Knee Replacement Surgery

What is Knee Replacement Surgery?

Knee replacement surgery (also known as knee arthroplasty) is a surgical procedure where damaged or diseased parts of the knee joint are removed and replaced with artificial components (prostheses). The knee joint is a hinge joint formed by the lower end of the thighbone (femur), the upper end of the shinbone (tibia), and the kneecap (patella). Over time, injury, arthritis, or wear and tear can damage the cartilage cushioning these bones, leading to pain, stiffness, and limited mobility. Knee replacement surgery is performed to relieve pain, restore function, and improve the quality of life when conservative treatments, such as medication, physical therapy, or lifestyle modifications, are no longer effective.

Types of Knee Replacement (Total vs. Partial)

There are two primary types of knee replacement surgeries

Total Knee Replacement (TKR) 

In this procedure, the entire knee joint is replaced. The damaged surfaces of the femur, tibia, and often the kneecap are removed and replaced with metal or plastic prosthetic components. TKR is the most common type of knee replacement surgery, offering long-lasting pain relief and improved joint function.

Partial Knee Replacement (PKR)

Also known as unicompartmental knee replacement, this procedure involves replacing only the damaged portion of the knee. The surgery is less invasive than TKR, as it preserves healthy parts of the knee joint. PKR is suitable for patients with localized arthritis affecting only one part of the knee. It has a faster recovery time but may not be as durable as TKR.

Indications for Knee Replacement

Knee replacement is generally recommended for individuals experiencing significant pain, stiffness, or loss of function due to conditions affecting the knee joint. Common indications for knee replacement include:

• Osteoarthritis: The most common reason for knee replacement surgery. Osteoarthritis is a degenerative joint disease that wears away the cartilage, causing bones to rub together, resulting in pain and stiffness.
• Rheumatoid Arthritis: An autoimmune condition that causes inflammation in the joints, leading to pain, swelling, and joint damage.
• Post-Traumatic Arthritis: Arthritis that develops after a serious knee injury, such as a fracture or ligament tear, leading to joint degeneration.
• Knee Deformities: Conditions like bow-leggedness (varus) or knock-knees (valgus) can cause abnormal stress on the knee joint, leading to cartilage damage and pain.
• Severe Knee Pain: Persistent pain that limits daily activities, such as walking, climbing stairs, or getting up from a seated position, especially when other treatments have failed.
• Loss of Mobility: Limited ability to move the knee joint, even with conservative treatments like physical therapy and medications.

Knee replacement is usually considered when non-surgical treatments no longer provide relief, and the patient’s quality of life is significantly affected by knee pain and dysfunction.

The Knee Replacement Procedure

The knee replacement procedure typically involves the following steps:

1. Anesthesia: The patient is given general anesthesia (where the patient is fully unconscious) or spinal anesthesia (which numbs the lower part of the body).
2. Incision: The surgeon makes an incision in the front of the knee to access the joint. The length of the incision depends on the type of procedure and whether it is minimally invasive or traditional.
3. Removal of Damaged Tissue: The surgeon removes the damaged cartilage and bone from the femur, tibia, and possibly the back of the kneecap (patella).
4. Placement of Prosthesis: The removed tissues are replaced with artificial components. The femoral component (made of metal) is placed on the end of the femur, and the tibial component (metal with a plastic spacer) is placed on the top of the tibia to allow smooth movement. In some cases, the undersurface of the kneecap is replaced with a plastic component.
   • The components are secured using bone cement or may be “cementless,” relying on bone growth for fixation.
5. Alignment and Testing: The surgeon checks the alignment of the new knee joint and ensures it moves properly. The incision is then closed with stitches or surgical staples.

The procedure typically lasts about 1-2 hours, depending on the complexity of the case and the type of knee replacement being performed.

Benefits of Knee Replacement

Knee replacement surgery offers numerous benefits for individuals suffering from chronic knee pain and limited mobility:

• Pain Relief: The primary benefit of knee replacement is the significant reduction or elimination of chronic knee pain, allowing patients to move more comfortably.
• Improved Mobility and Function: Replacing the damaged knee joint restores the ability to walk, climb stairs, and engage in daily activities that were previously difficult due to pain or stiffness.
• Enhanced Quality of Life: With less pain and improved knee function, patients can return to activities they enjoy, such as walking, traveling, or participating in sports.
• Long-Lasting Results: Modern knee prostheses are designed to last 15-20 years or longer, providing long-term relief from arthritis and joint damage.
• Correction of Deformities: Knee replacement can correct alignment issues, such as bow-legged or knock-knee deformities, improving the overall stability of the knee.

Recovery from Knee Replacement

Recovery after knee replacement surgery involves a combination of rest, physical therapy, and gradual return to normal activities. The recovery timeline may vary based on the individual’s overall health and the type of procedure performed, but here’s a general outline:

• Hospital Stay: Most patients stay in the hospital for 2-3 days following the surgery. In some cases, patients undergoing minimally invasive surgery may be discharged on the same day.
• Pain Management: Pain is managed with medications such as opioids, NSAIDs, and local anesthetics. Some patients may also be given blood thinners to prevent blood clots.
• First Week: Physical therapy usually begins within 24 hours after surgery. Patients are encouraged to start walking with the help of a walker or crutches. The therapist will guide exercises to improve knee movement and strengthen the surrounding muscles.
• 2-4 Weeks: Most patients can walk short distances without the help of a walker or crutches and gradually return to normal activities, such as driving (usually within 4-6 weeks), depending on recovery progress.
• 3 Months: By this time, most patients regain the ability to walk without assistance, climb stairs, and perform daily activities with little or no pain.
• 6 Months to 1 Year: Full recovery, including the return of strength, flexibility, and endurance, typically occurs within 6-12 months after surgery.

Patients are advised to follow their doctor’s recommendations closely during recovery to avoid complications such as blood clots, infection, or implant loosening.

Post-Surgical Care and Physiotherapy

Post-surgical care and physiotherapy are essential for a successful recovery and optimal function after knee replacement surgery.

Key Components of Post-Surgical Care:

• Wound Care: Keep the incision site clean and dry to prevent infection. Follow the surgeon’s instructions for wound care, including when to change bandages and when to shower.
• Pain Management: Pain medication is prescribed to help manage post-operative pain. Ice packs and elevation of the leg can also help reduce swelling and discomfort.
• Blood Clot Prevention: Patients are encouraged to move their feet and legs regularly, wear compression stockings, and take prescribed blood thinners to prevent blood clots.

Physiotherapy and Rehabilitation:

• Early Movement: Patients are encouraged to begin walking with assistance soon after surgery to promote circulation, prevent stiffness, and reduce the risk of complications.
• Range of Motion Exercises: Physical therapists will guide the patient through exercises to regain full movement in the knee joint. This includes bending, straightening, and strengthening exercises for the muscles around the knee.
• Strengthening Exercises: Strengthening the quadriceps, hamstrings, and calf muscles is crucial for supporting the new knee joint and improving overall function.
• Balance and Stability: As patients progress through rehabilitation, exercises to improve balance and stability are introduced to prevent falls and enhance mobility.
• Long-Term Maintenance: Ongoing physical therapy may be recommended for several months to ensure long-term success and prevent stiffness or weakening of the muscles.

Resuming Activities:

• Patients can typically return to low-impact activities such as walking, swimming, or cycling within a few months of surgery.
• High-impact activities like running or contact sports should be avoided to prevent stress on the artificial joint.

Adhering to the prescribed physiotherapy program is essential for ensuring the success of the knee replacement and for achieving the best possible outcome.