Arthritis of the Knee
Nabil Ebraheim, M.D., Brent Steiner, M.D., Seth Phillips D.O.
Osteoarthritis is the most common cause of arthritis of the knee. The patient will complain of pain, swelling, stiffness, and decreased range of motion of the knee. In arthritis, the cartilage of the knee gets worn off. The meniscus, which absorbs the shock, becomes degenerated and tears. Over time, there will be more and more degeneration with wear and tear on the knee joint. Th joint space becomes narrower and narrower. When the cushion of the cartilage is completely lost, the bone will rub against bone, causing severe symptoms to the patient with severe pain, inability to walk, swelling and the knee may give way (knee will be unstable). The x-ray will show the arthritis.
When you ask the patient to stand or walk, the alignment of the lower extremity is lost, and the patient may have varus or valgus malalignment.
Ø VARUS = LEG BOWING IN
Ø VALGUS = LEG BOWING OUT
With varus deformity, the bowing end of the leg occurs more with osteoarthritis (common) and the patient will compensate for the arthritis and pain in the knee by limping (antalgic gait). The patient is trying to reduce the weight being placed on the knee. The stance phase on the affected knee will be shortened (the patient cannot take the pain any longer, so they are quick to get the foot off the ground due to the painful knee).
Arthritis can be mild, moderate, or severe. To understand arthritis, you need to know the anatomy of the knee. Identify the femur, tibia, patella (kneecap), articular cartilage, and meniscus. Synovial fluid lubricates the knee joint. At the end of the femur and the tibia, there is hyaline articular cartilage which is smooth and allows for smooth movement of the joint. There are no holes, no fissures, or cracks in the normal hyaline cartilage.
Mild Osteoarthritis of the Knee
Ø The patient will have some discomfort and the x-rays can appear normal.
Ø The fabric of the articular cartilage breaks down.
Ø The process of wear and tear, being overweight, and enzymes will affect the cartilage and the cartilage will break down (it is mild or minimal). The symptoms can be controlled by nonsteroidal anti-inflammatory medication, weight loss and therapy.
Moderate Osteoarthritis of the Knee
Ø There will be narrowing of the joint space on X-ray due to degeneration of the cartilage.
Ø There will be cysts in the subchondral space located underneath the cartilage and there may be some osteophytes or bone spurs.
Ø The joint will no longer be smooth (joint surface is roughened with cracks and fissures).
Ø The patient’s pain will be worse with more swelling.
This is the time when the physician has many options however none of them are optimal. You may try non-steroidal anti-inflammatory medication, weight loss, physical therapy exercises, steroid injection, viscosupplimentation or hyaluronic acid injections. Recently long-acting steroid injections can be used. Other doctors may try platelets and stem cells. None of the options are proven to be successful. The only protocol that has proven to be successful is a regimen of weight loss, exercise, and non-steroidal anti-inflammatory medications.
Severe Osteoarthritis of the Knee
Ø The condition of the knee is bad.
Ø The joint space is severely narrowed with complete destruction of the cartilage.
Ø The knee is swollen and painful with more osteophytes, the bone is rubbing against bone and no cartilage is left.
Ø There is no cushion and nothing to absorb the shock of the weight so the condition becomes very painful.
The patient’s knee can be compared to a car that is running on it’s rim. Meaning, that because the patient is walking on their own bone, there will be decreased mobility decreased activity in the patient will have an inferior quality of life. Surgery is the best option for the patient and is usually one in the form of a total knee replacement.
The total knee replacement is like a house that has a roof that leaked, and you want to change the roof of the house. You need to fix the damaged roof of the house to fix the destruction to the knee.
Thank you to Nathan Elkins, The University of Toledo, Ohio for the contribution to this work.