Patients stop walking because it hurts, and because somewhere along the line they were told that walking wears the joint out. The second half of that is largely wrong, and acting on it causes real harm.

What the evidence actually shows

Moderate walking does not accelerate the structural progression of knee osteoarthritis. Several long term cohort studies point the other way: regular walkers report less frequent pain and, in some analyses, less radiographic progression than non walkers. Cartilage responds to cyclical loading. Unloaded cartilage does not stay healthy.

What walking does do is provoke pain in a knee that is already irritated. Pain during activity and damage from activity are not the same thing, and conflating them is the central mistake.

Why stopping backfires

The quadriceps weakens within weeks. A weak quadriceps transmits more load through the joint rather than less, so the knee becomes more painful, which justifies more rest. Weight tends to rise. Sleep and mood worsen. Within a year the knee is worse and the person is less able to tolerate either rehabilitation or surgery.

This cycle is one of the more common reasons a knee deteriorates faster than the X-ray predicts.

How to walk with an arthritic knee

Flat ground rather than slopes and stairs. Cushioned shoes that are actually replaced when they flatten. Shorter walks more often rather than one long walk. A stick in the opposite hand if you limp, which reduces load through the affected knee substantially and is not a sign of defeat.

Use the next morning as your gauge. Soreness during the walk that has settled by morning is acceptable. A knee that is swollen and stiff the following day means the dose was too high. Reduce distance, not frequency.

When walking is the wrong advice

A knee that is locking, giving way, or acutely swollen needs assessment before any walking programme. So does sudden severe pain after a twist. Those are mechanical problems, not arthritis to be walked through.

More here: https://www.mayurajcc.com/knee-arthritis-guides/walking-with-knee-arthritis and https://www.mayurajcc.com/knee-pain-guides/knee-pain-while-walking and https://www.mayurajcc.com/non-surgical-knee-guides/what-to-avoid-in-knee-arthritis