Agreement Between Wearable-based Vital-sign Monitoring and Standard Bedside Monitoring in Patients After Knee Arthroscopy

Postoperative vital sign monitoring is essential for early detection of inpatient hemodynamic and respiratory complications. Although conventional bedside monitors serve as the clinical gold standard, their fixed design limits patient mobility and continuous ambulatory monitoring, which hinders early rehabilitation after orthopedic surgery. Wearable monitoring devices have shown great potential for postoperative vital sign surveillance due to their mobility and continuous data collection capabilities, yet real-world validation data in orthopedic postoperative patients remain insufficient, and wearable blood pressure measurement accuracy remains controversial. This study aimed to evaluate the agreement between a wearable monitor and a standard bedside monitor for heart rate, respiratory rate, systolic blood pressure, diastolic blood pressure, and peripheral oxygen saturation (SpO 2 ) in patients undergoing knee arthroscopy. A total of 100 elective knee arthroscopy patients were prospectively enrolled. Paired vital sign data were collected simultaneously via the two devices at four daily time points over two postoperative days. Intra-class correlation coefficient (ICC), Lin’s concordance correlation coefficient, Bland-Altman analysis, temporal trend analysis, and clinical acceptability evaluation were performed for statistical assessment. After excluding five missing values, 3995 paired observations were analyzed. The wearable device showed excellent agreement for heart rate (ICC = 0.994, bias = −0.63 bpm, 95% LoA: −2.97 to 1.70 bpm), good agreement for respiratory rate (ICC = 0.940, bias = −0.51 breaths/min, 95% LoA: −2.71 to 1.68 breaths/min), and moderate-to-good agreement for SpO2 (ICC = 0.872, bias = −0.85%, 95% LoA: −3.50 to 1.80%). Diastolic blood pressure showed moderate agreement (ICC = 0.827, bias = −1.42 mmHg, 95% LoA: −12.90 to 10.06 mmHg), while systolic blood pressure demonstrated the lowest agreement (ICC = 0.811) with a prominent positive systematic bias of 5.63 mmHg. Temporal trends remained stable across postoperative days, with consistent inter-device bias over time. The clinical acceptability rates of heart rate, respiratory rate and SpO 2 exceeded 99.5%, compared with 92.2% for diastolic blood pressure and only 79.6% for systolic blood pressure. In conclusion, the wearable monitor provides reliable heart rate, respiratory rate, and SpO2 measurements and is suitable for routine postoperative monitoring after knee arthroscopy. However, blood pressure measurements, particularly systolic blood pressure, show notable systematic deviation, and targeted algorithm calibration is needed to improve its blood pressure monitoring performance.