Total knee replacement (TKR), also known as total knee arthroplasty, is a surgical procedure in which a damaged or diseased knee joint is replaced with an artificial implant. This surgery is typically recommended for patients with severe knee pain or dysfunction due to conditions like osteoarthritis, rheumatoid arthritis, or traumatic injury.

Indications for Total Knee Replacement

• Severe Osteoarthritis: The most common reason for TKR, where the cartilage in the knee joint is worn down, causing pain, stiffness, and reduced mobility.
• Rheumatoid Arthritis: An autoimmune condition that leads to chronic inflammation and damage to the knee joint.
• Post-Traumatic Arthritis: Arthritis that develops after a knee injury, leading to joint damage and pain.
• Failed Conservative Treatments: When non-surgical treatments like medications, physical therapy, or injections have not provided relief.

The Surgical Procedure

1. Preoperative Evaluation

   • Medical Assessment: Comprehensive evaluation of the patient’s overall health, including blood tests, imaging studies (X-rays, MRI), and a review of medical history.
   • Pre-Surgical Planning: Detailed planning of the surgery, including the selection of the appropriate implant size and type.

2. Surgery

   • Anesthesia: The procedure is typically performed under general anesthesia or spinal anesthesia.
   • Incision: A surgical incision is made at the front of the knee to access the joint.
   • Removal of Damaged Tissue: The damaged cartilage and bone are removed from the femur (thigh bone), tibia (shin bone), and patella (kneecap).
   • Implant Placement: The artificial components (prosthesis) are fitted to the prepared bone surfaces. The components are typically made of metal and plastic and are designed to replicate the movement of a natural knee joint.
   • Alignment and Balance: The surgeon ensures proper alignment and balance of the knee joint to optimize function and longevity of the implant.
   • Closure: The incision is closed with sutures or staples, and a dressing is applied.

3. Types of Implants

   • Fixed-Bearing Implants: The most common type, where the plastic component is attached firmly to the metal component.
   • Mobile-Bearing Implants: Allows for slight rotation within the knee joint, offering potentially greater flexibility.
   • Posterior-Stabilized Implants: Used when the posterior cruciate ligament (PCL) is removed during surgery.
   • Cruciate-Retaining Implants: Designed to retain the PCL, allowing for more natural knee movement.

Postoperative Care and Recovery

1. Hospital Stay

   • Patients usually stay in the hospital for 2-3 days post-surgery, although some may be discharged the same day.
   • Pain management is provided through medications.

2. Physical Therapy

   • Early mobilization is encouraged to prevent stiffness and improve circulation.
   • A structured physical therapy program is essential to regain strength, flexibility, and range of motion in the knee.

3. Rehabilitation

   • Rehabilitation typically continues for several weeks to months, with gradual increases in activity levels.
   • Most patients can resume normal activities within 3-6 months, though full recovery may take up to a year.

4. Long-Term Care

   • Regular follow-up visits are necessary to monitor the implant and knee function.
   • Patients are advised to avoid high-impact activities to prolong the life of the implant.

Risks and Complications

• Infection: Though rare, infection can occur in the wound or deep around the implant.
• Blood Clots: Deep vein thrombosis (DVT) is a potential risk, so blood-thinning medications may be prescribed.
• Implant Loosening or Wear: Over time, the implant may loosen or wear out, possibly requiring revision surgery.
• Stiffness or Limited Range of Motion: Some patients may experience stiffness or limited mobility after surgery.

Outcomes

• Pain Relief: Most patients experience significant pain relief after TKR.
• Improved Mobility: The majority of patients regain better knee function and mobility, allowing them to return to daily activities.
• Durability: Modern implants are designed to last 15-20 years or more, depending on the patient’s activity level and overall health.