Accuracy of the Precision Saw versus the Sagittal Saw during total knee arthroplasty: A randomised clinical trial

The aim of this study was to compare the accuracy of the oscillating tip saw system (Precision Saw=PS) with the more conventional fully oscillating blade system (Sagittal Saw=SS) during computer-assisted total knee arthroplasty (CAS-TKA). A prospective, randomised, controlled trial included 58 consecutive patients who underwent primary CAS-TKA and were randomly assigned in the PS group or the SS group to compare the accuracy of both blades. The primary outcome was the difference between the intended cutting planes and the actual cutting planes in degrees (°) in two planes of both the femur and the tibia. The secondary outcome was total surgery time. Tibia: In the VV-plane no significant differences were registered for the mean absolute deviation (p=0.28). The PS was more accurate in the AP-plane (p=0.03). Femur: The PS showed significantly fewer mean absolute deviations in the VV-plane (p=0.03); however, the SS revealed better accuracy in the FE-plane (p=0.04). The difference in the surgery time between the groups was not statistically significant (p=0.45). Two outliers were measured using the SS, while seven outliers were detected using the PS. The Precision Saw is not proven to be overall more accurate than the Sagittal Saw. Significantly better accuracy was shown with the PS in the two cutting planes, with the exception of one cutting plane that favoured the SS. Greater number of outliers were found using the PS. Level of evidence: II