Knee pain is so common in patients with OPD that every second elderly patient complains about it. Recently, studies have successfully demonstrated that local nerve block as an OPD procedure can give patients instant relief. Much useful for all general practitioners.

A randomised study revealed that blocking drugs administered to the genicular nerves around the knee significantly decreased osteoarthritis patients' sensations of pain, considerably more so than placebo injections. Newly published research in Arthritis & Rheumatology found that at week 4 after injections, patients in the nerve block group reported mean decreases in pain levels of 3.0 points from baseline on a standard 10-point scale, compared to an average drop of 0.2% among those allocated placebo.

By week 8, however, the efficacy had definitely started to wane, with average pain levels in the nerve block group increasing by 0.7 points from week 4. At week 12, the mean scores had grown by an additional 0.7 points and no longer varied significantly from those of the placebo group.

For the randomised study, 64 patients were randomly allocated to undergo nerve blocks or a placebo in a single session. The blocking drugs utilised were celestone chronodose and bupivacaine, injected into close to three nerves surrounding the knee: the superolateral, supermedial, and inferomedial genicular nerves. Ultrasound was used to find them for exact implantation. The placebo group got subcutaneous injections of saline at the identical areas on the skin's surface, but without nerve penetration. Patients were permitted to continue using their regular painkillers as required.

The pain was evaluated with visual analogue scales. The Western Ontario-McMaster Universities Osteoarthritis Index (WOMAC) method measured pain, stiffness, and impairment in distinct categories and as a total score to assess the severity of osteoarthritis.

The average age of patients in the nerve block group was around 70, whereas those in the placebo group were 66. Just over half of the former were female, whereas two-thirds of the placebo group were female. In the nerve block group, baseline pain levels were 6.3% higher than in the placebo group.

All of the primary outcome measures, including WOMAC scores, followed the same pattern: the nerve block group saw dramatic improvements in their initial post-injection assessment at week 2, which were sustained through week 4. Each test score thereafter started to revert to its initial level. During the course of the trial, the placebo group exhibited little change in any measurable characteristic.

In general, however, the future of nerve block as a treatment for osteoarthritis is promising. "At the conclusion of the research, several patients sought further [treatments]. Based on our results, we feel that offering this intervention is appropriate "the authors stated. The nerve blocks looked both safe and efficient. There were no problems detected during operations or during the following clinic visits. Limitations included the limited sample size and the chance that patients may distinguish between treatments (clinicians giving the injections obviously were not blinded).

How the nerve block is performed?

Ultrasound anatomy of the genicular nerves demonstrating needle insertion and local anaesthetic distribution. SMGN, superomedial genicular nerve, and artery; ILGN, inferolateral genicular nerve, and artery; IMGN, inferomedial genicular nerve, and artery.

Using either an in-plane or out-of-plane method, the needle tip is advanced until bone contact is felt until the injection site has been determined. Alternately, the needlepoint may be guided toward the bone surface by rotating the transducer in a transverse direction. The LA is injected after establishing the precise place.

Inactivating nerves by radiofrequency ablation

Radiofrequency (RF) ablation does not just numb nerves. It releases heat that destroys the outside of neurons, preventing them from transmitting a pain signal.

Similar to genicular nerve blocks, the technique is performed as an outpatient operation. It includes inserting a needle whose tip is heated to 176 degrees Fahrenheit. Using ultrasound or X-ray guidance guarantees that the needle is inserted directly into the nerve. The use of an insulated needle prevents nearby tissues from being burned or overheated.

The heat from the needle's tip induces inflammation, which assists in immobilising the nerve. Additionally, it might produce transient pain and oedema at the injection site. The majority of people have relief five to seven days after the pain and swelling reduce, however, some individuals experience relief immediately. RF ablation often gives pain relief for six to twelve months. Pain may return because injured nerves repair and renew over time, but underlying arthritis continues. Thereafter, the technique may be repeated.

RF ablation is not effective for everyone. The infusion of the anaesthetic for the nerve block determines whether RF ablation is likely to be successful. If the anaesthetic eased the pain by at least 50%, even temporarily, RF may be worth a try. If there is no favourable response to the medicine, your physician will likely not proceed to RF ablation.

Recognising possible concerns

When inserting a needle into the body, there are inherent hazards. The possible consequences of a nerve block and RF ablation include bleeding, infection, and injury to surrounding tissues. But they are uncommon.

Using tiny needles reduces the danger of bleeding for physicians. Infection is rare since the surgery is performed in a sterile environment. By employing X-ray imaging or ultrasound, damage to other structures is reduced.

Function enhancement is the final aim

The objective is to enable individuals to be more active and involved. If we can reduce someone's suffering, we've done a good job; if we can increase their function, we've done an excellent one.

These methods do not exclude any other therapeutic alternatives. If genicular nerve blocks or RF ablation fail, joint replacement surgery is still an option. Some individuals select a nerve block for pain management while postponing surgery for various reasons.

Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article: Dr Monish Raut is a practising super specialist from New Delhi.