Arthritis is a group of more than 100 conditions that cause joint pain and inflammation. The most common type, osteoarthritis, is caused by the breakdown of cartilage on the ends of bones in a joint.

More than 32.5 million adults in the United States have osteoarthritis, and it becomes more common with age. Mild osteoarthritis can often be treated with weight loss, exercise, and over-the-counter (OTC) medications. Severe arthritis may require surgery.

Osteoarthritis is divided into two categories: primary and secondary. Primary osteoarthritis occurs as a result of degenerative changes to the cartilage without a known cause. Secondary osteoarthritis occurs in the presence of a preexisting condition.

Read on to learn more about the differences between primary and secondary osteoarthritis.

Doctors classify osteoarthritis as primary when it has no known cause, and they classify it as secondary when the cause is an underlying injury or condition.

Primary osteoarthritis is more common than secondary. It tends to develop over time as a result of joint wear and tear and to affect adults over age 65. It often occurs in multiple synovial joints.

Synovial joints are joints that have a cavity filled with fluid between two bones. Osteoarthritis most commonly develops in the following joints:

  • hands
  • hips
  • lower back
  • neck
  • knees

Osteoarthritis develops when the cartilage that covers the ends of your bones breaks down. This causes the ends of the bones to rub against each other, leading to symptoms such as pain, stiffness, and loss of mobility.

Primary osteoarthritis

Primary osteoarthritis is also called idiopathic osteoarthritis. “Idiopathic” means that the cause is not clear. But even though the exact cause remains unknown, researchers have identified some risk factors that increase the odds of developing the condition.

For example, risk factors for primary hip osteoarthritis include:

  • increasing age
  • genetics
  • obesity
  • previous fracture
  • repetitive stress
  • occupations involving heavy manual work
  • high impact sports

Secondary osteoarthritis

Secondary osteoarthritis occurs when a preexisting condition leads to the breakdown of cartilage in a joint. It usually occurs as a result of trauma or misalignment of a joint.

Your doctor may suspect secondary osteoarthritis if you develop osteoarthritis in a joint in which it typically does not occur.

Many conditions can cause secondary arthritis, including:

Other forms of arthritis can also contribute to the development of secondary osteoarthritis.

For example, in a 2017 study, researchers found that men with a type of arthritis called ankylosing spondylitis had a significantly higher risk of developing osteoarthritis and needing total hip or knee replacements.

Researchers estimate that about 3.3% to 3.6% of the world’s population has osteoarthritis. Additionally, an estimated 80% of U.S. adults over 65 have signs of osteoarthritis as seen with an X-ray, but only 60% of these people have symptoms.

Risk factors for osteoarthritis include:

  • joint injury or overuse
  • obesity
  • being a woman — particularly a woman older than 50
  • increasing age
  • family history
  • ethnicity — some Asian populations have a lower risk

Other factors that may contribute to the development of osteoarthritis include:

  • muscle weakness
  • joint injury
  • overuse
  • physically strenuous occupation
  • low quadriceps strength
  • low sex hormone levels
  • low bone density
  • inadequate diet

If you receive an osteoarthritis diagnosis, your doctor can help you make a treatment plan. Generally, your doctor will recommend starting with conservative treatments like nonsteroidal anti-inflammatory drugs (NSAIDs) and changing your activity habits, if necessary.

Potential side effects of NSAIDs include:

  • gastrointestinal bleeding
  • ulcers
  • chronic renal insufficiency

Additionally, acetaminophen (Tylenol), an OTC analgesic, is often recommended for OA. It does not have some of the side effects that NSAIDs do.

Lidocaine patches and topical NSAID creams or gels — like voltaren or diclofenac — are other OTC treatment options.

If conservative treatments aren’t improving your symptoms, your doctor may recommend prescription pain medications, injections, or surgery as a last resort.

Your doctor can also evaluate you for other health conditions that may contribute to the development of osteoarthritis. Some conditions that affect your whole body, such as gout and diabetes, can predispose you to joint problems.

Osteoarthritis doesn’t have a cure, but certain changes and medications can help ease symptoms.

Weight loss and exercise

If you have obesity or overweight, your doctor may recommend that you try to lose weight to take some stress off your joints. Losing weight is also strongly associated with a decreased risk of developing diabetes. Diabetes can contribute to joint problems.

Regular exercise can help strengthen your muscles and joints and assist with weight loss.


Your doctor may recommend OTC medications such as:

If these aren’t effective, they may recommend steroid injections. These injections contain a medication similar to the hormone cortisol that helps reduce inflammation and pain for weeks or months.

Supportive treatments

Your doctor may also recommend supportive treatments to reduce pain. These can include:


Surgery is usually necessary only in severe cases of osteoarthritis, when other treatments are not effective. Doctors may use the following types of surgery to treat osteoarthritis:

  • Joint fusion: This procedure involves fusing the bones on either side of a joint to reduce pain. Afterward, you will no longer be able to move the joint.
  • Joint replacement: In this procedure, a surgeon will replace your affected joint with a prosthesis made of plastics and metal.
  • Osteotomy: Osteotomy is used to treat knee and hip osteoarthritis. It involves adding a small section of bone from above or below your knee or hip to alleviate symptoms.

Osteoarthritis is a type of arthritis characterized by the breakdown of cartilage and other tissues in a joint. It can be categorized as either primary or secondary osteoarthritis. Primary osteoarthritis has no known cause, while secondary osteoarthritis is caused by a preexisting disease, injury, or misalignment.

Osteoarthritis becomes more common with age. If you’re dealing with persistent joint pain, it’s a good idea to consult a doctor for a proper diagnosis. Your doctor can recommend treatment strategies to help reduce pain and manage your symptoms.