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Computer-Assisted Total Knee Replacement

Kenneth Krackow, MD
By adapting motion-analysis equipment, Kenneth Krackow, MD, enabled knee surgeons to operate with unprecedented precision.

Total knee replacement procedures have been performed since the 1960s and significantly restore function and reduce pain for most patients.

Despite this success, surgeons in years past were dissatisfied with the prosthetics’ variable life span, which primarily depended on two factors: the wear and tear the knee was exposed to, and the precision with which the replacement components were initially fitted by surgeons, who had no option but to rely on the “naked eye” to make their calculations.

In the mid-1990s, UB professor of orthopedic surgery Kenneth Krackow, MD, an internationally renowned expert in lower-joint reconstruction and replacement, developed a technology that circumvented this reliance.

“Many surgeons, myself included, were making judgments that were not as precise as they could be because we had no specific data on which to base those decisions,” recalls Krakow, who also serves as head of orthopedic surgery at Kaleida Health.

Krackow had the idea to take existing motion-analysis equipment, such as that being used in the aircraft and motion picture industries, and adapt it to improve the then-standard total-knee replacement procedure.

After obtaining the equipment, he worked with UB orthopaedic research fellows in his lab to make software and hardware adaptations to it.

Krackow’s graduate education in mathematics and his interest in computer science and inventing all naturally coalesced to drive his research.

“One of the reasons I chose orthopaedic surgery as a field was my expectation that orthopedics was a discipline in which I could invent,” he notes.

By 1997, a prototype was ready for the operating room and Krackow performed the first computer-assisted total knee replacement. In an article he and his group published in the journal Orthopaedics, they described how the new system enabled surgeons to make precise decisions on the alignment and orientation of instruments, the location and depth of bone cuts and the placement of knee implant components.

A few years later, Krackow partnered with the medical products manufacturer Stryker Company. The company further refined the equipment, and they now market it as the Stryker Navigation System: Knee Module.

In October 2001, Krackow performed the first computer-assisted total knee replacement outside of Europe using the Stryker Navigation System and the first FDA-approved total-knee replacement procedure in this country. Since then, he has introduced the procedure to orthopedic surgeons worldwide, both in person and via satellite broadcasts from Buffalo General Hospital.