Image result for knee injections
Are injections a reason to jump for joy?

Let’s Talk Knee Injections

Knee injections are a common practice when a patient visits his or her primary care physician complaining of knee pain. It’s a simple treatment that requires minimal to no examination and little effort on the part of the practitioner. My goal is to inform you on the subject of injections and if they’re the right fit for you.

I will go over 3 types of injections that are the most common today. The big three are:

  • Corticosteroid
  • Hyaluronic Acid
  • Platelet Rich Plasma (PRP)

Steroids (for the knee)

Corticosteroids, or also known as hydrocortisone (it has many names), are derived from agave plants. Who knew? Not me. Turns out these plants have some really interesting properties that we like to put into our knees. Anyways, the idea behind corticosteroid injections is that they reduce inflammation in the joint and improve overall movement. Average treatment normally requires 1-3 injections.

Now, this is where things get twisty. Not many studies show any benefit from these injections, especially past the FIRST month. The evidence on these studies is either poor due to excessive bias in the research, or lack of successful outcomes. In fact, the American Association of Surgeons (AAOS) can neither recommend for or against steroid injections due to the iffy research. On the flip side, the adverse effects are very low beside the possible wasting of cash coming out of your pocket. If you think this is worrisome, get ready for hyaluronic acid.

man holding syringe for knee injection
Pray this man is not your physician…

Liquid Rooster Combs

Hyaluronic acid is derived from rooster combs. Yes, I said it, rooster combs. But so are amino acids that people drink every day. The thought process of injecting liquid rooster comb is that it contains much of the same type of fluid-structure as our synovial fluid (joint lubricant). Better viscosity in the joint= increased movement = less pain. On average, 1-5 injections are given over a period. And yet, nothing really shows that this works. The evidence for hyaluronic acid is so poor, the AAOS does NOT recommend it. Much like the steroids, research has excessive bias and a lack of intention to treat. The adverse effects are worse too, with higher chances of swelling and site reactions. With only one more injection to look at, is platelet-rich plasma the answer to knee osteoarthritis and knee pain?

Is PRP the Holy Grail?

Platelet-Rich Plasma (PRP) Injections come straight from our bodies. It is drawn out of the patient’s blood and the idea behind injecting in the knee is not well known yet. I was intrigued while reading the main articles on PRP injections because there is no real thought process on why it would even work. 1-4 injections are usually performed. And like the other injections, not much success is shown after one year. It is inconclusive at best. Like the other studies, too much bias is involved and PRP lacks enough successful outcomes to show promise. The AAOS can’t recommend for or against the injections yet because there is not enough research around PRP in the knee.

Conclusion on Knee Injections

Knee injections in studies don’t show enough promise. In my research, I have found that knee pain and X-Rays are not always the best indication for injections (which most of these studies said they used). I believe a thorough examination can springboard a proper diagnosis of knee pain and effective conservative treatment should be the first line of defense.

Tyler Burton, PT

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