The knee joint consists of three parts. Tricompartmental osteoarthritis occurs when arthritis symptoms affect all three parts.

Osteoarthritis of the knee can lead to degenerative changes in the joint. Because it affects the whole knee, tricompartmental osteoarthritis may be more severe than other forms of osteoarthritis.

Tricompartmental osteoarthritis affects around 17% of those with knee osteoarthritis, according to one 2021 review. Single compartmental osteoarthritis accounts for around 50% of cases, and bicompartmental osteoarthritis accounts for around 33% of cases.

This article looks at the symptoms, causes, diagnosis, and treatment options associated with tricompartmental osteoarthritis.

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Osteoarthritis commonly affects the knees. People sometimes call it wear-and-tear arthritis, as it happens when the cartilage in the joints breaks down over time.

Changes that cause damage over time are called degenerative changes. Symptoms will appear gradually and typically include stiffness, pain, and swelling in the knee joint due to a buildup of fluid.

Four bones meet at the knee. The tibia and fibula connect from below the joint. The femur connects from above, and the patella, or kneecap, sits just atop the femur and the connecting cartilage.

The meeting of these bones creates the three compartments in the knee:

  • the patellofemoral compartment, which is where the kneecap and femur meet
  • the medial femorotibial compartment, or the inside of the knee
  • the lateral femorotibial compartment, or the outside of the knee

Osteoarthritis can occur in any of these compartments, but tricompartmental osteoarthritis happens when it involves all three compartments.

People often consider tricompartmental osteoarthritis to be worse than other forms of knee osteoarthritis, as it affects the whole knee. Loss of cartilage or the synovium or joint lining may be more widespread.

Osteoarthritis causes the cartilage and synovium in the knee to wear down, often leading to bone spurs growing in their place. The cartilage may also get rough or break down completely.

This process worsens over time and often causes symptoms, including:

  • localized pain and inflammation
  • joint effusion, or water on the knee
  • chondrosis, wherein the soft or smooth cartilage breaks down
  • joint stiffness and difficulty moving the joint, especially after long periods of inactivity
  • bone spurs, or exostosis, in the knee that are visible on X-ray images
  • knees that lock up due to bone spurs
  • weakness or buckling in the knees
  • a change in gait, typically a knock-kneed or bowlegged walking gait

Symptoms may get worse after sitting or resting for a long period of time. Impact exercises may also cause more pain and swelling in the joint.

What are the warning signs of osteoarthritis of the knee? Find out here.

To diagnose tricompartmental osteoarthritis, a doctor may:

  • ask about a person’s symptoms
  • ask about their medical history
  • carry out a physical exam
  • do some tests

For example, they may ask if the person has symptoms such as:

  • cracking or popping sounds in the knee, known as crepitus
  • a grating feeling whenever they move the knee
  • stiffness in the morning or after resting that improves after 30 minutes
  • tenderness and swelling in the area
  • the bones feeling larger than before

Range of motion tests can show whether or not osteoarthritis has affected knee function.

Imaging tests, such as X-rays, can help confirm a diagnosis. The doctor will look for signs that cartilage has worn away or that bony growths have developed where the cartilage should be.

Osteoarthritis may be more challenging to diagnose in its early stages but easier to spot in later stages. This is because the physical changes become more evident over time.

If there is still any doubt, the doctor may recommend a soft tissue scan using an MRI scanner to thoroughly check the ligaments, cartilage, and synovium.

What are the stages of osteoarthritis of the knee? Find out here.

Osteoarthritis can occur from normal wear and tear of the joints, so anyone could potentially receive a diagnosis of the condition. However, some risk factors may make diagnosis more likely.

Age

Osteoarthritis can affect people at any age. However, it is more common among older adults. Some research suggests that it affects 33% of people aged 60–70 years and 43.7% of those aged over 80 years.

Staying active, stretching, and doing low impact exercises — such as tai chi, yoga, and swimming — may help keep the muscles strong and slow down degeneration as someone ages.

Obesity

Carrying extra weight can be hard on the joints, especially on the hips and knees, which are stress bearing joints. Losing weight may help ease the impact on the joints and reduce the symptoms.

A 2014 study indicated that losing 10% of one’s body weight may reduce symptoms such as pain and increase the physical function in the joint.

If a person with osteoarthritis also has overweight or obesity, current guidelines recommend losing some weight to help ease the condition.

Genes

Genetic factors may also play a role. Someone with a close family member who has or had osteoarthritis may be more likely to experience it themselves.

Sex

A 2015 review suggested that sex and hormones might play a role in osteoarthritis. The authors noted that women seemed more likely to experience knee osteoarthritis than men, though it is unclear why this happens.

Symptoms may be more likely to appear during menopause, leading researchers to believe that hormones, such as estrogen, may play a role.

Physical stress

According to the same 2015 review, physical activity that places pressure on the knees may be a risk factor for more wear-and-tear damage.

Doing manual labor, carrying heavy loads, or doing high impact exercises such as running may be risks for some people over time.

Traumatic injuries

The same review also points out that sustaining injuries directly to the knee or in an area that indirectly affects the knee, such as the foot or leg, may be an influencing factor in osteoarthritis symptoms later in life.

Features present at birth

Some people may be born with features in the bones, cartilage, ligaments, or synovium that make them more likely to experience symptoms of osteoarthritis later in life.

Other conditions

The risk may be higher in those who have cardiovascular and respiratory disease, especially if they also have a sedentary lifestyle.

There is some evidence to suggest that depression is also more common among those with osteoarthritis of the knee, according to the 2015 review.

There is currently no cure for osteoarthritis because it is not possible to replace cartilage once it has eroded.

Treatment for tricompartmental osteoarthritis usually involves managing the symptoms, preventing the progression of the condition, or undergoing surgery. A person’s options will partly depend on how severe their symptoms are.

Some treatments that may help include the following:

  • using over-the-counter (OTC) nonsteroidal anti-inflammatory drugs or acetaminophen
  • taking prescription medications if OTC remedies do not help
  • receiving corticosteroid injections to reduce inflammation, if a doctor recommends them
  • following a program of low impact exercises, such as swimming or tai chi
  • trying physical therapy
  • losing weight, if appropriate
  • applying heat or cold packs
  • undergoing cognitive behavioral therapy
  • using devices such as a walking cane to prevent falls or a sleeve or brace to support the knee
  • undergoing surgery, in some cases

How can injections help manage osteoarthritis of the knee? Find out here.

Some people use supplements, such as fish oil or glucosamine. However, current guidelines do not recommend using supplements, as there is not enough evidence to show that they work.

Surgery for tricompartmental osteoarthritis will often involve total knee replacement, or total knee arthroplasty. In this surgery, surgeons replace the damaged bone and joint with a plastic and metal joint.

It can take several months to recover from total knee arthroplasty. Having regular physical therapy sessions will help strengthen the legs and allow a person to walk normally again.

Is knee surgery a good idea? Find out here.

Osteoarthritis is a common but chronic degenerative condition. In tricompartmental osteoarthritis, symptoms affect the entire knee and may be more widespread than in other types of knee osteoarthritis.

There is currently no cure for tricompartmental osteoarthritis, but medical treatments and home remedies can help manage the symptoms.

Making appropriate lifestyle choices about diet and exercise may also help slow the progression of knee osteoarthritis. For some people, surgery can help restore function in the affected knee if other interventions do not work.

How can I improve the strength and stability of my knees? Find out here.