Joint pain, especially that stemming from conditions like osteoarthritis, often requires targeted interventions to restore comfort and mobility. When non-prescription pain relievers and physical therapy are not enough, doctors frequently turn to injections delivered directly into the affected joint space. The two most common types are cortisone shots and gel shots, but they function on entirely different biological principles and treat distinct aspects of joint disease. Understanding the fundamental distinction between these two injections is important because they treat different aspects of joint disease.
Cortisone Injections: Targeting Inflammation
Cortisone shots introduce a powerful anti-inflammatory medication directly into the site of pain, most commonly using a synthetic corticosteroid like triamcinolone or methylprednisolone. This substance mimics the effects of cortisol, a hormone naturally produced by the body’s adrenal glands, to quickly suppress the immune response and reduce swelling. The primary function of a cortisone injection is to interrupt the inflammatory cascade, which is responsible for much of the acute pain and swelling in conditions such as bursitis, tendinitis, or an arthritis flare-up.
When injected into the joint, the corticosteroid inhibits the production of inflammatory molecules, such as prostaglandins and cytokines, minimizing redness, heat, and pain. This mechanism is designed to provide rapid relief, with some patients feeling noticeable improvement within hours to a few days after the procedure. To further enhance the immediate effect, the steroid is often combined with a fast-acting local anesthetic, like lidocaine, which offers instant but temporary numbing. Because the medication targets inflammation, it is a preferred treatment for acute, highly inflamed joints.
Viscosupplementation (Gel Shots): Restoring Joint Fluid
The treatment commonly referred to as a “gel shot” is medically termed viscosupplementation, and it involves injecting hyaluronic acid (HA) into the joint. HA is a naturally occurring component of synovial fluid, the thick, clear liquid that lubricates and cushions healthy joints. In an osteoarthritic joint, the natural HA degrades and thins, which reduces the joint fluid’s ability to absorb shock and causes painful friction between the bones.
The injected HA acts as a supplement, restoring the viscous, gel-like quality of the synovial fluid to improve joint lubrication and shock absorption. This process aims to treat the mechanical wear and tear associated with joint degeneration, rather than targeting acute inflammation. Unlike cortisone, the full benefits of viscosupplementation are not immediate and can take several weeks. The goal is to improve the joint’s environment, promoting better mobility and reducing pain over time.
Key Differences in Treatment Frequency and Longevity
The practical application of these injections differs significantly in terms of onset, duration, and safe administration frequency. Cortisone shots offer a quick onset of action, with pain relief typically starting within a few days. However, the relief is generally shorter-lived, lasting anywhere from a few weeks to up to three months.
Because corticosteroids can weaken local tissues and cartilage with repeated use, the frequency is strictly limited, often to no more than three or four times per year in a single joint. Viscosupplementation provides a much slower onset, sometimes taking four to twelve weeks to reach its peak benefit. Once effective, the pain relief from a gel shot commonly lasts six months or more. Gel shots are often given as a series of one to five injections and can generally be repeated every six months.
Comparing Side Effects and Patient Selection
The risk profiles and ideal patient candidates for each injection type are distinct. Cortisone injections carry the risk of a temporary “cortisone flare,” where pain worsens for a day or two before the anti-inflammatory effect begins. Repeated use of cortisone is associated with local tissue weakening, including tendons, and can potentially accelerate cartilage damage. Cortisone can also temporarily raise blood sugar levels, requiring monitoring in patients with diabetes.
Viscosupplementation typically has a milder side effect profile, with the most common reaction being temporary localized pain or swelling at the injection site. Cortisone is generally reserved for patients experiencing acute, significant inflammation, such as a severe arthritis flare. Conversely, gel shots are favored for the long-term management of chronic pain caused by joint friction and degeneration, particularly in mild to moderate knee osteoarthritis.