The meta‐ analysis showed that GB techniques result ed in statistically significant improvements in the restoration of mechanical and rotational alignment and mean Knee Society Scores and Knee Society Function scores two years post‐operatively , but result ed in greater elevation of the position of the joint line .
There is no significant difference in the other radiographic data .
Conclusion This study suggests that GB may provide better radiographic and clinical outcomes than MR when used to determine mechanical rotation in TKAs
Aims There are two techniques widely used to determine the rotational alignment of the components in total knee arthroplasty ( TKA ) ;  gap balancing ( GB ) and measured resection ( MR ) .
Which technique is the best remains controversial .
We aim ed to investigate this in a systematic review and meta‐ analysis .
Rotation in total knee arthroplasty: no difference between patient-specific and conventional instrumentation
Abstract Purpose It was our hypothesis that patient-specific instrumentation ( PSI ) can improve the accuracy of the rotational alignment in TKA based on the concept of the system and on the potential to clearly identify pre-operatively during planning the classical anatomical l and marks that serve as references to set-up the rotation both for the femur and tibia . Material s and methods In this prospect i ve comparative r and omized study , 40 patients ( 20 in each group ) operated in our institution between September 2012 and January 2013 by the 2 senior authors were included . R and omization of patients into one of the two groups was done by the Hospital Informatics Department with the use of a systematic sampling method . All patients received the same cemented high-flex mobile bearing TKA . In the PSI group , implant position was compared to the planed position using previously vali date d dedicated software . The position of the implants ( frontal and sagittal ) was compared in the 2 groups on st and ard X-rays , and the rotational position was analysed on post-operative CT-scan . Results 90 % of the patients add < 2 ° or mm of difference between the planned position of the implants and the obtained position , except for the tibial rotation where the variations were much higher . Mean HKA was 179 ° ( 171–185 ) in the PSI group with 4 outliers ( 2 varus : 171 ° and 172 ° :184 ° and 185 ° ) and 178.3 ° with 2 outliers ( 171 ° and 176 ° ) in the control group . No difference was observed between the two groups concerning the frontal and sagittal position of the implants on the ML and AP X-rays . No significant difference of femoral rotation was observed between the two groups with a mean of 0.4 ° in the PSI group and 0.2 ° in the control group ( p : n.s ) . Mean tibial rotation was 8 ° of internal rotation in the PSI group and 15 ° of internal rotation in the st and ard group ( p : n.s ) . Conclusion Based on our results , we were unable to confirm our hypothesis as PSI can not improve rotation in TKA . More work needs to be done to more clearly define the place of PSI in TKA , to keep on improving the accuracy of the system and to better define the individual targets in TKA in terms of frontal , sagittal and rotational positioning of the implant for each patient . Level of evidence Prospect i ve comparative r and omized study , Level II
The meta‐ analysis showed that GB techniques result ed in statistically significant improvements in the restoration of mechanical and rotational alignment and mean Knee Society Scores and Knee Society Function scores two years post‐operatively , but result ed in greater elevation of the position of the joint line .
There is no significant difference in the other radiographic data .
Conclusion This study suggests that GB may provide better radiographic and clinical outcomes than MR when used to determine mechanical rotation in TKAs
Aims There are two techniques widely used to determine the rotational alignment of the components in total knee arthroplasty ( TKA ) ;  gap balancing ( GB ) and measured resection ( MR ) .
Which technique is the best remains controversial .
We aim ed to investigate this in a systematic review and meta‐ analysis .