Routine postoperative laboratory tests are unnecessary after primary reverse shoulder arthroplasty.

Background: Obtaining postoperative laboratory studies after primary reverse shoulder arthroplasty (RSA) is a common practice. However, justification of this practice remains unclear. This study assesses the utility of routine postoperative laboratory studies in RSA.

Methods: The electronic medical records of 369 patients who underwent RSA over 10 years were retrospectively reviewed. A total of 213 patients qualified for analysis. Primary outcomes were intervention related to abnormal laboratory values, length of stay, and 90-day emergency department visits/readmissions. Multivariate logistic regression analysis was performed to identify risk factors associated with abnormal laboratory values and postoperative visits/readmissions.

Results: Of 213 patients analyzed, 188 (88.7%) had abnormal postoperative laboratory values: 69% had an abnormal hemoglobin (Hgb) or hematocrit level, but only 12% underwent interventions. Lower preoperative Hgb was a significant predictor of receiving a transfusion. A significant association existed between abnormal postoperative electrolyte and creatinine levels with lower body mass index (BMI) and higher Charlson Comorbidity Index (CCI). Only 4 patients (1.8%) received non-transfusion related intervention. Emergency department visits were not statistically different between patients with positive or negative laboratory tests (P = .73).

Conclusion: Because 87.3% of laboratory studies did not influence patient management, we recommend against routine testing for primary RSA. This study demonstrates that the practice of obtaining routine postoperative laboratory studies is not justified. We recommend selectively obtaining a postoperative basic metabolic profile in patients with increased American Society of Anesthesiologists classification and/or CCI with a lower BMI. We also recommend selectively ordering postoperative complete blood count in patients with a lower preoperative Hgb.