Knee arthritis injections: Options for pain relief

After many years of wear and tear, knee pain often becomes more common as we get older. Most knee pain in people over 50, unless caused by a sudden injury, is due to osteoarthritis — a gradual thinning of cartilage within the knee joint. Cartilage allows the bones to smoothly glide across each other. As the cartilage layer thins or becomes pock-mocked, the joint surface can become inflamed from the friction, leading to stiffness and pain.

“When a person has a pain flare-up, ideally, the body’s immune system calms it down on its own with time and rest,” says Jason Lippman, MD, with MultiCare Orthopedics & Sports Medicine – Good Samaritan. “Oral medications and physical therapy can also help settle the irritation.”

But when time, rest, physical therapy or anti-inflammatory medicines don’t help relieve chronic pain, injectable therapy might be the next step.

“With targeted injections, we put a medication directly inside the joint,” explains Dr. Lippman. “This has a direct impact on bone and cartilage surfaces and other tissues involved in chronic pain and the inflammatory process.”

If there isn’t a structural injury that requires surgery, trying an injection is a reasonable approach to managing pain.

The three most common injection options

1. Corticosteroid injections

Liquid corticosteroid injections, often known as cortisone shots, are the most well-known, longest-standing type of injection. These anti-inflammatory medicines are injected directly in the knee joint to reduce inflammation.

They are fast-acting, often providing relief within days, but they are also the shortest lasting. These injections typically keep the knee comfortable for about six to 12 weeks, though some people feel comfortable longer.

By suppressing inflammation, corticosteroids switch off immune activity in the joint space.

“We don’t want to do these too often, as we want to give time for the medication to leave the joint and allow the normal immune surveillance of the joint to return,” Dr. Lippman adds. “They shouldn’t be done more frequently than about three times per year.”

Cortisone shots are usually the least expensive option, and they are commonly covered by insurance.

2. Hyaluronic acid injections

Hyaluronic acid is a naturally occurring substance in joint fluid that acts as a lubricant and support for knee joint cartilage. For those with osteoarthritis, hyaluronic acid can be injected inside the knee joint to help maintain hydration and lubrication of the cartilage, allowing the knee to move more smoothly and feel more comfortable.

“Hyaluronic acid injections are a good option to try to achieve improved control of symptoms, especially if you’re not seeing improvement from steroid injections,” Dr. Lippman says.

Studies have shown some individuals respond very well to hyaluronic acid treatment, while others may experience limited benefits.

“Certainly, the degree of osteoarthritis in somebody’s knee joint affects their response; more severe cases are going to be less responsive to any of these injectable therapies,” he adds.

When it’s useful and beneficial for someone, hyaluronic acid injections may be repeated every six months.

These injections are often covered by insurance, but they typically require prior authorization.

3. Platelet-rich plasma injections

Platelet-rich plasma (PRP) treatment is a regenerative therapy. Platelets are tiny cell fragments that help the body respond to injury and promote cell growth and healing. They can also help reduce inflammation in the joint space.

PRP injections involve drawing a person’s blood, concentrating platelets suspended in the blood, and then injecting that platelet-rich portion into the joint.

Although this treatment may require more time before symptoms improve compared to other injectable therapies, it provides the longest-lasting pain relief.

“Studies have shown PRP is actually the optimal injectable treatment in managing long-term arthritic pain,” Dr. Lippman says.

PRP injections can be repeated, but the frequency depends on how you respond.

At MultiCare, PRP is currently an out-of-pocket (cash-pay) procedure, which is the case across most health care systems.

When knee injections may not help with pain

Injections don’t fix structural injuries. If symptoms are from a meniscus tear, ligament injury, fracture or other mechanical problem, injections won’t address the root cause.

Advanced or severe osteoarthritis is generally less responsive to injections. Sometimes surgery is the right next step. If pain continues to limit movement and interfere with your quality of life, despite non-surgical treatments, it may be time to discuss surgical options with your provider.

“We really try to have everyone step through the process of trying injectable therapies as a middle treatment first,” Dr. Lippman says. “But if their arthritis reaches a certain point where oral medications, physical therapy or injectable therapies are not giving them enough relief, they may end up ultimately having to consider a knee replacement to surgically create a new joint surface.”

Bottom line: Talk with your provider

There’s a range of nonsurgical injection options for prolonged knee osteoarthritis pain. The best choice depends on your symptoms, severity, goals and insurance coverage. Your orthopedic provider can help match the option to your situation and adjust the plan if an injection isn’t providing meaningful benefit.

“Your provider is a great resource to help guide you and discuss which of these injectable therapies makes sense for you,” Dr. Lippman adds.