Non-Cemented Total Knee Replacement
A Non-Cemented Total Knee Replacement is a surgical procedure to replace the knee joint using biological fixation instead of cement to hold the prosthesis in proper position. Fixation is achieved by ingrowth of bone into microscopic pores present on the surface of the implant. The surgeon will use special tools to contour the bone ensuring a snug fit with the prosthesis. This type of prosthesis is also called a press-fit prosthesis.
The goal of the procedure is to stop the knee bones from rubbing against each other causing severe pain and helping people return to activities of normal living with less pain and improved range of motion.
Many surgeons prefer the non-cemented approach to joint replacements because they do not have to worry about breakdown of cement leading to loosening and failure of the prosthesis. Non-cemented total knee replacements are generally indicated for young patients with good quality bone. In older patients with poor quality bone or those with osteoporosis, the biological fixation may not be as strong and therefore they may not be ideal candidates for this procedure.
In preparation for the surgery, you will have to undergo a complete physical examination and evaluation of the knee to record baseline information in terms of pain level, range of motion, and swelling within the knee.
After the administration of anesthesia, the front of the knee will be incised to gain access to the joint. A positioning device known as the cutting guide is then used to ensure cutting of the bone is done at the correct angulation to maintain the functional integrity of the joint. The articulating surface of the patella is then removed. The components of the prosthesis are then press fitted onto the prepared surfaces of the bone. A metal tray is placed on the tibia and held in place with screws. The screws, which are not removed, are needed to hold the implant until sufficient bone ingrowth occurs. A plastic spacer is attached to the metal tray. The spacer prevents friction between the components of the prosthesis. A patellar component is then fit behind the patella and the soft tissues are sewn back in place. The skin incision is then closed with staples.
As with any surgical procedure, there are possible risks which include infection, stiffness, loosening, thrombophlebitis, and anesthetic complications.
Immediately following surgery, physical therapy is encouraged as early knee mobilization improves range of motion, prevents clot formation, and speeds up the healing process. In most cases, you should be able to return home within 2-4 days following surgery. After discharge, you will have to undergo physical therapy to maximize your strength and range of motion.