Incidence and Risk Factors of Orthostasis After Primary Hip and Knee Arthroplasty.

Abstract

Postoperative orthostatic intolerance can limit mobilization after hip and knee arthroplasty. The literature is lacking on the incidence and risk factors associated with orthostatic intolerance after elective arthroplasty. A retrospective case-control study of primary total hip, total knee, and unicompartmental knee arthroplasty patients was conducted. Patients with orthostatic events were identified, and potential demographic and perioperative risk factors were recorded. Orthostatic intolerance was defined as postoperative syncope, lightheadedness, or dizziness, limiting ambulation and/or requiring medical treatment. Statistical analysis was completed using Pearson's chi-square test for categorical data and t-tests for continuous data. Binary logistic regression was performed. A total of 500 consecutive patients were included. The overall incidence of orthostatic intolerance was 18%; 25% in total hip arthroplasty (THA) and 11% in total knee arthroplasty. On univariate analysis, significant risk factors for developing postoperative orthostatic intolerance include older age, female gender, THA surgery, lower American Society of Anesthesiologists class, absence of recreational drug use, lower estimated blood volume, lower preoperative diastolic blood pressure, spinal with monitored anesthesia care (MAC), posterior approach for THA, bupivacaine use in spinal, percent of blood loss, postoperative oxycodone or tramadol use, higher postoperative intravenous fluid volume, and lower postoperative hemoglobin. Multivariate analysis demonstrated persistent significance of female gender, THA surgery, spinal with MAC, bupivacaine use in spinal, and more intravenous fluid administered postoperatively. Orthostatic intolerance affects a significant number of arthroplasty patients. Awareness of risk factors and modification of perioperative variables linked to orthostatic intolerance may assist the surgeon in choosing the appropriate surgical setting, educating patients, and improving early postoperative recovery.