There were no significant differences regarding the biomechanical axis or frontal femoral and individual tibial component alignment .
Conclusion This systematic review and meta- analysis demonstrate that alignment with MRI-based PSI is at least as good as , if not better than , that with CT-based PSI .
Purpose Patient-specific instruments ( PSIs ) are already in relatively common use , and their post-operative radiographic results are equal to those for total knee arthroplasty ( TKA ) with conventional instrumentation .
PSI use requires a preoperative MRI scan , CT scan , or a combination of MRI and a long-leg st and ing radiograph .
However , there is no consensus as to which of these modalities , MRI or CT , is the preferred imaging modality when performing TKA with PSIs .
Comparison between patient-specific instruments and conventional instruments and computer navigation in total knee arthroplasty: a randomized controlled trial
Abstract Purpose The current study investigated the accuracy in achieving proper lower limb alignment and individual component positions after total knee arthroplasty ( TKA ) with 3 different instrumentation techniques . It was hypothesized that patient-specific instruments ( PSI ) would achieve more accurate lower limb alignment and component positions compared to conventional instruments ( CON ) . Methods Ninety knees in 81 patients were r and omized in 1:1:1 ratio into  CON , computer navigation ( NAV )  and PSI  groups to receive TKA . The surgical routines were st and ardized . The lower limb mechanical axis and individual component positions were assessed on st and ard radiographs . Tourniquet time , operation time and patients ’ functional scores were documented . Results Conventional instruments and PSI were more likely to result in an excessively flexed femoral component ( p = 0.001 ) compared to NAV . Number of outliers in postoperative lower limb alignment , and other components positions in the coronal and sagittal plane showed no statistically significant difference . The mean tourniquet time and operation time was significantly shorter in CON and PSI groups than NAV group ( p < 0.001 ) . Four early complications occurred in the PSI group ( p = 0.015 ) . At 3-month follow-up , there was no difference in terms of the knee range of motion and patients ’ function among the 3 groups . Conclusion No significant radiological and clinical benefit could be demonstrated in using PSI over CON or NAV in TKA . Routine use of PSI is not recommended because of the extra cost and waiting time . Level of evidence
There were no significant differences regarding the biomechanical axis or frontal femoral and individual tibial component alignment .
Conclusion This systematic review and meta- analysis demonstrate that alignment with MRI-based PSI is at least as good as , if not better than , that with CT-based PSI .
Purpose Patient-specific instruments ( PSIs ) are already in relatively common use , and their post-operative radiographic results are equal to those for total knee arthroplasty ( TKA ) with conventional instrumentation .
PSI use requires a preoperative MRI scan , CT scan , or a combination of MRI and a long-leg st and ing radiograph .
However , there is no consensus as to which of these modalities , MRI or CT , is the preferred imaging modality when performing TKA with PSIs .