The Necessity Of Routine Postoperative Laboratory Tests In Enhanced Recovery After Surgery For Primary Total Hip Arthroplasty

Objective: Recently,the justification of the practice of ordering routine postoperative laboratory tests for patients undergoing primary total hip arthroplasty(THA)has been challenged,especially in the context of implementation of enhanced recovery program in THA.This study aimed to evaluate the utility of routine postoperative laboratory tests in enhanced recovery after surgery for primary THA,and identify risk factors associated with abnormal postoperative laboratory results.Methods: A retrospective review was performed on 608 consecutive patients who underwent primary THA between 2016 and 2018 at a single tertiary academic center.Patients' demographics,comorbidities,surgical characteristics,preoperative and postoperative laboratory test results were collected.The primary outcomes were the rates of acute blood anemia requiring transfusion,hypoalbuminemia requiring albumin supplementation.Univariate analysis was performed with Chi-square test.Multivariate logistic regression analysis was also performed to identify therisk factors associated with abnormal laboratory tests.Results: A total of 594 patients(97.7%)had abnormal postoperative laboratory tests,majority of which were exclusively due to anemia or hypoalbuminemia.Of the 497 patients(81.7%)with postoperative anemia,25 patients(4.1%)were transfused.Factors associated with blood transfusion were female,lower BMI,longer operative duration,lower preoperative hemoglobin.Of the 566 patients(93.1%)with postoperative hypoalbuminemia,58 patients(9.5%)received albumin supplementation.Factors associated with albumin supplementation were female,lower BMI,hip fracture,diabetes,longer operative duration,preoperative hypoalbuminemia.Sixty-nine patients(11.3%)had abnormal postoperative creatinine,and 8 patients(1.3%)requiring medical intervention.Regarding Na abnormalities,hyponatremia was responsible for all Na abnormalities,18 patients had mild hyponatremia,and 1 patient had moderate hyponatremia,all had no treatment.For abnormal postoperative K levels,19 patients(3.1%)developed hyponatremia and 9 patients(1.5%)received potassium supplementation.For abnormal postoperative Ca levels,279(45.9%)with hypocalcemia and 3 patients(0.5%)received calcium supplementation.Conclusion: This study provides additional clinical evidence that routine postoperative laboratory tests are not necessary in modern primary unilateral THA.However,for patient with identified risk factors,postoperative laboratory tests should remain be obtained after THA.