New Technology is ‘Global Positioning’ for Knee Replacement

A computer guidance system is providing orthopaedic surgeons with a remarkable new tool for reducing alignment problems in knee surgery. Bernard Stulberg, M.D., director of the Center for Joint Reconstruction at the Cleveland Orthopaedic and Spine Hospital at Lutheran, is the first surgeon in Northeast Ohio to begin using this leading-edge knee replacement innovation.

This is a very precise tool that allows us to place the knee with increased accuracy, says Stulberg, who has performed 15 successful surgeries using the Stryker Navigation System since July. Potential benefits of the system include improved accuracy to within one degree of desired alignment, improved predictability, joint stability, fewer complications and shorter hospital stays.

Most importantly, this system ensures the best position for the prosthesis. With better positioning, the knee can last longer and perform better, meaning it’s unlikely the patient will have to undergo the procedure again within the next 15 years, says Stulberg.

Proper limb alignment of the patient’s knee, hip and ankle is critical to long-term successful function of the knee prosthesis. Due to variations in patients’ individual anatomies, however, traditional surgical instruments based on average shapes and angles can result in less-than-ideal alignment and stability, leading to diminished success.

The Stryker Navigation System provides the information necessary for precise alignment. This new alignment technology is like a global positioning system for the knee, says Stulberg. Our goal is to restore the natural center of rotation. The navigational system provides surgeons with a much better breadth of information about the patient’s knee before the prosthesis is placed.

This data enables us to make real-time adjustments to correctly position and optimally orient the prosthesis.

Used prior to total knee replacement surgery, the Stryker Navigation System allows surgeons to have a complete understanding of the conditions within the patient’s knee before any bone is cut. The device assists the surgeon in the placement of instruments, the location and depth of bone cuts, and placement of implant components before surgery.

The navigation system consists of a smart camera that provides two-way communication between the instruments that comprise the navigation system, which include a computer and monitor with special software, and minimally invasive wireless pointers and trackers that incorporate infrared emitters. Each instrument stores its own calibration data and tests itself each time it is brought into the operation field. These special features increase the reliability of the system.

The procedure begins with the surgeon inserting two tracking pins into the patient’s knee, one above and one below the knee. Then a special tracking device, positioned to face the camera, is mounted on each of the pins. Using the pointer, the surgeon touches various locations in the area that’s being operated on. The system’s software collects this information, maps it and graphically shows it on the screen. As is standard procedure with total knee replacement operations, the surgeon physically manipulates the patient’s leg, rotating it in different directions and angles to locate the knee’s natural center of rotation. As the surgeon is doing this, the rotation information appears on the computer monitor as two-dimensional graphics in real time. Coupled with images of key anatomical points and areas of bone deficiency and soft tissue, the surgeon is able to make very precise bone resections and then place the prosthesis with great accuracy. For more information, on the latest GPS News see hand held gps.

Author Notes:

Rudy Douval contributes and publishes news editorial to http://www.handheld-gps-reviews.com.  A wealth of information about Global Positioning Systems for commercial or personal use.