Knee Replacement

About Total Knee Replacement Surgery 

USNWR Knee Replacement badge

Total knee replacement surgery involves capping off the ends of the thigh bone (femur) and shin bone (tibia) with metal and plastic. In some instances, the kneecap (patella) may be also be covered with a plastic cap or button. These new, artificial knee joint components are usually attached using cement.

Patients sometimes ask about different approaches to surgery they have heard or read about, including robotic-assisted or computer-navigated procedures, or custom cutting blocks. While robotic-assisted procedures are the right option for some of the patients we treat, they represent a very small number of the procedures we perform. Your surgeon will discuss the best options for your specific situation. 

Preparing and Recovering from your Knee Replacement

About Partial Knee Replacement

In addition to total knee replacement, a partial knee replacement procedure may be an option for some patients. When the ligaments of the knee are intact and the symptoms and pain are isolated in the medial compartment (the inside of the knee), a partial replacement can provide good relief for symptoms. You and your surgeon can determine if this procedure, called a uni-compartmental or UNI replacement, is an option for you.

See the section below for answers to frequently asked questions about total knee replacement.

How the Knee Works and Causes of Knee Deterioration

Inside a healthy knee joint, thick cushioning (called hyaline cartilage) covers and protects the ends of your bones. Another type of cartilage called the meniscus acts like a shock absorber between the bones, cushioning the surfaces of the knee joint and the ends of the bones, and keeping the joint stable by evenly spreading out the weight it bears. 

In addition to normal wear and tear which leads to degenerative arthritis, a number of other conditions can cause the knee cartilage to deteriorate or break down, including:

  • Inflammatory conditions such as rheumatoid arthritis, gout or osteonecrosis 
  • An injury or trauma to the meniscus or other ligaments
  • Obesity-related wear and tear

Symptoms of Knee Deterioration

The first symptom that knee cartilage is deteriorating is pain that occurs when weight bearing and walking. Patients in their fifties or older who are limited in how much they can walk, despite trying the non-surgical options described below, may be good candidates for knee replacement surgery.

Knee replacement is not for everyone experiencing knee problems. Patients whose pain only occurs when going up and down stairs, those who can walk on level ground without much difficulty, and those who are primarily troubled by a restricted range of motion with little or no pain are not good candidates for knee replacement. Losing excess weight, regular exercise and physical therapy (discussed below) may help relieve these symptoms.

Arriving at a Diagnosis

If you find yourself with “achy knees” or pain when walking, losing weight and exercising are the first strategies to try before exploring knee replacement surgery.

If those strategies (discussed below) do not help, the next step is to see your primary care physician for X-rays of the knee, including standing and weight-bearing X-rays. Additional tests like MRI or CT are not necessary for a routine evaluation of arthritis in the knee. They may be useful if X-rays show little or no arthritis but you are experiencing sharp pain and/or clicking or popping sensations when twisting, or if your knee is unstable or giving way, even if there is no pain.

If you and your doctor determine that a consultation with our orthopaedic surgery team is called for, your initial appointment will include reviewing your overall health history as well as the history of your knee symptoms and your previous X-rays. We will conduct a physical exam of the knee including gait testing and ligament and strength testing.  In rare instances, we may also perform blood tests or other special imaging.

For patients who have not made efforts to relieve symptoms through knee exercise and weight loss, we offer specific recommendations and counseling for those strategies. In some cases, we may also discuss the risks and benefits of cortisone injections. When these non-surgical options have failed to relieve symptoms, the risks and benefits of knee replacement or partial knee replacement will be reviewed.

Options to Try Before Knee Surgery

We recommend that every patient begin with a program of diet/weight loss and exercise to treat their knee arthritis before considering knee replacement. 

Many Americans with and without knee arthritis are above their ideal body weight. The mechanical function of the knee (which must lift the body with each step) are such that losing even a few pounds can bring significant relief from symptoms. In fact, parts of the knee take on five times the body’s weight with a single stair step.

Of course, there is a “catch 22” when it comes to knee arthritis and obesity. When the knee hurts, a person becomes less active, thus tending to gain weight even when maintaining the same diet. With inactivity and excess weight, the knee hurts more, and the cycle continues.

To break the cycle, we recommend “closed chain” exercises such as a leg press or an exercise bike set at a comfortable seat level and low resistance. In most cases, people see a return of muscle function and coordination as well as relief of symptoms. In addition to the meniscus, the quadriceps and hamstrings also act as shock absorbers for the knee, so strengthening these muscles is an important first step in treating knee pain.  

For patients above their recommended body weight (usually a body mass index (BMI) of 35 or lower), we recommend a program of eliminating simple carbohydrates (such as starches like potatoes, rice, bread and noodles), and simple sugars (such as desserts or sweets, sugared soda and alcohol), along with adequate hydration (water consumption) and supplementing fiber intake.

Wondering about the ideal weight for your height? Check out the BMI calculator on the Centers for Disease Control (CDC) website.

In addition to recommending weight loss and exercise, we often suggest that patients use non-steroidal medications such as ibuprofen or acetaminophen to reduce swelling and pain. We also commonly recommend trying injections of steroids like cortisone as well before considering knee replacement.  

See the section below for answers to frequently asked questions about total knee replacement.

Why Choose Michigan Medicine for Your Knee Replacement?

Michigan Medicine is ranked among the top hospitals in the nation by U.S. News and World Report

Our Department of Orthopaedic Surgery has been a high-volume provider and a pioneer in surgical care, education and research since 1930. We specialize in knee replacement procedures that are less invasive and require less recovery time.

We are at the forefront of developing and using new joint replacement implants as well as collecting patient reported outcomes (PROS) and following our patients’ clinical outcomes as part of a statewide registry called the Michigan Arthroplasty Collaborative Quality Initiative (MARCQI)

In addition, as a top academic institution, we offer access to the latest clinical trials in orthopaedic surgery, and we encourage our patients to learn about and participate in trials when appropriate.

Other Resources

Knee Replacement Care Pathway After Discharge

Knee Replacement Education Booklet 

Contact Us / Make an Appointment

Determining whether and where to have joint surgery are important decisions. Because we are highly experienced in total knee replacement, we can help you explore your options.

Call 734-936-5780 to speak with a representative in our Orthopaedic Surgery Call Center to learn more or make an appointment for a consultation.

Frequently Asked Questions About Knee Replacement Surgery

How long does surgery take? 

While the actual replacement procedure might take only an hour, there are numerous steps before and after surgery that can make the entire process take several hours. We tell patients it is similar to flying from one airport to another. While an actual flight might take only about an hour, you should still plan on spending plenty of time at the airport before departing and after arriving.

What are the possible risks and side effects of knee replacement surgery?

As with any surgery, knee replacement comes with a low risk of certain medical complications:

  • Less than one percent of patients undergoing any type of surgery will have some cardiovascular event such as a stroke or heart attack brought on by the stress of the event.
  • About 0.5 percent of knee replacement patients will develop an infection.

A more common outcome from knee replacement is ongoing discomfort significant enough to make the patient feel the surgery was not successful and to regret having the procedure. This “buyer’s remorse” impacts 15 to 20 percent of patients, who continue to experience pain, clicking and/or stiffness, sometimes feeling that they traded one type of pain for another. 

Because some patients regret undergoing the procedure, patients should not make the decision to replace a knee without careful consideration.

How long does it take to recover from surgery? 

After knee surgery, the knee is swollen and difficult to bend, and the main challenge is finding the right balance between returning to activity and keeping swelling under control. Slowly building activity levels and elevating and icing the knee to reduce swelling are both essential to recovery.

While every patient’s recovery time is different, about four weeks after surgery, most people are up and walking without a cane or walker and can bend the knee to or beyond 90 degrees, although they may still experience some pain or stiffness.

In general, most patients (80 to 85 percent) are happy with their decision to pursue knee replacement and feel that their knee functions better than before the procedure. These patients are able to return to walking, hiking, tennis, golf, biking and other light recreation. We discourage high impact activities such as basketball and running following knee replacement.