Complications and Learning Curve Associated with an Imageless Burr-Based (CORI) Robotic-Assisted Total Knee Arthroplasty System: Results from First 500 Cases

Abstract

Background: The use of robotic-assisted total knee arthroplasty (RA-TKA) is gaining traction. There is evidence to suggest that RA-TKA can help to optimize the precision and accuracy of implant positioning and that there may be protective effects on surrounding bony and soft tissues. Yet, there are important differences between the various RA-TKA systems currently on the market. One such newly introduced RA-TKA system uses imageless technology and performs bony cuts with the use of a burr-based device. The learning curve and complications unique to this system have yet to be assessed.

Methods: We evaluated 500 consecutive RA-TKA cases using a newly developed burr-based and imageless system which were done by a single surgeon between the months of October 2021 and February 2023. Operative times were recorded and compared to the previous 150 conventional TKA cases allowing for the learning curve to be calculated using the CUSUM method. Intraoperative and postoperative complications were categorically profiled.

Results: The learning curve of this RA-TKA system was found to be 6 cases. Intraoperative complications included unintended bony over resection (n = 3), soft tissue injury (n = 2), and robotic system hardware (n = 2) or software (n = 2) malfunction. Postoperative complications consisted of superficial pin site infection (n = 1) and periprosthetic fracture near the pin sites (n = 1). There were no identified cases of prosthetic joint infection, instability events, or wound complications.

Conclusions: The learning curve and the complication profile of a newly introduced imageless and burr-based RA-TKA system were described. This information serves to guide surgeons in adopting this technology and can counsel them regarding the potential pitfalls and challenges associated with its integration into practice. The work sheds light on the complexity and learning curve of the recently released imageless burr-based RA-TKA system. This important information is intended to help surgeons accept this cutting-edge technology by providing advice on any errors and difficulties that can occur when integrating it into clinical practice. This information can help surgeons navigate the complexities of integrating this new burr-based robotic technology into knee replacement procedures, enabling them to make well-informed decisions and receive guidance.

Keywords: CORI; Complications; Learning curve; Robotic knee replacement; Safety.

Fig. 1

a Learning curve. b Illustration of surgical time in entire 500 cases and average time in first and last 20 cases

Fig. 2

Over-resection by robotic arm. a Over-resection possibly due to osteoporotic bone wherein the pressure of the operator on weak bone may cause resection beyond the intended depth. b Here, the over-resection is likely secondary to malfunctioning in the software or a calibration error causing the drill over-resect bone. Note more uniformly red areas denoting device mis-calibration. c and d Mis-calibration on the tibial side

Fig. 3

a Software malfunctioning mid procedure being reported by the system b A key performance characteristic (KPC) analysis done later evaluates various elements of possible hardware and software malfunction

Fig. 4

Periprosthetic fracture at pin tract on the femoral side reported 3 weeks post operation. Patient later underwent periprosthetic fracture fixation using a bridging locking plate. Patient recovered and fracture healed 3-month post fixation