Primary Knee Joint Replacement

Primary Knee Replacement

When pain is severe and your walking is decreased because of pain or you are unable to perform your daily routine activities then you may need knee joint replacement surgery. Sometimes a Total Knee Replacement is the only option for reducing pain and restoring a normal activity .

A total knee replacement involves cutting away the damaged cartilage and bone of the knee joint and replacing it with a prosthesis. This “new joint” prevents the friction between bones and restores at the normal alignment of knee which in turn causes ligaments to work more efficiently. knee joint replacement provides a smooth knee joint

Implant

• Femoral component made of alloys.
• Tibia base plate made up of alloys.
• Spacer between tibial and femoral components made up of highly crossed linked polyethylene(Plastic).
• Patella component made up of polyethylene (plastic)

Implant Components

In the total knee replacement procedure, knee joint is made up of four parts. The tibial component has two elements and replaces the worn out tibial cartilage and bone. This part is made up of a metal tray attached directly to the bone with help of bone cement and a plastic spacer that provides the bearing surface which aids in smooth movement between tibial component and femur component. The femoral component replaces the bottom of the thigh bone or femur. This component also replaces the groove where the patella, or kneecap, sits.

The patellar component replaces the surface of the knee cap, which rubs against the femur. The patella protects the joint, and the resurfaced patellar button will slide smoothly on the front of the joint.

The Procedure

Before surgical procedure you will be given some oral and injectable medications which will not only help you to relax buy also help your body to get ready for surgery. anesthesiologist will talk with you about the medications he’ll be using. In the operating room, you will be given spinal anaesthesia which will make your lower limbs to become numb and pain free.

Advantage of giving only spinal anaesthesia and using multimodal pain management protocol helps in better pain control and early mobilisation after surgery.

Surgery

Surgery begins by making an incision on your leg to allow access to the knee joint. Surgeon then expose the joint and place a cutting jig or template on the end of the femur bone. This jig allows the surgeon to cut the bone precisely so that the prosthesis fits exactly. Once the femur is cut, the tibia is cut using another jig for proper alignment of the knee prosthesis. The undersurface of the patella is then removed.

Now it’s time to place the prosthesis. This begins with the femoral prosthesis, which is cemented in place using a special bone cement. Next the metal tray is attached to the top of the tibia. This will provide the weight-bearing surface of the femur. The plastic spacer is then attached to the metal tray. This will provide the weight-bearing surface and smooth movement between tibial and femoral components. Size of plastic vary according to the ligament laxity and tightness of your knee. Next the patellar button is cemented in place behind the knee cap. Finally, the incision is closed, and the post-operative bandaging is applied.

Returning Home

You will be discharged in 3 to 4 days after surgery. If you are suitable for day care Total knee replacement thenyou can get discharge on same day of surgery.

During your stay at hospital you will be made to walk with a walker or crutches, walk up and down three steps, bend your knee 90 degrees and straighten your knee.

At home you should begin ambulation with a cane as tolerated. Keep your incision clean and dry and watch closely for any signs of infection.

You’ll continue your home exercise program. At home you will work on knee muscle strengthening program.

Your long-term rehabilitation goals are a range of motion from 100-120 degrees of knee flexion, mild or no pain with walking or other functional activities, and independence in all activities of daily living.