Tricompartmental osteoarthritis is a type of osteoarthritis that occurs in the knee. The knee can be divided into three compartments:

  • medial femoral-tibial compartment, found on the inside of the knee
  • patellofemoral compartment, formed by the femur and kneecap
  • lateral femoral-tibial compartment, found on the outside of the knee

Osteoarthritis (OA) can occur in any of the three compartments. When it occurs in all three, it’s referred to as tricompartmental osteoarthritis. Tricompartmental OA is generally considered to be a more serious form of OA of the knee because a larger number of joints are affected.

There aren’t symptoms that are unique to tricompartmental OA. Instead, you’ll experience symptoms of knee OA throughout all three parts of the knee joint. Symptoms of knee OA may include:

  • swelling and stiffness in the knee
  • difficulty bending and straightening the knee
  • increased inflammation with moderate to intense activity
  • pain and swelling that’s worse while sleeping or in the morning after getting up
  • pain increasing after sitting or resting
  • fragments of cartilage and bone jutting out, which can be seen on X-ray or get caught in joints, causing the joints to lock up
  • creaking, clicking, snapping, or grinding noise from the knee
  • weakness or buckling in the knee
  • impaired gait (walking), usually bow-legged or knock-kneed

You may be more likely to experience impaired mobility involving the knees as well.

Several factors increase your risk of developing OA, including tricompartmental OA. They include:

Obesity. Carrying excess body weight adds greater stress to weight-bearing joints, such as the knees. Research shows that weight loss of at least 10 percent of your body weight can improve symptoms of osteoarthritis.

Older age. As you get older, your joints can gradually wear away. Regular physical activity and stretching can help slow down this process.

Sex. Women are at higher risk of developing osteoarthritis, though the reasons for this are not well-understood.

Genetics. If a close family member, such as a parent, has osteoarthritis, you’re more likely to also have OA.

Injuries to the joint. Prior injuries to your knee increase your risk of developing osteoarthritis.

Bone and soft tissue deformities. Some people are born with knee joints and cartilage that are more prone to osteoarthritis.

Certain activities. Over time, certain forms of physical activity — without recovery — can stress the knee joints. Examples include working in manual labor jobs and running.

Your doctor will want to know about your symptoms. The criteria for a diagnosis of OA of the knee includes knee pain and three or more of the following symptoms:

  • stiffness in the morning lasting up to 30 minutes
  • cracking or grating feeling in the knee, known as crepitus
  • enlargement of the bony part of the knee
  • tenderness of the knee
  • lack of warmth on the joint
  • being 50 or older

Diagnosis will also likely include X-rays (sometimes called radiographic images). A medical assistant will usually take three or more images of the knee or knees. The orthopedist will then review the images. They will look carefully to see the space between the bones of the knee joint. Small spacing indicates that more cartilage has eroded and that OA is severe. They will also look for the formation of bony growths called osteophytes. Osteophytes are a result of bones rubbing against each other. In earlier stages of OA, they may not be visible on X-rays. However, because tricompartmental OA is generally quite severe in nature, these features are usually clear.

An orthopedist may also perform lab tests to rule out other diagnoses or take an MRI to get a clearer picture of soft tissues, such as cartilage and ligaments.

There’s no cure for tricompartmental osteoarthritis, or any other form of OA in the knee or elsewhere. That’s because there is not currently a way to replace cartilage once it has degraded. Instead, treatment focuses on managing symptoms. Less invasive methods are called conservative treatments. They include:

Lifestyle modifications that reduce the stress on your knee. Examples include switching from high-impact exercises, like running, to low-impact ones, like swimming.

Medical devices, such as canes, braces, shock absorbing shoes, and knee sleeves. These devices may help reduce the amount of pain in the knees.

Applying ice and heat.

Ointments. Your doctor may prescribe a cream that can be topically applied to relieve pain.

Over-the-counter pain relievers such as acetaminophen (Tylenol).

If conservative treatments aren’t effective, or if your condition continues to worsen, your doctor may prescribe medication that can be taken orally or injected. These may include:

  • prescription-strength nonsteroidal anti-inflammatory drugs (NSAIDs)
  • COX-2 inhibitors, which are a type of NSAIDs only available by prescription
  • corticosteroids, which are injected into the knee
  • viscosupplementation, which are injections put into the knee over a one-month period
  • narcotic pain relievers, which may relieve severe pain but can be addictive and they are now being prescribed less frequently

If those treatments are ineffective or stop working, your doctor may recommend surgery. Surgery is usually reserved for people with intense and persistent pain and where daily activities are significantly impaired. Because tricompartmental OA affects the whole knee joint, the type of surgery your doctor will likely recommend is total knee arthroplasty, which is also known as a total knee replacement. This procedure involves removing the damaged bone and cartilage and replacing it with a metal or plastic joint. This ultimately restores function with only few limitations. It generally takes up to three months to get back to normal activities after total knee replacement surgery. Recovery is accompanied by pain-relieving medication and regular appointments with a physical therapist.

Learn more: Before total knee replacement surgery »

Knee osteoarthritis is common. Tricompartmental knee OA is a special form that impacts all components of the knee joint, as opposed to just one or two. There are a variety of methods you can use to manage pain, ranging from nonsurgical to surgical. Additionally, you can prevent or slow down its onset by maintaining a healthy lifestyle.

If you have tricompartmental osteoarthritis, managing your condition can help prevent it from getting worse. Here are some ways to do so:

  • maintain a healthy weight
  • perform low-impact exercise such as yoga, swimming, and bike-riding
  • get sufficient vitamin D and calcium
  • avoid smoking
  • limit alcohol consumption to no more than one drink a day for women and two drinks a day for men