Knee replacement, also known as knee arthroplasty, is a surgical procedure to replace the weight-bearing surfaces of the knee joint to relieve pain and restore function. It is one of the most common and successful orthopedic procedures, with over a million surgeries performed worldwide annually. This procedure is typically recommended for individuals suffering from severe arthritis or significant knee injuries that do not respond to non-surgical treatments.

Types of Knee Replacement

1. Total Knee Replacement (TKR)

  • Involves replacing the entire knee joint.
  • Both the femur (thighbone) and tibia (shinbone) surfaces are resurfaced, and in some cases, the patella (kneecap) is also replaced.
  • Suitable for patients with advanced arthritis affecting the entire knee joint.

2. Partial Knee Replacement (PKR)

  • Also known as unicompartmental knee replacement.
  • Only the damaged portion of the knee joint is replaced, preserving the healthy bone and cartilage.
  • Ideal for patients with damage confined to one compartment of the knee.

3. Kneecap Replacement

  • Replaces only the underside of the kneecap and its groove (patellofemoral compartment).
  • Recommended for patients with isolated patellofemoral arthritis.

4. Revision Knee Replacement

  • A secondary surgery to replace or repair a previously implanted artificial knee joint.
  • Necessary in cases of implant wear, loosening, infection, or persistent pain.

Indications for Knee Replacement

Primary Indications

  1. Osteoarthritis:
    • Most common cause.
    • Degenerative joint disease leading to cartilage breakdown and pain.
  2. Rheumatoid Arthritis:
    • Autoimmune disease causing chronic inflammation and joint damage.
  3. Post-Traumatic Arthritis:
    • Resulting from previous knee injury or fractures.

Other Indications

  • Severe knee pain and stiffness affecting daily activities.
  • Deformity of the knee, such as bowing or knock-knees.
  • Chronic swelling and inflammation unresponsive to treatment.
  • Failure of non-surgical treatments, including medications, physical therapy, and injections.

Preoperative Evaluation and Preparation

Clinical Assessment

  • Detailed medical history and physical examination.
  • Assessment of pain, mobility, and joint stability.

Imaging Studies

  1. X-rays:
    • To evaluate joint space narrowing, bone damage, and deformities.
  2. MRI:
    • Provides detailed images of soft tissue structures if needed.

Medical Optimization

  • Blood tests to check overall health and readiness for surgery.
  • Management of underlying conditions such as diabetes, hypertension, or obesity.

Preoperative Education

  • Counseling about the procedure, risks, benefits, and expected outcomes.
  • Demonstration of postoperative exercises and mobility aids.

The Knee Replacement Procedure

Anesthesia

  • General Anesthesia: Patient is unconscious during surgery.
  • Spinal or Epidural Anesthesia: Numbs the lower body, with the patient remaining awake but sedated.

Surgical Steps

  1. Incision and Exposure:
    • A 6-10 inch incision is made on the front of the knee to access the joint.
  2. Bone Resurfacing:
    • Damaged cartilage and bone are removed from the femur, tibia, and patella.
  3. Implant Placement:
    • Metal and plastic components are cemented or press-fitted into place.
  4. Closure:
    • The incision is closed with sutures or staples.
  5. Postoperative Dressing:
    • The knee is bandaged, and a drain may be placed to remove excess fluid.

Recovery and Rehabilitation

Immediate Postoperative Care

  1. Hospital Stay:
    • Typically lasts 1-3 days, depending on the patient’s condition.
  2. Pain Management:
    • Medications include opioids, NSAIDs, and local anesthetics.
  3. Early Mobilization:
    • Encouraged within 24 hours to prevent complications such as blood clots.

Physical Therapy

  • Begins immediately after surgery and continues for several weeks.
  • Focuses on restoring range of motion, strength, and walking ability.

Home Modifications

  • Installing grab bars, using raised toilet seats, and removing tripping hazards to ensure safety during recovery.

Risks and Complications

Common Risks

  1. Infection:
    • Superficial or deep infections requiring antibiotics or further surgery.
  2. Blood Clots:
    • Deep vein thrombosis (DVT) or pulmonary embolism (PE).
  3. Implant Issues:
    • Loosening, wear, or dislocation of the prosthetic joint.

Less Common Complications

  • Nerve or blood vessel injury.
  • Persistent pain or stiffness.
  • Allergic reactions to implant materials.

Long-Term Outcomes

Success Rates

  • Over 90% of patients experience significant pain relief and improved function.
  • Implants typically last 15-20 years with proper care.

Lifestyle Adjustments

  • Avoid high-impact activities such as running or jumping to prolong implant life.
  • Maintain a healthy weight to reduce stress on the knee joint.

Innovations in Knee Replacement

Robotic-Assisted Surgery

  • Offers greater precision and personalized alignment of implants.
  • Reduces recovery time and improves outcomes.

Custom Implants

  • Tailored to the patient’s anatomy using 3D printing technology.

Minimally Invasive Techniques

  • Smaller incisions and less tissue damage lead to faster recovery and reduced pain.

Alternatives to Knee Replacement

Non-Surgical Options

  1. Medications:
    • Pain relievers, anti-inflammatory drugs, and corticosteroid injections.
  2. Physical Therapy:
    • Exercises to strengthen muscles around the knee and improve flexibility.
  3. Assistive Devices:
    • Knee braces, canes, or walkers to reduce stress on the joint.

Surgical Alternatives

  1. Osteotomy:
    • Realignment of the knee joint to shift weight away from the damaged area.
  2. Cartilage Restoration:
    • Procedures to repair or regenerate cartilage in younger patients.

Prevention of Knee Problems

Maintaining Joint Health

  • Regular low-impact exercise such as swimming or cycling.
  • Weight management to reduce stress on the knees.
  • Adequate intake of calcium and vitamin D for bone health.

Injury Prevention

  • Use proper techniques during physical activities.
  • Wear supportive footwear and use protective gear when necessary.

Knee replacement surgery is a transformative procedure for individuals suffering from debilitating knee pain and reduced mobility. Advances in surgical techniques and implant technology have made the procedure safer and more effective, with high patient satisfaction rates.

While surgery is a significant decision, understanding the process, risks, and benefits can help patients make informed choices. With appropriate care and rehabilitation, knee replacement can restore mobility, alleviate pain, and enhance overall quality of life.

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Last Update: December 28, 2024