Continuous preoperative activity patterns measured by wearable sensors are associated with recovery after total knee...

Physical activity is increasingly recognized as an important factor in recovery after orthopedic surgery, but objective evidence remains limited. This study examined whether wearable-derived preoperative activity levels were associated with recovery outcomes following Total Knee Arthroplasty (TKA).

In this prospective longitudinal study, 30 adults undergoing unilateral TKA for knee osteoarthritis wore validated thigh-mounted accelerometers for up to two weeks preoperatively and for three months postoperatively. Participants were classified into low-, moderate-, and high-activity groups based on preoperative 24-hour activity intensity profiles. Recovery was assessed using continuous accelerometer-derived activity metrics and patient-reported outcomes (PROMs), including the Knee injury and Osteoarthritis Outcome Score (KOOS).

Higher preoperative activity levels were associated with more favorable objective recovery after TKA. Compared with the low-activity group, the high-activity group showed higher postoperative activity intensity and total steps, with 2.6-fold higher activity intensity and 2.2-fold higher total steps. During the first postoperative month, the high-activity group also showed faster increases in activity intensity and total steps. In contrast, KOOS subscale scores improved over time but did not differ significantly between activity groups.

The findings of this study highlight the importance of accounting for baseline activity when interpreting wearable-derived postoperative recovery patterns. They also suggest that objective monitoring can provide information on functional recovery that may not be captured by PROMs.