Genicular nerve ablation (GNA) is a non-surgical, minimally invasive treatment designed to alleviate persistent knee discomfort. This outpatient procedure uses radiofrequency energy to halt the transmission of pain signals from the knee joint to the brain. GNA offers an alternative for individuals whose chronic pain has not responded to more conventional therapies.
The Target: Understanding Genicular Nerves
The knee joint receives sensory information from a network of small nerves known as the genicular nerves. These branches run along the outside of the knee joint capsule and transmit pain signals originating from the joint itself. The targeted nerves typically include the superior medial, superior lateral, and inferior medial branches, which supply the majority of the joint’s front and sides. Blocking these specific nerves is an effective strategy for managing chronic knee pain caused by joint conditions like osteoarthritis or post-surgical discomfort. Since these nerves relay only sensory information, disrupting them relieves pain without impairing muscle function or movement of the leg.
Patient Qualification and Diagnostic Testing
Genicular nerve ablation is reserved for patients who have failed to find adequate relief from conservative methods. Before the full ablation, patients must undergo a mandatory diagnostic step called a genicular nerve block. During this test, a local anesthetic is temporarily injected near the targeted genicular nerves to numb them. The purpose of this temporary nerve block is to confirm that the genicular nerves are truly the primary source of the patient’s pain. To qualify for the procedure, the patient must report a significant, temporary reduction in knee pain (usually 50% or more) following the diagnostic injection. A positive response indicates that permanently disrupting these nerves will likely lead to sustained pain relief.
The Procedure: How Genicular Nerve Ablation Works
The ablation procedure begins with the patient positioned comfortably, and the physician applying a local anesthetic to numb the injection sites. Specialized X-ray guidance, called fluoroscopy, is used to precisely guide the placement of a thin, hollow needle (cannula) near the targeted genicular nerves. This imaging ensures the needle tip is accurately positioned adjacent to the nerve branches before proceeding.
Once the cannula is in place, a radiofrequency electrode is inserted through the needle and positioned at the nerve site. Radiofrequency ablation works by delivering a controlled electrical current through the electrode, which generates heat at the nerve tip. The temperature is typically raised to around 80 degrees Celsius for a brief period, creating a precise thermal lesion on the sensory nerve. This heat application effectively disrupts the nerve’s ability to transmit pain signals. The process is then repeated at each targeted nerve site.
Expectations and Recovery After Treatment
Following the radiofrequency ablation, patients may experience localized soreness or mild discomfort at the needle insertion sites for a few days. Most individuals are advised to take it easy for the remainder of the day and can typically resume their normal daily activities within 24 to 48 hours. Significant pain relief often begins to manifest within a few days to a couple of weeks as the treated nerves become fully inactive. The duration of pain relief is generally temporary because nerves naturally regenerate over time, typically lasting anywhere from six months to two years. Should the pain return after the nerves regenerate, the procedure can safely be repeated.