Q&A Topic: Patient-Specific Instruments for Total Knee Replacement

David J. Yasgur, MD, FAAOS

Q. Do I need a total knee replacement?

A. You should consider total knee replacement surgery if your severe arthritis of the knee is limiting your walking to the extent that you can’t do the things you need and want to do. Keep in mind that living with arthritis is medically safe. I advise this procedure for patients whose quality of life is significantly affected by the crippling effects of arthritis of the knee.

Q. What is a patient-customized 3-D total knee replacement?

A. This modernized procedure has been in use for about six years. Through advanced 3-D computer modeling technology, we’re able to achieve perfect alignment of the prosthetic knee with your bone structure, and in addition, create patient-customized instruments with which to perform the procedure. These enhancements add up to a far more accurate fit between your body and the prosthetic knee; faster and safer surgery; and your ability to more quickly recover from the surgery and become fully mobile.

Q. What’s involved in patient-customized 3-D knee replacement?

A. Starting six to eight weeks before surgery, you undergo a specialized MRI of the involved knee that includes your hip and ankle. We send this image to the manufacturer, whose engineers convert the MRI to a 3-D computer model of your limb. The model is sent to me as a 3-D software package that shows the implant superimposed over your unique bone structure. This lets me make precise adjustments in size and position while viewing the entire area—even the back of the knee, which is not visible during surgery. The result is perfect alignment and perfect fit of the prosthesis with your bone structure. Alignment directly affects the long-term success of a total knee replacement. Next, using the same digital file, combined with 3-D printing, two specialized surgical instruments are made that contour perfectly to your body—one for the femur (thighbone), one for the tibia (shinbone). These patient-customized instruments permit me to more precisely prepare your knee to receive the prosthesis than ever before possible.

Q. How will I benefit from this advanced procedure? 

A. In many important ways, the 3-D process lets us perform a customized surgical procedure that results in a better fit than ever, so the implant feels far more natural when you move. The procedure itself is done with greater accuracy and in much less time. Reducing surgical time by 20 to 30 minutes makes it safer for the patient—less time under anesthesia, while decreasing the risk of infection, bleeding and blood clots. Post-surgical discomfort and stiffness are also minimized. Perhaps the best news is that you’ll make faster gains in rehab with a knee that fits optimally. 


Learn More About Dr. Yasgur
Director of Quality and Outcomes
Orthopedic and Spine Institute
Northern Westchester Hospital

Read Past Topics from Dr. Yasgur: 
Chronic Knee Pain and Knee Replacement
Hip Replacement Surgeries


‚ÄčNorthern Westchester Hospital is a proud member of Northwell Health.

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