Charles Hope, MD: HIP Replacement
TOTAL 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 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.
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 in harmony. But disease or injury can disrupt this harmony, resulting in pain, muscle weakness, and reduced function.
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.
Osteoarthritis. This is an age-related “wear and tear” type of arthritis. It 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.
Rheumatoid 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.”
Post-traumatic 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.
Osteoarthritis often results in bone rubbing on bone. Bone spurs are a common feature of this form of arthritis.
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.
DECIDING TO HAVE KNEE REPLACEMENT SURGERY
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. 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.
With appropriate activity modification, knee replacements can last for many years.
PREPARING FOR SURGERY
If you decide to have total knee replacement surgery, Dr. Sutherland may ask you to schedule a complete physical examination with your family physician several weeks before the operation. This is needed to make sure you are healthy enough to have the surgery and complete the recovery process. Many patients with chronic medical conditions, like heart disease, may also be evaluated by a specialist, such as a cardiologist, before the surgery.
Tell your orthopaedic surgeon about the medications you are taking. He or she will tell you which medications you should stop taking and which you should continue to take before surgery.
Although the incidence of infection after knee replacement is very low, an infection can occur if bacteria enter your bloodstream. To reduce the risk of infection, major dental procedures (such as tooth extractions and periodontal work) should be completed before your total knee replacement surgery.
People with a history of recent or frequent urinary infections should have a urological evaluation before surgery. Older men with prostate disease should consider completing required treatment before undertaking knee replacement surgery.
Although you will be able to walk on crutches or a walker soon after surgery, you will need help for several weeks with such tasks as cooking, shopping, bathing, and doing laundry.
If you live alone, your surgeon’s office, a social worker, or a discharge planner at the hospital can help you make advance arrangements to have someone assist you at home. They also can help you arrange for a short stay in an extended care facility during your recovery if this option works best for you.
Several modifications can make your home easier to navigate during your recovery. The following items may help with daily activities:
Safety bars or a secure handrail in your shower or bath
Secure handrails along your stairways
A stable chair for your early recovery with a firm seat cushion (and a height of 18 to 20 inches), a firm back, two arms, and a footstool for intermittent leg elevation
A toilet seat riser with arms, if you have a low toilet
A stable shower bench or chair for bathing
Removing all loose carpets and cords
A temporary living space on the same floor because walking up or downstairs will be more difficult during your early recovery
Dr. Sutherland performs both traditional total knee replacement as well as patient-specific total knee replacement. The former involves obtaining an MRI of your entire leg that includes your hip knee and ankle. From this, a computer-generated model is constructed that is an exact replica of your knee. From the MRI the sizes and alignment of your knee can be planned prior to surgery, and in fact, the computer model can be manipulated prior to your surgery for a fit that more closely resembles your normal anatomy.
YOUR HOSPITAL STAY
You will most likely stay in the hospital between 2-5 days.
After surgery, you will feel some pain, but your surgeon and nurses will provide medication. Dr. Sutherland has adopted a multimodal approach to pain control. This will include preoperative oral medications and nerve blocks, intraoperative joint blocks and postoperative pain control that include cryotherapy, swelling control and well as oral and intravenous pain controls that attack pain in multiple forms.
Blood Clot Prevention
Dr. Sutherland uses many different medications and mechanical devices to prevent blood clots. No treatment is perfect and plans for your blood clot prevention will be agreed upon at your pre-operative visit.
A continuous passive motion machine can help prevent postoperative knee stiffness in the early postoperative period.
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.
To restore movement in your knee and leg, your surgeon may use a knee support that slowly moves your knee while you are in bed. The device, called a continuous passive motion (CPM) exercise machine, decreases leg swelling by elevating your leg and improves your blood circulation by moving the muscles of your leg.
It is common for patients to have shallow breathing in the early postoperative period. This is usually due to the effects of anesthesia, pain medications, and increased time spent in bed. This shallow breathing can lead to a partial collapse of the lungs (termed “atelectasis”) which can make patients susceptible to pneumonia. To help prevent this, it is important to take frequent deep breaths. Your nurse may provide a simple breathing apparatus called a spirometer to encourage you to take deep breaths.
YOUR RECOVERY AT HOME
You will have staples running along your wound or a suture beneath your skin on the front of your knee. The stitches or staples will be removed 2l weeks after surgery. A suture beneath your skin will not require removal.
Avoid soaking the wound in water until it has thoroughly sealed and dried. You may continue to bandage the wound to prevent irritation from clothing or support stockings.
Some loss of appetite is common for several weeks after surgery. A balanced diet, often with an iron supplement, is important to help your wound heal and to restore muscle strength.
Exercise is a critical component of home care, particularly during the first few weeks after surgery. You should be able to resume most normal activities of daily living within 3 to 6 weeks following surgery. Some pain with activity and at night is common for several weeks after surgery.
Your activity program should include:
A graduated walking program to slowly increase your mobility, initially in your home and later outside
Resuming other normal household activities, such as sitting, standing, and climbing stairs
Specific exercises several times a day to restore movement and strengthen your knee. You probably will be able to perform the exercises without help, but you may have a physical therapist help you at home or in a therapy center the first few weeks after surgery.
You will most likely be able to resume driving when your knee bends enough that you can enter and sit comfortably in your car, and when your muscle control provides adequate reaction time for braking and acceleration. Most people resume driving approximately 4 to 6 weeks after surgery.