Conference Coverage

Robotic and manual total knee arthroplasty found at least comparable


FROM aaos 2020

When results in a series of robotic-assisted total knee arthroplasties (TKA) were compared with a series of arthroplasties performed manually by the same surgeon, results were comparable even though the robotic procedures included a learning phase. The results of the study were reported in an abstract scheduled for release at the annual meeting of the American Academy of Orthopaedic Surgeons. The meeting was canceled because of COVID-19.

“Robotics appears to level the playing field for those who are less experienced, so that robotic total knee arthroplasty might be particularly well suited to low-volume surgeons,” reported Sridhar R. Rachala, MD, assistant professor of orthopaedic surgery, University of Buffalo (N.Y.).

In this retrospective cohort study, radiographic and clinical outcomes were evaluated in 164 total knee arthroplasties performed manually over an 8-month period and compared with 300 procedures performed robotically by the same experienced surgeon over the subsequent 15-month period.

There were no significant differences between patient groups for mean age or body mass index. Dr. Rachala, who performed both sets of procedures, reported inherent differences in technique. Specifically, the mechanical alignment was planned for a traditional neutral mechanical axis, while the robotic procedures were planned in kinematic alignment.

When evaluated at 1 year, the mean KOOS JR (Knee Injury and Osteoarthritis Outcome for Joint Replacement) scores were not significantly different for the robotic and manually performed procedures (76.0 vs. 73.9; P = .54). There were also no differences in the final extension (P = .64) or flexion (P = .59).

However, the difference in mean length of stay (2.0 vs. 2.4 days; P = .0002) favored the robotic approach, and the higher proportion of patients discharged to home after robotic surgery (73% vs. 66%; P = .11) suggested a favorable trend. Planned and postoperative alignment was within two degrees for both groups and not significantly different.

“The robotic series were at a disadvantage because it included cases that I performed when first switching to this approach,” reported Dr. Rachala in an interview.

Although a growing number of total hip arthroplasties are performed robotically, there have not so far been many comparisons of clinical outcomes among surgeons experienced with both approaches, according to Dr. Rachala. Acknowledging that a single-surgeon experience could be considered a limitation of this series, Dr. Rachala also considers it a potential strength. Dr. Rachala was highly experienced with manually instrumented total knee arthroplasty when he switched.

“Positioning and alignment are not just more accurate but easier to perform with robotic assistance,” he said, explaining why this approach is likely to offer a particular advantage to surgeons who perform these types of arthroplasties at low volume. He noted that robotic programming helps prevent errors and adopt alternative more personalized alignments.

Although Dr. Rachala acknowledged that long-term and controlled studies are needed, his experience suggests that robotic-assisted procedures are emerging as a viable alternative with advantages for the surgeon as well as the patient.

The principle that robotic assistance can add consistency to total joint arthroplasty is valid, according to Gwo-Chin Lee, MD, an associate professor of orthopaedic surgery, University of Pennsylvania, Philadelphia. “Robotic-assisted arthroplasty improves the accuracy and consistency of the procedure, which can potentially reduce the likelihood of failure. In knees, it is proven to be valuable in unicompartmental replacements in which results are correlated to a surgeon’s surgical volume. It has an equalizing effect relative to a surgeon with more extensive experience,” Dr. Lee said.

The senior author of a recent systematic review and meta-analysis of robotic-assisted unicompartmental knee arthroplasty (J Knee Surg. 2020 Jan 30; doi: 10.1055/s-0040-1701455), Dr. Lee said, “While the impact of robotics on other metrics including patient satisfaction and early recovery continues to be debated among surgeons who specialize in total knee arthroplasties, the technology can aid surgeons in component position, sizing, and ligament balance, particularly for the lower-volume surgeons and ultimately lead to more predictable outcomes.”

Dr. Rachala reports a financial relationship with Avanos and Stryker.

SOURCE: Rachala S et al. AAOS 2020. Abstract P0091.

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