human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: This study develops and vali date s a novel patient-specific navigational template for total knee arthroplasty ( TKA ) . A total of 70 patients who underwent TKA were r and omized and divided into conventional method group and navigational template group . In the navigational template group , the patient-specific navigational templates were design ed and used intraoperatively to assist 35 patients with knee arthroplasty . Information on operation time and blood loss was recorded . After surgery , the positions of the prosthesis were evaluated using CT scan and X-rays . Analysis showed significant differences in errors between the two techniques . In addition , mean operation time and mean blood loss were statistically and significantly lower in the navigational template group than in the conventional group . Overall , the navigational template method showed a high degree of accuracy and efficacy Purpose To compare the femoral and tibial components rotational alignment in total knee arthroplasty ( TKA ) performed either with conventional or with patient-specific instrumentation . Methods Forty-five patients underwent primary TKA and were prospect ively r and omized into two groups : 22 patients into the conventional instrumentation group ( group A ) and 23 patients into the Signature ™ patient-specific instrumentation group ( group B ) . All patients underwent computed tomography of the operated knee in the first week after surgery to measure  the components rotation . Results The femoral component rotation was 0.0 ° ( −0.25 , 1.0 ) in group A , and 0.0 ° ( 0.0 , 1.0 ) in group B. The tibial component rotation was −16.0 ° ( −18.5 , 11.8 ) in group A , and −16.0 ° ( −19.0 , −14.0 ) in group B. There were no significant differences between the two groups in tibial and femoral components rotation . The difference between the tibial component rotation and the neutral tibial rotation was similar in both groups [ 2.0 ° ( −0.5 , 6.3 ) in group A and 2.0 ° ( −1.0 , 4.0 ) in group B ] , but the dispersion around the median was different between the two groups . The amplitude of the difference between tibial rotation and neutral position was 27 ° ( −13 , 14 ) in group A and 9 ° ( −3 , 6 ) in group B. Conclusions There is a smaller chance of internal malrotation of the tibial component with the Signature ™ patient-specific instrumentation system , with less dispersion and amplitude of the tibial component rotation around the neutral position . Level of evidence II 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 Background and purpose — Although the use of patient-specific positioning guides ( PSPGs ) in total knee replacement ( TKR ) in theory is promising , the technique has not yet proven its superior- ity compared with the conventional method . We compared radio- logical alignment and clinical outcome between TKR performed with the use of PSPGs and the conventional operation method . Patients and methods — 3 hospitals participated in a prospec- tive trial . 109 patients were r and omized to either the conventional method or to the use of PSPGs .  Postoperatively a full-length st and ing anteroposterior radiograph and a postoperative CT scan were taken . On the CT scan the alignments were measured for both the femoral and tibial components in the frontal , sagit- tal , and axial plane . The Knee injury and Osteoarthritis Outcome Score ( KOOS ) , the Eurocol-5D-3L ( Eq5D ) descriptive system and visual analogue scale ( VAS ) , a pain score ( NRS ) , and range of motion ( ROM ) were recorded preoperatively , and at 3 months , 1 , and 2 years . The operation time and length of hospital stay were recorded . Results — 90 patients were available for postoperative CT mea- surements . A statistically significant difference was found between the conventional TKR instrumentation and the use of PSPGs for the frontal femoral ( mean ( SD ) 0.6 ° ( 1.7 ) vs. –0.3 ° ( 2.2 ) , CI 0.08 to 1.69 ) and tibial ( –0.3 ° ( 1.5 ) vs. 0.9 ° ( 2.1 ) , CI –1.98 to –0.44 ) compo- nent angles and for the tibial alignment in the sagittal plane ( –3.8 ° ( 3.0 ) vs. –2.2 ° ( 2.5 ) , CI –2.72 ; –0.42 ) . The proportions of outliers were similar between the groups as well as the hip – knee – ankle angle , the KOOS sub scores , the Eq5D , pain ( NRS ) , ROM , opera- tion time , and length of hospital stay . Interpretation — The use of PSPGs requires a preoperative CT scan or MRI and the guides have an additional cost . As this study was not able to prove any extra benefit of the use of PSPGs we recommend the conventional operation method for TKR Background Recently , patient-specific guides ( PSGs ) have been introduced , cl aim ing a significant improvement in accuracy and reproducibility of component positioning in TKA . Despite intensive marketing by the manufacturers , this cl aim has not yet been confirmed in a controlled prospect i ve trial . Questions / purpose sWe ( 1 ) compared three-planar component alignment and overall coronal mechanical alignment between PSG and conventional instrumentation and ( 2 ) logged the need for applying changes in the suggested position of the PSG . Methods In this r and omized controlled trial , we enrolled 128 patients . In the PSG cohort , surgical navigation was used as an intraoperative control . When the suggested cut deviated more than 3 ° from target , the use of PSG was ab and oned and marked as an outlier . When cranial-caudal position or size was adapted , the PSG was marked as modified . All patients underwent long-leg st and ing radiography and CT scan .  Deviation of more than 3 ° from the target in any plane was defined as an outlier . Results The PSG and conventional cohorts showed similar numbers of outliers in overall coronal alignment ( 25 % versus 28 % ; p = 0.69 ) , femoral coronal alignment ( 7 % versus 14 % ) ( p = 0.24 ) , and femoral axial alignment ( 23 % versus 17 % ; p = 0.50 ) . There were more outliers in tibial coronal ( 15 % versus 3 % ; p = 0.03 ) and sagittal 21 % versus 3 % ; p = 0.002 ) alignment in the PSG group than in the conventional group . PSGs were ab and oned in 14 patients ( 22 % ) and modified in 18 ( 28 % ) . Conclusions PSGs do not improve accuracy in TKA and , in our experience , were somewhat impractical in that the procedure needed to be either modified or ab and oned with some frequency . Level of Evidence Level I , therapeutic study . See instructions for authors for a complete description of levels of evidence 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 Total knee arthroplasty ( TKA ) is a frequently performed procedure in orthopaedic surgery . Recently , patient-specific instrumentation was introduced to facilitate correct positioning of implants . The aim of this study was to compare the early clinical results of TKA performed with patient-specific CT-based instrumentation and conventional technique . A prospect i ve , r and omized controlled trial on 112 patients was performed between January 2011 and December 2011 . A group of 112 patients who met the inclusion and exclusion criteria were enrolled in this study and r and omly assigned to an experimental or control group . The experimental group comprised 52 patients who received the Signature CT-based implant positioning system , and the control group consisted of 60 patients with conventional instrumentation .  Clinical outcomes were evaluated with the KSS scale , WOMAC scale , and VAS scales to assess knee pain severity and patient satisfaction with the surgery . Specified in-hospital data were recorded . Patients were followed up for 12 months . At one year after surgery , there were no statistically significant differences between groups with respect to clinical outcomes and in-hospital data , including operative time , blood loss , hospital length of stay , intraoperative observations , and postoperative complications . Further high- quality investigations of various patient-specific systems and longer follow-up may be helpful in assessing their utility for TKA BACKGROUND Achieving accurate alignment in total knee arthroplasty ( TKA ) remains a concern . Patient-specific instrumentation ( PSI ) produced using preoperative 3D models was developed to offer surgeons a simplified , reliable , efficient and customised TKA procedure . METHODS In this prospect i ve study , 60 patients underwent TKA with conventional instrumentation and 71 patients were operated on using PSI .  The primary endpoint was surgical time . Secondary endpoints included operating room ( OR ) time , the number of instrument trays used and postoperative radiographic limb alignment . RESULTS Compared to conventional instrumentation , PSI significantly reduced total surgical time by 8.9 ± 3.3 min ( p=0.038 ) , OR time by 8.6 ± 4.2 min ( p=0.043 ) , and the number of instrument trays by six trays ( p<0.001 ) . Mechanical axis malalignment of the lower limb of > 3 ° was observed in 13 % of PSI patients versus 29 % with conventional instrumentation ( p=0.043 ) . PSI predicted the size of the femoral and tibial components actually used in 85.9 % and 78.9 % of cases , respectively . CONCLUSION PSI  improves alignment , surgical and OR time , reduces the number of instruments 
    Output:
    
agent
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 .
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: This study develops and vali date s a novel patient-specific navigational template for total knee arthroplasty ( TKA ) . A total of 70 patients who underwent TKA were r and omized and divided into conventional method group and navigational template group . In the navigational template group , the patient-specific navigational templates were design ed and used intraoperatively to assist 35 patients with knee arthroplasty . Information on operation time and blood loss was recorded . After surgery , the positions of the prosthesis were evaluated using CT scan and X-rays . Analysis showed significant differences in errors between the two techniques . In addition , mean operation time and mean blood loss were statistically and significantly lower in the navigational template group than in the conventional group . Overall , the navigational template method showed a high degree of accuracy and efficacy Purpose To compare the femoral and tibial components rotational alignment in total knee arthroplasty ( TKA ) performed either with conventional or with patient-specific instrumentation . Methods Forty-five patients underwent primary TKA and were prospect ively r and omized into two groups : 22 patients into the conventional instrumentation group ( group A ) and 23 patients into the Signature ™ patient-specific instrumentation group ( group B ) . All patients underwent computed tomography of the operated knee in the first week after surgery to measure  the components rotation . Results The femoral component rotation was 0.0 ° ( −0.25 , 1.0 ) in group A , and 0.0 ° ( 0.0 , 1.0 ) in group B. The tibial component rotation was −16.0 ° ( −18.5 , 11.8 ) in group A , and −16.0 ° ( −19.0 , −14.0 ) in group B. There were no significant differences between the two groups in tibial and femoral components rotation . The difference between the tibial component rotation and the neutral tibial rotation was similar in both groups [ 2.0 ° ( −0.5 , 6.3 ) in group A and 2.0 ° ( −1.0 , 4.0 ) in group B ] , but the dispersion around the median was different between the two groups . The amplitude of the difference between tibial rotation and neutral position was 27 ° ( −13 , 14 ) in group A and 9 ° ( −3 , 6 ) in group B. Conclusions There is a smaller chance of internal malrotation of the tibial component with the Signature ™ patient-specific instrumentation system , with less dispersion and amplitude of the tibial component rotation around the neutral position . Level of evidence II 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 Background and purpose — Although the use of patient-specific positioning guides ( PSPGs ) in total knee replacement ( TKR ) in theory is promising , the technique has not yet proven its superior- ity compared with the conventional method . We compared radio- logical alignment and clinical outcome between TKR performed with the use of PSPGs and the conventional operation method . Patients and methods — 3 hospitals participated in a prospec- tive trial . 109 patients were r and omized to either the conventional method or to the use of PSPGs .  Postoperatively a full-length st and ing anteroposterior radiograph and a postoperative CT scan were taken . On the CT scan the alignments were measured for both the femoral and tibial components in the frontal , sagit- tal , and axial plane . The Knee injury and Osteoarthritis Outcome Score ( KOOS ) , the Eurocol-5D-3L ( Eq5D ) descriptive system and visual analogue scale ( VAS ) , a pain score ( NRS ) , and range of motion ( ROM ) were recorded preoperatively , and at 3 months , 1 , and 2 years . The operation time and length of hospital stay were recorded . Results — 90 patients were available for postoperative CT mea- surements . A statistically significant difference was found between the conventional TKR instrumentation and the use of PSPGs for the frontal femoral ( mean ( SD ) 0.6 ° ( 1.7 ) vs. –0.3 ° ( 2.2 ) , CI 0.08 to 1.69 ) and tibial ( –0.3 ° ( 1.5 ) vs. 0.9 ° ( 2.1 ) , CI –1.98 to –0.44 ) compo- nent angles and for the tibial alignment in the sagittal plane ( –3.8 ° ( 3.0 ) vs. –2.2 ° ( 2.5 ) , CI –2.72 ; –0.42 ) . The proportions of outliers were similar between the groups as well as the hip – knee – ankle angle , the KOOS sub scores , the Eq5D , pain ( NRS ) , ROM , opera- tion time , and length of hospital stay . Interpretation — The use of PSPGs requires a preoperative CT scan or MRI and the guides have an additional cost . As this study was not able to prove any extra benefit of the use of PSPGs we recommend the conventional operation method for TKR Background Recently , patient-specific guides ( PSGs ) have been introduced , cl aim ing a significant improvement in accuracy and reproducibility of component positioning in TKA . Despite intensive marketing by the manufacturers , this cl aim has not yet been confirmed in a controlled prospect i ve trial . Questions / purpose sWe ( 1 ) compared three-planar component alignment and overall coronal mechanical alignment between PSG and conventional instrumentation and ( 2 ) logged the need for applying changes in the suggested position of the PSG . Methods In this r and omized controlled trial , we enrolled 128 patients . In the PSG cohort , surgical navigation was used as an intraoperative control . When the suggested cut deviated more than 3 ° from target , the use of PSG was ab and oned and marked as an outlier . When cranial-caudal position or size was adapted , the PSG was marked as modified . All patients underwent long-leg st and ing radiography and CT scan .  Deviation of more than 3 ° from the target in any plane was defined as an outlier . Results The PSG and conventional cohorts showed similar numbers of outliers in overall coronal alignment ( 25 % versus 28 % ; p = 0.69 ) , femoral coronal alignment ( 7 % versus 14 % ) ( p = 0.24 ) , and femoral axial alignment ( 23 % versus 17 % ; p = 0.50 ) . There were more outliers in tibial coronal ( 15 % versus 3 % ; p = 0.03 ) and sagittal 21 % versus 3 % ; p = 0.002 ) alignment in the PSG group than in the conventional group . PSGs were ab and oned in 14 patients ( 22 % ) and modified in 18 ( 28 % ) . Conclusions PSGs do not improve accuracy in TKA and , in our experience , were somewhat impractical in that the procedure needed to be either modified or ab and oned with some frequency . Level of Evidence Level I , therapeutic study . See instructions for authors for a complete description of levels of evidence 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 Total knee arthroplasty ( TKA ) is a frequently performed procedure in orthopaedic surgery . Recently , patient-specific instrumentation was introduced to facilitate correct positioning of implants . The aim of this study was to compare the early clinical results of TKA performed with patient-specific CT-based instrumentation and conventional technique . A prospect i ve , r and omized controlled trial on 112 patients was performed between January 2011 and December 2011 . A group of 112 patients who met the inclusion and exclusion criteria were enrolled in this study and r and omly assigned to an experimental or control group . The experimental group comprised 52 patients who received the Signature CT-based implant positioning system , and the control group consisted of 60 patients with conventional instrumentation .  Clinical outcomes were evaluated with the KSS scale , WOMAC scale , and VAS scales to assess knee pain severity and patient satisfaction with the surgery . Specified in-hospital data were recorded . Patients were followed up for 12 months . At one year after surgery , there were no statistically significant differences between groups with respect to clinical outcomes and in-hospital data , including operative time , blood loss , hospital length of stay , intraoperative observations , and postoperative complications . Further high- quality investigations of various patient-specific systems and longer follow-up may be helpful in assessing their utility for TKA BACKGROUND Achieving accurate alignment in total knee arthroplasty ( TKA ) remains a concern . Patient-specific instrumentation ( PSI ) produced using preoperative 3D models was developed to offer surgeons a simplified , reliable , efficient and customised TKA procedure . METHODS In this prospect i ve study , 60 patients underwent TKA with conventional instrumentation and 71 patients were operated on using PSI .  The primary endpoint was surgical time . Secondary endpoints included operating room ( OR ) time , the number of instrument trays used and postoperative radiographic limb alignment . RESULTS Compared to conventional instrumentation , PSI significantly reduced total surgical time by 8.9 ± 3.3 min ( p=0.038 ) , OR time by 8.6 ± 4.2 min ( p=0.043 ) , and the number of instrument trays by six trays ( p<0.001 ) . Mechanical axis malalignment of the lower limb of > 3 ° was observed in 13 % of PSI patients versus 29 % with conventional instrumentation ( p=0.043 ) . PSI predicted the size of the femoral and tibial components actually used in 85.9 % and 78.9 % of cases , respectively . CONCLUSION PSI  improves alignment , surgical and OR time , reduces the number of instruments 
    Output:
    