Knee injections vs. knee replacement surgery: which is best?

Mr Rohit Jain, a leading London and Kent orthopaedic hip and knee surgeon, shares his professional medical knowledge to guide you through making a confident and well-informed decision on how to approach your knee joint treatment.

What is knee osteoarthritis?

Knee osteoarthritis occurs when cartilage, a shock absorber and frictionless surface found in all moving joints, breaks down. This breakdown causes the underlying bone to harden, form new bone and cysts within the joint, leading to pain, swelling and crunching noises during movement. Eventually, this progresses to full-grown osteoarthritis (OA).

How is osteoarthritis treated?

Managing knee osteoarthritis involves activity modification, physiotherapy, braces, maintaining a healthy weight and painkillers. When these treatments become ineffective, two main options exist: knee injection therapy and knee replacement therapy.

Treatment choice depends on the severity of pain, swelling and movement limitations, as well as the extent of bone and joint destruction caused by OA.

What is knee injection therapy?

Knee injections are categorised into two groups: pain-relieving and orthobiologic.

Pain-relieving injections, such as steroid and hyaluronic acid, involve injecting chemicals into the knee. Orthobiologic injections, like nStride and PRP, harness the body’s healing abilities.

Steroid injections, a common treatment for knee OA for decades, combine local anaesthetic with a steroid. Steroids are anti-inflammatory and reduce knee joint inflammation, pain and swelling. Effects typically last six weeks to three months, sometimes up to six months.

Hyaluronic acid injections provide similar pain relief. Hyaluronic acid, a naturally occurring substance in joint fluid, deteriorates as joints age. Injecting hyaluronic acid introduces this substance, acting as a lubricant and potentially improving existing cartilage nutrition.

PRP injections utilise the body’s healing ability. Blood contains platelets, mainly responsible for healing. In this procedure, blood is drawn from the patient and split in a machine. Platelet-rich plasma (PRP) is then separated and injected into the joint, creating a healing environment that reduces pain and maintains cartilage health.

nStride® is an advanced PRP injection with a refined structure and a more activated form of PRP. It contains beneficial proteins that restore knee joint balance and have the potential to heal cartilage, maintaining its health for almost two years.

Arthrosamid® is a cutting-edge injectable hydrogel offering long-lasting, proven pain relief for knee osteoarthritis. It improves quality of life without surgery, administered via a simple one-step procedure under local anaesthesia, allowing patients to leave the clinic the same day.

Knee replacement therapy, also known as knee arthroplasty, is primarily a resurfacing procedure. Think of it like resurfacing a broken and uneven patch of road.

Essentially, we map out the uneven knee and then lay a new surface on it. We remove worn-out cartilage and realign the joint with metal caps. Between these caps, we place high-grade plastic, creating layers of metal, plastic, and metal again. By removing the arthritic parts of the knee, pain is alleviated.

What are the risks of treatment methods?

Injection therapy is less invasive than knee replacement surgery, a major operation.

Injection risks

Side effects are minimal. There’s a small risk of infection and bleeding, comparable to a blood test. The infection risk is only 1 in 1000.

With all injections, there’s a risk of residual or recurrent symptoms because they manage the problem, not fix it. The injections help preserve the joint as long as possible.

Steroid injection

• Can interfere with blood sugar levels in diabetic patients.
• Close-to-skin injections can cause pigmentation loss, but this is rare after joint injections due to the depth of joints under the skin.

Hyaluronic injection

• Some patients experience an allergic reaction (about 1 in 100), but modern hyaluronic injections reduce this risk.

N-Stride and PRP

• These injections have the same risks as steroid and hyaluronic injections regarding pain, infection and bleeding. The advantage of these injections is they're made from your own body.

Arthrosamid

Arthrosamid injections are generally well-tolerated with the most common mild short-term side effects being injection site pain, stiffness, swelling redness or bruising. Serious risks are rare but can include post-injection pain flare-ups allergic reactions and joint infection.

Joint replacement therapy risks

Joint replacement surgery alleviates OA pain by replacing the damaged knee joint. However, as a major surgery, it carries risks:

• Pain
• Bleeding
• Infection
• Nerve and vessel damage
• Blood clots in a leg or lung

A knee joint can take up to 12-18 months to regain strength and function. Approximately 15 per cent of patients experience pain even after 18 months post-surgery. The patient’s soft tissues, including muscles, must adapt and strengthen to the new parts.

Who is suitable for either option?

The suitability of an injection or knee replacement depends on each patient’s symptoms and the stage of OA. We consider pain, swelling, loss of function and the degree of bone loss deformity in the joint. We evaluate symptom severity, joint appearance on x-rays and the patient’s age. These factors are combined to create a personalised treatment plan.

Injections are more suitable for:

• Young people;
• Those wanting to preserve their knee;
• Individuals with mild or moderate OA.

Joints with significant deformity and bone loss generally aren’t suitable for injections. In these cases, we typically recommend a knee replacement.

It’s important to remember this is a general guideline. For the best tailored treatment, consult a knee specialist. They can discuss various options suitable for you.

In your opinion, which knee osteoarthritis treatment is best?

Personally, treatment depends on the extent of OA. Most surgeons, including myself, aim to preserve the joint as much as possible. We exhaust all joint preservation techniques before considering replacement.

Given younger people’s higher activity levels, we see more patients seeking knee preservation. Knee replacement patients are often in their 60s and older. Interestingly, recent evidence shows 82 per cent of total knee replacements still function at 25 years.

Get in contact with Mr Jain to begin treating your hip and knee conditions. Begin your journey with him by visiting his profile.