Knee replacement, Knee arthroplasty

Overview

Knee replacement surgery is a procedure aimed at replacing damaged or deteriorated components of a knee joint that has suffered injury or wear-and-tear. This surgical intervention is primarily undertaken to alleviate pain and enhance the functionality of the knee. During the surgery, the surgeon replaces compromised bone and cartilage with prosthetic components typically crafted from a combination of metal and plastic materials.

The decision regarding whether a knee replacement is suitable for an individual is determined through a comprehensive evaluation by a surgeon. This evaluation includes an assessment of the knee’s range of motion, stability, and strength. Additionally, X-ray imaging is utilized to visualize and assess the extent of damage within the knee joint.

The choice of the specific artificial joints and surgical techniques employed in the procedure is contingent upon various factors, including the patient’s age, body weight, activity level, the unique size and shape of their knee, and their overall health status.

Types of operation

The healthcare provider will advise either a full or partial knee replacement:

• Total knee replacement: The most common kind of knee replacement is a total knee replacement. The doctor performing the surgery will replace the knee’s medial (inside), lateral (outside), and patellofemoral (under your kneecap) joints.
• Partial knee replacement: In most cases, if only one or two sections of the knee joint are damaged, the surgeon will merely replace portion of them. Younger persons who have undergone trauma or injury are more likely to require partial knee replacements.

Reason for undergoing the procedure

The primary indication for knee replacement surgery is typically the alleviation of pain caused by arthritis, which often results in difficulties with activities such as walking, stair-climbing, and rising from chairs. When only a specific portion of the knee is affected, surgeons can target the replacement accordingly. However, if the entire joint requires intervention, the ends of the thighbone and shinbone undergo reshaping, facilitating complete joint resurfacing. These bones possess a durable outer structure with a softer core into which the artificial components are seamlessly inserted. In cases where the knee’s ligaments lack the necessary strength to maintain joint stability, the surgeon may choose implants that can be securely connected to prevent dislocation.

Risk

Patients who have undergone knee replacement surgery may still experience persistent knee pain, and this can be attributed to several risk factors:

• Blood clots: To reduce this risk, surgeons frequently advise taking blood-thinning medications. Legs are the most typical site for blood clots. Blood clots at the knees are the commonly affected. However, they have the potential to go to the lungs and might be life-threatening.
• Nerve damage: The location where the implant is inserted may suffer from nerve damage. Numbness, weakness, and discomfort can be brought on by nerve injury.
• Infection: Both the incision site and deeper tissue are susceptible to infection. Sometimes, treating an infection requires surgery.
• Medical condition: It is essential to go over the medical history with the surgeon because certain medical issues could make recovering from a knee replacement more difficult. It’s crucial to let the surgeon know about any current medical conditions, including diabetes, lupus, hemophilia, and other autoimmune diseases.

While knee replacement implants are typically durable, over time, they may experience wear and loosening. In such cases, a subsequent surgical procedure might be necessary to address and rectify the damaged or loosened components.

Procedure

Knee arthroplasty is a safe and effective procedure that can lead to improved mobility and a reduction in chronic pain. Following knee replacement surgery, most patients report experiencing less pain, an enhanced quality of life, and increased mobility and functionality in their knee.

Before the procedure

Getting ready for surgery involves several important steps to ensure your safety and a successful procedure.

• Health assessment: Your healthcare provider and surgeon will conduct a thorough physical examination to confirm that you are in good health and suitable for the surgery.
• Medical tests: You will likely undergo various tests, including:
  • Blood tests: These are performed to check the health of your blood.
  • Electrocardiogram (ECG): This test is done to assess the functioning of your heart.
  • Dental exam: A dental examination is conducted to minimize the risk of infection after the surgery.
  • Imaging: Depending on the type of surgery, you may need X-rays, magnetic resonance imaging (MRI), or a computed tomography (CT) scan.
• Medication review: It’s important to inform your healthcare team about all the medications and over-the-counter supplements you are taking. You may need to discontinue some of these medications or supplements before your surgery.
• Fasting instructions: Your surgeon will provide clear guidelines on when you should stop eating and drinking. Typically, you will need to abstain from food and liquids for a period of 12 hours before your surgery.

By following these steps and maintaining open communication with your healthcare providers, you will be well-prepared for your upcoming surgery, ensuring a safer and more successful outcome.

During the procedure

On the day of your surgery, you will receive anesthesia to ensure you are pain-free during the procedure. An anesthesiologist will administer either:

• General anesthesia, which will induce a state of unconsciousness for the entirety of the surgery.
• Regional anesthesia, which will numb the lower part of your body, typically from the waist down.

During a knee replacement surgery, your surgeon will perform the following steps:

• Excise damaged cartilage and bone.
• Implant a prosthetic knee joint.
• Insert a plastic spacer designed to replicate the natural cushioning of cartilage.
• If necessary, reshape the patella (kneecap) to accommodate the new prosthetic knee joint.

After the procedure

Following surgery, you will be transferred to a post-operative recovery area, where a dedicated surgical team will closely monitor your condition for several hours to ensure a smooth awakening from anesthesia and to keep a close watch on your vital signs and pain management. While some individuals undergoing knee replacement surgery may be discharged on the same day, others may require an overnight hospital stay, with your surgeon making the determination of when it is safe for you to be discharged home.

Outcome

Recovery from knee replacement surgery typically takes about a year for full rehabilitation. However, you can usually resume most of your usual activities within six weeks post-surgery. Your specific recovery timeline is influenced by factors such as your pre-surgery activity level, age, and overall health. Your surgeon will provide a personalized recovery plan, but here are key steps to follow:

• Manage pain and swelling: Apply ice to your knee for 20-minute sessions several times a day to alleviate pain and reduce swelling.
• Elevate your knee: Keep your knee elevated above heart level when possible. Use cushions or pillows while lying down, or place it on a footstool while sitting in a chair.
• Incision care: Follow your surgeon’s instructions for cleaning and covering your incision. Ask about changing dressings and when it’s safe to shower or bathe.
• Home exercises: Start prescribed exercises early after surgery to strengthen knee muscles and prevent stiffness. Perform them as instructed by your surgeon to aid in recovery and restore joint function.
• Physical therapy: Work with a physical therapist for several months post-surgery. They will help you safely regain mobility, including knee bending and walking.
• Pain management: Expect pain in the initial weeks after surgery. Your surgeon will recommend a combination of prescription pain medication, over-the-counter NSAIDs (if safe for you), and acetaminophen to manage pain. Follow the dosage instructions and consult your surgeon if you have concerns.

Returning to Work or School: The duration of your absence from work or school depends on the demands of your activities on your knee. Most individuals require a few weeks of rest at home after knee replacement surgery. Your surgeon will advise you on the safe timing for your return.