Knee Replacement

With advanced degenerative wear and tear arthritis the knee joint can deteriorate and begin to cause daily constant pain. Knee arthritis can develop from osteoarthritis and post traumatic arthritis. Common activities such as walking or climbing stairs. You can even develop pain while at rest. When nonsurgical treatments are no longer helping to manage the pain then consultation with a surgeon takes place to consider total knee replacement surgery.

Knee replacement surgery first began in 1968 and since that time improvements in material and techniques has greatly advanced the success rate and survivorship leading to increased effectiveness. The total knee replacement is one of the most successful procedures in all of medicine.

Knee Anatomy

The knee is the largest joint in the body and is primarily a hinge type joint. The knee is comprised of the lower end of the femur (thighbone) and the upper end of the tibia (shinbone), and the patella (kneecap). The end of the bones are covered in articular cartilage, a smooth surface enabling the ends to move easily within the joint.

The menisci are two C-shaped cartilage wedges (medial meniscus & lateral meniscus) that act as “shock absorbers” to cushion the joint.

Ligaments hold the femur and tibia together to provide stability in all 3 planes. The cruciate ligaments are in the centre of the knee and provide forward and backward stability while the collateral ligaments are on either side of the joint providing bending stability.

The knee is divided into three major compartments:

Medial compartment (the inside part of the knee)
Lateral compartment (the outside part of the knee)
Patellofemoral compartment (the front of the knee between the kneecap and thighbone)

When is knee replacement surgery recommended?

There are several indications why your surgeon may recommend knee replacement surgery. People who benefit from knee replacement often have:

severe knee pain or stiffness that limits everyday activities, including walking, climbing stairs, and getting in and out of chairs
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 the knee
failure to substantially improve with other treatments such as anti-inflammatory medications, cortisone
injections, lubricating injections, biologic injections, physical therapy, or other surgeries

What is Unicompartmental (Partial) Knee Replacement?

Advanced osteoarthritis that is limited to a single compartment may be treated with a unicompartmental knee arthroplasty (UKA). During this procedure, the damaged compartment, most often the medial compartment is replaced with metal and plastic components. The healthy cartilage and bone, as well as ligaments, are preserved.

Advantages and Disadvantages of Unicompartmental Knee Replacement

Multiple studies show that most patients who are appropriate candidates for unicompartmental knee replacement have good results with this procedure.

The advantages of partial knee replacement over total knee replacement include quicker recovery, less pain after surgery, less blood loss, and lower risk of infection and blood clots.

Also, because the bone, cartilage, and ligaments in the healthy parts of the knee are preserved, many patients report that a unicompartmental knee replacement feels more natural than a total knee replacement. A unicompartmental knee may also bend better.

Disadvantages of unicompartmental knee replacement compared with total knee replacement is the potential need for more surgery. For example, a total knee replacement may be necessary in the future if arthritis develops in the parts of the knee that have not been replaced.

What is total knee arthroplasty (TKA)?

During total knee arthroplasty surgery, the orthopaedic surgeon will remove the damaged cartilage and bone from both the lateral and medial compartments, and then position the new metal and plastic implants to restore the alignment and function of your knee. The patella is resurfaced only if it demonstrates severe wear.

Most often the femoral and tibial components are cemented into the bone ends and a high polymer plastic spacer is inserted onto the tibial baseplate to allow for a smooth gliding surface.

In younger patients with good bone stock the femoral and tibial components are “press fit” into the bone and bone ingrowth occurs to secure the prosthesis (uncemented).

Most 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. But total knee replacement will not allow you to do more than you could before you developed arthritis.

With normal use and activity, every knee replacement implant begins to wear in its plastic spacer. Excessive activity or weight may speed up this normal wear and may cause the knee replacement to loosen and become painful. Therefore, most surgeons advise against high-impact activities such as running, jogging, jumping, or other high- impact sports for the rest of your life after surgery.

Realistic activities following total knee replacement include unlimited walking, swimming, golf, driving, light hiking, biking, ballroom dancing, and other low-impact sports.

Knee Replacement