Gait is an essential daily activity performed through the complex coordination of the central and peripheral nervous systems and the musculoskeletal system. Gait disorders can negatively affect quality of life, increase the risk of falls, decrease the ability to perform daily activities, and limit physical activity. Various musculoskeletal diseases can cause gait impairment, with hip osteoarthritis and osteonecrosis of the femoral head (ONFH) being the most representative conditions.

Various interventions can be attempted during the early stages of hip joint disease progression. However, improvement in symptoms does not necessarily indicate a halt in disease progression. As the condition advances in most patients, thinning of the full-thickness hip cartilage or collapse of the femoral head occurs, leading to restricted hip range of motion, weakness of the lower limb muscles and functional deterioration, resulting in the need for total hip arthroplasty.

THA offers significant improvements in pain relief and function, regardless of the patient's preoperative status, and can reduce long-term healthcare costs. However, performing THA at an early stage with minimal functional improvement is not recommended. Postoperative complications, such as infections, aseptic loosening, and instability, are potential risks, with younger patients aged 45-64 showing higher revision surgery rates compared to those aged 65 and older. This highlights the need for new interventions that can delay the time to surgery while improving gait function and muscle strength.

Therefore, this study aims to explore the clinical feasibility of the Angel Suit H10 (Angelrobotics, Seoul, Korea) by assessing whether wearing the Electrically Powered Orthopedic Exercise Device improves gait function in patients with hip joint diseases, along with evaluating user satisfaction and device safety.

(1) Overview of study design This investigator-initiated exploratory study is a pilot study designed to evaluate the effectiveness and safety of the Electrically Powered Orthopedic Exercise Device by measuring and analyzing gait function and balance ability in patients with hip joint diseases under both non-wearing and wearing conditions.

(2) Experimental Group and Evaluation Procedures

1. Participant Selection:

   This study includes a single test group with a total of 30 participants. The selection of participants for the electrically powered orthopedic exercise device and the overall study process will be conducted under the prescription and guidance of a rehabilitation medicine specialist, and supervised by assistants (physicians and occupational therapists). The examiner will collect clinical information and conduct a screening assessment for each participant.

2. Evaluation Phase Without Device:

   After the screening test, participants undergo assessments of walking ability and balance without wearing the motorized orthopedic exercise device. A 10-minute rest period is provided between each assessment. If the participant wishes, additional rest time is allowed and recorded in the case report form. The assessments include the 10-Meter Walk Test, the 6-Minute Walk Test, the Timed Up and Go Test, and the Berg Balance Scale. These evaluations are conducted in the rehabilitation function testing room on the second floor of the facility under the supervision of the research team (physician and either a physical or occupational therapist).

3. Pre-Adaptation Phase:

   After the evaluations without the device, a total of four adaptation sessions are conducted, during which the participant wears the device and performs short-distance walking within 10 meters. These sessions are designed to help the participant become familiar with the operation and wearing method of the H10 device. Appropriate device settings are configured for each participant to minimize any potential inexperience or anxiety during use. Participants must complete all four adaptation sessions, and each session should be conducted within a two-week interval.

4. Evaluation Phase:

After completing all four adaptation sessions, participants undergo assessments of walking ability and balance while wearing the motorized orthopedic exercise device. A 10-minute rest period is provided between each assessment. If the participant wishes, additional rest time is allowed and recorded in the case report form. The assessments include the 10-Meter Walk Test, the 6-Minute Walk Test, the Timed Up and Go Test, and the Berg Balance Scale. These evaluations are conducted in the rehabilitation function testing room on the second floor of the facility under the supervision of the research team (physician and either a physical or occupational therapist). After the evaluations are completed, a usability and satisfaction survey regarding the motorized orthopedic exercise device is conducted.

Inclusion Criteria:

1. Individuals aged 19 or older
2. Individuals diagnosed with hip osteoarthritis of Kellgren-Lawrence (K-L) Grade 1-4
3. Individuals diagnosed with avascular necrosis of the femoral head at Association Research Circulation Osseous(ARCO) Stage 1-4
4. Individuals able to sit at the edge of a bed without assistance and stand for 10 seconds regardless of support
5. Individuals who are Functional Ambulatory Category (FAC) score of 1-3
6. Individuals who visited Yongin Severance Hospital, understood the study, and signed informed consent
7. Individuals who have adequate cognitive ability (Korean Mini-Mental State Examination score ≥ 20)

Exclusion Criteria:

1. Individuals who have contraindications for lower limb weight-bearing such as severe joint contractures, osteoporosis, or untreated fractures
2. Individuals who have progressive or unstable brain diseases or neurological paralysis from stroke
3. Individuals who have active infections or open wounds hindering device use
4. Individuals who have significant leg length discrepancies
5. Individuals who have severe deformities or contractures in the lower extremities
6. Individuals who have history of poliomyelitis
7. Individuals inable to maintain seated or standing positions independently
8. Individuals who have severe spasticity (Modified Ashworth Scale grade ≥ 2)
9. Individuals who have bone metastases from cancer
10. Individuals who have severe internal diseases affecting device use (e.g., cardiovascular or respiratory diseases)
11. Individuals who have cognitive impairments preventing cooperation with device use
12. Individuals who have complaints of device-related side effects or potential rehabilitation discontinuation
13. Patients who are determined to be pregnant or potentially pregnant based on the medical interview
14. Individuals who have any other clinically significant findings deemed inappropriate by the investigator