Comparing effectiveness of 3-needle approach versus 5-needle approach of genicular nerve block on pain and quality of life in chronic osteoarthritis of knee: a double blinded randomised controlled trial.

Background: Knee osteoarthritis [KOA] is a common musculoskeletal disorder that is characterized by degeneration of the articular cartilage and the subchondral bone. It leads to pain and functional limitations in the joint. Genicular Nerve Blocks [GNB] or Genicular Nerve Radiofrequency Ablation [GNRFA] are pain-reducing procedures that can be used in such patients. Newer and more accurate anatomical landmarks for genicular nerves are being identified. More named genicular nerves are also being targeted for better pain relief.

Objectives: To compare the effectiveness of ultrasound-guided genicular nerve block using 3-point approach versus 5-point approach in patients of chronic knee Osteoarthritis on pain and quality of life.

Study Design: A double blinded randomized controlled trial.

Setting: Department of Physical Medicine and Rehabilitation [PMR], All India Institute of Medical Sciences [AIIMS], Jodhpur.

Methods: Patients satisfying the inclusion and exclusion criteria and provided consent were enrolled in the study and randomized into one of the two groups: GNB-CAT or GNB-RT. The patients underwent the procedure according to the allocated group, using a drug admixture of lidocaine and triamcinolone acetonide. The total dose of steroid used was constant in both groups. The patients were advised of a post-procedure rehabilitation protocol. Pain was assessed using an 11-point NRS, the functional status of the knee was evaluated using the TUG test duration and quality of life was assessed using the QoL component of the KOOS. The outcome measures were assessed at baseline, and 1 month and 3 months.

Results: A total of 180 patients, 90 in each group, were followed for 3 months. A reduction in pain and TUG test duration was noted at 1 and 3 months post-procedure in both groups. However, there was no significant difference between the two groups except that the patients who received GNB via the 5-nerve protocol reported a higher improvement in quality of life (58.54 ± 12.01 versus 54.02 ± 13.12, p-value = 0.011) after 3 months.

Limitations: A larger volume of injectate seeps through the cortices of long bones per injection site. This leads to the blockade of other smaller, unnamed nerves and non-neural pain generators around the knee joint.

Conclusions: The results revealed no significant difference between the groups; however, there was a considerable decrease in pain and TUG test durations within the groups. Consequently, neither strategy was better than the other. The group that received GNB via a 5-point method had a superior QoL-KOOS at three months following the procedure.

Trial Registration: This study was registered in the Clinical Trials Registry-India [CTRI/2023/06/054401] with registration date of 26/06/2023, after approval was obtained from the Institutional Ethics Committee, All India Institute of Medical Sciences, Jodhpur (Certificate Reference Number: AIIMS/EIC/2022/4201) with a date of 23/09/2022.