Abnormal preoperative platelet count may predict postoperative complications following shoulder arthroplasty

Background: The purpose of this study is to investigate the association between preoperative platelet counts and postoperative complication rates within 30 days of total shoulder arthroplasty (TSA). Methods: The American College of Surgeons National Surgical Quality Improvement database was queried for all patients who underwent TSA between 2015 and 2019. The study population was then divided into 5 groups based on their preoperative platelet count: <100k (moderate-to-severe thrombocytopenia), 100-150k (mild thrombocytopenia), 150-200k (low-normal preoperative platelet count), 200-450k (normal, reference cohort), and >450k (thrombocytosis). Postoperative complications within 30 days of the TSA were collected. Multivariate logistic regression analysis was conducted to investigate the relationship between preoperative platelet counts and postoperative complications. Results: A total of 19,721 patients undergoing TSA between 2015 and 2019 were included in this study. One hundred fifty-five patients (0.8%) had moderate-to-severe thrombocytopenia, 982 (5.0%) had mild thrombocytopenia, 3945 (20.0%) had a low-normal preoperative platelet count, 14,386 (72.9%) had a normal preoperative platelet count, and 253 (1.3%) had thrombocytosis. An increasing rate of overall complications was observed as the severity of thrombocytopenia progressed from low-normal (6.4%) to mild thrombocytopenia (10.2%) and to moderate-to-severe thrombocytopenia (18.7%). The overall complication rate of the thrombocytosis cohort was 14.6%. In comparison to normal platelet count, low-normal thrombocytopenia, mild thrombocytopenia, moderate-to-severe thrombocytopenia, and thrombocytosis were identified by multivariate analysis as significant predictors of overall complications (odds ratios [ORs] of 1.12, 2.15, 2.43, 2.71, respectively), postoperative anemia requiring transfusion (ORs of 1.63, 3.45, 5.97, 4.21, respectively), and minor complications (ORs of 1.39, 2.64, 3.40, 3.34, respectively). Minor complications include progressive renal insufficiency, urinary tract infection, transfusions within 72 hours after surgery, pneumonia, and superficial incisional surgical site infection. Conclusion: Increasing severity of thrombocytopenia correlated with higher overall postoperative complication rates following TSA. Interestingly, patients with thrombocytosis had the highest overall postoperative complication rates among all cohorts included in this study. Platelet counts are often the reflection of other comorbidities and a good indicator of patient's general health status. Long-term optimization of abnormal platelet counts may potentially reduce surgical complications.