Knee arthritis can take a real toll, and many patients ask me about injections before considering surgery. They can help a lot, but it's important to understand what each type can and can't do.
Cortisone shots
Cortisone is the traditional injection for arthritis. It works by calming inflammation and can be very effective for pain, but it's a short-term fix. Relief often lasts up to a couple of months, sometimes only several weeks; newer extended-release versions can stretch that out. Cortisone shots are generally spaced about every four months, and they tend to become less effective with repeated use. They're often covered by insurance.
Gel shots (hyaluronic acid)
Hyaluronic acid works a bit like a lubricant for the joint, helping it move smoothly. Depending on the product, treatment is 1 to 5 injections over several weeks. Results vary: some people get months of relief, others less. Gel shots are approved for the knee. More about gel injections.
PRP (platelet-rich plasma)
PRP is made from your own blood, which is spun to concentrate the platelets and their growth factors, then injected into the joint. It has become one of the injections I recommend most for knee and hip arthritis and for stubborn tendon problems. In research comparisons, PRP has outperformed both gel shots and cortisone for knee arthritis at six to twelve months, and a 2025 analysis of 18 randomized trials found it improved pain and function more than placebo. PRP is usually not covered by insurance. Read more about PRP injections.
Stem cell injections
These use cells taken from bone marrow or fat. Some people report relief, but the science is limited and their use is controversial. They tend to be expensive and are rarely covered by insurance. I explain more in what the FDA says about stem cell injections.
When injections make sense
For persistent arthritis pain, I usually start with conservative care: activity changes, ice, bracing and physical therapy. If that isn't enough, an injection is often worth trying. It isn't a permanent fix, but it can delay the need for surgery, and sometimes it relieves enough pain to let you get more out of physical therapy. Injections are very safe, with a very small risk of infection, and image guidance can help place the injection precisely in the joint.
If injections stop helping and pain is limiting your life, that's when we talk about whether a partial or total knee replacement makes sense.
- Adapted and updated from Dr. Akhtar's column, “Worth a Shot: How Helpful are Knee Injections for Arthritis Pain?” Inova Newsroom, August 2019.
This article is for general education and is not medical advice. Talk with your surgeon about your own situation.