Bilateral Knee Replacement: Understanding the Procedure, Recovery, and Risks

What is a double knee replacement called?

A double knee replacement is commonly referred to as a bilateral knee replacement. This surgical procedure involves replacing both knee joints, either simultaneously during a single operation or in two separate, staged operations.

Understanding Bilateral Knee Replacement

A bilateral knee replacement is a significant orthopedic surgery designed to alleviate severe pain and restore function in both knees. It is typically performed when both knee joints are extensively damaged by conditions such as osteoarthritis, rheumatoid arthritis, or post-traumatic arthritis, leading to debilitating pain, stiffness, and impaired mobility.

There are two primary approaches to bilateral knee replacement:

• Simultaneous Bilateral Knee Replacement: Both knees are operated on during the same surgical session. This means the patient undergoes a single anesthetic event and a single recovery period in the hospital.
• Staged Bilateral Knee Replacement: The two knee replacement surgeries are performed at separate times, usually weeks or months apart. This allows for recovery and rehabilitation of the first knee before the second surgery.

Why is a Bilateral Knee Replacement Performed?

The primary indication for a bilateral knee replacement is severe, chronic pain and functional limitation in both knees that has not responded to conservative treatments. These treatments often include medication, physical therapy, injections, and lifestyle modifications.

Common conditions that lead to the need for bilateral knee replacement include:

• Severe Osteoarthritis: Degenerative joint disease causing cartilage breakdown and bone-on-bone friction in both knees.
• Rheumatoid Arthritis: An autoimmune disease causing chronic inflammation and damage to the joint lining.
• Post-Traumatic Arthritis: Arthritis developing after a significant knee injury, such as a fracture or ligament tear.
• Significant Knee Deformity: Conditions like severe genu varum (bow-leggedness) or genu valgum (knock-knees) that affect both limbs and cause pain.

The goal of the surgery is to relieve pain, correct deformity, and improve the patient's ability to walk, stand, and perform daily activities.

The Surgical Procedure

Regardless of whether it's simultaneous or staged, the fundamental steps of a knee replacement are similar for each joint.

• Pre-operative Assessment: Before surgery, a thorough medical evaluation is conducted. This includes physical examinations, blood tests, X-rays, and potentially MRI scans to assess the extent of damage and plan the procedure. Patients are often advised to optimize their health, including weight management and cessation of smoking, to improve surgical outcomes.
• Anesthesia: The procedure is typically performed under general anesthesia, though spinal or epidural anesthesia with sedation can also be used.
• Surgical Steps:
  • An incision is made over the knee joint.
  • The damaged bone and cartilage from the end of the femur (thigh bone) and the top of the tibia (shin bone) are carefully removed. The patella (kneecap) may also be resurfaced.
  • Metal implants are cemented or press-fit onto the prepared bone surfaces, recreating the joint. A medical-grade plastic spacer is inserted between the metal components to allow for smooth gliding movement.
  • The incision is then closed with sutures or staples.

Recovery and Rehabilitation

Recovery from bilateral knee replacement is a demanding but crucial process, central to achieving optimal outcomes.

• Immediate Post-operative Phase: Pain management is a priority, often involving a combination of medications. Early mobilization is encouraged, with patients typically beginning to stand and walk with assistance within 24 hours of surgery.
• Hospital Stay: The duration of the hospital stay varies but is generally longer for simultaneous bilateral procedures (e.g., 3-7 days) compared to unilateral or staged procedures. Initial physical therapy begins in the hospital, focusing on range of motion and initial strengthening exercises.
• Physical Therapy: This is the cornerstone of recovery. A structured physical therapy program will involve:
  • Range of Motion Exercises: To restore the knee's ability to bend and straighten.
  • Strengthening Exercises: Targeting the quadriceps, hamstrings, and gluteal muscles to support the new joint.
  • Gait Training: Re-learning to walk properly, often with the aid of crutches or a walker initially.
  • Balance and Proprioception Training: To improve stability and body awareness.
• Long-Term Recovery: Full recovery can take anywhere from 6 to 12 months, or even longer for some individuals, particularly after simultaneous bilateral surgery. Consistency with home exercises and adherence to physical therapy recommendations are vital for a successful outcome.

Potential Risks and Complications

While generally safe and effective, like any major surgery, bilateral knee replacement carries potential risks. These risks are often slightly elevated with simultaneous bilateral procedures compared to single-knee replacements due to the increased physiological stress on the body.

• General Surgical Risks:
  • Infection: Though rare, a serious complication that may require further surgery.
  • Blood Clots: Deep vein thrombosis (DVT) in the leg veins, which can potentially travel to the lungs (pulmonary embolism).
  • Nerve or Blood Vessel Damage: Injury to surrounding structures.
  • Anesthesia Risks: Adverse reactions to anesthetic agents.
• Specific to Knee Replacement:
  • Stiffness or Limited Range of Motion: Despite therapy, some patients may not regain full flexibility.
  • Loosening or Wear of Implants: Over time, the prosthetic components can loosen or wear out, potentially requiring revision surgery.
  • Periprosthetic Fracture: A fracture around the implant.
  • Patellar (Kneecap) Complications: Pain or tracking issues.

Considerations for Candidates

Deciding on a bilateral knee replacement involves careful consideration, especially given the intensive recovery process.

• Overall Health: Candidates should be in good general health, particularly regarding cardiovascular and pulmonary function, as the surgery places considerable stress on the body. Pre-existing conditions must be well-managed.
• Patient Motivation and Commitment: The success of the surgery heavily relies on the patient's dedication to the rigorous physical therapy and rehabilitation program.
• Support System: Having a strong support system at home is crucial, especially in the initial weeks post-surgery, as daily tasks will be challenging. Assistance with cooking, cleaning, and personal care is often necessary.

Life After Bilateral Knee Replacement

For most patients, bilateral knee replacement significantly improves quality of life.

• Expected Outcomes: The vast majority experience substantial pain relief and improved mobility, allowing them to resume many daily activities with greater ease.
• Activity Guidelines: Low-impact activities like walking, swimming, cycling, and golf are generally encouraged. High-impact sports or activities involving jumping or twisting (e.g., running, contact sports, skiing) are typically discouraged to protect the implants and prevent premature wear.
• Implant Longevity: Modern knee implants are designed to last 15 to 20 years or more in 85-90% of patients. Regular follow-up appointments with the orthopedic surgeon are recommended to monitor the health of the implants and the joint.

A bilateral knee replacement, while a major undertaking, can provide profound relief and restore functional independence for individuals suffering from severe, debilitating arthritis in both knees. Careful consideration, thorough preparation, and dedicated rehabilitation are key to achieving the best possible outcomes.