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What You Need to Know From a Physiotherapist’s Perspective

You’ve been managing pain or a stubborn injury for a while now—maybe it’s your shoulder, knee, hip, or lower back—and your GP or specialist has just mentioned cortisone injections. Suddenly, your brain is full of questions:

What exactly is a cortisone injection?

How long will it take to feel better?

Will I need to rest for weeks after the injection?

When can I start exercising again? Should I expect long-term benefits, or is this just a temporary fix?

Do I still need to do physiotherapy after the injection, or is this the quick solution I’ve been waiting for?

If you’re feeling unsure or overwhelmed—trust me, you’re not alone. These are some of the most common questions people ask when cortisone is mentioned, and they’re all completely valid.

Whether you’re someone who’s tried everything and is looking for relief, or you’re just starting your rehab journey and trying to understand your options, this blog is for you. We’ll break down what cortisone injections actually do, how they fit into your recovery plan, when they can help (and when they might not), and how to get the most out of them with the right physiotherapy—because while injections can provide pain relief, they’re only part of the puzzle.

What Is a Cortisone Injection?

Cortisone injections (also called corticosteroid injections) are used to reduce inflammation and relieve pain in a specific area, often around a joint, tendon, or bursa. In many cases, the injection is done under ultrasound guidance to improve accuracy and ensure the medication reaches the right spot. Cortisone injections are often used as part of a broader treatment plan to support recovery and improve function.

What’s in It?

The injection usually contains:

  • Corticosteroid – the anti-inflammatory medication that reduces swelling and irritation
  • Local anaesthetic – provides short-term pain relief during and shortly after the injection
  • Saline (sometimes) – helps dilute the injection or flush the joint if needed

What Is Inflammation?

Inflammation is the body’s natural response to injury, irritation, or overload. It’s a key part of the healing process—bringing increased blood flow, immune cells, and nutrients to the affected area to help repair damaged tissues and begin recovery. This response can cause redness, heat, swelling, and pain as the body works to heal itself.

Inflammation can be:

Acute – short-term, usually starting suddenly after an injury (like swelling after a sprained ankle) and typically resolving as healing progresses

Chronic – long-term, where the inflammation persists even after the original injury has healed or when an area is repeatedly stressed or irritated

While inflammation is essential for healing, chronic inflammation can become a problem. It may cause ongoing pain, stiffness, swelling, and reduced movement. When this happens, and other treatments haven’t worked, a cortisone injection might be considered to help settle the inflammation.

How Do Cortisone Shots Work?

The cortisone works by calming down the inflammatory process in the area it’s injected into. This helps reduce swelling and heat, and give pain relief, which in turn makes it easier to move, sleep, and get back into your rehab exercises or daily activities. It’s especially useful when inflammation is so persistent or severe that it’s blocking progress.

But here’s the key point: a cortisone injection doesn’t repair or heal the underlying injury. It doesn’t rebuild damaged tissue or fix the root cause. What it does is create a window of relief—reducing inflammation enough so you can do the things that actually help it heal—like targeted physiotherapy, strength work, or addressing biomechanical issues.

When Might You Need To Get a Cortisone Shot?

Cortisone injections are usually considered when:

  • There’s ongoing inflammation in a joint, tendon, or bursa (e.g. frozen shoulder, bursitis, knee osteoarthritis, plantar fasciitis, carpal tunnel syndrome)
  • You’ve tried conservative treatments (such as physiotherapy, rest, and activity modification) for at least 6 weeks with limited improvement
  • Pain is restricting your ability to move, work, or participate in exercise
  • You’re experiencing a flare-up that’s preventing meaningful progress in rehab
  • Pain is persistent or severe enough to disturb your sleep

In other words, if your pain is so flared up that even basic rehab exercises are difficult, a cortisone injection might help settle things so you can move forward. But it’s not always the first line of treatment—and not everyone needs one.

It’s typically a last resort before considering surgery, or used to settle things down enough so that you can actually participate in rehab.

Note: Physiotherapists can guide you through conservative rehab and let you know when it’s worth exploring other options, but cortisone injections are prescribed and administered by your GP or specialist. If this sounds like your situation, have a chat with your doctor.

Try Conservative Management First

Before jumping to an injection, most people benefit from giving conservative management a proper go—usually for at least 6 weeks. This often includes:

  • Activity modification – reducing or adjusting movements that aggravate symptoms
  • Targeted exercise therapy – building strength, flexibility, and control in the affected area
  • Manual therapy – hands-on treatment (if needed) to reduce stiffness or improve mobility
  • Education – understanding your condition, pain triggers, and how to avoid flare-ups
  • Load management – learning how to balance rest and activity without over- or under-doing it

In many cases, a well-structured rehab plan can help you recover without needing an injection at all. And even if an injection does become necessary, the physiotherapy you’ve done beforehand puts you in a stronger position to get the most benefit from it—and bounce back faster.

What to Expect After the Injection

Will it work straight away?

You might feel a little bit of relief within a few hours—that’s the local anaesthetic kicking in. However, it’s also common to have a “steroid flare” where pain actually worsens for 1–2 days.

Is it a quick fix?

Not exactly. Some people feel better within days, others take 1–2 weeks to notice improvement. A small group may not feel much change at all.

Will it fix the problem forever?

No. Cortisone helps with inflammation and pain, but it doesn’t heal damaged tissue or correct movement dysfunction. That’s where physiotherapy comes in.

Do I still need to do physiotherapist after the injection?

Yes—absolutely. Cortisone can create a really good “rehab window” where pain is lower, allowing you to do strength, mobility, and movement work more comfortably.

When Should I Start Physiotherapy Again?

After a cortisone injection, it’s usually recommended to rest the area for about 1–2 weeks. This rest period is crucial because it gives the steroid time to settle and begin working most effectively in the targeted area, particularly if the injection is in a joint or tendon. Resting helps ensure that the medication stays in place and doesn’t get moved around too quickly, allowing it to reduce inflammation and provide long-lasting relief.

During this time, it’s important to avoid excessive movement or strain to give the cortisone its best chance to work. Once the initial rest period is over, your physiotherapist can guide you back into graded movement and strengthening exercises. However, the timing will depend on how you’re feeling and what area was treated, so it’s always a good idea to check in with your physiotherapist before resuming more intense activity.

The Rehab Window: Making the Most of It

Cortisone can reduce pain enough to allow you to do the physiotherapy exercises that previously hurt too much. This creates a critical “rehab window”—a period when your body is more comfortable, and you’re able to move more freely.

Use this time to:

  • Build strength and mobility
  • Correct movement patterns that may have led to the issue in the first place
  • Prevent future flare-ups or injuries

This is when the real recovery happens. Don’t waste the window. Cortisone doesn’t fix the problem—but it gives you the opportunity to do the things that do. This when your recovery really happens.

Timeline for Recovery

  • Day 1–2: Pain flare-up possible
  • Day 3–7: Gradual reduction in pain and stiffness
  • Week 2: Begin rehab (gentle at first)
  • Weeks 2–6: Build strength and mobility
  • Ongoing: Progress to return to work/sport/life goals

Common Side Effects and Risks

Most people tolerate cortisone injections well, but potential side effects can occasionally occur. These include a temporary increase in pain (known as a steroid flare), skin thinning or lightening at the injection site, fat atrophy, or raised blood sugar levels, especially in people with diabetes. Although rare, infection is a possible risk. Repeated injections into tendons may also lead to tendon weakening over time.

How Many Injections Can I Have?

Doctors generally recommend no more than 3 injections per year in the same area, as repeated use can affect tissue health—particularly in tendons and cartilage. Over time, excessive corticosteroid exposure can weaken soft tissues, reduce their ability to heal, and may limit the long-term effectiveness of the injection. This is why cortisone is best used alongside a strong rehab plan—not as a stand-alone solution. 

Always discuss the risks and benefits with your GP or specialist and how many are appropriate for you.

Final Thoughts

Cortisone injections can be a helpful part of your recovery journey—but they’re not a cure. They work best when they’re used at the right time, for the right condition, and are followed up with active physiotherapy.

If you’re struggling with pain or inflammation that’s stopping your progress, speak to your GP about whether a cortisone injection might be a good option for you. And remember—movement is medicine, but timing matters.

If you or someone you know is experiencing pain or injury, why not give us a call on 0298753760 to discuss your options, or you could book an appointment online. At West Pennant Hills Physiotherapy, we have a lot of experience, and would be happy to help you navigate your path to recovery.