Table 1.

Inclusion and exclusion criteria

Inclusion criteria

1. Has knee pain and is diagnosed with KOA (provide a relevant diagnosis certificate from a regular medical institution)

2. Accord with following (1) and two criteria from (2) or (3) or (4) or (5):

(1) Recurrent knee pain in the last month

(2) Narrowed joint space, subchondral cyst formation and bone sclerosis, or osteophytosis around joint margin on the radiographs in standing or load position in X-ray

(3) Aged 50 years and over

(4) Stiffness ≤ 30 min in the morning

(5) Palpable bone crepitation (fremitus) on movement of joint

3. Kellgren-Lawrence grade I–III of KOA

4. Be able to use smartphones with an Internet connection and send text messages

5. Be able to communicate in Mandarin and understand Chinese characters

Exclusion criteria

1. Diagnosed with rheumatoid arthritis, severe osteoporosis, or other pathological conditions of the knee joint

2. Knee replacement or other knee surgery

3. Receive rehabilitation treatment for KOA in hospitals, clinics, or rehabilitation institutions or participate in other projects related to KOA rehabilitation

4. Uncontrolled hypertension and diabetes (such as fasting blood glucose ≥ 16.7 mmol/L) or repeated episodes of hypoglycemia (blood glucose ≤ 3.9 mmol/L) or other diseases that restrict exercise (such as stroke, heart failure, and severe anemia)

5. Patients with a history of mental disorders

6. Being informed by a doctor that there are other circumstances in which it is inappropriate to exercise without supervision

7. Unable to sign informed consent

8. Unable to communicate with others in normal Chinese

9. Cannot use smartphone or WeChat to send messages and have video calls