Everything You Need to Know About Knee Replacement Surgery

What is knee replacement surgery?

Knee replacement surgery is a procedure that is used to repair damaged knees. Replacement for your knee parts can help relieve pain and also make the knee joint active. For total knee replacement surgery, the doctor will remove the damaged cartilage and bone, and then replace it with man-made parts. In partial knee replacement, only one part of the knee is replaced. 

How it is carried out?

Knee replacement surgery is a procedure carried out under general anesthesia. This means that you are completely asleep when the procedure is being performed. Epidural anesthesia can also be used to numb the area of operation. With epidural anesthesia, you will be awake but your nerves below the waist are senseless.

During the operation, the worn out ends of your knee bones are removed and replaced with plastic or metal parts (a prostheses) which are measured to fit into your knee. Depending on how damaged your knee is, you can either have half or total knee replacement. Total knee replacement is common.

What are the types of Knee Replacement Surgeries?

Total Knee Replacement (TKR)

Total knee replacement, also known as total knee arthroplasty, is a procedure where both sides of your knee joints are replaced. The whole operation may take 1-3 hours. The procedure is as follows:

• Your surgical doctor makes a cut in front of your knee to get the kneecap exposed. The kneecap is moved to the side so that your surgeon can see the joint behind it.
• The damaged sides of your knee bones - tibia and femur - are cut away. The removed portions are measured so that the prostheses are cut exactly the same size. A dummy joint is then fixed for testing to make sure the joint is working well. Bone ends are cleaned, and adjustments are then made, followed by fitting of the prostheses.
• The femur end is replaced with a curved metal piece, while the tibia end is fitted with a metal plate. The fixing is accomplished using special cement which enables the complete fusion of your bones with the replacement parts. An artificial cartilage made of a plastic spacer is placed to reduce friction when your joints move.
• The back of your kneecap will also be replaced if it's been damaged.
• The wound is then closed with sutures or clips and then dressing is made over the wound. Your leg can also be restricted from movement with the use of a splint in some cases.

Total knee replacement is a common procedure compared to half knee replacement. The fitted prostheses can last up to 20 years. After this type of knee replacement, you may have problems kneeling or bending your knee due to the scar formed.

Half Knee Replacement

In this type of surgery, only one side of your knee is replaced with prostheses. This is a generally smaller operation performed when one side of your knee is damaged. During the procedure, a small cut is made and a small bone is removed. The removed bone is then replaced with prostheses. This replacement is suitable as a round one method for people who have osteoarthritis. This procedure involves shorter hospital stay duration with less blood transfusion.

With half knee replacement, you will have normal and natural knee movement. It also allows you to be more active compared to a total knee replacement.

Other types of knee replacement surgeries include:

• Kneecap replacement - This is performed only for a damaged kneecap. This procedure is also known as patellofemoral joint arthroplasty. It involves a very small surgery with less recovery time. Long term results for this procedure are not well understood and are hence not suitable in treatment of osteoarthritis.
• Mini-incision surgery - This procedure can be used for either partial or total knee replacement. The surgery involves making a smaller incision than that of standard knee replacement. Special instruments are then used to go around the knee tissue without cutting it. It has a shorter recovery period too.
• Patient-specific knee replacement - It is a more advanced procedure compared to the rest. Magnetic resonance imaging is used to guide the surgeon through the knee replacement process and also creating the best and fitting implant for every patient. The advantage of this procedure is that the implant will last longer since it is custom fitted.
• Image-guided surgery - In this procedure, your surgeon performs the knee surgery and replacement with guide of computerized images. The images are generated by joining infrared beacons to parts of your leg and also to the operating instruments.

What are the potential complications?

Anesthesia is safe but sometimes they may carry risks of side effects such as temporal confusion or sickness. The risk of death to a healthy patient is minimal.

Other complications associated with knee replacement surgery are:

• Wound infection is one thing you should expect after a knee replacement. Treatment or prevention with antibiotics is recommended. Deeply infected wound will require further surgery.
• Bleeding on the knee joint.
• Damage on the arteries and ligaments within the surrounding area of the knee joints.
• Blood clot formation or deep vein thrombosis can also occur after a knee replacement surgery. Clots can form as a result of reduced movement in the joints. Blood clots can also be prevented by avoiding blood thinner medications one week before the operation.
• Fracture on either tibia or femur may occur during or after the operation.
• Formation of excess bone around the artificial bone may be experienced. It can hinder knee movement which may require further surgery.
• Formation of an excess scar can hinder joint movement. Further surgery may be needed for this.
• Dislocation of the kneecap can be another complication after surgery.
• Use of local anesthesia on the site of surgery may numb the area around the wound.
• Allergic reactions resulting from the special cement used to join the bones and the prostheses can occur.

Bottom Line

Knee replacement surgery is a procedure performed for patients with severe knee damage. Replacement for your knee parts will help relieve pain and make the joints more active. For total knee replacement surgery, the doctor will remove the damaged cartilage and bone, and then replace it with man-made parts. In partial knee replacement, only one part of the knee is replaced.