Have we come to the end of the PROM? Wearable sensors highlight improved rate of recovery and range of movement following robotic-assisted TKA that are overlooked by conventional PROMs

The purpose of this study was to evaluate early outcomes of patients that 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 ankle-worn 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, EuroQol Visual Analogue Scale, and Forgotten Joint Score, were evaluated at pre-operative baseline, weeks 2 to 6 post-operatively, and at 3-months and 1-year follow-up. By post-operative week 6, RA-TKA patients showed improved function compared to the conventional TKA group, with increased maximum knee flexion angle (118 ^o ± 6.6 ^o vs 113 ^o ± 5.4 ^o ; p=0.04), improved symmetry in regard to limb loading (82.3% vs 22.4%; p<0.01), increased cumulative impact load (146.6% vs 37%; p<0.01), and increased bone stimulus (25.1% vs 13.6%; p<0.01). RA-TKA patients demonstrated an earlier return to symmetrical limb loading compared to conventional TKA by post-operative week 3. There were no differences in PROMs between the two groups at any timepoint. RA-TKAs were associated with faster return of normal gait and improved range of motion when assessed using IMUs compared to conventional TKA, which were not detected by traditional PROMs during the early post-operative period.