Tricompartmental Osteoarthritis

Medically Reviewed by Tyler Wheeler, MD on August 28, 2022
Written by Paul Frysh
3 min read

Tricompartmental osteoarthritis is a type of arthritis that affects your knee.

In osteoarthritis, or OA, the smooth, slippery cartilage that covers the ends of your bones and helps them glide over each other slowly wears away. This allows bones to rub together at the joint. Typical symptoms like pain, swelling, stiffness, and loss of motion often get worse over time.

Age, injury, and repeated motion can all lead to osteoarthritis, the most common type of arthritis in the knee.

Tricompartmental refers to the three parts, or “compartments,” that make up your knee. There is some crossover between compartments:

  • The medial compartment includes the spot where your thigh bone meets your shin bone and the space around it on the inside of your leg (the side closest to the other knee).
  • The lateral compartment includes the spot where your thigh bone meets your shin bone and the space around it on the other side (outside) of your leg.
  • The patellofemoral compartment is made up of the space between your kneecap and your thigh bone.

When OA affects all three compartments, doctors call it tricompartmental osteoarthritis.

The main symptom of osteoarthritis in the knee is pain that worsens over time. It may be most uncomfortable and stiff in the morning when you wake up. You might not be able to move your knee as freely as you used to, and you may notice a scraping or crunching feeling (called crepitus).

Other symptoms might include:

  • Swelling
  • Trouble with stairs
  • More pain in rainy weather or after hard exercise
  • Difficulty straightening your leg all the way
  • A feeling of buckling in the knee
  • Appearance that your knees have shifted in (knock-kneed) or out (bow-legged)

Normal wear and tear is a big part of the reason you get osteoarthritis, especially after age 50. But an injury, or constant lifting, jarring, or bending also might cause it or make it worse.

Your genes, smoking habits, and body weight can also affect your risk for tricompartmental OA.

Your doctor will ask about your health history and symptoms. They might take a sample of your blood to check for levels that suggest arthritis. Imaging of your knee with X-rays or CT scan or MRI can help to zero in on the problem area and make a diagnosis, but they’ll also:

  • Test your knees’ range of motion
  • Feel for tenderness or bony lumps
  • Watch how you stand and walk

There are a number of things your doctor can do to manage osteoarthritis in your knees:

Surgical options might include:

  • Replacement of cartilage on the bone by grafting tissue
  • Replacement of all or part of the knee joint -- bone and cartilage (arthroplasty)

A study of overweight and obese adults with osteoarthritis of the knee showed that 1 pound of weight loss removes 4 pounds of pressure from the knee. Drop 10 pounds and you’ll take as much as 40 pounds of pressure off your knees, depending what type of activity you’re doing. That’s 40 fewer pounds of wear and tear on your knees every day, which could add up to a big difference over time.

It’s also a good idea to keep moving. Exercise won’t harm your joints and actually seems to help keep them healthy, as long as you don’t do the same motion too much or overstress a joint with an injury.

Talk to your doctor if you already have knee pain and you don’t want to make it worse. It may be better to avoid exercise in which you kneel, bend deeply, or run downhill.