My Knees Hurt: What Are the Most Common Knee Pain Causes?

By: Tanuj Palvia, MD.

Unbeknownst to many folks, I used to be significantly overweight up until my teenage years. As a result, my knees suffered premature wear, and now that I am about to hit my 40s, I am reminded of my chunky past more than ever! And even though the knee sounds anatomically mundane, in diagnosing myself I came to learn the knee is actually a very amazing mechanical unit, and its fitness and maintenance are crucial to our everyday lives.

First, it is important to understand the anatomy. The knee is a complex structure consisting of four bones—the thigh bone called the femur, the shinbone called the tibia, a tiny bone behind it called the fibula, and the kneecap also known as the patella. There are strong ligaments and tendons that function as straps to hold these bones together. Additionally, there is cartilage beneath the kneecap and between the bones to cushion and stabilize the knee. Damage to any one of the structures listed above can be responsible for knee pain.

Knee Pain Causes

Here are the most common knee pain causes:

  • Osteoarthritis: Usually osteoarthritis or rheumatoid arthritis. Osteoarthritis implies a degenerative process that results from the “wear and tear” of the cartilage in the knee. Though common in folks over the age of 50, younger folks (such as myself!) can also experience this if there is a premature erosive process to the cartilage, such as that resulting from obesity.
  • Rheumatoid Arthritis: Arthritis can also result from rheumatoid arthritis, whereby the body’s immune system antibodies begin to attack and destroy the cartilage in the joint. In addition to pain, swelling, redness, and warmth over the kneecap may develop. Unlike osteoarthritis, knee pain from rheumatoid arthritis tends to improve with activity.
  • Knee Ligament Injuries: A ligament is a structure that holds bones together within a joint. In the knee, there are four primary ligaments in your knee—two collateral ligaments (found on either side of the knee) and two cruciate ligaments (which cross each other centrally in the joint and therefore serve as the primary essential anchors for stabilization).
    • Injury to the medial collateral ligament (MCL) often results from a direct blow to the outside of the knee, which causes knee pain inside the knee.
    • A blow to the inside of the knee may cause a lateral collateral ligament (LCL) injury, which causes pain to the outside of the knee.
    • Anterior cruciate ligament injuries are the most common type of knee injury, often resulting from a direct blow or a sudden change in direction or speed when running.2 Usually, a “popping” noise is heard, along with sudden swelling, and a giving out of the knee.
    • Posterior cruciate ligament injuries are uncommon and are generally caused by some sort of high-energy force to the knee (for example, a bent knee colliding with the dashboard during a car accident)
  • Meniscus Tear: There are two crescent-shaped thicker pieces of cartilage that sit right above the shin bone and provide cushioning for the overlying femur, almost as shock absorbers. Tearing of the meniscus is common in younger patients often during sports, or in the elderly as the cartilage weakens with age. A person with a meniscus tear may initially hear a “pop” when the tear occurs. This is followed by a gradual development of knee stiffness and swelling, along with knee clicking, locking, or catching.
  • Patellofemoral Syndrome: a very common injury amongst adolescents, it is usually caused by vigorous activities like running, squatting, or climbing stairs. that put stress on the knee, specifically on the cartilage behind the knee cap. Oftentimes, people with this condition describe a dull aching pain felt underneath the kneecap that becomes sharp with activity.
  • Prepatellar Bursitis: when the bursa, a flail filled sac that is positioned in front of the knee cap, becomes inflamed— is most commonly caused by people who frequently kneel, like gardeners or carpet layers.
  • Baker’s Cyst: A Baker’s cyst is swelling in the back of the knee joint, usually associated with another underlying problem such as a meniscus tear. Usually, a tightening pain is felt in the back of the knee and is often associated with knee stiffness and a palpable bulge that worsens with activity.
  • Iliotibial Band Syndrome: Refers to inflammation of the iliotibial band—a thick collection of fibers that runs along the outside of the thigh. Iliotibial band inflammation commonly happens as a result of overuse, especially in runners, and causes an aching, burning pain on the outside of the knee joint. Sometimes, the pain spreads up the thigh to the hip.

A knee pain diagnosis first requires a focused medical history by a medical professional. When I interview someone for knee pain, I wish to identify the quality of pain (such as aching, sharp or burning), the location, the chronology, and any pertinent history that may have contributed. Physical exam and imaging (X-ray/MRI) can help confirm a diagnosis. This is most important, as understanding the precise cause of knee pain is key to the formulation of an effective knee pain treatment plan —one that optimizes the relief of symptoms and the return to normal function. If you’re suffering from knee pain and would like us to guide you through a treatment plan, reach out to us by phone or fill out the form below.

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