Cortisone Shot for Knee Pain: How It Works and What to Expect

What is a cortisone injection and what does it contain?

A cortisone shot for the knee is an intraarticular injection — meaning the medication is placed inside the joint space. It typically contains two components:

1. A corticosteroid (such as methylprednisolone, triamcinolone, or betamethasone) — the anti-inflammatory agent 2. A local anesthetic (such as lidocaine or bupivacaine) — which provides immediate but short-lived pain relief and helps confirm correct placement

The word "cortisone" is commonly used, but the medications used today are synthetic corticosteroids with more predictable effects than cortisone itself.

The injection is usually performed in an office or clinic setting, taking only a few minutes. Ultrasound or fluoroscopy (X-ray guidance) is sometimes used to confirm accurate needle placement, particularly when anatomy makes the joint harder to access.

What conditions is a cortisone knee injection used for?

Corticosteroid injections are used for knee conditions where inflammation is the primary driver of pain:

• Knee osteoarthritis (OA): The most common indication. Pain from OA often has an inflammatory component alongside cartilage loss. Current guidelines from AAOS and OARSI note that intraarticular corticosteroids can provide short-term pain relief in knee OA, though they do not slow disease progression 1Ref 1Brophy RH, Fillingham YA (2022).AAOS Clinical Practice Guideline Summary: Management of Osteoarthritis of the Knee (Nonarthroplasty), Third Edition.Intraarticular corticosteroids for short-term knee OA pain relief; limitations for long-term use2Ref 2Bannuru RR, Osani MC, Vaysbrot EE, Arden NK, Bennell K, Bierma-Zeinstra SMA, Kraus VB, Lohmander LS, Abbott JH, Bhandari M, Blanco FJ, Espinosa R, Haugen IK, Lin J, Mandl LA, Moilanen E, Nakamura N, Snyder-Mackler L, Trojian T, Underwood M, McAlindon TE (2019).OARSI guidelines for the non-surgical management of knee, hip, and polyarticular osteoarthritis.Corticosteroid injections as adjunct to core treatments (exercise, weight management) for knee and hip OA
• Inflammatory arthritis (rheumatoid, psoriatic): Injections can reduce an acute joint flare
• Bursitis (e.g., prepatellar or pes anserine bursitis): A fluid-filled sac around the knee becomes inflamed
• Acute inflammatory flares after an injury or post-procedure

They are generally not used for mechanical knee pain without inflammation — such as a clean structural meniscal tear — where they offer little benefit.

How long does a cortisone shot last in the knee?

The local anesthetic wears off within hours. Corticosteroid effects typically begin within 2-5 days and can last anywhere from a few weeks to 3 months — though this varies widely between individuals and with disease severity.

Response also diminishes with repeated injections. Most clinicians limit injections to a few times per year, because frequent high-dose corticosteroids can accelerate cartilage breakdown over time.

The OARSI guidelines for osteoarthritis management note that corticosteroid injections should be offered alongside core treatments such as exercise and weight management, not as a standalone solution 2Ref 2Bannuru RR, Osani MC, Vaysbrot EE, Arden NK, Bennell K, Bierma-Zeinstra SMA, Kraus VB, Lohmander LS, Abbott JH, Bhandari M, Blanco FJ, Espinosa R, Haugen IK, Lin J, Mandl LA, Moilanen E, Nakamura N, Snyder-Mackler L, Trojian T, Underwood M, McAlindon TE (2019).OARSI guidelines for the non-surgical management of knee, hip, and polyarticular osteoarthritis.Corticosteroid injections as adjunct to core treatments (exercise, weight management) for knee and hip OA.

What should you expect during and after the injection?

During: You will feel a needle entering the joint. Most people experience mild pressure. The anesthetic causes brief stinging, then numbness.

First 24-48 hours: Some people experience a "steroid flare" — a temporary worsening of pain as the corticosteroid crystals irritate the joint before the anti-inflammatory effect kicks in. This is normal and resolves within 48 hours.

Activity after injection: Most clinicians recommend relative rest for 24-48 hours, avoiding strenuous activity on the joint. After that, normal activity is generally permitted.

Side effects to know about: - Transient blood glucose elevation — particularly relevant for people with diabetes - Temporary skin lightening or fat atrophy at the injection site - Rarely, joint infection (septic arthritis) — aseptic technique is used to minimize this risk

Tell your clinician about any blood thinners, diabetes, or immune-suppressing medications before the procedure.

Is a cortisone shot a long-term solution for knee pain?

A cortisone injection is a short-term tool, not a cure. For knee osteoarthritis, the most durable benefits come from exercise and strengthening — which is well supported by research 3Ref 3Fransen M, McConnell S, Harmer AR, Van der Esch M, Simic M, Bennell KL (2015).Exercise for osteoarthritis of the knee.Exercise provides durable benefits for knee osteoarthritis pain and function. The injection is often most useful as a bridge: reducing pain enough to allow participation in a physical therapy program.

If injections provide diminishing relief over time and functional limitations persist, an orthopedic surgeon would discuss other options including viscosupplementation, other injection therapies, or joint replacement.

An orthopedic surgeon or sports medicine physician is the right clinician to determine whether a cortisone injection is appropriate for your specific knee condition. Gale can help you connect with that clinician and prepare your questions.