A national registry study found robotic-assisted total knee arthroplasty was not associated with lower revision rates or different failure patterns overall compared with conventional total knee arthroplasty, while surgeons with higher baseline revision rates had increased late revision hazard after adopting the technology.
Researchers reported that robotic-assisted total knee arthroplasty did not reduce all-cause revision rates at the grouped cohort level when compared with non–robotic-assisted procedures performed by the same surgeons after robotic adoption. However, high-revision-rate surgeons showed a shift in the timing of revision risk after adopting the technology.
The Level III observational registry study, led by Wayne Hoskins, PhD, of The University of Melbourne, used data from the Australian Orthopaedic Association National Joint Replacement Registry, which captures more than 98% of arthroplasty procedures in Australia. Researchers screened total knee arthroplasties performed for osteoarthritis from September 1999 to December 2023 and included 178 surgeons who performed 85,075 eligible procedures — a mix of robotic-assisted and non–robotic-assisted procedures — after beginning robotic-assisted total knee arthroplasty.
Surgeons were grouped according to their 2-year cumulative percent revision rates before adopting robotic assistance: low revision rate, defined as 1% or less; middle revision rate, defined as more than 1% to 2.5%; and high revision rate, defined as 2.5% or greater. Preadoption data from 1999 to 2023 were used only to classify surgeons, while comparative analyses were limited to procedures performed from 2016 onward, after each surgeon’s individual transition to robotic assistance, with follow-up through December 31, 2023.
The primary outcome was all-cause cumulative percent revision. Secondary outcomes included changes in revision for infection, implant loosening, and instability. Analyses were adjusted for age, sex, American Society of Anesthesiologists score, body mass index, patellar resurfacing, year of surgery, fixation, bearing surface, and insert type.
Among low- and middle-revision-rate surgeons, robotic-assisted total knee arthroplasty was not associated with lower revision rates compared with conventional total knee arthroplasty. Among high-revision-rate surgeons, robotic-assisted procedures were associated with lower revision risk in the first 3 months but more than twice the hazard of revision after 9 months. The researchers reported no statistically significant difference between 3 and 9 months, and the higher late revision hazard was not attributable to a single failure mode.
The researchers found that failure patterns were similar with and without robotic assistance. Revision rates for infection, implant loosening, and instability did not change in any surgeon cohort after robotic adoption. The researchers also found that surgeons more frequently used cementless fixation, highly cross-linked polyethylene, and patellar resurfacing after adopting robotic-assisted total knee arthroplasty, while use of posterior-stabilized bearings decreased.
The researchers noted that the findings do not rule out potential benefits of robotic-assisted total knee arthroplasty beyond revision risk. The registry analysis did not assess patient-reported outcomes, functional recovery, pain, satisfaction, or other performance measures that may be relevant to patients and physicians. Follow-up was also limited, with mean follow-up of approximately 2.4 years and maximum follow-up of 7 years.
The researchers noted several other limitations, including potential selection bias in which cases received robotic assistance, lack of data on surgeon training or learning curves, and inability to assess alignment strategy or case complexity. All robotic systems were grouped together, although systems may differ in workflow, alignment philosophy, learning curve, and complications.
The findings were consistent with prior registry-based research cited by the researchers, including American Joint Replacement Registry analyses that found no reduction in early revision rates with robotic-assisted total knee arthroplasty and a Medicare-based analysis that found no improvement in 5-year cumulative percent revision, mechanical loosening, or other mechanical complications. However, the researchers noted that the American Joint Replacement Registry also found increased odds of revision for instability with robotic assistance and a trend toward increased odds of mechanical loosening with cementless total knee arthroplasty, partially paralleling the adverse late-revision signal observed in the current study’s high-revision-rate cohort.
“Although the benefits of RA-TKA may potentially extend beyond revision rates, with the data currently available, the exact role of RA-TKA remains unknown,” wrote Dr. Hoskins and colleagues.
Disclosures forms are available with the published article.
Source: JBJS Open Access