Cortisone Shot, Gel Injection or PRP: How They Differ

Cortisone Shot, Gel Injection or PRP: How They Differ

If you have a painful joint, you may be offered a cortisone shot, a gel injection or PRP, and the three are easy to mix up. A cortisone shot is a steroid medicine that quiets inflammation, a gel injection adds hyaluronic acid to the fluid inside the knee, and PRP is a concentrate of platelets made from your own blood at the visit.

They differ in what is injected, where it comes from, how often it can be given, the side effects to watch for and how insurance treats it.

At PRIME Orthopedics & Regenerative Center, all three injections are given by Dr. Abbasi, who is double board certified in Orthopedic Surgery and Sports Medicine, after a full orthopedic examination.

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What Is a Cortisone Shot?

A cortisone shot, also called a steroid injection or corticosteroid injection, is an injection of a manufactured steroid medicine into a joint, a bursa or the sheath around a tendon. Cortisol is a hormone the adrenal glands make every day, and one of its jobs is to keep inflammation in check. The medicines in a cortisone shot are laboratory-made relatives of cortisol, designed to act more strongly and to stay where they are placed.

So yes, a cortisone shot is a steroid. It is a corticosteroid, the anti-inflammatory kind, and not the anabolic steroids associated with muscle building.

What Is in a Cortisone Shot

A cortisone shot usually contains two medicines in one syringe:

• The Steroid. The steroid is most often triamcinolone or methylprednisolone; betamethasone and dexamethasone are also used.
• The Anesthetic. A local anesthetic such as lidocaine or bupivacaine is mixed in, so the area goes numb within minutes of the injection.

Cortisone shots are given in many places in the body, including the shoulder, elbow, wrist, hip, knee and ankle. A cortisone shot in the knee and a cortisone shot in the shoulder are among the most common. They are used for Arthritis, Bursitis, Carpal Tunnel Syndrome and back pain, among other conditions.

How a Cortisone Shot Works

Inflammation is the body's response to irritation or injury. Cells in the area release chemical signals, such as prostaglandins and cytokines, that bring in fluid and immune cells, and those signals are a large part of what makes an inflamed joint swollen, warm and painful.

A corticosteroid enters the cells in the area and switches down the production of those signals. Injected into a joint, the steroid settles on the joint lining, the synovium, where the lining cells and the immune system together drive much of a joint's inflammation. The numbing medicine acts within minutes; the steroid acts more slowly.

Because the medicine is placed where it is needed, only a small amount reaches the rest of the body. That is why whole-body effects of steroid tablets, such as weight gain or loss of bone density, are rare after a single injection.

Cortisone Shot Side Effects

Most cortisone shot side effects are short-lived, and a few are the reason doctors limit how often the injections are given.

• A Cortisone Flare. Some people have a day or two of increased pain and swelling after the injection, known as a cortisone flare or steroid flare.
• Higher Blood Sugar. A small amount of steroid escapes the joint, and in people with Diabetes it can raise blood sugar for several days. A clinical summary in American Family Physician (2023) found that in people with well-controlled Type 2 Diabetes, blood sugar peaked anywhere from 2 to 84 hours after an injection into a joint and returned to its usual level within 18 hours to 21 days. The first three days call for the closest watch.
• Facial Flushing. Some people notice a warm, red face for a short time after the injection.
• Skin Changes. The skin and the soft tissue beneath it can thin around the injection site, and the skin there can turn lighter in color. These effects are more likely with larger doses and more frequent injections.
• Cartilage. Steroids have a harmful effect on chondrocytes, the cells that maintain the smooth joint surface, and the American Academy of Orthopaedic Surgeons (AAOS) notes that cortisone injections over time can speed the progression of Arthritis.
• Tendons. The AAOS advises that a cortisone shot generally not be used for Tendinitis, because it can raise the chance of a tendon rupture, especially of the biceps, patellar and Achilles tendons.
• Infection. Any injection into a joint carries a small risk of infection, which is why the skin is cleaned and the injection is given with sterile technique. A hot, red, increasingly painful joint after an injection needs a call to the office the same day.

How Often You Can Have a Cortisone Shot

There is no formal limit on the number of cortisone shots a person can receive. In practice, according to the AAOS, doctors and other providers often set a limit of three to four cortisone shots a year.

Two situations call for more caution:

• Before a Joint Replacement. If a joint has had a steroid injection, the AAOS advises that a replacement of that joint be delayed at least three months, to lower the risk of infection after the operation.
• Before Cartilage Surgery. Before a cartilage procedure, such as microfracture or the implantation of a patient's own cartilage cells, a surgeon may limit or rule out cortisone shots in that joint.

What Is a Gel Injection for the Knee?

A gel injection for the knee, also called a gel shot, a hyaluronic acid injection or viscosupplementation, adds hyaluronic acid to the fluid inside the knee. Visco gel injection is another name for the same thing.

Hyaluronic acid is a natural substance in the synovial fluid that fills every joint. It gives the fluid its thick, slippery consistency, so the joint surfaces glide over each other, and it helps the fluid act as a shock absorber under load. In a knee with Osteoarthritis, the fluid usually holds less hyaluronic acid than normal, and the fluid is thinner. Viscosupplementation is designed to add back some of that lubricating, cushioning gel.

Gel shots were first used in Europe and Asia and became available in the United States in 1997. They are a knee treatment: the products are labeled for the knee, and insurers that cover them cover the knee. In the United States, gel shots are regulated as medical devices rather than as drugs.

Gel Shot Brands: One Shot or a Series

Patients are often told the name of a gel shot rather than what it is. The products differ in three ways: the number of injections in a course, the source of the hyaluronic acid, and the form of the gel, since some products link the molecules chemically into a thicker gel. The number of injections below is the regimen on each product's label, as listed in Aetna's policy on viscosupplementation.

• Single Injection. Synvisc-One, Gel-One, Durolane, Monovisc and Hymovis One are each given as one injection.
• A Short Series. Hymovis is given as two injections a week apart, and Synvisc, Euflexxa, Gelsyn-3, TriVisc, Visco-3 and Triluron as three weekly injections. Orthovisc is given as three or four weekly injections.
• A Longer Series. Hyalgan, Supartz FX and GenVisc 850 are given as five weekly injections.

The source matters for anyone with an allergy. Synvisc, Synvisc-One, Gel-One, Hyalgan and Supartz FX are made from hyaluronic acid extracted from chicken combs, and their labels caution against use in people allergic to avian (bird) proteins, feathers or eggs; the Gel-One label adds cinnamon. Euflexxa, Gelsyn-3, GenVisc 850, Hymovis, Monovisc, Orthovisc and Durolane are made by bacterial fermentation and contain no bird protein.

How a Gel Shot Is Given, and Aftercare

A gel shot is given into the knee joint through a fine needle. If the knee is swollen, excess fluid is often drawn off first, usually through the same needle, before the gel is injected.

Normal walking is fine after a gel injection. For the first 48 hours, the AAOS advises avoiding strenuous activity such as jogging or heavy lifting, and the Gel-One label adds long periods of standing, such as more than an hour on your feet.

Gel Knee Injection Side Effects

The most common side effects are pain, warmth and slight swelling in the knee right after the injection, and they usually settle on their own. Rarely, the knee fills with fluid and becomes red, warm and painful within a day or two; that reaction needs a call to the office straight away. Infection and bleeding into the joint are very rare.

How PRP Is Different

PRP (Platelet-Rich Plasma) is the one injection of the three that is not a manufactured product. It is prepared from a small draw of your own blood, which is spun in a centrifuge in the office to separate the platelets from the red blood cells. The result is a concentrate with several times the platelets of ordinary blood, carried in plasma. Some preparations keep the white blood cells (leukocyte-rich PRP) and some remove most of them (leukocyte-poor PRP).

Platelets store growth factors, proteins the body uses as signals in its normal response to an injury, and PRP is designed to deliver them in concentrated form to the joint or tendon being treated. A PRP gel injection is not a gel shot: PRP is a liquid concentrate of platelets and contains no hyaluronic acid. What Is PRP Therapy? explains how it is made in more detail.

A few practical points set PRP apart:

• The Schedule. There is no single standard schedule for PRP. The practice's typical protocol is one to three injections, depending on the size of the joint and the patient's response.
• Anti-Inflammatory Medicines. Because PRP works with the body's own early inflammatory response, we recommend avoiding anti-inflammatory medicines such as ibuprofen and naproxen, and ice, around the injection where possible.
• Soreness. The AAOS describes soreness at the injection site for up to a week or two. In our experience, the soreness is worst in the first few minutes and eases quickly, and most patients return to full activity the next day.

How the Three Are Given

All three are given with a needle, into a joint or around a tendon. The skin is cleaned, the area may be numbed first, and most people feel pressure as the medicine goes in. A cortisone or gel injection itself takes a few minutes; PRP takes longer, because the blood is drawn and prepared first. Where it helps, the injection can be guided by ultrasound, which shows the joint or tendon and the needle on a screen.

How Insurance Treats Each

Insurance treats the three injections differently.

• Cortisone Shots. A cortisone shot is a provider-administered medicine, and it is usually billed to insurance. Under Medicare Part B, the patient generally pays 20 percent of the Medicare-approved amount after the Part B deductible.
• Gel Shots. Medicare and many commercial insurers cover gel shots for Osteoarthritis of the knee when their criteria are met. Those criteria commonly include X-ray evidence of Osteoarthritis, at least three months of other treatment first, and a steroid injection tried first or ruled out; a repeat course is not paid sooner than six months after the last. Florida Blue's commercial policy, by contrast, states that hyaluronic acid injections into a joint do not meet its definition of medical necessity.
• PRP. Medicare's contractor for Florida, First Coast, considers PRP outside Medicare's national rule for certain wounds not reasonable and necessary, and Florida Blue, UnitedHealthcare, Cigna and Aetna classify PRP as experimental, investigational or unproven, or not medically necessary. Does Insurance or Medicare Cover PRP and Stem Cell Therapy? sets out each policy.

What Your Visit Involves

A complete orthopedic diagnosis before any treatment is recommended.

1. The Examination. The visit begins with an examination by Dr. Abbasi.
2. Your Imaging. Any imaging you bring, such as X-rays or an MRI, is reviewed at the same visit.
3. A Plan. The visit ends with a straight conversation about what your joint actually needs. Many people leave with a plan that involves no procedure at all.

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