Are Cortisone Shots Bad for Your Cartilage? What the Science Shows

Your knee hurts when you walk, climb stairs, or play a sport. You ask about a cortisone shot, and a friend, a website, or an AI chatbot warns you that cortisone "eats away" cartilage and will make your arthritis worse. The concern is real enough to shape how often we give injections, but it is much smaller than the way it is usually portrayed.

A cortisone shot for an arthritic joint is a common treatment and one of the more potent tools in the toolbox for orthopedic surgeons. Lately, there has been a lot of emphasis on the potential downsides, specifically that it is bad for the articular cartilage. That claim, repeated widely online and increasingly by AI searches, traces back largely to one study. That claim is largely unfounded as we will see. Tendons are a separate matter and do deserve more caution.

The direct answer

For most people with knee or hip arthritis, an occasional, well-placed cortisone injection is a reasonable way to calm a painful flare, and there is no good evidence that it harms cartilage in any way that affects how the joint feels or works. The cartilage signal in the research comes from frequent, scheduled injections given for years, and even there the effect was very small.

What the cartilage study actually found

The study behind most of the warnings is a 2017 randomized trial by McAlindon and colleagues, published in JAMA. It enrolled 140 people with symptomatic knee osteoarthritis. Half received 40 mg of triamcinolone and half received saline, injected every 12 weeks for two years. That is eight steroid injections into the same knee, a schedule far more intensive than the occasional injection most patients actually receive.

On MRI, average cartilage thickness in the most affected part of the knee decreased by 0.21 millimeters in the steroid group and by 0.10 millimeters in the saline group. The difference between the groups was 0.11 millimeters, roughly the thickness of a sheet of printer paper, accumulated over eight injections and two years. It is noteworthy that the control group also had some thinning of the cartilage.

Statistically significant is not the same as clinically important

The trial reported the cartilage difference as statistically significant. In research, that phrase means a result is unlikely to be explained by chance alone. It does not mean the effect is large, and it does not mean the effect matters to the patient. A tenth of a millimeter can be detected with careful MRI measurement, yet the people who received steroid did not have more pain or worse function than those who received saltwater. The investigators also noted that no threshold for a clinically important change in this measurement had been defined; this is important. In today’s research, if that threshold is not set, the study is considered less valid.

The 2019 American College of Rheumatology and Arthritis Foundation guideline weighed this trial directly. Its panel judged the clinical importance of the cartilage change to be uncertain, because pain and function did not worsen, and it still strongly recommended joint injection of a glucocorticoid for knee and hip osteoarthritis. The American Academy of Orthopaedic Surgeons likewise describes knee steroid injections as a treatment that can provide short-term relief.

Expectations should also be realistic. Relief is usually temporary. Cortisone is a tool for calming a flare, not a long-term cure.

Why the danger sounds bigger online than it is

Search for whether cortisone damages cartilage, or ask an AI chatbot, and you will often get a confident answer that steroid injections "damage" cartilage or "accelerate" arthritis. Those answers usually trace back to the same small group of studies, but they tend to leave out the details that matter most: how many injections were given, how often, over how long, and how large the measured effect actually was. A difference of 0.11 millimeters after eight scheduled injections becomes, in a headline or a chatbot summary, a blanket warning about any cortisone shot.

This pattern is not surprising. Headlines reward alarming phrasing, social media rewards simple rules, and AI tools learn from that same body of online writing, so they can repeat a caution without the context that keeps it in proportion. If something you have read is making you hesitant, bring it to your orthopaedic surgeon. A conversation about your joint, your imaging, and your treatment history is a better guide than a general rule stripped of its numbers.

What this means for an arthritic knee

A cortisone shot can be a reasonable choice when knee arthritis is causing a painful flare, interfering with sleep, or making it hard to exercise or complete physical therapy. The goal is symptom control. It does not rebuild cartilage or change the underlying arthritis, but used occasionally, it is not a meaningful threat to the joint.

The decision should account for your symptoms, examination, imaging, other treatments, diabetes status, and any surgery you may be considering. Often the greatest value of an injection is that it lets you move comfortably enough to resume a strengthening program, which remains one of the most effective long-term treatments for knee arthritis.

Real-world data are reassuring. Large observational studies that followed people with knee osteoarthritis for years, including a five-year French cohort and an analysis of two major U.S. cohorts, did not find that steroid injections led to more knee replacements than no injection or than hyaluronic acid injections. Studies of this kind cannot prove that injections are harmless for every patient, but they do not show the steady march toward joint replacement that online warnings imply.

How often can you get cortisone shots?

There is no single number that applies to every joint and every patient. In practice, injections are spaced out over many months not weeks, and we reassess whether the previous injection provided meaningful relief before repeating it. Treating an occasional flare is very different from injecting on a fixed calendar, which is the pattern tested in the trial above.

Each injection carries small risks, including infection, a temporary rise in blood sugar, and skin or fat changes near the injection site. If relief lasts only briefly or injections are becoming frequent, that is a signal to revisit the overall plan rather than simply repeat the shot.

A note on the hip

A minority of patients develop rapidly progressive hip arthritis after an injection. In one retrospective study, this occurred in about 5.4% of injected hips, and the risk was concentrated among patients who received higher doses and multiple injections. This is not a reason to avoid hip injections, but it is a reason for careful diagnosis, a sensible dose, and prompt follow-up if hip pain changes suddenly. Most patients only receive 1 or 2 hip injections before moving on to replacement. The hip and knee are very different joints.

Tendons deserve more caution than joints

A steroid injection inside an arthritic joint is not the same as an injection into or around a tendon. Tendons have a different blood supply and structure, and laboratory and clinical research shows that local steroids can reduce the activity of tendon cells and their production of collagen, which can weaken the tissue.

For that reason, we are cautious with cortisone for Achilles or patellar tendon problems, and we avoid injecting directly into a tendon, which can fail under load once weakened. Tendon pain usually responds better to a progressive loading program and activity modification after the diagnosis is confirmed.

Rotator cuff pain

For shoulder pain related to the rotator cuff, a steroid injection can provide short-term relief, which can be useful when pain is blocking sleep or rehabilitation. Used sparingly, it can be a reasonable bridge to therapy. It does not repair a torn tendon. Because the rotator cuff is so important, injections are usually limited to 1 or 2 over multiple years.

Timing matters if rotator cuff surgery is a possibility. A systematic review found associations between preoperative steroid injections and higher revision rates after rotator cuff repair, especially with multiple injections or injections given closer to surgery. It also reported a higher infection risk when an injection was given within one month before repair.

A painful stiff shoulder, such as adhesive capsulitis (frozen shoulder), is generally a more favorable reason for a shoulder injection than a tendon that must withstand heavy loading.

Tennis elbow

Tennis elbow is a useful reminder that short-term relief does not always mean long-term improvement. In a randomized trial, people who received a corticosteroid injection had lower recovery rates at one year and more recurrence than those who received placebo. That finding applies to tennis elbow specifically, but it is why repeated steroid injections are not our default for chronic tendon pain.

Other practical precautions

If you have diabetes, expect a temporary rise in blood sugar after an injection. A systematic review found this in all included studies, with peaks often occurring within 24 to 72 hours. It is usually manageable with closer monitoring, so ask your clinician how to check your glucose and which readings warrant a call.

Joint infection after an injection is rare. A large multicenter review reported septic arthritis after roughly one in 15,275 corticosteroid injections. Still, increasing pain, warmth, redness, fever, or feeling unwell in the days after an injection should be evaluated promptly.

Timing also matters before joint replacement. A large study found a higher risk of infection after knee replacement when a corticosteroid injection was given within three months before surgery, with no increased risk when the interval was longer. If knee replacement is on the horizon, make sure your surgeon knows about any recent injection.

The bottom line

If you have knee arthritis and are weighing a cortisone shot, these questions are worth discussing with your surgeon:

• What problem is the injection meant to solve, and how long might the benefit last?
• Is this an occasional treatment for a flare, or a repeating schedule?
• Am I likely to need knee replacement, rotator cuff repair, or another procedure in the next few months?

Used thoughtfully, a joint injection is a low-risk, well-established short-term tool, and the fear that an occasional shot will wear away your cartilage is not supported by the evidence. Injections work best as part of a broader plan that includes exercise, strengthening, and reassessment if symptoms persist. For tendon problems, confirm the diagnosis and discuss tendon-specific options first.

Learn more about joint injections: https://www.mdorthospecialists.com/services/joint-injection-therapy/