Total knee replacement

Anatomy

The knee is a hinge joint, meaning it can only bend in one direction. It is where the tibia, the femur, and the patella meet. Like most joints in the body, the knee joint is lined with articular cartilage. The articular cartilage acts as a shock absorber and allows smooth and stable movement. When the articular cartilage wears away, knee replacement can alleviate pain and restore both movement and function.

What is total knee replacement (TKA)?

A total knee arthroplasty (TKA) or knee joint replacement surgery involves replacing the worn-out, diseased knee cartilage with metal and plastic materials designed to restore knee motion and function.

Watch Dr. Michael A. Miranda explain what happens during knee replacement

What happens during the actual surgery for complete knee replacement?

At a high level, a total knee replacement surgery follows these four steps:

1. First, you’ll receive anesthesia—either general (putting you to sleep) or regional (numbing the lower half of your body)—so you’re comfortable and don’t feel any pain during the procedure.
2. The surgeon starts by making an incision to access your knee joint so they can carefully cut and remove the diseased cartilage and bone from the ends of your femur (thigh bone) and tibia (shin bone). The surgeon then caps the cut bone surfaces with metal implants, effectively restoring the shape and dimensions of the knee joint surfaces. Each of the metal implants on the bone ends then mate with and glides on a special, extremely smooth plastic spacer called polyethylene.
3. For many patients, the surgeon will also cut a small portion of the patella and implant a plastic cap.
4. Once everything is confirmed to be securely in place and aligned correctly, the surgeon closes the incision and applies a dressing to protect the wound.

The patient is usually moved to a recovery area after surgery. Physical therapy to restore movement and strength starts immediately, and most patients can begin walking with assistance shortly after surgery. They gradually increase their activity levels as they heal.

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What is life like after having new knee replacement surgery?

Recovery from a total knee replacement usually involves several weeks of home physical therapy followed by four to six weeks of outpatient physical therapy, which strengthens the knee and helps restore movement and range of motion.

Most patients start walking with assistance soon after the surgery and gradually increase their activity levels. While recovery times can vary, many individuals can resume their daily activities within six weeks to three months, experiencing improved mobility and reduced pain.

Ongoing exercises and follow-up appointments with your healthcare team are essential to ensure a smooth and successful recovery.

Typical outcomes of full knee replacement

Total knee replacement surgery is often highly successful. According to the American Academy of Orthopaedic Surgeons (AAOS), studies show that approximately 90–95% of knee implants remain functional and pain-free 10 to 15 years after the procedure.

The National Joint Registry’s research findings show that most patients experience significant improvements in mobility and quality of life after surgery, with 85–90% reporting high satisfaction levels.

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Potential total knee replacement complications

Complications for patients after total knee replacement are relatively rare, occurring in less than 5% of cases, according to the Centers for Disease Control and Prevention (CDC). Problems may include infections, stiffness, mechanical implant issues and blood clots.

Procedures related to surgery for knee replacement

In addition to the standard total knee replacement, there are several specialized procedures—designed to address specific needs and enhance quality of life—such as:

• Partial knee replacement,
• Bilateral knee replacement and
• Knee revision surgery

Partial knee replacement

Your knee has three compartments: the medial (or inside compartment), lateral (outside compartment), and patellofemoral (front compartment).

A partial knee replacement, or unicompartmental knee arthroplasty (UKA), involves fixing only one of the three compartments (leaving the other healthy compartments and ligaments as is). In contrast, a surgeon replaces all three compartments during a total knee replacement. The parts that need substituting determine whether a knee replacement is partial or total.

A surgeon replaces only one damaged joint compartment in a partial knee replacement, leaving healthy compartments and ligaments intact. This option often leads to a quicker recovery, provides a more natural feeling to the knee, maintains more bone and ligaments and preserves more of your natural mobility.

Learn more about partial knee replacements

Bilateral knee replacement

Bilateral knee replacements involve replacing both knee joints simultaneously. This may be a good choice if you have severe arthritis in both knees and want to undergo only one surgery and recovery process. However, it has downsides, including a higher risk of complications after the surgery. You should discuss this option with your surgeon.

Knee revision surgery

Surgeons may recommend knee revisions for patients when their replacements stop functioning correctly. In this procedure, artificial knee joints are repaired or replaced to help improve mobility and reduce pain.

Hear Dr. Spencer Smith talk about helping patients with failed knee replacements

Surgical approaches for complete knee replacement

Multiple approaches for total knee replacement are available, including the medial parapaterllar as well as midvastus and subvastus approaches. Each offers different benefits.

To ensure a successful surgery and smooth recovery, a knee surgeon will choose the best total knee replacement surgery approach for you. They’ll consider your specific situation, needs and other factors (such as your anatomy, activity level and previous knee problems).

Medial parapatellar approach

Historically considered the standard incision for new knee replacement surgery, the medial parapatellar approach involves accessing the knee joint through the inner (medial) side of the kneecap.

• Benefits: The medial parapatellar approach gives knee surgeons a clearer view of the knee, making it easier to insert a new artificial joint accurately into place.
• When It’s Used: This approach is often chosen for patients who need thorough knee joint cleaning or who have more complex knee issues.

Midvastus and subvastus approaches

The midvastus and subvastus approaches to total knee replacement are minimally invasive because of smaller incisions through the quadriceps (thigh) muscle.

Who benefits from knee arthroplasty?

The knee is a hinge joint, meaning it can only bend in one direction. It’s where the tibia, the femur, and the patella meet. Like most of the body’s joints, the knee is lined with articular cartilage. The articular cartilage acts as a shock absorber, allowing smooth and stable movement. When the articular cartilage wears away, knee replacement can alleviate pain and restore movement and function.

If you have severe knee pain and limited movement due to arthritis or joint damage, knee arthroplasty can help you regain your everyday activities and improve your quality of life.

What is knee arthritis?

Arthritis is an indication that you’ve lost or experienced significant damage to your knee’s cartilage. It’s similar to a tire losing its tread.

The severity of arthritis is often determined based on X-rays and is defined by how thin the knee’s cartilage has become. In cases of “bone-on-bone” arthritis, the disease is very serious.

What are non-invasive treatment options?

Chronic knee arthritis can significantly disrupt daily life, making walking and climbing stairs more difficult. Simple tasks—such as getting in and out of cars or rising from chairs—can become painful and exhausting. Conservative treatment includes physical therapy, non-steroidal anti-inflammatories (NSAIDs), Tylenol, and various injections.

The most common injection performed is a corticosteroid, which is a powerful anti-inflammatory. We also offer specialty injections and other advanced therapies to support tissue health and recovery. The effectiveness of each option varies and should be discussed independently with your surgeon.

How do I know if I need a knee replaced?

Deciding whether to undergo knee replacement is a significant step. Although it’s considered a safer orthopedic procedure, total knee replacement is still a major operation, so it’s natural to question whether it’s right for you.

Here are examples of when it might be time to think about having complete knee replacement surgery:

• You’ve exhausted conservative treatment options without satisfactory relief.
• Your pain and loss of knee function make it hard to perform everyday tasks and enjoy activities you love.
• You’re in good overall health and medically fit for surgery—able to tolerate anesthesia and rehabilitation.
• You’re mentally prepared for total knee replacement surgery and motivated to participate in the post-operative recovery process.

If surgery for knee replacement might be right for you, schedule an appointment to discuss your symptoms, medical history, and treatment options with an experienced knee surgeon.

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Advances in surgery for knee replacement

Since the first total knee replacement surgery was performed in 1968, surgery to replace the knee joint completely has continually evolved in its usefulness, effectiveness, and overall success. Recent innovations and improvements in total knee replacement surgery have significantly enhanced patient outcomes and recovery experiences.

Robot-assisted and computer-guided procedures improve the precision of implant placement and alignment, which may impact long-term results and implant survivorship. Additionally, outpatient (or same-day) knee replacement surgeries allow eligible patients to return home the same day, reducing hospital stays and promoting quicker recoveries.

Watch Dr. Thomas L. Bernasek talk about the benefits of outpatient joint surgery

New pain management techniques, including improved anesthesia protocols and targeted pain control strategies, help minimize post-operative discomfort and enable patients to begin physical therapy sooner.

These advancements collectively make knee replacement surgeries safer, more efficient, and more comfortable, allowing patients to regain mobility and quality of life more smoothly.

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Selecting a surgeon for full knee replacement

Identifying the right surgeon for your knee replacement is a crucial step toward a successful surgery and recovery. Research the providers you’re considering and evaluate the following factors to make an informed decision:

• Experience and expertise: Look for a surgeon specializing in knee arthroplasty and inquire about their success rates. Research suggests that patients who select surgeons with joint replacement surgery fellowship training achieve better outcomes than people who pick surgeons without such specialized qualifications. Additionally, those who have the expertise to manage joint replacements that have failed are often more experienced in managing complex issues that may arise.
• Convenient care options: Make it easy on yourself. Choose a knee replacement surgeon who’s part of a robust orthopedic health system (with various locations and comprehensive services). By doing so, scheduling may be more flexible, and getting coordinated care—for everything from imaging to physical therapy and rehabilitation—might be easier, too.
• Patient feedback: Seek referrals from trusted friends and family members, or ask your primary care provider. You can also gauge others’ surgery for knee replacement experience satisfaction with a provider by researching reviews and reading patient testimonials.

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Total knee replacement FAQs

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