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What Causes Knee Pain?

Osteoarthritis is the leading cause of knee pain in the United States and the most common form of arthritis. It occurs when the joint cartilage and the bone underneath wears down over time. Studies estimate that over half of people will develop knee osteoarthritis over their lifetime.

First image: Healthy knee with evenly spaced gaps (no osteoarthritis).

Second image: Knee with inside compartment wear and tear (medial osteoarthritis).

Third image: Knee with full bone-on-bone wear and tear (medial and lateral osteoarthritis).

x-ray of knee x-ray of knee x-ray of knee

Osteoarthritis Knee Pain

A knee with osteoarthritis is not able to bend and function as well as a healthy knee. When osteoarthritis sets in the cartilage - a smooth and slippery tissue that covers and cushions the ends of bones - becomes frayed and wears away. Over time the progression of osteoarthritis can lead to increased pain and reduced mobility.

Osteoarthritis symptoms often include pain and stiffness. This is commonly described as an aching pain, like pain experienced after a long walk. Symptoms may be more noticeable in the morning or after a long period of rest. Osteoarthritis, known as "wear and tear" arthritis, often affects people in their middle-ages and beyond.

How Does Osteoarthritis Affect Your Knee?

Osteoarthritis develops slowly over many years, often causing pain that makes movement more difficult. If the cartilage wears completely away, bone-on-bone contact can occur. To make up for the lost cartilage when this occurs, the damaged bones may grow outward and develop painful deformities. The pain caused by osteoarthritis can range from mild to significant.

What Are The Leading Causes of Knee Osteoarthritis?

  • Age. Osteoarthritis typically affects people in their middle ages and beyond as cartilage loses its ability to heal or regenerate. An estimated 1 in 2 people will develop knee osteoarthritis by age 85.
  • Weight. The more you weigh, the more stress is placed on your knee joint. An estimated 2 in 3 people who are obese will develop knee osteoarthritis in their lifetime.
  • Heredity. Inherited traits such as bow leggedness, knock-kneed and double-jointed can put you at greater risk for osteoarthritis.
  • Injury. A knee injury that occurred earlier in life - such as in sports or at work - can eventually lead to osteoarthritis.
  • Repetitive stress. Occupation related movements, such as kneeling, heavy lifting and walking can lead to stress injuries in the knee and can make it more likely for osteoarthritis to develop.
  • Gender. Women are more likely than men to experience knee osteoarthritis. However, over 30 million American men and women collectively suffer from the disease.
  • Other illnesses. If you have had other problems with your knee, such as a knee infection or gout, the risk of osteoarthritis may increase.

Diagnosis and Treatment of Osteoarthritis

If you have knee pain and believe you have knee osteoarthritis, it is best to consult with a physician to determine what can be done. When you meet with one of our physicians, you will likely be asked when the symptoms started, whether they have gotten worse over time, and how you feel doing certain activities. The physician will likely ask about you and your family’s medical history. It is also common to perform a physical examination to check your knee reflexes and mobility.

X-rays will be ordered to confirm that you have osteoarthritis. X-rays can show how much osteoarthritis wear has occurred and whether the osteoarthritis is located in one area of the knee or if it has progressed to multiple areas.

Once it is determined you have osteoarthritis, there are many treatment options that can help manage the pain and keep you active. Here at Shasta Regional Medical Center, our physicians are dedicated to working closely with you to develop a personal treatment plan designed to help relieve your knee pain and stiffness.

1. Centers for Disease Control and Prevention, Arthritis-Related Statistics ,, Accessed 9.5.16