Active Ankylosing Spondylitis Increases The Blood Loss Of Total Hip Arthroplasty

Purpose:For ankylosing spondylitis(AS)patients with end-staged hip involvement,total hip arthroplasty(THA)is the most effective treatment to relief symptoms,restore joint activities and improve the quality of life.Previous researches have proposed that AS patients undergoing THA might suffer amount of blood loss,which leads to high prevalence of allogenic transfusion and complications.The purpose of the present study is to investigate the influential factors of blood loss of total hip arthroplasty for patients with ankylosing spondylitis,with which we hope it can provide clinical guidance upon making effective strategy to reduce blood loss and improve the operation safety.Methods and Patients:This is a retrospective study which enrolled 73 AS patients with end-staged hip involvement who received primary unilateral THA from the year 2011 to 2016 in our department.Patients' demographics,surgical protocol,laboratory test result,blood loss and transfusion were collected and analyzed.Ankylosing spondylitis disease activity score(ASDAS)was used to evaluate the disease activity of AS.The Orthopedic Surgery Transfusion Hemoglobin European Overview(OSTHEO)formula was used to estimate the blood loss.Multivariate line regression and stepwise analysis was employed to explore the influential factors of THA blood loss,in which the blood loss of THA was independent variable and 16 potential risk factors were covered as variables,including gender,age,BMI,disease duration,operation time,preoperative laboratory test results and the utilization of hemostatic.According to the result of multifactor line regression analysis,univariate line regression analysis was used to further confirm the correlation.Patients were assigned to two groups according to disease activity index(ASDAS).The cohort study was performed to further confirm the hypothesis that AS patients at active disease stage might increase the blood loss of THA.Result:44 patients were eligible for the study,including 5 females and 39 males.The mean age was31.7±10 years and the mean BMI was 21.30±3.01 kg/m2.The average blood loss of AS patients receiving THA reached 1735.19±756.04mL and the allogenic transfusion rate was 79.5%with an average volume of 1.86u.The multivariate line regression and stepwise analysis suggested that ASDAS,preoperative fibrinogen concentration,operation time were correlated with the blood loss.Univariate line regression analysis suggested that ASDAS,allogenic transfusion volume and the fall of hematocrit was respectively associated with blood loss,which was a linear correlation.As for the result of cohort study,16 patients(36%)were included in active disease group(ASDAS>1.3)while 28 patients(64%)were in stable disease group(ASDAS<1.3).The blood loss in stable disease group was 1359.69±474.03mL while it reached 1949.76±798.11mL in active disease group.More blood loss was found in active disease group that in stable disease group,which showed statistical difference(P=0.010).Conclusion:ForAS patients undergoing THA,disease activity is positively correlative with blood loss.Patients with active disease might suffer much more blood loss compared to the patients with stable disease.The disease activity of AS should be controlled as low as possible to reduce the blood loss and improve the operation safety.