Understanding Knee Pain

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The Anatomy of Your Knee

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The knee is the largest joint in the body and is central to nearly every daily activity, from standing and walking to bending and lifting. This joint is made up of three primary bones: 

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• The lower end of the thigh bone, or femur. 

• The upper end of the shin bone, or tibia. 

• The kneecap, or patella. 

 

Strong, tough tissue bands called ligaments connect the bones providing stability and keeping the knee properly aligned. The ends of each bone are coated with a layer of smooth, plastic-like cartilage, which minimizes friction, allowing for fluid and almost frictionless movement while absorbing impact to protect the bones. Cartilage also serves as a shock absorber, cushioning the bones from the forces between them.

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Lining the joint is a soft tissue called the synovium, which produces a lubricating fluid that minimizes wear by keeping the joint well-oiled. Together, these components enable smooth motion, shock absorption, and stability during movement. 

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Major Types of Knee Pain 

 

Knee pain can arise from various types of arthritis, each impacting the knee in unique ways:

  

Osteoarthritis (OA) is sometimes called degenerative arthritis because it is a "wearing out" condition involving the breakdown of cartilage in the joints. As the cartilage wears away, bones begin to rub directly against each other, causing pain, stiffness, and often swelling, making movement difficult. 

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Rheumatoid Arthritis (RA) produces chemical changes in the synovium (the lining of the joints) that causes it to become thickened and inflamed. In turn, the synovial fluid destroys cartilage. The end result is cartilage loss, pain, and stiffness. 

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