Knee Replacement in the UK: Everything You Need to Know Before Deciding

Knee replacement is one of the most commonly performed surgeries in the UK — roughly 100,000 per year. The procedure has high satisfaction rates, but "high" is not "universal," and the gap between a good outcome and a mediocre one is often determined by decisions made before the operation, not during it.

The numbers that matter

Overall, around 80–85% of patients report significant improvement in pain and function after total knee replacement. That leaves 15–20% who don't. Understanding why — and whether you're at higher risk of being in that group — is the first step.

Factors that affect outcomes include: body weight, pre-operative range of motion, expectations, strength of the surrounding muscles, and the quality of post-operative rehabilitation. These are modifiable. Optimising them before surgery directly improves your chances.

Surgeon volume matters — a lot

The evidence on this is unambiguous. Surgeons who perform more than 50 knee replacements per year consistently achieve lower complication rates, lower revision rates, and higher patient satisfaction. For complex or revision cases, you want a surgeon doing significantly more than that.

In the UK, the National Joint Registry publishes revision rates by hospital and, in some cases, by surgeon. This data is publicly available and should inform your decision. Here's how to use it.

The rehabilitation question

A knee replacement without proper rehabilitation is like buying a sports car and never servicing it. The surgical technique matters, but the 12 weeks of physiotherapy afterwards determine whether you achieve an excellent result or a merely acceptable one.

Before agreeing to surgery, establish exactly what rehabilitation pathway is in place. How many physiotherapy sessions? Over what period? What are the milestones? If the NHS provision is limited — which it often is — plan for private physiotherapy in advance.

When not to have a knee replacement

Not everyone with knee arthritis needs a replacement. Physiotherapy, weight management, injections, and activity modification can provide significant relief for many patients. Surgery should be considered when conservative measures have been properly exhausted — not when they've been briefly attempted.