Long-term computer-assisted TKA results show low revision, reoperation rates
Long-term results showed computer-assisted surgery used in 1,048 patients who underwent total knee arthroplasty was associated with average alignment of 1.52° varus and Kaplan-Meier survivorship of 98.34%, a presenter said.
At the Orthopaedic Research Society Annual Meeting, Mary Bayers-Thering, MS, MBA, research manager in the department of orthopedics at Kaleida Health/Buffalo General Medical Center in Buffalo, New York, presented minimum 5-year results after computer-assisted TKA procedures performed between October 2001 and December 2010.
“The reoperation rate in our large consecutive series was 1.38%. Most reoperations done were manipulations under anesthesia. Our revision rate was also low. These results help demonstrate that the use of the computer helps place our components in good position,” she said.
The revision rate for these computer-assisted TKA cases was 1.7%, which, according to the study abstract, is lower than what is reported in the registries and in the literature.
Patients had an average age of 66 years and average BMI of 33.6 kg/m2. About 94% of patients had a diagnosis of primary osteoarthritis and about 94% of patients received a cemented cruciate-retaining prosthesis, according to the abstract.
Concerning alignment, Bayers-Thering said investigators only measured 475 long, standing weight-bearing radiographs, which she noted as one weakness of the study. Nevertheless, “81.3% of the X-rays were either neutral or plus or minus 3°. The average alignment was 1.52° varus,” Bayers-Thering said.
In addition, she said patient knees that exceeded 8° varus or valgus were limited to 2.32% and 0.84%, respectively.
Other study weaknesses included the absence of a control group of patients who underwent TKA without computer assistance and longer follow-up, Bayers-Thering said.
She told Orthopedics Today she was a member of the research team in Buffalo when Kenneth A. Krackow, MD, developed a TKA navigation system. He performed the first case with it in 1997, Bayers-Thering said.
“In 2001, he started using a commercial system he helped develop. Move to 2021, [and] we now have long-term data to support the use of navigation for total knee arthroplasty ... The navigation system allows our surgeons to keep revisions and reoperation rates low while assisting in good component placement. We now know the navigation system is providing better longevity and survivorship for our patients,” she said. – by Susan M. Rapp
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- Mary Bayers-Thering, MS, MBA, can be reached at 100 High St., Buffalo, NY 14203; email: email@example.com.