Knee Replacement FAQ
Knee replacement is a routine surgery performed on over 600,000 people worldwide each year. It is becoming more common as our society becomes more active, incurring sports injuries which later develop into osteoarthritis.
Knee replacement in general is a very successful operation and many patients enjoy relief from pain and improved function, compared to their status before surgery. In fact, according to an Arthritis Foundation study, outcomes for total knee replacement generally have 90% to 95% patient satisfaction, and most new joints will last from 10 to 15 years.
What is Knee Replacement?
In knee replacement surgery, the ends of the bones that make up the knee are repaired and are resurfaced with metal and plastic implants. Using special, precision instruments, your surgeon will typically remove the damaged surfaces of all three bones that make up the knee. The replacement surfaces will then be fixed into place.
The surface of the femur is replaced with a rounded metal component that comes very close to matching the curve of your natural bone. The surface of the tibia is replaced with a smooth plastic component. This flat metal component holds a smooth plastic piece made of ultra-high-molecular-weight polyethylene plastic that serves as the cartilage. The undersurface of the kneecap may also be replaced with an implant made of the same polyethylene plastic.
The new joint works the way cartilage works in a healthy knee by preventing the bones of the leg from rubbing together at the joint.
Types of Knee Replacement
Total Knee Replacement
Total knee replacement is the relining of the knee joint with artificial implants. There are three components used in the artificial knee. The femoral (thigh) component is made of metal and covers the end of the thigh bone.
The tibial (shin bone) component, made of metal and plastic, covers the top end of the tibia. The metal forms the base of this component, while the plastic is attached to the top of the metal to serve as a cushion and smooth gliding surface.
The third component, the patella (kneecap), may be all plastic or a combination of metal and plastic.
The new components are stabilized by your ligaments and muscles, just like your natural knee.
Partial Knee Replacement
If X-ray and MRI results show that one side of your knee is damaged, you may be a candidate for a partial knee replacement. Partial knee replacement repairs just the side of the knee joint that is damage instead of the entire joint surface.
Partial knee replacement is not usually considered for active or heavy people because they can put too much stress on the implant. In addition, if two or more compartments of your knee are damaged, your surgeon will probably recommend total knee replacement.
Frequently Asked Questions
How long is too long to wait for total knee replacement?
Early diagnosis and treatment of osteoarthritis are important for your long-term mobility. In fact, having knee replacement surgery earlier in the course of the disease may be linked with better outcomes. If your doctor has recommended that you undergo a knee replacement, don’t delay. Delaying surgery can lower your quality of life, both before and after surgery.
Am I going to have much pain after surgery?
Many patients find that the pain after surgery is tolerable, treatable, and subsides gradually over a few months. Sacred Heart has a variety of options to manage pain and keep patients comfortable after surgery, such as numbing injections, IV pain medication, patient-controlled anesthesia, injections, pain pills and anti-inflammatory medications.
How long will I be in the hospital?
The typical hospital stay is one to three days.
What kind of anesthesia will I have?
There are two common types of anesthesia used during knee replacement surgery: general anesthesia where the patient is put to sleep, and regional anesthesia, where the patient is numbed below the waist, typically with an epidural. Which type of anesthesia you will receive depends on your situation as the patient, as well as your surgeon's and anesthesiologist's recommendations. Please speak with your surgeon or anesthesiologist if you have any concerns regarding the anesthesia that will be used during surgery.
How soon can I return to normal activities after surgery?
Within six weeks after surgery, most patients are able to walk with a cane. You will probably feel well enough to drive a car within seven to eight weeks after surgery.
In most cases, successful joint replacement surgery will relieve your pain and stiffness, and will allow you to resume many of your normal daily activities. But even after you have fully recovered from your surgery, you will still have some restrictions, including refraining from contact sports or activities that put excessive strain on your joints.
Will an implant set off a metal detector?
Since knee implants are made of metal, there is a chance they could set off metal detectors. After your surgery, you will be provided with a special card to keep in your wallet explaining that you have a knee implant.
How long will the implant last?
The life of a knee joint implant is unique to each patient, depending on your physical condition, activity level, and weight, as well as the accuracy of implant placement during surgery. It is useful to keep in mind that prosthetic joints are not as strong or durable as a natural, healthy joint, and there is no guarantee that a prosthetic joint will last the rest of a patient's life. Most replacement joints can be expected to last for 10-15 years.
Is Knee Replacement Right For Me?
Doctors generally try to delay total knee replacement for as long as possible in favor of less invasive treatments. However, for patients with advanced joint disease or injury, knee replacement offers the chance for relief from pain and a return to normal activities.
If you have difficulty walking or performing everyday activities such as getting dressed, it may be time to consider knee replacement surgery.
If you answer yes to any of the questions below, you should speak with your orthopaedic surgeon about knee replacement surgery.
• Does your knee hurt one or more days per week?
• Does the pain interfere with your sleep?
• Is it painful for you to walk more than a block?
• Are pain medications no longer working?
• Is knee pain limiting your participation in activities?
• Has inactivity from knee pain caused you to gain weight?
• Can you limit activities for a few months to recover from surgery?
• Are you willing to commit to work hard during your rehabilitation for a successful recovery?