Patient specific cutting blocks are currently of no proven value. Accuracy of manual instrumentation of tibial cutting guide in total knee arthroplasty Comparison between patient-specific instruments and conventional instruments and computer navigation in total knee arthroplasty: a randomized controlled trial The accuracy of component alignment in custom cutting blocks compared with conventional total knee arthroplasty instrumentation: prospective control trial. Component alignment and clinical outcome following total knee arthroplasty: a randomised controlled trial comparing an intramedullary alignment system with patient-specific instrumentation. A comparison of patient-specific and conventional instrumentation for total knee arthroplasty: a multicentre randomised controlled trial. Comparison of two minimally invasive implantation instrument-sets for total knee arthroplasty Patient-specific computed tomography based instrumentation in total knee arthroplasty: a prospective randomized controlled study In-vivo alignment comparing patient specific instrumentation with both conventional and computer assisted surgery (CAS) instrumentation in total knee arthroplasty. Contribution of patient-specific cutting guides to lower limb alignment for total knee arthroplasty. Patient-specific instrumentation improved mechanical alignment, while early clinical outcome was comparable to conventional instrumentation in TKA The radiological outcomes of patient-specific instrumentation versus conventional total knee arthroplasty Reliability of templating with patient-specific instrumentation in total knee arthroplasty. Patient-specific Total Knee Arthroplasty Required Frequent Surgeon-directed Changes Comparison of Early Postoperative Rehabilitation Outcome following Total Knee Arthroplasty Using Different Surgical Approaches and Instrumentation A systematic review of psychological interventions in total hip and knee arthroplasty Component alignment during total knee arthroplasty with use of standard or custom instrumentation: a randomized clinical trial using computed tomography for postoperative alignment measurement. Patient-specific Guides Do Not Improve Accuracy in Total Knee Arthroplasty: A Prospective Randomized Controlled Trial The value of patient-matched instrumentation in total knee arthroplasty. Comparison of radiographic alignment of imageless computer-assisted surgery vs conventional instrumentation in primary total knee arthroplasty. Patient-matched instruments versus standard instrumentation in total knee arthroplasty: a prospective randomized study Rotation in total knee arthroplasty: no difference between patient-specific and conventional instrumentation Short-Term Outcome after Computer-Assisted versus Conventional Total Knee Arthroplasty: A Randomised Controlled Trial
Patient specific cutting guides generated by preoperative Magnetic Resonance Imaging ( MRI ) of the patient 's extremity have been proposed as a method of improving the consistency of Total Knee Arthroplasty ( TKA ) alignment and adding efficiency to the operative procedure . The cost of this option was evaluated by quantifying the savings from decreased operative time and instrument processing costs compared to the additional cost of the MRI and the guide .  Coronal plane alignment was measured in an unselected consecutive series of 200 TKAs , 100 with st and ard instrumentation and 100 with custom cutting guides .  While the cutting guides had significantly lower total operative time and instrument processing time , the estimated $ 322 savings was overwhelmed by the $ 1,500 additional cost of the MRI and the cutting guide . All measures of coronal plane alignment were equivalent between the two groups . The data does not currently support the proposition that patient specific guides add value to TKA Purpose The aim of this study was to evaluate the accuracy of conventional instrumentation for tibial resection in total knee arthroplasty ( TKA ) as assessed by a computer-based navigation system during each phase of the surgical procedure . The hypothesis is that conventional instrumentation fails to achieve optimal accuracy in final implant positioning , thus leading to surgical errors . Methods Forty primary TKAs were performed .  The resection guide was placed using an extramedullary guide . Accurate guide positioning was assessed by the navigation system prior to the osteotomy . The alignment measurement was repeated after resection and after component implantation in order to quantify the deviation caused by the manual positioning of the prosthetic components . A deviation ≥2 ° was considered unsatisfactory . Results In the frontal plane , unsatisfactory results observed were as follows : 15 % with reference to manual positioning of the resection guide and 10 % with reference to definition of the resection plane with a tendency towards varus malalignment . In the sagittal plane , unsatisfactory results were as follows : 45 % with reference to manual positioning of the resection guide and 40 % with reference to definition of the resection plane with a trend of decreased tibial slope angle . The deviation between bone resection and subsequent implant placement was ≥2 ° in none of the cases . Conclusions The study confirms the hypothesis that conventional instrumentation fails to achieve optimal accuracy in the positioning of the tibial component . During each phase of the surgical procedure , a tendency towards varus malalignment and a decreased tibial slope angle were observed . Levels of evidence II Abstract Purpose The current study investigated the accuracy in achieving proper lower limb alignment and individual component positions after total knee arthroplasty ( TKA ) with 3 different instrumentation techniques . It was hypothesized that patient-specific instruments ( PSI ) would achieve more accurate lower limb alignment and component positions compared to conventional instruments ( CON ) . Methods Ninety knees in 81 patients were r and omized in 1:1:1 ratio into  CON , computer navigation ( NAV )  and PSI  groups to receive TKA . The surgical routines were st and ardized . The lower limb mechanical axis and individual component positions were assessed on st and ard radiographs . Tourniquet time , operation time and patients ’ functional scores were documented . Results Conventional instruments and PSI were more likely to result in an excessively flexed femoral component ( p = 0.001 ) compared to NAV . Number of outliers in postoperative lower limb alignment , and other components positions in the coronal and sagittal plane showed no statistically significant difference . The mean tourniquet time and operation time was significantly shorter in CON and PSI groups than NAV group ( p < 0.001 ) . Four early complications occurred in the PSI group ( p = 0.015 ) . At 3-month follow-up , there was no difference in terms of the knee range of motion and patients ’ function among the 3 groups . Conclusion No significant radiological and clinical benefit could be demonstrated in using PSI over CON or NAV in TKA . Routine use of PSI is not recommended because of the extra cost and waiting time . Level of evidence BACKGROUND The purpose of this study was to assess whether custom cutting blocks improve accuracy of component alignment compared to conventional TKA instrumentation . METHODS Eighty primary TKA patients were enrolled in an open-label r and omized prospect i ve clinical trial and were divided into two groups , 40 custom cutting blocks and 40 conventional TKA instrumentations . The primary outcome was prosthetic alignment with respect to mechanical axis and epicondylar axis . Secondary outcomes included operative time , 24-hour postoperative blood loss and hemoglobin at discharged . RESULTS There were no statistical significant differences in the postoperative mechanical axis between the custom cutting blocks group and conventional TKA group , ( 95 % vs. 87.5 % within 3 ° of neutral mechanical alignment , p=0.192 ) . The average rotational alignment was statistically significantly different in the custom cutting blocks group ( 1.0 ° ±0.6 ° vs. 1.6 ° ±1.8 ° external rotation from epicondylar axis , p<0.001 ) . There were statistical significant differences in operation time  between custom cutting blocks group and conventional group , skin to skin [ 57.5±2.3 min vs. 62.1±1.5 , p<0.001 ] . We found an improvement in group 1 compared with group 2 regarding the proportion of patients with postoperative blood loss within 24 h. CONCLUSIONS Custom cutting blocks technique was a surgical procedure which provided better accuracy in rotational alignment but no statistical differences in mechanical axis , less operative time and reduced blood loss  than the conventional TKA instrumentation in the majority of patients AIMS We conducted a r and omised controlled trial to assess the accuracy of positioning and alignment of the components in total knee arthroplasty ( TKA ) , comparing those undertaken using st and ard intramedullary cutting jigs and those with patient-specific instruments ( PSI ) . PATIENTS AND METHODS There were 64 TKAs in the st and ard group and 69 in the PSI group . The post-operative hip-knee-ankle ( HKA ) angle and positioning was investigated using CT scans . Deviation of > 3 ° from the planned position was regarded as an outlier . The operating time , Oxford Knee Scores ( OKS ) and Short Form-12 ( SF-12 ) scores were recorded . RESULTS There were 14 HKA-angle outliers ( 22 % ) in the st and ard group and nine ( 13 % ) in the PSI group ( p = 0.251 ) . The mean HKA-angle was 0.5 ° varus in the st and ard group and 0.2 ° varus in the PSI group ( p = 0.492 ) . The accuracy of alignment in the coronal and axial planes and the proportion of outliers was not different in the two groups . The femoral component was more flexed ( p = 0.035 ) and there were significantly more tibial slope outliers ( 29 % versus 13 % ) in the PSI group ( p = 0.032 ) . Operating time and the median three-month OKS were similar ( p = 0.218 and p = 0.472 , respectively ) . Physical and mental SF-12 scores were not significantly different at three months ( p = 0.418 and p = 0.267 , respectively ) or at one year post-operatively ( p = 0.114 and p = 0.569 ) . The median one-year Oxford knee score was two points higher in the PSI group ( p = 0.049 ) . CONCLUSION Compared with st and ard intramedullary jigs , the use of PSI did not significantly reduce the number of outliers or the mean operating time , nor did it clinical ly improve the accuracy of alignment or the median Oxford Knee Scores . Our data do not support the routine use of PSI when undertaking TKA . Cite this article : Bone Joint J 2016;98-B:1043 - 9 In this study we r and omised 140 patients who were due to undergo primary total knee arthroplasty ( TKA ) to have the procedure performed using either patient-specific cutting guides ( PSCG ) or conventional instrumentation ( CI ) . The primary outcome measure was the mechanical axis , as measured at three months on a st and ing long-leg radiograph by the hip-knee-ankle ( HKA ) angle . This was undertaken by an independent observer who was blinded to the instrumentation . Secondary outcome measures were component positioning , operating time , Knee Society and Oxford knee scores , blood loss and length of hospital stay . A total of 126 patients ( 67 in the CI group and 59 in the PSCG group ) had complete clinical and radiological data . There were 88 females and 52 males with a mean age of 69.3 years ( 47 to 84 ) and a mean BMI of 28.6 kg/m(2 ) ( 20.2 to 40.8 ) .  The mean HKA angle was 178.9 ° ( 172.5 to 183.4 ) in the CI group and 178.2 ° ( 172.4 to 183.4 ) in the PSCG group ( p = 0.34 ) . Outliers were identified in 22 of 67 knees ( 32.8 % ) in the CI group and 19 of 59 knees ( 32.2 % ) in the PSCG group ( p = 0.99 ) . There was no significant difference in the clinical results ( p = 0.95 and 0.59 , respectively ) . Operating time , blood loss and length of hospital stay were not significantly reduced ( p = 0.09 , 0.58 and 0.50 , respectively ) when using PSCG . The use of PSCG in primary TKA did not reduce the proportion of outliers as measured by post-operative coronal alignment Several choices of instrument systems are available for minimally invasive surgical approaches . There are reports that one alternative , the quadriceps sparing , side-cutting instrumentation , results in diminished implantation accuracy . A total of 108 patients were r and omized to undergo TKA either using side-cutting implant instrumentation ( Group A ) or anterior – posterior mini-incision instrumentation ( Group B ) . All TKAs were operated on with a minimal invasive , mini-midvastus surgical approach . 50 % of the TKAs were performed with computer-assistance in each cohort . The radiographic parameters , clinical outcomes and knee scores were evaluated preoperatively and 3 months postoperative . In Group B , we found significantly higher accuracy for the mechanical axis of the limb ( range ±3 ° : Group A 54 % versus Group B 89 % , p = < 0.001 ) , medial proximal tibial angle ( range ±3 ° : Group A 85 % versus Group B 98 % , p = < 0.027 ) and tibial slope ( range ±3 ° : Group A 59 % versus Group B 85 % , p = < 0.007 ) . The application of the navigation system could only significantly reduce outliers ( accuracy > 3 ° ) in Group B. Clinical outcomes and knee scores were similar in both groups and were not influenced by computer-assistance . Using the anterior – posterior , mini-incision instruments for minimally invasive TKA will lead to higher implantation accuracy when compared to the quadriceps sparing side-cutting instrumentation . The navigation technique could not compensate for shortcomings of the side-cutting instrumentation . The clinical relevance of this study is that the quadriceps sparing side-cutting instrumentation should not be used for TKA because of unacceptable reduced implantation accuracy Purpose The aim of this study was to compare radiological results of total knee arthroplasties ( TKAs ) performed with patient-specific computed tomography (CT)-based instrumentation and conventional technique . The main study hypothesis was that CT-based patient-specific instrumentation ( PSI ) increases the accuracy of TKA . Methods A prospect i ve , r and omized controlled trial was carried out between January 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 operated on with the aid of the Signature ™ CT-based implant positioning system .  The control group consisted of 60 patients operated on using conventional instrumentation .  The radiographic evaluation of implant positioning and overall coronal alignment was performed 12 months after the surgery by using st and ing anteroposterior radiographs of the entire lower limb and st and ard lateral radiographs . Results Of the 112 patients initially enrolled for the study , 95 were included in the subsequent analyses . There were no statistically significant differences between groups in respect to coronal and sagittal component positioning and overall coronal alignment , except for frontal tibial component positioning . For this parameter , better results were obtained in the control group , with borderline statistical significance . Conclusions Our study did not reveal superiority of the CT-based PSI system over conventional instrumentation . Further high- quality investigations of patient-specific systems are absolutely indispensable to assess their utility for TKA . In our opinion , the surgeon applying PSI technology is required to have advanced knowledge and considerable experience with the conventional method Patient specific instrumentation ( PSI ) was developed to increase total knee arthroplasty ( TKA ) accuracy and efficiency . The study purpose was to compare immediate post-operative mechanical alignment , achieved using PSI , with conventional and computer assisted surgery ( CAS ) instruments in high volume TKA practice s. This prospect i ve , multicenter , non-r and omized study accrued 66 TKA patients using PSI .  A computed tomography ( CT ) based algorithm was used to develop the surgical plan . Sixty-two percent were females , 99 % were diagnosed with osteoarthritis , average age at surgery was 66 years , and 33 was the average body mass index . A historical control group was utilized that underwent TKA using conventional instruments ( n=86 ) or CAS ( n=81 ) , by the same set of surgeons . Postoperative mechanical alignment was comparable across the groups . Operative time mean and variance were significant UNLABELLED Patient-specific cutting guides ( PSCG ) are an extension of preoperative planning for total knee arthroplasty ( TKA ) . We wanted to evaluate their contribution to postoperative lower limb alignment . This study involved primary TKA cases being performed with PSCG between 10/05/2010 and 05/03/2013 and then followed prospect ively . The analysis involved the PSCG usage and postoperative measurement of the patient 's HKA , medial distal femoral joint angle ( MDFA ) and medial proximal tibia joint angle ( MPTA ) .  Of the 104 eligible cases , 68 were included ; 11 of these cases were not performed completely with the PSCG as initially planned . Thus we compared these 11 cases with the 57 where PSCG were used . The preoperative HKA in the included cases was 175.8 ° ± 7.8 ; the postoperative angles on average were 179.2 ° ± 2.9 for the HKA , 89.9 ° ± 1.6 for the MDFA and 89.0 ° ± 2.3 for the MPTA . The average postoperative deviation from the target values was 2.22 ° ± 2.14 for the HKA angle , 1.07 ° ± 1.15 for the MDFA and 1.66 ° ± 1.90 for the MPTA . There were no significant differences between the two groups in any of the measurements . The lower limb alignment goal was achieved in 50 cases ( 73 % ) , with 41 of these achieved with PSCG ( 82 % ) . Of the 18 cases where the target was not achieved , PSCG were used 16 times ( 88 % ) . In this study cohort , lower limb alignment was not significantly closer to an HKA of 180 ° or achieved more often with the use of PSCG versus st and ard instrumentation . Since the results of the two groups can be superimposed , we found no evidence that use of PSCG  improves postoperative lower limb alignment . LEVEL OF EVIDENCE IV . STUDY TYPE Cohort Abstract Purpose The aim of this prospect i ve study was to compare early clinical outcome , radiological limb alignment , and three-dimensional (3D)-component positioning between conventional and computed tomography (CT)-based patient-specific instrumentation ( PSI ) in primary mobile-bearing total knee arthroplasty ( TKA ) . Methods Two hundred ninety consecutive patients ( 300 knees ) with severe , debilitating osteoarthritis scheduled for TKA were included in this study using either conventional instrumentation ( CVI , n = 150 ) or PSI ( n = 150 ) . Patients were clinical ly assessed before and 2 years after surgery according to the Knee-Society-Score ( KSS ) and the visual-analog-scale for pain ( VAS ) . Additionally , the Western Ontario McMaster Universities Osteoarthritis Index ( WOMAC ) and the Oxford-Knee-Score ( OKS ) were collected at follow-up . To evaluate accuracy of CVI and PSI , hip-knee-ankle angle ( HKA ) and 3D-component positioning were assessed on postoperative radiographs and CT . Results Data of 222 knees ( CVI : n = 108 , PSI : n = 114 ) were available for analysis after a mean follow-up of 28.6 ± 5.2 months . At the early follow-up , clinical outcome ( KSS , VAS , WOMAC , OKS ) was comparable between the two groups . Mean HKA-deviation from the targeted neutral mechanical axis ( CVI : 2.2 ° ± 1.7 ° ; PSI : 1.5 ° ± 1.4 ° ; p < 0.001 ) , rates of outliers ( CVI : 22.2 % ; PSI : 9.6 % ; p = 0.016 ) , and 3D-component positioning outliers were significantly lower in the PSI group . Non-outliers ( HKA : 180 ° ± 3 ° ) showed better clinical results than outliers at the 2-year follow-up . Conclusions CT-based PSI compared with CVI improves accuracy of mechanical alignment restoration and 3D-component positioning in primary TKA . While clinical outcome was comparable between the two instrumentation groups at early follow-up , significantly inferior outcome was detected in the subgroup of HKA-outliers . Level of evidence Prospect i ve comparative study , Level II Abstract Purpose The aim of this study was to investigate the post-operative radiological outcomes of patient-specific instrumentation ( PSI ) surgery versus conventional total knee arthroplasty ( TKA ) . Methods Sixty patients scheduled for a primary TKA were prospect ively divided into PSI or conventional technique . Coronal and sagittal radiographic long limb films were taken post-operatively . The accepted values for normal alignment were 180 ° ± 3 ° for hip-knee-ankle angle ; 90 ° ± 3 ° for coronal femoral component angle or coronal tibia component angle ; 0 ° to 3 ° flexion for sagittal femoral component angle and 0 ° to 7 ° posterior slope for sagittal tibia component angle . Results For hip-knee-ankle angle , there were 21 % more outliers in the PSI group compared to the conventional group ( p = 0.045 ) . Most of these outliers had valgus deformity in the PSI group and varus deformity in the conventional group ( p = 0.045 ) . For implant placement , there was no difference in the proportion of outliers between the two groups . There was also no difference in the duration of surgery . Conclusions This study showed that PSI surgery is associated with a larger proportion of outliers for lower limb alignment . PSI surgery as an alternative to conventional TKA is not advisable . Level of evidence II Magnetic resonance imaging ( MRI ) or computed tomography-based patient-specific instrumentation ( PSI ) may allow for reliable alignment and fewer outliers when compared with conventionally instrumented total knee arthroplasty ( TKA ) . However , some authors have suggested that frequent intraoperative surgeon-directed changes may still be required . This study evaluated the accuracy of  PSI  to predict component sizing and alignment during TKA . A total of 84 patients ( 89 knees ) who underwent a TKA using a PSI system were evaluated . An MRI-based preoperative plan of every knee was provided and approved by the surgeons . This demonstrated the proposed prosthetic component alignment , as well as the femoral , tibial , and bearing insert component size and position . Intraoperative changes to these components were prospect ively recorded and compared with the computerized preoperative plan . Major changes were defined as any changes in femoral or tibial resection , size , and position of the components . Minor changes were defined as any change in the size of the polyethylene bearing insert . The preoperative plan was able to correctly predict the size of the implanted tibial and femoral component in 93 and 95.5 % of the cases , respectively . Thirteen major intraoperative changes were made . In one knee , the proposed femoral resection was not acceptable ( because of the presence of significant amount of osteophytes ) and was ab and oned in favor of a manual extramedullary guide . In another patient , the proposed femoral and tibial components were upsized . In two other patients , the femoral components were downsized , in four patients , the tibial components were downsized , and in another patient , it was upsized . There were also 16 minor changes , which included 2-mm upsizing of the polyethylene liner in 13 knees and 4-mm upsizing in 3 knees . Surgical experience is necessary to recognize improper component size , incorrect surgical resection , or nonideal alignment when performing TKA using PSI . The authors believe that the design and manufacture of PSI combined with a comprehensive templating result ed in excellent intraoperative concordance of the preoperative plan at the default setting s with minimal changes Background Patient-specific instrumentation potentially improves surgical precision and decreases operative time in total knee arthroplasty ( TKA ) but there is little supporting data to confirm this presumption . Questions / purpose sWe asked whether patient-specific instrumentation would require infrequent intraoperative changes to replicate a single surgeon ’s preferences during TKA and whether patient-specific instrumentation guides would fit securely . Methods We prospect ively evaluated the plan and surgery in 60 patients treated with 66 TKAs performed with patient-specific instrumentation and recorded any changes . A subset of six postoperative radiographic changes to the femoral and tibial components ( implant size , coronal and sagittal alignment ) was analyzed to determine if surgeon intervention was beneficial . Each guide was evaluated to determine fit . We compared patient demographics and implant sizing in the patient-specific instrumentation group with a control group in which traditional instrumentation was used . Results We recorded 161 intraoperative changes in 66 knee arthroplasties ( 2.4 changes/knee ) performed with patient-specific instrumentation . The predetermined implant size was changed intraoperatively in 77 % of femurs and 53 % of tibias . We identified a subset of 95 intraoperative changes that could be radiographically evaluated to determine if our changes were an improvement or detriment to reaching goal alignment . Eighty-two of the 95 changes ( 86 % ) made by the surgeon were an improvement to the recommended alignment or size of patient-specific instrumentation . The guide did not fit securely on eight femurs ( 12 % ) and three tibias ( 5 % ) . Tourniquet time and blood loss were not improved with patient-specific instrumentation . Conclusions We caution surgeons against blind acceptance of patient-specific instrumentation technology without supportive data .Level of Evidence Level III , therapeutic study . See Guidelines for Authors for a complete description of levels of evidence Purpose . To assess early postoperative rehabilitation outcome following  computer-assisted total knee arthroplasty ( TKA )  or st and ard instrumentation TKA using a medial parapatellar or subvastus approach . Methods . A prospect i ve controlled trial of 70 consecutive patients undergoing TKA with a low contact stress rotating platform prosthesis was conducted . Patients were r and omised to receive surgery with either computer navigation or st and ard instrumentation .  A medial parapatellar or subvastus approach was used according to the surgeons ' preference . Outcome measures included preoperative knee function , intra-operative factors , and postoperative rehabilitation . Results . Duration of surgery was significantly longer when using computer navigation ; however , operating time decreased with greater experience . A higher incidence and duration of early postoperative quadriceps dysfunction was associated with computer-assisted TKA through the medial parapatellar approach than through the subvastus approach or TKA performed with st and ard instrumentation . No patient who received surgery through the subvastus approach had a lag of more than 20 degrees , at 48 hours postoperatively , regardless of the instrumentation used . Conclusion . Computer-assisted TKA through a medial parapatellar approach was associated with delayed recovery of the quadriceps during early postoperative rehabilitation . This was due to the additional quadriceps dissection required to place the femoral tracking array . The subvastus approach is therefore recommended for computer-assisted TKA Background The current practice in elective orthopaedics does not routinely include psychological interventions despite evidence that psychological factors such as personality , anxiety , depression and negative thinking styles can influence outcomes and recovery from surgery . The objective of this paper was to review the effectiveness of psychological interventions used in conjunction with total hip ( THA ) and knee arthroplasty ( TKA ) , in improving patient reported joint outcomes . Methods An extensive literature search was conducted according to Preferred Reporting Items for Systematic review s and Meta-Analyses guidelines . Search terms included psychology , interventions , and orthopaedics . Articles were included if they were r and omised controlled trials ( RCTs ) of psychological interventions involving active patient participation measured with patient reported joint outcomes in patients undergoing hip or knee arthroplasty . Results A total of 19,489 titles were screened . Seven studies met the inclusion criteria and were included . Five of seven studies did not show improvements in patient reported outcomes after surgery . Specifically , psycho-education alone was not effective at improving patient reported joint outcomes in two out of two studies . Conclusion The current literature does not support routine psychological interventions for TKA and THA . However , it should be noted that the literature for psychological interventions in conjunction with TKA and THA is still in its infancy . This gap in the literature is surprising , considering the importance of the role of psychological factors in recovery . Further RCTs with long term follow ups , multidisciplinary involvement , and more comprehensive and focused interventions that go beyond educating patients are needed . Future studies should account for the dem and effect , include measures of psychological variables to determine whether psychological interventions are more beneficial for some patients compared to others , and compare the different modes of delivery and timing of interventions to determine the optimal nature and duration of psychological interventions for TKA and THA 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 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 The purpose of the current prospect i ve , r and omized study was to compare the value of a new mechanically aligned patient-matched instrument system for total knee arthroplasty ( TKA ) ( Visionaire ; Smith & Nephew , Inc , Memphis , Tenn ) ( VIS ) to that of st and ard TKA surgical instrumentation ( STD ) . Twenty-nine primary TKA patients were enrolled and completed surgery ( 15 VIS and 14 STD ) . Postoperatively , mechanical alignment was significantly closer to neutral zero in the VIS group ( 1.7 ° vs 2.8 ° ; P = .03 ) . Furthermore , the VIS group demonstrated significant reductions in duration of hospital stay , operative time , incision length , and number of used instrument trays ( P < .05 ) . Although additional research is underway to confirm these preliminary results , this evidence suggests that patient-matched instrumentation may support repeatable improvements in surgical accuracy and hospital efficiency A total of 208 patients were enrolled in a multicenter , prospect i ve r and omized , institutional review board-approved study that compared preoperative surgical plan to postoperative 2-dimensional radiographic alignment measured by a blinded review er for  primary total knee arthroplasty ( TKA ) implanted using computer-assisted surgery ( CAS ) compared with conventional TKA instrumentation . The results demonstrated a statistically significant improvement in the coronal tibial component alignment ( P < .03 ) and failed to demonstrate a statistically significant improvement in the mechanical axis , femoral coronal/sagittal , and tibial sagittal alignment . Knee Society Score knee and function scores and 6-minute walk test were equivalent between the 2 treatment groups at all postoperative intervals . There was a statistically significant increase in the skin-skin time ( P < .0001 ) and the time until first bone cut ( P < .0001 ) for the CAS knees compared with those implanted with conventional instrumentation . The use of CAS in this r and omized clinical trial conducted at high-volume centers did not offer a clinical ly meaningful improvement in postoperative alignment , clinical , functional , or safety outcomes compared with conventional TKA Summary Background Optimal positioning of implants and restoration of neutral mechanical axis are two primary surgical goals in total knee arthroplasty ( TKA ) . Despite modern instruments and improved surgical techniques , malalignment remains an important cause of early failure after TKA . The aim of this prospect i ve r and omized study was to compare the value of a new patient-matched instrument system ( PMI ) ( SignatureTM ; Biomet , Inc , Warsaw , Indiana ) to that of st and ard TKA surgical instrumentation ( STD ) in terms of coronal mechanical alignment , time of operation and blood loss . Patients and methods A total of 38 patients waiting for primary TKA were enrolled and r and omized into two groups ( 19 PMI and 19 STD ) . Magnetic resonance imaging was performed in all patients in the PMI group , and specific instruments for the femur and tibia were design ed preoperatively . All patients were operated on using the st and ard medial parapatellar approach with no use of tourniquet . Mechanical axis , time for the operation , and blood loss were evaluated . Results Patients in both groups had comparable age , body mass index , preoperative mechanical axis , Knee Society Score , and level of hemoglobin . Postoperative results showed that the PMI group fell significantly closer to neutral mechanical axis ( STD : 2.7 ± 1.7 , PMI : 1.7 ± 0.9 ; P = 0.013 ) with no outliers and a reduced time for the operation . There was no difference in the evaluation blood loss . Conclusions The use of PMI can contribute in achieving better mechanical axis with reduction in outliers and decreased operation time . Due to small differences between PMI and st and ard instruments , additional research are needed to confirm these preliminary results , and to discover potential benefits and functional improvements in the long-term outcome 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 Purpose . To compare the short-term functional outcome after computer-assisted total knee arthroplasty ( TKA )  versus conventional TKA . Methods . 23 men and 67 women aged 48 to 80 years were r and omised to undergo ( 1 ) conventional TKA using an intramedullary guide , ( 2 ) conventional TKA using an extramedullary guide , or ( 3 ) computer-assisted TKA . Two senior surgeons performed all the TKAs using the same TKA system and the st and ard anteromedial arthrotomy with eversion of the patella . Patients were assessed by physiotherapists before and 6 months and 2 years after TKA using the Short Form-36 Health Survey , Oxford Knee Score , and Knee Society Score . Results . Of the 90 patients , 67 and 70 were assessed at 6 months and 2 years after TKA , respectively . No patient developed deep infection or required revision surgery . Functional outcomes of the 3 groups did not differ significantly at the corresponding follow-ups . Conclusion . Significant improvement in the functional outcome was not shown in patients treated with  computer-assisted TKA  , compared with conventional TKA . Thus , computer-assisted TKA has limited additional short-term benefits . Further studies with longer follow-up are required to examine the benefits of computer-assisted TKA
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 .