Knee Pain

Story

Connected to · 2

regulates · 2

Shoulder Pain
Joint cartilage has no nerves and no blood vessels, so cartilage itself does not hurt; shoulder pain more often comes from tendons, bursae and the joint capsule. Rotator cuff–related shoulder pain and jumper's knee (patellar tendinopathy) follow the same path of degeneration after overload: under the microscope there is disorganized collagen and repair that cannot keep up, not a crowd of inflammatory cells.
Plantar Fasciitis
Plantar fasciopathy and jumper's knee follow the same script of degeneration after overload: when load jumps suddenly, repair cannot keep up. The main line of treatment is heavy slow resistance and eccentric training to make the tissue stronger, not anti-inflammatories plus complete rest.

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What the knee is made of

EVIDENCEREVIEW 2

READ THE ORIGINAL

Articular cartilage has no nerves and no blood vessels. So the line the cartilage wore down, so it hurts fails on mechanism alone: a tissue with no nerves cannot produce pain. The alarm comes from the neighbors that do have nerves: the bone under the cartilage, an inflamed joint lining (synovium), the fat pad below the kneecap, and the joint capsule.

The knee is the body's largest weight-bearing joint. Three bones (the thigh bone, the shin bone, and the kneecap) form two sliding surfaces; cartilage caps the ends of the bones, and the menisci sit between them as cushions. Cartilage has no blood supply, so it depends on joint fluid being squeezed into it each time you bend and straighten, load and unload the knee. That makes the knee a machine maintained by movement, not a shoe sole that wears thinner with use.

Two situations fall outside this story: a knee that suddenly turns red, hot, and swollen with a fever needs the emergency department right away; rapid swelling after an injury, or not being able to put any weight on the leg, also needs prompt medical care.

Watch this step as a mechanism animationOpen mechanism

Educational content, not medical advice — consult a clinician.

Back

Knee Pain

Story

Connected to · 2

regulates · 2

Shoulder Pain
Joint cartilage has no nerves and no blood vessels, so cartilage itself does not hurt; shoulder pain more often comes from tendons, bursae and the joint capsule. Rotator cuff–related shoulder pain and jumper's knee (patellar tendinopathy) follow the same path of degeneration after overload: under the microscope there is disorganized collagen and repair that cannot keep up, not a crowd of inflammatory cells.
Plantar Fasciitis
Plantar fasciopathy and jumper's knee follow the same script of degeneration after overload: when load jumps suddenly, repair cannot keep up. The main line of treatment is heavy slow resistance and eccentric training to make the tissue stronger, not anti-inflammatories plus complete rest.

Read full story

Stop 1/6

What the knee is made of

EVIDENCEREVIEW 2

READ THE ORIGINAL

Articular cartilage has no nerves and no blood vessels. So the line the cartilage wore down, so it hurts fails on mechanism alone: a tissue with no nerves cannot produce pain. The alarm comes from the neighbors that do have nerves: the bone under the cartilage, an inflamed joint lining (synovium), the fat pad below the kneecap, and the joint capsule.

The knee is the body's largest weight-bearing joint. Three bones (the thigh bone, the shin bone, and the kneecap) form two sliding surfaces; cartilage caps the ends of the bones, and the menisci sit between them as cushions. Cartilage has no blood supply, so it depends on joint fluid being squeezed into it each time you bend and straighten, load and unload the knee. That makes the knee a machine maintained by movement, not a shoe sole that wears thinner with use.

Two situations fall outside this story: a knee that suddenly turns red, hot, and swollen with a fever needs the emergency department right away; rapid swelling after an injury, or not being able to put any weight on the leg, also needs prompt medical care.

Watch this step as a mechanism animationOpen mechanism

Educational content, not medical advice — consult a clinician.