Non-gonococcal septic arthritis of native joints in Western Australia. A longitudinal population-based study of frequency, risk factors and outcome.

OBJECTIVE: To describe the incidence and long-term outcome of non-gonococcal septic arthritis (SA) in Western Australia (WA). METHODS: Newman criteria were applied to define culture-positive SA and suspected SA cases in the state-wide West Australian Rheumatic Diseases Epidemiological Registry with longitudinally linked health data for patients >16 years with a first diagnostic code of pyogenic arthritis (711.xx [ICD-9-CM] and M00.xx [ICD-10-AM]) between 1990-2010. Annual incidence rates/100 000 (AIR) and standardized (against WA population) mortality rates/1000 person-years (SMR) and outcomes during 10.1 years follow-up are reported. RESULTS: Among 2633 SA patients (68.6% male, age 47.4 years), 1146 (43.5%) had culture-positive SA. The overall AIR for culture-positive (1.6-6.3) and total SA cases (4.3-12.9) increased between 1990 and 2010 as did age at onset (39.5-54 years) and proportion of females (23-35.6%). Knees (33.6.%) were most frequently affected and 37.1% of cultures showed microorganisms other than Gram-positive cocci. Thirty-day rates for readmission and mortality were 25.4% and 3.2.%. During follow-up rates for serious infections (56.4%), osteoarthrosis (5.2%) and osteomyelitis (2.7%) were higher in culture-positive SA. SMR was increased for all SA patients but especially in those 17-40 years of age with culture-positive SA (24.2; 95% CI 2.3-261). CONCLUSIONS: The incidence of SA in WA has risen steeply over 20 years. SA now occurs at higher age, affects females more often with over a third of cases caused by Gram-negative microorganisms. Not only culture-positive, but also suspected SA led to increased bone/joint complications, in-hospital and late mortality.

Patients with surgically treated culture-negative native joint septic arthritis have less severe disease and better outcomes.

Background: Patients with culture-negative septic arthritis patients are often treated surgically but might be successfully managed medically. We compared clinical characteristics and outcomes in patients with culture negative and culture positive native joint monoarticular septic arthritis.Methods: This retrospective study included all patients age ≥18 years admitted to a single, tertiary-care hospital between 1998 and 2015 with native joint monoarticular SA and treated with antibiotics and surgery.Results: Of 306 patients, 85 had negative and 221 had positive cultures. Mean C-reactive protein (p < .01) and mean percentage of peripheral polymorphonuclear cells (p = .01) were higher in culture-positive patients who had higher intensive care unit admission rates (16.7% vs. 4.7%, respectively, [p < .01]), longer length of hospital stay (11.4 vs. 7.1 days, respectively, [p < .01]) and higher mortality rates within 30 days (0% vs. 5.5%, respectively,[p = .02]). Of culture-negative patients, 28.6% received an alternative diagnosis within one year. Logistic regression models showed that culture positive patients had an adjusted odds ratio for length of stay of 4.5 (2.69, 7.51), intensive care unit admission of 5.76 (1.31, 25.22), discharge to rehabilitation of 4.7 (2.28, 9.71) and an alternative diagnosis within one year of 0.05 (0.02, 0.15) compared to culture negative patients.Conclusion: Patients with culture-negative native joint septic arthritis had less severe disease, better outcomes and higher rates of alternative diagnosis within one year than patients with positive cultures.

Site-specific mortality in native joint septic arthritis: a national population study.

OBJECTIVE: This national cohort study investigated the incidence, site-specific mortality and prognostic factors of native septic arthritis (SA). METHODS: Tapping Taiwan's National Health Insurance Research Database, we identified inpatients with newly diagnosed SA between 1998 and 2012. They were categorized by site of infection and followed to calculate 30-day, 90-day and 1-year mortality. Predictors of mortality were calculated using Cox models. RESULTS: A total of 31 491 patients were identified as having SA, the most common site of infection being the knee (50.1%), followed by the hip (14.4%), other sites (26.8%), the shoulder (5.5%) and multiple sites (1.2%). Knee joint involvement was the most common site for all subgroups. Incidence increased from 9.8/105 in 1998 to 13.3/105 in 2012. The 30-day, 90-day and 1-year mortality rates were 4.3, 8.6 and 16.4% respectively. Predictors for mortality were hip infection, shoulder infection, multiple-site infection, being male, age ≥65 years old and comorbidities. We derived a mortality scoring model over age/SA site/comorbidity, and age ≥65 years old had the greatest risk contribution to mortality. No matter whether 1-month, 3-month or 1-year mortality was being considered, patients with the higher risk scores had the higher mortality rates (P < 0.0001). CONCLUSION: SA is an emerging infectious disease with a rising incidence, long duration of hospital stay and high mortality rate. The most common affected joint was knee for all subgroups. Patients aged ≥65 years old had a high SA incidence and the greatest risk contribution.

The role of Staphylococcus aureus lipoproteins in hematogenous septic arthritis.

Permanent joint dysfunction is a devastating complication in patients with septic arthritis. Staphylococcus aureus (S. aureus) lipoproteins (Lpp), the predominant ligands for TLR2, are known to be arthritogenic and induce bone destruction when introduced directly into the joint. Here, we aim to investigate the importance of S. aureus Lpp and TLR2 in a hematogenous septic arthritis model, which is the most common route of infection in humans. C57BL/6 wild-type and TLR2 deficient mice were intravenously inoculated with S. aureus Newman parental strain or its lipoprotein-deficient Δlgt mutant strain. The clinical course of septic arthritis, radiological changes, and serum levels of cytokines and chemokines, were assessed. Newman strain induced more severe and frequent clinical septic polyarthritis compared to its Δlgt mutant in TLR2 deficient mice, but not in wild-type controls. Bone destruction, however, did not differ between groups. Lpp expression was associated with higher mortality, weight loss as well as impaired bacterial clearance in mouse kidneys independent of TLR2. Furthermore, Lpp expression induced increased systemic pro-inflammatory cytokine and neutrophil chemokine release. Staphylococcal Lpp are potent virulence factors in S. aureus systemic infection independent of host TLR2 signalling. However, they have a limited impact on bone erosion in hematogenous staphylococcal septic arthritis.

Hospital Stays and Medical Expenses Increase Nationwide Among Patients With Septic Arthritis of the Shoulder Who Inject Drugs.

The authors determined the proportion of patients nationwide with septic arthritis of the shoulder who inject drugs, evaluated differences in hospitalization outcomes and charges between patients with and without injection drug use (IDU), and quantified demographic trends among patients with IDU from 2000 to 2013. Nationally representative data of patients with a principal discharge diagnosis of shoulder septic arthritis were obtained from the Nationwide Inpatient Sample 2000-2013. Using published algorithms, the authors classified septic arthritis of the shoulder as related or unrelated to IDU. They compared length of stay, leaving against medical advice, number of procedures, and mortality rates between the 2 groups, using regression models to control for age, sex, and race. Fifteen percent (95% confidence interval [CI], 13.6%-16.5%) of septic arthritis cases were associated with IDU. From 2000 to 2013, shoulder septic arthritis associated with IDU increased 4-fold. After controlling for age, sex, and race, individuals who inject drugs stayed in the hospital for 3.7 more days (95% CI, 2.4-5.0), incurred an average of $13,250 more charges for medical care (95% CI, $2635-$23,866), and were 5.54 times more likely (95% CI, 3.22-9.55) to leave against medical advice than those without IDU. From 2000 to 2013, there was an increase in the proportion of patients with IDU-related septic arthritis of the shoulder between 35 and 54 years old and 55 and 64 years old, and an increase in the proportion who were white. Injection drug use-related shoulder septic arthritis is linked to suboptimal inpatient outcomes and greater resource use. [Orthopedics. 2020;43(4):e270-e277.].

Clinical characteristics and outcomes of patients with septic arthritis treated without surgery.

Septic arthritis (SA) is typically managed with antibiotic therapy with or without surgery. Little is known about how patients without surgery differ from their operatively managed counterparts. We compared SA patients who received antibiotic treatment with and without surgery. We conducted a retrospective study of patients with monoarticular septic arthritis admitted to a single tertiary care centre between 1998 and 2015. All 441 monoarticular septic arthritis patients received antibiotics; 382 were also managed operatively and 59 nonoperatively. Nonoperative patients were older (64.4 vs 58.3 years old; p = 0.02) and less likely to have prior joint pathology (44.1% vs 67.5%; p < 0.001). Nonoperative patients presented more often with sepsis (37.3% vs 31.9; p = 0.02) and were more frequently admitted to the intensive care unit (23.7% vs 16.5%; p = 0.04). Nonoperative patients were less often discharged to a rehabilitation facility (37.9% vs 55.8%; p = 0.002) and less frequently readmitted to hospital within 60 days of initial discharge (15.3% vs 18.6%; p = 0.05). However, nonoperative patients were more likely to expire within 30 days after hospital discharge (11.9% vs 3.9%; p = 0.009). Nonoperative patients were sicker at presentation; despite deferral of surgery, they had a relatively high survival rate (88%). Among survivors whose data was available, there were no significant sequelae in post-discharge imaging. These findings support the nonsurgical approach as effective for patients with septic arthritis who are not critically ill at time of presentation.

Sternoclavicular Joint Infections: Improved Outcomes With Myocutaneous Flaps.

Sternoclavicular joint (SCJ) infection is a rare disease and its management remains controversial. Our institution has adopted an aggressive surgical approach of radical SCJ resection combined with myocutaneous flap (MCF) closure whenever possible. We reviewed our experience with this approach in the management of this condition. From July 2004 to June 2018, 50 consecutive patients were treated surgically for SCJ infections. Patient demographics, imaging studies, microbiology, and operative variables were analyzed. All patients underwent ipsilateral SCJ resection. Wound closure was performed with primary pectoralis advancement MCF closure at the initial operation in 25 patients, delayed MCF closure following temporary wound vacuum therapy and redebridement in 19 patients, and definitive wound vacuum therapy (DWVT) in 6 patients. End points were recurrence of infection, perioperative morbidity, and mortality. Localized swelling (100%) and pain (100%) were the most common presenting symptoms. MSSA was isolated in 50% of tissue cultures. Comorbidities included tobacco smoking 52%, diabetes mellitus 50%, intravenous drug use 34%, poor dental hygiene 32%, and obesity 28%. We had no deaths within 90 days of operation. Complications; seroma in 1 patient (2%), chest wall hernia in 1 patient (2%), retained drains in 1 patient (2%), recurrent osteomyelitis infection in 3 patients (6%), and hematomas in 5 patients (10%). Patients treated with primary MCF closure at the initial operation had a 0% (0/25) rate of recurrence compared to 5.26% (1/19) in delayed MCF closure. Overall, there was only a 2.27% (1/44) recurrence of infection in primary and delayed MCF closure combined, compared to 33.33% (2/6) in patients treated with DWVT closure. SCJ infections require an aggressive approach. Wound closure with an MCF (primary or delayed) is associated with less recurrence of infections compared with DWVT closure. Radical resection of the entire SCJ with MCF (primary or delayed) should be considered the preferred management strategy in patients with SCJ infections.

Incidence and Characteristics of Osteoarticular Infections in Patients With Infective Endocarditis.

Osteoarticular infections (OAIs) in the setting of infective endocarditis (IE) are uncommon. Although morbidity and mortality have been widely studied, details of the characteristics of patients with concurrent IE and OAI are limited. Therefore, the purpose of this study was to determine the (1) incidence, (2) mortality, (3) clinical features, and (4) microbiological profiles of OAIs in the setting of IE. A retrospective review was conducted of 1280 IE cases at a large academic institution between 2009 and 2015. Patients were categorized according to the following OAI types: spondylodiskitis, large joint septic arthritis, other site infections, or multiple affected joints. Inpatient mortality rates, clinical findings, and microbiological characteristics were compared between OAI types. Overall, the incidence of OAI among IE patients was 6.8% (n=87). The in-hospital mortality rate was 9.2% (n=8) and was not significantly associated with OAI type (P=.801). Eighteen patients had multiple affected joints resulting in a total of 114 infected sites. Of these, 39% (n=44) were spondylodiskitis, 29% (n=33) were large joint septic arthritis, and 32% (n=37) were infections of smaller joints. Back pain was most common among patients with spondylodiskitis (P<.001), whereas fever and general fatigue were most common with septic arthritis (P<.001). Of the available bone/ joint cultures, 69% were positive. Overall, Staphylococcus aureus was the most common IE pathogen in patients with both IE and OAI (63%). Clinicians should maintain a high suspicion for OAI in patients with IE caused by Staphylococcus aureus, particularly spondylodiskitis among those presenting with back pain. [Orthopedics 2020; 43(1):24-29.].

Mortality and adverse joint outcomes following septic arthritis of the native knee: a longitudinal cohort study of patients receiving arthroscopic washout.

BACKGROUND: The short-term and long-term consequences of septic arthritis are uncertain. We aimed to determine risk of mortality and adverse joint outcomes following septic arthritis of the native knee. METHODS: We did a retrospective cohort study in patients who received arthroscopic knee washout for septic arthritis in England between April 1, 1997, and March 31, 2017, using data in the national Hospital Episode Statistics database. Patients with previous knee surgery to the same knee were excluded. Mortality within 90 days, adverse joint outcomes (arthrodesis, amputation, arthroplasty) within 1 year, and arthroplasty within 15 years were determined. Mortality in patients with a primary admitting diagnosis of septic arthritis (ICD-10) was compared with that in patients in whom septic arthritis was a secondary diagnosis. FINDINGS: 12 132 patients were included (mean age 56·6 years [SD 24·9]) of whom 4307 (36%) were female. In 10 195 (84%) patients with septic arthritis as the primary admitting diagnosis, 90-day mortality was 7·05% (95% CI 6·56-7·57; 719 patients), rising to 22·69% (20·80-24·68; 418 patients) in 1842 patients older than 79 years. Secondary septic arthritis diagnosis versus primary diagnosis was associated with an adjusted odds ratio for mortality of 2·10 (95% CI 1·79-2·46; p<0·0001). In 11 393 patients with at least 1 year follow-up, the 1 year rates were 0·13% (95% CI 0·07-0·22; 15 patients) for arthrodesis, 0·40% (0·30-0·54; 46 patients) for amputation, and 1·33%; (1·13-1·56; 152 patients) for arthroplasty. Within 15 years, 159 (8·76%; 95% CI 7·50-10·15) of 1816 patients had received arthroplasty, corresponding to an annual risk of arthroplasty that was about six times that of the general population (risk ratio 6·14, 95% CI 4·95-7·62; p<0·0001). INTERPRETATION: The consequences of septic knee arthritis in patients undergoing arthroscopic knee washout are serious. These findings highlight the potentially devastating outcomes associated with sepsis from musculoskeletal joint infection. FUNDING: National Institute for Health Research.

A novel mouse model for septic arthritis induced by Pseudomonas aeruginosa.

Septic arthritis is one of the most aggressive joint diseases. Although caused predominantly by S. aureus, Gram-negative bacteria, Pseudomonas aeruginosa among them, account for a significant percentage of the causal agents of septic arthritis. However, septic arthritis caused by P. aeruginosa has not been studied thus far, due to lack of an animal model. NMRI mice were inoculated with different doses of P. aeruginosa. The clinical course of septic arthritis and radiological changes of joints were examined. Furthermore, the host molecular and cellular mechanisms involved in P. aeruginosa-induced septic arthritis were investigated. Inoculation of mice with P. aeruginosa caused septic arthritis in a dose-dependent manner. Neutrophil depletion led to higher mortality and more severe joint destruction (p < 0.01). In contrast, monocyte depletion resulted in higher mortality (p < 0.05) but similar arthritis severity compared to controls. Mice depleted of CD4+ T-cells inoculated with P. aeruginosa displayed less severe bone damage (p < 0.05). For the first time, a mouse model for P. aeruginosa septic arthritis is presented. Our data demonstrate that neutrophils play a protective role in P. aeruginosa septic arthritis. Monocytes/macrophages, on the other hand, are only essential in preventing P. aeruginosa-induced mortality. Finally, CD4+ T-cells are pathogenic in P. aeruginosa septic arthritis.

High 2-year mortality and recurrent infection rates after surgical treatment for primary septic arthritis of the hip in adult patients: An observational study.

Primary septic arthritis of the hip is rare and potentially devastating in adults. Its optimal surgical treatment and clinical outcomes remain unclear.In this retrospective cohort study, we investigated mortality and reinfection rates after surgery of patients with septic hip arthritis. We reviewed patients treated for primary septic hip joints from October 2005 to December 2016. A total of 51 adult patients were identified, and 38 among them had destructive hip joints. A poor postoperative outcome was defined as mortality or recurrent infection within 2 years of surgery.After surgery, 7 (13.7%) patients died within 1 year and 5 (9.8%) patients developed a recurrent hip infection within 2 years. Therefore, poor outcomes occurred in 22% (n = 11) of the study cohort. Among the 38 patients with a destructive hip joint, 7 (18.4%) died within 1 year after surgery and 4 (10.5%) developed a recurrent hip infection within 2 years of surgery. Correlative infections other than infected hip joint and liver cirrhosis were identified as risk factors for poor outcomes.In conclusion, clinical physicians treating adult primary septic hip joints should be cognizant of the high failure rate of surgical treatment. In addition, the high mortality rate should be considered during the discussion of surgical treatment with these patients and their families.

Long-term antimicrobial suppression prevents treatment failure of streptococcal periprosthetic joint infection.

OBJECTIVES: To evaluate the effect of oral antimicrobial suppression on the outcome of streptococcal periprosthetic joint infection (PJI). METHODS: Consecutive patients with streptococcal PJI receiving antimicrobial suppression for >6 months were prospectively included and compared to a retrospective control group without suppression. Outcome was assessed with Kaplan-Meier analysis and compared by the log-rank Mantel-Cox test. Multivariate analysis was used to identify factors associated with treatment failure. RESULTS: Of 69 streptococcal PJI episodes (37 knee, 31 hip and one shoulder PJI), 43 (62%) were caused by beta-hemolytic streptococci and 26 (38%) by viridans group streptococci. Debridement and prosthesis retention was performed in 27 (39%), one-stage exchange in 5 (7%), multi-stage exchange in 31 (44%) and prosthesis removal in 6 patients (9%). 24 patients (35%) were treated with antimicrobial suppression receiving oral amoxicillin (n = 22), doxycycline (n = 1) or clindamycin (n = 1). After a median follow-up of 13 months (range, 0.5-111 months), 38 of 65 patients (58%) were infection-free. Suppressive antimicrobial treatment was associated with higher success rate compared with no suppression (93% vs. 57%, p = 0.002), representing the only significant independent factor preventing treatment failure. CONCLUSIONS: Long-term antimicrobial suppression was associated with significantly better treatment outcome and should be strongly considered in streptococcal PJI.

Clinical manifestations and outcomes of musculoskeletal nontuberculous mycobacterial infections.

To investigate the clinical manifestations and outcomes of musculoskeletal (MSK) nontuberculous mycobacterium (NTM) infections. This study was a retrospective cohort study using the Siriraj Hospital database from 2005 to 2017. Enrolled were all patients aged 15 or older who had an MSK infection with NTM identified in synovial fluid, pus, or tissue by an acid-fast bacilli stain, culture, or polymerase chain reaction. Of 1529 cases who were diagnosed with NTM infections, 39 (2.6%) had an MSK infection. However, only 28 patients met our inclusion criteria. Their mean age (SD) was 54.1 (16.1) years, and half were male. Of this cohort, 25% had previous musculoskeletal trauma, 18% prior bone and joint surgery, 14% prosthetic joint replacement, and 11% HIV infection. The median symptom duration (IQR) was 16 (37.4) weeks. The most common MSK manifestation was arthritis (61%), followed by osteomyelitis (50%), tenosynovitis (25%), and spondylodiscitis (14%). The most common organism was M. abscessus (18%), and M. kansasii (18%), followed by M. intracellulare (14%), M. marinum (14%), M. fortuitum (7%), and M. haemophilum (7%). In addition to medical treatment, most patients underwent surgery (82%), comprising debridement, osteotomy, prosthesis removal, and amputation, while 18% received only medical treatment. The treatment outcomes were complete recovery in 46%, improvement with some residual disability and deformities in 29%, and death in 3.6%. Musculoskeletal NTM infections were uncommon. Most patients had underlying joint disease or were immunocompromised hosts. Surgical management, as an adjunct to medical therapy, was necessary.

Clinical features of patients with septic arthritis and echocardiographic findings of infective endocarditis.

PURPOSE: Patients with septic arthritis (SA) often undergo echocardiographic evaluation to identify concomitant infective endocarditis (IE). The purpose of this study is to identify distinguishing features of patients with SA and IE by comparing them to patients with SA alone. METHODS: We conducted a retrospective study of all patients 18 and older admitted to a single tertiary hospital between 1998 and 2015 with culture-positive SA. Patients were stratified by echocardiogram status and the presence of vegetations: those who had echocardiographic evaluation with no evidence of infective endocarditis (ECHO + IE-) or with a vegetation present (ECHO + IE+) and those who had no echocardiographic evaluation (ECHO-). Demographic data, clinical characteristics, microbiology data, treatment strategies, and patient outcomes were recorded and compared. RESULTS: We identified 513 patients with SA. Transthoracic echocardiogram and/or transesophageal echocardiogram were performed in 263 patients (51.2%) and demonstrated evidence for IE in 19 patients (3.7%). While most demographic features, comorbidities, and clinical characteristics did not differ significantly between those with and without IE, those with IE had higher rates of sepsis and septic shock. In addition, patients with SA and IE had higher rates of positive blood cultures and Methicillin-sensitive staphylococcus aureus (MSSA) infection when compared to those with SA without IE. Patients with IE had higher rates of intensive care unit admission and increased 30-day mortality. CONCLUSIONS: IE is uncommon among patients with SA. Echocardiography may be overutilized and may be more useful among patients presenting with sepsis, shock, or positive blood cultures, especially when MSSA is isolated.

Septic arthritis due to streptococci and enterococci in native joints: a 13 year retrospective study.

OBJECTIVES: Streptococcal species are the second most common cause of native joint septic arthritis (SA). However, there are few systematic data about streptococcal SA. METHODS: The medical records of adults with SA caused by streptococci, pneumococci, and enterococci at our tertiary care centre between 2003 and 2015 were reviewed. RESULTS: 71 patients (34% female) with 83 affected joints were included. Median age was 62 years. A single joint was involved in 62 patients (87%). One or more comorbidities were present in 58 patients (82%). 16 patients (23%) had a concomitant soft-tissue infection overlying the affected joint. The hematogenous route was the dominating pathogenesis (42/71, 59%). 9 (13%) patients were diagnosed with endocarditis. The knee was the most commonly affected joint (27/83, 33%) followed by shoulder (13/83, 16%). ß-haemolytic streptococci were most commonly identified (37/71, 52%) followed by polymicrobial infections (12/71, 17%). Surgical interventions included arthroscopic irrigation and debridement in 31 (44%), arthrotomy in 23 (32%), and amputation in five patients (7%). Median duration of antimicrobial therapy was 42 days. Antibiotic treatment without any surgical intervention was performed in 5 (7%) patients. Outcome was good in 55 (89%) patients; mortality was 13% with four of nine deaths attributed to joint infection. Age and pathogen group independently predicted poor outcome in recursive partitioning analysis. CONCLUSIONS: Streptococcal SA was mostly due to ß-haemolytic streptococci in older and polymorbid patients. Old age, anginosus group streptococci, enterococci, and polymicrobial infections predicted poor outcome, while antibiotic treatment duration can likely be shortened.

Mortality During Total Hip Periprosthetic Joint Infection.

BACKGROUND: We sought to understand the mortality rate of periprosthetic joint infection (PJI) of the hip undergoing 2-stage revision for infection. METHODS: Database search, yielding 23 relevant studies, totaled 19,169 patients who underwent revision for total hip PJI. RESULTS: One-year weighted mortality rate was 4.22% after total hip PJI. Five-year mortality was 21.12%. Average age was 65 years. When comparing the national age-adjusted risk of mortality and the reported 1-year mortality risk in this systematic review, the risk of death after total hip PJI is significantly increased (odds ratio 3.58, P < .001). CONCLUSION: The mortality rate during total hip revision for infection is high. When counseling a patient regarding complications of this disease, death should be discussed.

Factors Related to Surgical Treatment and Outcomes of Thai Patients With Septic Arthritis.

OBJECTIVE: The aim of this study was to identify factors associated with the surgical treatment of Thai patients with septic arthritis. METHODS: This cohort study used a university hospital database in Thailand to identify 450 adult patients with confirmed septic arthritis. Data related to baseline characteristics, clinical and laboratory findings, treatment, and outcomes were collected. A multivariate analysis identified the factors related to surgical treatment. RESULTS: The patients had a mean age (±SD) of 53.6 (±17.8) years, and 51% were male. Surgical drainage was performed on 332 patients (74%). The factors identifed as relating to the need for surgical drainage included preexisting joint disease (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.3-4.9), hip involvement (OR, 36.3; 95% CI, 4.1-320.5), abscess formation (OR, 5.6; 95% CI, 1.1-27.1), osteomyelitis (OR, 4; 95% CI, 1.1-14.9), and positive synovial fluid culture (OR, 3.8; 95% CI, 2-7.2). In contrast, patients who were treated with steroids (OR, 0.2; 95% CI, 0.1-0.4) or had septic shock (OR, 0.31; 95% CI, 0.13-0.83) were less likely to undergo surgery. This model correctly predicted 35% of cases. Patients treated with surgical drainage had a significant longer length of stay (median [interquartile range], 21 [11-34] days vs 14 [7-24] days; p < 0.0001) and were less likely to achieve complete recovery (26% vs 53%, p < 0.0001). However, the mortality rate was lower (2.4% vs 10.2%). CONCLUSIONS: Patients with septic arthritis who had underlying joint disease, hip involvement, abscess formation, osteomyelitis, and organisms in their synovial fluid were more likely to undergo surgical intervention with a significantly prolonged length of stay but had a lower mortality rate.

Mortality During Total Knee Periprosthetic Joint Infection.

BACKGROUND: Periprosthetic joint infections (PJIs) are fraught with multiple complications including poor patient-reported outcomes, disability, reinfection, disarticulation, and even death. We sought to perform a systematic review asking the question: (1) What is the mortality rate of a PJI of the knee undergoing 2-stage revision for infection? (2) Has this rate improved over time? (3) How does this compare to a normal cohort of individuals? METHODS: We performed a database search in MEDLINE/EMBASE, PubMed, and all relevant reference studies using the following keywords: "periprosthetic joint infection," "mortality rates," "total knee arthroplasty," and "outcomes after two stage revision." Two hundred forty-two relevant studies and citations were identified, and 14 studies were extracted and included in the review. RESULTS: A total of 20,719 patients underwent 2-stage revision for total knee PJI. Average age was 66 years. Mean mortality percentage reported was 14.4% (1.7%-34.0%) with average follow-up 3.8 years (0.25-9 years). One-year mortality rate was 4.33% (3.14%-5.51%) after total knee PJI with an increase of 3.13% per year mortality thereafter (r = 0.76 [0.49, 0.90], P < .001). Five-year mortality was 21.64%. When comparing the national age-adjusted mortality (Actuarial Life Table) and the reported 1-year mortality risk in this meta-analysis, the risk of death after total knee PJI is significantly increased, with an odds ratio of 3.05 (95% confidence interval, 2.69-3.44; P < .001). CONCLUSION: The mortality rate after 2-stage total knee revision for infection is very high. When counseling a patient regarding complications of this disease, death should be discussed.

Defining Treatment Success After 2-Stage Exchange Arthroplasty for Periprosthetic Joint Infection.

BACKGROUND: Two-stage exchange arthroplasty remains the preferred surgical treatment method for patients with chronic periprosthetic joint infection (PJI). The success of this procedure is not known exactly as various definitions of success have been used. This study aimed at analyzing the difference in outcome following 2-stage exchange arthroplasty using different definitions for success. METHODS: A retrospective study of 703 patients with PJI who underwent resection arthroplasty and spacer insertion between January 1999 and June 2015 was performed. Chart review identified intraoperative cultures at the time of spacer, reimplantation, and any subsequent reinfections or surgeries following spacer insertion. After applying the exclusion criteria, a total of 570 patients were included in the analysis. Five definitions of treatment success were assessed: (1) Delphi consensus success, (2) modified Delphi consensus success, (3) microbiological success, (4) implant success, and (5) surgical success. RESULTS: Of the 570 patients with PJIs, 458 were reimplanted at a mean of 4.1 months. Mortality was 13.9% with 6.7% occurring before reimplantation. Treatment success was highly variable depending on the definition used (54.2%-88.9%). In 19.6% of PJI cases, the Delphi consensus definition could not be assessed as reimplantation never occurred. Furthermore, 67.0% of these patients underwent reoperations, which may not be accounted for in the Delphi consensus definition. CONCLUSION: Treatment success rates vary dramatically depending on the definition used at our institution. We hope these definitions can help bring forth awareness for standardized reporting of outcomes, but further validation and agreement of these definitions among surgeons and infectious disease physicians is crucial.

Are We Winning or Losing the Battle With Periprosthetic Joint Infection: Trends in Periprosthetic Joint Infection and Mortality Risk for the Medicare Population.

BACKGROUND: Periprosthetic joint infection (PJI) is a potentially deadly complication of total joint arthroplasty. This study was designed to address how the incidence of PJI and outcome of treatment, including mortality, are changing in the population over time. METHODS: Primary total hip arthroplasty (THA) and total knee arthroplasty (TKA) patients with PJI from the 100% Medicare inpatient data set (2005-2015) were identified. Cox proportional hazards regression models for risk of PJI after THA/TKA (accounting for competing risks) or risk of all-cause mortality after PJI were adjusted for patient and clinical factors, with year included as a covariate to test for time trends. RESULTS: The unadjusted 1-year and 5-year risk of PJI was 0.69% and 1.09% for THA and 0.74% and 1.38% for TKA, respectively. After adjustment, PJI risk did not change significantly by year for THA (P = .63) or TKA (P = .96). The unadjusted 1-year and 5-year overall survival after PJI diagnosis was 88.7% and 67.2% for THA and 91.7% and 71.7% for TKA, respectively. After adjustment, the risk of mortality after PJI decreased significantly by year for THA (hazard ratio = 0.97; P < .001) and TKA (hazard ratio = 0.97; P < .001). CONCLUSION: Despite recent clinical focus on preventing PJI, we are unable to detect substantial decline in the risk of PJI over time, although mortality after PJI has declined. Because PJI risk appears not to be changing over time, the incidence of PJI is anticipated to scale up proportionately with the demand for THA and TKA, which is projected to increase substantially in the coming decade.