Patient-related factors associated with superficial surgical site infection and progression to a periprosthetic joint infection after elective primary total joint arthroplasty: a single-centre, retrospective study in Sweden

Difficulty of diagnostic accuracy of periprosthetic joint infection: a retrospective analysis of revision surgery of total hip arthroplasty and total knee arthroplasty in a tertiary hospital

BACKGROUND

Diagnostic accuracy of periprosthetic joint infection still remains controversial and an unsolved problem with respect to clinical signs and laboratory measures. Influencing factors of diagnosis like age, sex, abnormal physical findings and comorbidities are published with different results. The aim of our study was to find factors strengthening the diagnosis.

METHODS

We therefore retrospectively investigated all revision surgeries of total knee arthroplasty and total hip arthroplasty in the years 2019 and 2020 in a tertiary hospital with special regard to diagnostic accuracy of periprosthetic joint infection and switch in diagnosis to aseptic mechanical loosening or vice versa. All patients were divided into 4 non-hierarchical groups: suspected and discharge diagnosis periprosthetic joint infection (P1), suspected and discharge diagnosis mechanical loosening (P2), suspected diagnosis mechanical loosening and discharge diagnosis periprosthetic joint infection (P3), suspected diagnosis PJI and discharge diagnosis mechanical loosening (P4).

RESULTS

In the years 2019-2020, 106 patients underwent revision surgery of total knee arthoplasty and total hip arthroplasty. 33 patients showed periprosthetic joint infection (31.1%) according to Infectious Diseases Society (IDSA) criteria, 73 patients showed mechanical loosening (68.9%). Of the periprosthetic joint infection -patients, 15 were men (46%) and 18 were women (54%). The patients with mechanical loosening were 27 men (37%) and 46 women (63%). In group P1 (25 patients), 22 could be classified according to the histopathological classification Krenn and Morawietz grade 2 and grade 3, 2 patients to grade 4 and one patient could not be classified. In group P3 (8 patients) all could be classified according to the classification Krenn and Morawietz grade 2 and 3. Groups P1 - P4 were correlated with categorial basic data: All Groups P1 - P4 showed a statistical correlation towards American Society of Anesthesiologists (ASA) categorization 3-4 versus ASA 2 (p = 0.01). In the pairwise comparison in the exact Fisher´s exact test P1 and P2 showed a statistical correlation towards ASA categorization 3-4 versus ASA 2 (p = 0.01). Charlson Comorbidity Index (CCI) categories 5-7 versus 0,1-2 and 3-4 showed a statistical correlation towards groups P1-P4 (p = 0.007) and in the pairwise comparison in the exact Fisher´s exact test a discrimination of P1 and P2 (p = 0.001) and P1 and P3 (p = 0.007). The preoperative corticoid therapy showed a statistical correlation to groups P1-P4 (p = 0.05) and in the pairwise comparison in the exact Fisher test a discrimination of P1 and P4 (p = 0.02).

CONCLUSION

We therefore conclude that diagnosis of periprosthetic joint infection still remains difficult. Switches in diagnosis during hospital stay from periprosthetic joint infection to aseptic mechanical loosening and vice versa are not unusual and the role of different diagnostic tools needs further investigation. Patients categorized according to ASA and CCI as severely ill might be more likely to be diagnosed correctly with periprosthetic joint infection.

How reliable is the soft tissue radiological knee index in predicting superficial surgical site infection following total knee arthroplasty?

INTRODUCTION

The purpose of this study was to evaluate the association between the Soft Tissue Radiological Knee (SToRK) Index and the risk of developing a superficial surgical site infection (SSSI) following primary total knee arthroplasty (TKA).

METHODS

The SToRK Index was measured using calibrated long leg radiographs (LLR) in 174 patients undergoing TKA.

RESULTS

A moderate correlation was found between the SToRK Index and body mass index (BMI) (rs=0.574; p < 0.001). The SToRK Index was a better predictor of SSSI in females than males. In females, a SToRK Index cutoff of 2.01 had a sensitivity and specificity of 41.3% and 74.6% for developing SSSI, respectively, with a positive likelihood ratio of 1.63.

CONCLUSION

The SToRK Index can be used as an additional tool in assessing the risk for SSSI after TKA. It might be more predictive in females due to the different fat distribution compared to males.

Adverse effect of smoking on surgical site infection following ankle and calcaneal fracture fixation: a meta-analysis

Purpose

Studies have reported conflicting findings on the relationship between smoking and surgical site infection (SSI) post fixation for ankle and calcaneal fractures. This meta-analysis explored the effect of smoking on SSI incidence following open reduction and internal fixation (ORIF) of these fractures.

Methods

Full-text studies on smoking's influence on post-ORIF SSI rates for closed ankle and calcaneal fractures were sourced from the PubMed, Embase, and Cochrane databases, with no consideration given to language or publication date. Study quality was appraised using the Newcastle-Ottawa Scale. Odds ratios (OR) and the corresponding 95% CIs were determined using random-effects models. This meta-analysis adhered to the PRISMA guidelines and was registered with PROSPERO (CRD42023429372).

Results

The analysis incorporated data from 16 cohort and case-control studies, totaling 41 944 subjects, 9984 of whom were smokers, with 956 SSI cases. Results indicated smokers faced a higher SSI risk (OR: 1.62; 95% CI: 1.32-1.97, P < 0.0001) post ORIF, with low heterogeneity (I 2 = 26%). Smoking was identified as a significant deep SSI risk factor (OR: 2.09; 95% CI: 1.42-3.09; P = 0.0002; I 2 = 31%). However, the subgroup analysis revealed no association between smoking and superficial SSI (OR: 1.05; 95% CI: 0.82-1.33; P = 0.70; I 2 = 0%).

Conclusion

Smoking is associated with increased SSI risk after ORIF for closed ankle and calcaneus fractures. Although no clear link was found between superficial SSI and smoking, the data underscore the negative influence of smoking on deep SSI incidence.

Preoperative optimization of modifiable risk factors is associated with decreased superficial surgical site infections after total joint arthroplasty: a prospective case-control study

BACKGROUND AND PURPOSE

The aim of our study was to investigate change in modifiable risk factors following preoperative optimization and whether risk of superficial surgical site infection (SSI) after total joint arthroplasty (TJA) could be reduced.

METHODS

This is a prospective study of implementation of a preoperative optimization pathway for patients waiting for primary TJA. Information regarding the intervention arm was collected from January 2019 to January 2021, first at decision for operation and then at preoperative assessment 1 week prior to operation. The control arm was included between August 2018 and September 2020 after receiving conventional preoperative preparation and information gathered at preoperative assessment. Follow up occurred 6 weeks postoperatively for both groups. The primary outcome was postoperative superficial SSI.

RESULTS

The optimization effort resulted in improvement of weight, anemia, HbA1c, vitamin D, and patient engagement. At preoperative assessment the baseline characteristics of the 2 groups were similar except that the intervention group had substantially more comorbidities. Regarding superficial SSI, association was found with BMI ≥ 30 and HbA1c ≥ 42 mmol/mol in the control group but not in the intervention group. When corrected for differences in ASA classification (reflecting comorbidities), age, and sex, being in the intervention group was associated with lower odds of occurrence of superficial SSI compared with the control group (OR 0.64, 95% confidence interval 0.42-0.97).

CONCLUSION

We showed that preoperative optimization in a structured cooperation between hospital and primary care was associated with a reduced risk of superficial SSI.

The Incidence and Risk Factors of Early Periprosthetic Joint Infections

Objective

Periprosthetic joint infections (PJI) represent major complications in arthroplasty, contributing to increased patient morbidity and imposing substantial financial burdens. Meticulous surveillance of PJI occurrences and identification of associated risk factors is imperative for accurately gauging the incidence rates and implementing proactive infection control measures. This study aimed to ascertain the early incidence of PJI and elucidate the key risk factors involved in its occurrence.

Materials and Methods

This monocentric, prospective descriptive study conducted between June 2018 and June 2019, including all patients aged 18 years and above who underwent hip and knee arthroplasty. The research documented and evaluated patient demographic characteristics, clinical findings, laboratory results, treatment practices, and potential risk factors associated with the surgical process. After the 90-day postoperative period, patients were categorized into PJI and non-PJI groups, allowing for a comprehensive comparison of identified risk factors.

Results

This study identified a cohort of 590 patients, of whom 185 underwent hip arthroplasties (31.4%) and 405 underwent knee arthroplasties (68.6%). The average age of the patients was 65.2 years, with females constituting 80.2% of the population. The overall incidence of early PJI was found to be 2.88% (n=17). Following hip arthroplasties, the PJI incidence was 4.86%, while knee arthroplasties exhibited a lower incidence of 1.9%. Several potential risk factors associated with PJI were identified, including comorbid diseases (adjusted odds ratio [aOR]=3.35, 95% confidence interval [CI]=1.18-9.47), preoperative length of stay (aOR=0.89, 95% CI=0.79-1.01), postoperative erythrocyte suspension replacement (aOR=1.96, 95% CI=0.71-5.44), and a National Nosocomial Infections Surveillance System (NNIS) score of 1 or higher (aOR=3.10, 95% CI=1.10-8.71). These factors were identified as potential contributors to the risk of PJI in patients undergoing hip and knee arthroplasties.

Conclusion

Compared to other reported outcomes in the literature, this study observed a higher incidence of early-stage PJI. The higher incidence may be due to PJI surveillance deficiencies such as difficulty in post-discharge surgical site infection (SSI) follow-up, reporting, and bacterial sampling. This discrepancy underscores the importance of actively monitoring patients with risk factors for PJI development, including medical comorbidities and a high NNIS score. Implementing prospective active surveillance in such cases is deemed crucial for the timely identification and management of PJI.

Evaluation of risk factors for surgical site infections in osteoarthritis patients undergoing total knee arthroplasty

This research sought to delineate risk factors associated with surgical site infections (SSIs) post-total knee arthroplasty (post-TKA) in elderly osteoarthritis patients, aiming to enhance post-surgical outcomes. A retrospective examination was conducted on a cohort of 650 elderly patients who underwent unilateral TKA between January 2018 and August 2022. Data procurement was from the hospital's Electronic Health Record, and a comprehensive statistical evaluation was performed using IBM SPSS Statistics version 24.0. Both univariate and multivariate techniques assessed a spectrum of risk determinants such as age, body mass index (BMI), coexisting medical conditions and surgical variables. The univariate examination spotlighted age, BMI, diabetes prevalence, chronic corticosteroid consumption and American Society of Anesthesiologists (ASA) physical status classification as notable predictors of SSIs. The multivariate logistic regression pinpointed age, BMI, history of smoking and diabetes diagnosis as salient risk attributors for post-TKA infections. Concurrently, parameters like ASA classification, surgical duration and intraoperative haemorrhage further enriched the risk landscape. Geriatric patients undergoing TKA for knee osteoarthritis manifest a tangible infection susceptibility post-surgery. Precision interventions concentrating on amendable risk components, including meticulous preoperative evaluations and strategic postoperative care, are imperative to attenuate SSI incidence, thereby amplifying surgical efficacy and optimizing patient recuperation trajectories.

Utility of Thermal Imaging in Predicting Superficial Infections in Transfemoral Osseointegrated Implants

Background

Superficial infection is a common minor complication of transcutaneous implants that can be challenging to predict or diagnose. Although it remains unclear whether superficial infections progress to deep infections (which may require implant removal), predicting and treating any infection in these patients is important. Given that flap thinning during stage II surgery requires compromising vascularity for stability of the skin penetration aperture, we hypothesized that early skin temperature changes predict long-term superficial infection risk.

Methods

We obtained standardized thermal imaging and recorded surface temperatures of the aperture and overlying flaps 2 weeks postoperatively for the first 34 patients (46 limbs) treated with the Osseointegrated Prosthesis for the Rehabilitation of Amputees transfemoral implant system. We used two-sided t tests to compare temperatures surrounding the aperture and adjacent soft tissues in patients with and without subsequent infection.

Results

During median follow-up of 3 years, 14 limbs (30.4%) developed 23 superficial infections. At patients' initial 2-week visit, mean skin temperature surrounding the aperture was 36.3ºC in limbs that later developed superficial infections and 36.7ºC in uninfected limbs (P = 0.35). In four patients with bilateral implants who later developed superficial infection in one limb, average temperature was 1.5ºC colder in the infected limb (P = 0.12).

Conclusions

Superficial infections remain a frequent complication of transfemoral osseointegration surgery. We did not find differences in early heat signatures between limbs subsequently complicated and those not complicated by superficial infection. Further research should explore more objective measures to predict, diagnose, and prevent infections after osseointegration surgery.

Post-discharge occurrence of surgical site infections after hip or knee arthroplasty surgery in Poland, a population-based study

Arthroplasty is a common procedure improving functioning of patients and their quality of life. Infection is a serious complication that determines subsequent management of the prosthesis and the patient. The aim of the study was to investigate the incidence of post-discharge surgical site infections (SSI) and their risk factors. A retrospective analysis of an anonymized database from the National Health Found for 2017 of 56,068 adult patients undergoing hip replacement surgery (HPRO) and 27,457 patients undergoing knee replacement surgery (KPRO). The cumulative incidence of post-discharge SSI was 0.92% for HPRO and 0.95% for KPRO. The main risk factors for hip SSI were male gender, diseases of hematopoietic, musculoskeletal and nervous system. The risk factor for knee SSI was male gender. All comorbidities significantly increased the risk of SSI. The ICU stay and antibiotics administered at discharge in studied population increased the risk of detection of SSI after HPRO and KPRO by up to four and seven times, respectively. For both procedures rehabilitation after surgery and total endoprosthesis decreased incidence of SSIs. The lower experience of the center was related to higher SSI incidence in HPRO in primary (1.5% vs. 0.9%) and in revision surgeries (3.8% vs. 2.1%), but in KPRO, lower experience only in primary surgeries was significantly associated with SSI. The cumulative incidence of post-discharge SSI in Poland is higher than in other European countries. Special attention should be paid to patients with chronic diseases.

Prevalence of modifiable risk factors in primary elective arthroplasty and their association with infections

BACKGROUND AND PURPOSE

The aim of this study was to identify the prevalence of modifiable risk factors of surgical site infections (SSI) in patients undergoing primary elective total joint arthroplasty (TJA) receiving conventional preoperative preparation, and to explore their association with infectious outcomes.

PATIENTS AND METHODS

Information regarding modifiable risk factors (anemia, diabetes, obesity, nutritional status, smoking, physical activity) was prospectively gathered in patients undergoing primary TJA of hip or knee in 2018-2020 at a single institution with 6 weeks' follow-up time.

RESULTS

738 patients (median age 68 years [IQR 61-73], women 57%) underwent TJA (knee 64%, hip 36%). Anemia was detected in 8%, diabetes was present in 9%, an additional 2% had undiagnosed diabetes (HbA1c > 47 mmol/mol), and 8% dysglycemia (HbA1c 42-47 mmol/mol). Obesity (BMI ≥ 30) was observed in 52%. Serum albumin, total lymphocyte count, and vitamin D below normal limits was identified in 0.1%, 18%, and 16%, respectively. Current smokers were 7%. Surgical site complications occurred in 116 (16%), superficial SSI in 57 (8%), progressing to periprosthetic joint infection in 7 cases. Univariate analysis identified higher odds of superficial SSI for BMI ≥ 30 (OR 2.1, 95%CI 1.2-3.8) and HbA1c ≥ 42 mmol/mol (OR 2.2, CI 1.1-4.2), but no association was found with other factors.

CONCLUSION

In a general population undergoing primary TJA an association was found between obesity (52%) and dysglycemia/diabetes (19%) and superficial SSI (8%), which progressed to PJI in 12% of cases, generating a 1% total rate of PJI. Modification of these risk factors might mitigate infectious adverse outcomes.