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A study recently reported at the 2024 Annual Meeting of the American Academy of Orthopaedic Surgeons suggests that in the short term, revision rates are similar with robotic-assisted and convention total knee arthroplasty (TKA).

The study authors also found that the odds of revision due to infection or mechanical loosening were not significantly different between the 2 techniques.

“A lot of single surgeon studies show there is improved precision with robotic-assisted TKA,” said Lucas E. Nikkel, MD, assistant professor of orthopaedic surgery, Johns Hopkins Medicine. “Some studies suggest there may be improved early recovery or less damage to soft tissue.

“One of the challenges with evaluating this is that many previous studies had significant financial conflicts of interest with the authors. We wanted to evaluate these questions using a registry study to eliminate the potential confounding factors to understand if there is a difference when this technology is applied to a surgery.”

Study Cohort

Using the American Joint Replacement Registry (AJRR), the researchers identified patients who had undergone cementless TKA with and without robotic assistance between January 2017 and March 2020 and who had been followed for a minimum of 2 years. The researchers then focused solely on data from patients aged 65 years and older due to the data linkage between AJRR and inpatient/outpatient Medicare claims data. This allowed the researchers to track patients if they switched hospitals.

The primary and secondary outcomes of interest were 2-year all-cause odds of revision for cementless TKA with versus without robotic assistance and 2 -year odds of the specific indication for revision surgery.

A total of 9220 cementless TKAs were identified: 4130 performed with robotic assistance and 5090 performed without robotic assistance.

Study Findings

The researchers used a multivariable, mixed-effects, logistic regression model to compare data on the 2 groups. After controlling for cofounders, they reported that:

• The odds of all-cause revision at 2 years following surgery were similar between the conventional and robotic-assisted cohorts (odds ratio 0.8, 95% CI 0.05 to 1.3; P=0.4)
• The odds of revision due to infection were similar between the 2 groups (OR 1.47 95% CI 0.8 to 2.6; P=0.19)
• Mechanical loosing was not significantly different between the cohorts (OR 3.2, 95% CI 0.8 to 12; P=0.09)

“Utilizing patients over age 65, we expected them to have higher failure rates as the potential for biologic fixation may be slightly lower,” said Dr. Nikkel. “We found there was no significant differences in the risk of needing another operation within the first two years after surgery with a robotic-assisted or manual technique.

“This is significant in this population as the likelihood of an early failure is pretty much the same whether robotic assistance is used or not.”

The researchers noted there were several limitations of the study, including the fact that national registries are reliant on the accuracy of data submitted, with 60% of AJRR TKAs not reporting if robotic assistance was used or not, and that younger patients were excluded from this study.

Source

Kirchner GJ, Jimenez E, Mullen K, Nikkel LE. Effect of Robotic Assistance on Early Revisions and Aseptic Loosening in Cementless Total Knee Arthroplasty: An Analysis of the American Joint Replacement Registry (paper 741). Presented at the American Academy of Orthopaedic Surgeons’ 2024 Annual Meeting, February 12-16, 2024, in San Francisco, California.