Predictive model for surgical site infection risk after surgery for high-energy lower-extremity fractures: development of the risk of infection in orthopedic trauma surgery score

Risk factors for infection in severe open tibial shaft fractures

OBJECTIVE

To evaluate risk factors for infection in severe open tibial shaft fractures.

METHODS

A secondary analysis of a multicenter prospective study investigated internal versus external fixation of severe open tibia fractures at 20 US Level I trauma centers. Adult patients, aged <65 years, with a Gustilo-Anderson Type IIIB or severe IIIA metaphyseal or diaphyseal tibia fracture were included. All fractures underwent definitive fixation with either a modern ring external fixator, intramedullary device, and/or plate. Fourteen variables previously identified as risk factors for infection were included in the analysis. Deep surgical site infection was defined as an infection treated with surgical debridement within 1 year of index surgery.

RESULTS

The study cohort included 430 patients. Deep surgical site infection requiring reoperation occurred in 108 (25 %) patients. The final model identified four risk factors for infection: age >40 years (OR, 2.00; 95 % CI, 1.3-3.1), Gustilo-Anderson Type IIIB (OR, 1.80; 95 % CI, 1.1-3.0), embedded wound contamination (OR, 1.69; 95 % CI, 1.1-2.7), and wound length (OR, 1.02/cm; 95 % CI, 1.0-1.05). The model performed poorly at distinguishing infected from uninfected patients (Area Under the Curve=0.57; 95 % CI, 0.51-0.63).

CONCLUSIONS

Surgeons can now counsel patients with these risk factors that they are at a markedly higher risk of infection. The identification of these risk factors may direct future research aimed at mitigating the risk of deep surgical site infection in this patient population.

Timing of Fracture Fixation in Ankle Fracture-Dislocations

Ankle fracture-dislocations may require delayed internal fixation. Our aim was to compare acute open reduction and internal fixation (ORIF) with delayed ORIF, using external fixation or cast splint in ankle fracture-dislocations. Factors that affect the rates of re-operation and Surgical site infection (SSI) were identified. In this retrospective cohort study, patients were included with open and closed ankle fracture-dislocations treated with ORIF from two large peripheral hospitals and one academic center in the Netherlands. This study included 447 patients with an ankle fracture-dislocation. In the multivariate analysis, the difference between surgery <48 hours compared to bridging with cast or external fixation had no significant influence on unscheduled re-operation or SSI. Higher body mass index (BMI) and open fractures had a significant positive correlation with re-operation while diabetes mellitus (DM) and open fractures correlated with SSI. In patients with open fractures, there was also no significant difference in outcome between acute or delayed internal fixation. We suggest that it is safe to perform primary ORIF on all dislocated ankle fractures if the soft tissue injury allows surgery within 48 hours. When significant swelling is present, patients with well-reduced fractures and with no soft tissue injury could be treated safely with a cast until delayed ORIF is possible.Level of Evidence: Therapeutic level 2B (retrospective cohort study).

External Validation of a Predictive Score for Fracture-Related Infections in Orthopedic Trauma Surgery

BACKGROUND

The purpose of this study was to externally validate a predictive score for fracture-related infections, establishing generalizability for absolute and relative risk of infection in the setting of orthopedic fracture surgery.

MATERIALS AND METHODS

This was a retrospective, case-control study performed at a level I academic trauma center that included 147 patients with fracture-related infection in the study group and 300 control patients. We analyzed the same 8 independent predictors of fracture-related infection cited by a previous study. We then used the area under the receiver operating characteristics curve (AUC) to compare the derivation and validation cohorts. The validation and derivation cohorts were then compared by grouping patients into 4 strata of Wise score groups. This allowed for comparison of AUC and risk of fracture-related infection in our institution with those in the previously studied institution.

RESULTS

The resulting data yielded an AUC (0.74) nearly identical to that of the previously studied institution. It was also found that the relative risk of infection correlated with the Wise score in the same way the initial model did with the absolute risks being similar.

CONCLUSION

The previous predictive model was externally validated and shown to be generalizable to a different patient population. The relative risk of a fracture-related infection can be determined using this scoring model preoperatively with the goal of aiding in patient counseling and surgical decision-making, giving a quantitative value to patient risk factors. [Orthopedics. 2024;47(5):e268-e272.].

-A machine learning model to predict surgical site infection after surgery of lower extremity fractures

PURPOSE

This study aimed to develop machine learning algorithms for identifying predictive factors associated with the risk of postoperative surgical site infection in patients with lower extremity fractures.

METHODS

A machine learning analysis was conducted on a dataset comprising 1,579 patients who underwent surgical fixation for lower extremity fractures to create a predictive model for risk stratification of postoperative surgical site infection. We evaluated different clinical and demographic variables to train four machine learning models (neural networks, boosted generalised linear model, naïve bayes, and penalised discriminant analysis). Performance was measured by the area under the curve score, Youdon's index and Brier score. A multivariate adaptive regression splines (MARS) was used to optimise predictor selection.

RESULTS

The final model consisted of five predictors. (1) Operating room time, (2) ankle region, (3) open injury, (4) body mass index, and (5) age. The best-performing machine learning algorithm demonstrated a promising predictive performance, with an area under the ROC curve, Youdon's index, and Brier score of 77.8%, 62.5%, and 5.1%-5.6%, respectively.

CONCLUSION

The proposed predictive model not only assists surgeons in determining high-risk factors for surgical site infections but also empowers patients to closely monitor these factors and take proactive measures to prevent complications. Furthermore, by considering the identified predictors, this model can serve as a reference for implementing preventive measures and reducing postoperative complications, ultimately enhancing patient outcomes. However, further investigations involving larger datasets and external validations are required to confirm the reliability and applicability of our model.

Predictive factors for infection after osteosynthesis of tibial plateau fractures: a retrospective study of 314 patients

INTRODUCTION

The reported incidence of infection related with tibial plateau fractures (IRTPF) ranges from 2 to 23%. This complication can result in catastrophic consequences such as deformity, post-traumatic osteoarthritis, chronic pain, loss of function, and substantial economic burdens on healthcare systems due to extended hospital stays and the resources required for treatment. Consequently, it is imperative to emphasize the identification of infection risk factors.

METHODS

A retrospective case-control study was designed, encompassing patients who underwent surgery for tibial plateau fractures between 2015 and 2020. Frequencies and measures of central tendency were compared between infected patients (cases) and non-infected patients (controls) using rank-based statistical tests. Subsequently, two logistic regression models were employed to control for potential confounding variables.

RESULTS

A total of 314 patients were included, predominantly male (71.15%). Average age of 44.41 years. IRTPF were observed in 7.64% of the patients. In the univariate inferential statistical analysis, high-energy fractures (OR 6.35, p < 0.001), fractures with compartment syndrome (OR 7.10, p < 0.001), two-stage management with temporary external fixation (OR 8.18, p < 0.001), the use of 2 or more approaches in definitive surgery (OR 2.93, p = 0.011), and the use of two or more plates (OR 9.17, p < 0.001) were identified as risk factors for infection. On average, the duration of surgery in infected patients was 201.2 min, compared to 148.4 min in non-infected patients (p < 0.001). When performing two logistic regression models, the following independent risk factors were identified: high-energy fractures (OR 5.04, p = 0.012), the presence of compartment syndrome (OR 4.53, p = 0.007), and the use of two or more plates in definitive surgery (OR 5.04, p = 0.023).

CONCLUSIONS

High-energy tibial plateau fractures (Schatzker IV, V, and VI), the presence of concomitant compartment syndrome, and the use of 2 or more plates in definitive surgery are associated with a higher risk of infection related to fracture following open reduction and osteosynthesis treatment.

LEVEL OF EVIDENCE

Case-Control Study.

LEVEL III EVIDENCE

Risk factors for surgical site infections following open reduction and internal fixation in patients with tibial plateau fractures

This retrospective cohort study aimed to identify the risk factors associated with postoperative wound infections in patients undergoing open reduction and internal fixation for tibial plateau fractures. The study was conducted between January 2019 and December 2022, with stringent inclusion and exclusion criteria. Data were collected from the Electronic Health Record system, including demographic information, lifestyle habits, comorbid conditions and surgical variables like preoperative American Society of Anesthesiologists (ASA) scores. The IBM Statistical Package for the Social Sciences, version 27.0, was utilized for rigorous statistical analyses. Univariate analysis identified several factors, such as body mass index (BMI), smoking status and diabetes mellitus, as significant predictors of postoperative wound infection. Multivariate logistic regression revealed that BMI, type of fracture (open vs. closed), surgery duration exceeding 150 min, preoperative albumin levels below 35 g/L and preoperative ASA score of 3 or higher were significant independent risk factors (p < 0.05). Patients with open fractures, preoperative malnutrition, elevated preoperative ASA scores and a history of smoking are at a heightened risk of developing postoperative wound infections. Timely preoperative evaluation of these risk factors is crucial for minimizing the risk of surgical site infections and optimizing clinical management.

Case Report: Hip arthroplasty after fracture-related joint infection caused by extensively drug-resistant Klebsiella pneumoniae

This case-report focuses on a 23-year-old soldier suffering from a fracture-related hip joint infection (FRI) due to extensively drug-resistant Klebsiella pneumoniae and S. epidermidis. The patient underwent multiple septic revision surgeries including the removal of remaining shrapnel accompanied by last-resort antimicrobial therapy with cefiderocol and colistin. Additionally, the surgeries included repeated tissue sampling for microbiological and histopathological analysis. An antibiotic-loaded cemented filler containing cefiderocol was used to improve local antimicrobial therapy. The biopsies prior to and during hip replacement surgery confirmed successful microbe eradication. Hip arthroplasty restored hip joint function and significantly improved patient's quality of life. The utilization of a trabecular metal shell and a meta-diaphyseally anchored cementless hip stem ensured secure implant fixation and early patient mobilisation. An adjusted biofilm active oral antimicrobial therapy after arthroplasty intervention was continued to prevent early periprosthetic joint infection. This case emphasizes the difficulties of managing FRI and multidrug-resistant pathogens. It contributes valuable insight into navigating complex orthopedic cases while ensuring successful hip arthroplasty outcomes. In conclusion, early interdisciplinary collaboration, appropriate antimicrobial therapy along with tailored surgical interventions are crucial for managing such complex cases successfully.

A predictive nomogram for surgical site infection in patients who received clean orthopedic surgery: a retrospective study

BACKGROUND

Surgical site infection (SSI) is a common and serious complication of elective clean orthopedic surgery that can lead to severe adverse outcomes. However, the prognostic efficacy of the current staging systems remains uncertain for patients undergoing elective aseptic orthopedic procedures. This study aimed to identify high-risk factors independently associated with SSI and develop a nomogram prediction model to accurately predict the occurrence of SSI.

METHODS

A total of 20,960 patients underwent elective clean orthopedic surgery in our hospital between January 2020 and December 2021, of whom 39 developed SSI; we selected all 39 patients with a postoperative diagnosis of SSI and 305 patients who did not develop postoperative SSI for the final analysis. The patients were randomly divided into training and validation cohorts in a 7:3 ratio. Univariate and multivariate logistic regression analyses were conducted in the training cohort to screen for independent risk factors of SSI, and a nomogram prediction model was developed. The predictive performance of the nomogram was compared with that of the National Nosocomial Infections Surveillance (NNIS) system. Decision curve analysis (DCA) was used to assess the clinical decision-making value of the nomogram.

RESULTS

The SSI incidence was 0.186%. Univariate and multivariate logistic regression analysis identified the American Society of Anesthesiology (ASA) class (odds ratio [OR] 1.564 [95% confidence interval (CI) 1.029-5.99, P = 0.046]), operative time (OR 1.003 [95% CI 1.006-1.019, P < 0.001]), and D-dimer level (OR 1.055 [95% CI 1.022-1.29, P = 0.046]) as risk factors for postoperative SSI. We constructed a nomogram prediction model based on these independent risk factors. In the training and validation cohorts, our predictive model had concordance indices (C-indices) of 0.777 (95% CI 0.672-0.882) and 0.732 (95% CI 0.603-0.861), respectively, both of which were superior to the C-indices of the NNIS system (0.668 and 0.543, respectively). Calibration curves and DCA confirmed that our nomogram model had good consistency and clinical predictive value, respectively.

CONCLUSIONS

Operative time, ASA class, and D-dimer levels are important clinical predictive indicators of postoperative SSI in patients undergoing elective clean orthopedic surgery. The nomogram predictive model based on the three clinical features demonstrated strong predictive performance, calibration capabilities, and clinical decision-making abilities for SSI.

Predicting Which Species of Bacteria Will Cause an Infection After Fracture Surgery

The aim of this study was to develop and validate risk prediction models for deep surgical site infection (SSI) caused by specific bacterial pathogens after fracture fixation. A retrospective case-control study was conducted at a level I trauma center. Fifteen candidate predictors of the bacterial pathogens in deep SSI were evaluated to develop models of bacterial risk. The study included 441 patients with orthopedic trauma with deep SSI after fracture fixation and 576 control patients. The main outcome measurement was deep SSI cultures positive for methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant S aureus (MRSA), gram-negative rods (GNRs), anaerobes, or polymicrobial infection within 1 year of injury. Prognostic models were developed for five bacterial pathogen outcomes. Mean area under the curve ranged from 0.70 (GNRs) to 0.74 (polymicrobial). Strong predictors of MRSA were American Society of Anesthesiologists (ASA) classification of III or greater (odds ratio [OR], 3.4; 95% CI, 1.6-8.0) and time to fixation greater than 7 days (OR, 3.4; 95% CI, 1.9-5.9). Gustilo type III fracture was the strongest predictor of MSSA (OR, 2.5; 95% CI, 1.6-3.9) and GNRs (OR, 3.4; 95% CI, 2.3-5.0). ASA classification of III or greater was the strongest predictor of polymicrobial infection (OR, 5.9; 95% CI, 2.7-15.5) and was associated with increased odds of GNRs (OR, 2.7; 95% CI, 1.5-5.5). Our models predict the risk of MRSA, MSSA, GNR, anaerobe, and polymicrobial infections in patients with fractures. The models might allow for modification of preoperative antibiotic selection based on the particular pathogen posing greatest risk for this patient population. [Orthopedics. 2024;47(1):e19-e25.].

Rate and factors associated with surgical site infection following aseptic revision fixation of orthopaedic trauma injuries

PURPOSE

The primary aim of this study was to define the rate of infection following revision of fixation for aseptic failure. The secondary aims were to identify factors associated with an infection following revision and patient morbidity following deep infection.

METHODS

A retrospective study was undertaken to identify patients who underwent aseptic revision surgery during a 3-year period (2017-2019). Regression analysis was used to identify independent factors associated with SSI.

RESULTS

Eighty-six patients were identified that met the inclusion criteria, with a mean age of 53 (range 14-95) years and 48 (55.8%) were female. There were 15 (17%) patients with an SSI post revision surgery (n = 15/86). Ten percent (n = 9) of all revisions acquired a 'deep infection', which carried a high morbidity with a total of 23 operations, including initial revision, being undertaken for these patients as salvage procedures and three progressed to an amputation. Alcohol excess (odds ratio (OR) 1.61, 95% CI 1.01-6.36, p = 0.046) and chronic obstructive pulmonary disease (OR 11.1, 95% CI 1.00-133.3, p = 0.050) were independently associated with an increased risk of SSI.

CONCLUSION

Aseptic revision surgery had a high rate of SSI (17%) and deep infection (10%). All deep infections occurred in the lower limb with the majority of these seen in ankle fractures. Alcohol excess and COPD were independent risk factors associated with an SSI and patients with a history of these should be counselled accordingly.

LEVEL OF EVIDENCE

Retrospective Case Series, Level IV.

Comparative Analysis of Eccentric Glenosphere in Reverse Total Shoulder Arthroplasty: A Computer Simulation Study

Objective

The aim was to evaluate the effects of different glenosphere eccentricities on impingement, range of motion (ROM), and muscle length during standard activities in reverse total shoulder arthroplasty (RSA).

Methods

In this study, we utilized computational modeling techniques to create native shoulder and shoulder models undergoing RSA and simulate shoulder movements in all abduction-adduction, flexion-extension, and rotation. We tested a total of 36 different glenosphere configurations, which included three different inferior tilts (0°, +10°, +20°) and two different lateral offsets (0 mm and +4 mm), as well as six different glenosphere eccentricities (concentricity, inferior, posterior, anterior, anteroinferior, and posteroinferior). We evaluated the maximum impingement-free ROM, impingement sites, and muscle lengths.

Results

All glenosphere configurations exceeded 50% of native shoulder ROM in three planes and total global ROM. In abduction-adduction, there was no significant difference among the different glenosphere eccentricities (p > 0.05). In flexion-extension, the posteroinferior eccentricity had the maximum ROM among the different eccentricities, but no significant difference among the different glenosphere eccentricities (p > 0.05). In rotation, there was a significant difference overall, and anteroinferior eccentricity had a significant advantage over concentricity (p < 0.05). In total global ROM, anteroinferior eccentricity had a significant advantage over concentricity when lateral offset was 0 mm (p < 0.05). In all models of glenosphere eccentricities, only the elongation of the infraspinatus muscle was statistically significant (p < 0.05).

Conclusion

Glenosphere eccentricity significantly influenced rotation, total global ROM, and the length of the subscapularis muscle. Among them, anteroinferior offset achieved the maximum ROM in abduction-adduction, rotation, and total global activities. Both anteroinferior and inferior glenoid eccentricity showed significant advantages over the concentricity in rotation and total global ROM.

Level of Evidence

Basic Science Study; Computer Modeling.

A deep surgical site infection risk score for patients with open tibial shaft fractures treated with intramedullary nail

OBJECTIVES

To identify deep infection risk factors in patients with open tibial shaft fractures and to develop a scoring algorithm to predict the baseline deep infection risk in this patient population.

METHODS

A retrospective cohort study conducted at a single academic trauma center identified patients with open tibial shaft fractures treated with intramedullary nail fixation from December 2006 to October 2020. The primary outcome was a deep surgical site infection requiring surgical debridement. The outcome was identified by Current Procedural Terminology codes and confirmed with a medical chart review documenting evidence of a tibial draining wound or sinus tract.

RESULTS

Deep surgical site infection occurred in 13% of patients (97/769). Factors that predicted deep surgical site infection were identified. Gustilo-Anderson type IIIB or IIIC was the strongest predictor with a 12-fold increase in the odds of deep infection (OR 11.8, p < 0.001). Additional factors included age >40 years (OR 1.7, p = 0.03), American Society of Anesthesiologists score ≥3 (OR 1.9, p < 0.01), Gustilo-Anderson type IIIA vs. type I or II (OR 2.8, p = 0.004), and gunshot wounds (OR 2.9, p = 0.02). The risk scoring model predicted patients who would develop an infection with an acceptable level of accuracy (AUC 0.79). The risk score categorized patients from a low probability of deep infection 2%-6% with <10 points to high risk (58%-69%) with >40 points.

CONCLUSIONS

This risk score model predicts deep postoperative infection in patients with open tibial shaft fractures treated with intramedullary nails. The ability to accurately estimate deep infection risk at the time of presentation might aid patient expectation management and allow clinicians to focus infection prevention strategies on the high-risk subset of this population.

The Role of Combined Inflammatory Biomarkers in the Diagnosis of High- and Low-Virulence FRI Among High-Risk Lower Extremity Fractures

Objective

The aim of this study is to evaluate the diagnostic accuracy of infection-related biomarkers in high-risk lower limb injury patients with fracture-related infection (FRI) caused by high-/low-virulence microorganisms.

Methods

This study was a retrospective analysis of patients with high-risk lower extremity fractures (including tibial plateau, calcaneus, and Pilon fractures) who underwent open reduction internal fixation (ORIF) surgery from January 2017 to February 2022. Peripheral blood samples were collected within 24 hours of admission, and the following information was evaluated: gender, age, BMI, smoking, comorbidities, injury information, surgical details, values for serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), as well as neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), and platelet-to-lymphocyte ratio (PLR).

Results

A total of 576 patients receiving lower extremity fracture surgery were included in this study. Fifty-one patients (8.85%) were identified as FRI, and 28 (54.9%) of these 51 cases were further classified as high-virulence group. The median levels of CRP, ESR, NLR, and MLR were significantly higher in the FRI group than in the non-FRI group (p < 0.01). Similarly, the marginally significantly higher levels of CRP and NLR presented in the high-virulence group, compared to the low-virulence group (p < 0.1). The AUC areas of CRP, NLR, and CRP+NLR were 0.826, 0.650, and 0.873, respectively. We calculated the optimal cut-off points for CRP+NLR as diagnostic markers of high-virulent infection was 0.377.

Conclusion

This study showed the incidence of FRI in high-risk lower extremity fractures was 8.9%, and identified preoperative serum biomarkers, including CRP, ESR, NLR, and PLR, as useful tools for assisting in the diagnosis of infection. Additionally, the combination of CRP with NLR played a discriminating clinical role in postoperative infections caused by different virulence.

Level of Evidence

Clinical study.

A Four-Probiotic Regime to Reduce Surgical Site Infections in Multi-Trauma Patients

Investigations that focused on the protective role of probiotics against Surgical Site Infections (SSI) in multiple-trauma (MT) patients are generally few, probably due to the complexity of the concept of trauma. We aimed to assess the efficacy of a four-probiotic regime to reduce the incidence of SSI in MT patients, with a brain injury included. MT patients, being intubated and expected to require mechanical ventilation for >10 days, were randomly allocated into placebo (n = 50) or probiotic treatment (n = 53) comprising Lactobacillus acidophilus LA-5 (1.75 × 109 cfu), Lactiplantibacillus plantarum UBLP-40 (0.5 × 109 cfu), Bifidobacterium animalis subsp. lactis BB-12 (1.75 × 109 cfu), and Saccharomycesboulardii Unique-28 (1.5 × 109 cfu) in sachets. All patients received two sachets of placebo or probiotics twice/day for 15 days and were followed-up for 30 days. The operations were classified as neurosurgical, thoracostomies, laparotomies, orthopedics, and others; then, the SSI and the isolated pathogen were registered. A total of 23 (46.0%) and 13 (24.5%) infectious insults in 89 (50 placebo patients) and 88 (53 probiotics-treated) operations (p = 0.022) were recorded, the majority of them relating to osteosynthesis—17 and 8, respectively. The most commonly identified pathogens were Staphylococcus aureus and Acinetobacter baumannii. Our results support published evidence that the prophylactic administration of probiotics in MT patients exerts a positive effect on the incidence of SSI.

Risk factors associated with surgical site infections following joint replacement surgery: a narrative review

Background

Surgical site infection following joint replacement surgery is still a significant complication, resulting in repeated surgery, prolonged antibiotic therapy, extended postoperative hospital stay, periprosthetic joint infection, and increased morbidity and mortality. This review discusses the risk factors associated with surgical site infection.

Related risk factors

The patient-related factors include sex, age, body mass index (BMI), obesity, nutritional status, comorbidities, primary diagnosis, living habits, and scores of the American Society of Anesthesiologists physical status classification system, etc. Surgery-related factors involve preoperative skin preparation, prolonged duration of surgery, one-stage bilateral joint replacement surgery, blood loss, glove changes, anti-microbial prophylaxis, topical anti-bacterial preparations, wound management, postoperative hematoma, etc. Those risk factors are detailed in the review.

Conclusion

Preventive measures must be taken from multiple perspectives to reduce the incidence of surgical site infection after joint replacement surgery.

Are deep infections that present before and after 90 days from orthopaedic trauma different? An analysis of the validity of the recent change in CDC criteria for infections

BACKGROUND

In 2016, the Centers for Disease Control and Prevention (CDC) changed the time frame for their definition of deep surgical site infection (SSI) from within 1 year to within 90 days of surgery. We hypothesized that a substantial number of infections in patients who have undergone fracture fixation present beyond 90 days and that there are patient or injury factors that can predict who is more likely to present with SSI after 90 days.

METHODS

A retrospective review yielded 452 deep SSI after fracture fixation. These patients were divided into two groups-those infected within 90 days of surgery and those infected beyond 90 days . Data were collected on risk factors for infection. Univariate and multiple logistic regression analyses were performed to compare the two groups. A randomly selected control group was used to build infection prediction models for both outcomes. The two outcomes were then modelled against each other to determine whether differences in predictors for early versus late infection exist.

RESULTS

Of the 452 infections, 144 occurred beyond 90 days (32% [95% CI, 28%-36%]). No statistically significant patient factors were found in multivariable analysis between the early and late infection groups. The need for flap coverage was the only injury characteristic that differed significantly between groups, with patients in the late infection group more likely to have needed a flap. When modelled against the control group and directly comparing the two models, predictors for early infection include male sex and fractures of the pelvis, acetabulum, or hip, whereas predictors of late infection include hepatitis C and/or human immunodeficiency virus (HIV) and admission to the intensive care unit (ICU).

CONCLUSION

Use of the recent CDC definition will underestimate the rate of actual postoperative infections when applied to orthopaedic trauma patients. Hepatitis C and/or HIV and ICU admission are predictors of late infection, whereas male sex and pelvis, acetabulum, or hip fractures are predictors of early infection. Patients who receive flap coverage may be more likely to present with late infection.

Admission Hyperglycemia Is a Risk Factor for Deep Surgical-Site Infection in Orthopaedic Trauma Patients

OBJECTIVES

To evaluate the association of admission blood glucose ≥200 mg/dL and surgical site infection in orthopaedic trauma surgery.

DESIGN

Retrospective, case control study.

SETTING

Academic trauma center.

PATIENTS

Four hundred sixty-five nondiabetic, noncritically ill orthopaedic trauma patients with an extremity, pelvic, or acetabular fracture and requiring open reduction and internal fixation or intramedullary nailing.

INTERVENTION

None.

MAIN OUTCOME MEASUREMENTS

Ninety-day deep surgical site infection.

RESULTS

Admission blood glucose ≥200 mg/dL was significantly associated with the primary outcome (8/128, 6.3% vs. 35/337, 1.8%; P = 0.01). Multivariable logistic regression modeling demonstrated that admission blood glucose ≥200 mg/dL was a significant risk factor for deep surgical site infections [odds ratio (OR): 4.7, 95% confidence interval (CI) 1.4-15.7], after controlling for male gender (OR: 1.8, 95% CI: 1.1-3.1), prior drug or alcohol abuse (OR: 1.9, 95% CI 0.9-4.0), open fracture (OR: 6.4, 95% CI 3.7-11.0), and fracture region (upper extremity OR: reference; pelvis/hip OR: 3.9, 95% CI 1.6-9.7; femur OR: 2.0, 95% CI 0.88-4.8; tibia/ankle OR: 3.3, 95% CI 1.7-6.2; and foot OR: 2.7, 95% CI 1.2-6.3).

CONCLUSIONS

Admission glucose ≥200 mg/dL was a significant independent risk factor for 90-day deep surgical site infections in orthopaedic trauma patients and may serve as an important marker for infection risk.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Risk factors for treatment failure of fracture-related infections

OBJECTIVE

Infection after fracture fixation is a potentially devastating outcome, and surgical management is frequently unsuccessful at clearing these infections. The purpose of this study is to determine if factors can be identified that are associated with treatment failure after operative management of a deep surgical site infection.

METHODS

We retrospectively reviewed the billing system at a Level I trauma center between March 2006 and December 2015. We identified 451 patients treated for deep surgical site infection after fracture fixation at our center. A multivariate regression analysis was then performed to evaluate for factors associated with treatment failure.

RESULTS

Mean follow-up was 2.3 years. One hundred fifty-six patients (35%) failed initial surgical management. Risk factors associated with treatment failure included initial culture results positive for polymicrobial organisms (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.0-2.4), removal of implants (OR, 1.9; 95% CI, 1.2-2.9), or Gustilo-Anderson IIIB/IIIC injury (OR, 2.0; 95% CI, 1.1-3.7). Increased body mass index and fulfilling the criteria to have a methicillin-resistant Staphylococcus aureus (MRSA) nasal swab screening showed a trend toward increased risk of failure.

CONCLUSION

Treatment failure after deep surgical site infection was relatively common. Three distinct factors (polymicrobial infection, removal of implants, and IIIB/C fracture) were associated with failure to eradicate the infection in the first series of surgeries and antibiotics. These data might help guide clinicians as they counsel patients on the risk of treatment failure and might focus efforts to improve treatment toward patients at higher risk of treatment failure.

A Predictive Risk Model for Infection-Related Hospitalization Among Home Healthcare Patients

Infection prevention is a high priority for home healthcare (HHC), but tools are lacking to identify patients at highest risk of developing infections. The purpose of this study was to develop and test a predictive risk model to identify HHC patients at risk of an infection-related hospitalization or emergency department visit. A nonexperimental study using secondary data was conducted. The Outcome and Assessment Information Set linked with relevant clinical data from 112,788 HHC admissions in 2014 was used for model development (70% of data) and testing (30%). A total of 1,908 patients (1.69%) were hospitalized or received emergency care associated with infection. Stepwise logistic regression models discriminated between individuals with and without infections. Our final model, when classified by highest risk of infection, identified a high portion of those who were hospitalized or received emergent care for an infection while also correctly categorizing 90.5% of patients without infection. The risk model can be used by clinicians to inform care planning. This is the first study to develop a tool for predicting infection risk that can be used to inform how to direct additional infection control intervention resources on high-risk patients, potentially reducing infection-related hospitalizations, emergency department visits, and costs.

The SIFK score: a validated predictive model for arthroplasty progression after subchondral insufficiency fractures of the knee

PURPOSE

The purpose of this study was to create a predictive model utilizing baseline demographic and radiographic characteristics for the likelihood that a patient with subchondral insufficiency fracture of the knee will progress to knee arthroplasty with emphasis on clinical interpretability and usability.

METHODS

A retrospective review of baseline and final radiographs in addition to MRIs were reviewed for evaluation of insufficiency fractures and associated injuries. Patient and radiographic factors were used in building predictive models for progression to arthroplasty with Train: Validation: Test subsets. Multiple models were compared with emphasis on clinical utility.

RESULTS

Total of 249 patients with a mean age of 64.6 (SD 10.5) years were included. Knee arthroplasty rate was 27% at mean of 4 years of follow-up. Lasso Regression was non-inferior to other models and was chosen for ease of interpretability. In order of importance, predictors for progression to arthroplasty included lateral meniscus extrusion, Kellgren-Lawrence Grade 4, SIFK on MFC, lateral meniscus root tear, and medial meniscus extrusion. The final SIFK Score stratified patients into low-, medium-, and high-risk categories with arthroplasty rates of 8.8%, 40.4%, and 78.9% (p < 0.001) and an area under the curve of 82.5%.

CONCLUSION

In this validated model, lateral meniscus extrusion, K-L Grade 4, SIFK on MFC, lateral meniscus root tear, and medial meniscus extrusion were the most important factors in predicting progression to arthroplasty (in that order). This model assists in patient treatment and counseling in providing prognostic information based on patient-specific risk factors by classifying them into a low-, medium-, and high-risk categories. This model can be used both by medical professionals treating musculoskeletal injuries in guiding patient decision making.

LEVEL OF EVIDENCE

Level III.

Incidence and risks for surgical site infection after closed tibial plateau fractures in adults treated by open reduction and internal fixation: a prospective study

Background

Surgical site infection (SSI) was the most common complication of tibial plateau fracture after open reduction and internal fixation (ORIF). Severe infections even required repeat surgeries, which would cause serious psychological harm to patients and increased the economic burden of treatment. In order to identify the characteristics of the SSI and to avoid the occurrence of SSI, we conducted a prospective study to investigate the incidence and independent risk factors of SSI after ORIF for closed tibial plateau fractures in adults.

Methods

This study was performed at a first-level trauma center. From October 2014 to December 2018, the study subjects were adult patients with closed fractures of the tibial plateau, all of whom underwent open reduction and internal fixation (ORIF) treatment. Finally, a total of 1108 patients were followed up. We collected patient demographics information, surgery-related variables, and indexes from preoperative laboratory examinations. Univariate and multivariate logistic analysis models were used to investigate the potential risk factors.

Results

Twenty-five patients (2.3%, 25/1108) developed SSI. A total of 15 of 25 infections (60.0%) were due to Staphylococcus aureus and 3 (12.0%) were due to MRSA. Independent risk factors of SSI identified by multivariate logistic analysis model were bone grafting: autograft (OR 6.38; 95% CI 2.155–18.886; p = 0.001) and allograft (OR 3.215; 95% CI 1.009–10.247; p = 0.048), fracture type (Schartzker V–VI) (OR 8.129; 95% CI 2.961–22.319; p < 0.001), aspartate aminotransferase (>40 U/L) (OR 5.500; 95% CI 2.191–13.807; p < 0.001), white blood cell (>10*10⁹/L) (OR 2.498; 95% CI 1.025–6.092; p = 0.044), and anion gap (>16 mmol/L) (OR 8.194; 95% CI 1.101–60.980).

Conclusions

We should pay enough attention to patients who carried one or more of these factors at admission and adopt more reasonable treatment strategies to reduce or avoid the occurrence of SSI.

Prognostic risk factors of surgical site infection after primary joint arthroplasty: A retrospective cohort study

Surgical site infection (SSI) can be a devastating complication in joint arthroplasty. Objective of this study was to identify potential risk factors associated with SSI following primary joint arthroplasty.This retrospective cohort study was performed from January 2016 to October 2017. A total of 986 patients were enrolled. We extracted the patients' baseline information, treatment-related variables and indexes of laboratory examination during their hospitalization. Receiver operating characteristic (ROC) analysis was performed to find the optimum cut-off value for serum albumin. Univariate and multivariate logistic analysis models were performed respectively to determine independent predictors of SSI.Nine hundred eighty-six patients with complete data were included in the final analysis. There were 314 male and 672 females in this study with a mean age of 64.6 years, and twenty patients developed SSI. The overall incidence of SSI was 2.03%, with 0.20% for deep infection and 1.83% for superficial SSI. Independent predictors of SSI identified by multivariate analysis were ALB < 36.7 g/L (odds ratio = 3.42; 95% CI = 1.24-9.48; P = .018), BMI ≥28 (odds ratio = 5.08; 95%CI = 1.52-17.01; P = .008) and ASA class 3 or higher (odds ratio = 3.36; 95% CI = 1.22-9.30; P = .019). Drain use was demonstrated as a protective factor of postoperative wound healing.The incidence of SSI following primary joint arthroplasty was 2.03%. ASA ≥3, BMI ≥28 and ALB < 36.7 g/L were demonstrated as risk factors of postoperative wound infection. Supplementary nutrition support is necessary to reduce the risk of infection in patients who underwent artificial joint arthroplasty.

A Predictive Score for Determining Risk of Surgical Site Infection After Orthopaedic Trauma Surgery

OBJECTIVES

To determine factors predictive of postoperative surgical site infection (SSI) after fracture fixation and create a prediction score for risk of infection at time of initial treatment.

DESIGN

Retrospective cohort study.

SETTING

Level I trauma center.

PATIENTS/PARTICIPANTS

Study group, 311 patients with deep SSI; control group, 608 patients.

INTERVENTION

We evaluated 27 factors theorized to be associated with postoperative infection. Bivariate and multiple logistic regression analyses were used to build a prediction model. A composite score reflecting risk of SSI was then created.

MAIN OUTCOME MEASURES

Risk of postoperative infection.

RESULTS

The final model consisted of 8 independent predictors: (1) male sex, (2) obesity (body mass index ≥ 30) (3) diabetes, (4) alcohol abuse, (5) fracture region, (6) Gustilo-Anderson type III open fracture, (7) methicillin-resistant Staphylococcus aureus nasal swab testing (not tested or positive result), and (8) American Society of Anesthesiologists classification. Risk strata were well correlated with observed proportion of SSI and resulted in a percent risk of infection of 1% for ≤3 points, 6% for 4-5 points, 11% for 6 to 8-9 points, and 41% for ≥10 points.

CONCLUSION

The proposed postoperative infection prediction model might be able to determine which patients have fractures at higher risk of infection and provides an estimate of the percent risk of infection before fixation.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Incidence and predictors of surgical site infection after ORIF in calcaneus fractures, a retrospective cohort study

BACKGROUND

Occurrence of calcaneus fractures is on the up trend. Owing to its unique anatomical morphology and limited soft-tissue envelope, management of calcaneus fractures is a challenge to the orthopaedic surgeon, and surgical site infection (SSI) is one of the serious postoperative complications. In order to decrease the incidence of wound breakdown and improve clinical outcomes, it is necessary to understand which factors were associated with SSI. The aim of this study was to identify predictors of SSI and quantify the incidence of SSI in calcaneus fractures following open reduction and internal fixation (ORIF).

METHODS

This retrospective study was performed at a level 1 trauma center from January 2014 to June in 2017. Data of adult patients with calcaneus fractures treated by ORIF were extracted from the electronic medical records. A total of 681 patients were collected. We reviewed the patients' demographics, characteristics of fracture, treatment-related variables, and indexes of laboratory examination. Univariate and multivariate logistic analysis models were performed respectively to determine independent predictors of SSI.

RESULTS

Sixty-six patients developed SSI in this study. The overall incidence of SSI after ORIF of calcaneus fracture was 9.7%, with 2.9% for deep infection and 6.8% for superficial SSI. Independent predictors of SSI identified by multivariate analysis were open fracture (odds ratio = 9.48, 95% CI = 4.53-19.85, P = 0.00007), high-energy injury (odds ratio = 2.07, 95% CI = 1.16-3.70, P = 0.01437), ASA class 3 or higher (odds ratio = 3.50, 95% CI = 1.18-10.37, P = 0.02401), and intraoperative temperature < 36.0 °C (odds ratio = 1.69, 95% CI = 1.13-2.28, P = 0.04410).

CONCLUSION

The SSI incidence was high (9.7%) for calcaneus fractures following ORIF. External fixation plays an important role in the treatment of severely displaced and depressed intra-articular or open calcaneus fractures. Increased ASA class and intraoperative hypothermia were associated with wound breakdown, and elaborative evaluation of fracture and soft-tissue damage was vitally necessary in this at-risk population.

Predicting nosocomial lower respiratory tract infections by a risk index based system

Although belonging to one of the most common type of nosocomial infection, there was currently no simple prediction model for lower respiratory tract infections (LRTIs). This study aims to develop a risk index based system for predicting nosocomial LRTIs based on data from a large point-prevalence survey. Among the 49328 patients included, the prevalence of nosocomial LRTIs was 1.70% (95% confidence interval [CI], 1.64% to 1.76%). The areas under the receiver operating characteristic (ROC) curve for logistic regression and fisher discriminant analysis were 0.907 (95% CI, 0.897 to 0.917) and 0.902 (95% CI, 0.892 to 0.912), respectively. The constructed risk index based system also displayed excellent discrimination (area under the ROC curve: 0.905 [95% CI, 0.895 to 0.915]) to identify LRTI in internal validation. Six risk levels were generated according to the risk score distribution of study population, ranging from 0 to 5, the corresponding prevalence of nosocomial LRTIs were 0.00%, 0.39%, 3.86%, 12.38%, 28.79% and 44.83%, respectively. The sensitivity and specificity of prediction were 0.87 and 0.79, respectively, when the best cut-off point of risk score was set to 14. Our study suggested that this newly constructed risk index based system might be applied to boost more rational infection control programs in clinical settings.

Local Antibiotic Therapy to Reduce Infection After Operative Treatment of Fractures at High Risk of Infection: A Multicenter, Randomized, Controlled Trial (VANCO Study)

A number of clinical studies in the spine literature suggest that the use of local vancomycin powder may substantially reduce surgical site infections (SSIs). These studies are primarily retrospective and observational and few focus on orthopaedic trauma patients. This study is a phase III, prospective, randomized, clinical trial to assess the efficacy of locally administered vancomycin powder in the prevention of SSI after fracture surgery. The primary goal of the VANCO Study is to compare the proportion of deep SSI 6 months after fracture fixation surgery. A secondary objective is to compare species and antibacterial susceptibilities among study patients who develop SSI. An additional objective is to build and validate a risk prediction model for the development of SSI. The study population consists of patients aged 18-80 years with tibial plateau or pilon (tibial plafond) fractures, at higher risk of infection, and definitively treated with plate and screw fixation. Participants are block randomized (within center) in a 1:1 ratio to either treatment group (local vancomycin powder up to a maximum dose of 1000 mg, placed immediately before wound closure) or control group (standard of care) for each study injury location, and return to the clinic for evaluations at 2 weeks, 3 months, and 6 months after fixation. The targeted sample size for the study is 500 fractures per study arm. This study should provide important information regarding the use of local vancomycin powder during the definitive treatment of lower extremity fractures and has the potential to significantly reduce the incidence of infection after orthopaedic trauma.

Supplemental Perioperative Oxygen to Reduce Surgical Site Infection After High-Energy Fracture Surgery (OXYGEN Study)

Supplemental perioperative oxygen (SPO) therapy has been proposed as one approach for reducing the risk of surgical site infection (SSI). Current data are mixed regarding efficacy in decreasing SSI rates and hospital inpatient stays in general and few data exist for orthopaedic trauma patients. This study is a phase III, double-blind, prospective randomized clinical trial with a primary goal of assessing the efficacy of 2 different concentrations of perioperative oxygen in the prevention of SSIs in adults with tibial plateau, pilon (tibial plafond), or calcaneus fractures at higher risk of infection and definitively treated with plate and screw fixation. Patients are block randomized (within center) in a 1:1 ratio to either treatment group (FiO2 80%) or control group (FiO2 30%) and stratified by each study injury location. Secondary objectives of the study are to compare species and antibacterial sensitivities of the bacteria in patients who develop SSIs, to validate a previously developed risk prediction model for the development of SSI after fracture surgery, and to measure and compare resource utilization and cost associated with SSI in the 2 study groups. SPO is a low cost and readily available resource that could be easily disseminated to trauma centers across the country and the world if proved to be effective.

Incidence of surgical site infections cannot be derived reliably from point prevalence survey data in Dutch hospitals

Thorough studies on whether point prevalence surveys of healthcare-associated infections (HAIs) can be used to reliably estimate incidence of surgical site infections (SSIs) are scarce. We examined this topic using surveillance data of 58 hospitals that participated in two Dutch national surveillances; HAI prevalence and SSI incidence surveillance, respectively. First, we simulated daily prevalences of SSIs from incidence data. Subsequently, Rhame & Sudderth's formula was used to estimate SSI incidence from prevalence. Finally, we developed random-effects models to predict SSI incidence from prevalence and other relevant variables. The prevalences simulated from incidence data indicated that daily prevalence varied greatly. Incidences calculated with Rhame & Sudderth's formula often had values below zero, due to the large number of SSIs occurring post-discharge. Excluding these SSIs, still resulted in poor correlation between calculated and observed incidence. The two models best predicting total incidence and incidence during initial hospital stay both performed poorly (proportion of explained variance of 0·25 and 0·10, respectively). In conclusion, incidence of SSIs cannot be reliably estimated from point prevalence data in Dutch hospitals by any of the applied methods. We therefore conclude that prevalence surveys are not a useful measure to give reliable insight into incidence of SSIs.

Diabetes and Risk of Surgical Site Infection: A Systematic Review and Meta-analysis

OBJECTIVE To determine the independent association between diabetes and surgical site infection (SSI) across multiple surgical procedures. DESIGN Systematic review and meta-analysis. METHODS Studies indexed in PubMed published between December 1985 and through July 2015 were identified through the search terms "risk factors" or "glucose" and "surgical site infection." A total of 3,631 abstracts were identified through the initial search terms. Full texts were reviewed for 522 articles. Of these, 94 articles met the criteria for inclusion. Standardized data collection forms were used to extract study-specific estimates for diabetes, blood glucose levels, and body mass index (BMI). A random-effects meta-analysis was used to generate pooled estimates, and meta-regression was used to evaluate specific hypothesized sources of heterogeneity. RESULTS The primary outcome was SSI, as defined by the Centers for Disease Control and Prevention surveillance criteria. The overall effect size for the association between diabetes and SSI was odds ratio (OR)=1.53 (95% predictive interval [PI], 1.11-2.12; I2, 57.2%). SSI class, study design, or patient BMI did not significantly impact study results in a meta-regression model. The association was higher for cardiac surgery 2.03 (95% PI, 1.13-4.05) compared with surgeries of other types (P=.001). CONCLUSIONS These results support the consideration of diabetes as an independent risk factor for SSIs for multiple surgical procedure types. Continued efforts are needed to improve surgical outcomes for diabetic patients. Infect. Control Hosp. Epidemiol. 2015;37(1):88-99.

Evaluating the use of antibiotic prophylaxis during open reduction and internal fixation surgery in patients at low risk of surgical site infection

BACKGROUND

Widespread overuse and inappropriate use of antibiotics contribute to increasingly antibiotic-resistant pathogens and higher health care costs. It is not clear whether routine antibiotic prophylaxis can reduce the rate of surgical site infection (SSI) in low-risk patients undergoing orthopaedic surgery. We designed a simple scorecard to grade SSI risk factors and determined whether routine antibiotic prophylaxis affects SSI occurrence during open reduction and internal fixation (ORIF) orthopaedic surgeries in trauma patients at low risk of developing SSI.

METHODS

The SSI risk scorecard (possible total points ranged from 5 to 25) was designed to take into account a patient's general health status, the primary cause of fractures, surgical site tissue condition or wound class, types of devices implanted, and surgical duration. Patients with a low SSI risk score (≤8 points) who were undergoing clean ORIF surgery were divided into control (routine antibiotic treatment, cefuroxime) and evaluation (no antibiotic treatment) groups and followed up for 13-17 months after surgery.

RESULTS

The infection rate was much higher in patients with high SSI risk scores (≥9 points) than in patients with low risk scores assigned to the control group (10.7% vs. 2.2%, P<0.0001). SSI occurred in 11 of 499 patients in the control group and in 13 of 534 patients in the evaluation group during the follow-up period of 13-17 months. The SSI occurrence rate did not differ significantly (2.2% vs. 2.4%, P=0.97) between the control and evaluation groups.

CONCLUSIONS

Routine antibiotic prophylaxis does not significantly decrease the rate of SSI in ORIF surgical patients with a low risk score. Implementation of this scoring system could guide the rational use of perioperative antibiotics and ultimately reduce antibiotic resistance, health care costs, and adverse reactions to antibiotics.

Perioperative supplemental oxygen to reduce surgical site infection after open fixation of high-risk fractures: a randomized controlled pilot trial

BACKGROUND

Higher concentrations of fraction of inspired oxygen (FIO2) have been shown to be associated with lower risk for surgical site infection in multiple studies outside the domain of orthopedic surgery. We evaluated the efficacy of high FIO2 administered during the perioperative period to reduce the rate of surgical site infection after open fixation of lower-extremity fractures at high risk of infection.

METHODS

We conducted a randomized controlled, parallel design, double-blind study. Patients sustaining high-energy tibial plateau, tibial pilon, and calcaneus fractures treated in a staged fashion were selected for enrollment because these injuries are associated with high risk of infection. The study population included 222 patients with 235 fractures. Consenting patients were randomized by random number sequence to either the treatment or the control group. Treatment group patients received 80% FIO2 intraoperatively and for 2 hours afterward. Control group patients received 30% FIO2 during the same period. Surgeons, patients, and personnel who performed wound assessments were blinded to group assignment. The primary outcome measure was surgical site infection as defined by the Centers for Disease Control criteria for postoperative wound infection.

RESULTS

The overall rates of postoperative surgical site infection were 12% (14 of 119 fractures) in the treatment group and 16% (19 of 116 fractures) in the control group (p = 0.31). Multivariate analysis, accounting for risk factors for infection, yielded the closest to a statistically significant reduction in the odds of infection with treatment (odds ratio, 0.54; p = 0.17). No treatment-associated events were observed.

CONCLUSION

Use of a high concentration of FIO2 during the perioperative period is safe and shows a trend toward reduction of surgical site infection in patients undergoing open operative fixation of high-energy traumatic lower-extremity fractures. Further study in a larger patient population is indicated.

LEVEL OF EVIDENCE

Therapeutic study, level III.