Knee pain

Sudden pain in the knee is usually the result of either overusing the knee or injuring it. The knee joint is particularly vulnerable to damage because it is a weightbearing joint. This means that if you are overweight you are more likely to damage your knee.

There are lots of different causes of knee pain, and the treatments for each condition are sometimes quite different. Patients with knee pain need careful examination. Dr Allfree has had extensive experience in the diagnosis and management of patients with knee pain, and he will be able to advise you on the most appropriate course of action, to help you on the road to recovery.

Common causes of knee pain

1) Simple strain

If  your pain is simply the result of having done more activity than you're used to, you've probably just strained the knee. This means that the knee tissues have stretched, but are not permanently damaged, and will recover.

You can prevent future knee pain by:

• always warming up before exercising
• increasing your activity levels slowly over time
• making sure that you replace your sports shoes before they wear out

You can also try alternative, low-impact exercises, such as swimming, to improve your fitness without doing any damage to your knee joint.

2) Anterior knee pain syndrome

Knee pain felt at the front of the knee, around the kneecap, is called anterior knee pain syndrome. The cause of this is not always clear, but it is usually aggravated by sitting for prolonged periods or by climbing stairs.

Anterior knee pain can be very difficult to get rid of, and expert help is often needed. You may need a specific regime of strengthening exercises for the muscles in front of your thigh, which Dr Allfree will be able to help you with.

3) Damage to the menisci or cartilage

Sandwiched in between the bones of the knee joint are tough pads of tissue called menisci. These cushion the bones, and act as shock absorbers. The menisci can become worn as you get older, and are commonly the reason for knee pain in middle-aged people.

A meniscus can also be torn after suddenly twisting the knee joint, resulting in pain, swelling and locking of the knee. 

These symptoms do not always settle down without treatment. Exercises can help, as can steroid injections into the joint. Sometimes an operation is needed to repair or to trim the torn pad of tissue, and if this is the case Dr Allfree will be able to help you with a referral to a knee surgeon.

4) Osteoarthritis

In older people, repeated attacks of knee pain are likely to be due to osteoarthritis, the most common type of arthritis in the UK. Osteoarthritis causes damage to the cartilage lining of the joint surfaces, and swelling of the tissues in and around the joints.

In combination with osteoarthritis in the knee, a painful fluid-filled swelling may develop at the back of the knee. This is known as a Baker's cyst. Baker’s cysts do not need specific treatment - the treatment should be directed to the underlying osteoarthritis.

Osteoarthritis can sometimes affect younger people, especially those who are overweight or who have had injuries to the knee in the past. There are various treatment options for knee osteoarthritis which Dr Allfree will be able to offer you, including steroid injections, exercise regimes and Hyalgan injections. In severe cases, joint replacement may be the only solution.

Less common causes of knee pain

1) Tendinitis

Overusing or injuring the tendon that connects the kneecap to the shin can cause patellar tendinitis (inflammation of the tendon). This condition is sometimes called "jumper's knee", because it is commonly caused by jumping activities such as basketball or volleyball.

2) Housemaid’s knee

Repetitive movement of the knee or kneeling for long periods can cause a build-up of fluid over the knee joint, known as bursitis or "housemaid's knee”. Housemaid's knee tends to affect people with certain jobs that involve kneeling (such as miners), or sports players (such as footballers). 

3) Torn ligament or tendon

Knee pain may be caused by torn ligaments or tendons. Ligaments are tough bands of tissue that connect the bones at the knee joint together, whereas tendons connect the muscles to the bone. These tissues can be torn during running sports.

If your knee is unstable or keeps "giving way", this may be due to a torn anterior cruciate ligament (one of the main knee ligaments). This is a significant injury, often caused by a sudden change in direction or a twisting movement, and is often associated with a noticeable snap at the time of injury. You may need a referral to an orthopaedic specialist for advice and treatment, although not all injuries to the anterior cruciate ligament need surgery. Sometimes an intensive regime of strengthening exercises can be enough to stabilise the knee.

4) Bleeding into the joint

An injury that causes significant damage to the knee joint may cause bleeding into the joint spaces, known as haemarthrosis. This can happen if a cruciate ligament is torn, if there is osteoarthritis in the knee, or if there is a fracture to one of the bones of the knee.

Signs of haemarthrosis are swelling of the knee, warmth, stiffness and bruising. If you have significant swelling in the joint, Dr Allfree may need to drain the knee - this is called an aspiration.

5) Osgood-Schlatter’s disease

Swelling and tenderness over the bony bump just below the kneecap is known as Osgood-Schlatter's disease. This is a common cause of knee pain in teenagers, particularly teenage boys who sprain or overuse their thigh muscles when playing sports. Mild cases usually settle with rest and taking anti-inflammatory medication. Severe cases may need referral to a specialist.

6) Gout and pseudogout

If the knee joint is hot and red, the cause is likely to be gout or pseudogout, which are both types of arthritis. Gout is caused by a build-up of uric acid in the body. Uric acid is a waste product that is produced during the process of metabolism . Usually, uric acid is excreted by the kidneys, but people whose kidneys do not excrete uric acid properly, or those who produce too much, can have high levels of uric acid in their blood. If the level becomes very high, crystals form in the joints. The crystals cause the joints to become inflamed and painful. Gout causes severe pain in the knee - often described by people as the worst pain they have ever had. Usually, gout affects the joint of the big toe first, before it affects the knee joint or any other joint.

Pseudogout is a similar condition to gout in that crystals of calcium are deposited in and around the joint. Unlike gout, pseudogout often affects the knee joint first.

7) Septic arthritis (infected knee)

Septic arthritis is a serious condition that causes a very painful, hot, swollen knee. You may also have a fever, feel unwell, and any movement of the knee will be extremely painful.

Septic arthritis can be mistaken for gout or pseudogout. You will need urgent medical attention in hopsital.

Septic arthritis is treated with antibiotics and surgery may be needed to clean out the infection.