Cortisone Shot for Knee Pain: What to Expect, How Long It Lasts & When It Helps

If chronic knee pain is limiting your daily activities and you're looking for relief that doesn't require surgery, a cortisone shot may be an effective option. These powerful anti-inflammatory injections can provide significant pain relief for weeks to months, allowing you to participate in physical therapy, delay surgery, or simply regain mobility for activities you've been avoiding.

The short answer: A cortisone shot for knee pain typically provides relief within 3-7 days and can last anywhere from 6 weeks to 6 months, depending on the severity of your arthritis and inflammation. The injection works by reducing inflammation in the knee joint, which decreases pain and swelling. Most patients experience meaningful improvement, though results vary based on individual factors.

This guide will explain how cortisone injections work, what to expect during and after the procedure, how long relief typically lasts, and when this treatment is most effective compared to other options.

A cortisone shot is an injection of corticosteroid medication directly into the knee joint. Corticosteroids are synthetic versions of hormones your body naturally produces to reduce inflammation. When injected into an inflamed joint, they provide powerful and targeted anti-inflammatory relief.

Common corticosteroid medications used for knee injections include:

• Methylprednisolone (Depo-Medrol)

• Triamcinolone (Kenalog)

• Betamethasone (Celestone)

• Dexamethasone (Decadron)

These medications are often mixed with a local anesthetic like lidocaine to provide immediate numbing relief while the corticosteroid takes effect over the following days.

Cortisone shots are one of several orthopedic injection options available for knee pain. Other injection types include hyaluronic acid (gel injections) and platelet-rich plasma (PRP), which work through different mechanisms and may be recommended depending on your specific condition.

When you have knee arthritis or inflammation, your body's immune system releases chemicals that cause swelling, pain, and joint damage. Cortisone works by suppressing this inflammatory response.

Specifically, cortisone injections:

• Reduce inflammation in the joint lining (synovium)

• Decrease swelling that causes stiffness and limited range of motion

• Block pain signals by reducing inflammatory chemicals that activate pain receptors

• Improve joint function by reducing the mechanical friction caused by swelling

The result is significant pain relief that allows many patients to return to activities they've been avoiding, participate more effectively in physical therapy, or delay surgical intervention.

Cortisone injections are most effective for knee conditions involving inflammation rather than mechanical damage. Your orthopedic specialist may recommend a cortisone shot if you have:

Osteoarthritis: The most common reason for knee cortisone injections. When cartilage breaks down, the joint becomes inflamed and painful. Cortisone reduces this inflammatory response.

Rheumatoid arthritis: An autoimmune condition that causes significant joint inflammation. Cortisone can provide temporary relief during flare-ups.

Bursitis: Inflammation of the fluid-filled sacs (bursae) that cushion the knee joint. Knee bursitis responds well to cortisone injections.

Tendonitis: Inflammation of tendons around the knee, though cortisone is used cautiously in tendon areas due to potential weakening effects.

Post-injury inflammation: Swelling and inflammation following knee injuries, sprains, or minor trauma.

Synovitis: Inflammation of the joint lining, which can occur independently or alongside arthritis.

Cortisone shots are less effective for purely mechanical problems like meniscus tears, ligament injuries, or advanced bone-on-bone arthritis where little cartilage remains. In these cases, other treatments or surgical intervention may be more appropriate.

Cortisone injections are performed in the office and take only a few minutes. Here's what the process typically involves:

The timeline for cortisone relief varies, but most patients follow a predictable pattern:

First 24-48 hours: You may experience immediate but temporary relief from the local anesthetic mixed with the cortisone. Some patients also notice increased pain or swelling during the first 1-2 days as the cortisone begins working. This is called a "cortisone flare" and occurs in about 10-15% of patients.

Days 3-7: The cortisone begins to take full effect. Most patients notice meaningful pain reduction and improved mobility during this period.

Weeks 2-4: Maximum benefit is typically reached. Pain and stiffness should be significantly reduced compared to pre-injection levels.

Weeks 6-24: Relief gradually diminishes as the medication wears off. How long the benefit lasts varies considerably among patients.

If you don't experience noticeable improvement within 2 weeks, the injection likely isn't providing the expected benefit, and alternative treatments should be discussed.

This is one of the most common questions patients ask, and the answer varies based on several factors.

Typical duration:

• Most patients: 6-12 weeks of meaningful relief

• Best responders: 3-6 months of relief

• Limited responders: 2-4 weeks of relief

Factors that affect how long relief lasts:

Severity of arthritis: Patients with mild to moderate arthritis typically experience longer-lasting relief than those with advanced bone-on-bone changes.

Underlying cause: Inflammatory conditions like rheumatoid arthritis or bursitis may respond better than degenerative osteoarthritis.

Activity level: Remaining active within appropriate limits can help maintain benefits, while overuse may shorten relief duration.

Previous injections: Some patients find that repeated injections provide diminishing returns, with shorter relief periods over time.

Body's metabolic rate: How quickly your body breaks down the medication affects duration.

Injection technique: Precise placement into the joint space (rather than surrounding soft tissue) provides better and longer-lasting results.

Your orthopedic surgeon can give you a more specific estimate based on your imaging, arthritis severity, and individual factors.

Proper aftercare helps maximize the injection's effectiveness and reduces the risk of complications.

First 24-48 hours:

• Rest the knee and avoid strenuous activities

• Apply ice if you experience swelling or discomfort (15-20 minutes several times daily)

• Avoid weight-bearing exercise like running, jumping, or prolonged standing

• Take over-the-counter pain relievers if needed for post-injection discomfort (acetaminophen is preferred; check with your doctor about NSAIDs)

Days 3-7:

• Gradually resume normal activities as pain allows

• Avoid high-impact activities that stress the knee

• Start or continue physical therapy if recommended, as reduced pain allows for more effective exercise

Ongoing:

• Maintain a healthy weight to reduce knee stress

• Continue low-impact exercise like swimming, cycling, or walking to maintain joint health

• Avoid activities that repeatedly stress the knee until your doctor clears you

Warning signs to report to your doctor:

• Severe or worsening pain after 48 hours

• Significant swelling, redness, or warmth around the knee

• Fever or chills (signs of possible infection)

• Inability to bear weight on the leg

Serious complications from cortisone injections are rare but require immediate medical attention if they occur.

When appropriately used, cortisone injections offer several advantages:

Fast relief: Most patients experience meaningful improvement within a week, much faster than oral medications or physical therapy alone.

Targeted treatment: The medication goes directly to the source of inflammation rather than circulating through your entire body.

Avoids systemic side effects: Unlike oral corticosteroids, knee injections produce minimal whole-body effects.

Enables physical therapy: Pain reduction allows you to participate more effectively in rehabilitation exercises.

Non-surgical option: Provides an alternative or bridge to surgery for patients who aren't ready for or don't need surgical intervention.

Improves function: Reduced pain often translates to better mobility and ability to perform daily activities.

Diagnostic value: If a cortisone shot provides significant relief, it confirms that inflammation is a major contributor to your pain, helping guide treatment planning.

Cortisone injections are generally safe, but like any medical procedure, they carry some risks:

Common side effects (10-15% of patients):

• Cortisone flare: Temporary increase in pain and swelling for 1-2 days after injection

• Skin discoloration or thinning at the injection site (more common in darker skin tones)

• Facial flushing or warmth for a few hours after injection

Uncommon side effects (1-5% of patients):

• Temporary elevation in blood sugar (important for diabetic patients to monitor)

• Temporary increase in blood pressure

• Insomnia or mood changes for a few days

Rare complications (<1% of patients):

• Joint infection (septic arthritis) - very rare but serious

• Allergic reaction to the medication

• Tendon weakening or rupture if injected near tendons repeatedly

• Cartilage damage from frequent, repeated injections

Long-term considerations:

Most orthopedic surgeons limit cortisone injections to 3-4 per year in the same joint to minimize the risk of cartilage damage, tendon weakening, and bone loss.

Your doctor will weigh these risks against the benefits based on your specific situation, overall health, and treatment goals.

Cortisone injections work best in specific situations:

Ideal candidates:

• Patients with mild to moderate knee arthritis with inflammatory flare-ups

• Those who have tried conservative treatments (rest, ice, physical therapy) with partial improvement

• Patients who need temporary relief to participate in physical therapy or rehabilitation

• Individuals who want to delay surgery timing for personal or medical reasons

• Those experiencing bursitis or inflammatory conditions rather than purely mechanical damage

Less effective scenarios:

• Advanced bone-on-bone arthritis with minimal cartilage remaining

• Mechanical problems like meniscus tears or ligament injuries requiring surgical repair

• Patients who require repeated injections every 4-6 weeks (suggests more definitive treatment is needed)

• Conditions where structural damage is the primary problem rather than inflammation

If you've had multiple cortisone shots with diminishing returns, it may be time to discuss other treatment options, including surgery.

Cortisone isn't the only injection therapy for knee pain. Understanding the alternatives helps you make informed decisions.

Hyaluronic acid (gel) injections:

• Provide lubrication and cushioning rather than reducing inflammation

• Typically given as a series of 1-3 injections over several weeks

• May last 3-6 months when effective

• Best for mild to moderate osteoarthritis

• Don't carry the same cartilage or tendon concerns as cortisone

Platelet-rich plasma (PRP):

• Uses concentrated platelets from your own blood to promote healing

• May provide longer-lasting relief (6-12 months when effective)

• Results are more variable than cortisone

• Typically not covered by insurance

• Considered an emerging therapy with ongoing research

Stem cell injections:

• Aim to regenerate damaged tissue

• Results highly variable and not yet proven superior to established treatments

• Expensive and typically not covered by insurance

• Still investigational

Your orthopedic surgeon can help you determine which injection type is most appropriate based on your specific condition, arthritis severity, and treatment goals. Some patients benefit from trying cortisone first, then moving to alternative injections if relief is inadequate or too short-lived.

There's no absolute limit on cortisone injections, but most orthopedic surgeons follow evidence-based guidelines to minimize risks:

General recommendations:

• Maximum 3-4 injections per year in the same joint

• Minimum 6-8 weeks between injections to assess effectiveness and reduce cumulative effects

• Consider alternative treatments if you need more frequent injections for relief

Why these limits exist:

Repeated cortisone exposure can potentially weaken tendons, damage cartilage, and accelerate joint degeneration. While occasional injections are safe and beneficial, using them as a long-term maintenance strategy isn't ideal.

What it means if you need frequent injections:

If cortisone shots provide only 4-6 weeks of relief and you find yourself requesting injections every other month, this suggests your arthritis has progressed to a point where more definitive treatment may be appropriate.

This could include exploring total knee replacement, partial knee replacement, or other surgical interventions that address the underlying joint damage rather than temporarily managing inflammation.

Before proceeding with a cortisone injection, ask your orthopedic specialist these important questions:

About the procedure:

• "Is cortisone injection the best option for my specific condition?"

• "How many injections do you recommend, and how far apart?"

• "Will you use ultrasound guidance for precise placement?"

About expected outcomes:

• "What percentage of your patients with my condition experience meaningful relief?"

• "How long does relief typically last for someone with my arthritis severity?"

• "What should I do if the injection doesn't provide adequate improvement?"

About alternatives:

• "Should I try other injection types like hyaluronic acid or PRP?"

• "What conservative treatments should I continue alongside injections?"

• "At what point would you recommend considering surgery?"

About aftercare:

• "What activities should I avoid after the injection?"

• "When can I resume exercise or physical therapy?"

• "What warning signs should prompt me to call your office?"

Having these discussions ensures you have realistic expectations and understand your complete range of treatment options.

If you're experiencing chronic knee pain and want to explore whether a cortisone injection or other orthopedic injection therapy is right for you, the first step is scheduling an evaluation with a board-certified orthopedic specialist.

Mountain Spine & Orthopedics offers:

• Same-day injection appointments when appropriate

• Same-day and next-day consultations to avoid long wait times

• Free MRI review to assess knee damage before your visit

• Comprehensive treatment options including all injection types, physical therapy coordination, and surgical expertise when conservative measures aren't enough

• Multi-state access with convenient locations across Florida, New Jersey, New York, and Pennsylvania

Book an appointment today to discuss whether cortisone injection is appropriate for your knee pain, or request a candidacy check to determine which treatment approach is best for your specific condition.