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

Purpose

Robotically-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.

Methods

This 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.

Results

The 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.

Conclusion

This 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 evidence

Cadaveric study, Level V.