Abstract
Increased postoperative physical activity is thought to be useful in preventing postoperative cognitive dysfunction (POCD) in elderly patients after lower extremity orthopedic surgery. This study aims to clarify the effect of postoperative physical activity on the course of bottom-up attention in elderly postoperative lower extremity orthopedic surgery patients. The study enrolled 22 patients aged ≥65 years who were admitted to the Hospital for total knee or total hip replacement surgery. The study design was a single-center longitudinal study. The subjects' Posner task reaction time was measured preoperatively, postoperatively on day 7, and postoperatively on day 14. The amount of physical activity from postoperative on day 1 to postoperative day 14 was also measured using an accelerometer. Based on the measured physical activity, the subjects were divided into a high physical activity group (n = 11) and a low-physical activity group (n = 11) for statistical analysis. The results of 2-way analysis of variance revealed a significant interaction for reaction times to the Posner task in the invalid trials (F2,20 = 4.77, P = .02). Subsequent within-group 1-way analysis of variance indicated a substantial change in invalid trial reaction times in the high physical activity group (F2,20 = 6.85, P = .005). Multiple comparisons revealed significant improvements from preoperative measurements to postoperative day 14 in the high physical activity group (t10 = 3.81, P = .003). Between-group comparisons at each time point demonstrated significantly longer invalid trial reaction times in the low-physical activity group compared to the high physical activity group on postoperative day 14 (t20 = 2.92, P = .01). No significant differences were found in the Mini Mental State Examination at all-time points. In older patients who underwent postoperative lower extremity orthopedic surgery, those with high postoperative physical activity levels were less likely to have a decrease in bottom-up attention compared with those with low postoperative physical activity levels. Increased physical activity may be a beneficial physical therapy intervention in the prevention and improvement of postoperative cognitive dysfunction.