This is a pilot diagnostic accuracy study conducted to assess the diagnostic ability of a novel APD for auricular point detection among patients with knee osteoarthritis (KOA), as compared with an already commercialized device.

The present study is a pilot diagnostic accuracy study conducted to assess the diagnostic ability of a novel APD for auricular point detection among patients with knee osteoarthritis, as compared with an already commercialized device. The investigators will test if the novel APD could provide a more reliable and quantifiable diagnosis than traditional devices currently available in the market; They will also use the APD device to test whether the cutaneous electrical impedance detected from the corresponding auricular points by the novel device is the lowest in the knee and lower limb area in the KOA population. As a pilot study, 12 patients with KOA will be recruited from the Department of Anesthesiology, Queen Mary Hospital, the University of Hong Kong. 12 healthy subjects will be recruited from the university community. Auricular acupoint detection will be accomplished with the new device and a control device. The electrical impedance will be measured and recorded. Patient's condition will also be evaluated by the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). The specificity and sensitivity of the auricular point detection by the APD device will be calculated. Cohen's kappa coefficient (κ) will be used to test the inter-methods reliability, test-retest reliability, and inter-tester reliability. Moreover, the Pearson Correlation Coefficient will be used to test the correlation between the electrical impedance of the auricular point of knee and the KOOS score and WOMAC score.

Inclusion Criteria:

• Average daily knee pain >=5 point measured by a 10-point VAS scale;
• Diagnosed KOA of any reason;
• The different patient categories;
• Patients with knee osteoarthritis enrolled for knee arthroplasty, osteotomies around the knee, cartilage repair, or anterior cruciate ligament-deficient knees enrolled for anterior cruciate ligament reconstruction;
• Surgical plan in the coming month after inclusion;
• Provide written inform consent;
• Free of any other diagnosed psychological conditions;

Exclusion Criteria:

• with any other diseases such as cardiovascular, renal, neurological, digestive, hepatic, respiratory disease;
• Pregnancy or lactation;
• Participation in a clinical study that may interfere with participation in this study;
• History of or current tobacco, alcohol use;
• Anything that would place the individual at increased risk or preclude the individual's full compliance with or completion of the study;
• Unable to provide written informed consent due to any reason;

KOA patients with surgical schedule will be referred to this study by an anesthesiologist from the inpatient or outpatient unit of the Department of Anesthesiology Queen Mary Hospital.

The IPD sharing depends on the discretion of participants and principal investigator.