Signs you might need a knee replacement

The knee is a weight-bearing hinge — there's nowhere for it to hide. When arthritis is the driver, pain typically sits on the inside (medial) side of the knee or directly behind the kneecap, and it gets worse with stairs, slopes, and long walks.

Pain that's clearly mechanical — sharp catches, locking, the knee giving way unexpectedly — is more often a meniscus or ligament story and worth investigating separately. Arthritis pain is usually a deeper, achier, more grinding quality.

A stiff knee is a knee that has stopped tolerating its workload. Mild swelling after a busy day, difficulty fully straightening or fully bending, and a "grinding" feeling under the kneecap are all classic signs of cartilage wear.

Pay attention to range of motion in particular. A knee that can no longer fully straighten changes the mechanics of the whole leg and is harder to rehabilitate later — one reason to not wait until the joint is completely locked.

A useful self-check: how far can you comfortably walk on flat ground without stopping? If the honest answer has gone from "as far as I like" to "about a block" over a year or two, the knee is steering your life.

Stair-climbing is the more sensitive test. Difficulty going down stairs (where the joint takes 3–4× body weight) often shows up before difficulty going up.

If you've genuinely tried the conservative path — weight management where it applies, physiotherapy, anti-inflammatories if safe, occasionally a corticosteroid or hyaluronic-acid injection — and pain or function are still slipping, the joint is asking for more than tools that don't change the underlying cartilage.

The non-surgical treatments guide covers what's reasonable to try first, and how long to try it.

Not every arthritic knee needs a total replacement. When only one compartment is worn — most often the inner (medial) side — a partial knee can replace just that surface and preserve the rest of the joint. That decision is made on imaging and exam, not on preference.

We talk through the trade-offs in partial vs total knee replacement.

A reasonable threshold: when knee pain, stiffness or instability are meaningfully shrinking your activity and sleep, and a fair trial of conservative care hasn't kept up, it's time for a proper conversation. That doesn't commit you to surgery — it commits you to understanding your options.

If you want to see what the conversation looks like, read what to expect at your first consultation.