There was a trend towards a protective effect  with PSCB for the risk of femoral component outliers , but the opposite was observed for the tibial component .
Conclusions This meta- analysis found no evidence that using patient-specific cutting blocks provides superior accuracy to using manual instrumentation during TKA
Purpose Because published studies on the accuracy achieved with patient-specific guides during total knee arthroplasty ( TKA ) contradict each other , this systematic review and meta- analysis sought to compare radiological TKA outcomes when patient-specific cutting blocks ( PSCB ) were used to the outcomes when st and ard manual instrumentation was used .
Component alignment during total knee arthroplasty with use of standard or custom instrumentation: a randomized clinical trial using computed tomography for postoperative alignment measurement.
BACKGROUND Patient-specific femoral and tibial cutting blocks produced with use of data from preoperative computed tomography ( CT ) or magnetic resonance imaging ( MRI ) scans have been employed recently to optimize component alignment in total knee arthroplasty . We report the results of a r and omized controlled trial in which CT scans were used to compare postoperative component alignment between patients treated with custom instruments  and those managed with traditional instruments . METHODS The in-hospital data and early clinical outcomes , including Knee Society scores , were determined in a r and omized clinical trial of forty-seven patients who had undergone a total of forty-eight primary total knee arthroplasties with patient-specific instruments ( twenty-two knees ) or st and ard instruments ( twenty-six knees ) . Orientation of the implants was compared by using three-dimensional CT data . RESULTS No significant differences were found between the study and control groups with respect to any clinical outcome after a minimum of six months of follow-up . The patient-specific tibial cutting block was ab and oned in favor of a st and ard external alignment jig in seven of the twenty-two study knees because of possible malalignment . A detailed analysis of intent-to-treat and per- protocol groups of study and control knees did not show any significant improvement in component alignment , including femoral component rotation in the axial plane , in the patients treated with the custom instruments . The percentage of outliers -- defined as less than -3 ° or more than 3 ° from the correct orientation of the tibial slope -- was significantly higher in the group treated with use of patient-specific blocks than it was in the control group , in both the intent-to-treat ( 32 % versus 8 % , p = 0.032 ) and the per- protocol ( 47 % versus 6 % , p = 0.0008 ) analysis . CONCLUSIONS There were no significant improvements in clinical outcomes or knee component alignment in patients treated with patient-specific cutting blocks as compared with those treated with st and ard instruments . The group treated with patient-specific cutting blocks had a significantly higher prevalence of malalignment in terms of tibial component slope than the knees treated with st and ard instruments
There was a trend towards a protective effect  with PSCB for the risk of femoral component outliers , but the opposite was observed for the tibial component .
Conclusions This meta- analysis found no evidence that using patient-specific cutting blocks provides superior accuracy to using manual instrumentation during TKA
Purpose Because published studies on the accuracy achieved with patient-specific guides during total knee arthroplasty ( TKA ) contradict each other , this systematic review and meta- analysis sought to compare radiological TKA outcomes when patient-specific cutting blocks ( PSCB ) were used to the outcomes when st and ard manual instrumentation was used .