An overview of knee arthritis

Whether walking or running, sitting or standing, your knees are in use countless times every day. Unfortunately, it is all too common to experience knee problems. These can range from stiffness and mild discomfort to sharp twinges or persistent, excruciating pain.

A common cause of knee problems is a certain type of arthritis known as osteoarthritis. This hub explains more about arthritis in the knee, including:

  • Knee anatomy,
  • What is arthritis?
  • Arthritis in the knee,
  • Symptoms of knee arthritis,
  • Causes of knee arthritis,
  • Meeting your doctor,
  • Diagnostic tests,
  • Non-surgical treatments for knee arthritis,
  • Surgical treatments for knee arthritis,
  • Before your knee surgery,
  • After your knee surgery,
  • Recovering from knee surgery
  • Complications of surgery for knee arthritis,
  • Getting help for your knee arthritis,
  • Circle Health and your knee arthritis.

Are you struggling with knee problems?

If you are experiencing pain or stiffness in your knee, you don’t need to wait months to see a specialist for expert advice. At Circle, we have no waiting lists. To arrange a consultation with one of our experienced knee doctors at a convenient time for you, please contact your nearest Circle hospital.


Find out more about knee surgery at Circle Health

Knee unit at Circle Bath Hospital Knee surgery at Circle Reading Hospital


Knee anatomy

The knee is one of the largest and most complex joints in your body, formed where your thigh bone (femur) meets your shin bone (tibia). The tibia also connects with the smaller bone in your lower leg (fibula). The kneecap (patella) is a triangular bone located in front of the femur.

Commonly described as a ‘hinge joint’ due to its ability to bend, the knee also has about 30 degrees of rotational movement. Two crescent-shaped pieces of cartilage (known as the medial meniscus and lateral meniscus) are located between the femur and tibia. These menisci act as shock absorbers within the joint.

The ends of your bones are coated with a smooth, white tissue known as articular cartilage. This cartilage helps the bones of ​the knee joint to move over one another freely, with minimal friction.

What is arthritis?

Arthritis is a condition affecting the joints of the body. It can occur in people of all ages, including children. There are a couple of different types of arthritis that can affect the knee, including:

  • Osteoarthritis: This is the most common type of arthritis in the UK, causing degenerative changes in the articular cartilage of a bone. Osteoarthritis is described in more detail in the next section.
  • Rheumatoid arthritis: Caused by the immune system attacking the joints, leading to swelling, damage and sometime a change in the shape of the joint itself.

While there is currently no known cure for arthritis, your Circle doctor will give you expert advice on the very best treatments currently available to help reduce your symptoms and manage any pain you may be experiencing.

Osteoarthritis in the knee

In a healthy joint the articular cartilage covering the ends of the bones is smooth. Osteoarthritis causes the cartilage to thin, leading to friction in the joint when the bones move over one another. As arthritis develops, this thinning of the articular cartilage can become so severe that the bones of the joint end up moving directly against one other, with no protective layer between them. When this happens, the pain in the knee can be debilitating.  

The body is usually very good at trying to repair damage, but osteoarthritis causes cartilage to wear down at a faster rate than the body is able to repair it. Sometimes the healing process itself can lead to the formation of new bony growths in the joint. Called ‘osteophytes’, these hard lumps of bone lead to additional stiffness and pain, further reducing the degree of pain-free movement in the knee.  

Symptoms of knee arthritis

The exact symptoms you experience will vary depending on the type of arthritis you have and how advanced it is. While the symptoms listed below are intended for guidance, if you have any of these symptoms you should consult with a specialist knee doctor for an accurate diagnosis.

  • Pain: Most people first become aware of a problem in their knee when they have pain in it. While knee pain is a fairly common occurrence, you may start to notice that you only get pain in your knee when you move your leg in a certain way or at the end of an active day where you’ve been standing or moving a lot. Arthritic pain is often generalised over the knee rather than a pinprick, localised pain. It can also be worse in the morning or last thing in the evening.
  • Reduced movement: You may start to find certain movements, such as sitting down or standing up, more difficult. While this may not be a problem at first, as the arthritis develops further in the knee joint it can often start to limit and reduce your movements more.
  • Stiffness: You may feel increased stiffness in your knee when moving your leg. This can have the effect of making your movements feel much slower or harder than usual.
  • Weakness: You might notice that your knee has lost some of its strength. The muscles around your knee may look thinner than usual, and you might feel your knee joint giving way occasionally.
  • Swelling: You may have swelling in your knee joint as a result of inflammatory changes within the joint. This is known as synovitis and will often settle naturally over time. On occasions, this fluid may cause swelling at the back of the knee which is known as a ‘Bakers cyst’. This is not serious and will often resolve as the joint swelling settles. If it becomes painful, you should see a doctor for advice.
  • Grinding: Known as ‘crepitus’, this is a grinding, creaking or cracking felt or heard within the knee joint when it is moved.

It is important to note that these symptoms are not exclusively caused by arthritis and other illnesses, injuries and diseases can cause similar problems. However, these symptoms can often be a good indicator that something is not quite right with your knee, and it would be sensible to have it checked by a doctor to determine the cause.   

Causes of knee arthritis

Although the specific causes of osteoarthritis remain unclear, there are a number of factors known to increase the risk of developing it in the knee joint. These include:

  • Previous injury to the knee joint: A previous injury to, or operation on, the knee joint can increase the chances of developing arthritis in it at a later date.
  • Age: While arthritis in the knee can develop at any age, it is most commonly seen in people over the ages of 45-50.
  • Gender: Women are more likely to develop osteoarthritis than men. It often occurs after the menopause, for reasons that are not yet fully understood.
  • Weight: Obesity carries with it a multitude of health issues and risks, including a raised risk of developing osteoarthritis. Greater weight means an increased load and pressure is placed on the weight-bearing knee joints
  • Family history (genetics): You may be at an increased risk of developing arthritis if there is a history of it in your family.
  • Poor lower limb alignment (biomechanics): This can lead to increased wear and tear in a particular part of the knee, aggravating or exaggerating the effects of arthritis.

National and international research continues to learn more about arthritis and its causes. All our specialist knee doctors continue to keep abreast of current research, understanding and treatments for arthritis, and many of them are closely involved in ongoing research; for example, a number of Circle consultant, including Mr Ed Tayton, a consultant orthopaedic surgeon at Circle Reading, are involved in a clinical trial with the University of Reading that is investigating .

When should I see a doctor?

While many of us may accept a degree of stiffness and mild pain in the knee as a natural result of growing older, long-term and/or worsening knee problems should not be ignored. You do not have to ‘suffer silently’ with knee pain, as good medical help is available.  

In the early stages of arthritis in the knee, you may not feel the need to see a doctor. Some people worry that they will be “wasting a doctors time” when they don’t have any significant symptoms. However, it is always sensible to seek expert medical advice when you start to lose the ability to carry out certain tasks, or when the pain in your knee reaches a certain level.

If your knee pain is impairing your normal daily activities or is waking you up at night, a consultation with a specialist knee doctor is recommended.

Diagnosis of knee arthritis

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