Total and Partial Knee Replacement

If your knee is severely damaged by arthritis or injury, it may be hard for you to perform simple activities, such as walking or climbing stairs. You may even begin to feel pain while you are sitting or lying down. If nonsurgical treatments like medications and using walking supports are no longer helpful, you may want to consider total knee replacement surgery. Joint replacement surgery is a safe and effective procedure to relieve pain, correct leg deformity, and help you resume normal activities. Knee replacement surgery was first performed in 1968. Since then, improvements in surgical materials and implants and techniques have greatly increased its effectiveness. Total knee replacements are one of the most successful procedures in all of medicine. According to the Agency for Healthcare Research and Quality, more than 600,000 knee replacements are performed each year in the United States. Whether you have just begun exploring treatment options or have already decided to have total knee replacement surgery, this article will help you understand more about this valuable procedure.

Anatomy of the Knee

Healthy knee without Injury

A Health Knee – Detailed

The knee is the largest joint in the body and having healthy knees is required to perform most everyday activities. The knee is made up of the lower end of the thighbone (femur), the upper end of the shinbone (tibia), and the kneecap (patella). The ends of these three bones where they touch are covered with articular cartilage, a smooth substance that protects the bones and enables them to move easily. The menisci are located between the femur and tibia. These C-shaped wedges act as “shock absorbers” that cushion the joint. Large ligaments hold the femur and tibia together and provide stability. The long thigh muscles give the knee strength. All remaining surfaces of the knee are covered by a thin lining called the synovial membrane. This membrane releases a fluid that lubricates the cartilage, reducing friction to nearly zero in a healthy knee. Normally, all of these components work together. But disease or injury can disrupt the normal functioning of the knee,, resulting in pain, muscle weakness, and reduced function.

Causes of Knee Pain

The most common cause of chronic knee pain and disability is arthritis. Although there are many types of arthritis, most knee pain is caused by just three types: osteoarthritis, rheumatoid arthritis, and post-traumatic arthritis.

This is an age-related “wear and tear” type of arthritis. Osteoarthritis usually occurs in people 50 years of age and older, but may occur in      younger people, too. The cartilage that cushions the bones of the knee softens and wears away. The bones then rub against one another, causing knee pain and stiffness. Osteoarthritis of the knee often results in bone rubbing on bone. Bone spurs are a common feature of this form of arthritis.

This is a disease in which the synovial membrane that surrounds the joint becomes inflamed and thickened. This chronic inflammation can damage the cartilage and eventually cause cartilage loss, pain, and stiffness. Rheumatoid arthritis is the most common form of a group of disorders termed “inflammatory arthritis.”

This can follow a serious knee injury. Fractures of the bones surrounding the knee or tears of the knee ligaments may damage the articular cartilage over time, causing knee pain and limiting knee function.

  • Injury or Accident.

Many of the knee cases I see are related to injury caused from accidents or repetitive use, often times associated with sports or workplace activities.

Knee Replacement Surgery – Total and Partial Knee Replacement

Procedure

Knee replacement surgery takes approximately 1 to 2 hours. Damaged cartilage and bone are removed and then the new metal and plastic implants are positioned to restore the alignment and function of your knee.

Physical Therapy after a Total and Partial Knee Replacement

Most patients begin exercising their knee the day after surgery. A physical therapist will teach you specific exercises to strengthen your leg and restore knee movement to allow walking and other normal daily activities soon after your surgery. Did you know that more than 90% of modern total knee replacements are still functioning well 15 years after the surgery. Let’s take a look at Total Knee Replacement and Partial Knee Replacement in more detail:

Total Knee Replacement

A knee replacement (also called knee arthroplasty) might be more accurately termed a knee “resurfacing” because only the surface of the bones are actually replaced. There are four basic steps to a knee replacement procedure.

  • Prepare the bone
    • The damaged cartilage surfaces at the ends of the femur and tibia are removed along with a small amount of underlying bone.
  • Position the metal implants.
    • The removed cartilage and bone is replaced with metal components that recreate the surface of the joint.
    • These metal parts may be cemented or “press-fit” into the bone.
  • Resurface the patella.
    • The undersurface of the patella (kneecap) is cut and resurfaced with a plastic button.
    • Some surgeons do not resurface the patella, depending upon the case.
  • Insert a spacer.
    • A medical-grade plastic spacer is inserted between the metal components to create a smooth gliding surface.

Partial Knee Replacement

Technological advances have allowed more patients knee arthritis or in some cases injury to benefit from partial knee replacement. This is especially the case when there is only one or two compartments of the knee that has been impacted and there is still good range of motion in the knee. This can happen from disease such as arthritis or repetitive injury due to sports or athletic activity and/or work-related duties.

The benefit of having a partial replacement is that only the one problem area is resurfaced so that healthy tissue, nerves and bone are preserved. This also usually results in the implant being smaller. Additionally, there is some indication that leaving the nerve pathways intact may improve the information to the brain. As a result, some  patients report partial knee replacements feeling like their normal knees.

Partial replacements are becoming more attractive to patients for some the following reasons:

  • Higher patient satisfaction
  • Preserving more normal knee motion
  • Less blood loss during surgery
  • Faster recovery time
  • Small incision
  • Increased range of motion

When the knee is only minimally impacted by injury or disease then the partial knee replacement might be a great option vs. a total knee replacement.

Every patient is unique, so whether the total or partial knee replacement is best for you will be determined after a careful examination and diagnosis. There is some indication that partial knee replacements can fail more often than total knee replacements, so it is important that you work with a surgeon that is experienced in both making an accurate and detailed diagnosis as well performing having regularly performed partial knee replacements.

When Surgery Is Recommended?

There are instances when I would recommend knee replacement surgery. People who benefit from total or partial knee replacement often have:

  • Severe knee pain or stiffness that limits your everyday activities, including walking, climbing stairs, and getting in and out of chairs. You may find it hard to walk more than a few blocks without significant pain and you may need to use a cane or walker
  • Moderate or severe knee pain while resting, either day or night
  • Chronic knee inflammation and swelling that does not improve with rest or medications
  • Knee deformity — a bowing in or out of your knee
  • Failure to substantially improve with other treatments such as anti-inflammatory medications, cortisone injections, lubricating injections, physical therapy, or other surgeries

Candidates for Surgery

There are no absolute age or weight restrictions for total knee replacement surgery. Recommendations for surgery are based on a patient’s pain and disability, not age. Most patients who undergo total knee replacement are age 50 to 80, but I evaluate patients individually. Total and partial knee replacements have been performed successfully at all ages, from the young teenagers with juvenile arthritis to the elderly patients with degenerative arthritis.

Orthopedic Evaluation

An important part of an accurate diagnosis and treatment plan is a physical evaluation. While each evaluation is different as it depends on the specific issues and needs of my patients, it typically consists of several components:

  • A medical history

    • Gathering information about your general health and determining the extent of your knee pain and your ability to function
  • A physical examination

    • This will assess knee motion, stability, strength, and overall leg alignment
  • X-rays

    • These images help to determine the extent of damage and deformity in your knee and are used as an integral part of determine the best course of treatment for you
  • Other tests

    • Occasionally blood tests, or advanced imaging such as a magnetic resonance imaging (MRI) scan, may be needed to determine the condition of the bone and soft tissues of your knee

I review the results of your evaluation with you and discuss whether total knee replacement is the best method to relieve your pain and improve your function. Other treatment options — including medications, injections, physical therapy, or other types of surgery may be the best course of action, but again this depends on the condition of your knee and the desired outcome after treatment.

For patients who are candidates for total or partial knee replacement, I choose the implant that is best suited to each person’s individual anatomy, medical and lifestyle needs.

Deciding to Have Total or Partial Knee Replacement Surgery – Realistic Expectations

An important factor in deciding whether to have total knee replacement surgery is understanding what the procedure can and cannot do. More than 90% of people who have total knee replacement surgery experience a dramatic reduction of knee pain and a significant improvement in the ability to perform common activities of daily living.

Having performed 1000’s of joint replacements, we are well qualified to help you with determining if you need joint replacement and if you are best served with a total or partial knee replacement.

We are always available to answer any of your questions and concerns.

Call us at 580-353-8600 to schedule an appointment.

904 SW 38th Street, Lawton, OK, 73505 Directions

 

Adapted from AAOS