0%, 95% confidence interval [95%CI]: 2.5-3.5). Fifty-two (40%) were female and the median age was 57 years. Fourteen patients (10.8%) had diabetes and 73 (56.6%) had a BMI (Body Mass Index) ≥25 kg/m2. Staphylocccus aureus, enterobacteria or polymicrobial infections were identified in 44.0, 18.0 and 13.0% of cases, respectively. One hundred and six patients (82.2%) and one hundred and twenty-one patients (93.8%) were cured after one DAIR and after two DAIR, respectively. In multivariate logistic analysis, polymicrobial infection was associated with relapse (Odd Ratio [OR] = 3.81; 95%CI: 1.06-13.66; p = .03), while a BMI ≥25 kg/m2 was a protective factor (OR =0.25; 95%CI: 0.07-0.89; p = .03). Conclusion: DAIR may be effective for PISI when performed within the first 3 months after onset of infection. Relapses are significantly associated with polymicrobial infection and negatively associated with moderate overweight. These results need to be confirmed in future prospective studies.

Clinical and microbiological characteristics of patients with Bacteroides prosthetic joint infection (PJI) have not been well described in the literature. The aim of this retrospective cohort study was to assess the outcome of patients with Bacteroides PJI and to review risk factors associated with failure of therapy. Between 1/1969 and 12/2012, 20 episodes of Bacteroides PJI in 17 patients were identified at our institution. The mean age of the patients in this cohort at the time of diagnosis was 55.6 years; 59% (n=10) had knee involvement. Twenty four percent (n=4) had diabetes mellitus, and 24% had a history of either gastrointestinal (GI) or genitourinary (GU) pathology prior to the diagnosis of PJI. Thirty five percent (n=6) were immunosuppressed. The initial medical/surgical strategy was resection arthroplasty (n=9, 50%) or debridement and implant retention (n=5, 28%). Thirty seven percent (n=7) were treated with metronidazole. Eighty percent (n=4) of patients that failed therapy had undergone debridement and retention of their prosthesis, as compared to none of those treated with resection arthroplasty. Seventy percent (n=14) of patient episodes were infection free at their last date of follow up. In conclusion, a significant proportion of patients with Bacteroides PJI are immunosuppressed and have an underlying GI or GU tract pathology. Retention and debridement of the prosthesis is associated with a higher risk of treatment failure.

Discontinuing routine processing of screening urine cultures prior to elective joint arthroplasty resulted in substantial reduction in urine cultures ordered and antimicrobial prescriptions for asymptomatic bacteriuria, without any significant impact on incidence of prosthetic joint infection. This simple change would be scalable across institutions with potential for significant healthcare savings.

BACKGROUND: While periprosthetic joint infection (PJI) has a huge impact on patient function and health, only a few studies have investigated its impact on mortality. The purpose of this large-scale study was to (1) determine the rate and trends of in-hospital mortality for PJI and (2) compare the in-hospital mortality rate of patients with PJI and those undergoing revision arthroplasty for aseptic failure and patients undergoing other nonorthopedic major surgical procedures. METHODS: Data from the Nationwide Inpatient Sample from 2002 to 2010 were analyzed to determine the risk of in-hospital mortality for PJI patients compared with aseptic revision arthroplasty. The Elixhauser comorbidity index was used to obtain patient comorbidities. Multiple logistic regression analyses were used to examine whether PJI and other patient-related factors were associated with mortality. RESULTS: PJI was associated with an increased risk (odds ratio, 2.05; P < .0001) of in-hospital mortality (0.77%) compared with aseptic revisions (0.38%). The in-hospital mortality rate of revision total hip arthroplasties with PJI was higher than those for interventional coronary procedures (1.22%; 95% confidence interval [CI], 1.20-1.24), cholecystectomy (1.13%; 95% CI, 1.11-1.15), kidney transplant (0.70%; 95% CI, 0.61-0.79), and carotid surgery (0.89%; 95% CI, 0.86-0.93). CONCLUSION: Patients undergoing treatment for PJI have a 2-fold increase in in-hospital mortality for each surgical admission compared to aseptic revisions. Considering that PJI cases often have multiple admissions and that this analysis is by surgical admission, the risk of mortality will accumulate for every additional surgery. Surgeons should be cognizant of the potentially fatal outcome of PJI and the importance of infection control to reduce the risk of mortality.

Abstract. Fungal microorganisms are still a rare cause of bone and joint infections. We report a new case of knee prosthetic joint infection due to Candida albicans in a patient with a previous two-stage right knee arthroplasty for septic arthritis due to S. epidermidis occurred several months ago. Moreover, the treatment in 76 cases of Candida prosthetic joint infection has been discussed. Forty patients were female and mean age at diagnosis was 65.7 (± SD 18) yrs. No risk factors for candidal infection were found in 25 patients. Infection site was the knee in 38 patients and hip in 36; pain was present in 44 patients and swelling in 24. The most frequent species was C. albicans, followed by C. parapsilosis. Eleven patients were only treated with antifungal drugs being the outcome favourable in all of them. Two-stage exchange arthroplasty was performed in 30 patients, and resection arthroplasty in other 30; in three patients one-stage exchange arthroplasty was done. A favourable outcome was found in 58 patients after antifungal plus surgical treatment, in 11 after antifungal treatment alone and in one after surgery alone. The type of treatment is still not clearly defined and an algorithm for treatment in fungal PJI should be established, but various types of surgical procedures may be applied.

Background Implant-associated infections are still a feared complication in the field of orthopedics. Bacteria attach to the implant surface and form so-called biofilm colonies that are often difficult to diagnose and treat. Since the majority of studies focus on prosthetic joint infections (PJIs) of the hip and knee, current treatment options (eg, antibiotic prophylaxis) of implant-associated infections have mostly been adapted according to these results. Objective The aim of this study was to evaluate patients with surgical site infections following instrumented stabilization of the spine with regard to detected bacteria species and the course of the disease. Patients and methods We performed a retrospective single-center analysis of implant-associated infections of the spine from 2010 to 2014. A total of 138 patients were included in the study. The following parameters were evaluated: C-reactive protein serum concentration, microbiological evaluation of tissue samples, the time course of the disease, indication for instrumented stabilization of the spine, localization of the infection, and the number of revision surgeries required until cessation of symptoms. Results Coagulase-negative Staphylococcus spp. were most commonly detected (n=69, 50%), followed by fecal bacteria (n=46, 33.3%). In 23.2% of cases, no bacteria were detected despite clinical suspicion of an infection. Most patients suffered from degenerative spine disorders (44.9%), followed by spinal fractures (23.9%), non-degenerative scoliosis (20.3%), and spinal tumors (10.1%). Surgical site infections occurred predominantly within 3 months (64.5%), late infections after 2 years were rare (4.3%), in particular when compared with PJIs. Most cases were successfully treated after 1 revision surgery (60.9%), but there were significant differences between bacteria species. Fecal bacteria were more difficult to treat and often required more than 1 revision surgery. Conclusion In summary, we were able to demonstrate significant differences between spinal implant-associated infections and PJIs. These aspects should be considered early on in the treatment of surgical site infections following instrumented stabilization of the spine.