Coolief: Genicular Nerve Block & RF Neurotomy of Knee Joint

Chronic osteoarthritis pain of the knee is often not effectively managed with non-pharmacological or pharmacological treatments. Radiofrequency (RF) neurotomy (Coolief), when applied to articular nerve branches (genicular nerves), provides a therapeutic alternative for effective management of chronic pain associated with osteoarthritis of the knee.


Chronic knee pain secondary to osteoarthritis
Failed knee replacement
Unfit for knee replacement
Want to avoid surgery

Although surgery is generally effective for patients with advanced disease, some older individuals with comorbidities may not be appropriate surgical candidates. In addition some patients do not wish to consider surgery and prefer non- surgical options. In these patients, radiofrequency (RF) neurotomy of the genicular nerves might be a successful alternative to surgery. This procedure is based on the theory that cutting the nerve supply to a painful structure may alleviate pain and restore function.

At Pain Spa Dr Krishna is very experienced in performing interventional pain procedures. In December 2013, Dr Krishna became the first clinician in the UK to perform cooled radiofrequency treatment (Coolief) of the knee joint.


The knee joint is innervated by the articular branches of various nerves, including the femoral, common peroneal, saphenous, tibial and obturator nerves. These articular branches around the knee joint are known as genicular nerves. Genicular nerves can be easily approached percutaneously under fluoroscopic guidance.

Genicular branches of the knee joint

Genicular nerves consist of the superior lateral (SL), middle, superior medial (SM), inferior lateral (IL), inferior medial (IM), and recurrent tibial genicular nerve . The targets included the SL, SM and IM genicular nerves which pass periosteal areas connecting the shaft of the femur to bilateral epicondyles and the shaft of the tibia to the medial epicondyle.

Although genicular nerves are the main innervating articular branches for the knee joint, other articular branches may also be present. For this reason, pain of the knee joint may not be completely relieved, resulting in poor response to radiofrequency neurotomy.

Diagnostic genicular nerve blocks

These injections are performed under fluoroscopy guidance. A small amount of local anaesthetic (1-2ml) of lidocaine or bupivacaine is injected around the superior lateral (SL), superior medial (SM) and the inferior medial (IM) branches. A response is considered positive if there is at least 50% reduction in pain in the 24hrs following injection.

Cooled radiofrequency of genicular nerves (Coolief)

Patients with a positive response are offered either cooled (Coolief) or conventional radiofrequency neurotomy for a more sustained response. The procedure is usually done on an outpatient basis. The procedure is performed under fluoroscopic guidance to ensure accuracy of needle placement. Patients need to be aware that the outcome of the procedure is variable and they may not receive the desired benefits. Similarly, they must be aware of the transient nature of the therapeutic benefits and that there may need repeated injections.

Radiofrequency treatment is a two-step procedure. The first step is diagnostic, involving injection of local anaesthetic around the genicular branches innervating the knee joint, as described above. Patients who experience good pain relief following diagnostic injections are offered radiofrequency denervation treatment. This involves creating a heat lesion around the genicular nerves carrying painful impulses from the knee joint. Successful treatment can result in pain relief lasting several months.

Either conventional radiofrequency treatment (70-80°c) or cooled radiofrequency treatment (60°c) can be used. Cooled radiofrequency (Coolief) allows creation of larger-volume, spherical lesions compared to conventional radiofrequency.

Treatment is performed under local anaesthetic and can take 4 to 6 weeks to work.


Complications are rare, particularly if injections are performed using a precise needle-positioning technique. Septic arthritis can be avoided with appropriate aseptic precautions. Severe allergic reactions to local anaesthetics are uncommon. Post-procedural pain flare-up is not uncommon, and may be treated with painkillers. Neurological complications including paraesthesias and numbness have been described but are extremely rare. Radiofrequency treatment can cause patchy numbness of the over lying skin. Incidence of infection is low as the procedure is performed under strict aseptic conditions and the injections are extra articular.


Genicular nerve block is an innovative procedure that can be of diagnostic benefit in patients with chronic knee pain. Cooled radiofrequency neurotomy (COOLIEF) of the genicular nerves can provide sustained pain relief in these patients. This technique provides an alternative treatment option to patients who cannot or do not wish to undergo surgical treatments including joint replacement surgery. However, it is important to note that in some cases injection treatment may not provide the desired results or the pain relief may not be sustained. At Pain Spa Dr Krishna is very experienced in performing interventional pain procedures. In December 2013, Dr Krishna became the first clinician in the UK to perform cooled radiofrequency treatment of the knee joint.

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