A total knee replacement is surgery to replace a damaged knee joint with an artificial one made of metal and plastic. The surgeon removes the worn-out cartilage and bone ends, then attaches the new parts to your thigh bone, shin bone, and kneecap. The goal is to eliminate pain and restore function so you can walk, climb stairs, and do daily activities without the grinding pain of bone rubbing on bone.
What Exactly Happens During the Surgery?
The procedure takes about one to two hours. You will be under general anesthesia, which puts you completely to sleep, or regional anesthesia, which numbs you from the waist down.
The surgeon makes a straight cut down the front of your knee, usually about six to ten inches long. They move your kneecap to the side to reach the joint underneath.
Next, they cut the damaged ends of your femur, which is your thigh bone, and your tibia, which is your shin bone. The cuts are precise. They remove only the damaged bone and cartilage, keeping healthy bone intact.
The artificial parts are then fitted. A metal cap goes on the femur, a metal tray goes on the tibia, and a smooth plastic spacer sits between them to act like cartilage. The back of your kneecap may also get a plastic button if it is worn down.
Finally, the surgeon tests the new joint to make sure it bends and straightens properly. They check that the ligaments are balanced and the knee is stable. Then they close the incision with stitches or staples.
What Are the Artificial Parts Made Of?
The implant materials have been refined over decades. The metal parts are usually a cobalt-chromium alloy or titanium. These metals are strong enough to handle the weight and stress of walking.
The plastic spacer is made of ultra-high-molecular-weight polyethylene. This is a very durable plastic that provides a smooth gliding surface. Some implants have a plastic that is cross-linked to make it even more resistant to wear.
Your surgeon may use cement to fix the parts to your bone, or they may use a press-fit implant that has a rough surface. Bone grows into that rough surface over time. Both methods are common, and the choice depends on your bone quality and your surgeon’s preference.
Some newer implants use ceramic parts. These are harder and may last longer, but they are not right for everyone. Your surgeon will discuss the best option for your specific situation.
How Do They Do a Total Knee Replacement With Robotics?
Robotic-assisted knee replacement is becoming more common. This does not mean a robot performs the surgery. Your surgeon is still in full control at all times.
Before surgery, you get a CT scan of your knee. The computer uses that scan to create a 3D model of your joint. During surgery, the robotic arm helps the surgeon make cuts with extreme precision.
The system tracks your knee’s position in real time, and the surgeon guides the robotic arm to remove bone exactly where planned. It is like a highly accurate measuring tool that helps avoid small errors.
Some research suggests robotic-assisted surgery may improve the alignment of the new joint. Whether that translates into better long-term outcomes is still being studied. The evidence does not yet clearly show that robotic surgery leads to a longer-lasting implant or better pain relief than a skilled surgeon using traditional techniques.
How Long Does Recovery Take?
Most people stay in the hospital for one to three days after surgery. Many patients go home the same day or the next day, depending on their health and home support.
You will start moving your knee within hours of surgery. A physical therapist will help you get out of bed and walk with a walker. This early movement is critical. It helps prevent blood clots and keeps your new joint from getting stiff.
At home, you will continue physical therapy for several weeks. Most people use a walker for the first two to four weeks, then move to a cane. You can usually drive again after four to six weeks, but only when you can press the brake safely and you are no longer taking narcotic pain medication.
Full recovery takes longer than most people expect. At six weeks, you may feel significantly better. At three months, you might walk without a limp. Complete recovery, where the knee feels stable and strong, often takes six months to a full year.
What Are the Risks and Complications?
Total knee replacement is generally safe, but it is major surgery. Complications are not common, but they do happen.
Blood clots in the leg are a known risk. Your surgeon will give you blood thinners and compression devices to reduce this risk. Moving early also helps prevent clots.
Infection is the most serious concern. The hospital gives you antibiotics before surgery to lower the risk. If an infection develops deep in the joint, it may require another surgery to clean it out or remove the implant.
Other possible issues include stiffness, nerve damage, and bleeding. Some patients report that their knee makes a clicking or clunking sound. This is often normal and not a cause for concern.
The implant itself can wear out over time. Modern implants typically last 15 to 20 years or more. Younger, more active patients may wear out their implant sooner and need a second surgery.
Who Is a Good Candidate for This Surgery?
Total knee replacement is not the first treatment option. Doctors try conservative measures first. These include physical therapy, weight loss, activity modification, and pain medications.
Injections of steroids or lubricants are also options. These can provide temporary relief but do not fix the underlying damage.
Surgery is usually considered when these treatments no longer control the pain. Candidates typically have advanced arthritis that shows up clearly on X-rays. They have significant cartilage loss, often with bone touching bone.
Your overall health matters. Uncontrolled high blood pressure, severe heart disease, or active infections can make surgery riskier. Smoking slows healing and increases complication rates. Many surgeons require patients to quit smoking before surgery.
Being overweight increases the risk of complications but does not automatically disqualify you. Many surgeons will work with you to optimize your health before scheduling the procedure.
What Results Can You Realistically Expect?
Total knee replacement is one of the most successful surgeries in modern medicine. More than 90 percent of patients report significant pain relief and improved function.
However, the new knee is not a normal knee. You will not have the same range of motion or sensation as a healthy young knee. You may feel some stiffness, especially after sitting for long periods. Some patients feel a mild ache that comes and goes.
Most people can walk, swim, golf, and dance after recovery. High-impact activities like running and jumping are not recommended because they can wear out the implant faster. Low-impact activities are encouraged for the rest of your life.
The key to a good outcome is your participation in rehabilitation. Physical therapy is not optional. The strength you build in the months after surgery determines how well your knee functions for years to come.
How Do You Prepare for the Surgery?
Preparation starts weeks before your operation. Your surgical team will run blood tests and may ask you to see your primary care doctor for a full check-up.
You may be asked to stop certain medications. Blood thinners, anti-inflammatory drugs, and some diabetes medications can increase bleeding risk. Your surgeon will tell you exactly which medications to stop and when.
Set up your home before surgery. Put essential items at waist level so you do not have to bend or reach. Arrange for help with cooking, cleaning, and driving for the first few weeks.
Consider doing pre-habilitation. Strengthening your leg muscles before surgery can speed up your recovery. Simple exercises like straight leg raises and quad sets can make a difference.
Have realistic expectations. Talk openly with your surgeon about what you want to achieve. Ask about pain management, recovery timelines, and what limitations you may have after the surgery.
Frequently Asked Questions
How long does a total knee replacement last?
Modern implants typically last 15 to 20 years or more. The exact lifespan depends on your age, weight, activity level, and how well you follow your recovery plan.
Will I be awake during the surgery?
You will be under anesthesia, so you will not feel or remember anything. You may have general anesthesia for full sleep or regional anesthesia that numbs you from the waist down with sedation to keep you relaxed.
When can I walk after a total knee replacement?
You will stand and walk with a walker within a few hours after surgery. Most people use a walker for two to four weeks before moving to a cane.
How painful is recovery from knee replacement?
You will have significant pain for the first few days, but it is managed with medications. The pain steadily improves, and most patients say the surgical pain is far less than the arthritis pain they lived with before.
