Knee Osteoarthritis

Knee osteoarthritis is the gradual breakdown of the smooth cartilage that lines the knee joint, together with changes in the bone and the soft tissues around it. It is the most common form of arthritis in the knee. This page explains how it develops, how it is diagnosed and how it is treated, including treatment in turkey.

What is knee osteoarthritis?

Cartilage is the slippery, rubbery layer that covers the ends of the thigh bone, shin bone and the back of the kneecap. In knee osteoarthritis this layer becomes thinner and rougher. The bone underneath thickens, small bony spurs (osteophytes) form at the edges, and the joint lining (synovium) can swell and produce extra fluid.

Doctors once called this "wear and tear", but that label is incomplete. The joint is alive and constantly trying to repair itself. Osteoarthritis appears when damage outpaces repair, so the whole joint is involved: cartilage, bone, ligaments, muscles and lining.

Who is affected by knee osteoarthritis?

The knee is one of the joints most often affected by osteoarthritis, and it becomes more common with age, with symptoms typically starting after about 40 years of age. It is seen more often in women than in men, particularly after the menopause. People who carry extra body weight, who have had a past knee injury, or who have a family history are more likely to develop it.

It is not only a problem of older age. Younger adults can develop knee osteoarthritis after a ligament or meniscus injury, a fracture, or years of heavy knee loading.

How serious is knee osteoarthritis?

Knee osteoarthritis is usually slow and rarely dangerous to general health. Many people live for years with mild symptoms that come and go. Its main impact is on movement: walking, stairs, sleep, work and social life. For some, pain and stiffness progress to the point where daily tasks become hard.

Because it is a long-term condition, the goal is control rather than cure. Good care can reduce pain, keep you moving and delay or avoid surgery.

How this page is organised

The sections below cover anatomy, symptoms, causes and stages, then diagnosis, look-alike conditions, non-surgical care and self-care. After that we describe surgical options, when to consider them, and how treatment abroad works. We finish with complications, prevention, outlook and answers to common questions. You can read the knee overview for wider context.

The knee is a hinge-type joint where the thigh bone meets the shin bone, with the kneecap gliding in front. In knee osteoarthritis the cartilage that covers these bone ends wears down, so the joint moves less smoothly and loads are shared less evenly. Understanding the normal structure makes the symptoms easier to follow.

What is the normal structure of the knee?

The knee has three compartments. The medial compartment is on the inner side, the lateral compartment is on the outer side, and the patellofemoral compartment sits between the kneecap and the thigh bone. Each is lined with smooth articular cartilage that lets the bones glide with very little friction.

Two C-shaped pads of cartilage, the menisci, sit between the thigh bone and shin bone. They absorb shock and spread load. Four main ligaments (the ACL, PCL, MCL and LCL) steady the joint, and the quadriceps and hamstring muscles control it.

A thin joint lining called the synovium makes lubricating fluid. This fluid feeds the cartilage, which has no blood supply of its own and relies on movement to receive nutrients.

What changes in knee osteoarthritis?

The first change is usually softening and fraying of the cartilage surface, often called worn knee cartilage. As it thins, small cracks deepen, and in advanced disease the bone underneath can be exposed. Exposed bone becomes dense and polished (sclerosis), and cysts may form just below the surface.

The body responds by growing bony spurs at the joint margins. These can make the knee look larger and feel stiffer. The synovium becomes inflamed, causing swelling, warmth and an effusion (extra fluid) after activity.

The menisci often fray and may tear. Nearby muscles weaken because pain makes you use the leg less, which reduces the support the joint receives and can speed the process further.

In many people the inner compartment wears first, which can pull the leg into a bow-legged shape (varus). Less often the outer side wears and the leg drifts knock-kneed (valgus). This pattern matters later, because it guides the choice between partial replacement, osteotomy and total replacement.

Why does cartilage not simply heal?

Healthy cartilage contains few cells and no direct blood supply, so it repairs slowly and incompletely. Once the surface is badly worn, the body cannot regrow it to its original quality. That is why current treatment focuses on easing symptoms, protecting the joint and improving function.

Doctors describe knee osteoarthritis by its cause, by the compartment involved and by how advanced it looks on X-ray. These labels are not just academic. They help decide whether exercise alone is enough, whether a partial replacement is possible, or whether the whole joint needs resurfacing.

What are the main types of knee osteoarthritis?

Primary osteoarthritis has no single clear trigger. It develops gradually with age, genes, weight and general joint use. Secondary osteoarthritis follows a known cause such as an old fracture, ligament injury, meniscus loss, infection or inflammatory disease. Secondary forms often appear earlier in life and may be limited to one knee.

By location, doctors speak of medial, lateral and patellofemoral disease. When only one compartment is worn and the ligaments are sound, the problem is called unicompartmental. When two or three compartments are involved, it is described as tricompartmental.

How are the stages of knee osteoarthritis graded?

Knee osteoarthritis stages describe how far the damage has advanced, from a normal joint to severe loss of cartilage.

The most widely used system is the Kellgren and Lawrence scale, which grades X-ray changes from zero to four. Grade zero is a normal knee, and grade four is severe disease. It is a guide, not a verdict, because pain and function do not always match the picture on the film.

Why does staging change the treatment plan?

Early stages respond well to exercise and weight control, and surgery adds little. Middle stages may suit injections, bracing or, in selected people, an osteotomy. Late stages with constant pain, stiffness and deformity are where a knee replacement most often gives the clearest benefit.

Your symptoms still matter more than the grade. Someone with grade three changes who walks comfortably may need no operation, while another person with similar films may struggle to sleep.

Knee osteoarthritis is mainly diagnosed from your story and a physical examination, then confirmed with a weight-bearing X-ray. Most people do not need an MRI scan to be diagnosed. Tests are used to confirm the pattern, rule out other problems and plan treatment if surgery is being considered.

How is knee osteoarthritis diagnosed?

Your doctor will ask where the pain is, when it comes on, how long morning stiffness lasts, and what it stops you doing. They will ask about earlier injuries, family history, work and sport, and any medicines you take. A typical pattern in a person over 45 is often enough for a confident clinical diagnosis.

The examination looks at how you walk, the shape of your legs, and whether the knee is swollen. The doctor checks the range of movement, feels for tenderness along the joint line, listens for crepitus, and tests the ligaments for stability.

Which imaging is used and why?

A standing (weight-bearing) X-ray is the first-line test. Standing matters because the gap between the bones narrows under body weight, so lying-down films can underestimate the damage. Views from the front, side and a skyline view of the kneecap give a complete picture.

An MRI scan shows cartilage, menisci and ligaments in detail. It is not routinely needed, but it can help when the story suggests a meniscus tear, bone bruising, a stress fracture or avascular necrosis. Ultrasound can show fluid and tendon problems. A full-length leg X-ray measures alignment before an osteotomy or robotic replacement.

What blood and fluid tests may be used?

There is no blood test for osteoarthritis itself. Blood tests are used to look for other causes of joint pain, such as rheumatoid arthritis or gout. If the knee is hot, red and swollen, fluid may be drawn with a needle and examined for crystals or infection.

What should you bring to a remote review?

If you plan to ask a turkish surgeon to review your case from home, gather the right records first. A clear file saves time and avoids repeat tests. Our medical record review guide explains the process step by step.

• Recent standing X-ray images in digital format (not only the written report).
• Any MRI scan files and the radiologist report.
• A list of past injuries, injections, arthroscopies or operations on either leg.
• Your current medicines, allergies and other medical conditions.
• Your height, weight and a short description of what you can and cannot do.

Non-surgical care is the first treatment for almost everyone with knee osteoarthritis, and it can control symptoms for years. The core of it is exercise, weight management and education, with medicines and injections as add-ons. Guidelines from bodies such as NICE put these ahead of any operation.

Why is exercise the foundation of treatment?

Studies consistently show that strengthening and aerobic exercise reduce knee pain and improve function in knee osteoarthritis. The effect is similar in size to some medicines, without the side effects. Strong thigh muscles absorb shock, steady the joint and reduce the load on worn cartilage.

A physiotherapist usually designs a programme with leg strengthening, balance work and gentle aerobic activity such as cycling, swimming or walking. Benefits tend to appear within 6 to 12 weeks, but they fade if exercise stops. Sessions of 20 to 30 minutes, 3 times a week, are a realistic target. Think of it as long-term maintenance.

How does weight loss help?

For people with extra weight, losing some of it eases the load on the knee. Every step carries a force several times your body weight, so even modest weight loss can reduce pain. Studies suggest that losing around 5 to 10 percent of body weight gives noticeable benefit when combined with exercise.

Which medicines are used?

Doctors begin with the safest options, and review the plan after about 2 to 4 weeks. Topical anti-inflammatory gels or creams applied to the knee are often recommended first, because little reaches the rest of the body. Oral anti-inflammatory tablets (NSAIDs) work better for many people but carry stomach, kidney and heart risks, so the lowest effective amount for the shortest time is used.

Paracetamol is widely used but studies suggest it helps osteoarthritis pain only a little. Some people use duloxetine or short courses of weak opioids when other options fail, though these have significant side effects. Your doctor will tailor the choice to your other health conditions. Never combine medicines without advice.

What about injections?

A corticosteroid injection into the knee can calm a flare of pain and swelling, with relief that often lasts 4 to 12 weeks. Repeated injections are usually limited because of concerns about cartilage and tissue effects. They are also best timed with care ahead of any planned surgery.

Hyaluronic acid injections and platelet-rich plasma (PRP) are widely offered, but the evidence is mixed. Some people report benefit, while major guidelines are cautious. A good clinic will explain this honestly and will not promise that an injection will rebuild cartilage.

Do braces, insoles and walking aids help?

An unloader brace can shift weight away from a worn inner compartment in selected people with bow-legged alignment. Supportive shoes, a walking stick held in the opposite hand, and activity pacing all reduce stress on the joint. Heat and cold packs give short-term comfort.

How long should you try non-surgical care?

Most doctors suggest a committed trial of at least 3 months with supervised exercise, weight advice and suitable medicines before surgery is discussed. If your pain still limits sleep, work or walking despite this, the question of surgery becomes reasonable. We cover that decision in the section on when to consider surgery below.

When non-surgical care no longer controls knee osteoarthritis, five operations are commonly discussed: knee arthroscopy, osteotomy, partial knee replacement, total knee replacement and robotic-assisted replacement. Each suits a different person and a different pattern of damage. The right choice depends on age, activity, alignment, which compartments are worn and your overall health.

When is knee arthroscopy useful?

Knee arthroscopy is keyhole surgery in which a small camera and instruments are used inside the joint. Large trials show that washing out or trimming a generally worn knee does not help most people with osteoarthritis. It may still help in selected cases, such as a clearly locking meniscus fragment or a loose body. You can read about knee arthroscopy in turkey here.

What does a knee osteotomy do?

Knee osteotomy cuts and reshapes the shin or thigh bone to move load away from the worn compartment. It suits younger, active people with wear confined to one side and a clear bow-leg or knock-knee alignment. It keeps your own joint, but recovery is longer, because the bone must heal over about 6 to 12 weeks. See knee osteotomy in turkey for the local pathway.

Who suits a partial knee replacement?

Partial knee replacement resurfaces only the worn compartment and keeps the healthy parts and ligaments. It suits people whose arthritis is limited to one compartment with stable ligaments and a good range of movement. Recovery is often quicker and the knee often feels more natural, though revision rates can be higher than for total replacement. Details for partial knee replacement in turkey are on its own page.

When is a total knee replacement recommended?

Total knee replacement removes the worn surfaces of the thigh bone, shin bone and often the kneecap, and replaces them with metal and plastic implants. It is the standard operation for advanced knee osteoarthritis with pain, stiffness and loss of function. Most people report a major reduction in pain, and implants commonly last many years. Read total knee replacement in turkey for the pathway.

What is robotic knee replacement?

Robotic knee replacement uses a planned, computer-guided system to help the surgeon place implants and balance the joint. It is a tool for precision rather than a different type of implant. Studies suggest more accurate positioning, but long-term differences in how people feel are still being studied. See robotic knee replacement in turkey.

How do the options compare?

For realistic planning, see the cost guides for total knee replacement, partial knee replacement, robotic knee replacement, knee arthroscopy and knee osteotomy. Our wider joint replacement service page also helps.

You cannot completely prevent knee osteoarthritis, but you can lower your risk and slow its progress. The most effective steps are staying at a healthy weight, keeping the thigh muscles strong, avoiding knee injuries and treating them properly when they occur. Some risk factors, such as age, sex and genes, cannot be changed.

Which steps reduce your risk?

• Maintain a healthy body weight; this is one of the strongest modifiable factors.
• Keep active with a mix of strengthening, balance and low-impact aerobic exercise.
• Warm up before sport, use sensible footwear and build training gradually.
• Seek early assessment for knee injuries such as ligament or meniscus tears.
• Use protective kneeling pads or take breaks if your work involves long kneeling.

How can you slow progression if you already have it?

Continue your exercise programme, keep your weight steady and pace activities. Treat related problems promptly, such as patellofemoral pain or ligament injuries like an ACL tear. Injuries that damage the joint surface may lead to post-traumatic knee arthritis, so proper rehabilitation is worth the effort.

Does diet or supplement use matter?

No special diet prevents the condition, but a balanced pattern rich in vegetables, fish, pulses and whole grains helps weight control and general health. Supplements such as glucosamine and chondroitin have shown little consistent benefit in large studies. Discuss any supplement with your doctor first, especially if you take blood thinners.

What cannot be prevented?

Ageing, family history and some alignment problems are beyond your control. Having these risk factors does not mean you will develop severe disease. Many people with a family history stay comfortable for life, and good habits still make a difference.

The outlook for knee osteoarthritis is generally good for managing symptoms, though the joint itself does not return to normal. Many people remain stable for years, while others slowly worsen. The speed of change varies, and daily function usually matters more than the appearance of the X-ray.

What is the natural course of knee osteoarthritis?

Symptoms often come in flares with quieter spells in between. Some people have a slow, steady decline, while others remain mild for a long time. Staying active, keeping your weight under control and building muscle strength all improve the odds of a good long-term result.

What can you expect after non-surgical treatment?

Most people notice improved pain and function within 2 to 3 months, and a trial of 3 to 6 months is typical of regular exercise and weight management. The gains hold only while you keep going. Flares are normal and do not mean the exercise is harming the joint. A review with your doctor each year helps adjust the plan.

What can you expect after knee surgery?

After total knee replacement, most people walk with support on the day of or day after surgery. Many use a stick for 2 to 4 weeks and return to desk work within about 6 weeks, with heavier work taking longer. Improvement continues for up to 12 months, and swelling can persist for months.

Partial replacement often allows a somewhat quicker return to activity. Osteotomy usually needs a longer period of protected walking while the bone heals. Low-impact activities such as swimming, cycling, golf and walking are usually encouraged; high-impact sports are generally discouraged.

How long do results last?

Modern knee replacements often last 15 to 20 years or more in most people, though results vary with age, weight, activity and implant type. Younger and heavier patients may face revision sooner. If an implant wears or loosens, a revision knee replacement can be performed.