Palm-sized surgical navigation system enabled by Analog Devices’ MEMS motion sensing technology

NORWOOD, USA: Analog Devices Inc. announced that OrthAlign Inc. has selected ADI’s high-performance iMEMS inertial motion sensing technology to enable its new portable surgical navigation system that guides femoral alignment during knee surgery.

The KneeAlign 2 System, which also provides precise tibial alignment, uses an ADI iSensor digital IMU (inertial measurement unit) to allow an orthopedic surgeon to quickly determine the center of rotation of a patient’s femur and calculate the precise angles to cut the bone in knee replacement surgery.

The compact KneeAlign 2 System combines the alignment precision of large, computer-assisted surgical equipment with the simplicity of conventional instrumentation. The palm-sized KneeAlign unit and its associated cutting instrumentation are compatible with all implant systems used in TKA (total knee arthroplasty), a surgical procedure in which pieces of the knee are replaced with artificial parts.

“Successful TKA surgery depends on accurate knee alignment,” said Patrick O’Doherty, VP, Healthcare Group, Analog Devices. “By using an ADI iSensor IMU, the KneeAlign 2 provides alignment precision comparable to the larger, significantly more expensive camera-based navigation systems, which are shown to result in knee replacement alignment outcomes of 91 percent accuracy compared to 68 percent accuracy using conventional mechanical surgery. As the patient’s knee is put through a full sweep of motion, the surgeon relies on the positioning and dynamics captured by the IMU to quickly determine the precise orientation of the femoral cutting block.”

According to figures available from the Agency for Healthcare Research and Quality, approximately 675,000 Americans underwent knee replacement surgery in 2009. And it is estimated that this procedure will be performed on 3.5 million in 2030. Currently, an estimated 30 percent of all TKA procedures result in poor implant alignment.

“Analog Devices’ iSensor IMU played an instrumental role in making the design of the KneeAlign 2 System possible,” said Darius Kharabi, OrthAlign’s VP of Corporate Development. “This month we completed our limited use release of approximately 50 TKA surgeries using the KneeAlign 2 for both femoral and tibial navigation in highly regarded knee surgery centers across the United States, and the results are extremely encouraging. We plan to launch the KneeAlign 2 System in the first quarter of 2012, while continuing clinical studies at the Hospital for Special Surgery in New York, Scripps Green Hospital in California and other centers of excellence.”