Common Causes of Knee Pain

Knee pain is very common and can sometimes be exhausting. Many things cause knee pain, including medical conditions, trauma, and injuries from overuse of the joints.

The key to proper knee pain treatment is knowing the root causes of the pain. Then the healthcare provider can make the right treatment plans.

In this article, we will learn about the common causes of knee pain.

Common Causes of Knee Pain

The knee is a complex structure with three main bones:

• The lower part of the thigh bone.

• The upper part of the shin bone.

• Kneecap.

Ligaments and tendons connect these bones together. The cartilage under the kneecap acts as cushions to hold the bones in place and stop friction, helping them work smoothly. Any damage or disease in these parts can cause knee pain.

Common causes of knee pain include:-

1- Knee arthritis.

2- Knee ligament injuries.

3- Torn meniscus.

4- Patellar tendonitis and tears.

5- Patellofemoral pain syndrome.

6- Baker cyst.

7- Prepatellar bursitis.

8- Iliotibial band syndrome.

1. Knee arthritis

Several types of arthritis can affect the knee joint, causing varying levels of pain, swelling, and disability, Some of them are common, such as:

• OsteoarthritisKnee osteoarthritis develops due to cartilage wear and is more common in people over 50. It may start as sharp pain when moving.

• Rheumatoid arthritisRheumatoid arthritis is an autoimmune disease where the immune system attacks the joints, causing pain, swelling, redness, and warmth. The pain often feels better with activity.

• GoutGout happens when uric acid levels rise in the blood, forming sharp crystals inside the joint. It affects the knee, hip, fingers, especially the big toe, and can cause severe pain.

• Post-traumatic arthritisThis arthritis develops after a knee injury due to leftover damage, instability, or excessive wear.

2. Knee ligament injuries

There are four main ligaments in the knee. All of them connect the thigh bones to the shin bones. These ligaments and possible injuries include:

• Medial Collateral Ligament MCLThis ligament runs inside the knee toward the middle. A direct hit from outside the knee can cause pain inside the knee.

• Lateral Collateral Ligament LCLThis ligament runs on the outside of the knee. A hit from inside the knee can cause pain on the outer part of the knee.

• Anterior Cruciate Ligament ACLThis ligament goes diagonally across inside the knee joint, in front of the posterior cruciate ligament. A direct hit or sudden direction change while running can cause a pop, knee failure to stand or walk, imbalance, and severe pain.

• Posterior Cruciate Ligament PCLThis ligament runs diagonally across the inside of the knee joint, behind the anterior cruciate ligament. It can get injured from a big impact, like a car accident. This causes pain at the back of the knee and instability.

Anterior cruciate ligament injuries are the most common knee injuries, while posterior cruciate ligament injuries are the least common.

3. Torn Knee Cartilage (Meniscus)

The meniscus is a solid C-shaped piece of cartilage that absorbs shocks between the thigh and shin bones. There are two in each knee. It can tear from overloading or twisting the knee, which is a common cause of knee pain.

When the meniscus tears, you might hear a pop. Symptoms then come on gradually like popping, swelling, stiffness, feeling the knee locks, and trouble straightening it.

When young, injuries usually come from playing sports like soccer. As you get older, injuries are more likely due to age-related weakness.

4. Patellar Tendonitis and Tear

The patellar tendon is a big tendon connecting the kneecap to the shin bone. Patellar tendonitis often happens in athletes who run and jump a lot. It usually causes mild constant pain that gets worse when active.

Sometimes, a weak patellar tendon can tear, causing the following symptoms:-

• Sharp pain.

• Swelling in the knee.

• Feeling of tearing or popping.

If the tear is severe, the person may notice a dent below the knee, and the knee may not stand, walk, or work.

5. Patellofemoral Pain Syndrome

This syndrome is common in teens and young people, usually caused by intense activities that strain the knee, like running, squatting, and climbing stairs, also called runner's knee.

Also, patellofemoral pain syndrome can happen because of muscle imbalances around the hip and knee and not keeping the kneecap aligned.

Patellofemoral pain syndrome causes mild continuous pain in the front of the knee. The pain can get worse with activities like repeated knee bending or after sitting for a long time. You might feel a popping in the knee when going up stairs or standing up.

Swelling or locking of the knee is rare in patellofemoral pain syndrome.

Other common causes of knee pain

Some other common causes of knee pain can include:-

• Baker cyst:- This is swelling at the back of the knee joint. It can happen due to a meniscus tear and may cause severe pain from a cyst or fluid build-up behind the knee, which gets worse with activity.

• Prepatellar bursitisIt's a fluid-filled sac above the kneecap, can cause mild pain, and may result from kneeling a lot.

• Iliotibial band (ITB) syndromeIt's swelling of thick fibers on the outer side of the knee, often caused by overuse, causing sharp burning pain on the outside of the knee joint. Common in runners.

Less common causes of knee pain

Less common causes of knee pain include many medical conditions and injuries such as:

• Dislocated kneecapHappens due to sharp hits or twists on the knee making the kneecap slip out of place, causing severe pain at the front of the knee and twisting, slipping, or locking during movement.

• Kneecap fractureHappens due to a strong direct hit or falling on the knee. It causes pain, trouble straightening the leg, bruises, and swelling in the front of the knee. Sometimes there's a clear deformity.

• Plica syndromeIt's irritation of the synovial membrane (joint lining) causing pain in the middle and front of the knee. Pain can get worse even when resting, or when squatting, running, or kneeling. There might be a popping sound when bending the knee.

• Osgood-Schlatter diseaseThis affects kids and teens aged 9-14. It causes pain in the front of the knee that gets better with rest and worse with activities like running or jumping.

• Osteochondritis dissecansA rare condition in kids causing poor blood supply to parts of the bone and nearby cartilage in the joint. The knee can separate from the underlying bone and cause pain with activity.

• Knee joint infection:- Causes severe pain, swelling, warmth, painful movement, and fever. It may be due to a bacterial infection in the bloodstream.

• Bone tumor:- Bone tumors are rarely the cause of knee pain. Symptoms may include fever, unexplained weight loss, and pain that gets worse at night.

Source of the article.