Injections for knee osteoarthritis

What are the Types of Knee Injections?

There are several types of knee injections. Some your doctor will tell you about and some may not be discussed. My goal here is to cover everything that can be injected into your knee that may help arthritis or pain.

What are the Options?

There are many different options or types of knee injections which include:

  • Steroids (corticosteroids or cortisone)
  • Viscosupplementation (knee gel shots)
  • Prolotherapy
  • Ozone
  • Platelet-Rich Plasma (PRP)
  • Stem Cell Injections (BMC or BMAC)
  • Amniotic or Umbilical Cord Tissue
  • Microfragmented Fat (Lipogems)
  • Cytokine Enriched Plasmas (A2M or IRAP)
  • Exosomes

Regrettably, most physicians will only discuss the first two, because, at this point, that’s what’s covered by insurance, but here you’ll get all the options. Let’s dig in:

Traditional Types of Knee Injections


These are powerful anti-inflammatory medications that can reduce swelling, also known as corticosteroids (cortisone). This is by far the most common knee injection performed worldwide to treat knee pain due to arthritis. The problem is that recent high-level research shows that they don’t work as well as we once thought and destroy normal cartilage (1). Hence, we no longer use these shots in our clinic.


This is a fancy word for a knee gel injection. Basically, these products mimic the natural fluid (synovial fluid) that is found in the knee to provide additional cushioning and help cartilage. Different products have different weights of the chemical hyaluronic acid (HA). Brand names include Synvisc, Orthovisc, Euflexxa, and Supartz. The research on whether these injections help is all over the map at this point, meaning some studies say yes and others no (2, 3). However, overall, they seem to work for about 6 months. There is no research that says they hurt cartilage and most studies point in the direction of HA helping arthritis (4).

Newer Types of Knee Injections

Prolotherapy (Prolo)

The “prolo” in prolotherapy is short for “proliferative” which means the injection of a substance which is a chemical irritant which can kick off a healing cycle. The concept is not new but has been revived in the past 10-20 years. The injections are usually of “hypertonic” dextrose which is more concentrated than your body fluids (30).

The research on prolotherapy does show that it works reasonably well, less than PRP, but better than anesthetic or steroid injections (29). The nice thing about “prolo” is that it’s pretty cheap, usually, about half the price of a PRP shot or less. It is not, however, covered by insurance. However, animal studies show that it helps cartilage.


Ozone is what it sounds like, the stuff that makes up the ozone layer of the atmosphere. Instead of O2 this is O3, the idea being that it can give off oxygen providing better oxygenation of the area. The machines that make ozone are not FDA approved for human use in the United States, hence this procedure is used more often in Europe than in the US.

The research on knee arthritis treatment does show good results in high-level trials (31), although PRP generally beats these outcomes (34). The treatment is often inexpensive, with a similar cost to prolotherapy. It’s not covered by insurance and we don’t have much research that shows positive effects on cartilage.

Platelet-Rich Plasma (PRP)

PRP is created by concentrating platelets from a blood draw. The platelets then release growth factors that can reduce swelling and help cartilage cells. The research on efficacy for knee arthritis is pretty good with multiple studies showing that PRP beats gel shots (5). However, this is not yet covered by insurance, with costs ranging about $1-2,000 USD per injection. One caveat is that Regenexx has been able to get coverage from large self-insured employers, but not yet major health carriers. A few auto insurances or worker’s comp carriers may also pay for PRP.

For mild knee arthritis, the injections can last about a year, but for more severe arthritis the effect is shorter (6). However, a big plus here is that this is a regenerative injection with some evidence for regenerating or helping cartilage cells (7). In addition, PRP can be used to treat tendons, which are also found around the knee and can be painful.

Stem Cell Injections

Stem cell injections are usually performed for more severe knee arthritis. There are many types, with the only US legal version being bone marrow concentrate (aka BMC or BMAC). In this procedure, the doctor takes a bone marrow aspirate from the back of the hip (PSIS area) and then concentrates the stem cell fraction of the bone marrow in a centrifuge. The research is still in it’s early stages, but our group has published the largest randomized controlled trial to date (Regenexx procedure) showing good results (8). However, another smaller RCT using a very different technique didn’t show positive outcomes (14). Other lower levels studies show positive results (18, 26, 27). Like PRP, these procedures are not covered by insurance and tend to run 2-3 times as much as that procedure. Unlike PRP, they tend to work well for more severe arthritis patients (9). Like PRP the benefit is that research has shown that the mesenchymal stem cells in bone marrow can help cartilage repair (13). The Regenexx procedure has been able to get coverage from select employers. In addition, some worker’s comp (WC) or auto insurance carriers (auto) may provide coverage.

Amniotic or Umbilical Cord Tissue

These therapies are all derived from birth tissues that are normally considered medical waste. The amniotic sac surrounds the baby and yields amniotic membrane/fluid and the umbilical cord connects the baby to the mother and yields umbilical cord blood and Wharton’s Jelly. These products are sold to doctors either dehydrated or frozen.

Many providers claim that these are “stem cell” therapies, but while fresh birth tissues can yield stem cells, once sourced, transported, processed, frozen, and shock thawed no MSCs survive (10-12). They do contain growth factors, but even these levels are oftentimes lower than those found in PRP. However, they may also contain unique growth factors that could help cartilage.

Right now, we have little research that these vastly different products help knee arthritis. However, some research does exist. For example, a high-level trial of ReNu (amniotic membrane) showed good short term 6-month results in knee arthritis. These procedures are not covered by insurance and are expensive. However, there is basic science data that the base materials used in some of these products may help cartilage.

Microfragmented Fat

Microfragment fat (Mfat) is what it sounds like. Doctors take fat via a mini-liposuction procedure and use a lab to process it or use a kit called Lipogems (15). This is different than a fat stem cell procedure known as SVF (Stromal Vascular Fraction) where the fat is digested, which is not legal in the US at this point, although some doctors are floating that risk (16). The early research on Mfat looks promising with some reports of improved cartilage on MRI in small studies (17). Head to head research that compares Mfat to BMC demonstrated that they both helped knee OA to the same degree (18). Like PRP, this isn’t covered by insurance and costs about the same as a BMC procedure. Also like PRP and BMC, limited insurance coverage may be available through Regenexx or WC/auto.

Cytokine Enriched Plasmas

Some of the newest orthobiologics (a term that encompasses all of these natural therapies derived from the body) are focused on concentrating natural chemicals in the blood (cytokines) that may help reduce cartilage breakdown. These include treatments like the Cytonics A2M procedure and the Orthokine or Regenokine procedure (IRAP). A2M is a natural cytokine found in your blood that has been shown in animal models to inhibit cartilage breakdown (19). IRAP (or IL-1ra) is also a cytokine that is produced by white blood cells which blocks other inflammatory chemicals in the knee (IL-1b) (21). The research on A2M is in its infancy, with no clinical trials to date, but promising animal models (20). The research on IRAP is more mature and one study showed reasonable efficacy (22). These procedures are not covered by insurance and generally run somewhere between the cost of a PRP and a bone marrow stem cell injection, but like PRP tend to work better in less severe knee arthritis.


One of the newest treatment options being offered to treat knee arthritis is a product called “exosomes”. These are small packets of information and cytokines released by stem cells as they grow (23). While there is some interesting lab and animal data on the concept, none of that data was collected on the actual products being sold and used in patients (24). In addition, there is no clinical data showing that this works in actual patients with knee arthritis. Finally, these procedures aren’t covered by insurance and can be very expensive, often costing as much as a bone marrow stem cell procedure.

You Need Imaging Guidance to Inject a Knee!

Do not allow a physician or other provider to inject your knee without either ultrasound or x-ray guidance, as blind injections have a significant miss rate. This means that the doctor won’t actually get the substance in your knee joint. In order to see how difficult it can be to inject a knee properly using ultrasound, see a course I taught physicians below:

What is the Best Knee Injection?

As you can see, there are many types of knee injections and they all have pros and cons. To the right I have compared them all on typical out of pocket cost, whether there is insurance coverage, and how much research there is at this point supporting that the procedure is effective. That indicator on the dial is placed to the right for lots of research and to the left for fewer or lower quality studies.

Based on the recent research showing that steroid shots breakdown cartilage and don’t work as well as we once thought, they should be avoided. A hyaluronic acid is a reasonable option as it’s covered by insurance and doesn’t harm cartilage. PRP works better than HA in multiple studies, so if you have mild knee OA and don’t mind spending out of pocket, it’s a good bet. Knee stem cell procedures based on bone marrow seem to work better in patients with more severe arthritis and may push the need for knee replacement down the road. Finally, newer options like A2M or IRAP may also be options for less severe arthritis, but are more expensive than PRP and likely work about as well. Finally, there no data on exosomes, so I wouldn’t waste your money at this point.

The upshot? There are lots of different types of knee injections, everything from the stuff insurance covers to other things that aren’t covered. These days orthobiologics are the new kids on the block that you should consider.

(1) 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. doi: 10.1001/jama.2017.5283

(3) Strand V, McIntyre LF, Beach WR, Miller LE, Block JE. Safety and efficacy of US-approved viscosupplements for knee osteoarthritis: a systematic review and meta-analysis of randomized, saline-controlled trials. J Pain Res. 2015;8:217–228. Published 2015 May 7. doi:10.2147/JPR.S83076

(8) Centeno C, Sheinkop M, Dodson E, et al. A specific protocol of autologous bone marrow concentrate and platelet products versus exercise therapy for symptomatic knee osteoarthritis: a randomized controlled trial with 2 year follow-up. J Transl Med. 2018;16(1):355. Published 2018 Dec 13. doi:10.1186/s12967-018-1736-8

(9) Centeno C, Pitts J, Al-Sayegh H, Freeman M. Efficacy of autologous bone marrow concentrate for knee osteoarthritis with and without adipose graft. Biomed Res Int. 2014;2014:370621. doi:10.1155/2014/370621

(10) Berger D, Lyons N, Steinmetz, N. In Vitro Evaluation of Injectable, Placental Tissue-Derived Products for Interventional Orthopedics. Interventional Orthopedics Foundation Annual Meeting. Denver, 2015.

(11) Becktell L, Matuska A, Hon S, Delco M, Cole B, Fortier L. Proteomic analysis and cell viability of nine amnion-derived biologics. Orthopedic Research Society Annual Meeting, New Orleans, 2018.

(17) Hudetz D, Borić I, Rod E, et al. The Effect of Intra-articular Injection of Autologous Microfragmented Fat Tissue on Proteoglycan Synthesis in Patients with Knee Osteoarthritis. Genes (Basel). 2017;8(10):270. Published 2017 Oct 13. doi:10.3390/genes8100270

(18) Mautner K, Bowers R, Easley K, Fausel Z, Robinson R. Functional Outcomes Following Microfragmented Adipose Tissue Versus Bone Marrow Aspirate Concentrate Injections for Symptomatic Knee Osteoarthritis. Stem Cells Transl Med. 2019 Jul 21. doi: 10.1002/sctm.18-0285.

(20) Wang S, Wei X, Zhou J, et al. Identification of α2-macroglobulin as a master inhibitor of cartilage-degrading factors that attenuates the progression of posttraumatic osteoarthritis. Arthritis Rheumatol. 2014;66(7):1843–1853. doi:10.1002/art.38576

(24) Wang Y, Yu D, Liu Z, et al. Exosomes from embryonic mesenchymal stem cells alleviate osteoarthritis through balancing synthesis and degradation of cartilage extracellular matrix. Stem Cell Res Ther. 2017;8(1):189. Published 2017 Aug 14. doi:10.1186/s13287-017-0632-0

(26) Centeno C, Pitts J, Al-Sayegh H, Freeman M. Efficacy of autologous bone marrow concentrate for knee osteoarthritis with and without adipose graft. Biomed Res Int. 2014;2014:370621. doi:10.1155/2014/370621

(27) Centeno CJ, Al-Sayegh H, Bashir J, Goodyear S, Freeman MD. A dose response analysis of a specific bone marrow concentrate treatment protocol for knee osteoarthritis. BMC Musculoskelet Disord. 2015;16:258. Published 2015 Sep 18. doi:10.1186/s12891-015-0714-z

(32) Farr J1, Gomoll AH, Yanke AB, Strauss EJ, Mowry KC; ASA Study Group. A Randomized Controlled Single-Blind Study Demonstrating Superiority of Amniotic Suspension Allograft Injection Over Hyaluronic Acid and Saline Control for Modification of Knee Osteoarthritis Symptoms. J Knee Surg. 2019 Sep 18. doi: 10.1055/s-0039-1696672.

(34) Shen L, Yuan T, Chen S, Xie X, Zhang C. The temporal effect of platelet-rich plasma on pain and physical function in the treatment of knee osteoarthritis: systematic review and meta-analysis of randomized controlled trials. J Orthop Surg Res. 2017;12(1):16. Published 2017 Jan 23. doi:10.1186/s13018-017-0521-3

Category: Uncategorized

Therapeutic Injections for Knee Arthritis

Therapeutic knee injections can reduce painful symptoms related to knee osteoarthritis. Injections are often used in conjunction with other nonsurgical treatments—such as physical therapy, bracing or medications.

Knee injections typically deliver medicine directly inside the knee joint capsule. Ultrasound may be used to help guide placement of an injection.


Read more about the types of therapeutic injections for knee osteoarthritis
in the Arthritis-health Injections Health Center

This page describes different injections available, including cortisone, hyaluronic acid, platelet rich plasma (PRP), and stem cell injections, as well as prolotherapy. A physician and patient can discuss these options and decide which, if any, therapy is most appropriate.


Cortisone Injections for Knee Arthritis

Cortisone injections work by treating the inflammation that can cause knee pain, swelling, and warmth. The effects of a cortisone injection can last from 3 weeks to 3 months, and occasionally longer.

See Cortisone Injections (Steroid Injections)

People who want quick, temporary relief from knee arthritis pain may choose to have a cortisone injection. The temporary pain relief may allow a person to engage in physical therapy; attend to an important life event, such as a long-planned vacation; or postpone knee replacement surgery to a later, more convenient time.

See What to Know Before Getting a Cortisone Injection

Hyaluronic Acid Injections for Knee Arthritis

A hyaluronic acid injection delivers lubricating fluid into the knee joint. The goal is to temporarily lubricate the knee joint, thereby decreasing knee pain and inflammation, improving knee function, and perhaps even slowing the degeneration process.

See Hyaluronic Acid Injections for Knee Osteoarthritis

Generally, hyaluronic acid injections are slower to take effect than cortisone injections; however, the positive effects may last longer.

See Do Hyaluronic Acid Injections Work for Knee Osteoarthritis?

These injections are sometimes called viscosupplementation injections.

See Hyaluronic Acid Injection for Knee Osteoarthritis: Procedure and Risks

Platelet Rich Plasma Injections (PRP Injections) for Knee Arthritis

Platelet-rich plasma therapy attempts to take advantage of the blood’s natural healing properties to repair damaged tissue. It is derived from a sample of the patient’s own blood and contains higher concentration of platelets than is found in normal blood.

See Platelet-Rich Plasma (PRP) Therapy for Arthritis

There is growing evidence that suggests PRP injections may work to treat knee osteoarthritis in some people, but they remain controversial. PRP injections are not considered standard practice.

See Efficacy of Platelet-Rich Plasma Injections

Stem Cell Injections for Knee Arthritis

Researchers theorize that, when injected into to an osteoarthritic knee, stem cells might develop into cartilage cells; suppress inflammation; slow down cartilage degeneration; and/or decrease knee pain. The stem cells used in these injections are usually collected from the patient’s fat tissue, blood, or bone marrow.

See What Are Stem Cells?

Whether stem cell injections are effective in treating osteoarthritis is a controversial subject. Like PRP injections, stem cell injections are not considered standard practice.

See Stem Cell Therapy for Arthritis


Prolotherapy for Knee Arthritis


Prolotherapy typically involves 15-20 injections into the affected soft tissue. This image shows prolotherapy being administered to the knee’s patellar tendon. To treat knee osteoarthritis, prolotherapy injections may be made to other nearby tissues.

The goal of prolotherapy is to stimulate natural tissue repair in the body. During treatment, a physician will inject an irritant, such as a dextrose solution, into the arthritic knee joint and surrounding tissues. Several injections—perhaps 15 or 20—will be made during one treatment session.

Prolotherapy temporarily increases inflammation. The hope is that the additional inflammation will facilitate further healing.

Some clinical research studies suggest prolotherapy is effective in treating knee osteoarthritis,1,2 but these studies vary in quality. Prolotherapy is controversial and not considered standard practice.

Prolotherapy is not appropriate for most people with inflammatory forms of arthritis, such as rheumatoid arthritis or gout.

Your Guide to Injections for Knee Osteoarthritis

If oral medications aren’t easing your knee osteoarthritis pain, you may want to consider getting injections. iStock

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When osteoarthritis first starts to rear its (painful) head, you might be able to manage the symptoms by popping an anti-inflammatory medication, trying physical therapy, or finding ways to ease the cumulative stress that’s placed on your knees.

But because knee osteoarthritis worsens over time, it’s important to be aware of your symptoms and set up a treatment plan sooner rather than later. “There are no curative strategies for knee osteoarthritis,” says Scott C. Faucett, MD, an orthopedic surgeon at the Centers for Advanced Orthopaedics in Washington, DC. “For now, there are only management strategies.”

If you’re not ready to consider knee replacement surgery, but the pain, swelling, and stiffness are slowing you down, you might want to consider having injections into the osteoarthritic knee, Dr. Faucett says.

There are three types of injections that are currently supported by good quality studies, he says: cortisone shots, injection of hyaluronic acid (HA) supplements, and injection of platelet-rich plasma (PRP). Here is what to know about each type of injection.

Cortisone Injections for Knee Osteoarthritis

Cortisone (also called corticosteroid, or steroid) injections are the most common type of injections for the treatment of knee osteoarthritis. According to the Arthritis Foundation, the drug works like the natural hormone cortisol to change the body’s immune response and lower inflammation levels.

The injection, which is given directly into your knee joint, will work quickly to give you relief. “You’ll get an immediate response from the anesthetic,” says Faucett.

The anesthetic wears off in 12 to 24 hours, and the cortisone begins working within 24 to 72 hours. “If there’s a lot of swelling and pain, and a seemingly active inflammatory process, I tend to recommend cortisone because that will act relatively quickly for swelling,” Faucett says.

The effects of the shots typically last about two months, says the Arthritis Foundation, and people may need a cortisone shot every three to four months to keep inflammation at bay.

However, knee injections may not work for everyone. In a study published in the January 2017 issue of BMC Musculoskeletal Disorders, 61 percent of the people who received cortisone injections for knee osteoarthritis reported feeling less pain three weeks after the injection, and 46 percent continued to experience pain relief at nine weeks. Plus, there are possible side effects from these shots, according to the Arthritis Foundation, including:

  • Nerve damage
  • Bone thinning
  • Short-term joint irritation
  • Infection

The Arthritis Foundation also cautions that repeated cortisone injections may actually add to the breakdown of cartilage in the knee, accelerating the osteoarthritis process. Because of this risk, your doctor may limit the number of injections you should get.

William J. Bryan, MD, an orthopedic surgeon at Houston Methodist Hospital in Houston, says that frequent cortisone injections could accelerate osteoarthritis, but they also may slow down the progression of the condition by lowering inflammation in the joint.

Authors of a major review of studies published by the Cochrane Database of Systematic Reviews in October 2015 reported that, based on their analysis of 27 clinical trials comparing the effect of cortisone injections with fake (sham) injections or no intervention at all, steroid injections seem to offer a moderate improvement in pain and a small improvement in physical function for up to six weeks after the injection.

“I liken a cortisone shot for your osteoarthritic knee to a how you handle a fire,” Faucett says. “If you have a small trash-can fire, you can use a fire extinguisher and it won’t come back. But if it’s a large house fire, won’t keep it out for long.”

If you’ve already tried cortisone injections for a stiff or painful knee, or are in an arthritic phase with a very swollen knee, another option for you may be a procedure called joint aspiration. Faucett says that he often offers joint aspiration (which involves removing excess fluid) to, for example, people with “effusions,” some of which have grown to the size of a grapefruit.

Hyaluronic Acid Injections for Knee Osteoarthritis

If cortisone injections haven’t worked for you, you may want to consider having an injection of hyaluronic acid. In healthy joints, hyaluronic acid works like a lubricant and cushion, or shock absorber, says the Arthritis Foundation, and people with osteoarthritis may have experienced some breakdown of this fluid. HA injections aim to add a natural fluid back into the joint.

Typically, HA injections are given weekly for three to five weeks. Doctors first take out a little joint fluid to make space for the injection. Once injected directly into the knee, this component of synovial fluid can reduce inflammation, Faucett says.

While the injections don’t work as quickly as cortisone shots (it typically takes one or two weeks before you start to notice the effects, Faucett says), they can be paired with cortisone injections for a more immediate benefit. What’s more, the effects typically last longer than a cortisone shot — about six months, Faucett says. A review of overlapping meta-analyses published in September 2016 in Scientific Reports found that HA was both safe and effective at easing the symptoms of knee osteoarthritis and led to few side effects or unwanted reactions.

Platelet-Rich Plasma (PRP) Injections for Knee Osteoarthritis

Another option to consider is a PRP injection. Here’s how it works: A doctor will draw your blood in their office and separate your blood platelets, which are growth factors that may decrease inflammation. These platelets are then injected into the knee to help supplement the fluid there. In addition to calming inflammation, they may also help lubricate and cushion the joint.

Side effects of the treatment may include passing dizziness, headaches, and nausea, according to a February 2017 article published in the journal EFORT Open Review. Plus, PRP injections aren’t currently covered by insurance and therefore are more expensive than other options. This cost may be an issue for some people, says Stephen J. Nicholas, MD, director of the Nicholas Institute of Sports Medicine and Athletic Trauma at Lenox Hill Hospital in New York City. Each injection may cost about $500 to $1,000 or more, and they’re typically given as a series of three shots.

“There’s not enough head-to-head evidence to support ,” says Faucett. The choice comes down to other factors specific to you, so it’s important to talk things through with your doctor.

Both are relatively expensive compared with cortisone shots, Dr. Bryan adds, but some people choose PRP because its effects tend to last a little longer and they’re attracted to the idea of using their own healing proteins to get relief.

What’s Next for Treating Knee Osteoarthritis?

“As of now, these are the options we have for managing the inflammation and pain of knee osteoarthritis,” Faucett says. In the future, “there hopefully will be some new types of biologic treatments — and there are some Food and Drug Administration studies on stem cell injections for this condition.”

For now, read up on your options and discuss them with your doctor — especially if your current therapy is no longer working for you.

If you’re one of the 30 million adults in the United States who suffer with joint pain, you know the pain often is debilitating. It can keep you from staying active and even make daily chores seem impossible. What you might not know is that your doctor can treat you with more than pills or surgery.

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Depending on the severity of your pain, injections can be another option for easing your joint pain and get you moving again, says physiatrist Michael Schaefer, MD.

“We use these injections to try to reduce inflammation and pain in your joints,” Dr. Schaefer says. “With these treatments, you often can experience fewer symptoms for several months.”

There are several injectable options to help treat knee pain, says sports and medical orthopaedist Jason Genin, DO.

“The injections range from corticosteroids, which have been around for decades, to newer orthobiologic injections like platelet-rich plasma (PRP) and placental tissue matrix (PTM),” he says.

Your physician will decide which one is best based on your individual needs, says sports and medical orthopaedist Dominic King, DO.

“Not every injection is right for every patient,” Dr. King says. “We take a lot of time to understand your specific issues and create an injectable plan that works with your entire knee care path.”

Corticosteroid injections

Use: This injection is the first line of defense against osteoarthritis symptoms and other joint pain in shoulders, knees and hips, Dr. Schaefer says. Corticosteroids can offer relief for two to three months, and reduce inflammatory cell activity in the joint.

Side effects: As with all injections, there’s a small chance of infection — about one in 1,000.

Hyaluronic acid injections

Use: Hyaluronic acid (HA) injections often are used when corticosteroid injections don’t work. But they usually are approved only for use in the knee.

In some instances, doctors consider an HA injection first if you don’t have obvious signs of inflammation. HA also is a better option if you have diabetes, as corticosteroids can raise blood sugar levels.

Also known as gel injections, HA injections are chemically similar to your natural joint fluid.

When you have osteoarthritis, joint fluid becomes watery. So, this injection helps to restore the fluid’s natural properties and works as a lubricant and a shock absorber.

“HA is a cushion or a buffer against inflammatory cells in the joint,” Dr. Schaefer says. “In some cases, it can stimulate the knee to start producing more natural HA.” Some physicians also believe that HA helps reduce pain by coating nerve endings within the joint.

One treatment, which may consist of between one and three injections, usually offers symptom relief for four to five months, but sometimes up to one years. However, pain and stiffness will return. Most insurance companies only approve one HA injection every six months.

Side effects: There’s a 1-in-100 chance of an inflammatory reaction, Dr. Schaefer says. However, this reaction is less common with the newer HA injections.

Platelet-rich plasma (PRP) injections

Use: Platelet-rich plasma (PRP) injections can treat osteoarthritis joint pain, and are being thoroughly researched to understand their effects, Dr. King says.

These injections use your own blood and platelets to promote healing. Platelets contain growth factors and proteins that aid healing in soft tissues. Research shows PRP injections can alter the immune response to help reduce inflammation, Dr. Schaefer says.

Side effects: Side effects include a very low risk of infection and pain at the injection site. You must stop oral anti-inflammatory medications for a short amount of time if you get a PRP injection, Dr. Genin says.

Placental tissue matrix (PTM) injections

Use: Placental Tissue Matrix (PTM) injections can very profoundly decrease the pain related to osteoarthritis, Dr. King says.

These are injections of placental tissue, which is obtained after a healthy baby is delivered from a healthy mother. Research has discovered that there is a large number of growth factors in placental tissue that promote healing, Dr. Genin says.

Side effects: Side effects include a very low risk of infection and pain at the injection site. The placental tissue is “immune privileged,” which means the body would not have an adverse reaction to it.

Many of these injections often are effective in reducing or stopping your joint pain, but it’s important to remember that they may not keep the pain from returning, Dr. Schaefer says. In fact, they’re most effective when used with other therapies.

“We consider surgical options and stronger medications only if other treatment options have failed,” he says. “But weight loss, physical therapy and bracing also go a long way toward relieving pain.”

Injections for Knee Osteoarthritis Video

Treating knee osteoarthritis is, basically, we can break it down into two components. There’s reducing the inflammation within the knee, and then there’s getting all of the muscles and the biomechanics right to take the pressure off of the knee so that the same forces aren’t going through it so the inflammation doesn’t re-accumulate.

When the pain’s not getting better with physical therapy, or if the pain is interfering with the person’s ability to participate with physical therapy, one, there are oral medications to help with the pain—they’re not going to fix anything but they can certainly help with the symptoms. And also there are different kinds of injections that one can do in order to take away the pain and inflammation from the arthritis.

The two broad categories. One is steroids. You can put steroids into the knee, which are certainly not going to fix the arthritis in the knee but they will open up a window of opportunity during which a person can take advantage of not having the pain in the knee in order to stretch, and strengthen, and be more active, lose the weight, and tweak the biomechanics, in essence, so that the pain doesn’t come back in three or six months because the mechanics have been shifted so the same forces aren’t going through the knee.

The other broad category of injections are hyaluronic acids. This is basically like putting an oil change into the knee, right? Hyaluronic acid is basically joint fluid. What happens in arthritis of the knee is that you start to lose some of the joint fluid. And what the pharmaceutical companies have done is they’ve created a synthetic joint fluid that you can put back into the knee through a series of injections. Depending on the brand that you use, it’s either one, or three, or four, or five injections series that you do.

What this is sort of like, it’s sort of like paving the potholes in the road. If you think of arthritis as sort of potholes in the road, this just puts a coat over it, it lubricates it. Again, you’re not fixing the arthritis; the injections do wear off over a period of typically six months. But if you use that time, if you use the time when the pain is better and the inflammation is down again as a window of opportunity during which you can stretch, and strengthen, and affect the biomechanics, then ideally as the medications wear off, the pain won’t come back because the mechanics have been tweaked.

Hyaluronic acid injections are used to treat knee osteoarthritis and improve the functions of the knee joint. This treatment method is called viscosupplementation.

See Knee Osteoarthritis Treatment

During a hyaluronic acid injection (viscosupplementation), a small amount of hyaluronic acid, often just 2 mL, is injected directly into the knee joint capsule.1

Watch: Knee Anatomy Video

The goals of treating knee osteoarthritis with hyaluronic acid injections are to:

  • Reduce pain
  • Improve joint movement by increasing joint lubrication and reducing joint friction and inflammation
  • Perhaps slow osteoarthritis progression

Hyaluronic acid injections are usually given at a doctor’s office. Depending on the brand used, this treatment involves 1, 3, 4, or 5 injections. If more than one injection is needed, injections are given one week apart.2


What Does Hyaluronic Acid Do in the Knee Joint?


In the osteoarthritic knee, the quality and quantity of hyaluronic acid in the joint fluid reduces; causing pain, stiffness, and swelling in the joint. Read What Is Hyaluronic Acid?

A healthy knee joint contains up to 4 mL of joint fluid.3 Hyaluronic acid is a key component of the joint fluid. It gives the joint fluid its viscous, slippery quality, which does the following:

  • Enables the bones’ cartilage-covered surfaces to glide against each other, thereby reducing joint friction
  • Adds cushion to protect joints during impact (e.g. weight-bearing activity)

See Knee Anatomy

Joints affected by osteoarthritis typically have a lower concentration of hyaluronic acid in their joint fluid than healthy joints, and therefore less protection against joint friction and impact.4 Experts believe this further accelerates the joint degeneration process, setting in place a vicious cycle.

In This Article:

  • Hyaluronic Acid Injections for Knee Osteoarthritis
  • Do Hyaluronic Acid Injections Work for Knee Osteoarthritis?
  • Hyaluronic Acid Injection for Knee Osteoarthritis: Procedure and Risks

Who Can Get Hyaluronic Acid Injections for Knee Osteoarthritis?

Hyaluronic acid injection is not a first-line treatment for knee osteoarthritis.5 This treatment may be considered for those who:

  • Have moderate knee osteoarthritis with symptoms that affect daily living.6-7

    See Knee Osteoarthritis Symptoms

  • Do not take pain medication because they:
    • Have little or no benefit from pain relieving medications, such as non-steroidal anti-inflammatory drugs (NSAIDs), and/or steroids (tablets or injectable).4-5 Some people may also choose to avoid these medications.
    • Are at a risk of side effects such as kidney damage, heart problems, and/or abdominal bleeding with long-term use of NSAIDs.5,6,8
    • Have other conditions, such as diabetes or high blood pressure, and cannot take medications such as steroids.

    See Pain Medications for Arthritis Pain Relief

  • Show improvement after the first round of treatment. Such cases may benefit from additional hyaluronic acid injections when the osteoarthritis symptoms reappear.5-6
  • Are not eligible for surgery, want to postpone surgery, or do not want to have surgery.

    See Types of Knee Surgery for Arthritis Treatment

While people of any age can get hyaluronic acid injections, this treatment may be more effective in people under 65 years of age.2


When Are Hyaluronic Acid Injections Not Appropriate?

Hyaluronic acid injections may not be appropriate in some people, including, but not limited to:

  • Women who are pregnant or breast-feeding.2
  • Children and adolescents.2
  • Those with bacterial and other infections in and/or around the osteoarthritic knee.2
  • Those with a known allergy to hyaluronate products.2

Additionally, those who are allergic to eggs or other bird products (e.g. poultry) are advised to inform their doctor.4 This is because certain hyaluronate products are made from rooster combs and may not be suitable for such patients.

Questions to Ask When Choosing Hyaluronic Acid Injection Treatment for Knee Osteoarthritis

While deciding to choose hyaluronic acid injections for the knee, it may help to ask the doctor a few questions regarding the treatment. Asking relevant questions will help weigh the potential risks and benefits of these injections and set reasonable expectations.

A few examples of questions that can be asked are:

  • What is the typical outcome for a patient like me?
  • Will there be an immediate reaction in my knee after the injection?
  • What are the risks associated with this injection?
  • How long will my recovery be?
  • Is it recommended to take time off work?
  • How might this injection affect the chances of postponing my knee replacement surgery?
  • Do I need to do anything to prepare for the injection?
  • What other treatments can be considered?

By asking these questions, patients can discuss concerns specific to their health and lifestyle and make the necessary adjustments for a better treatment outcome.

  • 1.Abate M, Vanni D, Pantalone A, Salini V. Hyaluronic acid in knee osteoarthritis: preliminary results using a four months administration schedule. International Journal of Rheumatic Diseases. 2015;20(2):199-202. doi:10.1111/1756-185x.12572
  • 2.Hunter DJ. Viscosupplementation for Osteoarthritis of the Knee. Jarcho JA, ed. New England Journal of Medicine. 2015;372(11):1040-1047. doi:10.1056/nejmct1215534
  • 3.Kraus VB, Stabler TV, Kong SY, Varju G, McDaniel G. Measurement of synovial fluid volume using urea. Osteoarthritis Cartilage. 2007;15(10):1217-20.
  • 4.Altman RD, Manjoo A, Fierlinger A, Niazi F, Nicholls M. The mechanism of action for hyaluronic acid treatment in the osteoarthritic knee: a systematic review. BMC Musculoskelet Disord. 2015;16:321. Published 2015 Oct 26. doi:10.1186/s12891-015-0775-z
  • 5.Cooper C, Rannou F, Richette P, et al. Use of Intraarticular Hyaluronic Acid in the Management of Knee Osteoarthritis in Clinical Practice. Arthritis Care Res (Hoboken). 2017;69(9):1287-1296.
  • 6.Maheu E, Rannou F, Reginster JY. Efficacy and safety of hyaluronic acid in the management of osteoarthritis: Evidence from real-life setting trials and surveys. Semin Arthritis Rheum. 2016;45(4 Suppl):S28-33.
  • 7.Henrotin Y, Raman R, Richette P, et al. Consensus statement on viscosupplementation with hyaluronic acid for the management of osteoarthritis. Seminars in Arthritis and Rheumatism. 2015;45(2):140-149. doi:10.1016/j.semarthrit.2015.04.011
  • 8.Smith C, Patel R, Vannabouathong C, et al. Combined intra-articular injection of corticosteroid and hyaluronic acid reduces pain compared to hyaluronic acid alone in the treatment of knee osteoarthritis. Knee Surgery, Sports Traumatology, Arthroscopy. July 2018. doi:10.1007/s00167-018-5071-7

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