title: Rotation in total knee arthroplasty: no difference between patient-specific and conventional instrumentation Patient-specific Guides Do Not Improve Accuracy in Total Knee Arthroplasty: A Prospective Randomized Controlled Trial 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 Total Knee Arthroplasty Required Frequent Surgeon-directed Changes The Cochrane Collaboration’s tool for assessing risk of bias in randomised trials Patient-specific instrumentation does not shorten surgical time: a prospective, randomized trial. In-vivo alignment comparing patient specific instrumentation with both conventional and computer assisted surgery (CAS) instrumentation in total knee arthroplasty. The radiological outcomes of patient-specific instrumentation versus conventional total knee arthroplasty Contribution of patient-specific cutting guides to lower limb alignment for total knee arthroplasty. Patient-specific computed tomography based instrumentation in total knee arthroplasty: a prospective randomized controlled study The value of patient-matched instrumentation in total knee arthroplasty. Patient-specific total knee arthroplasty: the importance of planning by the surgeon Bad reporting does not mean bad methods for randomised trials: observational study of randomised controlled trials performed by the Radiation Therapy Oncology Group Comparison of robotic-assisted and manual implantation of a primary total hip replacement. A prospective study. A prospective randomised controlled study of patient-specific cutting guides compared with conventional instrumentation in total knee replacement. Is TKA Using Patient-specific Instruments Comparable to Conventional TKA? A Randomized Controlled Study of One System
abstract: 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 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 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 Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more The primary purpose of this prospect i ve , r and omized study was to determine if patient-specific instrumentation ( PSI ) for total knee arthroplasty ( TKA ) shortened surgical time . Secondarily the number of instrument trays and alignment were also compared to cases performed with traditional instrumentation ( TI ) .  Fifty-two cases ( 26 per group ) were r and omized and videotaped to measure the length of surgery , as well as each individual surgical step . Component alignment and mechanical axis was measured radiographically for each patient . Total surgical time was over 4 minutes shorter for patients in the TI group ( 57.4 minutes vs. 61.8 minutes ; P<0.01 ) . More instrument trays were used in the TI group ( 7.3 vs. 2.5 ; P<0.001 ) . There was no significant difference in mechanical alignment between groups on postoperative long alignment radiographs ( P=0.77 ) . In conclusion , PSI did not shorten surgical time or improve alignment compared with TI in this prospect i ve , r and omized trial , but did reduce the required number of trays 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 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 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 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 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 Abstract Purpose The purpose of the study was to evaluate the accuracy of the planning of the patient-specific pin guides in total knee arthroplasty ( TKA ) . This planning was performed primarily by a technician of the company and offered to the surgeon . All parameters of the implantation can either be modified or accepted by the surgeon . The hypothesis was that the plan needs preoperative intervention by the surgeon . Methods A prospect i ve study in 50 patients was carried out . All patients received the same posterior-stabilised implant with patient-specific instrumentation . All surgical parameters ( coronal , sagittal , rotational alignment , femoral and tibial resection levels and implant sizes ) were checked by the orthopaedic surgeon and changed if necessary . Results Preoperatively , the femoral size was changed in 8 patients ( 16 % ) , the femoral flexion in 23 patients ( 46 % ) , the femoral shift in 34 patients ( 68 % ) , the tibial size in 24 patients ( 48 % ) and the tibial rotation in all patients . The epicondylar axis was accepted in 47 patients ( 94 % ) in the technician plan . Mean planning time was 8 ± 4 min . Intraoperatively , the femoral anterior – posterior size was in 50 patients ( 100 % ) the same as in the surgeon and in 42 patients ( 84 % ) the same as in the technician plan ( p = 0.003 ) . The tibial component implanted was in 42 patients ( 84 % ) the same as in the surgeon and in 19 patients ( 38 % ) the same as in the technician plan ( p < 0.0001 ) . A femoral distal recut was necessary in 31 patients ( 62 % ) and a change of the tibial proximal cut in 17 patients ( 34 % ) during surgery . Intraoperatively , no changes of the femoral and tibial alignment , the femoral anterior – posterior size , the femoral flexion , the femoral shift , the femoral and tibial rotation were necessary . Postoperatively , the coronal mechanical overall axis was within ±3 ° in 47 patients ( 94 % ) with a maximum deviation of 5.6 ° . Conclusions Significant changes of the technician plan were necessary to get an accurate preoperative plan . Intraoperative changes were significant less compared to the surgeon than to the technician plan . No major changes ( alignment , femoral anterior – posterior size and rotation ) of the surgeon plan were necessary . Surgeons using patient-specific pin guides in TKA may verify the default plan provided by the technician . A blind reply on the technician plan may be not recommended . Level of evidence Therapeutic study , Level III Abstract Objective To determine whether poor reporting of methods in r and omised controlled trials reflects on poor methods . Design Observational study . Setting Reports of r and omised controlled trials conducted by the Radiation Therapy Oncology Group since its establishment in 1968 . Participants The Radiation Therapy Oncology Group . Outcome measures Content of reports compared with the design features described in the protocol s for all r and omised controlled trials . Results The method ological quality of 56 r and omised controlled trials was better than reported . Adequate allocation concealment was achieved in all trials but reported in only 42 % of papers . An intention to treat analysis was done in 83 % of trials but reported in only 69 % of papers . The sample size calculation was performed in 76 % of the studies , but reported in only 16 % of papers . End points were clearly defined and α and βerrors were prespecified in 76 % and 74 % of the trials , respectively , but only reported in 10 % of the papers . The one exception was the description of drop outs , where the frequency of reporting was similar to that contained in the original statistical files of the Radiation Therapy Oncology Group . Conclusions The reporting of method ological aspects of r and omised controlled trials does not necessarily reflect the conduct of the trial . Review ing research protocol s and contacting trialists for more information may improve quality assessment BACKGROUND Robotic-assisted total hip replacement  has become a common method of implantation , especially in Europe . It frequently has been postulated that robotic reaming would result in an improved clinical outcome due to the better fit of the prosthesis , but that has never been demonstrated in a prospect i ve study , to our knowledge . The purpose of this study was to compare robotic-assisted implantation of a total hip replacement with conventional manual implantation . METHODS One hundred and fifty-four patients scheduled for total hip replacement were r and omly assigned to undergo either conventional manual implantation of an S-ROM prosthesis ( eighty patients ) or robotic-assisted implantation of such a prosthesis ( seventy-four patients ) . The five-axis ROBODOC was used for the robotic-assisted procedures . Preoperatively as well as at three , six , twelve , and twenty-four months after surgery , the scores according to the Harris and Merle d'Aubigné systems and the Mayo clinical score were determined . Radiographs made at these intervals were analyzed for evidence of loosening , prosthetic alignment , and heterotopic ossification . RESULTS Thirteen ( 18 % ) of the seventy-four attempted robotic implantations had to be converted to manual implantations as a result of failure of the system . The duration of the robotic procedures  was longer than that of the manual procedures ( mean and st and ard deviation,107.1 + /- 29.1 compared with 82.4 + /- 23.4 minutes , p < 0.001 ) . Limb-length e quality ( mean discrepancy , 0.18 + /- 0.30 compared with 0.96 + /- 0.93 cm , p < 0.001 ) and varus-valgus orientation of the stem ( mean angle between the femur and the shaft of the prosthesis , 0.34 degrees + /- 0.67 degrees compared with 0.84 degrees + /- 1.23 degrees , p < 0.001 ) were better after the robotic procedures . At six months , slightly more heterotopic ossification was seen in the group treated with robotic implantation . The group treated with robotic implantation had a better Mayo clinical score at six and twelve months and a better Harris score at twelve months ; however , by twenty-four months , no difference was found between the groups with regard to any of the three scores . Dislocation was more frequent in the group treated with robotic implantation : it occurred in eleven of the sixty-one patients in that group compared with three of eighty in the other group ( p < 0.001 ) . Recurrent dislocation and pronounced limping were indications for revision surgery in eight of the sixty-one patients treated with robotic implantation compared with none of the seventy-eight ( excluding two with revision for infection ) treated with manual insertion ( p < 0.001 ) . Rupture of the gluteus medius tendon was observed during all of the revision operations . CONCLUSIONS The robotic-assisted technology had advantages in terms of preoperative planning and the accuracy of the intraoperative procedure . Disadvantages were the high revision rate ; the amount of muscle damage , which we believe was responsible for the higher dislocation rate ; and the longer duration of surgery . This technology must be further developed before its widespread usage can be justified 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 Background Patient-specific CT-based instrumentation may reduce implant malpositioning and improve alignment in TKA . However , it is not known whether this innovation is an advance that benefits patients . Questions / purpose sWe evaluated ( 1 ) the precision of  patient-specific TKA by comparing the incidence of outliers in postoperative alignment between TKAs using  patient-specific instruments  and TKAs using conventional instruments , and ( 2 ) the reliability of patient-specific instruments by intraoperatively investigating whether the surgery could be completed with patient-specific instruments alone . Methods In this r and omized controlled trial , we compared  patient-specific TKA instruments from one manufacturer ( n = 50 ) with conventional TKA instruments ( n = 50 ) . Postoperative hip-knee-ankle angles , femoral component rotation , and coronal and sagittal alignments of each component were measured . The validity of the patient-specific instrument was examined using cross-checking procedures with conventional instruments during the surgeries . When the procedure could not be completed accurately with patient-specific instruments , the procedure was converted to TKA using conventional instruments , and the frequency of this occurrence was tallied . Results Outliers in the hip-knee-ankle angle were comparable between groups ( 12 % in the patient-specific instrument group and 10 % in the conventional instrument group ) . Other parameters such as sagittal alignment and femoral component rotation did not differ in terms of outliers . Patient-specific guides were ab and oned in eight knees ( 16 % ) during the surgery because of malrotation of the femoral components and decreased slope of the tibia . Conclusions Accuracy was comparable between TKAs done with patient-specific instruments and those done with conventional instruments . However , the patient-specific instrument procedures had to be aborted frequently , incurring expenses that did not benefit patients .Level of Evidence Level II , therapeutic study . See Instructions for Authors for a complete description of levels of evidence
target: 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
background: 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 .