Incidence and Predictors of Prosthetic Joint Infection Following Primary Total Knee Arthroplasty: A 15-Year Population-Based Cohort Study

Use of intra-operative fluorescence imaging in periprosthetic joint infection: State of the art and future perspectives

BACKGROUND

In periprosthetic joint infections (PJIs), the surgeon's role becomes pivotal in addressing the infection locally, necessitating the surgical removal of infected and necrotic tissue. Opportunity to enhance the visualization of infected tissue during surgery could represent a game-changing innovation.

OBJECTIVE

The aim of this narrative review is to delineate the application of intraoperative fluorescence imaging for targeting infected tissues in PJIs.

METHODS

A systematic review, adhering to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines, was carried out. The search included multiple online database; MEDLINE, Scopus, and Web of Science. For data extraction the following were evaluated: (i) diagnosis of musculoskeletal infection; (ii) use of intraoperative fluorescence imaging; (iii) infected or necrotic tissues as target.

RESULTS

Initially, 116 studies were identified through online database searches and reference investigations. The search was narrowed down to a final list of 5 papers for in-depth analysis at the full-text level. Subsequently, 2 studies were included in the review. The study included a total of 13 patients, focusing on cases of fracture-related infections of the lower limbs.

CONCLUSION

The primary and crucial role for orthopedic surgeons in PJIs is the surgical debridement and precise removal of necrotic and infected tissue. Technologies that enable clear and accurate visualization of the tissue to be removed can enhance the eradication of infections, thereby promoting healing. A promising avenue for the future involves the potential application of intraoperative fluorescence imaging in pursuit of this objective.

Orthopedic Articular and Periarticular Joint Infections

Acute nontraumatic joint pain has an extensive differential. Emergency physicians must be adept at identifying limb and potentially life-threatening infection. Chief among these is septic arthritis. In addition to knowing how these joint infections typically present, clinicians need to be aware of host and pathogen factors that can lead to more insidious presentations and how these factors impact the interpretation of diagnostic tests.

Predictors of Undergoing Revision Within 5 Years of Total Knee Arthroplasty: A Population-Based Study

BACKGROUND

The objective of this study was to identify the rate and risk factors for revision total knee arthroplasty (TKA) within the first 5 years postoperative. Our secondary objective was to identify the rate of additional surgical procedures and death.

METHODS

We conducted a retrospective cohort study among patients in Ontario, Canada who underwent an elective, primary TKA between April 1, 2007, and March 31, 2014, for osteoarthritis. We excluded patients under 40 years and who had undergone a TKA within the previous 15 years. Our final study cohort included 94,193 patients. We reported the proportion of the study cohort who experienced revision surgery within 2 and 5 years of the primary TKA; secondary surgery within 5 years. We conducted Cochran-Armitage tests for trends to assess changes in the proportion of patients who experienced each of the study outcomes, and multivariable logistic regressions to evaluate predictors of a revision TKA.

RESULTS

There were 3,112 (3.3%) patients who had a revision within 5 years, and 1,866 (2.0%) within 2 years of their primary TKA. 3,316 (3.5%) had a secondary surgery (0.6% patellar resurfacing; 1.6% manipulation; 1.3% synovectomy; 0.5% washout; 0.9% debridement). Lower age, men, lower income, higher comorbidity score, depression, previous arthroscopy, lower surgeon volume, and general anesthesia were all significant positive predictors of revision.

CONCLUSIONS

In our study cohort, 2.0% of patients had a revision TKA within 2 years, and 3.3% within 5 years of their primary TKA. Preoperative identification of risk factors may reduce the future prevalence of revision TKAs.

Semaglutide Use Prior to Total Hip Arthroplasty Results in Fewer Postoperative Prosthetic Joint Infections and Readmissions

BACKGROUND

Semaglutide, a novel diabetes management medication, is known for its efficacy in inducing weight loss. Despite this, its impact on outcomes after total hip arthroplasty (THA) remains unclear. The aim of this study was to evaluate if THA patients on semaglutide demonstrate: (1) fewer medical complications; (2) fewer implant-related complications; (3) fewer readmissions; and (4) lower costs.

METHODS

Using a national claims database from 2010 to 2021, we retrospectively examined diabetic patients prescribed semaglutide who underwent primary THA. This yielded 9,465 patients (Semaglutide = 1,653; Control = 7,812). Multivariable logistic regression was used to evaluate the following outcomes: 90-day postoperative medical complications, 2-year implant-related complications, 90-day readmissions, in-hospital lengths of stay, and day-of-surgery and 90-day episode of care costs.

RESULTS

Semaglutide users exhibited lower 90-day readmission rates (6.2 versus 8.8%; odds ratio 0.68; P < .01) and reduced prosthetic joint infections (1.6 versus 2.9%; odds ratio 0.56; P < .01). However, medical complication rates, hospital stays, same-day surgical costs, and 90-day episode costs showed no significant differences.

CONCLUSIONS

This study highlights semaglutide users undergoing THA with fewer 90-day readmissions and 2-year prosthetic joint infections. Although no variance appeared in medical complications, hospital stays, or costs, the medication's notable glycemic control and weight loss benefits could prompt pre-surgery consideration. Further research is essential for a comprehensive understanding of semaglutide's impact on post-THA outcomes.

Comorbid Factors and Selection for Same-Day Total Joint Arthroplasty

Given that the number of total joint arthroplasties (TJAs) performed worldwide is expected to continue to increase, and there are significant costs associated with these procedures, selecting candidates for same-day or 23-hour discharge is important in lowering costs and providing greater access. Younger, healthier patients are excellent candidates for same-day discharge after TJA. Preoperative medical assessment can help exclude patients who may not be candidates, such as patients with 1 or more comorbidities that increase the risk of intra- and postoperative complications and who may require a longer period of monitoring.

Does Computer Navigation or Robotic Assistance Affect the Risk of Periprosthetic Joint Infection in Primary Total Knee Arthroplasty? A Propensity Score-Matched Cohort Analysis

BACKGROUND

The use of technology during total knee arthroplasty (TKA) has been associated with more accurate component position and less blood loss. Yet to date, the risk of developing prosthetic joint infection (PJI) associated with computer navigation (CN) or robotic assistance (RA) has not been thoroughly evaluated. This study used propensity score-matching (PSM) in a large cohort of primary TKA patients to compare the rate of PJI following conventional TKA (TKA) versus CN-TKA and RA-TKA.

METHODS

We retrospectively reviewed 13,015 knees in 11,727 patients who underwent primary TKA at a single institution from 2018 to 2021. The cohort was stratified into TKA, CN-TKA, and RA-TKA groups. 1:1 PSM was applied to 11,834 patients. Propensity score-matching was performed using logistic regression accounting for age, sex, body mass index, Charlson Comorbidity Index (CCI) score, CCI components, and smoking status. Univariate and multivariable analyses were performed to evaluate differences in surgical time and PJI rate.

RESULTS

Significantly longer median operating times were noted in the RA-TKA group (14 minutes) compared to TKA (P < .001). The PJI rates among matched cohorts were similar among RA-TKA (0.3%), CN-TKA (0.3%), and conventional TKA (0.5%). Multivariable logistic regressions demonstrated that the use of robotic assistance (odds ratio (OR) = 0.5, P = .423) or computer navigation (OR = 0.61, P = .128) was not associated with increased risk of PJI when compared to conventional TKA.

CONCLUSIONS

Use of computer navigation and robotic assistance during primary TKA are associated with longer surgical times, but no difference in PJI frequency within 90 days of surgery.

Temporal trends in revision rate due to knee periprosthetic joint infection: a study of 115,120 cases from the Danish Knee Arthroplasty Register

BACKGROUND AND PURPOSE

We aimed to examine the temporal trends in periprosthetic joint infection (PJI) revision incidence after knee arthroplasty (KA) from 1997 through 2019.

PATIENTS AND METHODS

115,120 primary KA cases from the Danish Knee Arthroplasty Register were followed until the first PJI revision. We computed cumulative incidences and adjusted hazard ratios (aHRs) of PJI revision by calendar periods and several patient- and surgical-related risk factors. Results were analyzed from 0-3 months and from 3-12 months after KA.

RESULTS

The overall 1-year PJI revision incidence was 0.7%, increasing from 0.5% to 0.7% (1997 through 2019). The incidence of PJI revision within 3 months increased from 0.1% to 0.5% (1997 through 2019). The adjusted hazard ratio (aHR) within 1 year of primary KA was 5.1 comparing 2017-2019 with 2001-2004. The PJI revision incidence from 3-12 months of KA decreased from 0.4% to 0.2%, with an aHR of 0.5 for 2017-2019 vs. 2001-2004. Male sex, age 75-84 (vs. 65-74), and extreme obesity (vs. normal weight) were positively associated with the risk of PJI revision within 3 months, whereas only male sex was associated from 3-12 months. Partial knee arthroplasty (PKA) vs. total KA was associated with a lower risk of PJI revision both within 3 months and 3-12 months of KA.

CONCLUSION

We observed an increase in PJI revision within 3 months of KA, and a decrease in PJI revision incidence from 3-12 months from 1997 through 2019. The reasons for this observed time-trend are thought to be multifactorial. PKA was associated with a lower risk of PJI revision.

Local adiposity may be a more reliable predictor for infection than body mass index following total knee arthroplasty: a systematic review

PURPOSE

Improved understanding of the factors that predispose TKA patients to infection has considerable economic and medical impact. BMI is commonly used as a proxy for obesity to determine the risk of postoperative infection. However, this metric appears to be fraught with inconsistency in this application. BMI is a simple calculation which provides general insight into body habitus. But it fails to account for anatomic distribution of adipose tissue and the proportion of the mass that is skeletal muscle. Our objective was to review the literature to determine if local adiposity was more predictive than BMI for infection following TKA.

METHODS

A database search was performed for the following PICO (Population, Intervention, Comparison, and Outcome) characteristics: local measurements of adiposity (defined as soft tissue thickness or fat thickness or soft tissue envelope at the knee) in patients over 18 years of age treated with total knee arthroplasty used to determine the relationship between local adiposity and the risk of infection (defined as prosthetic joint infection or wound complication or surgical site infection). Quality was assessed using the GRADE framework and bias was assessed using ROBINS-I .

RESULTS

Six articles (N=7081) met the inclusion criteria. Four of the six articles determined that adiposity was more associated with or was a better predictor for infection risk than BMI. One of the six articles concluded that increased adiposity was protective for short term infection and that BMI was not associated with the outcome of interest. One of the six articles determined that BMI was more strongly associated with PJI risk than soft tissue thickness.

CONCLUSION

The use of adiposity as a proxy for obesity in preoperative evaluation of TKA patients is an emerging concept. Although limited by heterogeneity, the current literature suggests that local adiposity may be a more reliable predictor for infection than BMI following primary TKA.

LEVEL OF EVIDENCE

IV systematic review.

Does Semaglutide Use Decrease Complications and Costs Following Total Knee Arthroplasty?

BACKGROUND

Diabetes mellitus (DM) and obesity are associated with total knee arthroplasty (TKA) complications. Semaglutide, a medication for DM and weight loss, can potentially affect TKA outcomes. This study investigated whether semaglutide use during TKA demonstrates fewer: (1) medical complications; (2) implant-related complications; (3) readmissions; and (4) costs.

METHODS

A retrospective query was performed using a National database to 2021. Patients undergoing TKA for osteoarthritis with DM and semaglutide use were successfully propensity score-matched to controls semaglutide = 7,051; control = 34,524. Outcomes included 90-day postoperative medical complications, 2-year implant-related complications, 90-day readmissions, in-hospital lengths of stay, and costs. Multivariate logistical regressions calculated odds ratios (ORs), 95% confidence intervals, and P values (P < .003 as significance threshold after Bonferroni correction).

RESULTS

Semaglutide cohorts had higher incidence and odds of myocardial infarction (1.0 versus 0.7%; OR 1.49; P = .003), acute kidney injury (4.9 versus 3.9%; OR 1.28; P < .001), pneumonia (2.8 versus 1.7%; OR 1.67; P < .001), and hypoglycemic events (1.9 versus 1.2%; OR 1.55; P < .001), but lower odds of sepsis (0 versus 0.4%; OR 0.23; P < .001). Semaglutide cohorts also had lower odds of prosthetic joint infections (2.1 versus 3.0%; OR 0.70; P < .001) and readmission (7.0 versus 9.4%; OR 0.71; P < .001), and trended toward lower odds of revisions (4.0 versus 4.5%; OR 0.86; P = .02) and 90-day costs ($15,291.66 versus $16,798.46; P = .012).

CONCLUSION

Semaglutide use during TKA decreased risk for sepsis, prosthetic joint infections, and readmissions, but also increased risk for myocardial infarction, acute kidney injury, pneumonia, and hypoglycemic events.

Trends in Revision Knee Arthroplasty for Prosthetic Joint Infection: A Single-Center Study of 384 Knees at a High-Volume Center Between 2008 and 2021

BACKGROUND

Prosthetic joint infection (PJI) is one of the most devastating complications after total knee arthroplasty (TKA), and comorbidities increase the risk. We examined whether a temporal change has occurred in the demographics, especially regarding comorbidities, of patients who have PJI and were treated at our institution over a 13-year study period. In addition, we assessed the surgical methods used and the microbiology of the PJIs.

METHODS

Revisions (n = 384, 377 patients) due to PJI of the knee performed at our institution between 2008 and September 2021 were identified. All included PJIs fulfilled the 2013 International Consensus Meeting diagnostic criteria. The surgeries were categorized into one of the following categories: debridement, antibiotics, and retention (DAIR), 1-stage revision, and 2-stage revision. Infections were classified as early, acute hematogenous, and chronic.

RESULTS

No changes in the median age of the patients nor comorbidity burden were observed during the study period. However, the proportion of 2-stage revisions decreased remarkably from 57.6% in 2008 to 2009 to 6.3% in 2020 to 2021. A DAIR was the most used treatment strategy, but the proportion of 1-stage revisions increased the most. In 2008 to 2009, 12.1% of the revisions were 1-stage, but in 2020 to 2021, the proportion was 43.8%. The most common pathogen was Staphylococcus aureus (27.8%).

CONCLUSION

The comorbidity burden remained at the same level with no trends. A DAIR was the most used strategy, but the proportion of 1-stage revisions rose to almost the same level. The incidence of PJI varied between the years, but remained relatively low.

Periprosthetic Joint Infection: Current Clinical Challenges

Over the last several decades, periprosthetic joint infection has been increasing in incidence and is occurring in more complex patients. While there have been advances in both surgical and medical treatment strategies, there remain important gaps in our understanding. Here, we share our current approaches to the diagnosis and management of periprosthetic joint infection, focusing on frequent clinical challenges and collaborative interdisciplinary care.

Incidence, Microbiological Studies, and Factors Associated With Prosthetic Joint Infection After Total Knee Arthroplasty

Importance

Despite the frequency of total knee arthroplasty (TKA) and clinical implications of prosthetic joint infections (PJIs), knowledge gaps remain concerning the incidence, microbiological study results, and factors associated with these infections.

Objectives

To identify the incidence rates, organisms isolated from microbiological studies, and patient and surgical factors of PJI occurring early, delayed, and late after primary TKA.

Design, Setting, and Participants

This cohort study obtained data from the US Department of Veterans Affairs (VA) Corporate Data Warehouse on patients who underwent elective primary TKA in the VA system between October 1, 1999, and September 30, 2019, and had at least 1 year of care in the VA prior to TKA. Patients who met these criteria were included in the overall cohort, and patients with linked Veterans Affairs Surgical Quality Improvement Program (VASQIP) data composed the VASQIP cohort. Data were analyzed between December 9, 2021, and September 18, 2023.

Exposures

Primary TKA as well as demographic, clinical, and perioperative factors.

Main Outcomes and Measures

Incident hospitalization with early, delayed, or late PJI. Incidence rate (events per 10 000 person-months) was measured in 3 postoperative periods: early (≤3 months), delayed (between >3 and ≤12 months), and late (>12 months). Unadjusted Poisson regression was used to estimate incidence rate ratios (IRRs) with 95% CIs of early and delayed PJI compared with late PJI. The frequency of organisms isolated from synovial or operative tissue culture results of PJIs during each postoperative period was identified. A piecewise exponential parametric survival model was used to estimate IRRs with 95% CIs associated with demographic and clinical factors in each postoperative period.

Results

The 79 367 patients (median (IQR) age of 65 (60-71) years) in the overall cohort who underwent primary TKA included 75 274 males (94.8%). A total of 1599 PJIs (2.0%) were identified. The incidence rate of PJI was higher in the early (26.8 [95% CI, 24.8-29.0] events per 10 000 person-months; IRR, 20.7 [95% CI, 18.5-23.1]) and delayed periods (5.4 [95% CI, 4.9-6.0] events per 10 000 person-months; IRR, 4.2 [95% CI, 3.7-4.8]) vs the late postoperative period (1.3 events per 10 000 person-months). Staphylococcus aureus was the most common organism isolated overall (489 [33.2%]); however, gram-negative infections were isolated in 15.4% (86) of early PJIs. In multivariable analyses, hepatitis C virus infection, peripheral artery disease, and autoimmune inflammatory arthritis were associated with PJI across all postoperative periods. Diabetes, chronic kidney disease, and obesity (body mass index of ≥30) were not associated factors. Other period-specific factors were identified.

Conclusions and Relevance

This cohort study found that incidence rates of PJIs were higher in the early and delayed vs late post-TKA period; there were differences in microbiological cultures and factors associated with each postoperative period. These findings have implications for postoperative antibiotic use, stratification of PJI risk according to postoperative time, and PJI risk factor modification.

Characterizing recurrent infections after one-stage revision for periprosthetic joint infection of the knee: a systematic review of the literature

BACKGROUND

Periprosthetic joint infection (PJI) of the knee represents a severe complication after 1.5% to 2% of primary total knee replacement. Although two-stage revision was considered the gold-standard treatment for PJI of the knee, in the last decades, more studies reported the outcomes of one-stage revisions. This systematic review aims to assess reinfection rate, infection-free survival after reoperation for recurrent infection, and the microorganisms involved in both primary and recurrent infection.

MATERIAL AND METHODS

A systematic review of all studies reporting the outcome of one-stage revision for PJI of the knee up to September 2022, according to PRISMA criteria and AMSTAR2 guidelines, was performed. Patient demographics, clinical, surgical, and postoperative data were recorded.

PROSPERO ID

CRD42022362767.

RESULTS

Eighteen studies with a total of 881 one-stage revisions for PJI of the knee were analyzed. A reinfection rate of 12.2% after an average follow-up of 57.6 months was reported. The most frequent causative microorganism were gram-positive bacteria (71.1%), gram-negative bacteria (7.1%), and polymicrobial infections (8%). The average postoperative knee society score was 81.5, and the average postoperative knee function score was 74.2. The infection-free survival after treatment for recurrent infection was 92.1%. The causative microorganisms at reinfections differed significantly from the primary infection (gram-positive 44.4%, gram-negative 11.1%).

CONCLUSION

Patients who underwent a one-stage revision for PJI of the knee showed a reinfection rate lower or comparable to other surgical treatments as two-stage or DAIR (debridement, antibiotics, and implant retention). Reoperation for reinfection demonstrates a lower success compared to one-stage revision. Moreover, microbiology differs between primary infection and recurrent infection. Level of evidence Level IV.

Killing of a Multispecies Biofilm Using Gram-Negative and Gram-Positive Targeted Antibiotic Released from High Purity Calcium Sulfate Beads

BACKGROUND

Multispecies biofilm orthopedic infections are more challenging to treat than mono-species infections. In this in-vitro study, we aimed to determine if a multispecies biofilm, consisting of Gram positive and negative species with different antibiotic susceptibilities could be treated more effectively using high purity antibiotic-loaded calcium sulfate beads (HP-ALCSB) containing vancomycin (VAN) and tobramycin (TOB) in combination than alone.

METHODS

Three sets of species pairs from bioluminescent strains of Pseudomonas aeruginosa (PA) and Staphylococcus aureus (SA) and clinical isolates, Enterococcus faecalis (EF) and Enterobacter cloacae were screened for compatibility. PA + EF developed intermixed biofilms with similar cell concentrations and so were grown on 316L stainless steel coupons for 72 h or as 24 h agar lawn biofilms and then treated with HP-ALCSBs with single or combination antibiotics and assessed by viable count or bioluminescence and light imaging to distinguish each species. Replica plating was used to assess viability.

RESULTS

The VAN + TOB bead significantly reduced the PA + EF biofilm CFU and reduced the concentration of surviving antibiotic tolerant variants by 50% compared to single antibiotics.

CONCLUSIONS

The combination of Gram-negative and positive targeted antibiotics released from HP-ALCSBs may be more effective in treating multispecies biofilms than monotherapy alone.

Annual incidence and assessment of risk factors for early-onset deep surgical site infection following primary total knee arthroplasty in osteoarthritis

Aims

This study aims to determine difference in annual rate of early-onset (≤ 90 days) deep surgical site infection (SSI) following primary total knee arthroplasty (TKA) for osteoarthritis, and to identify risk factors that may be associated with infection.

Methods

This is a retrospective population-based cohort study using prospectively collected patient-level data between 1 January 2013 and 1 March 2020. The diagnosis of deep SSI was defined as per the Centers for Disease Control/National Healthcare Safety Network criteria. The Mann-Kendall Trend test was used to detect monotonic trends in annual rates of early-onset deep SSI over time. Multiple logistic regression was used to analyze the effect of different patient, surgical, and healthcare setting factors on the risk of developing a deep SSI within 90 days from surgery for patients with complete data. We also report 90-day mortality.

Results

A total of 39,038 patients underwent primary TKA for osteoarthritis during the study period. Of these, 275 patients developed a deep SSI within 90 days of surgery, representing a cumulative incidence of 0.7%. The annual infection rate did not significantly decrease over the seven-year study period (p = 0.162). Overall, 13,885 (35.5%) cases were excluded from the risk analysis due to missing data. Risk factors associated with early-onset deep SSI included male sex, American Society of Anesthesiologists grade ≥ 3, blood transfusion, acute length of stay, and surgeon volume < 30 TKAs/year. Early-onset deep SSI was not associated with increased 90-day mortality.

Conclusion

This study establishes a reliable baseline infection rate for early-onset deep SSI after TKA for osteoarthritis using robust Infection Prevention and Control surveillance data, and identifies several potentially modifiable risk factors.

The use of antibiotic-loaded bone cement and systemic antibiotic prophylactic use in 2,971,357 primary total knee arthroplasties from 2010 to 2020: an international register-based observational study among countries in Africa, Europe, North America, and Oceania

BACKGROUND AND PURPOSE

Antibiotic-loaded bone cement (ALBC) and systemic antibiotic prophylaxis (SAP) have been used to reduce periprosthetic joint infection (PJI) rates. We investigated the use of ALBC and SAP in primary total knee arthroplasty (TKA).

PATIENTS AND METHODS

This observational study is based on 2,971,357 primary TKAs reported in 2010-2020 to national/regional joint arthroplasty registries in Australia, Denmark, Finland, Germany, Italy, the Netherlands, New Zealand, Norway, Romania, South Africa, Sweden, Switzerland, the UK, and the USA. Aggregate-level data on trends and types of bone cement, antibiotic agents, and doses and duration of SAP used was extracted from participating registries.

RESULTS

ALBC was used in 77% of the TKAs with variation ranging from 100% in Norway to 31% in the USA. Palacos R+G was the most common (62%) ALBC type used. The primary antibiotic used in ALBC was gentamicin (94%). Use of ALBC in combination with SAP was common practice (77%). Cefazolin was the most common (32%) SAP agent. The doses and duration of SAP used varied from one single preoperative dosage as standard practice in Bolzano, Italy (98%) to 1-day 4 doses in Norway (83% of the 40,709 TKAs reported to the Norwegian arthroplasty register).

CONCLUSION

The proportion of ALBC usage in primary TKA varies internationally, with gentamicin being the most common antibiotic. ALBC in combination with SAP was common practice, with cefazolin the most common SAP agent. The type of ALBC and type, dose, and duration of SAP varied among participating countries.

A systematic review and meta-analysis comparing outcomes following total knee arthroplasty for rheumatoid arthritis versus for osteoarthritis

PURPOSE

Total knee arthroplasty (TKA) in patients with osteoarthritis (OA) are considered to be a successful procedure, but with little being known about outcomes in patients with rheumatoid arthritis (RA). The aim of this study was to compare the outcomes of TKA in patients with RA versus OA.

METHODS

Data were obtained from PubMed, Cochrane Library, EBSCO and Scopus for all available studies comparing the outcomes of THA in RA and OA patients (From January 1, 2000 to October 15, 2022). Outcomes of interest included infection, revision, venous thromboembolism (VTE), mortality, periprosthetic fractures, prosthetic loosening, length of stay, and satisfaction. Two reviewers independently assessed each study for quality and extracted data. The quality of the studies was scored using the Newcastle-Ottawa scale (NOS).

RESULTS

Twenty-four articles with a total 8,033,554 patients were included in this review. The results found strong evidence for increased risk of overall infection (OR = 1.61, 95% CI, 1.24-2.07; P = 0.0003), deep infection (OR = 2.06, 95% CI, 1.37-3.09; P = 0.0005), VTE (OR = 0.76, 95% CI, 0.61-0.93; P = 0.008), pulmonary embolism (PE) (OR = 0.84, 95% CI, 0.78-0.90; P<0.00001), periprosthetic fractures (OR = 1.87, 95% CI, 1.60-2.17; P<0.00001); and reasonable evidence for increased risk of deep venous thrombosis (DVT) (OR = 0.74, 95% CI, 0.54-0.99; P = 0.05), and length of stay (OR = 0.07, 95% CI, 0.01-0.14; P = 0.03) after TKA in patients with RA versus OA. There were no significant differences in superficial site infection (OR = 0.84,95% CI, 0.47-1.52; P = 0.57), revision (OR = 1.33,95% CI, 0.79-2.23; P = 0.28), mortality (OR = 1.16,95% CI, 0.87-1.55; P = 0.32), and prosthetic loosening (OR = 1.75, 95% CI, 0.56-5.48; P = 0.34) between the groups.

CONCLUSION

Our study demonstrated that patients with RA have a higher risk of postoperative infection, VTE, periprosthetic fracture, and lengths of stay, but did not increase revision rate, prosthetic loosening and mortality compared to patients with OA following TKA. In conclusion, despite RA increased incidence of postoperative complications, TKA should continue to be presented as an effective surgical procedure for patients whose conditions are intractable to conservative and medical management of RA.

What is the Safe Distance Between Hip and Knee Implants to Reduce the Risk of Ipsilateral Metachronous Periprosthetic Joint Infection?

BACKGROUND

Periprosthetic joint infection (PJI), the most common cause of revision after TKA and THA, is a devastating complication for patients that is difficult to diagnose and treat. An increase in the number of patients with multiple joint arthroplasties in the same extremity will result in an increased risk of ipsilateral PJI. However, there is no definition of risk factors, micro-organism patterns, and safe distance between knee and hip implants for this patient group.

QUESTIONS/PURPOSES

(1) In patients with hip and knee arthroplasties on the same side who experience a PJI of one implant, are there factors associated with the development of subsequent PJI of the other implant? (2) In this patient group, how often is the same organism responsible for both PJIs? (3) Is a shorter distance from an infected prosthetic joint to an ipsilateral prosthetic joint associated with greater odds of subsequent infection of the second joint?

METHODS

We designed a retrospective study of a longitudinally maintained institutional database that identified all one-stage and two-stage procedures performed for chronic PJI of the hip and knee at our tertiary referral arthroplasty center between January 2010 and December 2018 (n = 2352). Of these patients, 6.8% (161 of 2352) had an ipsilateral hip or knee implant in situ at the time of receiving surgical treatment for a PJI of the hip or knee. The following criteria led to the exclusion of 39% (63 of 161) of these patients: 4.3% (seven of 161) for incomplete documentation, 30% (48 of 161) for unavailability of full-leg radiographs, and 5% (eight of 161) for synchronous infection. With regard to the latter, per internal protocol, all artificial joints were aspirated before septic surgery, allowing us to differentiate between synchronous and metachronous infection. The remaining 98 patients were included in the final analysis. Twenty patients experienced ipsilateral metachronous PJI during the study period (Group 1) and 78 patients did not experience a same-side PJI (Group 2). We analyzed the microbiological characteristics of bacteria during the first PJI and ipsilateral metachronous PJI. Calibrated, full-length plain radiographs were evaluated. Receiver operating characteristic curves were analyzed to determine the optimal cutoff for the stem-to-stem and empty native bone distance. The mean time between the initial PJI and ipsilateral metachronous PJI was 8 ± 14 months. Patients were followed for a minimum of 24 months for any complications.

RESULTS

The risk of ipsilateral metachronous PJI in the other joint secondary to a joint implant in which PJI develops can increase up to 20% in the first 2 years after the procedure. There was no difference between the two groups in age, sex, initial joint replacement (knee or hip), and BMI. However, patients in the ipsilateral metachronous PJI group were shorter and had a lower weight (1.6 ± 0.1 m and 76 ± 16 kg). An analysis of the microbiological characteristics of bacteria at the time of the initial PJI showed no differences in the proportions of difficult-to-treat, high virulence, and polymicrobial infections between the two groups (20% [20 of 98] versus 80% [78 of 98]). Our findings showed that the ipsilateral metachronous PJI group had a shorter stem-to-stem distance, shorter empty native bone distance, and a higher risk of cement restrictor failure (p < 0.01) than the 78 patients who did not experience ipsilateral metachronous PJI during the study period. An analysis of the receiver operating characteristic curve showed a cutoff of 7 cm for the empty native bone distance (p < 0.01), with a sensitivity of 72% and a specificity of 75%.

CONCLUSION

The risk of ipsilateral metachronous PJI in patients with multiple joint arthroplasties is associated with shorter stature and stem-to-stem distance. Appropriate position of the cement restrictor and native bone distance are important in reducing the risk of ipsilateral metachronous PJI in these patients. Future studies might evaluate the risk of ipsilateral metachronous PJI owing to bone adjacency.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Prevention Techniques Have Had Minimal Impact on the Population Rate of Prosthetic Joint Infection for Primary Total Hip and Knee Arthroplasty: A National Database Study

BACKGROUND

Several studies over the years have offered modalities that may greatly decrease the rate of periprosthetic joint infection when implemented. As a result, one would expect a drastic decrease in infection rate among the implementing population with its widespread use. The purpose of this study was to assess whether there exists a decrease in infection rate over time, after accounting for available confounding variables, within a large national database.

METHODS

A large national database from 2005 to 2019 was queried for primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). In total, 221,416 THAs and 354,049 TKAs were performed over the study period. Differences in 30-day infection rate were assessed with time and available preoperative risk factors using multinominal logistic regressions.

RESULTS

Rate of infection overall trended downward for both THA and TKA. After accounting for confounding variables, odds of THA infection marginally decreased over time (odds ratio 0.968 [0.952-0.985], P < .0001), while the odds of a TKA infection marginally increased with time (odds ratio 1.037 [1.020-1.054], P < .0001).

CONCLUSION

Individual peer-reviewed publications have presented infection control modalities demonstrating dramatic decreases in infection rate while analysis at a population level shows almost no changes in infection rate over a 15-year time period. This study supports continued investigation for influential modalities in preventing periprosthetic joint infection and care in patient selection for primary hip and knee arthroplasty.

Outcomes of artificial urinary sphincter implantation in patients with diabetes mellitus: A subgroup analysis

OBJECTIVES

To estimate the surgical and quality-of-life outcomes of artificial urinary sphincter implantation in patients with diabetes mellitus (DM). Subanalyses were performed using the same population as that in our previous multicenter, prospective, observational study.

METHODS

A total of 135 male patients who underwent primary artificial urinary sphincter implantation were divided into two groups: those with and without DM. The revision-free rates, that is, the percentage of patients who did not require revision surgery, were compared between patients with and without DM. The number of urinary pads required per day, International Consultation on Incontinence Questionnaire-Short Form, and King's Health Questionnaire were used to compare the continence status and quality of life (QOL) between the two groups preoperatively and at 1, 3, and 12 months after surgery.

RESULTS

Revision-free rates were significantly lower in the DM group (83.9%, 77.4%, and 67.8% at 1, 2, and 3 years after implantation, respectively) than in the non-DM group (95.5%, 92.5%, and 85.5% at 1, 2, and 3 years after implantation, respectively). Both continence status and QOL, assessed by questionnaires, markedly improved after surgery in patients with and without DM.

CONCLUSIONS

Despite differences in the durability of the artificial urinary sphincters, patients with DM can obtain as much benefit from artificial urinary sphincter implantation regarding continence and quality-of-life improvement as patients without DM. Therefore, DM was not considered a comorbidity that contraindicated artificial urinary sphincter implantation. Additional large-scale studies are required to verify our findings.

A Comparison of Outcomes of Culture positive and Culture negative Acute Knee Prosthetic Joint Infection following Debridement, Antibiotics and Implant Retention (DAIR)

PURPOSE

We aim to compare the outcome of culture-positive (CP PJI) and culture-negative (CN PJI) acute knee prosthetic joint infection (PJI) following debridement, antibiotics and implant retention (DAIR) with polyethylene insert exchange. We also aim to analyze the factors associated with the successful outcome of DAIR and the influence of failed DAIR on the outcome of subsequent two-stage revision arthroplasty.

METHODS

We performed a retrospective review of 36 consecutive patients who underwent DAIR for acute PJI between January 2013 and January 2018. The patient's demographic data, McPherson grade, surgical details, laboratory and microbiology data were retrieved from the medical records. All the patients have been followed up for a minimum of 3 years or until re-operation, revision or death and any complications, incidence of DAIR failure, revision and mortality were noted.

RESULTS

The mean follow-up was 4.9 ± 2.4 years. Among the 36 patients, 16 had CP PJI and 20 had CN PJI. Among the 16 patients with CP PJI, 8 patients had success with DAIR and 8 patients had a recurrence of infection (50%) at a mean of 21 months (range, 2 weeks to 55 months). Among the 20 patients with CN PJI, 14 patients had success with DAIR and 6 patients had a recurrence of infection [30% (6/20)] at a mean of 69 months (range, 13-221 months) (p < .05). The Kaplan-Meir survival analysis showed survivorship did not vary significantly between both groups (p > .05). Univariate regression analysis showed symptom duration of more than one month found to be significantly associated with the DAIR failure. There was no difference in failure rate after DAIR between age, Charlson comorbidity index, early postoperative versus acute hematogenous group and type of organism grown. Ten out of 14 DAIR failures were successfully managed with two-stage revision surgery with no recurrence of infection till the final follow-up. In the remaining 4 patients, one underwent re-debridement, two underwent arthrodesis and one was left with an antibiotic cement spacer.

CONCLUSION

DAIR with polyethylene exchange will give comparable results irrespective of the culture positivity. Symptom duration of more than 30 days for DAIR is significantly associated with DAIR failure. DAIR failures can be successfully managed with two-stage revision.

Risk Factors for Periprosthetic Joint Infection after Primary Total Knee Arthroplasty

Periprosthetic joint infection (PJI) is a major adverse event of primary total knee arthroplasty (TKA) from the patient's perspective, and it is also costly for health care systems. In 2010, the reported incidence of PJI in the first 2 years after TKA was 1.55%, with an incidence of 0.46% between the second and tenth year. In 2022, it has been published that 1.41% of individuals require revision TKA for PJI. The following risk factors have been related to an increased risk of PJI: male sex, younger age, type II diabetes, obesity class II, hypertension, hypoalbuminemia, preoperative nutritional status as indicated by prognostic nutritional index (PNI) and body mass index, rheumatoid arthritis, post-traumatic osteoarthritis, intra-articular injections prior to TKA, previous multi-ligament knee surgery, previous steroid therapy, current tobacco use, procedure type (bilateral), length of stay over 35 days, patellar resurfacing, prolonged operative time, use of blood transfusions, higher glucose variability in the postoperative phase, and discharge to convalescent care. Other reported independent risk factors for PJI (in diminishing order of importance) are congestive heart failure, chronic pulmonary illness, preoperative anemia, depression, renal illness, pulmonary circulation disorders, psychoses, metastatic tumor, peripheral vascular illness, and valvular illness. Preoperative intravenous tranexamic acid has been reported to diminish the risk of delayed PJI. Knowing the risk factors for PJI after TKA, especially those that are avoidable or controllable, is critical to minimizing (ideally preventing) this complication. These risk factors are outlined in this article.

Patients at a high risk of PJI: Can we reduce the incidence of infection using dual antibiotic-loaded bone cement?

Prosthetic joint infection (PJI) is one of the most devastating complications of orthopedic surgery. However, not all patients are equally at the risk of severe infection. The incidences of PJI vary with the host and surgery-related risk factors. It is now generally accepted that some important medical comorbidities may predispose the patients to a high risk of PJI. Time-consuming and invasive surgical procedures, such as revision arthroplasties, are also associated with a high incidence of PJI, presumably due to the increased risk of surgical site contamination. Effective infection-preventing strategies should begin with identifying and optimizing the patients at a high risk of infection prior to surgery. Optimizing the operating room environment and antibiotic prophylaxis are also essential strategies that help minimize the overall incidence of infection in orthopedic surgery. The ideal antibiotic prophylaxis is still under debate, and discussions have emerged about whether variations or adjustments to the standard protocol are justified in patients at a high risk of infection. This also includes evaluating the possible benefits and risks of using high-dose dual antibiotic-loaded bone cement instead of low-dose single antibiotic-loaded bone cement in arthroplasty. This review summarizes the evidence showing that the combination of two local antibiotics in bone cement exerts a strong and longer-lasting antimicrobial effect against PJI-associated pathogens. This conclusion is consistent with the preliminary clinical studies showing a low incidence of PJI in high-risk patients undergoing cemented hemiarthroplasty, cemented revision, and primary arthroplasty if dual ALBC is used. These results may encourage clinicians to consolidate this hypothesis in a wider clinical range.

Registries: Big data, bigger problems?

Patient registries have grown in size and number along with general computing power and digitization of the healthcare world. In contrast to databases, registries are typically patient data systematically created and collected for the express purpose of answering health-related questions. Registries can be disease-, procedure-, pathology-, or product-based in nature. Registry-based studies typically fit into Level II or III in the hierarchy of evidence-based medicine. However, a recent advent in the use of registry data has been the development and execution of registry-based trials, such as the TASTE trial, which may elevate registry-based studies into the realm of Level I evidence. Some strengths of registries include the sheer volume of data, the inclusion of a diverse set of participants, and their ability to be linked to other registries and databases. Limitations of registries include variable quality of the collected data, and a lack of active follow-up (which may underestimate rates of adverse events). As with any study type, the intended design does not automatically lead to a study of a certain quality. While no specific tool exists for assessing the quality of a registry-based study, some important considerations include ensuring the registry is appropriate for the question being asked, whether the patient population is representative, the presence of an appropriate comparison group, and the validity and generalizability of the registry in question. The future of clinical registries remains to be seen, but the incorporation of big data and machine learning algorithms will certainly play an important role.