Steroid injection vs knee replacement for osteoarthritis

Knee osteoarthritis care is stepped. At the base are exercise, strengthening, weight management where relevant and simple pain relief. Injections are a short-term aid on top of that, and surgery is considered when those measures no longer control the problem. Treating the injection and the replacement as rivals misses the point: they are tools for different stages.

Many people use an injection to get through a bad flare or a planned event, or to confirm that the knee is the pain source, before deciding about surgery.

A corticosteroid, usually with local anaesthetic, is injected into the knee joint. It reduces inflammation and often gives a few weeks of relief, sometimes longer, sometimes none. It does not repair cartilage, slow the arthritis or change the underlying joint. A short flare of pain after the injection can occur, and rare risks include infection and skin changes.

Because steroid can affect joint tissues and the risk of infection after later surgery, many surgeons ask that a replacement is not done within a few months of an injection. This is a reason to plan the sequence with your surgeon.

Total knee replacement removes the worn surfaces of the thigh bone and shin bone and replaces them with metal and plastic components, often with a surface for the kneecap. Most people achieve substantial pain relief and better function, though satisfaction is not universal and some people have persistent pain. Recovery needs weeks of structured exercise and months to reach full benefit.

Risks include infection, blood clots, stiffness and the need for revision in the longer term. The operation is major, and heart and lung health, diabetes and weight are assessed before it.

NICE NG226 recommends core treatments for everyone with osteoarthritis, including exercise, and that clinicians consider intra-articular corticosteroid injections for short-term relief of moderate to severe pain, while not offering hyaluronan injections. It recommends referral for joint replacement when joint symptoms substantially affect quality of life and non-surgical treatment has not been effective.

The surgeon will consider your X-rays, functional limitation, general health and goals, and may recommend delaying surgery if you are likely to benefit from further non-operative care or from addressing health risks such as smoking or poorly controlled diabetes first.

• Occasional flares with otherwise tolerable knees: exercise and a planned injection can help; ask your clinician for advice on timing.

• Constant pain, night pain, difficulty with stairs and walking, and impact on sleep and work despite treatment: ask for an orthopaedic opinion on replacement.

• Planning knee replacement soon: tell your surgeon about any recent injections, since timing matters.

• Unsure the knee is the source of pain: an injection can be diagnostic in some cases.

• Severe pain after a fall, a hot swollen knee with fever, or inability to bear weight: seek urgent assessment.

Injections do not rebuild cartilage, and the effect is temporary. Knee replacement is also not just for the elderly, nor something to be postponed indefinitely at the cost of quality of life. Having an injection does not "use up" your chance of surgery, though timing before surgery matters.

And "bone on bone" on an X-ray is not alone an indication for surgery; symptoms and function guide the decision.