The knee is the largest joint in the body, and it is also one of the most complex. The knee joint is made up of four bones, which are connected by muscles, ligaments, and tendons. The femur is the large bone in the thigh. The tibia is the large shin bone. The fibula is the smaller shin bone, located next to the tibia. The patella, otherwise known as the kneecap, is the small bone in the front of the knee. It slides up and down in a groove in the femur (the femoral groove) as the knee bends and straightens.

Not only is the knee the largest joint in the body, but it also holds almost the entire human body weight, making it susceptible to injuries. A variety of factors can cause knee pain and knee injury, which include frequent heavy lifting, body weight, sports, and/or older age.

The most common knee conditions are:


The knee is one of the most common joints affected by osteoarthritis. The word arthritis means inflammation (swelling) of a joint. Osteoarthritis, also known as the “wear and tear” arthritis, is the most common type of arthritis.

Osteoarthritis affects the articular cartilage in the knee. Articular cartilage is the smooth coating that covers the surface of the bones inside the knee. Articular cartilage also cushions and helps lubricate the joint surfaces (see the anatomy section for further information about articular cartilage). In osteoarthritis, the articular cartilage begins to degrade. Over time, the articular cartilage can thin or form cracks. Pieces of cartilage may come loose and float inside the knee, further irritating the joint. After a long period of time, the cartilage can become completely “worn away,” and the bones begin to rub together.

Osteoarthritis usually comes on slowly and results in knee pain, stiffness and/or swelling. Sometimes a grating sound can be heard when the knee is bent – such as when climbing up and down stairs or crouching. Bumps or nodes may appear around the knee joint. Sometimes a knee can have a mild amount of osteoarthritis and feel perfectly fine.

Most types of treatment for osteoarthritis of the knee work best when started early before there is a lot of “wear and tear” in the knee. For this reason, establishing a correct diagnosis is very important. In some cases, osteoarthritis of the knee can be diagnosed based on the medical history and physical examination of the affected joint(s). An x-ray may be ordered to determine how much joint damage there is. Sometimes blood tests or joint fluid tests are ordered to confirm the diagnosis or to distinguish between different types of arthritis.

No one knows for sure what causes osteoarthritis but some risk factors include:

  • Previous knee injury (e.g., meniscal tear, ligament injury)
  • Family history of osteoarthritis
  • Being overweight
  • Damage to the knee from another type of arthritis
  • Increasing age

A lot can be done to help people who have osteoarthritis in their knee(s). The goal of treatment is to reduce pain, control swelling and maintain or improve mobility of the knee but unfortunately, there is no known cure for osteoarthritis.

What is the treatment for a knee injury?

Most knee injuries can be treated non surgically. However, until the condition is diagnosed, the proper treatment cannot be determined. During an appointment, your doctor will perform a knee examination and may take x-rays, an MRI, or prescribe physical therapy or other treatments.

Contact Us

If you have any of the following symptoms, please call to schedule an appointment:

  • Limited range of motion in your knee
  • Stiffness after long periods of sitting or lying down
  • Swelling or tenderness
  • Grinding sensation in your knee
  • Steady pain in your knee

Dr. Joshua Matthews is a fellowship-trained orthopedic surgeon specializing in sports medicine and minimally invasive arthroscopic surgery of the knee and shoulder. He completed his fellowship training in arthroscopy and sports medicine in San Diego, California. Dr. Matthews’ specialties include.

Please call FORM Ortho at (510) 585-2545 to schedule an appointment.