Wear and tear of your knee over time can cause pain when bending your knee due to damage to the bones, ligaments, muscles and/or tendons in and around your knee joint.
For roughly every 500g of body weight, about 3kg of pressure is applied to your knees when they are bearing weight eg when bending, running, squatting or walking.
What does a knee injury feel like?
Depending on the underlying cause, a knee injury can cause sharp, shooting pain, a dull ache or a burning pain. You may notice swelling and your knee may feel tender to touch. You may also have difficulty bending, straightening or bearing weight on your knee and may find that your knee gets stuck (locks). A knee injury can also make you feel as if your knee is about to give way when you try to walk on it.
What causes knee pain?
The most common causes of knee pain include:
- Meniscus tears — tears to the C-shaped pieces of cartilage in your knee, which are called menisci
- Runner's knee — dull pain at the front of your knee (patella) also known as patellofemoral pain syndrome
- Sprained ligaments
- Tendonitis — inflammation of your tendons
Old knee injuries that weren’t treated correctly can also cause chronic (long-term) knee pain or knee pain that flares up occasionally.
Most common causes of knee pain
Other common causes of knee pain include:
- A dislocated kneecap
- Iliotibial band syndrome — burning pain on the outer side of your knee that can spread to your hip or thigh and is caused by inflammation; it commonly occurs in runners
- Knee bursitis — inflammation of the fluid-filled cushions (bursae) in your knee joint, which causes swelling, warmth and pain
- Osgood-Schlatter disease — a condition that causes pain and swelling at the point where the patellar tendon meets the top of your shinbone
- Osteoarthritis — a type of arthritis caused by wear and tear of your joints over time, which causes pain, swelling and stiffness that is worse in the morning
- Patellar tendonitis — inflammation of the patellar tendon, which connects your kneecap (patella) to your shinbone; this causes burning pain just below your kneecap
Iliotibial band syndrome, knee bursitis, runner’s knee, osteoarthritis and patellar tendonitis can also cause knee pain when bending. Other causes of knee pain when bending include:
- Baker’s cyst — swelling at the back of your knee caused by an accumulation of the fluid that lubricates your knee joint (synovial fluid); this can cause swelling and tightness
- Hamstring tendonitis — inflammation of your hamstrings that causes pain behind your knee and thigh
- Knee injury that damages the knee joint or ligaments — this will usually cause sharp pain and swelling, which makes it difficult to move your knee
- Quadriceps tendonitis — inflammation of your quadricep tendons that causes pain above or at the front of your knee
Pain behind knee when bending
If your knee pain when bending occurs behind your knee, the most likely causes are a Baker’s cyst, hamstring tendonitis or a knee injury.
Sharp pain in knee when bending
If your knee pain when bending is sharp, the most likely causes are a torn ligament or meniscus, fracture of one of the bones of your knee joint, osteoarthritis or patellar tendonitis.
Pain at the top of kneecap when bending
If your knee pain when bending occurs above your knee, the most likely causes are knee bursitis, osteoarthritis and quadriceps tendonitis.
Diagnosis of inner knee pain
Your doctor will ask you about your symptoms and when they started, as well as your medical history. They will also carry out a physical examination of your knee to check for swelling and instability, as well as to assess the range of movement in your knee.
They may then recommend imaging tests such as an X-ray or MRI scan to more closely examine the bones and tissues of your knee. They may also recommend blood tests to check for conditions such as rheumatoid arthritis and infections.
Treatment for knee pain when bending
Changing exercise and activity
Avoid high-impact activities as these put greater strain on your knee joints. Instead, try low-impact activities such as cycling, swimming, walking and water aerobics.
RICE method
RICE stands for:
- Rest — avoid bearing weight on your knee so tissues in your knee can heal
- Ice — apply a bag of ice wrapped in a towel to your knee for up to 20 minutes three to four times a day
- Compress — use compression bandages to wrap your knee but make sure you don’t wrap your knee too tightly as this can reduce its blood supply and cause more damage
- Elevate — whenever possible, elevate your knee above the level of your heart to reduce swelling
Heat
If your knee pain is caused by arthritis or you have a stiff knee, applying heat can help by improving your blood flow.
Medication for knee pain
Over-the-counter painkillers (eg paracetamol) and non-steroidal anti-inflammatory drugs (eg ibuprofen) can help reduce knee pain and swelling.
Massages
Massage can help relieve knee pain. However, you should see a doctor first before trying massage to find out if it is appropriate given the underlying cause of your knee pain.
Knee exercises
It is important to keep your knees active so the muscles that support your knee do not become weak — this can place greater strain on your knees. Knee strengthening exercises that target these muscles can, therefore, help reduce knee pain.
How to prevent knee pain when squatting and bending
It isn’t always possible to prevent a knee injury and subsequent knee pain. However, you can reduce your risk by making sure you always stretch your legs before and after exercising, and stop exercising if you feel any knee pain. You should also avoid suddenly increasing the intensity of your exercise regime and instead gradually work your way up.
Practicing regular strengthening and stretching exercises that target the muscles that support your knees can also reduce your risk of a knee injury.
If you are overweight, losing excess weight will reduce the strain on your knees, making a knee injury less likely.
If your work involves kneeling down a lot, use knee pads to reduce your chances of developing knee bursitis. Finally, make sure you wear well-fitting, supportive shoes.
Knee pain when bending FAQs
How do I know if my knee pain is serious?
If you are in extreme pain, or your knee is swollen, bleeding or deformed, then you may have a serious injury and should see a doctor. You will also need to see a doctor if you heard a popping sound when injuring your knee, you can't bear any weight on your knee, can't straighten your knee, or your knee is unstable or buckles when you try walking.
How do I stop my knees from hurting when I squat?
If you have knee pain when squatting, it is important to give your knees a rest so they have time to heal from any damage that has occurred. You can also apply ice packs for up to 20 minutes three to four times a day, wear compression bandages and whenever possible, elevate your knee to above the level of your heart. If these measures don’t improve your knee pain when squatting, see your GP.
Should I squat with knee pain?
If squatting is causing you knee pain, stop. You can try other knee strengthening exercises and work your way back up to squats. If you think you have injured your knee, see your GP.
Is squatting bad for knees?
Squatting done correctly is not bad for your knee and can actually help strengthen the muscles that support your knees, which will reduce your risk of a knee injury. However, if you have knee pain, you should first see your GP to investigate the underlying cause and get treatment if needed, before trying squats.
