This study evaluates a wearable plantar-pressure insole system (EUKINES) designed to support gait training during postoperative rehabilitation after primary total hip arthroplasty (THA). The trial will include 200 adults who are randomly assigned to one of four rehabilitation programs: EUKINES with real-time biofeedback, EUKINES without biofeedback, a certified commercial reference system with biofeedback, or standard rehabilitation without any gait-analysis device. All participants will receive a structured 6-week rehabilitation program after THA, and the only differences between groups concern the use of gait-analysis technology and biofeedback. The main outcomes include changes in plantar-pressure-based gait parameters (mean foot pressure and load asymmetry) and standard clinical scores of hip function and symptoms. The study will also monitor safety, device-related events, walking speed, pain, and patient and therapist ratings of usability and satisfaction. The goal is to determine whether rehabilitation supported by the EUKINES insole system is at least as effective and safe as rehabilitation supported by a certified reference system and as standard care, and to explore the feasibility of using low-cost, printed-sensor technology for routine gait assessment and future telerehabilitation.

This is a prospective, randomized, partially blinded, multicenter clinical trial with a non-inferiority design conducted in patients undergoing primary total hip arthroplasty (THA) for advanced osteoarthritis. The study is embedded in the EUKINES project, which develops low-cost, printable pressure sensors and a wearable plantar-pressure insole system intended for scalable clinical rehabilitation and telerehabilitation use. The trial evaluates the clinical performance, safety, and usability of the EUKINES insole system as an adjunct to standard postoperative rehabilitation.

Adult patients scheduled for primary THA will be screened according to predefined inclusion and exclusion criteria and enrolled after providing written informed consent. A total of 200 participants will be randomized in blocks to one of four parallel rehabilitation arms: (1) EUKINES with real-time biofeedback, (2) EUKINES without biofeedback (data recording only), (3) a certified commercial reference gait-analysis system with biofeedback, or (4) standard rehabilitation without any gait-analysis device. All participants will follow the same structured 6-week rehabilitation program after surgery, including routine physiotherapy and six additional, approximately 3-hour gait-focused sessions. The content and duration of rehabilitation are equivalent across groups; only the use of gait-analysis devices and biofeedback differs between arms.

Outcome assessments will be performed at baseline and during postoperative follow-up. Primary endpoints include changes in plantar-pressure-derived gait parameters such as mean foot pressure and load asymmetry between the operated and non-operated limb, as well as changes in hip-related clinical scores (Harris Hip Score and the 12-item Hip Disability and Osteoarthritis Outcome Score, HOOS-12) and the incidence of adverse events and device-related complications. Secondary outcomes include extended spatiotemporal gait parameters, 10-Meter Walk Test performance, pain intensity and satisfaction with surgery and rehabilitation, and patient and therapist ratings of usability, comfort, and perceived usefulness of the EUKINES and reference systems. All plantar-pressure time-series data will be stored to allow post-hoc derivation of additional gait metrics and exploratory analyses.

The study is classified as a low-risk, add-on interventional trial that does not alter standard surgical procedures or baseline postoperative care. Device-assisted rehabilitation sessions are provided as an adjunct to routine practice. The trial is conducted in accordance with the Declaration of Helsinki and Good Clinical Practice, under the oversight of a bioethics committee. By directly comparing the EUKINES prototype with a certified commercial reference system and standard care, the study aims to demonstrate the feasibility and clinical usefulness of an affordable sensor-based gait-analysis platform and to provide a basis for future development of data-driven telerehabilitation and personalized rehabilitation strategies.

Inclusion Criteria:

• Age 18 years or older.
• Scheduled for primary total hip arthroplasty performed for advanced osteoarthritis or other degenerative hip disease.
• Willingness and ability to participate in the 6-week postoperative rehabilitation program and follow-up assessments.
• Ability to understand study information and provide written informed consent.

Exclusion Criteria:

• Coexisting medical conditions that may significantly affect rehabilitation outcomes or gait (e.g., severe neurological disorders, major lower-limb joint trauma, other significant musculoskeletal pathology).
• Cognitive impairment or psychiatric conditions that would preclude effective cooperation with the rehabilitation and research team.
• Any contraindication to participation in additional gait training sessions or use of the insole-based gait-analysis systems as judged by the treating physician.

Individual participant data will not be shared because there is no dedicated infrastructure or funding for long-term controlled access data sharing beyond the requirements for publication and regulatory reporting.

Outcome assessors responsible for postoperative follow-up visits and clinical evaluations are blinded to group allocation. Patients, care providers, and rehabilitation staff are aware of the assigned intervention because of the visible use or non-use of gait-analysis devices.