Knee osteoarthritis (OA) is a common condition, affecting an estimated 19% of men aged 60 and older. The symptoms of OA, including pain, stiffness, swelling, tenderness, and limited range of motion, can significantly impact daily life, making simple tasks feel challenging. While many people can manage these symptoms with lifestyle changes such as weight loss, physical therapy, and targeted exercises, for others, additional interventions may be needed. One of the most common approaches to managing knee OA pain is through injections, which can provide temporary relief, but they come with limitations.
Knee injections are often recommended when more conservative treatments, such as physical therapy or pain medications, fail to provide sufficient relief. Rheumatologist Dr. Robert Shmerling, a former clinical chief of rheumatology at Harvard-affiliated Beth Israel Deaconess Medical Center, explains that injections can offer immediate pain relief, reduce inflammation, and improve mobility. However, he stresses that injections are not a permanent solution for osteoarthritis.
“These injections may help in the short term, but they don’t cure knee OA or stop its progression,” says Dr. Shmerling. “If you find yourself needing repeated injections to manage pain and maintain mobility, it may be time to consider more long-term solutions, such as knee replacement surgery.”
There are two main types of injections commonly used to treat knee OA: corticosteroid injections and hyaluronic acid injections.
Corticosteroid injections, also known as steroid shots, are often the first treatment option for knee OA. These injections contain synthetic versions of cortisol, a hormone produced by the adrenal glands that helps reduce inflammation. When injected into the knee joint, corticosteroids can alleviate pain, reduce swelling, and improve overall knee function.
Before administering the injection, the doctor typically numbs the area with a local anesthetic. If there is significant swelling, they may first remove excess fluid from the knee to reduce pressure. “By removing the excess fluid, we help relieve swelling, which makes the steroid injection more effective,” Dr. Shmerling explains.
The corticosteroid itself usually takes 24 hours to start working, though the numbing agent provides immediate relief. While the injection can provide significant pain relief, it is important to remember that the effects are temporary. Relief can last from a few weeks to several months, but repeated injections may become less effective over time. In some cases, they may even contribute to further joint deterioration if used too frequently.
For individuals who don’t respond well to corticosteroids or who may have underlying conditions like diabetes, hyaluronic acid injections offer an alternative. Hyaluronic acid is a natural component of the synovial fluid in the joints, which serves as a lubricant, allowing for smoother movement and reducing friction. As osteoarthritis progresses, the body’s production of hyaluronic acid decreases, leading to thinner synovial fluid and increased pain and stiffness.
“Hyaluronic acid injections act like oil on a rusty joint,” says Dr. Shmerling. “They help restore the lubrication that’s lost due to the progression of OA.” These injections can improve joint mobility and reduce discomfort, although, like corticosteroid injections, their effects are temporary. They may be used when steroid shots aren’t effective or when there are concerns about side effects from corticosteroids, such as increased blood sugar levels in diabetic patients.
While knee injections can offer significant relief from the pain and swelling associated with osteoarthritis, they are not a cure. The primary benefit of these injections is their ability to provide fast, short-term relief, helping patients maintain mobility and improve quality of life. However, they are not a long-term solution, and over-reliance on them may lead to diminished effectiveness and potential joint damage.
If knee injections fail to provide lasting relief or if the frequency of injections increases, it may be time to consider more permanent options like knee replacement surgery. Always consult with a healthcare provider to determine the best course of treatment based on your symptoms, health history, and overall goals for pain management.
