This is a randomized controlled trial comparing the short-term and medium-term effect of self-administered and knee health education for relieving knee pain in middle-aged and older adults with knee osteoarthritis.

Knee osteoarthritis (OA) is one of the major causes of physical disability commonly influencing people aged above 50 years. Acupressure is proposed for alleviating knee OA symptoms because of the low cost of intervention, accessibility, and safety.

Objectives: 1. To examine the short- and medium-term effectiveness of self-administered acupressure taught by a short training course on relieving knee OA pain in middle-aged and older adults. And to evaluate the subjects' compliance with self-administered acupressure for knee OA.

Hypothesis: self-administered acupressure group would have a greater pain relief compared to the knee health education control in subjects with knee OA at week 4 (short-term) and 12 (medium-term).

Design and subjects: A randomized, parallel-group, control trial. 314 subjects with knee OA will be recruited; 157 per group. All eligible subjects will be randomized to either self-administered acupressure or knee health education control group in 1:1 ratio.

Interventions: Subjects in the self-acupressure group will attend two 2-hour training sessions to learn self-acupressure and will practice self-acupressure twice a day for 12 weeks; subjects in the education control group will receive two 2-hour training sessions to learn the health information related to knee OA. They will be told to follow the knee health instructions for 12 weeks.

Main outcome measures: The primary outcome measure is the numerical rating scale for knee pain. Other measures include Western Ontario and McMaster University Osteoarthritis Index (WOMAC), Short-Form Six-Dimension (SF-6D), Timed Up & Go Test (TUG) and Fast Gait Speed (FGS). Acceptability of two training courses will also be evaluated.

Data Analysis: Differences in the questionnaire scores will be examined using a linear mixed-effects model. Intention-to-treat analyses will be conducted. Effect sizes will be computed by dividing the difference in means by the pooled standard deviation. Incremental costs and incremental effects will be compared between the self-acupressure and knee health education groups and and plotted the results in a cost-effectiveness acceptability curve.

Inclusion Criteria:

• ethnic Chinese;
• aged 50 years or above;
• ability to comprehend Chinese;
• fulfilling any 3 of the following criteria: i. morning stiffness ≤ 30 min; ii. crepitus on active joint motion; iii. bone tenderness; iv. bone enlargement; or v. no palpable joint warmth (This classification yielded 84% sensitivity and 89% specificity for OA knee diagnosis);
• having knee pain for at least 3 months;
• Knee pain ≥3 on a Likert pain scale from 1-10;
• having a smartphone (or a family member living together having a smartphone) that is compatible to WhatsApp (it is the investigator's experience in the pilot study that most of every subject had been used to using WhatsApp for social communication);
• willing to provide informed consent

Exclusion Criteria:

• medical diagnoses or conditions that preclude individuals from active participation (e.g. bleeding disorders, alcohol or drug abuse);
• knee pain related to other conditions (cancer, fracture, rheumatoid arthritis, rheumatism) as screened according to the red flags for further investigation or referral in the NICE 2014 Guidelines for Osteoarthritis of the knee;
• score < 22 in Hong Kong Montreal Cognitive Assessment (HK-MoCA) indicating cognitive impairment that may prevent understanding of training instructions;
• body mass index over 30, the obese II criteria for Asians (it will be too difficult for the obese subjects to perform acupressure on the acupoints as physical pressure reaching the muscle is required);
• presence of skin lesions or infections at the treatment sites;
• ever had knee replacement surgery;
• pregnancy or contemplating pregnancy;
• ever received acupressure or steroid injection for knee pain over the past 6 months