Osteoporosis, a prevalent bone density disorder, introduces a complex dynamic in the context of total shoulder arthroplasty (TSA). However, despite the well-established association between osteoporosis and an elevated risk of revision, the existing literature lacks comprehensive insights into the impact of anti-osteoporotic therapy on surgical outcomes in the setting of TSA. Thus, the purpose of this study was to investigate whether anti-osteoporotic therapy correlates with improved revision outcomes following TSA.

A retrospective cohort analysis was performed using a national all payer's claims database. Patients who underwent TSA were identified using Current Procedural Terminology and International Classification of Diseases procedure codes. Patients with a preoperative diagnosis of osteoporosis were included and stratified into 2 groups: (1) patients with osteoporosis who underwent anti-osteoporotic therapy within 6 months prior to surgery (anti-OP cohort) and (2) patients with osteoporosis who never received anti-osteoporotic treatment (no anti-OP cohort). Primary outcomes included the incidence of 2-year all-cause revision, periprosthetic fracture, periprosthetic joint infection, and mechanical loosening. Univariate and multivariable regression analysis was conducted to compare outcomes between the 2 cohorts.

In total, 40,532 osteoporotic patients were included in this study, with 11,577 (28.5%) having undergone anti-osteoporotic treatment. Patients who did not receive anti-osteoporotic treatment had significantly higher odds of 2-year all-cause revision (odds ratio: 1.31; P < .001) and mechanical loosening (odds ratio: 1.25; P < .001) following TSA when compared to those treated for osteoporosis.

This study demonstrates a significant association between anti-osteoporotic therapy and reduced rates of 2-year revision following TSA. Orthopedic surgeons should recognize the heightened risk of early implant failure in the absence of osteoporosis therapy. This underscores the imperative for increased screening initiatives given the high prevalence of undiagnosed or untreated osteoporosis in the TSA population. These results also emphasize the importance of integrating osteoporosis management strategies into the broader context of surgical decision-making, thereby contributing to enhanced patient outcomes and quality of care in shoulder surgery.

This study aimed to identify the risk factors and microbial profiles of patients with culture-negative periprosthetic joint infection (PJI) using metagenomic next generation sequencing (mNGS) and to compare the clinical characteristics and treatment outcomes of culture-negative PJI (CN PJI) with culture-positive PJI (CP PJI).

A retrospective analysis was conducted on 223 patients who met the International Consensus Meeting criteria for PJI and underwent surgical treatment at our hospital between February 2013 and January 2023. Clinical and follow-up data, including microbiological culture results and mNGS findings, were collected. Based on culture results, patients were divided into the CP PJI and CN PJI groups. Risk factors and microbial profiles of CN PJI patients were summarized with the aid of mNGS results. Differences in clinical characteristics and treatment outcomes between the two groups were also analyzed.

Among the 223 patients, 168 were in the CP PJI group, and 55 were in the CN PJI group. Risk factors for negative cultures included polymicrobial infections, infections caused by rare pathogens, and prolonged antibiotic use prior to sampling. In the CN PJI group, over a quarter of cases involved polymicrobial infections (25.5%) or rare pathogen infections (38.2%), with Mycoplasma sp. being the most frequently identified rare pathogen (7.2%). Compared to the CP PJI group, the CN PJI group exhibited distinctly longer hospital stays (P<0.001), extended antibiotic use (P=0.02), and a higher rate of antibiotic-related complications (P=0.026). However, no significant difference was noted in reinfection rates between the two groups (P=0.412).

CN PJI presents a unique microbial spectrum and distinct clinical therapeutic characteristics. mNGS offers a more comprehensive understanding of infecting microorganisms, particularly those often missed by conventional culture techniques. With advancements in sample collection, optimized culture methods, molecular diagnostic tools, and early targeted therapies, CN PJI may achieve clinical outcomes comparable to CP PJI.

Background and objective The diagnosis of periprosthetic joint infection (PJI) relies on established criteria-based systems requiring interpretation and combination of multiple laboratory tests into scoring systems. In routine clinical care, clinicians implement these algorithms to diagnose PJI. Existing literature indicates suboptimal adoption and implementation of these criteria in clinical practice, even among experts. Recognizing the need for accurate PJI diagnosis through proper synthesis of multiple laboratory parameters, this study aimed to develop and validate a machine learning (ML) model that generates a preoperative PJI probability score based solely on synovial fluid (SF) biomarkers within 24 hours. Materials and methods A two-stage ML model was constructed using 104,090 SF samples from 2,923 institutions (2018-2024). First, unsupervised learning identified natural clusters in the data to label samples as "infected" or "not infected." Then, these labels trained a supervised logistic regression model that generated PJI scores (0-100), categorizing cases as PJI positive (> 80), PJI negative (< 20), or equivocal (20-80). The model incorporated 10 SF biomarkers: specimen integrity markers (absorbance at 280 nm, red blood cell count), inflammatory markers (white blood cell count, percentage of neutrophils, SF C-reactive protein), a PJI-specific biomarker (alpha-defensin), and microbial antigen markers (Staphylococcus, Enterococcus, Candida, and Cutibacterium acnes). Notably, culture results were excluded to allow for a 24-hour diagnosis. After splitting data into training (n = 83,272) and validation (n = 20,818) cohorts, performance was assessed against modified 2018 International Consensus Meeting criteria, including evaluation with probabilistically reclassified "inconclusive" cases. Results The ML model and resulting PJI score showed high diagnostic accuracy in the validation cohort. The PJI score achieved 99.3% sensitivity and 99.5% specificity versus the clinical reference before reclassification of inconclusive cases and 98.1% sensitivity and 97.6% specificity after probabilistic reclassification. With a disease prevalence of 20.7%, the positive predictive value reached 91.5% and the negative predictive value 99.5%. The model resolved 95% (1,363/1,442) of samples deemed inconclusive by the clinical standard. The analysis identified alpha defensin, percentage of neutrophils, and white blood cell count as the most influential model features. The model performed well in culture-negative infections. Conclusions The ML model and resulting PJI score demonstrated exceptional diagnostic accuracy by leveraging unsupervised SF biomarker pattern clustering. The model substantially reduced diagnostic uncertainty by definitively classifying most inconclusive cases, revealing their natural alignment with infected or non-infected patterns. This performance was achieved without SF culture results, enabling definitive diagnostic information within 24 hours based solely on biomarkers. The clinical significance demonstrates that an ML algorithm can match the diagnostic accuracy of complex clinical standards while transferring analytical complexity from clinicians to laboratories, minimizing the implementation gap that hinders current criteria-based approaches.

The purpose of this study was to predict high-risk patients who experience significant increases in hospital charges and length of stay (LOS) following specific postoperative complications.

This study analyzed over two million patients from the Nationwide Inpatient Sample database undergoing elective total knee arthroplasty (TKA) for primary osteoarthritis. Baseline demographics, clinical characteristics and incidence of postoperative complications were examined. A neural network model was utilized to predict high-risk patients who fall into the top 25% for both LOS and total hospital charges after complications such as sepsis or surgical site infection (SSI).

The most common complications were blood loss anaemia (14.6%), acute kidney injury (1.6%) and urinary tract infection (0.9%). Patients with complications incurred significantly higher total charges (mean $66,804) and longer LOS (mean 2.9 days) compared to those without complications (mean $58,545 and 2.1 days, respectively). The neural network model demonstrated strong predictive performance, with an area under the curve of 0.83 for the training set and 0.78 for the testing set. Key complications like sepsis and SSIs significantly impacted hospital charges and LOS. For example, a 57-year-old patient with diabetes and sepsis had a 100% probability of being in the top 25% for both total charges and LOS.

Postoperative complications in TKA patients significantly increase hospital charges and LOS. The neural network model effectively predicted high-risk patients after specific complications occurred, offering a potential tool for improving patient management and resource allocation.

Level III.

This study aims to evaluate changes in the coagulation profile of patients with knee periprosthetic infections (PJI) and determine its diagnostic value in this complication.

A prospective study was conducted with 112 patients who underwent revision surgery for total knee arthroplasty in a single tertiary hospital between January 2021 and December 2022.

51 patients were diagnosed with PJI. D-dimer (p = 0.001), fibrinogen (p = 0.0007), platelets (0.01), and international normalized ratio (p = 0.01) were significantly higher in patients with PJI.

Patients with PJI display altered coagulation profile. The evaluation of coagulation-related markers has limited value for diagnosing PJI. Further studies are needed to understand the impact of such alterations on patients' outcomes.

Periprosthetic joint infections (PJI) remain a significant complication in total knee arthroplasty (TKA), often necessitating complex revisions. Vancomycin powder has been used intra-articularly to reduce PJI rates, but conflicting evidence suggests potential complications. This technical note introduces a novel approach: applying vancomycin powder beneath the polyethylene component during TKA, rather than directly into the joint space. We hypothesize that this technique could enhance infection prevention efficacy while minimizing complications associated with intra-articular vancomycin. We detail the indications, procedural steps, and potential complications of this method. Vancomycin powder is applied to the tibial surface before inserting the polyethylene component, maintaining the drug's proximity to potential infection sites without direct exposure to joint tissues. This approach aims to balance infection prevention with safety concerns, providing an alternative for patients at high risk for PJI. Further clinical validation is necessary to confirm the efficacy and safety of this technique.

Periprosthetic joint infections (PJIs) are one of the most devastating complications of total knee arthroplasty (TKA). Patients who have chronic kidney disease (CKD) are more vulnerable to PJI. We aimed to answer the following questions: 1) What are the commonly observed pathogens in PJI after TKA in CKD patients, and do they differ from those in non-CKD patients? and 2) What are the risk factors for PJI after TKA in CKD patients?

Patients who underwent surgery due to a chronic PJI of the TKA were retrospectively enrolled. The patients were divided into two groups as follows: patients those who had and those who did not have CKD. Demographic data and comorbidities of the patients were recorded. The microorganisms responsible for PJI were identified based on the biopsy results, and comparisons were made between the two groups. There were 331 patients in the CKD group and 2,238 in the control group. Patients who had CKD were significantly older (P < 0.001) and had higher Charlson Comorbidity Index scores (P < 0.001).

Binary logistic regression identified multiple microorganisms within the CKD group. The most common microorganisms in PJI were as follows: Staphylococcus epidermidis (odds ratio [OR] 1.38; P = 0.030; 95% confidence intervals (CI) 1.03 to 1.86), Staphylococcus aureus (OR 1.88; P < 0.001; 95% CI 1.36 to 2.61), Enterococcus faecalis (OR 2.39; P < 0.001; 95% CI 1.44 to 3.94), Escherichia coli (OR 1.76; P = 0.028; 95% CI 1.06 to 2.94), methicillin-resistant Staphylococcus aureus (OR 3.04; P = 0.024; 95% CI 1.15 to 8.02), polymicrobial infections (OR 1.52; P < 0.001; 95% CI 1.12 to 2.06).

Patients who had PJI and CKD demonstrated a higher incidence of infections with specific microorganisms, including Staphylococci, enterococci, gram-negative bacteria, and methicillin-resistant Staphylococcus aureus. To mitigate the high PJI risk in CKD patients, a treatment plan based on this microbial profile and a multidisciplinary assessment of CKD comorbidities before TKA is recommended.

Objective: This study aims to explore the predictive value of heparin-binding protein (HBP) in diagnosing prosthesis infections after total joint arthroplasty (TJA), in order to provide a new biomarker for early identification and management of prosthetic joint infections (PJI) post-TJA. Methods: A retrospective analysis of data from 168 patients who underwent TJA revision at Lianyungang First People's Hospital from October 2020 to March 2024 was conducted. The participants were divided into an infection group (38 cases) and a non-infection group (94 cases). Inclusion criteria included all patients undergoing joint prosthesis revision who had preoperative HBP levels measured. Primary assessment parameters included HBP, C-reactive protein (CRP), white blood cell (WBC) count, and erythrocyte sedimentation rate (ESR). Univariate analysis and multivariate regression analysis were used to evaluate the correlation of these factors with PJI, and the performance of HBP in predicting PJI was analyzed using the receiver operating characteristic (ROC) curve. Results: There were significant statistical differences in HBP, CRP, WBC, and ESR between the infection and non-infection groups (p < 0.05). Multivariate regression analysis showed that HBP is an independent predictive factor for the risk of PJI. The area under the ROC curve was 0.856, indicating that HBP has good predictive performance. The optimal cutoff value for HBP was 51.3, with a sensitivity of 69.2% and a specificity of 89.5%. Conclusion: The study found that HBP levels are significantly associated with the occurrence of PJI following TJA, serving as an effective independent predictive factor for PJI risk. HBP has high predictive value and can be considered an important biomarker for predicting PJI post-TJA in clinical settings, aiding in the early identification and management of PJI, thereby improving patient treatment outcomes and quality of life.

C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) are valuable markers for detecting periprosthetic joint infection (PJI) post-total knee arthroplasty (TKA). However, their prolonged elevation after TKA diminishes diagnostic reliability. This study investigates CRP and ESR trends in unilateral (U-TKA) and simultaneous bilateral TKA (SB-TKA) patients, comparing their patterns.

Between 2017 and 2023, preoperative and postoperative (weeks 2, 4, 6) CRP and ESR levels were assessed in U-TKA (32 patients) and SB-TKA (29 patients) groups for gonarthrosis.

Median preoperative CRP levels were 1.13 mg/dL (U-TKA) and 0.2 mg/dL (SB-TKA), with corresponding ESR levels of 13.50 mm/h and 10 mm/h. While CRP and ESR increased more in SB-TKA, differences were statistically insignificant (p > 0.05). Both groups showed significant differences in CRP and ESR values at all time points (p < 0.05). U-TKA patients reached CRP < 5 mg/dL and ESR < 30 mm/h by the 6th postoperative week. SB-TKA patients did not exhibit significantly higher CRP and ESR levels at various intervals compared to U-TKA patients (p > 0.05).

This study delineates postoperative CRP and ESR trends in U-TKA and SB-TKA for osteoarthritis. CRP values decreased below 5 mg/dL, and ESR values below 30 mm/h within 6 weeks in both groups. Statistically significant differences in CRP and ESR values were observed at all time points. No significant differences were found in CRP and ESR trends between both groups. These findings aid physicians in interpreting laboratory reports for PJI determination.

III.

Despite the success of two-stage exchange total knee arthroplasties (TKAs), a subset of patients become reinfected and may be considered for a repeat two-stage exchange TKAs. A small, prior study from our institution demonstrated a 50% re-revision rate in such a cohort. The purpose of the present study was to evaluate a contemporary and larger cohort of repeat two-stage exchange TKAs with an emphasis on implant survivorship, risk factors, and clinical outcomes.

We retrospectively identified 87 repeat two-stage exchange TKAs performed between 2014 and 2021. The mean patient age was 66 years, 32% were women, and the mean body mass index was 29. At the time of resection, 98% of patients were treated with a high-dose antibiotic spacer (58 nonarticulating and 27 articulating). The mean time from resection arthroplasty to reimplantation was 22 weeks. Kaplan-Meier survivorship analyses were performed, and risk factors (including the McPherson staging system) were assessed. The mean follow-up was five years (range, two to nine).

The 5-year survivorships free of rerevision for reinfection, any rerevision, and any reoperation were 88, 67, and 54%, respectively. Leading causes for rerevision were periprosthetic joint infection (36%) and aseptic loosening (27%). There were no statistically significant independent risk factors identified. However, patients who had McPherson host grade C trended toward higher rates of reoperation (hazard ratio: 2, P = 0.057). Despite the high reoperation rate, at the final follow-up (mean five years), 91% of patients had a TKA in situ, 8% had been treated with above-knee amputation, and 1% with a definitive resection arthroplasty.

Despite its challenges, including a 54% reoperation rate, repeat two-stage exchange TKAs may be considered in a subset of patients given 91% of patients had a TKA in situ at a mean of five years, and the 5-year survivorship free of rerevision for infection was 88%. Notably, patients who were McPherson host grade C trended toward failure.

Level IV.

Periprosthetic joint infection leads to significant morbidity and mortality after total knee arthroplasty. Preoperative and perioperative risk prediction and assessment tools are lacking in Asia. This study developed the first machine learning model for individualized prediction of periprosthetic joint infection following primary total knee arthroplasty in this demographic.

A retrospective analysis was conducted on 3,483 primary total knee arthroplasty (81 with periprosthetic joint infection) from 1998 to 2021 in a Chinese tertiary and quaternary referral academic center. We gathered 60 features, encompassing patient demographics, operation-related variables, laboratory findings, and comorbidities. Six of them were selected after univariate and multivariate analysis. Five machine learning models were trained with stratified 10-fold cross-validation and assessed by discrimination and calibration analysis to determine the optimal predictive model.

The balanced random forest model demonstrated the best predictive capability with average metrics of 0.963 for the area under the receiver operating characteristic curve, 0.920 for balanced accuracy, 0.938 for sensitivity, and 0.902 for specificity. The significant risk factors identified were long operative time (OR, 9.07; p = 0.018), male gender (OR, 3.11; p < 0.001), ASA > 2 (OR, 1.68; p = 0.028), history of anemia (OR, 2.17; p = 0.023), and history of septic arthritis (OR, 4.35; p = 0.030). Spinal anesthesia emerged as a protective factor (OR, 0.55; p = 0.022).

Our study presented the first machine learning model in Asia to predict periprosthetic joint infection following primary total knee arthroplasty. We enhanced the model's usability by providing global and local interpretations. This tool provides preoperative and perioperative risk assessment for periprosthetic joint infection and opens the potential for better individualized optimization before total knee arthroplasty.

Wear particle-induced periprosthetic osteolysis is a prevalent issue that frequently leads to the failure of joint replacements, necessitating the development of effective therapeutic strategies. In this study, we established a mouse model of prosthetic loosening and evaluated the therapeutic effects of targeting tumor necrosis factor-alpha (TNF-α) and wingless-type MMTV integration site family, member 3A (Wnt3a) on osteolysis. TNF-α knockdown reduced inflammation and osteoclast-related gene expression, while Wnt3a overexpression increased osteoblast-related gene expression. Notably, the combination of these interventions showed superior efficacy in inhibiting osteolysis compared to monotherapy. Biomechanical imaging and histological staining revealed that combined therapy enhanced bone density and minimized the gaps between the peri-prosthetic bone and the prosthesis, reducing fibrous connective tissue proliferation. Adeno-associated virus-mediated gene therapy was found to be safe, with no adverse effects observed in liver, brain, spleen, and kidney tissues. Our findings suggest that combining TNF-α silencing with Wnt3a overexpression may be a promising approach for treating particle-induced peri-implant osteolysis and warrants further clinical investigation.

Up to 20% of primary total knee arthroplasty (TKA) patients are not satisfied with their outcome. Both the analysis of these patients and revision surgery can be complex, expensive and outcomes can vary widely.

The aim of this study was to deliver consensus recommendations regarding outpatient analysis, surgical treatment and arrangement of clinical services concerning patients with a problematic TKA or revision knee replacement (RTKA).

Members of BASK and EKS were invited to attend a joint meeting in London, UK (December 2019). A formal consensus process was undertaken at the meeting incorporating a multiple round Delphi exercise, with group discussion of areas of agreement and disagreement between rounds. Eighty delegates attended the meeting and five consensus statements were considered, with a threshold level of 80% agreement required as the definition consensus. A further consensus meeting of EKS members in Kitzbuhl, Austria (January 2023) followed similar methodology and considered a further four statements on this topic.

From the first meeting, 5 consensus statements with accompanying supporting evidence and text were agreed. 1) In suspected infection, a recognised diagnostic pathway and definition should be used (e.g. MSIS, ICM, EBJIS) and documented; 2) Revision of an infected TKA should be treated in units with a multidisciplinary team; 3) Initial investigation of a problematic TKA should include a minimum of: clinical investigation, X-Rays and blood tests, with further discussion with the MDT if required; 4) Units providing RTKA should have surgeons with evidence of specific training or experience, and on-going minimum unit numbers; 5) National Orthopaedic/Knee Societies should develop a strategy on Revision TKA provision taking into account: workforce, revision burden, location, hospital infrastructure. From the second meeting a further 4 consensus statements were agreed. Two statements were agreed text content answering the questions: 1) What should be included in the basic diagnostic workup of a painful TKA? and 2) Which are the key factors for surgeons to consider before offering the patient revision surgery? The two other agreed statements are: 3) Pre-operative diagnosis is related to outcome in RTKA and 4) RTKA for pain, without a surgically treatable diagnosis, is unpredictable.

The agreed joint BASK-EKS consensus statements and the EKS consensus statements on the assessment of problematic RTKA are recommended as the contemporary basis of optimal care for these patients and should inform future training and service developments.

Despite significant advancements in total knee arthroplasty (TKA), some patients require revision surgery (R-TKA) due to complications such as infection, mechanical loosening, instability, periprosthetic fractures, and persistent pain. This study aimed to explore the specific causes leading to R-TKA, associated complications, including infection, mechanical failure, and wound issues, as well as costs, mortality rates, and hospital length of stay (LOS) using data from a large national database.

Data from the nationwide inpatient sample (NIS), the largest publicly available all-payer inpatient care database in the United States were analysed from 1 January 2016 to 31 December 2019. The study included 44,649 R-TKA cases, corresponding to 223,240 patients, with exclusions for nonelective admissions. Various statistical analyses were used to assess clinical outcomes, including in-hospital mortality, postoperative complications, LOS, and hospitalization costs.

Among 2,636,880 TKA patients, 8.4% underwent R-TKA. R-TKA patients had higher rates of chronic conditions, including mental disorders (36.4%) and renal disease (9.9%). Additionally, these patients often experienced instability, necessitating revision surgery. Infection (22.3%) was the primary reason for R-TKA, followed by mechanical loosening (22.9%) and instability. Compared to primary TKA patients, R-TKA patients exhibited higher in-hospital mortality (0.085% vs. 0.025%), longer LOS (3.1 vs. 2.28 days), and higher total charges ($97,815 vs. $62,188). Postoperative complications, including blood transfusion (4.6% vs. 1.3%), acute kidney injury (4.4% vs. 1.8%), venous thromboembolism (0.55% vs. 0.29%), infection, and wound problems, were significantly higher in R-TKA patients.

This study provides detailed insights into t LOS, costs, and complications associated with specific etiologies of revision TKA. Our findings emphasize the need for targeted preoperative optimization and patient education. This approach can help reduce the incidence and burden of R-TKA, improve patient care, optimize resource allocation, and potentially decrease the overall rates of complications in revision surgeries.

Level III.

Background/Objectives: Periprosthetic joint infections (PJIs) are feared complications in arthroplasty and are associated with an increased mortality rate. PJI prevention is of paramount importance since treatment is difficult. In case of an infection, it is crucial to diagnose it at an early stage in order to initiate adequate therapy. The Musculoskeletal Infection Society (MSIS) proposed a catalog of different major and minor diagnostic criteria in 2011 to define a PJI. They were adapted in the following years. One of these criteria is the blood level of C-reactive protein (CRP). CRP is a non-specific acute-phase protein that also increases in response to various non-infectious inflammatory responses. CRP is also routinely obtained prior to total hip arthroplasty (THA) to screen for possible contraindications for arthroplasty such as an acute infection. The validity of this approach has rarely been investigated. The aim of this study was to evaluate the diagnostic value of perioperative CRP in patients receiving a THA. Methods: A total of 239 patients were included in this study and retrospectively analyzed. CRP values were obtained preoperatively and three values postoperatively. Sensitivity, specificity, area under the curve (AUC) and optimal thresholds were calculated. Results: In the whole group, 10 patients developed a PJI. No significance was demonstrated between patients without and with later PJI in terms of preoperative CRP (p = 0.182), postoperative CRP (p = 0.167), relative CRP increase (p = 0.684) and respective CRP differences (p = 0.456). We were not able to find cut-off values with adequate sensitivity and specificity. Conclusions: Perioperative CRP values do not seem to be helpful in predicting further PJI. Rather, they should be used as a screening tool to detect ongoing infections in the individual patient prior to THA. This trial should encourage studies with more statistical power due to the small effect sizes.

Short-keeled tibial implants may be at higher risk of aseptic loosening. Stem augmentation has been suggested to improve its fixation. We aimed to assess whether this technique could decrease the loosening rate of such tibial implants.

We retrospectively studied the knees receiving stemmed versus nonstemmed versions of a short-keeled prosthesis. A total of 932 patients undergoing total knee arthroplasty using a Persona prosthesis with >24-month follow-up (mean 53.7) were included, of whom 212 were at high risk of loosening due to osteoporosis or high body mass index (BMI). The rate of tibial aseptic loosening in high-risk patients and in the whole cohort was compared between those with and without stem extension. Multivariable analysis was conducted to identify the risk factors of loosening.

In the whole cohort, in 203 knees (21.8%), a cemented short stem was used, versus 729 knees (78.2%) without. The tibial implant revision rates for loosening were 2.06% and 0.99% for nonstemmed and stemmed cases, respectively ( P = 0.551). When the cohort was categorized based on the loosening risk factors, the loosening risk was significantly higher in the high-risk than in the low-risk group, regardless of stem status (log-rank test = 8.1, hazard ratio = 2.17, 95% CI = 1.78, 2.57, P = 0.005). 212 patients were at high risk of loosening, due to high BMI or osteoporosis, among whom the risk of aseptic loosening was higher when a stem was not used (log-rank = 32.1, hazard ratio = 4.95, 95% CI = 4.05, 5.86, P < 0.001). In multivariate analysis, osteoporosis, BMI ≥35, and smoking were correlated with loosening.

The failure rate was markedly lower in the stemmed group of the patients at elevated risk of aseptic loosening due to osteoporosis and/or high BMI. In the entire cohort, the risk of loosening in stemmed tibial implants was similar to the nonstemmed group. The findings support a protective role for the stem in patients at high risk of failure of the cemented tibial implant.

III therapeutic.

This prospective clinical cohort was undertaken to determine the long-term risks of reinfection and all-cause aseptic failure after 1-stage exchange total knee arthroplasties (TKA) in a large series of consecutive patients with periprosthetic joint infection (PJI) following TKA.

One-stage exchange for chronic PJI is an effective strategy, even in a non-selected population.

Non-selected patients (152 with 154 PJI) undergoing 1-stage-exchange TKA for PJI (January 2003-August 2015) were prospectively included and monitored for ≥2 years. PJI following TKA satisfying Musculoskeletal Infection Society diagnostic criteria were documented by microbiological culture results of preoperative joint aspirates and/or intraoperative samples. The cumulative incidences of total reinfections (i.e., relapses or new infections) and aseptic revisions were assessed. The mean follow-up (FU) duration was 7.5 years post-reimplantation.

At the last follow-up, 35 knees had developed reinfections: 7 relapses and 28 new infections, with respective 14-year cumulative incidences of 4.8% and 20.6%. The 2-, 5- and 14-year cumulative total reinfection incidences were 12.3%, 21.3% and 24.3%, respectively. Respective 2-, 5-, 10- and 14-year aseptic component-revision incidences were 0.7%, 3.2%, 5.4% and 13.4%. Multivariate analysis retained male sex (HR 3.27, p < 0.01) and preoperative atrial fibrillation (HR 3.03; p = 0.01) as being significantly associated with greater risk of reinfection.

One-stage-exchange TKA with aggressive debridement for chronic PJI is apparently a valid strategy, even for non-selected patients. It was associated with a low relapse rate, prevented morbidity and avoided economic social costs of 2-stage exchange. New infections with a different microorganism were observed more frequently and occurred even after years of FU.

II; Therapeutic.

Total knee arthroplasty (TKA) is a highly effective surgical intervention for alleviating pain and restoring function in patients with end-stage knee osteoarthritis. Walking ability, a critical measure of post-operative success, directly impacts patients' independence, mobility, and quality of life. This review comprehensively examines the factors influencing walking ability after TKA, encompassing pre-operative, surgical, and post-operative considerations. Pre-operative factors, such as patient demographics, functional status, psychological well-being, and comorbidities, significantly shape post-operative outcomes. Surgical techniques, including the choice of approach, implant design, alignment, and minimally invasive or robotic-assisted methods, also play a pivotal role in determining walking ability. Post-operative rehabilitation, particularly early mobilization, physical therapy, and exercise protocol adherence, is essential for optimizing recovery. Long-term outcomes reveal that, while most patients experience significant improvements in walking ability, some face persistent limitations due to age, comorbidities, or suboptimal surgical results. Emerging technologies, such as wearable devices, robotic-assisted surgery, and personalized rehabilitation programs, offer promising avenues for enhancing post-operative walking ability. Biological augmentation techniques, like platelet-rich plasma and stem cell therapy, are also being explored to improve tissue healing and functional recovery. This review underscores the importance of a multidisciplinary, patient-centered approach to maximize walking ability and overall satisfaction after TKA, synthesizing evidence from clinical studies, meta-analyses, and systematic reviews. Future research should focus on refining surgical techniques, advancing rehabilitation strategies, and integrating personalized medicine to improve outcomes.

Periprosthetic joint infections (PJIs) following total knee arthroplasty (TKA) are associated with high patient morbidity, mortality, and health care costs. Methods to reduce the burden of PJI have been shown to be efficacious on a small scale. On a national scale, it is unknown whether these methods have reduced PJI rates.

A retrospective trend analysis was conducted using a national database. The incidence of 2-year septic revision was observed for the entire cohort in patients who had high-risk comorbidities from 2010 to 2019. A multivariable logistic regression was performed to compare the odds ratios of 2-year septic revision rates from 2011 to 2019 to the reference year of 2010. Linear regression was used to compare the change in the overall and high-risk subanalysis groups.

Among the 860,185 patients, 5,589 underwent septic revision within 2 years. The 2-year septic revision rate decreased from 0.75% in 2010 to 0.69% in 2019 (compounded annual growth rate = -0.94%, P = 0.049). Multivariable logistic regressions demonstrated that the odds of septic revision in 2019 were significantly lower than those in 2010 (odds ratio: 0.83, 95% CI [confidence interval]: [0.70 to 0.96], P = 0.017). In high-risk patients, the septic revision rate decreased from 1.04 to 0.80% (compounded annual growth rate = -2.80%, P = 0.004), specifically in those who had a history of psychoses, Medicaid insurance, anemia, heart failure, obesity, liver disease, tobacco use, and drug abuse (P < 0.05 for all).

This study demonstrated a national reduction in the 2-year septic revision rate in all TKA patients, including patients considered at high risk for PJI. This suggests that current preventative methods may be efficacious on a national scale in TKA. Further research is needed to identify more modalities to reduce the national incidence of this morbid and costly complication.

Implants aim to restore skeletal dysfunction associated with ageing and trauma, yet infection and ineffective immune responses can lead to failure. This project characterized the microbiological and host cell responses to titanium alloy with or without electroplated metallic copper. Bacterial viability counting and scanning electron microscopy quantified and visualized the direct and indirect bactericidal effects of the Cu-electroplated titanium (Cu-Ep-Ti) against two different Staphylococcus aureus strains. Human THP-1 macrophage adhesion and viability was analyzed, along with phagocytosis. Results showed potent antimicrobial activity alongside promising host-immunomodulatory properties. Direct and indirect exposure to Cu-Ep-Ti produced potent bactericidal effects resulting in 94-100% reductions in bacterial viability at 24 h, with complete eradication in some cases. As expected, cytotoxicity was observed in THP-1 macrophages without media exchange, though when media was exchanged at 8, 24 and 48 h cell viability was equivalent to Control-Ti. Interestingly macrophages adhered to the copper material or grown in the presence of copper ions showed 7-fold increase in phagocytosis of S. aureus bioparticles compared to Control-Ti, suggesting a dual bactericidal and host immunomodulatory mechanism. In conclusion, this Cu-electroplated Ti biomaterial can limit bacterial contamination on the implant surface, whilst simultaneously promoting a beneficial antimicrobial immune response.

Revision total knee arthroplasty (rTKA) is a complex procedure that often requires the removal of previous implants. There is little information evaluating the difference between removing cemented or noncemented knee prostheses in revision surgeries. The purpose of this study was to determine whether removing cemented or noncemented implants would affect surgical time and expenses incurred during revision procedures.

This retrospective cohort study used a single-institution database to identify 300 patients who underwent femoral and tibial implant rTKA from 2016 to 2022 because of mechanical complications (infection cases excluded). Radiographs and surgical reports were used to confirm whether the fixation technique was cemented (N = 243) or noncemented (N = 57). The primary outcomes were surgical time and surgery costs. Secondary outcomes included readmission rates, revision implants used, stem usage, and insurance type.

The average surgical time was 121 minutes for noncemented and 128 minutes for cemented procedures ( P = 0.118). The 90-day readmission rates for each group were similar at 7.00% for the cemented cohort and 8.77% for the noncemented cohort ( P = 0.643). For patients with Medicare Advantage, the respective surgery costs were $1,966 for noncemented and $1,968 for cemented TKA ( P = 0.988). For patients with commercial insurance, the respective surgery costs were $4,854 for noncemented and $5,660 for cemented TKA ( P = 0.330).

Primary knee fixation type, cemented or noncemented, did not appear to influence the surgical duration or surgical costs of both-implant revision knee surgery indicated for mechanical complications.

Previous studies identified corrosion between the modular tibial components of total knee arthroplasty devices. However, gaps persist. Compared to the hip, damage modes that occur within taper junctions in the knee remain poorly understood. In this study, we investigated corrosion on total knee arthroplasty components with titanium-titanium junctions. We asked the following question: under typical in vivo cyclic loading conditions, will the same alloy damage modes from total knee arthroplasty devices resemble those documented in the hip?

A total of 50 paired titanium alloy tibial baseplates and stems were collected and semiquantitatively analyzed using Goldberg corrosion scoring. To characterize damage, a subsection of moderately and severely corroded components was sectioned and imaged using scanning electron and digital optical microscopy.

Of the 100 device components, 95% showed visual evidence of corrosion. The initial contact area between the stem and bore generally occurred 3 mm from the stem taper base. Scanning electron microscopy revealed 4 damage modes, including oxide film formation, crevice corrosion, selective dissolution, and pitting.

Each of the damage modes identified in modular titanium-titanium tibial junctions was previously reported by total hip arthroplasty retrieval studies. Cumulatively, our results suggest that mechanically assisted crevice corrosion promoted this damage in vivo.

Anemia and blood transfusions are recognized as risk factors for periprosthetic joint infections (PJI). Tranexamic acid (TXA) is established in reducing perioperative blood loss and transfusion requirements. Our study investigates the impact of perioperative TXA administration on the incidence of PJI in patients undergoing total joint arthroplasty (TJA) and evaluates the association of intravenous (IV) and topical applications with PJI occurrence.

A retrospective review was performed on 8042 patients who underwent primary total hip arthroplasty (THA) and knee arthroplasty (TKA) from January 2009 to December 2020, with a minimum one-year follow-up at our institution. We compared patients who received TXA (n = 3664, with 2345 receiving it IV and 1319 topically) to those who did not (n = 4378). 0.5-1.25 g of IV TXA was administered before skin incision, and 1.5-3 g of topical TXA was injected intra-articularly or into the drainage tube during surgery. The primary outcome was PJI development within one year, defined by the 2013 International Consensus Meeting criteria. Secondary outcomes included blood transfusion, hospital length of stay (LOS), venous thromboembolism (VTE), and 90-day readmission. We employed multivariate logistic regression and propensity score weighting to adjust for potential confounders and conducted subgroup analyses to assess PJI odds in TKA and THA patients treated with IV and topical TXA.

The TXA group demonstrated a lower PJI occurrence (1.1% vs. 2.1%, p < 0.001), less blood transfusion (14.4% vs. 22.7%, p < 0.001) and shorter LOS (5.6 ± 1.6 vs. 6.5 ± 2.5, p < 0.001) compared to those without TXA. There was no difference between the two groups with regards to VTE and 90-day readmission. Perioperative TXA administration demonstrated lower PJI in multivariate analysis (OR 0.54, 95% CI 0.36-0.80, p = 0.002), and in propensity score weighting (OR 0.53, 95% CI 0.36-0.80, p = 0.002). In the subgroup analysis, both IV and topical administration of TXA resulted in decreased PJI (IV group: OR 0.53, 95% CI, 0.33-0.84, p = 0.007, topical group: OR 0.51, 95% CI, 0.29-0.89, p = 0.018), especially in primary TKA (IV TXA, OR 0.49, 95% CI, 0.29-0.83, p = 0.008; Topical TXA, OR, 0.56, 95% CI, 0.32-0.98, p = 0.042).

Perioperative TXA administration in primary hip and knee arthroplasty is significantly associated with a reduced PJI occurrence. Both IV and topical TXA routes showed similar association with reduced PJI occurrence, with a notable correlation observed in primary TKA.

Periprosthetic joint infection (PJI) is a serious complication following primary total joint arthroplasty (TJA). PJI accounts for 15-25% of revision surgeries, therefore it is associated with PJI is associated with substantial patient morbidity and mortality as well as increased healthcare expenditures due to complex treatment strategies. Recently, intraoperative local application of vancomycin powder is increasingly being used in primary total hip and knee arthroplasty (THA, TKA) as an additive strategy for PJI prevention. Whereas local vancomycin concentrations have already been investigated in prior studies, evidence on systemic vancomycin levels and potential adverse drug reactions (ADR) is limited. Purpose of this study was to investigate systemic vancomycin levels following intraarticular application in primary TJA.

This pilot study is a prospective analysis of patients undergoing primary THA and TKA between April and July 2023. One gram of vancomycin powder was applied to the prosthesis prior to wound closure. Serum vancomycin levels were measured at two standardised time points, 24 and 48 h postoperatively.

In total, 103 patients were included, and the patient collective was further stratified by surgical procedure into a THA subgroup (n = 52) and a TKA subgroup (n = 51). Mean serum vancomycin levels showed a significant group difference at both time points (24 h: p < 0.001; 48 h: p = 0.044) with higher serum vancomycin concentrations in the THA cohort. Mean serum vancomycin levels in THA patients were 1.25 μg/ml (range 0.00-7.00 μg/ml) after 24 h and 0.34 μg/ml (range 0.00-4.80 μg/ml) 48 h postoperatively. In TKA, no systemic vancomycin levels were detected. Vancomycin concentrations did not reach therapeutic levels in any patient. No ADR was detected in the whole study collective.

Following intraarticular administration of vancomycin powder, no systemic vancomycin levels within the therapeutic range were detected, thus it may serve as a safe and cost-effective adjunct to strategies for prevention of PJI.

Background: Outcomes following total knee arthroplasty (TKA) revisions are variable, and it is hypothesized that the underlying cause of primary TKA failure impacts postoperative outcomes. This study analyzes the results of TKA revisions seven years after surgery, in relation to the etiology of primary failure and other influencing factors. A previous study conducted in 2013 examined the same cohort of patients three months after revision surgery. Methods: From the original study, 97 patients were followed up, and 49 patients were eligible for inclusion. Patients were classified into four groups: "periprosthetic infection" (PPI), "aseptic loosening," "instability," and "arthrofibrosis." Outcomes were analyzed using established scores (the Knee Society Score (KSS), New Knee Society Score (nKSS), and the Western Ontario and McMaster Universities (WOMAC) index) and considering factors such as age, gender, BMI, and ASA classification. The outcomes were analyzed using three time intervals: "Outcome Short" (preoperative to 3 months postoperative); "Outcome Long" (preoperative to 7 years postoperative); and "Delta PostOP" (3 months postoperative to 7 years postoperative). Results: Significant improvements were observed in all time intervals, especially in the "Outcome Short" (p < 0.001) and "Delta PostOP" (p < 0.001) periods. The "instability" and "aseptic loosening" groups showed better outcomes in terms of range of motion and knee scores than the "arthrofibrosis" and "infection" groups (p < 0.05). A lower BMI and an ASA status of II were associated with better outcomes (p < 0.05). Women also showed superior results in the nKSS (p < 0.05). Discussion: Patients with "aseptic loosening" and "instability" had the best long-term outcomes. Lower BMI and better ASA status also correlated with improved results. These findings can inform patients of the potential outcomes of revision surgery, thereby facilitating informed decision-making.

Periprosthetic joint infection (PJI) is a complication that occurs in less than 1% of patients after unicompartmental knee arthroplasty (UKA). Though infrequent, it may potentially lead to revision while placing a significant financial burden on the healthcare system. Preoperative, intra-operative, and postoperative strategies should be implemented to minimize the risk of PJI. Patient optimization prior to surgery can help to identify patients at risk for PJI and also maximize the health of the patient prior to surgery. Intraoperative and postoperative strategies can also mitigate the risk of postoperative infection. This article will summarize the evidence for preoperative, intra-operative, and postoperative strategies to prevent PJI in UKA. This will include topics on malnutrition and obesity, Staphylococcus aureus, smoking, human immunodeficiency virus, rheumatoid arthritis, as well as skin preparation, laminar air flow, preoperative antibiotic administration antimicrobial incision drapes, pulsatile lavage, vancomycin powder, wound closure method, thromboprophylactic agents, and closed incisional negative pressure wound therapy dressings.

The increasing frequency of total hip (THA) and knee arthroplasties (TKA) is marred by the rise in periprosthetic joint infections (PJIs) and surgical site infections (SSIs), with PJIs incurring costs over $1.62 billion as of 2020 and individual case management averaging $90,000. SSIs additionally burden the U.S. healthcare economy with billions in expenses annually. PJI prevalence in primary THA and TKA ranges from 0.5% to 2.4%, spiking to 20% in revisions and representing 25% of TKA revision causes. Projections estimate up to 270,000 annual PJI cases by 2030. Often caused by gram-positive bacteria, particularly methicillin-resistant staphylococci, these infections demand preventive measures. This review dissects PJI prevention across preoperative, intraoperative, and perioperative phases, aligning with evidence-based CDC and WHO guidelines. Preoperative measures include managing diabetes, obesity, tobacco use, Staphylococcus aureus screening and nasal decolonization, nutritional optimization, and management of inflammatory arthropathies. Intraoperatively, antibiotic prophylaxis, skin preparation, operative room environmental controls, surgical technique precision, and irrigation options are scrutinized. Perioperative concerns focus on anticoagulation, blood management, and infection risk mitigation. Integrating these strategies promotes a patient-centric care model, aiming to reduce PJI incidence, improve patient outcomes, and increase care cost-effectiveness in joint arthroplasty.

To confirm the diagnosis of periprosthetic joint infection (PJI), the Infectious Diseases Society of America (IDSA) and the International Consensus Meeting (ICM) have defined criteria that include histology as a minor criterion and the sonication method only as an additional criterion. The aim of this monocentric, retrospective study was to investigate the value of histology and whether sonication leads to a more accurate diagnosis.

All revision surgeries for knee and hip arthroplasty between 2017 and 2020 were included. With regard to microbiological diagnostic, conventional culture of periprosthetic biopsies and sonication of explant material were performed. In addition, histology and non-specific inflammatory markers (CRP, leukocytes) were recorded.

A total of 78 patients with PJI and 62 aseptic controls were included. From both microbiological methods (conventional culture / sonication), Staphyloccus (S.) epidermidis and S. aureus were detected most frequently. However, compared to the conventional microbiology, a higher sensitivity was calculated for sonication, albeit with a lower specificity in relation to a PJI. In two logistic regression models for the significance of all diagnostic parameters in PJI, the AUC was 0.92 and 0.96 with histology in particular making the decisive contribution in both models (p < 0. 001, both models).

Since histology showed the highest accuracy in the current study, its importance in the PJI criteria should be reevaluated. Sonication shows a high sensitivity for germ detection with a lower specificity and should only be used in combination with the conventional culture for microbiolgical diagnostics.

After clinical introduction in 2005, sequentially annealed, highly cross-linked polyethylene (SA HXLPE) was studied for retrievals with short implantation times; however, long-term follow-ups are lacking. The objective of this study was to examine and compare the revision reasons, damage mechanisms, and oxidation indices of SA HXLPE and conventional gamma inert-sterilized (Gamma Inert) ultra-high-molecular-weight polyethylene tibial inserts implanted for >5 years.

There were 74 total knee arthroplasty tibial inserts (46 SA HXLPEs, 28 Gamma Inerts) implanted for >5 years (mean 7 ± 2 years) retrieved as part of a multicenter retrieval program. Cruciate-retaining implants comprised 44% of the SA HXLPEs and 14% of the Gamma Inerts. Patient factors and revision reasons were collected from revision operating notes. A semiquantitative scoring method was used to assess surface damage mechanisms. Oxidation was measured using Fourier transform infrared microscopy according to American Society for Testing and Materials 2102. Differences between cohorts were assessed with Mann-Whitney U-tests.

Loosening (Gamma Inert: 17 of 28, SA HXLPE: 15 of 46) and instability (Gamma Inert: 6 of 28, SA HXLPE: 15 of 46) were the most common revision reasons for both cohorts. The most prevalent surface damage mechanisms were burnishing, pitting, and scratching, with burnishing of the condyles being higher in Gamma Inert components (P = .022). Mean oxidation was higher in the SA HXLPE inserts at the articulating surface (P = .002) and anterior-posterior faces (P = .023). No difference was observed at the backside surface (P = .060).

Revision reasons and surface damage mechanisms were comparable in the Gamma Inert and SA cohorts. Further studies are needed to continue to assess the in vivo damage and clinical relevance, if any, of oxidation in SA HXLPE over longer implantation times, particularly for implants implanted for more than 10 years.

The accurate and timely diagnosis of periprosthetic joint infection (PJI) is critical for guiding optimal treatment management and success, highlighting the requirement of readily available inexpensive serum biomarkers to increase the diagnostic accuracy for PJI. Many studies have investigated the diagnostic accuracy of neutrophil to lymphocyte ratio (NLR) and monocyte to lymphocyte ratio (MLR). However, there is a lack of existing literature regarding optimal thresholds for acute PJI. The purpose of this study was to reveal the most appropriate cut-off values for MLR and NLR in detecting acute PJI with a gender specific analysis.

Patients were classified as having an acute PJI if they met the International Consensus Meeting (ICM) 2018 modified criteria. Patients who had a negative clinical and diagnostic workup for a PJI and the presence of erythema on the index surgical area were included in the erysipelas group (control group). Data obtained from all patients included age, sex, body mass index (BMI), Charlson Comorbidity Index (CCI), procedure type (THA or TKA), serum C-reactive protein (CRP), and blood studies at the admission and culture results were retrieved from the electronic medical record.

ROC curve analysis was used to determine the gender-specific optimal threshold values for CRP, NLR, and MLR. Comparing the sensitivities and specificities of NLR and MLR at the identified best thresholds in males and females, the study found similar sensitivities of NLR in males and females with 0.84 and 0.84, respectively. On the other hand, an MLR of 0.67 or more reported a notably higher specificity in male patients [0.90 (95% CI 0.75-0.96) versus 0.70 (95% CI 0.56-0.80)].

NLR and MLR represent commonly ordered, low-cost, simple, and readily available complete cell count laboratory values and should be used as adjunct tests with reasonable diagnostic accuracy in detecting acute PJIs. Moreover, with its excellent specificity and PPV, MLR could provide valuable insight in diagnosing acute PJI, particularly in male patients.

Level III Retrospective Cohort analysis.

As the volume of primary total knee arthroplasty (TKA) continues to grow, the clinical and financial burden of revision total knee arthroplasty (rTKA) is expected to increase. The purpose of this investigation was to characterize contemporary indications and complications for rTKA.

Patients undergoing rTKA between 2010 and 2021 were identified within an administrative claims database. Adjusted rTKA incidence was calculated by dividing the annual rTKA volume by the annual primary TKA and multiplying by 100,000. Mann-Kendall trend tests were utilized to trend revision volume, etiology, 90-day postoperative complications, and patient demographics.

A total of 397,367 rTKA were identified over our study period, of which 287,492 (72.4%) had coding regarding revision etiology. The volume of annual rTKA (31,091 to 33,850; P = 0.451) did not change over the study period. The adjusted incidence of rTKA decreased (25,568.3 to 19,272.2 per 100,000 annual TKA; P = 0.011). The leading causes of revision TKA were infection (21.2%), aseptic implant loosening (19.3%), and instability (9.8%). The rate of septic revision (4,710.5 to 4,426.1 per 100,000 annual TKAs) and aseptic implant loosening (4,502.5 to 3,636.4 per 100,000 annual TKAs) did not change (both P values > 0.05). The rates of instability increased (1,369.2 to 2,609.85 per 100,000 annual TKAs; P = 0.007). The rates of postrevision surgical site infection, periprosthetic joint infection, deep vein thrombosis, and transfusion decreased over the study period, while rates of emergency department visits and readmission increased (all P values <0.05).

The incidence of revision TKA may be slowing. While the risk of revision for infection and aseptic loosening remains unchanged, revision for instability has increased. The rates of postoperative complications appear to have decreased. Improved surgical technique, implant design, and perioperative protocols may have contributed to these findings. Continued work is necessary to reduce the risk of failure and postoperative complications.

Periprosthetic joint infections (PJIs) following total knee arthroplasty (TKA) are among the most challenging pathologies to manage. Recently, continuous local antibiotic perfusion (CLAP) therapy has been introduced for treating musculoskeletal infections in orthopedics. This study aimed to determine the outcomes and risks of CLAP therapy combined with conventional treatment for PJIs after TKA.

We retrospectively evaluated 14 patients with PJIs. For acute PJIs, CLAP therapy was performed alongside debridement, intravenous antibiotics, and implant retention. For chronic PJIs, a two-stage revision with CLAP therapy and intravenous antibiotics was performed. Implants were replaced with a cement mold incorporating CLAP therapy, followed by revision surgery after 3 months. For all patients, 120 mg/day of gentamicin (GM) was locally administered into the knee joint for 2 weeks as part of CLAP therapy, in combination with perioperative intravenous antibiotics.

Five patients developed acute PJIs, and nine developed chronic PJIs after TKA. The mean follow-up period was 18.4 (15.2-21.1) months. All five patients with PJIs treated with one-stage surgery (debridement and insert exchange only) successfully preserved their implants. Among the nine patients with chronic PJIs, seven underwent CLAP therapy combined with two-stage revision surgery, resulting in successful treatment without relapse, whereas the remaining two patients were initially treated with one-stage surgery and CLAP therapy but failed to retain their implants, and subsequently required additional two-stage revision surgery, which ultimately succeeded. No adverse effects from GM were reported.

Our results suggest that CLAP therapy is safe and may be effective for treating acute and most chronic PJIs after TKA.

Diagnosing periprosthetic joint infection (PJI) remains a significant challenge for healthcare professionals. Commonly utilized inflammatory markers include erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and white blood cells (WBC). Human β-defensin 1 (β-defensin) is an antimicrobial peptide elevated in infection, yet its diagnostic value for PJI has not been explored. The purpose of this study was to evaluate the efficacy of synovial β-defensin as a diagnostic marker for PJI and to compare its performance with ESR, serum CRP, and WBC.

We conducted a single-center retrospective study from October 2022 to June 2023. A total of 105 joint fluid samples from revision patients at the Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra were collected intraoperatively (71 hips, 34 knees) and frozen. According to MSIS criteria, 64 patients were defined as positive for PJI and the remaining 41 were negative. Synovial β-defensin levels were quantified using ELISA, serum CRP levels by immunoturbidimetry, and blood ESR and WBC were analyzed. Sensitivity and specificity were determined using ROC curves, and diagnostic performance was compared using the area under the curve (AUC). Cut-off values for diagnosing PJI were established.

Levels of synovial β-defensin, ESR, serum CRP, and WBC were significantly higher in the PJI group compared to the non-PJI (P < 0.0001). The AUCs were 0.948 for β-defensin, 0.884 for ESR, 0.902 for CRP, and 0.767 for WBC, with a combined AUC of 0.994. Sensitivity/specificity for β-defensin, ESR, CRP, and WBC were 0.966/0.830, 0.887/0.791, 0.930/0.771, and 0.820/0.682, respectively. Optimal predictive cut-off values were 1105.8 pg/mL for β-defensin, 11.5 mm/h for ESR, 5.55 mg/L for CRP, and 7.3 × 103/mm3 for WBC.

The synovial β-defensin assay demonstrated greater sensitivity and specificity for the diagnosis of PJI compared to ESR, serum CRP and WBC. Therefore, β-defensin shows promise as a diagnostic marker for PJI. Simultaneous determination of all markers may increase diagnostic confidence.

Despite significant progress in orthopaedic surgery, the prevalence of periprosthetic joint infections (PJIs) remains persistent, and future increases are expected due to the increasing number of joint arthroplasties. PJIs are intricately connected to biofilm-producing bacteria, which encase infected prostheses, impairing the effectiveness of antibiotics and the immune system. Acute PJIs with immature biofilms are traditionally managed with debridement, antibiotics, and implant retention (DAIR). However, to date, there has not been a conclusive direct clinical comparison (in vivo) demonstrating the superiority of one irrigation solution over others. Recently, there has been a growing interest in irrigation solutions with antibiofilm properties demonstrated in in vitro studies, exemplified by the preformulated Bactisure® irrigation solution, which contains ethanol, acetic acid, sodium acetate, benzalkonium chloride, and sterile water. The main objective of this study was to evaluate the effectiveness (infection cure rate) of preformulated Bactisure® irrigation solution in vivo compared with saline solution in a control group of patients with acute knee and/or hip periprosthetic infections treated with DAIR.

Prospective single-centre randomized controlled trial involving patients with acute haematogenous PJI who received standard DAIR surgery from December 2022 to December 2024. The type of irrigation solution used during surgery will include two groups allocated at a 1:1 ratio: a control group (n = 25) with saline solution and an experimental group (n = 25) receiving the Bactisure® preformulated solution. The sample size was calculated based on an expected reduction in reinfection rates from 45% in the control group to 10% in the experimental group. Data on baseline patient characteristics, clinical and radiological information, and healthcare questionnaires will be recorded. All patients will be followed for minimum of 12 months. The infection cure rate at 1 year will be the primary outcome.

This study is the first to compare the effectiveness of preformulated Bactisure® irrigation solution with that of saline solution in real clinical practice (in vivo) in patients with acute knee and/or hip periprosthetic infections treated with DAIR. Our main hypothesis is that, compared with saline solution, Bactisure® provides a better infection cure rate at 1 year post-DAIR.

International Standard Randomized Controlled Trial Number (ISRCTN): https://doi.org/10.1186/ISRCTN10873696 . Registered on December 19, 2023.

Polysulfone (PSF) medical waste can be effectively repurposed due to its excellent mechanical properties. Due to the increasing need for load-bearing bone implants, it is crucial to prioritize the development of biocompatible polymer-matrix composites. Calcium silicate (CaSi), known for its osteogenesis and antibacterial properties, is widely used in medical applications. In this study, recycled PSF plastics in fiber or nanoparticle forms and commercial PSF products were used to create PSF-based composites filled with three different amounts (10, 20, and 30 vol%) of CaSi. The green compact was heat-treated at various temperatures. Experimental results showed that the mechanical interlocking of the PSF matrix and CaSi filler occurred due to the liquefaction of PSF fibers or nanoparticles during heat treatment. When the composite contained 20% CaSi, the obtained three-point bending strength exceeded 60 MPa, falling within the reported strength of compact bone. There was a concurrent improvement in the biocompatibility and antibacterial activity of the PSF-based composites with the increasing amount of CaSi. Considering their mechanical properties and antibacterial activity, the 20% CaSi-containing PSF-based composites treated at 240 °C emerged as a promising candidate for bone implant applications. This study demonstrated the feasibility of upcycling medical waste such as PSF as a matrix, opening doors for its potential usage in the medical field.

Hip arthroscopy has gained popularity among orthopaedic procedures over the last decade. The present study aims to evaluate the trends of hip arthroscopy procedures in Italy analysing data recorded by the Italian Ministry of Health, reporting demographics, length of hospitalisation (LOS), diagnosis and the economic impact of the procedure.

The National Hospital Discharge records reported by the Italian Ministry of Health were used, analysing the data regarding hip arthroscopy procedures performed in Italy between 2001 and 2016. A total of 4022 hip arthroscopies were performed in Italy in the adult population.

The present study shows more males being exposed to the procedure, while the mean age of females was always higher than that of males during the 16-year study period. The mean LOS was 2.6 ± 3.2 days, and every procedure had a mean Italian hospital reimbursement from 1361€ to 1512€. Hip arthroscopy procedures have increased substantially between the years 2001 and 2016, as well as the costs related to the surgery.

The findings of this study constitute valuable clinical and scientific evidence for the healthcare system, which is useful not only for the formulation and improvement of national healthcare policies but also to improve awareness and accessibility of hip arthroscopy.

Level II.

Objective  To identify the causes of revision of total knee arthroplasty in a referral center in Brazil. Methods  This is a case series, with 80 patients undergoing revision surgery for total knee arthroplasty (RTKA) at a referral center for knee surgery, between August 2019 and November 2021, with a mean age of 69.6 years. Of these patients, 60.23% were female and 39.77% were male. The average body mass index (BMI) was 30.23 kg/m 2 . The causes of TKA failure were defined as: periprosthetic infection according to the 2018 International Consensus Meeting criteria, ligament instability, range of motion limitation, periprosthetic fracture, malalignment, aseptic loosening, pain due to non-replacement of the patellar cartilage, polyethylene wear, fracture of implants, insufficiency of the extensor mechanism. Results  Periprosthetic joint infection (PJI) was the main cause of revision total knee arthroplasty (TKA), corresponding to 47.73% of cases. Aseptic loosening of one or more components represented the second most frequent reason for TKA failure, accounting for 35.23% of revisions. Range of motion limitation represented the third most frequent cause, accounting for 5.68% of surgeries. Instability was the fourth most frequent reason for RTKA, occurring in 4.55% of patients. The other causes of revision were: periprosthetic fracture (3.41%), failure due to rupture of the extensor mechanism (2.27%), and pain attributed to non-replacement of the patellar cartilage (1.14%). Conclusions  Periprosthetic joint infection was the most frequent cause of TKA revision in our series. Other reasons for TKA failures were, in descending order: aseptic loosening, limited range of motion, and instability.

The purpose of this paper is to define a subset of complex rTKA in terms of preoperative, intraoperative, and postoperative outcomes and complications. The secondary outcome of the authors is to propose a simple and easy-to-use guide for clinical network in rTKA management.

Complex rTKAs were defined according to the presence of at least two of the following features: periprosthetic joint infection, re- revision, femoral and/or tibial massive bone defects, soft tissue impairment, stiffness, fracture requiring fixed component revision.

Twenty-six patients underwent a standard rTKA (group A) while 24 had a complex rTKA (group B). The mean follow-up was 50.2 ± 16.4 months in group A and 49.5 ± 16.8 in group B (p = 0.44). The operative time was longer in group B (200.4 ± 131.4 min vs 110.2 ± 59.8 min). A greater intraoperative total blood loss (3014.2 ± 740.0 vs 2328.5 ± 620.6 ml, p < 0.001), intra and postoperative blood infusion (3.6 ± 1.2 vs 2.1 ± 1.2 units, p < 0.001) was reported in group B. Significant difference was obtained for global complication rate (11.5% group A vs 37.5% group B, p = 0.04), reoperation (7.7% group A vs 33.3% group B, p = p = 0.03) and re-revision (3.8% group A vs 25% group B, p = p = 0.04).

This study describes a specific entity of rTKA that require higher surgical effort and increased surgical challenge (measured as increased surgical time, need of transfusions and complications). The proposed classification could provide an easy-to-use tool for quick grading of complexity in rTKA.

Periprosthetic joint infection (PJI) is a challenging complication of any arthroplasty procedure. We reviewed our use of static antibiotic-loaded cement spacers (ABLCSs) for staged management of PJI where segmental bone loss, ligamentous instability, or soft-tissue defects necessitate a static construct. We reviewed factors contributing to their failure and techniques to avoid these complications when using ABLCSs in this context.

A retrospective analysis was conducted of 94 patients undergoing first-stage revision of an infected knee prosthesis between September 2007 and January 2020 at a single institution. Radiographs and clinical records were used to assess and classify the incidence and causes of static spacer failure. Of the 94 cases, there were 19 primary total knee arthroplasties (TKAs), ten revision TKAs (varus-valgus constraint), 20 hinged TKAs, one arthrodesis (nail), one failed spacer (performed elsewhere), 21 distal femoral endoprosthetic arthroplasties, and 22 proximal tibial arthroplasties.

A total of 35/94 patients (37.2%) had spacer-related complications, of which 26/35 complications (74.3%) were because of mechanical failure of the spacer construct, while 9/35 (25.7%) were due to recurrence of infection. Risk factors for internal failure were a construct where the total intramedullary spacer length was less than twice the length of the central osseous defect (p = 0.009), where proximal or distal intraosseous spacer contact was < 10%, and after tibial tubercle osteotomy (p = 0.005). The incidence of spacer complications significantly increased the time to second stage: mean 157 days (42 to 458) in those without complications versus 227 days (11 to 528) with complications (p = 0.014).

The failure rate of static antibiotic-loaded cement spacers is much higher than anticipated. Complications of the spacer significantly increased the time to second-stage revision. The risk of mechanical failure is significantly increased if the spacer is less than double the size of the segmental defect, or if inadequate reinforcement is inserted into the residual bone. These findings serve as a guide for surgeons to avoid mechanical complications with static spacers.

Background: White blood cell (WBC) scintigraphy plays a major role in the diagnostic approach to periprosthetic infections. Although the procedure has been standardized by the publication of several guidelines, the interpretation of this technique may be susceptible to intra and inter-variability. We aimed to assess the reproducibility of interpretation between nuclear medicine physicians and by the same physician and to demonstrate that Cohen's coefficient is more unstable than Gwet's coefficient, as the latter is influenced by the prevalence rates. Methods: We enrolled 59 patients who performed a Technetium-99m WBC (99mTc-WBC) scintigraphy for suspected hip or knee prosthesis infection. Three physicians, blinded to all patient clinical data, performed two image readings. Each WBC study was assessed both visually and semi-quantitatively according to the guidelines of the European Association of Nuclear Medicine (EANM). For semi-quantitative analysis, readers drew an irregular Region of Interest (ROI) over the suspected infectious lesion and copied it to the normal contralateral bone. The mean counts per ROI were used to calculate lesion-to-reference tissue (LR) ratios for both late and delayed images. An increase in LR over time (LRlate> LRdelayed) of more than 20% was considered indicative of infection. Agreement between readers and between readings was assessed by the first-order agreement coefficient (Gwet's AC1). Reading time for each scan was compared between the three readers in both the first and the second reading, using the Generalized Linear Mixed Model. Results: An excellent agreement was found among all three readers: 0.90 for the first reading and 0.94 for the second reading. Both inter- and intra-variability showed values ≥0.86. Gwet's method demonstrated greater robustness than the Cohen coefficient when assessing the intra and inter-rater variability, since it is not influenced by the prevalence rate. Conclusions: These studies can contribute to improving the reliability of nuclear medicine imaging techniques and to evaluating the effectiveness of trainee preparation.