Knee pain

If you have sudden on-set joint pain this is likely due to an injury or trauma, whereas a chronic ache or dull pain may be caused by an underlying condition such as osteoarthritis or tendonitis.

The most common causes of knee pain are:

• Baker's cyst
• Disease
• Gradual wear and tear
• Injuries, such as an anterior cruciate ligament injury, dislocated knee or sprain
• Meniscus tear
• Swollen knee

If you experience knee pain when bending, walking and even resting that lasts longer than a few days, it could be a sign of joint damage. Ageing is a major cause of worn-out knee joints, often due to osteoarthritis. Other factors such as genetics, previous injury and lifestyle can play a part, so speak to your GP if you're experiencing any of these symptoms.

If you have sore knees related to osteoarthritis, you may also experience other symptoms in your knee such as:

• Creaking
• Limping
• Reduced movement
• Stiffness

Common causes of knee pain after injury

• Dislocated knee — occurs when your kneecap changes shape after a collision or sudden change in direction 
• Osgood Schlatter's disease — mainly affects teenagers and young adults, and causes pain and swelling below the kneecap
• Sprain or strain — pain after overstretching, overusing or twisting your knee eg during exercise
• Tendonitis —  pain between your kneecap and shin (front part of your leg) usually caused by repetitive jumping or running
• Torn ligament, meniscus or tendon, or cartilage damage — when the injury occurs you may hear a popping sound; symptoms include: 
• An inability to straighten your leg 
• Instability 
• Pain 
• Your knee giving way when you try to stand 

Underlying conditions that cause knee pain

• Bleeding into the knee joint — while this usually occurs after injury to the knee, it is more common in people taking anticoagulants eg warfarin
• Bursitis — inflammation of the fluid-filled sacs in your knee (bursae), which causes pain, redness, swelling and warmth; pain and swelling worsen when bending or kneeling
• Gout — a type of arthritis caused by uric acid crystals building up in your knee joint; this causes repeated attacks of pain, redness and warmth
• Osteoarthritis — this is more common in older people and causes pain, stiffness and mild swelling in both knees
• Septic arthritis — inflammation caused by a bacterial infection of your joint, which causes pain, redness and warmth to develop quickly; if you are you concerned you have septic arthritis, see your GP or visit A&E as soon as possible

Sports injury

Knee pain is a common symptom of injuries and conditions related to sports and activity. If your knee pain is the result of a sudden injury, particularly a twist or excessive stretch, then you might have a sprain or strain, or other damage to cartilage or ligaments.

Common injuries resulting from sports or activity include: 

• Anterior cruciate ligament injury — the anterior cruciate ligament (ACL) connects your thigh bone to your shin bone via your knee joint; injuries to this ligament include sprains and partial or complete tears; symptoms include considerable pain and restricted movement
• Fracture — a break or crack in any of the bones in your knee joint eg the thigh bone, kneecap or shinbone
• Knee bursitis — inflammation of the bursae in your knee
• Meniscus tear — a tear to the meniscus, a thick pad of smooth cartilage in your knee that sits between the ends of your shinbone and thigh bone
• Patellar tendonitis — inflammation of the tendon that connects your kneecap to your shinbone; also known as jumper’s knee

Overuse or repetitive movement

If your knee pain appeared gradually and you haven't experienced any obvious or sudden trauma, then you could have tendinopathy. This is often brought on by repeated running or jumping. Alternatively, you could have bursitis (also known as housemaid's knee).

If you experience pain on the outer side of your knee, you may have iliotibial band syndrome — inflammation of the outer side of your knee due to overuse eg caused by long-distance running.

Disease

Knee pain can also be caused by joint diseases and conditions unrelated to any injury. If you're aged over 50, there's a chance that knee pain is a sign of osteoarthritis. However, other types of arthritis can also cause knee pain, such as: 

• Gout or pseudogout
• Rheumatoid arthritis
• Septic arthritis

Knee pain in teenagers can be caused by Osgood-Schlatter disease, a condition often related to bone growth and overuse.

In rare cases, knee pain may be due to osteosarcoma, a type of bone cancer that most often occurs in the knee.

Other conditions

If you sustain an injury in or around your knee, you may experience knee pain due to loose bodies. These are small fragments of shattered bone or cartilage that get caught in your knee joint.

Knee pain could also be referred pain — pain you feel in one area despite the source of the pain being elsewhere eg hip or foot pain.

• Being overweight or obese
• Certain occupations and sports that put greater stress on your knees
• Having weak or inflexible muscles 
• Past knee injuries

If your knee pain is due to osteoarthritis, you may experience more joint damage, disability or knee pain in the future. 

If your knee pain is due to injury, your risk of future knee injuries is higher. 

You can reduce your risk of knee pain in different ways, including: 

• Maintaining a healthy weight — excess weight puts more strain on your knees
• Performing regular low-impact exercises to strengthen the muscles around your knees and stay flexible eg cycling or swimming
• Reducing high-impact activities eg don't run down hills, walk instead 
• Training well for sports — do not suddenly increase the intensity of your sports activity but gradually increase it through training
• Using appropriate footwear — this includes: 
• Replacing your running shoes often — this ensures they have enough cushioning and support
• Using shoe inserts if needed — these can help if you have problems with your feet or gait 
• Warming up properly before exercising and warming down properly after — stretch your hamstrings and quadriceps before and after exercise

Also, when you are out walking, avoid rough, uneven roads; try to stay on smooth, paved roads.

• You should see your GP about severe or ongoing knee pain as soon as possible, particularly if it's:

  • Affecting your overall mood and positive wellbeing
  • Affecting your sleep
  • Preventing you from getting on with your everyday life

  If you experience the following symptoms, you should also see your GP:

  • You can't bear weight on your knee or it feels like your knee will give way
  • You can't fully extend or bend your knee
  • You have a fever as well as knee pain, redness and swelling
  • You have severe knee pain after an injury
  • Your knee is obviously swollen
  • Your knee or leg looks deformed

  Your GP will carry out a physical examination of your knee. This may include: 

  • Checking for bruising, pain, swelling, tenderness and warmth
  • Checking how far you can move your lower leg in different directions
  • Gently pushing on or pulling on your knee joint to check the integrity of its structures

  They will also ask you some questions. You may therefore find it useful to think about your answers to the questions below before your appointment: 

  • When did your knee pain start and was it after an injury?
  • Are your symptoms constant or do they come and go?
  • How severe are your symptoms?
  • Does anything improve or worsen your symptoms?
  • Do you take any medications or supplements, and if so, what?
  • Do you exercise or play sports, and if so, what activities?

  They may also ask if you: 

  • Have any instability, locking of your knee or swelling
  • Have had knee pain before and if so, what the cause was
  • Have symptoms in other areas

  Your GP may refer you for: 

  • An X-ray — this is usually carried out before any other scans to check for fractures or deterioration
  • CT scan — uses X-rays and a computer to create images of the inside of your body; this can detect bone problems and subtle fractures
  • MRI scan — uses radio waves and a powerful magnet to create 3D images of the soft tissues in your body; this can detect damage to your muscles and cartilage 

  If your GP suspects osteoporosis, they'll recommend a bone density scan.

There are things you can do at home to reduce your knee pain. This includes: 

• Applying ice packs or frozen peas wrapped in a tea towel — apply the ice pack for up to 20 minutes every two to three hours
• Applying heat packs — this can provide temporary relief
• Elevating your leg eg using pillows or sitting in a recliner
• Resting your knee — put as little weight on your knee as possible eg avoid standing for long periods of time
• Taking over-the-counter painkillers eg paracetamol
• Using compression bandages — these are breathable, lightweight, self-adhesive bandages and help prevent fluid build-up; they should not reduce the blood supply to your knee

Call 111 now if:

• You have a fever, feel hot and shivery, and have redness or warmth around your knee — you may have an infection
• Your knee is very painful
• Your knee is very swollen or has changed shape

It’s best to speak to your GP if you're experiencing prolonged knee pain. They will recommend treatment depending on the cause and severity of your knee pain. Treatments include: 

• Braces or arch supports
• Joint injections — these include: 
• Corticosteroids — this is not always effective but can reduce flare-ups caused by arthritis and reduce your pain
• Hyaluronic acid — a thick fluid similar to what is naturally found in your joints to lubricate them and consequently improve joint mobility and reduce your pain
• Platelet-rich plasma — this is effective for injuries, sprains and tendon tears; it reduces inflammation and helps healing 
• Pain relief medications
• Physiotherapy to strengthen the muscles around your knee and/or improve your technique if you play sports
• Surgery — this includes
• Knee arthroscopy
• Knee ligament surgery
• Knee replacement (total knee replacement)
• Patellofemoral replacement (partial knee replacement)

They may also recommend alternative medicine treatments, such as acupuncture or glucosamine and chondroitin tablets