Written by: Alexander Riordan, MD
What is arthritis? What does it look like? Read on to find out...
When bones meet at a joint, the surface is covered by specialized tissue called articular cartilage. This particular type of cartilage allows smooth, almost frictionless gliding of the joint when it is healthy and working normally. For example, in the knee articular cartilage is present at the bottom of the femur (thigh bone) and the top of the tibia (shin bone).
Unfortunately, articular cartilage can become damaged over time through wear and tear (osteoarthritis) or through inflammation (inflammatory arthritis such as rheumatoid or psoriatic arthritis). Osteoarthritis is the most common form of arthritis. As we age, cartilage can become thinner (much like losing the tread on your tires as your mileage increases).
As the damage becomes more severe, cracks and potholes in the cartilage can start to show up. These cracks and potholes might go all the way down to bare bone (the reddened areas in the model above). As the knee tries to move and glide, the potholes and cracks can catch in the knee and the nerves at the end of the bone transmit pain signals to the brain.
Since the cartilage that was protecting and cushioning the knee now wears away and becomes thinner, the bone starts to see more stress. In response, the body tries to make more bone for extra support, creating bone spurs (osteophytes). These osteophytes can be seen on x-rays. Additionally, we will see narrowing of the space between the bones on x-ray. This is because cartilage does not show up on x-ray, but the bones do. So, when the space between the bones becomes less and less, we know that the cartilage is thinning, and we diagnose arthritis. Other findings that can be seen in arthritis are small bone cysts and thicker bone right along the joint surfaces. The cysts show up as clear holes in the bone, and the thicker bone (sclerosis) shows up as a whiter surface to the bone on x-ray. The x-rays below compare a normal knee x-ray to one with severe arthritis.
The knee above with arthritis has progressed to bone-on-bone. This means the cartilage is completely gone in that area of the joint. Typically, this is very painful, and starts to decrease motion. Bone-on-bone arthritis is like completely blowing out a tire on your car and continuing to drive on the rims.
Interested in seeing if you have arthritis? Call us now at 414-332-6262 for an appointment! We will perform a digital x-ray at the time of your appointment and instantly be able to see what your knee looks like. Choose your provider here.
Already feeling arthritis pain? Read more about the right timing for a knee replacement by clicking here!