The three-year survivorship of robotically assisted versus non-robotically assisted unicompartmental knee arthroplasty

Abstract

Aim There has been a significant reduction in unicompartmental knee arthroplasty (UKA) procedures recorded in Australia. This follows several national joint registry studies documenting high UKA revision rates when compared to total knee arthroplasty (TKA). With the recent introduction of robotically assisted UKA procedures, it is hoped that outcomes improve. This study examines the cumulative revision rate of UKA procedures implanted with a newly introduced robotic system and compares the results to one of the best performing non-robotically assisted UKA prostheses, as well as all other non-robotically assisted UKA procedures. Methods Data from the Australian Orthopaedic Association National Joint Arthroplasty Registry (AOANJRR) for all UKA procedures performed for osteoarthritis (OA) between 2015 and 2018 were analyzed. Procedures using the Restoris MCK UKA prosthesis implanted using the Mako Robotic-Arm Assisted System were compared to non-robotically assisted Zimmer Unicompartmental High Flex Knee System (ZUK) UKA, a commonly used UKA with previously reported good outcomes and to all other non-robotically assisted UKA procedures using Cox proportional hazard ratios (HRs) and Kaplan-Meier estimates of survivorship. Results There was no difference in the rate of revision when the Mako-assisted Restoris UKA was compared to the ZUK UKA (zero to nine months: HR 1.14 (95% CI 0.71 to 1.83; p = 0.596) vs nine months and over: HR 0.66 (95% CI 0.42 to 1.02; p = 0.058)). The Mako-assisted Restoris had a significantly lower overall revision rate compared to the other types of non-robotically assisted procedures (HR 0.58 (95% confidence interval (CI) 0.42 to 0.79); p < 0.001) at three years. Revision for aseptic loosening was lower for the Mako-assisted Restoris compared to all other non-robotically assisted UKA (entire period: HR 0.34 (95% CI 0.17 to 0.65); p = 0.001), but not the ZUK prosthesis. However, revision for infection was significantly higher for the Mako-assisted Restoris compared to the two comparator groups (ZUK: entire period: HR 2.91 (95% CI 1.22 to 6.98; p = 0.016); other non-robotically assisted UKA: zero to three months: HR 5.57 (95% CI 2.17 to 14.31; p < 0.001)). Conclusion This study reports comparable short-term survivorship for the Mako robotically assisted UKA compared to the ZUK UKA and improved survivorship compared to all other non-robotic UKA. These results justify the continued use and investigation of this procedure. However, the higher rate of early revision for infection for robotically assisted UKA requires further investigation. Cite this article: Bone Joint J 2020;102-B(3):319–328

Comparison of robotic‐assisted versus conventional unicompartmental knee arthroplasty for the treatment of single compartment knee osteoarthritis: A meta‐analysis

“…Several factors such as building additional skin incisions, inserting biocritical registration pins, could increase surgery time to a certain extent. The main concern is that the increased operation time may be a potential risk factor for complications 39 . But there is currently no convincing evidence that the robotic group has higher rate of complications, our research also found no significant difference between the two groups.…”

“…Comparing 246 robotic‐assisted UKA and 492 conventional UKA patients from database, Cool et al found the robotic group had a significant lower rate of revision 38 . By analysing the time difference data from the Australian Orthopaedic Association National Joint Arthroplasty Registry, Mart also found the nine months postoperative overall repair rate of the robot system (Mako) was significantly lower than that of the non‐robotically assisted technology (3068 robotically assisted and 6468 non‐robotically assisted UKA procedures) 39 . Comparing the 2%–5.7% of TKA recipients experience failure that necessitate revision surgery within 5 years and 13.3% conventional UKA, robotic UKA is seen as an ideal method to reduce the rate of revision 38,39 …”

Superior component position during robotic-assisted Oxford unicompartmental knee arthroplasty (UKA) compared with conventional technique: A 5-year follow-up study

“…UKA survivorship is considered to be determined by limb alignment [8,10,15,16]. Nevertheless, it still remains controversial in the standard of correct limb alignment following UKA.…”

“…Robotically assisted UKA has been introduced, which provides accurate feedback of the relative position of the cutting jigs and the host bones during operation. A number of reports have demonstrated that implantation could be more accurate in robotically assisted UKA as compared with conventional technique on a consistent basis [10][11][12]. Apart from that, robotically assisted operation can be more reproducible, which is of great benefit because the technics of the procedure are challenging in UKA surgery.…”

“…Although several reports have already illustrated the short-term outcomes of robotic-assisted UKA [10,12], there are few studies containing mid-term results [13,14]. Unfortunately, to our knowledge, no prospective randomized study comparing component position or clinical outcomes of the robotic-assisted UKA with conventional UKA at a mid-term follow-up is available.…”