Well-controlled medical conditions. No significant cardiac disease (e.g., recent MI or unstable angina, uncontrolled arrhythmia). No uncontrolled diabetes (avoid outpatient TJA if insulin-dependent with poor control) [26]. No untreated obstructive sleep apnea requiring overnight monitoring. No active bleeding disorders, cirrhosis, end-stage renal disease, or other major unstable conditions [26]. (Any chronic conditions such as hypertension, COPD, etc., should be optimized pre-op.) This evidence concerns the gene INS and cardiac arrhythmia.