Routine Postoperative Hemoglobin and Hematocrit Tests Are Unnecessary Following Primary Total Hip and Knee Arthroplasty.

Background: Acute blood loss and transfusion are recognized risks factors of total hip (THA) and total knee arthroplasty (TKA). This study aimed to investigate the clinical value of immediate postoperative hemoglobin and hematocrit (H&H) tests following primary elective THA and TKA. Methods: This retrospective observational study was undertaken at a single academic hospital. Medical records were reviewed for a consecutive series of patients undergoing primary elective THA and TKA over a 12-month period. Patient demographic data; the use of preoperative anticoagulants; preoperative and postoperative blood test results; and the incidence of postoperative allogenic blood transfusion (ABT) were collected. The primary outcome measure was the incidence of postoperative ABT prescribed in response to the immediate postoperative H&H result. Results: Overall, 367 eligible patients were included, with 167 THA (46%) and 200 TKA (54%) cases. Only 3 patients (0.8%) received a postoperative ABT; none on the day of surgery or on postoperative day 1. Immediate postoperative H&H tests were drawn in 246 patients (67%), but it did not influence clinical decision-making with regards to transfusion. No significant differences in ABT were observed in relation to patient age, sex, body mass index, operation (THA or TKA), or the use of preoperative anticoagulation medication. The incidence of ABT was significantly higher in patients with a combined preoperative hemoglobin <12.5 g/dL and hematocrit <40.0% ( Conclusions: The incidence of postoperative blood transfusion following primary elective THA and TKA was low at 0.8%. Postoperative H&H tests were drawn in most patients but did not influence clinical management. Immediate postoperative hematological monitoring is unnecessary for most low-risk patients following uncomplicated primary elective THA and TKA.