Background/Aims: Krebs von den Lungen-6 (KL-6) is associated with prognosis in patients with COVID-19. However, there is limited data on the correlation between the prognosis of COVID-19 and varying KL-6 levels at different time points. We investigated the optimal cutoff values of the initial and peak serum KL-6 levels to predict mortality and evaluated their correlation with mortality. Methods: This retrospective cohort study collected data on serially collected serum KL-6 levels in patients hospitalized with COVID-19 between October 2020 and January 2022 at a single tertiary hospital in South Korea. The area under the receiver operating characteristic curve and Youden index were used to determine the cutoff points for the initial and peak KL-6 levels that best predicted 30-day mortality. The association between the initial and peak KL-6 values was assessed by univariate and multivariate logistic regression models. Results: A total of 349 patients were included in this study. The mean initial and peak KL-6 levels were significantly higher in the non-survivor group than in the survivor group. The initial and peak KL-6 values that best predicted 30-day mortality were 491.85 U/mL and 660.05 U/mL, respectively. An initial KL-6 level greater than 491.85 U/mL and a peak KL-6 level greater than 660.05 U/mL were significantly associated with 30-day mortality. Conclusions The initial and peak levels of KL-6 were significantly associated with 30-day mortality in hospitalized patients with COVID-19. These findings suggest that serially monitoring blood KL-6 levels could be a valuable prognostic indicator for COVID-19.

Purpose: To identify the risk factors and effect of empirical glycopeptide on the failure of single arthroscopic debridement for septic knee arthritis in a native knee joint. Materials and Methods: Patients who underwent arthroscopic debridement for septic knee arthritis from March 2005 to December 2022 at one institution were included in this study. Demographic data, comorbidities, preoperative factors including history of previous surgery, history of injection, laboratory data including preoperative C-reactive protein (CRP) and white blood cell (WBC) count, isolated pathogens from synovial fluid culture, and Gachter stage were analyzed. Statistical analyses using univariate and logistic regression were performed. Results: Out of 132 patients, 17 patients (12.9%) had more than one additional arthroscopic debridement. History of diabetes mellitus (DM) (p<0.001), previous injection (p=0.041), isolated Staphylococcus aureus in synovial fluid (p=0.010), and high Gachter stage (p=0.002) were identified as risk factors, whereas age, history of previous knee surgery at the affected knee, CRP level, preoperative WBC, and preoperative neutrophil count of synovial fluid had no significant relation. Logistic regression analysis showed significant increase of risk in patients with DM [odds ratio (OR) 12.002, 95% confidence interval (CI) 3.243–44.418, p<0.001], previous injection history (OR 4.812, 95% CI 1.367–16.939, p=0.017), and isolation of Staphylococcus aureus in synovial fluid (OR 4.804, 95% CI 1.282–18.001, p=0.031) as independent risk factors for failure of infection eradication after single arthroscopic debridement. Conclusion Comorbidity of DM, history of previous injection, isolated Staphylococcus aureus in synovial fluid, and high Gachter stage were associated with a higher risk of failure to eradicate infection with a single arthroscopic procedure. Empirical glycopeptide administration also showed no significant benefit in reducing the risk of additional surgical procedures for infection control, suggesting against the routine administration of glycopeptide.

Background/Aims: Krebs von den Lungen-6 (KL-6) is associated with prognosis in patients with COVID-19. However, there is limited data on the correlation between the prognosis of COVID-19 and varying KL-6 levels at different time points. We investigated the optimal cutoff values of the initial and peak serum KL-6 levels to predict mortality and evaluated their correlation with mortality. Methods: This retrospective cohort study collected data on serially collected serum KL-6 levels in patients hospitalized with COVID-19 between October 2020 and January 2022 at a single tertiary hospital in South Korea. The area under the receiver operating characteristic curve and Youden index were used to determine the cutoff points for the initial and peak KL-6 levels that best predicted 30-day mortality. The association between the initial and peak KL-6 values was assessed by univariate and multivariate logistic regression models. Results: A total of 349 patients were included in this study. The mean initial and peak KL-6 levels were significantly higher in the non-survivor group than in the survivor group. The initial and peak KL-6 values that best predicted 30-day mortality were 491.85 U/mL and 660.05 U/mL, respectively. An initial KL-6 level greater than 491.85 U/mL and a peak KL-6 level greater than 660.05 U/mL were significantly associated with 30-day mortality. Conclusions The initial and peak levels of KL-6 were significantly associated with 30-day mortality in hospitalized patients with COVID-19. These findings suggest that serially monitoring blood KL-6 levels could be a valuable prognostic indicator for COVID-19.

Purpose: To identify the risk factors and effect of empirical glycopeptide on the failure of single arthroscopic debridement for septic knee arthritis in a native knee joint. Materials and Methods: Patients who underwent arthroscopic debridement for septic knee arthritis from March 2005 to December 2022 at one institution were included in this study. Demographic data, comorbidities, preoperative factors including history of previous surgery, history of injection, laboratory data including preoperative C-reactive protein (CRP) and white blood cell (WBC) count, isolated pathogens from synovial fluid culture, and Gachter stage were analyzed. Statistical analyses using univariate and logistic regression were performed. Results: Out of 132 patients, 17 patients (12.9%) had more than one additional arthroscopic debridement. History of diabetes mellitus (DM) (p<0.001), previous injection (p=0.041), isolated Staphylococcus aureus in synovial fluid (p=0.010), and high Gachter stage (p=0.002) were identified as risk factors, whereas age, history of previous knee surgery at the affected knee, CRP level, preoperative WBC, and preoperative neutrophil count of synovial fluid had no significant relation. Logistic regression analysis showed significant increase of risk in patients with DM [odds ratio (OR) 12.002, 95% confidence interval (CI) 3.243–44.418, p<0.001], previous injection history (OR 4.812, 95% CI 1.367–16.939, p=0.017), and isolation of Staphylococcus aureus in synovial fluid (OR 4.804, 95% CI 1.282–18.001, p=0.031) as independent risk factors for failure of infection eradication after single arthroscopic debridement. Conclusion Comorbidity of DM, history of previous injection, isolated Staphylococcus aureus in synovial fluid, and high Gachter stage were associated with a higher risk of failure to eradicate infection with a single arthroscopic procedure. Empirical glycopeptide administration also showed no significant benefit in reducing the risk of additional surgical procedures for infection control, suggesting against the routine administration of glycopeptide.

Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) represents a devastating and growing global threat, calling for new antibiotic treatments. In Korea, the challenge of treating CRAB is compounded by high nosocomial acquisition rates and limited availability of novel antibiotics. Minocycline, a semisynthetic tetracycline derivative, has been proposed as a therapeutic option for CRAB infections. Nonsusceptibility to minocycline may occur through the efflux pump, TetB. The prevalence of tetB in A. baumannii has increased, along with higher minocycline minimum inhibitory concentrations (MICs). We aimed to evaluate minocycline susceptibility rates in clinical strains of CRAB, and the association between tetB carriage and minocycline susceptibility across different genotypes. Materials and Methods: Representative CRAB blood isolates were collected from Asan Medical Center, Seoul.Minocycline susceptibility was assessed using the Clinical and Laboratory Standards Institute (CLSI) breakpoint (≤4 mg/L) and the proposed pharmacokinetics (PK)/pharmacodynamics (PD) breakpoint (≤1 mg/L). Tigecycline was used as a comparator, and its susceptibility breakpoint for Enterobacterales defined by EUCAST was applied (≤0.5 mg/L).The presence of tetB was detected by PCR, and multilocus sequence typing (MLST) was performed using seven housekeeping genes. Results: Of the 160 CRAB blood isolates, 83.8% were susceptible to minocycline by the CLSI criteria, and 50.6% were PK-PD susceptible by the PK-PD criteria. The minocycline minimum inhibitory concentration (MIC)50 /MIC90 was 1/8 mg/L. tetB was present in 49% of isolates and was associated with a higher minocycline MIC (MIC50/90 2/8 mg/L vs. 1/2 mg/L). No clear correlation was observed between tetB positivity and tigecycline MIC. Nine MLSTs were identified, with significant differences in tetB carriage rates between the major sequence types. Notably, ST191, associated with non-tetB carriage and greater susceptibility to minocycline, declined over the study period (P=0.004), while ST451, associated with tetB carriage, increased. Conclusion tetB was present in 49% of CRAB isolates and was associated with higher MICs and non-susceptibility by both CLSI and PK-PD criteria. However, absence of tetB was not a reliable predictor of minocycline PK-PD susceptibility. Additionally, shifts over time towards genotypes with reduced minocycline susceptibility were observed. Further research is needed to correlate these findings with clinical outcomes and identify additional resistance mechanisms.

Background: Meniscal scaffold implantation has been introduced as a treatment for meniscal injuries, but there is still no clear consensus on its clinical impact, including its chondroprotective effect. This review aimed to assess the chondroprotective effects, clinical outcomes, and survivorship of meniscal scaffold implantation compared to meniscectomy, as well as among different types of scaffolds. Methods: A comprehensive search strategy was performed on the databases of PubMed, Embase, Cochrane Library, and Google Scholar, encompassing articles published until June 1, 2024. Randomized controlled trials (RCT) and comparative studies published in English that reported results using collagen meniscal implant (CMI) and polyurethane meniscal scaffold for meniscal tear were included. Results: A total of 421 studies were initially identified across databases, and a systematic review was conducted on 8 studies involving 596 patients. Among the 5 studies that addressed the chondroprotective effect, none found that meniscal scaffolds had a higher chondroprotective effect compared to meniscectomy. In studies comparing CMI and meniscectomy, the Lysholm score results showed a mean difference (MD) range between –5.90 and –4.40. In the case of visual analog scale score, the MD ranged from –1.0 to 1.0. In studies comparing polyurethane meniscal scaffolds and CMI, the Tegner score results showed an MD range of –2.0 to 0.4. Conclusions There was no superiority in chondroprotective effects for both CMI and polyurethane meniscal scaffolds compared to meniscectomy. Although meniscal scaffolds may provide improvements in clinical outcomes, no clinically relevant differences were observed in comparison to meniscectomy. There are no discernible differences between the 2 types of scaffolds.

Background: Periprosthetic fracture (PPF) is a troublesome complication as it utilizes substantial healthcare resources. Recent studies about the epidemiology of PPF after total knee arthroplasty (TKA) are still lacking, and there is limited national-level analysis focusing on the comorbid chronic conditions as risk factors of PPF. This study used national registry data from South Korea and aimed to investigate the epidemiology of PPF following TKA between 2010 and 2020 and identify which comorbidities contributed to the risk of PPF. Methods: Using Health Insurance Review and Assessment (HIRA) service data in South Korea, the incidence of PPF after TKA between 2010 and 2020 was evaluated and stratified by age and sex. Medical comorbidities were evaluated as possible risk factors for PPF using Cox regression analysis. Results: PPF occurred in 14,429 patients, accounting for 2.37% of total TKA patients. The prevalence of PPF by sex was 2.50% in women and 1.64% in men. The PPF rate was 2.82% in under 60 years, 2.25% in 60 to 69 years, 2.42% in 70 to 79 years, 2.29% in 80 to 89 years, and 2.12% in over 90 years. Among 17 analyzed comorbidities, 11 were found to be associated with PPF after TKA. Severe liver disease (hazard ratio [HR], 1.303), hemiplegia (HR, 1.244), and dementia (HR, 1.206) were the top 3 risk factors.Although osteoporosis, pulmonary disease, peptic ulcer, and diabetes showed relatively low HRs than these top 3 factors, the incidence rates were higher. Conclusions PPF occurred in 2.37% of TKA patients in South Korea from 2010 to 2020. PPF rate was higher in women. To prevent PPF after TKA, proper patient management and education should be emphasized, particularly in patients with severe liver disease, hemiplegia, and dementia.