Camelia E. Marculescu

Outcome of Prosthetic Joint Infections Treated with Debridement and Retention of Components

BACKGROUND Debridement and retention of the prosthesis represents an attractive surgical modality for treatment of prosthetic joint infection, but risk factors for treatment failure require clarification. METHODS We conducted a retrospective cohort analysis of all patients with a prosthetic joint infection who were treated with debridement and retention of the prosthesis at the Mayo Clinic (Rochester, Minnesota) between 1995 and 1999. RESULTS Debridement and retention of the prosthesis was the initial treatment modality for 99 episodes of prosthetic joint infection that occurred in 91 patients who presented to the Mayo Clinic during 1995-1999. A total of 32% and 23% of all episodes were due to Staphylococcus aureus and coagulase-negative staphylococci, respectively. The median duration of intravenous antimicrobial therapy was 28 days (range, 1-90 days). Oral antimicrobial suppression was used in 89% of the episodes, for a median duration of 541 days (range, 5-2673 days). Treatment failure occurred in 53 episodes during a median follow-up period of 700 days (range, 1-2779 days). The 2-year survival rate free of treatment failure was 60% (95% confidence interval [CI], 50%-71%). Variables associated with an increased risk of treatment failure in multivariable analysis included the presence of a sinus tract (hazard ratio, 2.84; 95% CI, 1.48-5.44; P = .002) and a duration of symptoms prior to debridement of > or = 8 days (hazard ratio, 1.77; 95% CI, 1.02-3.07; P = .04). CONCLUSIONS Debridement and retention of the prosthesis is a common surgical modality at our institution to treat prosthetic joint infection. Risk factors independently associated with treatment failure include the presence of a sinus tract and duration of symptoms prior to debridement of > or = 8 days.

Culture-Negative Prosthetic Joint Infection

BACKGROUND Culture-negative (CN) prosthetic joint infection (PJI) has not been well studied. We performed a retrospective cohort study to define the demographic characteristics and determine the outcome of patients with CN PJI. METHODS All cases of CN total hip arthroplasty and total knee arthroplasty infections (using a strict case definition) treated at our institution from January 1990 through December 1999 were analyzed. Kaplan-Meier survival methods were used to determine the cumulative probability of success. RESULTS Of 897 episodes of PJI during the study period, 60 (7%) occurred in patients for whom this was the initial episode of CN PJI. The median age of the cohort was 69 years (range, 36-87 years). Patients had received a prior course of antimicrobial therapy in 32 (53%) of 60 episodes. Of the 60 episodes, 34 (57%), 12 (20%), and 8 (13%) were treated with 2-stage exchange, debridement and retention, and permanent resection arthroplasty, respectively. The median duration of parenteral antimicrobial therapy was 28 days (range, 0-88 days). Forty-nine (82%) of 60 episodes were treated with a cephalosporin. The 5-year estimate of survival free of treatment failure was 94% (95% confidence interval, 85%-100%) for patients treated with 2-stage exchange and 71% (95% confidence interval, 44%-100%) for patients treated with debridement and retention. CONCLUSIONS CN PJI occurs infrequently at our institution. Prior use of antimicrobial therapy is common among patients with CN PJI. CN PJI treated at our institution is associated with a rate of favorable outcome that is comparable to that associated with PJI due to known bacterial pathogens.

Outcome of enterococcal prosthetic joint infection: Is combination systemic therapy superior to monotherapy?

BACKGROUND The optimal medical or surgical therapy and outcome of enterococcal prosthetic joint infection are unknown. METHOD We performed a retrospective cohort study involving all patients with enterococcal total hip or knee arthroplasty infection treated at our institution from 1969 through 1999. The outcome for patients treated with combination systemic antimicrobial therapy (a cell wall-active agent and an aminoglycoside) versus monotherapy with a cell wall-active agent was analyzed. RESULTS Fifty episodes of prosthetic joint infection due to enterococci occurred in 47 patients. The median duration of follow-up was 1253 days (range, 29-4610 days). The median age at the time of diagnosis was 70 years (range, 32-89 years). Fifty percent of episodes (25 of 50 episodes) occurred in male patients; 48% (24 of 50 episodes) involved total hip or knee arthroplasty. The estimate of 2-year survival free of treatment failure was 94% (95% confidence interval [CI], 83%-100%) for patients treated with 2-stage exchange, 76% (95% CI, 58%-100%) for patients treated with resection arthroplasty, and 80% (95% CI, 51.6%-100%) for patients treated with debridement and retention of the components (P=.9). The overall rate of 2-year survival free of treatment failure was 88% (95% CI, 77%-100%) for patients treated with monotherapy and 72% (95% CI, 54%-96%) for patients treated with combination therapy (P=.1). The development of cranial nerve VIII toxicity was significantly more common among patients receiving combination therapy (P=.002). Nephrotoxicity was more frequent in the combination therapy group (occurring in 26% of episodes; P=.09). CONCLUSIONS Enterococcal prosthetic joint infection is uncommon at our institution. Patients receiving combination therapy and those receiving monotherapy did not differ with respect to outcome. There were more cases of ototoxicity in the combination therapy group than there were in the monotherapy group.

Prevention of Infection in Orthopedic Prosthetic Surgery

Total joint arthroplasty is a generally safe orthopedic procedure; however, infection is a potentially devastating complication. Multiple risk factors have been identified for development of prosthetic joint infections. Identification of patients at risk and preoperative correction of known risk factors, such as smoking, diabetes mellitus, anemia, malnutrition, and decolonization of Staphylococcus carriers, represent well-established actions to decrease the infection risk. Careful operative technique, proper draping and skin preparation, and appropriate selection and dosing of antimicrobials for perioperative prophylaxis are also very important in prevention of infection.

Management of prosthetic joint infection treated with two-stage exchange: the impact of antimicrobial therapy duration

BackgroundThe optimal duration of parenteral antimicrobial therapy in patients with prosthetic joint infection treated with a two-stage exchange is unknown. MethodsThis analysis compares the outcomes between patients treated with 4 weeks and those treated with 6 weeks of parenteral antimicrobial therapy after a two-stage exchange for prosthetic joint infection. The medical records of all patients with total knee arthroplasty or total hip arthroplasty infections treated with a two-stage exchange between 1995 and 1999 at our institution were reviewed. Cox regression models were used to compare treatment failure rates between patients who were treated for 4 weeks and those who were treated for 6 weeks with antimicrobial therapy after adjusting for the propensity to be treated for 6 weeks. ResultsTwo hundred and eight prosthetic joint infections occurred in 201 patients. Thirty-nine percent and 61% of prosthetic joint infections were treated with 4 weeks or 6 weeks of parenteral antimicrobials, respectively. The 5-year success rate was 84% and 73% in the 4-week and 6-week groups, respectively. After adjusting for the propensity to be treated for 6 weeks, there was no significant differences in the treatment failure rates between those treated with 6 weeks of parenteral antimicrobials and those treated with 4 weeks [hazard ratio (HR)=1.4, 95% confidence interval (CI), 0.7-2.7; P=0.31]. ConclusionsSix weeks of parenteral antimicrobials between stages did not decrease the treatment failure rate in patients with prosthetic joint infections compared with 4 weeks of treatment.

Septic Arthritis and Osteomyelitis

Septic arthritis and osteomyelitis are two of the most common diseases that affect bone and joints. Septic arthritis is a true rheumatologic emergency, mandating immediate joint drainage and antibiotics. Adult osteomyelitis most commonly arises from open fractures, diabetic foot infections, or surgical treatment of closed injuries. This chapter provides an overview of the etiology, diagnosis, and antimicrobial management of septic arthritis and adult osteomyelitis.

A Case of Malaria Predisposing to Salmonella Bacteremia in a Returning Traveler from Nigeria

We describe a febrile adult returning to the U.S. from Nigeria. Malaria was diagnosed by rapid antigen testing, but recognition of invasive nontyphoidal Salmonella disease was delayed. While the moniker, “typhomalaria,” once used to describe an illness with features of malaria and typhoid fever, has fallen out of favor, it may nevertheless be a helpful reminder to clinicians that both infectious diseases can arise in the same patient. Blood cultures should be obtained routinely in febrile returning travelers from malaria-endemic regions, including those in whom the diagnosis of malaria has already been established.

Peripherally inserted central catheter–associated bloodstream infection: Risk factors and the role of antibiotic-impregnated catheters for prevention

HIGHLIGHTSLarge retrospective nested case control study characterized risk factors for peripherally inserted central catheters (PICC) blood stream infections (BSI).PICC‐associated BSIs were highest among patients receiving nonimpregnated catheters in this large study.Highest risk for PICC‐related BSIs occurred with placement of a tunneled catheter, AIDS, leukemia, and whether the indication for a peripherally inserted central catheter was chemotherapy.Antimicrobial‐impregnated PICCs should be considered in all patients receiving peripherally inserted central lines. Background: Antimicrobial‐impregnated (AIP) peripherally inserted central catheters (PICCs) may lower risk of central line‐associated bloodstream infection (CLABSI) compared with nonantimicrobial‐impregnated (NAIP) catheters. We sought to assess risk factors for CLABSI with a focus on the effect of AIP PICCs. Methods: CLABSI rate was determined among patients who received PICCs from July 2009 through June 2012 using a retrospective study design. A nested case‐control study matched for operators (interventional radiology [IR], infectious diseases [IDs], and the nurse venous access team [VAT]) was conducted to assess risks for PICC CLABSI. Results: Eighty‐nine PICC CLABSIs (1.66%) occurred among 5,372 PICC placements a mean of 32 days after placement. Higher infection risk (1.75) was observed for IR‐placed PICCs compared with ID‐placed PICCs (P=.02). In addition, higher infection risk (4.22) was observed for IR‐placed PICCS compared with VAT‐placed PICCs (P=.0008). IR‐placed NAIP catheters, as indicated by multivariate analysis, revealed a 5.45‐fold greater CLABSI risk compared with AIP catheters (P < .0005). Other risk factors included chemotherapy, placement of a tunneled catheter, leukemia, and AIDS. Conclusions: PICC CLABSIs were highest among patients receiving NAIP catheters in this large study. Highest risk occurred with placement of a tunneled catheter, AIDS, leukemia, and if the indication for PICC was chemotherapy. Our study suggests that the AIP PICC should be considered in all patients receiving PICCs.

Editorial Comment: Symposium: 2014 Musculoskeletal Infection Society

T he annual meeting of the Musculoskeletal Infection Society serves as a forum for presentation of novel research work, education, and promotion of fruitful discussion and collaboration among participants. The manuscripts included in this symposium, which were presented at the 2014 meeting, underwent formal, rigorous peer review and present interesting and important findings spanning the topics of diagnosis, treatment, and prevention of musculoskeletal infections. Periprosthetic joint infection (PJI) is often challenging to diagnose with the currently available methods. The use of synovial fluid biomarkers, such as alpha-defensin, is an exciting new development that has shown promise in the diagnosis of PJI and provides consistent results regardless of the microorganisms present. This is important since microorganisms of low virulence may not produce an inflammatory response. On the other hand, a periprosthetic fracture may create such a response, thereby confounding the diagnostic attempt to determine if a PJI is also present. Administration of antibiotics is another confounding variable that reduces the laboratory values indicative of PJI and hinders diagnosis of this complication. These and other limitations of current diagnostic methods should always be kept in mind by the treating physicians [2]. Further research on developing new methods and improving the use of current ones is needed to refine the diagnostic process, but we are proud to present some important findings on these key issues in these proceedings. Treatment of musculoskeletal infections often includes the local administration of antimicrobials using various delivery vehicles, such as bone