"I have knee osteoarthritis, so do I have to stop walking?" It is the question we hear most often when a report with the word gonarthrosis arrives. And the answer, which surprises almost everyone, is the opposite: the most effective treatment we have for knee osteoarthritis is not a drug, not an injection, not rest. It is exercise, done well and consistently.
In this guide we look at what gonarthrosis really is, what the "grades" in the report mean, which exercises to do (with sets and repetitions), what to avoid and, honestly, when it makes sense to talk about injections or replacement.
Gonarthrosis: what it is and what the grades mean
Gonarthrosis is osteoarthritis of the knee: a process in which the cartilage lining the joint thins over time, the bone underneath reacts, and the joint becomes stiffer, sometimes swollen, sometimes painful. It is a process that comes with age, to the point that after the age of 60 a very large share of the population shows signs on X-ray, often without knowing it.
In reports you usually find a classification in grades, from 1 to 4:
- Grade 1-2 (mild): the joint space begins to narrow, the first osteophytes ("bone spurs") appear. Many people at this stage have few symptoms or none.
- Grade 3 (moderate): clear narrowing of the joint space; morning stiffness, and pain on stairs and when standing up from a chair, become more frequent.
- Grade 4 (severe): the joint space is almost absent. This is the stage at which, if the symptoms are severe too, surgery is considered.
The most important point, worth putting in bold: the grade on the X-ray and the pain you feel do not go hand in hand. There are grade 3 knees that cause little pain and grade 2 knees that are very painful. Pain also depends on muscle strength, weight, activity, sleep and fear of movement. And it is precisely on these factors that we can work, whatever your grade.
Exercises for gonarthrosis: why they are the first-line treatment
On this, international guidelines have agreed for years: for knee osteoarthritis, therapeutic exercise, education and weight management are the first-line treatment, ahead of drugs and well ahead of surgery. It is not an opinion of ours as physiotherapists: it is the standard of care recommended worldwide.
Why does it work, if the cartilage is worn? For three concrete reasons:
- Stronger muscles unload the joint. A trained quadriceps and glutes absorb part of the load with each step, reducing the stress on the cartilage that remains.
- Movement nourishes the joint. Cartilage has no blood vessels: it is fed by synovial fluid, which circulates precisely because of movement. A still knee is a knee that stiffens.
- Exercise recalibrates pain. Gradual, regular movement makes the system less "on alert": within 6-8 weeks most people feel less pain and climb stairs better, with the same X-ray.
And no, correct exercise does not "wear out" the knee faster. What speeds up the problems is the opposite: inactivity, loss of strength and extra kilos.
The programme: exercises with dosage
A practical rule for all the exercises: discomfort up to 4-5 out of 10, which fades quickly and does not leave the knee worse the next day, is acceptable. Pain that grows set after set, or that makes you limp the following day, means reducing the load or the repetitions, not stopping.
| Exercise | How to do it | Dosage |
|---|---|---|
| Quad set | Seated or lying, leg straight: tighten the thigh pressing the knee downwards, hold 5-10 seconds | 3×10, every day |
| Straight leg raise | Lying, one leg bent and the other straight: lift the straight leg 30 cm, hold 5 seconds, lower slowly | 3×10 per leg, 3-4 times/week |
| Sit-to-stand | Stand up from a chair and sit back down slowly, without helping yourself with your hands (use a higher chair if it is too hard) | 3×8-12, 3 times/week |
| Mini squat | Standing, holding onto a piece of furniture: bend the knees to 30-45°, weight on the heels | 3×10, 3 times/week |
| Bridge | Lying, feet on the floor: lift the pelvis by contracting the glutes, hold 3 seconds | 3×12, 3 times/week |
| Step-up | Step up onto a low step with the affected leg, control the descent | 3×8 per leg, 3 times/week |
| Heel slides | Lying, slide the heel towards the buttock and back, for flexion mobility | 2×15, every day |
| Stationary cycling | Saddle slightly high, light-to-moderate resistance | 20-30 minutes, almost every day |
| Walking | Comfortable pace, even ground, cushioned shoes | 20-30 minutes, almost every day |
How to progress: when an exercise becomes easy, do not keep adding repetitions indefinitely: increase the difficulty (a lower chair, a higher step, a small weight on the ankle, a slightly deeper squat). The real benefits arrive after 6-8 weeks of regularity: the first two weeks are only for getting going, so do not judge the programme before then.
Knee osteoarthritis: exercises to avoid (and what does not need avoiding)
To limit, especially in the painful phases:
- Sudden spikes in load: the classic Sunday with 15,000 steps after a week of 2,000. The arthritic knee dislikes spikes, not steps.
- Deep squats and lunges loaded at full depth, repeated jumps, downhill running: these are the movements most likely to switch on symptoms.
- Complete rest "while waiting for it to pass": after a few days of stopping the muscles weaken and the knee, on resuming, is worse than before.
- Chasing a lot of passive therapies (gels, mud packs, gadgets) as the main plan: some may give temporary relief, none replaces strength and movement.
What does not need avoiding: everyday stairs, walking, cycling, swimming, bending down to pick something up. A knee with gonarthrosis should be used, intelligently. Body weight deserves a word too: if there are extra kilos, every kilo lost is multiplied in the load the knee receives with each step, and what you eat can help your knees more than you might imagine.
How intense the exercises need to be
Here is a finding that takes a weight off many people. A Cochrane review compared high-intensity exercise programmes with low-intensity ones in people with hip or knee osteoarthritis, and found no relevant clinical advantage of high intensity for pain and function in the short term, with evidence of low to very low quality, and without certainty even that high intensity is riskier (PMID 26513223).
Put into practice: you do not need to suffer to get results. If a light load lets you be consistent for eight weeks, it is worth more than a hard programme you drop after ten days. It is no coincidence that the 2025 Cochrane update on this topic concerns interventions to improve adherence to the programme (PMID 40678987): the real clinical problem is not finding the perfect exercise, it is keeping on doing it.
Medication: what it does and what it does not
Medication serves to make movement possible, not to replace it.
Anti-inflammatories can lower pain in an acute phase and let you do exercises you would otherwise skip, but they are symptomatic management: they do not change the course of the osteoarthritis, and long-term use should be discussed with your doctor, because they are not without effects on the stomach, kidneys and blood pressure.
On injections: corticosteroids can give relief in very irritated phases, typically for weeks, not for ever. Hyaluronic acid has more debated evidence, and opinions across guidelines do not coincide. In both cases the right question is not "does it work?" but "what do I use this window of relief for?": if it serves to get back into an exercise programme, it makes sense; if it serves to postpone, the knee returns to the starting point.
Knee sleeves, insoles and the stick
These are aids, that is, tools that take load off while you work on the rest.
A knee sleeve can give a sense of stability and reduce pain in some people; it does not strengthen anything and should not be worn all day, every day, because the work has to be done by the muscle. Cushioning insoles may help to dampen the impact. The stick, used on the side opposite the painful knee, really does reduce the load when you walk for a long time, and it is not giving in: it is the difference between going for the walk and not going.
Injections and replacement: when it makes sense to talk about them
Let us be honest about them, because sooner or later someone will suggest them to you.
Injections (corticosteroid, hyaluronic acid) can have a role as support: corticosteroid can calm a very inflamed phase, and hyaluronic acid gives some people relief lasting a few months. But they are a symptomatic aid, not a cure: they do not rebuild cartilage, and they work best precisely when they are used to make exercise possible, not to replace it. If an injection is proposed to you without any strengthening programme alongside it, it is legitimate to ask questions.
Replacement is an excellent operation, but it is the last card, not the first: it is considered when the osteoarthritis is severe (usually grade 4), the pain concretely limits daily life and sleep, and a serious exercise programme lasting at least a few months has not been enough. Two things few people say: arriving at the operation with trained muscles clearly improves recovery afterwards; and even with a replacement, rehabilitation remains the factor that decides the result.
Living well with gonarthrosis
Gonarthrosis is a chronic condition, but "chronic" does not mean "inevitably worsening". It means it has to be managed, like high blood pressure: people who train regularly, keep their weight under control and dose their loads live for decades with knees that work well.
The programme above is an excellent starting point, but it is generic by definition: your knee has its own history, its own starting strength and its own critical movements. If you want a programme built around you, with exercises shown and corrected on a video call and progressions reviewed week by week, take a look at our pathway for knee pain or start with the questionnaire: 20 minutes with a physiotherapist to assess your situation and work out where to start, without leaving home.
If you have been offered magnetotherapy for the knee, what the studies say is in Magnetotherapy: what it is for and what the studies really say.
If you are considering supplements (collagen, glucosamine, turmeric), what the meta-analyses say is in Collagen for the joints: does it really help?.
If you have been offered an injection
It happens to almost everyone, and the right question is not whether to have it: it is what you do afterwards. The three that circulate, corticosteroid, hyaluronic acid and PRP, win in different moments, and one of them has an awkward study behind it on cartilage. The full picture, including the part that puts us physiotherapists in an uncomfortable position, is in knee injections.
Sources
- Exercise for osteoarthritis of the knee - Cochrane Database of Systematic Reviews, 2015
- EULAR recommendations for physical activity in people with inflammatory arthritis and osteoarthritis: 2025 update - Annals of the Rheumatic Diseases, 2026
- Osteoarthritis in over 16s: diagnosis and management (NICE Guideline NG226) - National Institute for Health and Care Excellence, 2022
Last check of the sources: August 2026.
