“Chicken shots” is a colloquial name for hyaluronic acid injections given in the knee to treat osteoarthritis pain. The medical term is viscosupplementation. They picked up the nickname because the hyaluronic acid in most formulations is derived from rooster comb tissue, the fleshy red crest on top of a rooster’s head. You might also hear them called “rooster comb shots,” “gel injections,” or simply “knee gel shots.”
Why They’re Called Chicken Shots
Hyaluronic acid is a thick, gel-like substance your joints produce naturally. It acts as both a lubricant and a shock absorber inside the joint capsule. In osteoarthritis, the concentration and quality of this natural fluid breaks down, leaving cartilage surfaces grinding against each other with less cushioning.
To replace what’s been lost, manufacturers extract and purify hyaluronic acid (technically sodium hyaluronate) from rooster comb tissue, which is rich in the compound. That avian origin is the entire reason for the nickname. Some newer formulations use a bacterial fermentation process instead, but most products on the market still trace back to rooster combs.
How These Injections Work
Viscosupplementation does more than just add lubrication. The injected gel increases the viscosity of synovial fluid, reduces friction between cartilage surfaces, and absorbs pressure and vibration that would otherwise damage the joint. Think of it as restoring the cushion your knee has lost over years of wear.
Beyond the mechanical benefits, the injections also reduce inflammation by lowering levels of inflammatory molecules inside the joint. They have a direct pain-relieving effect too: hyaluronic acid quiets the nerve fibers that send pain signals from the joint, raising the threshold for what triggers discomfort during movement. So while the nickname makes them sound simple, the injections work on multiple levels at once.
What the Procedure Looks Like
The treatment is done in a doctor’s office. A needle delivers the gel directly into the knee joint, sometimes guided by ultrasound. Depending on the product used, you’ll receive anywhere from a single injection to a series of three to five weekly injections. Some formulations, like Synvisc-One, Durolane, and Monovisc, are designed as a single-shot treatment. Others, like Hyalgan and Supartz FX, require multiple visits.
Pain relief doesn’t kick in immediately. Most people start noticing improvement a few weeks after the series is complete. When the injections work well, relief can last six months or longer. In a large study of over 1,800 patients with severe knee osteoarthritis, 75% of those who received viscosupplementation delayed knee replacement surgery by seven years or more.
Who Gets Them
These injections are FDA-approved specifically for osteoarthritis of the knee. They’re considered a second-line option, meaning you’d typically try other approaches first: over-the-counter pain relievers, physical therapy, weight loss if relevant, and supportive devices like knee braces. If those measures haven’t provided enough relief over roughly three months, viscosupplementation becomes a reasonable next step.
Medicare and most insurers cover the injections for knee osteoarthritis, but the diagnosis needs to be confirmed with an X-ray, and your medical records must show that conservative treatments were tried first. If you go back for repeat courses, your records need to demonstrate that the previous round actually helped.
How Well They Work
Results vary by individual. In clinical trials, patients experienced roughly a 32-point reduction on a standard 100-point pain scale at six months. When viscosupplementation was combined with physical therapy, bracing, and patient education, pain scores dropped by about 60%. The injections tend to work best for mild to moderate osteoarthritis, though even patients with severe disease have benefited enough to postpone surgery for years.
Not everyone responds. Some people get dramatic relief, while others notice little difference. The variation partly depends on how advanced the joint damage is, which specific product is used, and whether the injections are paired with exercise and other supportive measures.
Side Effects and Precautions
The most common side effects are temporary: joint stiffness, muscle soreness, and pain at the injection site. Some people experience swelling or redness in the knee for a day or two after the shot. Less commonly, the injection site may develop bruising, warmth, or a rash.
Because many formulations come from rooster combs, anyone with a known allergy to poultry or avian proteins should flag this before treatment. Bacterially derived products like Euflexxa offer an alternative for those patients, though people with allergies to bacterial proteins need to avoid those versions instead. The injections should not be given if you have an active skin or joint infection in the area.
Available Brands
There are currently 12 FDA-approved viscosupplementation products in the United States. Some of the more widely used names include Synvisc, Synvisc-One, Hyalgan, Euflexxa, Orthovisc, Supartz FX, Monovisc, and Durolane. They differ in concentration, injection volume, and how many shots make up a full course, but the active ingredient in all of them is some form of hyaluronic acid. Your doctor’s recommendation will often depend on insurance coverage, dosing convenience, and personal experience with a particular product.