BACKGROUND Myocardial injury after noncardiac surgery (MINS) is common and associated with postoperative mortality. We assessed MINS occurrence and association with 30-day and long-term mortality in older adult patients undergoing orthopedic surgery in China. MATERIAL AND METHODS This was a retrospective study of consecutive patients who underwent orthopedic surgery between January 1, 2009, and December 31, 2017, at Beijing Jishuitan Hospital. MINS was defined as postoperative troponin I peak elevation above the 99th percentile upper reference limit (>0.034 µg/L) within 30 days after surgery. Outcomes were 30-day postoperative mortality and long-term all-cause mortality. RESULTS From 34 901 patients, 5897 (16.9%) had serial troponin I measurements, and 266 (4.5%) had MINS after surgery. Mean patient age was 71.1±9.2 years; 32.9% were male. Among patients with MINS, 180 had myocardial infarction (MI) (3.2%). Patients with MI had higher 30-day and long-term mortality than those without MI (8.9% vs 1.2%; P<0.016 and 18.9% vs 3.5%; P=0.001). Male sex (OR 5.87, 95% CI 1.75-19.67; P=0.004), RCRI ≥2 (OR 5.05, 95% CI 1.67-15.31; P=0.004), and MI (OR 9.13, 95% CI 1.13-73.63; P=0.011) were independently associated with 30-day mortality. Age (HR 1.07, 95% CI 1.03-1.11; P=0.001), male sex (HR 2.96, 95% CI 1.51-5.80; P=0.002), RCRI ≥2 (HR 2.01, 95% CI 1.03-3.94; P=0.041), orthopedic trauma (HR 3.40, 95% CI 1.00-11.44; P=0.049), and MI (HR 7.33, 95% CI 2.22-24.20; P=0.001) were predictors of 2-year mortality. CONCLUSIONS Perioperative MI was independently associated with 30-day and long-term mortality after orthopedic surgery, providing a potential indicator of high risk of mortality in patients who could benefit from targeted prevention and intervention.