Have we come to the end of the patient-reported outcome measure (PROM)? : wearable sensors highlight improved rate of recovery and range of motion following robotic-assisted total knee arthroplasty that are overlooked by conventional PROMs.

Abstract

The purpose of this study was to evaluate early outcomes of patients who underwent robotic-assisted total knee arthroplasty (RA-TKA) and conventional TKA using wearable sensors and traditional patient-reported outcome measures (PROMs). This was a prospective, matched, parallel cohort study of 100 patients with symptomatic end-stage knee osteoarthritis undergoing primary TKA (44 RA-TKA, 56 conventional TKA). Functional outcomes were assessed using wearable inertial measurement units (IMUs). IMU-based outcomes included impact load, impact asymmetry, maximum knee flexion angle, and bone stimulus. PROMs, including Oxford Knee Score, EuroQol five-dimension five-level questionnaire, EuroQol visual analogue scale, and Forgotten Joint Score, were evaluated at preoperative baseline and weeks 2 to 6 postoperatively. By postoperative week 6, RA-TKA patients showed improved function compared with the conventional TKA group, with increased maximum knee flexion angle (118° (SD 6.6°) vs 113° (SD 5.4°); p = 0.038), improved symmetry with regard to limb loading (82.3% (SD 16.1) vs 22.4% (SD 9.5); p < 0.001), increased cumulative impact load (146.6% (SD 16.7) vs 37% (SD 8.1); p < 0.001), and increased bone stimulus (25.1% vs 13.6%; p = 0.003). RA-TKA patients demonstrated an earlier return to symmetrical limb loading compared with conventional TKA by postoperative week 3. There were no significant differences in PROMs between the two groups at any timepoint. RA-TKAs using personalized alignment were associated with faster return of symmetrical gait and improved range of motion when assessed using IMUs compared with conventional TKA, which were not detected by traditional PROMs during the early postoperative period.