Better accuracy and reproducibility of a new robotically-assisted system for total knee arthroplasty compared to conventional instrumentation: a cadaveric study

Abstract

PurposeRobotically‐assisted total knee arthroplasty (TKA) has been shown to improve alignment and decrease outliers, an important goal in TKA procedures. The purpose of this cadaveric study was to compare the accuracy and reproducibility of a recently introduced TKA robotic system to conventional instrumentation for bone resections. MethodsThis cadaveric study compared 14 robotically‐assisted TKA with 20 conventional TKAs. Four board‐certified high volume arthroplasty surgeons with no prior experience in robotics (except one) performed the procedures with three different implant systems. Angle and level of bone resections obtained from optical navigation or calliper measurements were compared to the intra‐operative plan to determine accuracy. Group comparison was performed using Student t test (mean) and F test (variance), with significance at p < 0.05. ResultsThe robotic group demonstrated statistically more accurate results (p < 0.05) and fewer outliers (p < 0.05) than conventional instrumentation when aiming for neutral alignment. Final limb alignment (HKA) had an accuracy of 0.8° ± 0.6° vs 2.0° ± 1.6°, with 100% vs 75% of cases within 3° and 93% vs 60% within 2°. For the robotically‐assisted knees, the accuracy of bone resection angles was below 0.6° with standard deviations below 0.4°, except for the femur flexion (1.3° ± 1.0°), and below 0.7 mm with standard deviations below 0.7 mm for bone resection levels. ConclusionThis in vitro study has demonstrated that this novel TKA robotic system produces more accurate and more reproducible bone resections than conventional instrumentation. It supports the clinical use of this new robotic system. Level of evidenceCadaveric study, Level V.

The Functionality of a Novel Robotic Surgical Assistant for Total Knee Arthroplasty: A Case Series

“…Klasan et al [32] have recently demonstrated some potential concerns for measurement error associated with CAS landmarks. However, robotic-assisted TKA has already been shown to be more consistent in correcting varus and valgus deformities to a range within 3°of neutral mechanical alignment [33], and recent cadaveric studies 15 Case Reports in Orthopedics conveyed the accuracy of the ROSA total knee application at carrying out bone resection and correcting angles [7,18]. These studies demonstrated an average resection accuracy of <1°for all measures assessed and <1 mm for resection thickness [18].…”

“…Additionally, that study demonstrated planned resections to be within 2 mm of goal in >90% of the specimens reviewed. Further, compared to conventional cases in a cadaveric comparison, this system has the potential to standardize as well as to enhance the reproducibility of TKA through quantitative measures previously unavailable [7].…”

“…This enables the robot to identify the knee in space and allows the surgeon to make real-time intraoperative, patient-specific adjustments according to the patient's unique anatomy. The robotic arm assists in positioning the cutting jigs in the planned cutting plane and allows for accuracy down to 0.5 mm [7,18].…”

“…The patient-reported dissatisfaction rate for primary total knee arthroplasty (TKA) is approximately 10% to 20% [1][2][3]. However, the introduction of robotic technology has the potential to change the narrative in TKA outcomes by allowing for greater precision in implant positioning compared to manual instrumentation [4][5][6][7][8]. Further, recent studies have suggested robotic-assisted TKA (RATKA) patients experience faster short-term recovery than conventional patients [9,10].…”

“…With this novel robotic system, the ability to perform submillimeter bone resections allows the surgeon to balance the knee through boney resections versus soft tissue releases [7,18]. This also allows the surgeon to adjust both distal femoral and proximal tibial cuts appropriately, to help minimize the risk of patella baja, thus keeping the joint height appropriate.…”