Background: Early diagnosis of knee osteoarthritis (OA) remains a diagnostic challenge. Urinary C-terminal crosslinked telopeptide of type II collagen (urinary CTX-II) is one of the potential OA biomarkers. However, conclusive evidence regarding the use of this biomarker as a tool for early diagnosis is still lacking. The purposes of this study were to compare urinary CTX-II levels in patients with knee OA and in healthy controls, to evaluate the correlation between urinary CTX-II levels, radiographic severity of OA, and patient-reported outcomes and to evaluate the effect of age and gender on urinary CTX-II levels in the Asian populations. Methods: Two groups were studied. The OA group included 78 patients with knee OA aged > 40 years who met the diagnostic criteria for knee OA described by the American College of Rheumatology (ACR). The control group consisted of 51 healthy participants age > 40 years without clinical or radiographic evidence of knee OA. Bilateral knee radiographs were taken and classified according to the Kellgren and Lawrence (KL) grading system. Urinary CTX-II was measured using a competitive ELISA test and Western Ontario and Mcmaster Universities Arthritis Index (WOMAC) was also recorded in all participants. Results: Urinary CTX-II was significantly higher in the OA group than in the control group (p < 0.001). The severe knee OA group (KL grade 3 and 4) had higher urinary CTX-II levels than mild knee OA group (KL grade 2) but the difference did not reach statistical significance (p = 0.2). There was a moderate correlation between urinary CTX-II levels and KL grades (r = 0.405, p < 0.001) and a weak correlation between urinary CTX-II levels and WOMAC index scores (r = 0.367, p < 0.001). Multiple regression analysis showed that urinary CTX-II was independently associated with KL grades. Whereas age, gender, and WOMAC index had no statistically significant influence on the urinary CTX-II levels.Conclusions: Patients with knee OA had higher urinary CTX-II levels than healthy controls. Moreover, levels of urinary CTX-II were independently correlated with radiographic severity of knee OA. Age, gender, and patient-reported outcomes exerted no effect on the urinary CTX-II levels.Level of evidence: Diagnostic Level III.

Introduction:Main population of total knee arthroplasty are elderly group which contained of risks from procedure and medical condition. The amount of blood loss in TKA vary in different studies. Blood loss from TKA may cause the change of hemodynamic status, risked to cardiovascular morbidity or mortality. Allogenic blood transfusion, associated with many immunological and transfusion complications, increased cost of surgery. Factors associated with blood loss should controlled to decreased blood loss and complications. Objectives:Determination of risk factors for blood loss is a significant step toward blood management. This study is also used calculated blood loss, which more accurate than visible blood loss. Methods:Medical records of 517 patients who underwent TKA from 2011 to 2016 were examined, blood loss was calculated by Gross' formula. Pearson 's correlation and multiple regression analyses were performed to identify factors associated to blood loss. Results:The mean calculated blood loss decreased yearly from 602.94ml to 107.78ml in 2016. There is “zero” transfusion in 2016. Radivac drain, patellar resurfacing, modified Robert Jones bandage and higher postoperative pain score related to increased blood loss after TKA according to Pearson's correlation. Multiple regression analysis revealed significant independent predictors related to blood loss are radivac drain, intravenous tranexamic acid, postoperative pain score and body mass index. Conclusions :Awareness in low BMI patient, avoid radivac drain, routine using of intravenous tranexamic acid and good postoperative pain control can reduce blood loss and transfusion for a patient undergoing TKA.