A cortisone shot, also known as a corticosteroid injection, is a common medical procedure used to deliver powerful anti-inflammatory medication directly into the knee joint to reduce pain and swelling, often caused by conditions like osteoarthritis. The question of whether the injection itself is painful is one of the most frequent concerns for patients considering this treatment. Understanding the specific sensations involved during the brief procedure and the temporary discomfort that can follow helps manage expectations.
The Immediate Sensation During the Injection
The injection process is quick, typically lasting less than a minute, and discomfort is minimized using medical techniques. A local anesthetic, such as lidocaine, is frequently applied or injected first, or mixed directly with the corticosteroid. This initial step might cause a brief, sharp sting or pinch, which quickly subsides as the numbing agent takes effect.
Once the area is numbed, the doctor guides the needle into the joint space. Patients often describe the sensation of the needle entering the joint as quick pressure or a dull push, rather than sharp pain. Injecting the medication mixture into the knee capsule creates a distinct feeling of fullness or pressure inside the joint, which is generally the most prominent sensation during delivery.
Many medical professionals now use image guidance, such as ultrasound or fluoroscopy, to ensure the needle is placed precisely into the intended area of inflammation within the joint. This real-time visualization increases the accuracy of the injection, reducing the need for multiple attempts and significantly lowering the chances of irritating surrounding structures like nerves or ligaments. This precision contributes to a more comfortable and safer experience for the patient.
Understanding Post-Injection Discomfort
Immediately following the procedure, the local anesthetic provides rapid, temporary pain relief that lasts for several hours. This initial comfort gives way to a common, sometimes unexpected, phenomenon known as a post-injection flare, or cortisone flare. This discomfort begins hours after the procedure, typically once the numbing medication has worn off.
The flare is a temporary inflammatory reaction caused by the body responding to the corticosteroid medication. The steroid is formulated as a suspension of microscopic crystals designed to dissolve slowly and provide long-term relief. However, the crystals themselves can irritate the joint lining before they fully disperse, leading to an increase in pain, swelling, and warmth in the knee, which is often worse than the original pain that prompted the injection.
The cortisone flare usually occurs within 12 to 24 hours of the injection and is self-limiting, resolving within 24 to 48 hours. This temporary escalation of symptoms is a normal side effect and indicates the medication was properly delivered into the joint space. The therapeutic benefit of the cortisone, which is the reduction of long-term inflammation, only begins to take effect after this temporary flare subsides.
Patients should be aware of the difference between the expected, moderate flare and signs of a rare, serious complication like infection. While the flare causes pain and swelling that peaks and then quickly improves, an infection causes severe, escalating pain and swelling. Infection is often accompanied by redness, warmth, and possibly a fever, requiring immediate medical attention if symptoms intensify dramatically beyond the 48-hour mark.
Practical Steps for Pain Mitigation and Recovery
Taking proactive steps before and after the injection can minimize both the immediate procedural discomfort and the temporary post-injection flare. Patients should openly discuss any anxiety or low pain tolerance with their provider before the procedure. This allows the provider to take extra measures, such as using a topical anesthetic spray or ensuring proper positioning to relax the muscles and reduce pressure during the injection.
Resting the knee joint is recommended for the first 24 to 48 hours following the procedure. This involves avoiding strenuous activity, heavy lifting, or prolonged periods of standing. Applying a cold pack or ice to the injection site for short intervals can help manage the localized pain and swelling associated with the cortisone flare.
To treat temporary pain, over-the-counter pain relievers such as acetaminophen are effective for managing the discomfort of the flare. Patients should avoid non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen unless specifically approved by the doctor, as their anti-inflammatory properties may interact with the corticosteroid. Patients are also advised to avoid submerging the knee in water for a couple of days to reduce the minimal risk of infection at the injection site.