Knee Ablation: Side Effects, Risks, and Long-Term Considerations

What are the side effects of a knee ablation?

Knee ablation, specifically radiofrequency ablation (RFA) of the genicular nerves, is a procedure used to alleviate chronic knee pain, primarily from osteoarthritis, by disrupting nerve signals. While generally considered safe and effective for many, it carries a range of potential side effects, from common mild discomforts to rare but more serious complications, which patients should thoroughly discuss with their healthcare provider.

Understanding Knee Ablation (Radiofrequency Ablation)

Knee ablation, more formally known as genicular nerve radiofrequency ablation (RFA), is a minimally invasive procedure designed to provide long-term pain relief for chronic knee pain, particularly in individuals who are not candidates for surgery or have not found relief from other treatments. It targets the genicular nerves—small sensory nerves that transmit pain signals from the knee joint to the brain.

• What it is: RFA uses heat generated by radiofrequency waves to create a small lesion on these genicular nerves. This lesion disrupts their ability to send pain signals, effectively "turning down the volume" on knee pain.
• Purpose: The primary goal is to reduce chronic knee pain, improve function, and enhance the quality of life, often for conditions like osteoarthritis, chronic post-surgical knee pain, or patellofemoral pain syndrome.
• How it works: Under local anesthetic and often light sedation, a thin needle is guided to specific genicular nerves around the knee using fluoroscopy (X-ray guidance). Once confirmed, a small electrical current is passed through the needle, heating the tip and creating a controlled lesion on the nerve.

Common and Expected Side Effects

Following a knee ablation procedure, some side effects are common and generally mild, resolving within a few days to weeks.

• Pain or Discomfort at the Injection Site: It is normal to experience localized soreness, tenderness, or a dull ache at the sites where the needles were inserted. This is typically managed with over-the-counter pain relievers or ice packs.
• Bruising and Swelling: Minor bruising and swelling around the injection areas are common. This is a normal response to needle insertion and usually subsides within a week.
• Numbness or Altered Sensation: Because the procedure targets sensory nerves, temporary numbness, tingling, or an altered sensation in the skin around the knee is a common side effect. This usually resolves as the nerves regenerate, which can take several weeks to months. In some cases, a small patch of permanent numbness may remain.
• Temporary Weakness: Although RFA targets sensory nerves, there can be a temporary, mild motor weakness or feeling of instability, especially if motor nerve branches are inadvertently affected. This is typically short-lived.

Less Common but More Serious Side Effects

While rare, more significant complications can occur. Awareness of these is crucial for patient safety and prompt intervention if they arise.

• Infection: As with any invasive procedure, there is a small risk of infection at the injection sites. Symptoms include increased pain, redness, warmth, swelling, and pus discharge.
• Nerve Damage: While the goal is to lesion specific sensory nerves, there's a rare risk of damage to adjacent motor nerves, leading to prolonged weakness, or to other sensory nerves, causing persistent or new areas of numbness or neuropathic pain (nerve pain).
• Skin Burns: Though rare with proper technique and real-time temperature monitoring, the radiofrequency probe can cause superficial skin burns if not positioned correctly.
• Increased Pain (Post-Ablation Flare): Some individuals experience a temporary increase in knee pain, often described as a "flare-up," in the days or weeks following the procedure. This is thought to be an inflammatory response to the nerve lesioning and typically resolves.
• Bleeding: While generally minimal, there's a small risk of more significant bleeding or hematoma formation, especially in individuals on blood-thinning medications.
• Allergic Reaction: Rarely, a patient may have an allergic reaction to the local anesthetic or other medications used during the procedure.

Potential Long-Term Considerations

The long-term effects and durability of knee ablation are subjects of ongoing research.

• Durability of Pain Relief: The relief from knee ablation is not permanent, as nerves can regenerate. Pain relief typically lasts anywhere from 6 to 18 months, varying significantly among individuals. Some may experience longer relief, while others may find it shorter.
• Effect on Joint Health: Current evidence suggests that genicular nerve RFA does not directly impact the progression of underlying joint conditions like osteoarthritis. It manages the pain signals but does not repair joint damage.
• Repeat Procedures: Due to nerve regeneration, repeat ablations may be necessary to maintain pain relief. The long-term safety and efficacy of multiple repeated procedures are still being evaluated.

When to Seek Medical Attention

It is important to contact your healthcare provider immediately if you experience any of the following symptoms after a knee ablation:

• Fever or chills.
• Severe or worsening pain that is not relieved by medication.
• Spreading redness, warmth, or pus discharge from the injection sites.
• Significant or increasing swelling in the knee or leg.
• New or worsening weakness, numbness, or tingling that is severe or interferes with daily activities.
• Any signs of an allergic reaction, such as rash, hives, difficulty breathing, or swelling of the face or throat.

Pre-Procedure Discussion with Your Physician

Before undergoing a knee ablation, a thorough discussion with your physician is essential. This conversation should cover:

• Risk-Benefit Analysis: A personalized assessment of whether the potential benefits of pain relief outweigh the risks of side effects for your specific condition and health status.
• Alternative Treatments: A review of other available treatment options for your knee pain, including physical therapy, medication, injections, and surgical interventions.
• Personalized Risk Factors: Discussion of any personal health conditions (e.g., bleeding disorders, diabetes, allergies) or medications you are taking that might increase your risk of complications.

By understanding the potential side effects and engaging in open communication with your healthcare team, you can make an informed decision about whether knee ablation is the right treatment option for managing your chronic knee pain.