Knee Replacement Surgery

Reasons for Knee Replacement Surgery

The most common reasons for knee replacement surgery include:

1. Osteoarthritis: This is the most common cause of knee joint damage in older adults. Over time, the cartilage that cushions the bones in the knee wears away, leading to pain, stiffness, and limited mobility.
2. Rheumatoid Arthritis: An autoimmune disorder that causes inflammation in the joints, leading to damage in the knee.
3. Post-Traumatic Arthritis: Damage to the knee joint from an injury, such as a fracture or ligament damage, that results in the early onset of arthritis.
4. Knee Deformities: Conditions like bowlegs (varus deformity) or knock-knees (valgus deformity) that result in abnormal wear on the knee joint.
5. Other Degenerative Conditions: Chronic knee pain or disability due to degenerative conditions that have not responded to other treatments such as medication, physical therapy, or injections.

Knee replacement surgery is generally considered when:

• Knee pain limits daily activities (walking, climbing stairs, getting out of a chair, etc.).
• Non-surgical treatments, like medications, physical therapy, and injections, are no longer effective.
• The knee joint has severe arthritis or joint deformities that affect function.

Types of Knee Replacement Surgery

There are several types of knee replacement procedures depending on the severity of joint damage and the surgical approach used.

1. Total Knee Replacement (TKR)

• In a total knee replacement, the damaged parts of the femur (thigh bone), tibia (shin bone), and the kneecap (patella) are removed and replaced with prosthetic components.
• The femoral component (typically made of metal) is placed on the end of the femur, the tibial component (made of metal or plastic) is placed on the tibia, and the patellar component (a plastic button) is placed on the back of the kneecap.
• This is the most common form of knee replacement and is generally used for widespread arthritis or joint damage.

2. Partial Knee Replacement (Unicompartmental Knee Replacement)

• In a partial knee replacement, only the damaged part of the knee is replaced. This type of surgery is typically performed when arthritis affects only one compartment of the knee joint, usually the medial (inside) or lateral (outside) part.
• A partial knee replacement requires smaller incisions and preserves more of the natural bone and ligaments, which can lead to a faster recovery and less post-operative pain.
• However, it is not suitable for patients with widespread arthritis or significant damage to the knee joint.

3. Bilateral Knee Replacement

• Bilateral knee replacement refers to replacing both knees during the same surgery. This is typically done for patients who have arthritis or severe joint degeneration in both knees.
• The procedure can be performed as a staged bilateral knee replacement (one knee replaced at a time, with a gap of weeks to months between surgeries) or a simultaneous bilateral knee replacement (both knees replaced in one surgery).

4. Minimally Invasive Knee Replacement

• Minimally invasive techniques use smaller incisions and advanced surgical instruments, which can lead to less pain, fewer complications, and faster recovery compared to traditional knee replacement surgery.
• This approach is not suitable for all patients, especially those with severe deformities or complex knee problems.

The Knee Replacement Surgery Procedure

Knee replacement surgery typically takes about 1 to 2 hours, and it is performed under either general anesthesia (where the patient is asleep) or spinal/epidural anesthesia (where the lower body is numbed). The procedure involves the following steps:

1. Incision: A surgical incision is made along the front of the knee, usually between 6 to 10 inches in length.
2. Bone Preparation: The damaged surfaces of the femur and tibia are carefully removed, and the remaining bone is shaped to fit the prosthetic components.
3. Implant Placement: The metal and plastic components are securely placed in the knee joint. The femoral component is fixed to the end of the femur, the tibial component is placed on the tibia, and if necessary, the patella is resurfaced with a plastic component.
4. Checking the Alignment: The surgeon ensures that the components are correctly aligned and that the knee moves smoothly.
5. Closing the Incision: After the implant is in place, the surgeon closes the incision with stitches or staples.
6. Recovery: The patient is moved to a recovery room and closely monitored as they wake up from anesthesia.

Recovery After Knee Replacement Surgery

1. Immediate Post-Op Care

• Hospital Stay: After surgery, the patient typically stays in the hospital for 1 to 3 days. Pain management is an important aspect of recovery and may involve medication, ice, and elevation.
• Physical Therapy: Physical therapy starts soon after surgery to help improve joint mobility, strength, and function. The patient will be encouraged to move the knee and begin gentle exercises to prevent stiffness and improve flexibility.
• Pain Management: Pain medication, including opioids or nonsteroidal anti-inflammatory drugs (NSAIDs), may be prescribed to manage pain in the first few days after surgery.

2. Long-Term Recovery

• Walking and Weight-Bearing: Most patients are encouraged to start walking with assistance (e.g., a walker or crutches) on the same day or the day after surgery. Full weight-bearing is usually allowed within a few days to weeks, depending on the patient’s progress.
• Physical Therapy: The patient will need to continue physical therapy for several weeks or months to regain strength, mobility, and function. The therapist will focus on exercises to improve flexibility, strength, balance, and walking.
• Follow-up Appointments: Regular follow-up visits with the orthopedic surgeon are necessary to monitor progress, ensure proper healing, and check the alignment of the implants.

3. Full Recovery Time

• It can take 3 to 6 months for the knee to fully heal and for the patient to regain most of their function. However, the final outcome can take up to a year, with many patients feeling significant improvements in pain and function within the first few months.

Risks and Complications of Knee Replacement Surgery

While knee replacement surgery is generally safe, like all surgeries, it carries some risks. Possible complications include:

1. Infection: A risk of infection exists at the surgical site or deeper in the joint.
2. Blood Clots: Blood clots (deep vein thrombosis or DVT) can form in the legs, which could travel to the lungs (pulmonary embolism). Blood thinners and exercises help reduce this risk.
3. Implant Loosening or Failure: Over time, the prosthetic components may wear out or loosen, requiring revision surgery.
4. Nerve or Blood Vessel Damage: In rare cases, the nerves or blood vessels around the knee may be injured during surgery.
5. Stiffness: Some patients may experience limited range of motion or stiffness in the knee joint.
6. Persistent Pain: Some patients may continue to experience pain or discomfort after surgery, though this is usually much less than before the operation.
7. Instability: In some cases, patients may experience a feeling of instability or that the knee might give way.
8. Allergic Reaction: Rarely, patients may have an allergic reaction to the materials used in the prosthesis, such as metals or plastics.

Life After Knee Replacement

Knee replacement surgery can dramatically improve the quality of life for those suffering from chronic knee pain and disability. Many people report significant pain relief, improved mobility, and the ability to return to everyday activities. However, it’s important to note that:

• Activity Modification: Patients should avoid high-impact activities like running or jumping, as they can wear out the prosthetic joint more quickly. Low-impact activities, such as walking, swimming, and cycling, are encouraged.
• Weight Management: Maintaining a healthy weight is important for reducing stress on the new knee joint.
• Longevity of the Implant: Modern knee replacements are designed to last 15 to 20 years or more, but it’s important to follow your surgeon’s recommendations to extend the life of the implant.

Conclusion

Knee replacement surgery is a highly effective procedure for treating severe knee pain and disability due to arthritis or injury. The surgery can significantly improve mobility, function, and quality of life, particularly in people who have not found relief from other treatments. While recovery takes time, most patients experience substantial pain relief and are able to return to normal activities with proper rehabilitation. However, like any major surgery, knee replacement does come with risks, and it’s important for patients to discuss their options and expectations with their orthopedic surgeon to ensure the best outcome.