Patient-Centric Design and Preliminary Clinical Verification of a Knee Exoskeleton for Gait Rehabilitation After Total Knee Arthroplasty

Total Knee Arthroplasty (TKA) is an effective treatment for patients suffering from severe knee osteoarthritis. However, the success of postoperative functional recovery is closely related to early ambulation after surgery, especially in the acute phase. Although lower-limb exoskeletons have been used for gait training, existing devices are not suitable for post-TKA patients in the acute phase. In this study, we propose a portable, rigid-soft hybrid knee exoskeleton for post-TKA patients. The exoskeleton employs a patient-centric design to address postoperative challenges. Considering weak physical mobility, joint instability, and inability to walk on a treadmill, the mechanical design integrates a lightweight, joint-free linear actuator, paired with a portable actuation unit for overground ambulation. To accommodate substantial interpatient kinematic variability and weakened postoperative joint control, the high-level control system implements a personalized trajectory generator and a patient-in-loop modeling pipeline. The results of the clinic test showed that after gait training, the maximum knee angle of patients increased from$16.45^{\circ }$to$26.43^{\circ }$, and the knee angle range improved from$12.64^{\circ }$to$24.46^{\circ }$. The preliminary clinic experiment showed that the portable system might be safe and feasible for patients. These findings suggest that our proposed exoskeleton-based intervention is a potential approach for acute-phase gait training of TKA patients.