We found that there was no significant benefit from using PS instrumentation in primary knee arthroplasty to aid in the positioning of either the tibial or femoral components .
Furthermore sagittal plane tibial component positioning was worse in the PS than the traditional ST group .
Our results suggest that at present PS instrumentation is not superior to ST instrumentation in primary total knee arthroplasty .
OBJECTIVE The aim of this study was to review the radiological alignment outcomes of patient Specific ( PS ) cutting blocks and St and ard Instrumentation in Primary Total Knee Arthroplasty .
METHODS We hypothesized that the use of PS techniques would significantly improve sagittal , coronal and rotational alignment of the prosthesis on short term .
A prospective randomised controlled study of patient-specific cutting guides compared with conventional instrumentation in total knee replacement.
Patient-specific cutting guides ( PSCGs ) are design ed to improve the accuracy of alignment of total knee replacement ( TKR ) . We compared the accuracy of limb alignment and component positioning after  TKR  performed using PSCGs or conventional instrumentation . A total of 80 patients were r and omised to undergo TKR with either of the different forms of instrumentation , and radiological outcomes and peri-operative factors such as operating time were assessed . No significant difference was observed between the groups in terms of tibiofemoral angle or femoral component alignment . Although the tibial component in the PSCGs group was measurably closer to neutral alignment than in the conventional group , the size of the difference was very small ( 89.8 ° ( sd 1.2 ) vs 90.5 ° ( sd 1.6 ) ; p = 0.030 ) . This new technology slightly shortened the bone-cutting time by a mean of 3.6 minutes ( p < 0.001 ) and the operating time by a mean 5.1 minutes ( p = 0.019 ) , without tangible differences in post-operative blood loss ( p = 0.528 ) or need for blood transfusion ( p = 0.789 ) . This study demonstrated that both PSCGs and conventional instrumentation  restore limb alignment and place the components with the similar accuracy . The minimal advantages of PSCGs in terms of consistency of alignment or operative time are unlikely to be clinical ly relevant
We found that there was no significant benefit from using PS instrumentation in primary knee arthroplasty to aid in the positioning of either the tibial or femoral components .
Furthermore sagittal plane tibial component positioning was worse in the PS than the traditional ST group .
Our results suggest that at present PS instrumentation is not superior to ST instrumentation in primary total knee arthroplasty .
OBJECTIVE The aim of this study was to review the radiological alignment outcomes of patient Specific ( PS ) cutting blocks and St and ard Instrumentation in Primary Total Knee Arthroplasty .
METHODS We hypothesized that the use of PS techniques would significantly improve sagittal , coronal and rotational alignment of the prosthesis on short term .