Is Routine Hemoglobin Monitoring Necessary after Elective Hip and Knee Arthroplasty?

BACKGROUND: Many orthopaedic units measure hemoglobin (Hb) levels after primary joint arthroplasty to identify patients with postoperative anemia. With the refinement of surgical techniques, blood loss in primary arthroplasty has decreased. The aim of this study was to investigate the postoperative Hb monitoring and transfusion practices in our own institution after elective hip or knee arthroplasty. METHODS: We conducted a retrospective audit of all patients who underwent elective total hip or knee arthroplasty in Galway University Hospital between March 1 and June 1, 2019. We recorded when they underwent postoperative Hb testing, whether or not they had a drop of Hb, which would indicate transfusion (<8 g/dL), and whether or not they were transfused. In patients who underwent transfusion, a chart review was performed to establish the presence of factors that would have triggered repeat Hb testing. RESULTS: One hundred thirty-six patients underwent elective primary hip or knee arthroplasty in the period. All had a full blood count sent on the first postoperative day. None (0%) had a clinically significant (to < 8g/dL) postoperative Hb drop on day 1. Eighteen (13.2%) patients underwent repeat testing on day 2 or subsequently. Eight (5.9%) exhibited a drop in Hb to less than 8 g/dL, with a mean Hb drop of 4.26 (standard error of the mean ± 0.862, standard deviation ± 0.98), and 5 (3.7%) proceeded to undergo allogenic blood product transfusion. All 5 underwent documented indications for repeat Hb testing. CONCLUSIONS: There is no evidence for performing routine Hb testing on day 1 after elective hip or knee arthroplasty. We recommend that postoperative Hb testing should only be carried out on patients with additional indications.