Bone cancer is more common in children and teens, but adults over 60 can also get it. People often mistake symptoms for growth spurts or arthritis. A doctor can do imaging tests and a bone biopsy to check.

While cancer itself can spread to your bones, primary bone cancers are relatively rare. They make up less than 1% of all cancer types. This includes bone cancer in the knee.

But given that many early symptoms of bone cancer may be similar to other conditions that affect your knee, it’s possible to mistake bone cancer in the knee for arthritis or other joint diseases.

Here’s what you need to know about bone cancer in the knee, including the types, symptoms, treatment options, and more.

Pain is the most common symptom of bone cancer. You may experience persistent pain in your knee that continues even during times of rest. Sometimes the pain may come and go. Over time, you might experience walking difficulties.

Other possible symptoms of bone cancer in the knee include:

Some of these symptoms, such as swelling and pain, are also common with other conditions, such as knee arthritis. People may also mistake these symptoms in children for growth spurts. It’s important to see a doctor for a correct diagnosis.

Which bones does bone cancer affect first?

While bone cancer may develop within any bone, it’s most common in long bones located in your legs and arms. It also frequently occurs in hip bones.

Bone cancer can be either primary or secondary. Primary bone cancer starts in your bones. Secondary cancer starts in another area and then spreads to your bones.

In adults, bone cancers are more likely to be secondary.

There’s also more than one type of bone cancer to consider. Each subtype below can affect your knee, but they also affect different cell types in your bones.

Osteosarcoma

Osteosarcoma is the most common type of bone cancer. It primarily develops in children and teens under the age of 20. But about 1 in 10 cases occur in adults over the age of 60. Osteosarcoma is also more common in males.

Osteosarcomas tend to occur in bones around your knee, like your upper shinbone or lower thighbone. They’re also common in the hips and arms and begin in early bone cells.

Chondrosarcoma

Unlike osteosarcoma, chondrosarcoma primarily affects adults over the age of 40. Experts consider it the second most common primary bone cancer behind osteosarcoma.

Chondrosarcoma starts in bone cartilage and is common in the legs, arms, and hips. But they can form anywhere you have cartilage, including your windpipe (trachea) or voice box (larynx).

Ewing sarcoma

Ewing sarcoma is another type of bone cancer that primarily affects adolescents, teens, and young adults. It mostly develops between 10 and 20 years of age, with white people more susceptible.

Also called Ewing tumors, this type of bone cancer is rare in adults over the age of 30. While it may develop in long bones of the leg, Ewing sarcoma can also occur in the chest, spine, and hips.

Secondary cancers

Some bone cancers of the knee may be secondary. This means they result from the spread of another type of cancer. One example is multiple myeloma, a cancer of plasma cells in your bone marrow.

Bone cancer in the knee is diagnosed with the following:

  • A physical exam: During the exam, a doctor will also look for any lumps or swelling.
  • Symptom history: A doctor will also ask you how long you’ve been experiencing symptoms in your knee, when they occur, and whether they’re persistent.
  • Imaging tests: These include X-rays, CT scans, and MRIs, which provide detailed pictures of your knee area to look for signs of bone cancer and possible signs of spreading.
  • Bone biopsy: This involves taking a small sample of bone tissue via needle aspiration, then sending it to a lab to look for cancer cells.

The exact treatment plan for bone cancer in the knee depends on the type and stage of cancer and whether it has spread to other areas of your body. In most cases, doctors may recommend a combination of the following treatments:

Surgery

Surgery for bone cancer in the knee may involve removing sections of the affected bone. A surgeon may then replace the bone or reconstruct it.

Chemotherapy

Chemotherapy involves medications intended to kill cancer cells in the body. Doctors may combine this with surgery in some cases.

Radiation therapy

Radiation therapy (or radiotherapy) may also treat bone cancer. Unlike chemotherapy, which involves medication, this treatment method uses radiation to kill cancer cells.

Other treatments

Other treatment options for bone cancer in the knee depend on the type of cancer. For example, a doctor may combine stem cell rescue with chemotherapy or radiation therapy for Ewing sarcoma.

According to the American Cancer Society, the 5-year survival rate for bone cancer is about 80%. That means you’re 80% as likely to live for 5 years or longer after diagnosis than someone who doesn’t have bone cancer.

But your exact outlook depends on your age, overall health, and the type of bone cancer you have.

The survival rate also depends on the stage of bone cancer at diagnosis. Cancer in more advanced stages is more difficult to cure because it has spread to other parts of your body.

The following are the 5-year relative survival rates for common bone cancers by stage:

StageOsteosarcomaChondrosarcomaEwing sarcoma
Localized (no spread)77%91%82%
Regional (nearby spread)65%75%70%
Distant (distant spread)26%23%39%

Bone cancer of the knee isn’t common. But if you experience ongoing pain in your knee, it’s important not to assume it’s arthritis or another knee-related condition.

Consider seeing a doctor for a diagnosis so you can obtain the appropriate treatment.