Understand what a healthy knee looks like, how arthritis affects the joint, and what treatment options are available.
The knee is one of the largest weight-bearing joints in the body. It consists of three main compartments: the medial (inner), lateral (outer), and patellofemoral (kneecap) compartments.
In a healthy knee, smooth cartilage covers the ends of the femur and tibia, as well as the undersurface of the patella. This cartilage allows the joint to move smoothly while absorbing forces during walking and other activities.
Knee osteoarthritis occurs when the cartilage gradually deteriorates, resulting in joint space narrowing, inflammation, stiffness, and pain.
As the disease progresses, the cartilage may wear away completely, causing bone-on-bone contact and, in some cases, changes in the alignment of the leg.
A normal knee X-ray typically demonstrates:
An arthritic knee X-ray may demonstrate:
Weight-bearing X-rays are particularly useful because they demonstrate how the joint behaves under normal loading conditions.
Common symptoms include:
Symptoms may gradually interfere with daily activities, exercise, sleep, and overall quality of life.
Initial treatment generally focuses on relieving symptoms and maintaining function without surgery.
Options include low-impact exercise, strengthening and physical therapy, weight management when appropriate, anti-inflammatory medications, activity modification, and selected injections.
When arthritis becomes severe and nonsurgical treatments no longer provide adequate relief, knee replacement surgery may be considered.
Total knee replacement is a surgical procedure in which damaged cartilage and a small amount of underlying bone are removed from the joint surfaces.
The surfaces of the femur and tibia are then replaced with specially designed metal components. A durable polyethylene insert is placed between these components to allow smooth joint movement. The undersurface of the kneecap may also be resurfaced when appropriate.
The goal of surgery is to reduce pain, improve knee function, restore appropriate alignment, and help patients return to their everyday activities.
