Knee Arthroplasty - Dr. Nabeel Mahomed

What is Knee Arthroplasty?

Knee arthroplasty, commonly known as knee replacement surgery, is a surgical procedure where damaged parts of the knee joint are removed and replaced with artificial components called prostheses. These prosthetic parts replicate the natural function of the knee, relieving pain and improving mobility for patients suffering from various knee conditions.

The knee is the largest joint in the body and one of the most complex. It consists of the lower end of the femur (thigh bone), the upper end of the tibia (shin bone), and the patella (kneecap). In a total knee replacement, all three components may be replaced with prosthetic parts designed to move like a natural knee.

When is Knee Replacement Needed?

Knee replacement surgery is typically recommended when knee pain and functional limitations significantly affect a patient's quality of life and conservative treatments have not provided adequate relief. Common conditions that may lead to the need for knee replacement include:

Osteoarthritis

The most common cause for knee replacement, osteoarthritis involves the wearing away of joint cartilage, leading to pain, stiffness, and reduced mobility.

Rheumatoid Arthritis

An inflammatory condition where the immune system attacks the synovial membrane, causing pain, inflammation, and eventual damage to the cartilage and bone.

Post-traumatic Arthritis

May develop after a severe knee injury, such as fractures, torn ligaments, or meniscal tears, causing damage to the articular cartilage over time.

Severe Deformity

Conditions like bow legs (genu varum) or knock knees (genu valgum) that progressively worsen and cause pain and instability.

Types of Knee Replacement

There are several approaches and techniques for knee replacement surgery. Dr. Nabeel Mahomed specializes in various techniques and will recommend the most appropriate option based on your specific condition, age, activity level, and overall health.

Total Knee Replacement (TKR)

All three compartments of the knee joint (medial, lateral, and patellofemoral) are replaced with prosthetic components. The femoral component (metal) caps the end of the thigh bone, the tibial component (metal and plastic) replaces the top of the shin bone, and the patellar component (plastic) replaces the undersurface of the kneecap.

Partial Knee Replacement (PKR)

Also known as unicompartmental knee replacement, only the damaged compartment of the knee (usually the medial/inner or lateral/outer compartment) is replaced, preserving the healthy portions of the knee. This procedure is less invasive with a potentially faster recovery but is only suitable for certain patients.

Patellofemoral Replacement

Only the patellofemoral joint (where the kneecap meets the thigh bone) is replaced. This is suitable for patients whose arthritis is limited to this specific area of the knee.

Revision Knee Replacement

A procedure to replace a previous knee implant that has worn out, become loose, infected, or developed complications. Revision surgery is typically more complex than primary knee replacement.

The Surgical Procedure

Knee replacement surgery is usually performed under spinal or general anesthesia and typically takes 1-2 hours. The surgical approach may vary based on the patient's specific condition and the surgeon's expertise.

Dr. Mahomed specializes in various surgical approaches, including:

Traditional Approach: A vertical incision (8-10 inches) is made at the front of the knee to access the joint.
Minimally Invasive Approach: Smaller incisions (4-6 inches) and specialized instruments are used to potentially reduce tissue trauma and recovery time.
Computer-Assisted Surgery: Advanced technology helps the surgeon achieve precise alignment and positioning of implants.

During the procedure, the damaged cartilage and bone are removed from the knee joint surfaces. Precision cutting guides are used to ensure accurate bone removal. The prosthetic components are then secured to the femur, tibia, and sometimes the patella using bone cement or press-fit techniques. A plastic spacer is inserted between the metal components to allow for smooth gliding motion.

Recovery and Rehabilitation

Recovery from knee replacement surgery varies from patient to patient but typically follows this general timeline:

Hospital Stay

Most patients stay in the hospital for 1-3 days after surgery. During this time, pain management begins, and you'll work with physical therapists to learn exercises and how to walk with assistive devices.

Early Recovery (0-6 weeks)

You'll begin using walking aids like a walker or crutches. Physical therapy focuses on increasing range of motion, strengthening exercises, and gait training. Most patients can resume light activities and driving within 4-6 weeks.

Intermediate Recovery (6-12 weeks)

Walking aids are typically phased out as strength improves. Physical therapy advances to more challenging exercises. Many patients return to work and low-impact activities during this period.

Long-term Recovery (3-12 months)

The new knee joint continues to strengthen. Most patients can resume normal activities, including swimming, cycling, walking, and golf, by 6 months. High-impact activities may be restricted long-term to prolong implant life.

Physical therapy is a crucial component of recovery from knee replacement surgery. Dr. Mahomed and his team will design a personalized rehabilitation program to help you regain strength, flexibility, and function in your new knee joint. Adhering to this program is essential for optimal outcomes.

Potential Risks and Complications

While knee replacement surgery is generally safe and effective, like any major surgery, it carries some risks. These may include:

Infection at the incision site or around the prosthesis
Blood clots in the leg veins or lungs
Stiffness in the knee
Persistent pain or dissatisfaction
Loosening or wear of the prosthetic components over time
Nerve or blood vessel injury
Fracture during or after surgery
Patella (kneecap) complications

Dr. Mahomed and his team take numerous precautions to minimize these risks, including the use of antibiotics, blood thinners, and careful surgical technique. You will also receive detailed instructions on how to reduce risks during your recovery period.

Long-term Outcomes and Expectations

Knee replacement surgery is one of the most successful orthopedic procedures, with high patient satisfaction rates. More than 90% of modern knee replacements are still functioning well 15 years after surgery. Most patients experience significant pain relief and improved mobility following surgery, allowing them to resume many activities they previously avoided due to knee pain.

Modern knee implants are designed to last 15-20 years or longer, though this can vary based on factors such as activity level, weight, and overall health. Younger, more active patients may eventually require revision surgery if their implant wears out during their lifetime.

To maximize the longevity of your knee implant, Dr. Mahomed may recommend:

Maintaining a healthy weight to reduce stress on the joint
Avoiding high-impact activities such as running or jumping
Participating in regular low-impact exercise like swimming, cycling, or walking
Attending follow-up appointments to monitor the condition of your implant
Taking preventive antibiotics before dental or surgical procedures to reduce the risk of infection

Frequently Asked Questions

How do I know if I need a knee replacement?

If you experience severe knee pain that limits daily activities, difficulty walking or climbing stairs, pain that persists even when resting, knee deformity (bowing in or out), or failed conservative treatments like medication or physical therapy, you might be a candidate. Dr. Mahomed will conduct a thorough evaluation including physical examination, medical history review, and imaging studies to determine if knee replacement is appropriate for you.

What is the difference between total and partial knee replacement?

In total knee replacement, all three compartments of the knee joint are replaced with prosthetic components. In partial knee replacement, only the damaged compartment is replaced, preserving the healthy portions of the knee. Partial knee replacement is less invasive with potentially faster recovery but is only suitable for certain patients whose arthritis is limited to one compartment of the knee.

Will I be able to kneel after knee replacement?

Kneeling ability varies among patients after knee replacement. While the prosthesis itself isn't damaged by kneeling, some patients experience discomfort or find it difficult due to scar tissue, reduced sensation, or psychological concerns. Specialized physical therapy techniques may help improve comfort with kneeling, but not all patients regain this ability fully.

How painful is recovery from knee replacement?

Pain levels vary among patients. Most experience moderate to severe pain in the first few days after surgery, which is managed with medication. Pain typically improves significantly within two weeks and continues to diminish over the next few months. Modern pain management techniques, including nerve blocks, local anesthetics, and multimodal pain medication approaches, help make recovery more comfortable than in the past.

Will my knee replacement set off metal detectors?

Many knee replacements will trigger airport security alarms. If this concerns you, inform security personnel about your implant before screening. You can request documentation confirming your knee replacement, though formal medical cards are not typically needed.

Knee Arthroplasty (Knee Replacement)