The ultrasound-guided genicular nerve block was performed at the site of the superior lateral, the superior medial, and the inferior medial genicular nerves. Color Doppler was used to identify the arterial structures which serve as landmarks for the corresponding nerves.10 cm 21 G insulated block needle was inserted and aligned with the ultrasound scanning plane. Once satisfactory position of the needle is confirmed, 6 mL of a solution containing 6 mL of 2% lidocaine or 6 mL dextrose or 6 mL saline was slowly injected. Spread of local anesthetic was documented adjacent to the target nerve. This procedure was performed at the site of the three genicular nerves Interventions: Drug: 6 mL 2% lidocaine Procedure: Genicular nerve block

The ultrasound-guided genicular nerve block was performed at the site of the superior lateral, the superior medial, and the inferior medial genicular nerves. Color Doppler was used to identify the arterial structures which serve as landmarks for the corresponding nerves.

10 cm 21 G insulated block needle was inserted and aligned with the ultrasound scanning plane. Once satisfactory position of the needle time is confirmed, 5 mL of a saline was slowly injected. Spread of local anesthetic was documented adjacent to the target nerve. This procedure was performed at the site of the three genicular nerves.

Interventions:Drug: Saline Procedure: Genicular nerve block

The ultrasound-guided genicular nerve block was performed at the site of the superior lateral, the superior medial, and the inferior medial genicular nerves. Color Doppler was used to identify the arterial structures which serve as landmarks for the corresponding nerves.

10 cm 21 G insulated block needle was inserted and aligned with the ultrasound scanning plane. Once satisfactory position of the needle time is confirmed, 5 mL of a dextrose was slowly injected. Spread of local anesthetic was documented adjacent to the target nerve. This procedure was performed at the site of the three genicular nerves.

Interventions:Drug: Dextrose Procedure: Genicular nerve block

The color doppler ultrasound-guided genicular nerve block at the site of the superior lateral, the superior medial, and the inferior medial genicular nerves.

Neuropathic pain reduction is measured by painDETECT questionnaire (PD-Q) which consists of 9 items that evaluate pain quality, pattern and radiation. Possible scores range from -1 to 38, with higher scores indicating more neuropathic-like symptoms. Clinical assessments:score ≤12: unlikely neuropathic pain; score 13-18: possibly neuropathic pain, and score ≥19:likely neuropathic pain.

Nociceptive pain reduction is measured by Visual analogue scales (VAS). The score is determined by measuring the distance (mm) on the 10-cm line between the "no pain" anchor and the patient's mark, providing a range of scores from 0-100. A higher score indicates greater pain intensity. Pain intensity as none, mild, moderate, or severe, the following cut points on the pain VAS have been recommended: no pain (0-4 mm), mild pain (5-44 mm), moderate pain (45-74 mm), and severe pain (75- 100 mm).

Physical functional disability is measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). The WOMAC index is a self-administered health questionnaire specifically designed for patients with osteoarthritis of the hip or knee. It consists of 24 multiple-choice items grouped into 3 categories: WOMAC pain, WOMAC stiffness, and WOMAC physical function. The questions are ranked on a 5-point Likert scale (1 point, best result; 5 points, worst result), and the scores are added up for each category. The WOMAC scores from 1 (best) to 5 (worst) points to a system of 0 (worst) to 100 (best) points.