A cortisone injection into the knee is a common treatment for reducing inflammation and pain caused by conditions such as osteoarthritis or tendonitis. The injection consists of two primary components: a corticosteroid, which is the long-acting anti-inflammatory agent, and a local anesthetic, which provides immediate, short-term pain relief. This combination delivers the powerful anti-inflammatory medicine directly to the affected joint space, maximizing its therapeutic effect while minimizing systemic side effects. Understanding post-procedure activity is important for ensuring the medication works correctly and avoiding potential complications.
The Immediate 48-Hour Activity Protocol
Rest is necessary immediately following the injection, typically for a period of 24 to 48 hours. This initial restriction on activity is designed to allow the corticosteroid medication to settle within the joint space. Minimizing movement helps prevent the medicine from being rapidly absorbed into the bloodstream or displaced from the intended target area, which maximizes the local anti-inflammatory concentration.
The local anesthetic provides an almost immediate numbing effect that can mask the underlying pain. This temporary relief can lead a person to believe they are ready for full activity right away, but the cortisone’s anti-inflammatory effect takes a few days to begin working. Overuse of the knee during this initial window, while the joint feels pain-free, may increase the risk of cartilage damage associated with steroid exposure.
For the first two days, high-impact or strenuous activities must be avoided completely, including running, jogging, high-intensity workouts, or heavy weight training. Routine daily activities, such as light walking around the house, are generally permitted and can help prevent stiffness. However, any movement that causes increased discomfort should be stopped immediately.
Physicians often recommend using ice on the injection site for short intervals during the first day to manage any temporary soreness or swelling. It is also advised to avoid soaking the knee in a bath, hot tub, or pool for at least 24 to 48 hours to minimize the small risk of infection. Following the specific post-procedure instructions given by the healthcare provider is the most effective way to ensure the best possible outcome.
Gradual Return to Movement and Exercise
After the initial 48-hour restrictive period, a phased return to normal activities should begin slowly, guided by how the knee feels. Most patients can start to reintroduce light activities, such as gentle stretching, stationary cycling, or extended walking, around day three. The goal during this phase is to maintain the joint’s range of motion without putting excessive load or strain on the treated area.
Many people experience a temporary increase in pain and swelling within the first 24 to 72 hours after the injection, known as a “cortisone flare.” This reaction is thought to be caused by the body’s response to the steroid crystals in the joint fluid. This flare-up is typically short-lived and does not indicate a treatment failure, with the true anti-inflammatory benefits often becoming noticeable within three to seven days.
A return to more demanding physical activities, like heavy lifting, intense physical therapy, or sports, should typically be delayed until at least one week post-injection. For high-impact activities such as running, clinicians advise waiting a full week or more to allow the corticosteroid to fully exert its effect and ensure the joint is stable. When reintroducing exercises, it is wise to start with low-impact movements and gradually increase intensity, paying close attention to the body’s signals.
Physical therapy, if recommended, can usually begin a few days after the procedure, focusing initially on gentle movements and gradually progressing to strengthening exercises. It is common for the incorporation of full strengthening exercises to be delayed until around four weeks post-injection. Listening to the knee and avoiding any movement that reproduces the original pain is the most important principle during this gradual return.
Signs of Overexertion or Adverse Reactions
While cortisone injections are generally safe, understanding the warning signs of a complication is important. The most serious, though rare, complication is a joint infection, which requires immediate medical attention. Signs of an infection include a fever, severe pain that rapidly worsens instead of improving after 48 hours, or pronounced redness, warmth, or drainage at the injection site.
Other adverse reactions can indicate overexertion or a systemic response to the medication. Patients with diabetes should monitor their blood sugar closely, as a temporary increase in glucose levels is a known side effect of corticosteroids. Some individuals may experience facial flushing or a feeling of warmth in the chest and face for a few hours after the procedure, which is a common, non-serious reaction.
If the initial pain relief from the local anesthetic wears off and the subsequent pain is worse than before the injection and persists beyond three days, it may signal that the knee was overused or that the steroid flare is prolonged. Other minor side effects can include temporary skin discoloration or mild thinning of the skin around the injection site. Any concern about new or worsening symptoms should prompt a consultation with the prescribing physician.