We did not find any differences between PSI and SI with respect to any other parameters .
Conclusions PSI  has advantages in axial alignment of the femoral component , operative time , and perioperative blood loss relative to SI .
No significant differences were found between PSI and SI with respect to alignment of the remaining components , number of outliers , or length of hospital stay .
Purpose The purpose of the present study was to compare patient-specific instrumentation ( PSI ) with st and ard instrumentation ( SI ) in patients undergoing total knee arthroplasty ( TKA ) .
PSI is hypothesized to have advantages with respect to component alignment ; number of outliers ( defined as alignment > 3 ° from the target alignment ) ; operative time ; perioperative blood loss ; and length of hospital stay .
This new surgical technique is expected to exhibit superior performance .
Custom-fit minimally invasive total knee arthroplasty: effect on blood loss and early clinical outcomes
Purpose Recently , new custom-fit pin guides in total knee arthroplasty ( TKA ) have been introduced . Use of these guides may reduce operating time . Use of the guides combined with the absence of intramedullary alignment jigs may lead to reduced blood loss and improved early outcomes . Our aim was to evaluate blood loss and early clinical outcomes in patients undergoing minimally invasive TKA using custom-fit magnetic resonance imaging (MRI)–based pin guides . Methods A prospect i ve study in 80 patients was carried out . Patients were divided r and omly into 2 equal groups . In one group , intramedullary alignment jigs were used . In the second group , custom-fit MRI-based pin guides were used . All patients received the same cemented posterior-stabilized implant through a mini-midvastus approach . The volume in the drain bottles was recorded after 48 h. Hb loss was estimated by subtracting the postoperative from the preoperative Hb level . Transfusion requirements and surgical time were recorded . Outcome measures were Knee Society Scores ( KSS ) , knee flexion , knee swelling and pain . Results There was lower mean drainage of blood in the custom-fit group ( 391 ml vs. 603 ml ; p < 0.0001 ) . There was no difference in estimated loss of Hb ( 3.6 g/dl vs. 4.1 g/dl ; n.s . ) and in transfusion requirements ( 7.5 % vs. 10 % ; n.s . ) . Surgical time was reduced in the custom-fit group ( 12 min less ; p = 0.001 ) . KSS measured at week 2 , 6 and 12 showed no significant difference between groups . Knee flexion measured on days 7 , 10 and at week 6 , 12 and knee swelling and pain measured on days 1 , 3 , 10 and at week 6 , 12 showed no significant difference between groups . Conclusions Using custom-fit pin guides reduces blood drainage , but not the estimated Hb loss in minimally invasive TKA and does not affect transfusion rate . Surgical time is reduced . There is no effect on the early clinical outcomes .Level of evidence Therapeutic study , Level
We did not find any differences between PSI and SI with respect to any other parameters .
Conclusions PSI  has advantages in axial alignment of the femoral component , operative time , and perioperative blood loss relative to SI .
No significant differences were found between PSI and SI with respect to alignment of the remaining components , number of outliers , or length of hospital stay .
Purpose The purpose of the present study was to compare patient-specific instrumentation ( PSI ) with st and ard instrumentation ( SI ) in patients undergoing total knee arthroplasty ( TKA ) .
PSI is hypothesized to have advantages with respect to component alignment ; number of outliers ( defined as alignment > 3 ° from the target alignment ) ; operative time ; perioperative blood loss ; and length of hospital stay .
This new surgical technique is expected to exhibit superior performance .