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What are the disadvantages of knee injections?
The disadvantages of knee injections are short-lived relief, a real cost to the joint when steroid shots are repeated too often, side effects such as a temporary pain flare or a rise in blood sugar, a small risk of joint infection, and out-of-pocket expense for the treatments insurance will not cover.
I still give these shots every week, so I am not against them. They are simply not free, and the trade-off differs by type.
After more than twenty years in practice, and roughly 700 hip and knee replacements a year, here is how I sort this out with patients from Franklin, Nashville, and Columbia.
Do knee injections damage knee cartilage?
Repeated cortisone (steroid) injections can be hard on cartilage, which is why I limit how often I give them. One shot is a different conversation from a shot every three months for years.
The key evidence is a two-year randomized trial of 140 patients with knee arthritis. Those given triamcinolone (a steroid) every 12 weeks lost significantly more cartilage volume than those given saline, without better pain relief.
The picture is not fully settled. A later study of more than 980 knees followed for seven years found similar arthritis progression between steroid and gel injections, so some of the earlier signal may reflect worse arthritis in the patients being injected.
Here is what I tell my patients: treat cortisone like a strong tool, not a routine.
How many cortisone shots can you have in a year?
A common and sensible routine is up to about three cortisone injections a year in the same knee. That pace gives most patients meaningful relief without the exposure that worries me.
Relief length varies widely, from a day to several months. Asking for a fourth or fifth shot in a year is usually the knee telling us something: a signal to change the plan, not to keep injecting.
What are the common side effects of knee injections?
Most side effects of knee injections are local, mild, and short. Mild pain or swelling at the injection site happens in up to 20 percent of patients and usually settles within a couple of days. The ones I counsel patients about most often:
- A post-injection flare. The knee can hurt more for 24 to 48 hours before the steroid takes hold. Rest it for a day and skip heavy exercise.
- Blood sugar changes. Cortisone can raise blood glucose for several days, so patients with diabetes should tell us first and watch their numbers.
- Skin changes at the site. Thinning, lightening, or a small dimple of fat loss can occur, and it is not always reversible.
- Tendon weakening. Repeated steroid near tendons has been linked to degeneration and, rarely, rupture.
- Systemic effects. Frequent steroid can suppress the adrenal glands and contribute to bone thinning.
Can knee injections cause an infection in the joint?
Yes, and this is the rare complication I take most seriously. Septic arthritis (a joint infection) after an injection is uncommon, and it is a surgical emergency when it happens.
Call the office the same day if your knee turns hot, red, and much more swollen two or three days after a shot, especially with fever or chills.
Timing matters too. Studies have linked a steroid injection given within about three months of knee replacement to a higher infection risk after that surgery, so if surgery is close, I hold the shot.
What are the downsides of gel (hyaluronic acid) injections?
The gel injection does not grow new cartilage, and national guidelines do not strongly recommend it. Those two facts are the main drawbacks, and patients deserve to hear them plainly.
A simplified picture: the gel goes in and the cartilage you still have soaks it up a little like a sponge soaks up water, helping that cartilage work as a better shock absorber. The real mechanism is more complicated, but the concept holds.
Because it works with the cartilage you have left, it helps mild to moderate arthritis far more than a bone-on-bone knee. About eight out of ten of my patients get relief for at least six months, and some do well for two to three years.
In the interest of honesty: the American Academy of Orthopaedic Surgeons does not strongly recommend the gel, and the published evidence is mixed. This is one place I sit apart from the guideline: many of my patients respond well, and in our region insurance still covers it.
One practical note. You may be offered a single injection, a three-shot series, or a five-shot series. The active ingredient is the same, so whichever your insurance approves, expect similar results.
What are the drawbacks of PRP injections for knee arthritis?
The drawbacks of PRP are cost, inconsistent evidence, and wide variation in what you actually receive. PRP (platelet-rich plasma) draws a small amount of your blood, concentrates the platelets, and puts them back into the knee to calm inflammation.
Insurance does not cover it, and some clinics charge a great deal. In my clinic it is offered at the cost of the kit, with no markup.
The evidence is still moving. A large placebo-controlled randomized trial compared PRP with saline and found no significant difference in pain or joint structure at one year, while other studies have been more favorable. About seven out of ten of my patients report relief lasting six months or more, so I offer it with clear expectations rather than promises.
Be a smart shopper. Preparations differ, including white blood cell (leukocyte) content, so ask exactly what you are getting, and know that some clinics market “stem cells” while injecting PRP. For more, read what the PRP evidence actually shows.
Why do I tell patients to skip stem cell injections for arthritis?
For broad knee arthritis, there is no credible evidence that stem cell injections work, and they are expensive. That combination makes this the one shot I steer patients away from.
A 2024 review of 16 randomized trials, covering 807 participants, found that stem cell injection probably provides little to no improvement in pain or function, and may increase side effects.
The marketing claim that stem cells grow new cartilage has not been shown. Maybe that changes someday. The science is not there yet.
Here is how I put it across the desk: if stem cells were free, I would still tell you not to do this for arthritis. They are not free, and people are spending large sums on a promise that is not real yet.
One fair caveat: narrow uses for biologics exist, such as a focal cartilage defect in a younger patient. That is different from bone-on-bone arthritis. More detail here: stem cells for arthritis, hope or hype.
What should you try before knee injections?
Start with what you control. A shot works best alongside these basics, not instead of them.
- Regular movement: walking, cycling, or pool work
- Strengthening the quadriceps and hip muscles around the knee
- Keeping weight in a healthy range, since every pound counts across the joint
- Simple over-the-counter anti-inflammatories when safe for you
- Bracing, activity changes, and physical therapy
For the full picture of conservative care, see our page on nonsurgical joint pain treatment. Earning your way up the ladder is how you get the most out of every step, injections included.
When do knee injections stop being the right answer?
Injections stop being the right answer when they no longer buy meaningful time. That is the practical test I use in clinic.
None of these shots cure arthritis. The only cure is replacing the joint, and surgery should still be the last resort.
Watch the interval, not just the relief. When a shot that used to carry you six months only carries you six weeks, the arthritis has outgrown the injection.
Putting off knee replacement for a few good years with a shot that works is a win, not a failure. This is a quality-of-life decision: if your pain and your limits were taken away, how much would your life change? Read more about when it is time for a knee replacement.
Talk it through with a Franklin, TN orthopaedic surgeon
If your knee has been through a few shots and you are unsure what comes next, talk with someone who does this daily. I see patients from Franklin, Nashville, Brentwood, Spring Hill, and Columbia at the Bone and Joint Institute of Tennessee, 3000 Edward Curd Lane, Franklin, TN 37067.
Call (615) 791-2630 or schedule a consultation with Dr. Calendine. Bring your imaging and injection history; both change the plan.
Key takeaways on the disadvantages of knee injections
- Relief is temporary with every injection type
- Repeated steroid carries a cartilage and tendon cost; three a year is a sensible ceiling
- Gel does not rebuild cartilage; PRP is out of pocket with mixed evidence; stem cells are unsupported
- Report a hot, swollen knee with fever the same day
Medical disclaimer: This article is for educational purposes only and does not replace advice from a qualified orthopaedic clinician. It reflects Dr. Calendine’s independent clinical perspective. Individual results vary. Always consult your own physician before making treatment decisions.
References
- McAlindon TE, LaValley MP, Harvey WF, et al. Effect of intra-articular triamcinolone vs saline on knee cartilage volume and pain in patients with knee osteoarthritis: a randomized clinical trial. JAMA. 2017;317(19):1967-1975.
- Bennell KL, Paterson KL, Metcalf BR, et al. Effect of intra-articular platelet-rich plasma vs placebo injection on pain and medial tibial cartilage volume in knee osteoarthritis: the RESTORE randomized clinical trial. JAMA. 2021;326(20):2021-2030.
- Sadeghirad B, Rehman Y, Khosravirad A, et al. Mesenchymal stem cells for chronic knee pain secondary to osteoarthritis: a systematic review and meta-analysis of randomized trials. Osteoarthritis Cartilage. 2024;32(10):1207-1219.
- Brophy RH, Fillingham YA. AAOS clinical practice guideline summary: management of osteoarthritis of the knee (nonarthroplasty), third edition. J Am Acad Orthop Surg. 2022;30(9):e721-e729.
- Cheng J, Abdi S. Complications of joint, tendon, and muscle injections. Tech Reg Anesth Pain Manag. 2007;11(3):141-147.
- Yang X, Li L, Ren X, Nie L. Do preoperative intra-articular injections of corticosteroids or hyaluronic acid increase the risk of infection after total knee arthroplasty? A meta-analysis. Bone Joint Res. 2022;11(3):171-179.
Watch: an honest look at knee injections for arthritis
I walk through all four injections the way I would across the desk in clinic, including how long relief tends to last and the one shot I tell patients to skip.
