Knee Osteoarthritis (Gonarthrosis)

The cartilage that lets the joint surfaces glide has thinned, the bone beneath it has thickened and the joint lining is intermittently inflamed. The pain comes from the bone and the lining, not the cartilage, which is why an X-ray that looks terrible can belong to a knee that hurts little, and the reverse.

What the patient notices is stiffness after sitting, pain on stairs — coming down more than going up — swelling after a long day, and a knee that no longer straightens or bends fully. Muscle around the joint wastes quickly once the knee is used less, and that weakness then adds its own pain.

Corticosteroid injections give only short-term relief 3 and arthroscopic surgery is recommended against in nearly all worn knees 2, whereas exercise, including strengthening of the thigh muscles, has high-quality evidence for reducing pain in knee osteoarthritis, with the benefit still measurable two to six months after the programme ends 1. The programme is built on that: progressive loading of the quadriceps and hip muscles, range work, and walking retraining.

Hydrotherapy lets a painful knee begin loading in water before it tolerates the same work on land, and is where most programmes start. Laser, shockwave and radiofrequency are used for pain so that the exercise can happen, not instead of it.

Range of motion, thigh strength, walking speed, the time it takes to rise from a chair and climb a flight of stairs, and a validated knee score are recorded at the start and the end. The gait laboratory shows how the other knee and the back are compensating, which matters for the joint that is not yet painful.

Those figures are what we use to answer the question most patients arrive with: whether a replacement can wait. A knee that improves measurably on the programme can usually wait; one that does not, despite good adherence, is telling you something, and we say so.

Night pain that no longer responds, a joint that has lost most of its range, or a deformity that is progressing are the signs that the knee has passed the point where exercise can hold it. At that stage rehabilitation is planned around the operation: exercise before a replacement improves strength and function afterwards, although the effect fades and is mostly confined to the first six months 6.

Weight matters: in a trial of overweight older adults with knee osteoarthritis, each kilogram of weight lost was associated with about four kilograms less load on the knee with every step 4, and the dietitian is part of the programme where that applies.