Alignment in total knee arthroplasty. A comparison of computer-assisted surgery with the conventional technique. Conventional versus computer-assisted technique for total knee arthroplasty: a minimum of 5-year follow-up of 200 patients in a prospective randomized comparative trial. Comparative study between computer assisted-navigation and conventional technique in minimally invasive surgery total knee arthroplasty, prospective control study. Robot-assisted total knee arthroplasty accurately restores the joint line and mechanical axis. A prospective randomised study. Functional outcome after computer-assisted versus conventional total knee arthroplasty: a randomized controlled study Clinical outcome using a ligament referencing technique in CAS versus conventional technique Conventional versus computer-navigated TKA: a prospective randomized study Navigated total knee arthroplasty: a radiological analysis of 42 randomised cases. Minimally invasive and computer-assisted total knee arthroplasty versus conventional technique: a prospective, randomized study Minimally Invasive Computer-Assisted Total Knee Arthroplasty Compared With Conventional Total Knee Arthroplasty: A Prospective 9-Year Follow-Up. Navigation of total knee arthroplasty: rotation of components and clinical results in a prospectively randomized study Comparison between patient-specific instruments and conventional instruments and computer navigation in total knee arthroplasty: a randomized controlled trial In-vivo alignment comparing patient specific instrumentation with both conventional and computer assisted surgery (CAS) instrumentation in total knee arthroplasty. On the outcome of computer-assisted total knee replacement. Computer-assisted total knee arthroplasty using mini midvastus or medial parapatellar approach technique Early experiences with robot-assisted total knee arthroplasty using the DigiMatch™ ROBODOC® surgical system. Short-Term Outcome after Computer-Assisted versus Conventional Total Knee Arthroplasty: A Randomised Controlled Trial
Restoration of neutral alignment of the leg is an important factor affecting the long-term results of total knee arthroplasty ( TKA ) . Recent developments in computer-assisted surgery have focused on systems for improving TKA . In a prospect i ve study two groups of 80 patients undergoing TKA had operations using either a computer-assisted navigation system or a conventional technique .  Alignment of the leg and the orientation of components were determined on post-operative long-leg coronal and lateral films . The mechanical axis of the leg was significantly better in the computer-assisted group ( 96 % , within + /- 3 degrees varus/valgus ) compared with the conventional group ( 78 % , within + /- 3 degrees varus/valgus ) . The coronal alignment of the femoral component was also more accurate in the computer-assisted group . Computer-assisted TKA gives a better correction of alignment of the leg and orientation of the components compared with the conventional technique . Potential benefits in the long-term outcome and functional improvement require further investigation In the literature , studies of computer-assisted total knee arthroplasty ( TKA )  after mid-term period are not conclusive and long-term data are rare . In a prospect i ve , r and omized , comparative study 100 conventional TKAs ( group REG ) were compared with 100 computer-assisted TKAs ( group NAV ) . Minimum follow-up was 5years . No difference in implant failure was found with 1.1 % in group NAV versus 4.6 % in group REG ( P=0.368 ) . Group NAV showed a significantly less mean deviation of mechanical limb axis ( P=0.015 ) , more TKAs ( 90 % versus 81 % in group REG ) were within 3 ° varus/valgus and a higher tibial slope and lateral distal femoral angle ( LDFA ) accuracy was found ( P≤0.034 ) . Clinical investigational parameters showed no differences ( P≥0.058 ) . Insall and HSS score total were also higher in group NAV ( P≤0.016 ) BACKGROUND Both Minimally Invasive surgery ( MIS ) and Computer-Assisted Surgery ( CAS ) are useful in Total Knee Arthroplasty ( TKA ) . Minimally invasive total knee arthroplasty was associated with decreased blood loss , shorter hospital stays , and increased range of motion .  Computer-assisted surgery in total knee arthroplasty was developed to improve the positioning of implants during surgery . OBJECTIVE To evaluate radiographic results relative to component position and limb alignment when using a navigation system compared with conventional technique in MIS-TKA . MATERIAL AND METHOD A prospect i ve control study was performed in 180 patients who underwent total knee arthroplasty by one surgeon . All patients were r and omly divided into two groups , Conventional and Navigation TKA .  Intra- , post-operative data , and postoperative limb alignment were recorded for comparison in both groups . RESULTS The postoperative mechanical axis was within 3 degrees of neutral mechanical alignment in 94 % of the navigation group and 87 % in conventional group ( p = 0.13 ) . Registration time of navigation group is 13.58 minutes . No statistical significant difference was found in tourniquet time and postoperative blood loss in both groups . CONCLUSION The use of navigation in total knee arthroplasty increases accuracy in limb and implants alignment , and does not increase complications and surgical times Robot-assisted Total Knee Arthroplasty ( TKA ) improves the accuracy and precision of component implantation and mechanical axis ( MA ) alignment . Joint-line restoration in robot-assisted TKA is not widely described and joint-line deviation of>5 mm results in mid-flexion instability and poor outcomes . We prospect ively r and omised 60 patients into two groups : 31 patients ( robot-assisted ) , 29 patients ( conventional ) .  No MA outliers ( > ±3 ° from neutral ) or notching was noted in the robot-assisted group as compared with 19.4 % ( P=0.049 ) and 10.3 % ( P=0.238 ) respectively in the conventional group . The robot-assisted group had 3.23 % joint-line outliers ( > 5 mm ) as compared to 20.6 % in the conventional group ( P=0.049 ) . Robot-assisted TKA produces similar short-term clinical outcomes when compared to conventional methods with reduction of MA alignment and joint-line deviation outliers Despite the frequent use of computer-assisted total knee arthroplasty ( TKA ) and better radiological results for coronal alignment reported in many studies , there is still no evidence of improved clinical outcomes when compared to conventional TKA . We compared alignment after navigated TKA and conventional TKA in 80 r and omized patients . Seventy three patients were available for physical and radiological examination at 20 month after surgery . Both groups showed similar Knee Society Score results , with medians of 89 points ( navigated 49–95 points , conventional 48–95 points , n.s . ) in the Knee Score and 70 points ( navigated 45–100 points , conventional 40–100 points , n.s . ) in the Function Score . The median improvement in the Knee Society Knee Score was 45 points ( −3 to 88 points ) in the navigated group and 35 points ( −13 to 62 points ) in the conventional group ( P = 0.03 ) , and the Knee Society Function Score improvement was 15 points ( −10 to 50 points ) in the navigated group versus 10 points ( −10 to 50 points ) in the conventional group ( n.s . ) . The current health state at follow-up using the EuroQuol question naire was similar in both groups , with medians of 67 points in the navigated group and 65 points in the conventional group . This investigation did show slightly greater functional improvement at short-term follow-up in the navigated TKA group . Longer follow-up will be required to assess the possible benefit of computer-assisted navigation Purpose Computer-assisted surgery ( CAS ) for total knee arthroplasty ( TKA ) has become increasingly common over the last decade . There are several reports including meta-analyses that show improved alignment , but the clinical results do not differ . Most of these studies have used a bone referencing technique to size and position the prosthesis . The question arises whether CAS has a more pronounced effect on strict ligamentous referencing TKAs . Methods We performed a prospect i ve cohort study comparing clinical outcome of navigated TKA ( 43 patients ) with that of conventional TKA ( 122 patients ) . Patients were assessed preoperatively , and 2 and 12 months postoperatively by an independent study nurse using vali date d patient-reported outcome tools as well as clinical examination . Results At 2 months , there was no difference between the two groups . However , after 12 months , CAS was associated with significantly less pain and stiffness , both at rest and during activities of daily living , as well as greater overall patient satisfaction . Conclusion The present study demonstrated that computer-navigated TKA significantly improves patient outcome scores such as WOMAC score ( P = 0.002 ) and Knee Society score ( P = 0.040 ) 1 year after surgery in using a ligament referencing technique . Furthermore , 91 % were extremely or very satisfied in the CAS TKA group versus 70 % after conventional TKA ( P = 0.007 ) Purpose The purpose of this study was to assess the midterm results of total knee arthroplasty ( TKA ) implanted with  a specific computer navigation system in a group of patients ( NAV ) and to assess the same prosthesis implanted with the conventional technique in another group ( CON ) ; we hypothesized that computer navigation surgery would improve implant alignment , functional scores and survival of the implant compared to the conventional technique . Methods From 2008 to 2009 , 225 patients were enrolled in the study and r and omly assigned in CON and NAV groups ; 240 consecutive mobile-bearing ultra-congruent score ( Amplitude , Valence , France ) TKAs were performed by a single surgeon , 117 using the conventional method and 123 using the computer-navigated approach .  Clinical outcome assessment was based on the Knee Society Score ( KSS ) , the Hospital for Special Surgery Knee Score and the Western Ontario Mac Master University Index score . Component survival was calculated by Kaplan – Meier analysis . Results Median follow-up was 6.4 years ( range 6–7 years ) . Two patients were lost to follow-up . No differences were seen between the two groups in age , sex , BMI and side of implantation . Three patients of CON group referred feelings of instability during walking , but clinical tests were all negative . NAV group showed statistical significant better KSS Score and wider ROM and fewer outliers from neutral mechanical axis , lateral distal femoral angle , medial proximal tibial angle and tibial slope in post-operative radiographic assessment . There was one case of early post-operative superficial infection ( caused by Staph . Aureus ) successfully treated with antibiotics . No mechanical loosening , mobile-bearing dislocation or patellofemoral complication was seen . At 7 years of follow-up , component survival in relation to the risk of aseptic loosening or other complications was 100 % . There were no implant revisions . Conclusion This study demonstrates superior accuracy in implant positioning and statistical significant better functional outcomes of computer-navigated TKA . Computer navigation for TKAs should be used routinely in primary implants . Level of evidence II The purpose of this study was to evaluate the use of a  navigation device  in a cohort of 42 total knee arthroplasties ( TKA ) . The patients were r and omised into two groups . Total knee arthroplasties performed using the conventional technique formed the control group ( 21 knees ) ; the experimental group included 21 knees performed with the aid of a computed navigation system .  Postoperative mean values for the various measurements showed no significant difference in component alignment . However , the range of individual measurements for coronal and sagittal plane positioning was smaller in the navigated group , in which there were no outliers . Rotational alignment was not different between the two groups . This confirms the advantages and limitations of navigated TKA presented in larger studies We conducted a prospect i ve , r and omized study to compare the short-term results of minimally invasive and computer-assisted total knee arthroplasty ( MICA-TKA ) with those of conventional total knee arthroplasty ( C-TKA ) for 12-month follow-up . A total of 87 subjects who met the inclusion and exclusion criteria of the study were prospect ively r and omized consecutively into two groups : the C-TKA group ( Group A , n = 44 ) and the MICA-TKA technique ( Group B , n = 43 ) . All the operations were performed by the same senior surgeon . Before surgery and at follow-up , patients were evaluated by the same observer . Tourniquet time as well as total blood loss was compared . Knee Society scores ( KSSs ) , Knee Society functional scores ( KSFSs ) , range of motion ( ROM ) , and radiographic results were assessed and reported preoperatively and at 12-month follow-up . Of these patients , 82 ( Group A 42 ; Group B 40 ) were available for 12-month evaluation . The two groups were found to be similar in terms of coronal mechanical axis . Similarly , the femoral rotational profile revealed that the prosthesis in Group A was implanted with similar internal rotation to Group B. The average blood loss in patients of Group B was significantly reduced as compared to patients of Group A. No significant difference was detected in terms of tourniquet time . Clinical results in Group B , with regard to ROMs and KSSs , as well as KSFSs were significantly superior to that in Group A. Based on the results obtained from this study , it is demonstrated that MICA-TKA leads to a similarly accurate restoration of leg alignment and component orientation compared to the C-TKA . Moreover , MICA-TKA produces superior clinical results to that of C-TKA . However , there is clearly a need for additional high- quality clinical trials with long-term follow-up to confirm the clinical benefits of MICA-TKA BACKGROUND Studies on minimally invasive computer-assisted total knee arthroplasty ( MICA-TKA ) have shown promising results , but are limited by short follow-up . The purpose of this study was to compare the midterm radiographic features and functional outcomes between patients who underwent MICA-TKA and conventional TKA .  METHODS A total of 108 patients who were r and omized to undergo MICA-TKA or conventional TKA during 2004 and 2005 were contacted for a prospect i ve follow-up review . Patients who were lost to contact , have passed away , or declined to participate in the study were excluded . Objective functional measurements and radiographs were obtained for assessment . RESULTS By the time of this study , 2 patients from the conventional group had undergone revision TKA , one due to infection and one due to aseptic loosening . A total of 67 patients ( 62.04 % ) were followed up for an average period of 9.07 years ( 8.51 - 9.61 years ) . At follow-up , functional scores were comparable between the 2 groups . No significant intergroup differences were found in mechanical knee alignment and component placement angle in the coronal views . No statistical or clinical significance were noticed in radiographic signs of component loosening . CONCLUSIONS MICA-TKA provided similar clinical , functional , and radiographic outcomes compared with conventional TKA after an average of 9-year follow-up . This technique can be used to exploit its short-term advantages without compromising midterm outcomes Background Navigation was introduced into  total knee arthroplasty ( TKA ) to improve accuracy of component position , function and survival of implants . This study was design ed to assess the outcome of navigated TKA in comparison with conventional implantation with the focus on rotational component position and clinical mid-term results . Methods In a prospect ively r and omized single-blinded approach , 90 patients with primary gonarthrosis were assigned to three different groups . Thirty patients each were assigned to NexGen LPS without and with navigation ( groups 1 and 2 ) , and 30 patients to navigation with the Stryker Scorpio PS ( group 3 ) . The navigation system used was the imageless Stryker KneeTrac , version 1.0 . Clinical outcome was assessed by a blinded observer applying the Knee Society Score ( KSS ) and a visual analogue scale ( VAS ) for pain . CT scans and radiographs were conducted prior to and 12 weeks after index surgery . Results Seventy-nine patients were available for clinical evaluation at 3 ± 0.4 years follow-up . Four implants had to be revised for early loosening or infection ( 4.4 % ) . Four patients had died and three patients were not able to follow the invitation for clinical assessment . Functional results in the KSS were significantly lower after navigated TKA . Operation time and incisions with navigation were significantly longer . Significantly less radiological outliers with navigation were found for coronal alignment of the femur , only . Conclusion In this series , no beneficial effect for navigation in TKA could be shown assessing clinical data , as functional results in the presented series seemed to be lower after first generation navigated TKA . The clinical mid- to long-term value of navigation remains to be evaluated in larger patient series or meta-analyses at longer follow-up . Trial registration numberDRKS 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 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 A number of studies have reported a significant improvement of the postoperative alignment , when computer-navigated total knee arthroplasty ( TKA )  was compared with conventional techniques . However , no studies are available on the functional and patient-relevant outcomes after computer-assisted knee replacement . In a prospect i ve , r and omized trial comparing 27 computer-assisted TKAs with 25 conventional implantations  , the Knee Society Score was used to assess functional status , and the WOMAC question naire was used to record the disease-specific , patient-relevant outcome . At a twelve-month follow-up no significant difference was detected between the two patient groups in either the scores or the number of complications and range of postoperative knee flexion . The results are in agreement with those reported in other studies on the effect of conventional TKA . With the patient group of this size it can be concluded that computer-navigated TKA gives short-term resuits comparable with those achieved by conventional methods of implantation Background Despite the growing evidence in the literature there is still a lack of consensus regarding the use of minimally invasive surgical technique ( MIS ) in total knee arthroplasty ( TKA ) . Methods A prospect i ve , r and omized , international multicentre trial including 69 patients was performed to compare computer-assisted TKA ( CAS-TKA ) using either mini-midvastus ( MIS group ) or st and ard medial parapatellar approach ( conventional group ) .  Patients from 3 centers ( Maastricht , Zwickau , Adelaide ) with end-stage osteoarthritis of the knee were r and omized to either an MIS group with dedicated instrumentation or a conventional group to receive cruciate retaining CAS-TKA without patella resurfacing .  The primary outcome was to compare post operative pain and range of motion ( ROM ) . The secondary outcome was to measure the duration of surgery , blood loss , chair rise test , quadriceps strength , anterior knee pain , Knee Society Score (KSS),WOMAC scores , mechanical leg axis and component alignment . Results Patients in the MIS group ( 3.97 ± 2.16 ) had significant more pain at 2 weeks than patients in the conventional group ( 2.77 ± 1.43 ) p = 0.003 . There was no significant difference in any of the other primary outcome parameters . Surgery time was significantly longer ( p < 0.001 ) and there were significantly higher blood loss ( p = 0.002 ) in the MIS group as compared to the conventional group . The difference of the mean mechanical leg alignment between the groups was not statistically significant ( –0.43 ° ( 95 % CI –1.50 – 0.64 ) ; p = 0.43).There was no significant difference of component alignment between the two surgical groups with respect to flexion/extension ( p = 0.269 ) , varus/valgus ( p = 0.653 ) or rotational alignment ( p = 0.485 ) of the femur component and varus valgus alignment ( p = 0.778 ) or posterior slope ( p = 0.164 ) of the tibial component . Conclusion There was no advantage of the MIS approach compared to a conventional approach CAS-TKA in any of the primary outcome measurements assessed , however the MIS approach was associated with longer surgical time and greater blood loss . MIS-TKA in combination with computer navigation is safe in terms of implant positioning . Trial registration number Clinical Trials.gov NCT02625311 8 December INTRODUCTION The use of robotics in total knee arthroplasty ( TKA ) has been shown to minimise human error , as well as improve the accuracy and precision of component implantation and mechanical axis alignment . The present study aim ed to demonstrate that robot-assisted TKA using ROBODOC ® is safe and capable of producing a consistent and accurate postoperative mechanical axis . METHODS We prospect ively recruited 27 consecutive patients who underwent robot-assisted TKA between May and December 2012 . Two patients were excluded from the study due to intraoperative technical problems with the robot .  Long-leg radiography and computed tomography were performed prior to surgery , and used for mechanical axis measurements and component sizing . DigiMatch ™ ROBODOC ® Surgical System software version 4.3.6 ( Curexo Technology Corp , Fremont , CA , USA ) was used in all cases to perform bone cuts in accordance with the preoperative plan . RESULTS The postoperative coronal mechanical alignment was within 3 degrees , with a mean alignment of -0.4 ± 1.7 degrees , confirming the accuracy of the preoperative surgical plan and bone cuts . The mean operating time was 96 ± 15 min , and preoperative planning yielded 100 % implant sizing accuracy . CONCLUSION Robotics has the potential to enable surgeons to consistently attain ideal postoperative alignment . The use of bone movement monitors and an integrated navigation system enhances the safety profile of ROBODOC ® by minimising errors . However , the role of the surgeon in TKA is still vital , as the surgeon is ultimately in charge of planning the surgery , its execution and ensuring soft tissue balance during TKA 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
The majority of adverse events associated with CNTKA were minor and comparable with those seen with conventional TKA .
Clinical outcomes were comparable between the two techniques , with longer-term follow-up suggesting that CNTKA provided no benefit over conventional TKA in terms of sustained functional improvements .
At present , it is unclear whether the significant improvements shown in radiological outcomes after CNTKA translate to measurable clinical benefits .
BACKGROUND Conventional total knee arthroplasty ( TKA ) and the more recently available computer-navigated total knee arthroplasty ( CNTKA ) use alternative methods to achieve correct limb alignment .
This systematic review was undertaken to assess the safety and effectiveness of CNTKA compared with conventional TKA .