The knee is made up of three bones: femur (thigh bone), tibia (shin bone), and patella (knee cap). The knee joint has three main articulations or compartments, which are the between the femur and tibia on the inside and outside of your knee (medial and lateral compartments) and between the patella and femur (patellofemoral compartment). The ends of these bones are lined with a specialized tissue called articular cartilage. Cartilage does not have a blood supply, so when it is damaged or starts to break down, it does not grow back. The process of cartilage breakdown is called arthritis.
When cartilage loss starts to occur, inflammatory enzymes are released into the joint. These cause further breakdown until ultimately, the underlying bone is exposed. When bone rubs on bone, this causes significant pain and sensation of cracking in the joint. Pain often leads to limited range of motion and weakness, which can lead to difficulties with activities of daily living and decreased quality of life. Once conservative treatment fails to meet a patient’s expectations for pain tolerance and function, a total or partial knee replacement can be considered. This surgery can be very successful in alleviating pain and helping patients regain their quality of life.
The cartilage can break down in one, two, or all three compartments of the knee. When only one compartment is involved, patients may be a candidate for a partial knee replacement. However, when all of the compartments of the knee are involved, a total knee replacement leads to better outcomes.
- Knee stiffness and decreased range of motion
- Knee weakness from lack of use
- Pain at night
- Morning stiffness
- Audible cracking or popping upon movement
- Knee buckling
- Pain worsening over time
- Physical Therapy - A formal course of physical therapy (PT) is the first line of treatment. PT can help patients regain the strength and train muscles to compensate for the decreased range of motion. It is important that PT be coupled with a daily walking program, as walking at least 1.5 miles a day has been shown to decrease the disability from arthritis.
- Injections - Several types of injections are used to alleviate pain and decreased inflammation in the joint that is caused by arthritis. The injectable options include steroid, hyaluronic acid, and platelet rich plasma.
- Anti-inflammatories - Nonsteroidal anti-inflammatory medications such as Ibuprofen or Aleve can help decrease inflammation and pain caused by knee arthritis. This can be beneficial in addition to physical therapy, so patients can have less pain while regaining their motion and strength. Prescription-strength anti-inflammatory medications are occasionally prescribed if over-the-counter medications are not working.
- Surgery - When patients have pain every day that significantly interferes with their quality of life and have failed more conservative treatments, surgery to replace the arthritic knee should be considered. This is a very effective treatment for alleviating pain and improving range of motion and function.
Knee arthritis causes a deep ache in the knee joint that is often worse at night. Patients also frequently experience a cracking or grinding in the knee with movement that is called crepitus. The pain starts insidiously, which means it usually starts without any trauma or specific event. After taking a detailed history and a physical exam, x-rays will be obtained. This is a diagnosis that is usually made with x-rays, which show narrowing of the space between the bones that make up the knee joint and can show the bone rubbing on bone.
Conservative treatments are always recommended first. When patients have persistent pain/dysfunction that interferes with their quality of life and they have pain every day, surgery is recommended.
The most common risks are stiffness, persistent pain, and weakness. The arthritis will gradually worsen over time. As the pain progresses, range of motion typically gets worse and this leads to limited use and function that can interfere with the ability to walk.