Knee Replacement

A knee replacement surgery replaces a diseased knee joint with an artificial knee joint. The artificial joints are of two types, metal or ceramic.

The knee is one of the most important joints in your body. It helps you to stand up, walk, and even sit. There are two bones in the knee joint, namely the femur or the thigh bone, tibia, or the shinbone.

Your kneecap or patella lies on top of it and protects the joint. There are various muscles, ligaments, and tendons that help to stabilize the joint. Cartilages cover the end of the bones to help the bones move without any friction.

Any disease to your knee joint can make it difficult for you to walk or even stand. Degenerative diseases like arthritis can cause severe pain, swelling, or stiffness of the joint. As these diseases progress, you will have pain even at rest or while lying down.

The pain occurs due to the friction that occurs when the bones rub against each other as they move. The reason is the wear and tear of the cartilages that provides the lubrication to the joint.

During a knee replacement surgery, the artificial implants will replace the ends of the femur and the tibia. This surgery will help you to get rid of the pain and improve your movements.

The implants used for replacement are very durable and usually last the lifetime of the person having the surgery.

The duration of the surgery will be 3 to 4 hours, and you will be in the hospital for about two days. 

When do you need Knee replacement surgery?

A knee problem can affect the quality of your life by making it difficult for you to move around. You will not feel good if you need help or support to walk around.

It affects a person not only physically but also emotionally and socially. A knee replacement surgery can help you to be independent, as you were before. 

The degeneration or wearing out of the knee is the most common reason for a knee transplant. A worn-out knee joint will not have any lubrication.

The articular cartilage provides lubrication in the joints. It will aid the smooth movement of the bones, namely the femur and tibia, over each other. As the articular cartilage wears off due to constant use or disease, there will be a lot of friction when the bones glide over each other.

The friction causes pain as well as a lot of pressure on the ligaments, tendons, and muscles that keep the joint stable. It can cause swelling of these tissues in the knee.

The pain and associated swelling will make it difficult for you to walk, stand, bend your knees, etc. As the damage increases, you might feel pain at rest as well. When that happens, it is time for you to think of knee replacement surgery.

The most common condition that causes a  degeneration of the knee joints is osteoarthritis. Osteoarthritis occurs due to mechanical wear and tear of the joint. Other common diseases that cause degeneration of the knee include

• Rheumatoid arthritis 
• Gout
• Hemophilia
• Knee injury due to trauma        

Knee Replacement surgery – Preparation 

A knee replacement surgery will limit your normal activities at home and office. So you need to make necessary arrangements at both places

You will not be able to climb stairs for a few days.  So if your bedroom is upstairs, consider changing a room on the first floor to a temporary bedroom. This way, you can avoid climbing stairs.

If you are overweight, try losing a few kilos. It will help to reduce the stress on the implanted knee joint.

If you smoke, you should consider quitting. You should stop smoking a month before surgery, and continue till you have recovered completely. Smoking can adversely affect the healing of your surgical wound. It can also delay your recovery.

You will have to discuss with the surgeon regarding any medicines that you are regularly taking. Blood-thinning medications and certain herbal supplements can cause excessive bleeding during surgery. You will have to stop these as prescribed by the surgeon.

After a knee replacement, you will have to do specific physical exercises to improve the mobility of the joint. Practicing these before the surgery will make it easy for you afterward.

Types of knee implants

Four types of knee implants are the most common. They are

1. Metal on plastic. It is the most common type of knee implant. It has a femoral metal component and a polyethylene spacer attached to the tibial component. The commonly used metals are cobalt-chromium, titanium, zirconium, and nickel.
2. Ceramic on plastic. The femoral component is made of ceramic instead of metal and has a plastic spacer attached to the tibial end.
3. Ceramic on ceramic. In this, both the femoral and tibial ends will have ceramic implants
4. Metal on metal. The femoral and tibial ends are metallic

In some, the plastic used in the implants can cause an allergic reaction. In such cases, the surgeon will avoid using plastic implants. Ceramic implants can create some sounds while walking, and cannot bear a lot of stress. Your surgeon will decide the type of implant according to your needs and budget.  

Knee replacement surgery- Procedure

You will be under general anesthesia during the knee replacement surgery. In certain situations, you may have spinal or epidural anesthesia. 

The surgery will take about 2 to 3 hours.

During a knee replacement surgery, the surgeon will remove the ends of the femur and tibia and the worn-out cartilages. The metal or ceramic implants are then attached to the end of the bones. A plastic spacer will be attached to the head of the tibia for smooth movements.

The next step will be the resurfacing of the patella of the kneecap. The surgeon will then close the incisions with sutures or surgical staples.

After you recover from the effects of anesthesia, you will go back to the room where you will remain for the next two or three days.      

Knee replacement surgery Recovery

You will be in the hospital for 3-4 days. The recovery and rehabilitation process will begin right from the first day of surgery.

The first day, after the surgery, the doctor will encourage you to stand up and walk using a walker under the instructions of their physical therapist. You must start using the new knee as soon as possible.

After the first day, the distance you will walk will increase slowly. You will use a CPM (continuous passive motion) machine to keep the knee in constant motion. It helps to prevent the build-up of scar tissue around the knee.

You can go back home on the second or third day of surgery. By this time, you will be able to stand up, walk, bend your knees. You will have a cane or walker to walk around and to help you balance properly, if necessary.

Before going home, the physical therapist will instruct you about various knee- strengthening exercises and knee-bending exercises. You will do it regularly to attain greater flexibility and to reduce the build-up of scar tissue. Strengthening the muscles around your knee is essential to avoid pressure on the new joint.

Your surgeon will also tell you about what to do and what not to do after surgery. You will have to follow it for faster recovery and to avoid complications. 

Dos and Don'ts following the Knee replacement surgery

Do

• Follow physiotherapy exercise schedule
• Sit only on straight-back chairs
• Keep climbing stairs to the minimum
• Avoid running

Don't

• Twist your knee
• Squat on the floor
• Kneel on your knees
• Use recliners to relax.

Knee replacement surgery- Risks and complications

Knee replacement surgery is a safe surgical procedure with very few complications. However, very rarely, there may be some side effects as well. Most of these are minor and can be taken care of very quickly. 

The chances of patients complications depend a lot on the overall health of the patient, their age, and immunity. The following complications can occur after  a knee replacement surgery:

• Blood clots: Should a patient develop blood clots in the deep vein of their legs, doctors will recommend the use of special stockings to check this issue. You will have to take medications as well.
• Infections: Infections are a risk almost all surgeries carry. Proper care of the incision is critical after any surgery. Following the doctor's instructions on how to care for the wound can help in minimizing this risk.
• Nerve/Tissue Damage: In rare cases, there might be some damage to the arteries, cartilages, or nerves around the knee. It may require further surgery to correct the issue.
• Stiffness: The patient may also face some amount of stiffness in their knee after the surgery. You may need more physical therapy to fix this issue
• Allergic reactions: On some occasions, a patient may get allergic reactions to the metal used during the implant. If a patient is allergic to certain metals or is generally prone to allergies, they should discuss it with the surgeon