title: On the outcome of computer-assisted total knee replacement. To Cement or Not? Two-Year Results of a Prospective, Randomized Study Comparing Cemented Vs. Cementless Total Knee Arthroplasty (TKA). Early experiences with robot-assisted total knee arthroplasty using the DigiMatch™ ROBODOC® surgical system. Sequential versus automated cutting guides in computer-assisted total knee arthroplasty. Mediolateral oversizing influences pain, function, and flexion after TKA Achieving Accurate Ligament Balancing Using Robotic-Assisted Unicompartmental Knee Arthroplasty Comparison of robotic-assisted and conventional manual implantation of a primary total knee arthroplasty. Minimally invasive and computer-assisted total knee arthroplasty versus conventional technique: a prospective, randomized study Computer assisted versus conventional cemented total knee prostheses alignment accuracy and micromotion of the tibial component Clinical outcome using a ligament referencing technique in CAS versus conventional technique Navigation of total knee arthroplasty: rotation of components and clinical results in a prospectively randomized study Midterm outcomes of electromagnetic computer-assisted navigation in minimally invasive total knee arthroplasty Comparison of robot-assisted and conventional total knee arthroplasty: A controlled cadaver study using multiparameter quantitative three-dimensional CT assessment of alignment Computer-assisted versus manual TKA: no difference in clinical or functional outcomes at 5-year follow-up. No difference between computer-assisted and conventional total knee arthroplasty: five-year results of a prospective randomised study Computer-navigated versus conventional total knee arthroplasty a prospective randomized trial. Robotic-assisted TKA Reduces Postoperative Alignment Outliers and Improves Gap Balance Compared to Conventional TKA Computer navigation versus conventional total knee replacement: no difference in functional results at two years. Computer-assisted gap balancing technique improves outcome in total knee arthroplasty, compared with conventional measured resection technique Coronal alignment correlates with outcome after total knee arthroplasty: five-year follow-up of a randomized controlled trial. Cemented versus cementless Oxford unicompartmental knee arthroplasty using radiostereometric analysis: a randomised controlled trial. Short-Term Outcome after Computer-Assisted versus Conventional Total Knee Arthroplasty: A Randomised Controlled Trial Computer navigation vs conventional total knee arthroplasty: five-year functional results of a prospective randomized trial. Clinical and radiologic outcomes of contemporary 3 techniques of TKA. Hands-on robotic unicompartmental knee replacement: a prospective, randomised controlled study of the acrobot system. Computer navigation results in less severe flexion contracture following total knee arthroplasty. Comparison of Outcome and Survival After Unicompartmental Knee Arthroplasty Between Navigation and Conventional Techniques With an Average 9-Year Follow-Up. Minimally invasive Oxford phase 3 unicompartmental knee replacement: results of 1000 cases. Influence of computer navigation on TKA revision rates Functional Outcome after Computer-Assisted Total Knee Arthroplasty Using Measured Resection versus Gap Balancing Techniques: A Randomised Controlled Study 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. Robot-assisted Total Knee Arthroplasty Comparison of radiographic alignment of imageless computer-assisted surgery vs conventional instrumentation in primary total knee arthroplasty. Technique and first clinical results of robot-assisted total knee replacement. Robot-assisted total knee arthroplasty accurately restores the joint line and mechanical axis. A prospective randomised study. Minimally Invasive Computer-Assisted Total Knee Arthroplasty Compared With Conventional Total Knee Arthroplasty: A Prospective 9-Year Follow-Up.
abstract: 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 The optimal mode of fixation in total knee arthroplasty ( TKA ) is a subject of debate . We enrolled 100 TKA patients r and omized to cemented or cementless fixation .  Knee Society Scores ( KSS ) , Oxford scores and pain visual analog scales ( VAS ) were collected pre-operatively and post-operatively . Two-year follow-up was obtained for 93 patients . The mean VAS trended higher for the cementless group at 4 months ( P=0.06 ) . At 2 years , the KSS functional scores , Oxford scores , and self-reported questions for satisfaction , less pain and better function were similar but the cemented group had higher KSS clinical scores ( 96.4 vs. 92.3 , P=0.03 ) . More radiolucencies were seen in cementless knees ( P<0.001 ) . The cementless group had one revision for instability and one cemented knee was revised for infection .  Cementless TKA showed equivalent survivorship ( revision for any reason as the endpoint ) compared to cemented TKA at this early follow-up . Close monitoring of radiolucencies is important with continued follow-up 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 The accuracy and efficiency of automated cutting guides in CAS systems have not been previously compared with conventional CAS techniques . Therefore , it is not yet clear if these more advanced technologies are warranted . We hypothesized that a novel automated cutting guide with CAS for total knee arthroplasty would be more efficient and more accurate than conventional navigation with sequential cutting blocks . Twelve cadaver legs were used in total . Each leg was r and omly assigned to either an automated guide positioning or a conventional freeh and computer-navigated guide positioning . The guide positions postosseous fixation and the final bone-cut surfaces were digitized and compared to the targeted cutting planes . The final location of the impacted trial implant was also digitized and compared to the planned implant location . The time for each step and the total time taken to prepare the femur were measured for both groups . The mean femoral preparation time was shorter with the automated cutting guide than the conventional method ( 5.5 min versus 13.8 min , p<0.001 ) . The average deviation in the final bone resections from the planned resections was significantly lower for the automated cutting guide in the frontal/rotational plane ( 0.55 ° versus 1.1 ° ) , sagittal plane ( 0.75 ° versus 2.0 ° ) , and cut height direction ( 0.56 mm versus 1.6 mm ) . Therefore , based on these results , we concluded that automated cutting-guide positioning result ed in more efficient and more accurate femoral cuts in comparison to the conventional navigation method in a cadaveric model Purpose Manufacturers of total knee arthroplasty ( TKA )  have introduced narrower femurs to improve bone-implant fit . However , few studies have reported the clinical consequences of mediolateral oversizing . Our hypothesis was that component oversizing negatively influences the results after TKA . Methods One hundred and twelve prospect ively followed patients with 114 consecutive TKA ( 64 females and 50 males ) were retrospectively assessed . The mean age of the patients was 72 years ( range , 56 to 85 years ) . The dimensions of the femur and tibia were measured on a preoperative CT-scan and were compared with those of the implanted TKA . The influence of size variation on the clinical outcomes 1 year after surgery was assessed . Results Mediolateral overhang was observed in at least one area in 66 % of the femurs ( 84 % in females and 54 % in males ) and 61 % of the tibia ( 81 % in females and 40 % in males ) . Twenty-two patients presented no overhang in any area and 16 had overhang in all studied zones . The increase in the Pain and KOOS scores were 43 ± 21 and 36 ± 18 in the patients without overhang and 31 ± 19 and 25 ± 13 in patients with overhang ( p = 0.033 ; p = 0.032 ) . Knee flexion was 127 ° ± 7 and 121 ° ± 11 , respectively . Regression and latent class analysis showed a significant negative correlation between overall oversizing and overall outcome . Conclusions This study confirms that oversizing may lead to worse clinical results in TKA . The clinical consequences are that surgeons should pay attention not to oversize implants during implantation nd that oversizing should be ruled out in case of so called unexplained pain . Level of evidence IV Unicompartmental knee arthroplasty ( UKA ) allows replacement of a single compartment in patients with limited disease . However , UKA is technically challenging and relies on accurate component positioning and restoration of natural knee kinematics . This study examined the accuracy of dynamic , real-time ligament balancing  using a robotic-assisted UKA system . Surgical data obtained from the computer system were prospect ively collected from 51 patients ( 52 knees ) undergoing robotic-assisted medial UKA by a single surgeon .  Dynamic ligament balancing of the knee was obtained under valgus stress prior to component implantation and then compared to final ligament balance with the components in place . Ligament balancing was accurate up to 0.53 mm compared to the preoperative plan , with 83 % of cases within 1 mm at 0 ° , 30 ° , 60 ° , 90 ° , and 110 ° of flexion . Ligamentous laxity of 1.31 ± 0.13 mm at 30 ° of flexion was corrected successfully to 0.78 ± 0.17 mm ( P < 0.05 ) . Robotic-assisted UKA allows accurate and precise reproduction of a surgical balance plan using dynamic , real-time soft-tissue balancing to help restore natural knee kinematics , potentially improving implant survival and functional outcomes This study was aim ed to compare robotic-assisted implantation of a total knee arthroplasty with conventional manual implantation . We controlled , r and omized , and review ed 72 patients for total knee arthroplasty assigned to undergo either conventional manual implantation ( excluding navigation-assisted implantation cases ) of a Zimmer LPS prosthesis ( Zimmer , Warsaw , Ind ) ( 30 patients : group 1 ) or robotic-assisted implantation of such a prosthesis ( 32 patients : group 2 ) . The femoral flexion angle ( gamma angle ) and tibial angle ( delta angle ) in the lateral x-ray of group 1 were 4.19 + /- 3.28 degrees and 89.7 + /- 1.7 degrees , and those of group 2 were 0.17 + /- 0.65 degrees and 85.5 + /- 0.92 degrees . The major complications were from improper small skin incision during a constraint attempt of minimally invasive surgery and during bulk fixation frame pins insertion . Robotic-assisted technology had definite advantages in terms of preoperative planning , accuracy of the intraoperative procedure , and postoperative follow-up , especially in the femoral flexion angle ( gamma angle ) and tibial flexion angle ( delta angle ) in the lateral x-ray , and in the femoral flexion angle ( alpha angle ) in the anteroposterior x-ray . But a disadvantage was the high complication rate in early stage 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 We evaluated the influence of CT-free or CT-based computer assisted orthopaedic surgery ( CAOS ) on the alignment of total knee prostheses ( TK ) and micromotion of tibial components . This r and omised study compared 19 CT-free , 17 CT-based CAOS TK , and a matched control group of 21 conventionally placed TK .  Using Roentgen stereophotogrammetric analysis ( RSA ) the migration was measured . The alignment and component positions were measured on radiographs . No significant difference in leg and tibial component alignment was present between the three groups . A significant difference was found for micromotion in subsidence , with the conventional group having a mean of 0.16 mm , compared to the CT-free group at 0.01 mm and the CT-based group at −0.05 mm . No clinical significant difference in alignment was found between CAOS and conventionally operated TK . More subsidence of the tibial component was seen in the conventional group compared to both CAOS groups at two year follow-up . RésuméBut de l'étude : Evaluer l'influence de la navigation avec ou sans scanner sur l'alignement des prothèses totales du genou et sur la micromobilité du composant tibial . Matériel et méthode : nous avons réalisé une étude r and omisée comparant 19 prothèses naviguées sans scanner , 17 prothèses naviguées avec scanner , croisées avec un groupe contrôle de 21 patients avec mise en place d'une prothèse par voie conventionnelle . Nous avons utilisé la méthode RSA pour mesurer la migration . L'alignement et les composants étaient mesurés sur les radiographies . Résultats : il n'y a pas de différence significative au niveau de l'alignement des composants pour les trois groupes , par contre il existe une différence significative en ce qui concerne la migration . Dans le groupe conventionnel celle-ci est d'environ 0,16 mm , 0,01 mm dans le groupe navigation sans scanner et 0,05 mm dans le groupe navigation avec scanner . Conclusion : il n'y a pas de différence significative dans l'alignement des prothèses totales du genou lors de la mise en place d'une prothèse totale avec ou sans navigation par contre , il existe une micromobilité avec petite migration du composant tibial si l'on compare le groupe conventionnel avec les groupes navigués 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 ) 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 Background A combination of two emerging technologies , computer-assisted navigation and minimally invasive surgery , in total knee arthroplasty has gained increasing interests from orthopedic surgeons around the world . To date , there has never been any midterm study for clinical and radiographic outcomes from using an electromagnetic computer-assisted navigation system . In this study , we aim ed to systematic ally compare clinical and radiographic outcomes of minimally invasive surgery in total knee arthroplasty ( MIS-TKA ) performed with and without electromagnetic computer-assisted navigation at immediate and midterm follow-ups . Methods A total of 151 patients ( 160 knees ) who underwent MIS-TKA were r and omized to be operated with electromagnetic computer-assisted navigation ( group I : 75 patients , 80 knees ) or without the navigation ( group II : 76 patients , 80 knees ) . The clinical and radiographic outcomes of immediate , 6-week postoperative follow-up and average 6.1-year follow-up were compared . Results On immediate , 6-week postoperative follow-up , clinical and radiographic outcomes did not reveal any difference between the two groups except for the fact that the operative time was longer in the navigation group . On 6.1-year follow-up , a total of 58 patients ( 63 knees ) from group I and 58 patients ( 61 knees ) from group II were reevaluated . There were no significant differences in clinical and radiographic loosening and in complications between the two groups . Conclusion In this study , no significant differences of clinical and radiographic outcomes were found for immediate and midterm follow-ups of MIS-TKA performed with and without electromagnetic computer-assisted navigation except for the additional operating time in the navigation group Introduction : A functional total knee replacement has to be well aligned , which implies that it should lie along the mechanical axis and in the correct axial and rotational planes . Incorrect alignment will lead to abnormal wear , early mechanical loosening , and patellofemoral problems . There has been increased interest of late in total knee arthroplasty with robotic assistance . This study was conducted to determine whether robot-assisted total knee arthroplasty is superior to the conventional surgical method with regard to the precision of implant positioning . Material s and Methods : Twenty knee replacements , comprising ten robot-assisted procedures and ten conventional operations , were performed on ten cadavers . Two experienced surgeons performed the surgeries . Both procedures on each cadaver were performed by the same surgeon . The choice of which procedure was to be performed first was r and omized . Following implantation of the prosthesis , the mechanical axis deviation , femoral coronal angle , tibial coronal angle , femoral sagittal angle , tibial sagittal angle , and femoral rotational alignment were measured via 3D CT scanning . These variables were then compared with the preoperatively planned values . Results : In the knees that underwent robot-assisted surgery , the mechanical axis deviation ranged from −1.94 ° to 2.13 ° ( mean : −0.21 ° ) , the femoral coronal angle from 88.08 ° to 90.99 ° ( mean : 89.81 ° ) , the tibial coronal angle from 89.01 ° to 92.36 ° ( mean : 90.42 ° ) , the tibial sagittal angle from 81.72 ° to 86.24 ° ( mean : 83.20 ° ) , and the femoral rotational alignment from 0.02 ° to 1.15 ° ( mean : 0.52 ° ) in relation to the transepicondylar axis . In the knees that underwent conventional surgery  , the mechanical axis deviation ranged from −3.19 ° to 3.84 ° ( mean : −0.48 ° ) , the femoral coronal angle from 88.36 ° to 92.29 ° ( mean : 90.50 ° ) , the tibial coronal angle from 88.15 ° to 91.51 ° ( mean : 89.83 ° ) , the tibial sagittal angle from 80.06 ° to 87.34 ° ( mean : 84.50 ° ) , and the femoral rotational alignment from 0.32 ° to 4.13 ° ( mean : 2.76 ° ) in relation to the transepicondylar axis . In the conventional knee replacement group , there were two instances of outliers outside the range of 3 ° varus/valgus for the mechanical axis deviation . The robot-assisted knee replacements showed significantly superior femoral rotational alignment results compared with conventional surgery ( p = 0.006 ) . There was no statistically significant difference between robot-assisted and conventional total knee arthroplasty with regard to the other variables . All the measurements showed high intra-observer and inter-observer reliability . Conclusion : Robot-assisted total knee arthroplasty showed excellent precision in the sagittal and coronal planes of the 3D CT scan . In particular , the robot-assisted technique showed better accuracy in femoral rotational alignment compared to the conventional surgery , despite the fact that the surgeons who performed the operations were more experienced and familiar with the conventional method than with robot-assisted surgery . It can thus be concluded that robot-assisted total knee arthroplasty is superior to conventional total knee arthroplasty The purpose of this study was to determine whether differences in clinical , functional , or radiographic outcomes existed at 5-year follow-up between patients who underwent computer-assisted or manual total knee arthroplasty ( TKA ) . Seventy-eight consecutive TKAs were performed by a single surgeon who had extensive experience performing computer-assisted and manual TKA .  The manual group ( n=40 ) and computer-assisted group ( n=38 ) were similar with regard to age , sex , diagnosis , body mass index , surgical technique , implants , perioperative management , Knee Society scores , and anteroposterior mechanical axis . Sixty-three ( manual group , n=34 ; computer-assisted group , n=29 ) patients were available for final follow-up . At 5-year follow-up , no statistically significant differences were found in Knee Society knee score ( P=.289 ) , function score ( P=.272 ) , range of motion ( P=.284 ) , pain score ( P=.432 ) , or UCLA activity score ( P=.109 ) between the 2 groups . Postoperative radiographs showed a significant difference in the mechanical axis ( P=.004 ) between the 2 groups ; however , both groups achieved a neutral mechanical axis of ±3 ° ( computer-assisted group mean , 2.0 ° ; manual group mean , -0.24 ° ).When TKA was performed by an experienced surgeon , no significant difference was identified at 5-year follow-up between patients who underwent computer-assisted vs manual TKA Purpose The use of computer-assisted surgery ( CAS ) in total knee arthroplasty ( TKA ) results in better limb and implant alignment compared to conventional TKA ; however , it is unclear whether this translates to better mid- to long-term clinical outcome . This prospect i ve r and omised study comparing CAS and conventional TKA reports the functional and patient perceived outcomes at a follow-up of 5 years . The hypothesis was that there would be a difference in functional outcome or quality of life after mid-term follow-up . Methods Sixty-seven patients were available for physical and radiological examination at 5 years .  The Knee Society Score ( KSS ) was used to describe functional outcome and the Euroquol question naire for quality of life . Results The mean total KSS for the CAS group improved from 91.1 ( SD 22.3 ) points preoperatively to 157.4 ( SD 21.9 ) and 150.2 ( SD 30.4 ) points at 2 and 5 years , respectively . In the conventional group , the mean total KSS was 99.6 ( SD 18.6 ) points preoperatively and 151.1 ( SD 26.0 ) and 149.0 ( SD 28.0 ) points at 2 and 5 years , respectively . The mean quality of life score improved from 48.2 ( SD 16.5 ) points preoperatively to 67.4 ( SD 16.3 ) and 66.8 ( SD 22.2 ) points at 2 and 5 years in the CAS group , and from 52.2 ( SD 17.1 ) points preoperatively to 65.6 ( SD 14.6 ) and 61.7 ( SD 19.3 ) points at 2 and 5 years , respectively , in the conventional TKA group . These differences were not statistically significant . There were radiolucent lines up to 2 mm in 11 knees ( four CAS , seven conventional ) , but there were no changes in implant position . Conclusions There were no significant differences in functional or patient perceived outcome after mid-term follow-up in this study .Level of evidence BACKGROUND The literature lacks studies that confirm whether the improved radiographic alignment that can be achieved with computer-navigated total knee arthroplasty improves patients ’ activities of daily living or the durability of total knee prostheses . The purpose of this study was to determine whether computer-navigated total knee arthroplasty improves the clinical function , alignment , and survivorship of the components . METHODS We prospect ively compared the results of 520 patients with osteoarthritis who underwent computer-navigated total knee arthroplasty for one knee and conventional total knee arthroplasty for the other . The assignment of the knee to navigation or not was done r and omly . There were 452 women ( 904 knees ) and sixty-eight men ( 136 knees ) with a mean age of sixty-eight years ( range , forty-nine to eighty-eight years ) at the time of the index arthroplasty . The mean follow-up period was 10.8 years ( range , ten to twelve years ) . The patients were assessed clinical ly and radiographically with the rating system of the Knee Society and with the Western Ontario and McMaster Universities Osteoarthritis Index ( WOMAC ) score at three months , one year , and annually thereafter . RESULTS Total knee scores , knee function scores , pain scores , WOMAC scores , knee motion , and activity scores did not show statistically significant differences between the two groups preoperatively or at the time of the final follow-up . Alignment and the survivorship of the components were not significantly different between the two groups . The Kaplan-Meier survivorship with revision as the end point at 10.8 years was 98.8 % ( 95 % confidence interval [ CI ] , 0.96 to 1.00 ) in the computernavigated total knee arthroplasty group and 99.2 % ( 95 % CI , 0.96 to 1.00 ) in the conventional total knee arthroplasty group . CONCLUSIONS Our data demonstrated no difference in clinical function or alignment and survivorship of the components between the knees that underwent computer-navigated total knee arthroplasty and those that underwent conventional total knee arthroplasty Background Several studies have shown mechanical alignment influences the outcome of TKA . Robotic systems have been developed to improve the precision and accuracy of achieving component position and mechanical alignment . Questions / purpose sWe determined whether robotic-assisted implantation for TKA ( 1 ) improved clinical outcome ; ( 2 ) improved mechanical axis alignment and implant inclination in the coronal and sagittal planes ; ( 3 ) improved the balance ( flexion and extension gaps ) ; and ( 4 ) reduced complications , postoperative drainage , and operative time when compared to conventionally implanted TKA over an intermediate-term ( minimum 3-year ) followup period . Methods We prospect ively r and omized 100 patients who underwent unilateral TKA into one of two groups : 50 using a robotic-assisted procedure and 50 using conventional manual techniques .  Outcome variables considered were postoperative ROM , WOMAC scores , Hospital for Special Surgery ( HSS ) knee scores , mechanical axis alignment , flexion/extension gap balance , complications , postoperative drainage , and operative time . Minimum followup was 41 months ( mean , 65 months ; range , 41–81 months ) . Results There were no differences in postoperative ROM , WOMAC scores , and HSS knee scores . The robotic-assisted group result ed in no mechanical axis outliers ( > ± 3 ° from neutral ) compared to 24 % in the conventional group . There were fewer robotic-assisted knees where the flexion gap exceeded the extension gap by 2 mm . The robotic-assisted procedures took an average of 25 minutes longer than the conventional procedures but had less postoperative blood drainage . There were no differences in complications between groups . Conclusions Robotic-assisted TKA appears to reduce the number of mechanical axis alignment outliers and improve the ability to achieve flexion-extension gap balance , without any differences in clinical scores or complications when compared to conventional manual techniques . Level of Evidence Level I , therapeutic study . See Instructions for Authors for a complete description of levels of evidence We previously compared the component alignment in  total knee replacement  using a computer-navigated technique with a conventional jig-based method . We r and omly allocated 71 patients to undergo either computer-navigated or conventional replacement .  An improved alignment was seen in the computer-navigated group . The patients were then followed up post-operatively for two years , using the Knee Society score , the Short Form-36 health survey , the Western Ontario and McMaster Universities osteoarthritis index , the Bartlett Patellar pain question naire and the Oxford knee score , to assess functional outcome . At two years post-operatively 60 patients were available for assessment , 30 in each group and 62 patients completed a postal survey . No patient in either group had undergone revision . All variables were analysed for differences between the groups either by Student 's t-test or the Mann-Whitney U test . Differences between the two groups did not reach significance for any of the outcome measures at any time point . At two years postoperatively , the frequency of mild to severe anterior pain was not significantly different ( p = 0.818 ) , varying between 44 % ( 14 ) for the computer-navigated group , and 47 % ( 14 ) for the conventionally-replaced group . The Bartlett Patellar score and the Oxford knee score were also not significantly different ( t-test p = 0.161 and p = 0.607 , respectively ) . The clinical outcome of the patients with a computer-navigated knee replacement appears to be no different to that of a more conventional jig-based technique at two years post-operatively , despite the better alignment achieved with computer-navigated surgery Purpose The objective of this prospect i ve study was to compare the functional outcome of conventional measured resection technique and computer-assisted gap balancing technique in TKA . Methods 140 patients were r and omized into two groups . The conventional measured resection technique without computer navigation was performed in Group 1 and the computer-assisted gap balancing technique in Group 2 . Range of motion , clinical laxity assessment with KT-1000 arthrometer , postoperative radiological films and various functional knee scores were documented at 6 months and 2 years . Results At 2 years , there were significantly more patients ( five patients , 7 % ) in the Group 1 with flexion contractures of more than 5 ° ( P = 0.05 ) . There were significantly more outliers in the Group 1 ( eight patients , 11 % ) , who demonstrated anterior tibial translation > 5 mm , than Group 2 ( two patients , 3 % ) ( P = 0.041 ) . The total excursion at 20 ° was significantly higher in Group 1 at 6 months ( P = 0.012 ) and after 2 years ( P = 0.031 ) . Group 2 was able to demonstrate significantly better limb alignment with fewer outliers ( more than 3 ° varus/valgus ) than Group 1 . At 6-month follow-up , Group 2 demonstrated better outcomes in Function Score ( P = 0.040 ) and Total Oxford Score ( P = 0.031 ) . At 2-year review , Group 2 had better outcome in the Total Oxford Score ( 0.030 ) . Conclusion Computer-assisted gap balancing technique was able to achieve more precise soft tissue balance and restoration of limb alignment with better knee scores as compared to the conventional measured resection technique in total knee arthroplasty . Level of evidence In a prospect i ve r and omized control trial comparing computer-assisted vs conventional total knee arthroplasty  , we previously reported that patients with coronal alignment within 3 ° of neutral had superior international knee society and Short-Form 12 ( SF-12 ) physical scores at 6 weeks , 3 months , 6 months , and 12 months after surgery . Computer-assisted total knee arthroplasty achieved greater accuracy in implant alignment , and this correlated with better knee function and quality of life . At 5 years , 90 of 111 patients assessed in our original study were review ed . Coronal alignment within 3 ° of neutral continued to be correlated with superior International Knee Society and SF-12 scores . Coronal alignment greater than 3 ° was associated with a significant decline in SF-12 mental health scores The most common reasons for revision of unicompartmental knee arthroplasty ( UKA ) are loosening and pain . Cementless components may reduce the revision rate . The aim of this study was to compare the fixation and clinical outcome of cementless and cemented Oxford UKAs .  A total of 43 patients were r and omised to receive either a cemented or a cementless Oxford UKA and were followed for two years with radiostereometric analysis ( RSA ) , radiographs aligned with the bone-implant interfaces and clinical scores . The femoral components migrated significantly during the first year ( mean 0.2 mm ) but not during the second . There was no significant difference in the extent of migration between cemented and cementless femoral components in either the first or the second year . In the first year the cementless tibial components  subsided significantly more than the cemented components ( mean 0.28 mm ( sd 0.17 ) vs. 0.09 mm ( sd 0.19 mm ) ) . In the second year , although there was a small amount of subsidence ( mean 0.05 mm ) there was no significant difference ( p = 0.92 ) between cemented and cementless tibial components . There were no femoral radiolucencies . Tibial radiolucencies were narrow ( < 1 mm ) and were significantly ( p = 0.02 ) less common with cementless ( 6 of 21 ) than cemented ( 13 of 21 ) components at two years . There were no complete radiolucencies with cementless components , whereas five of 21 ( 24 % ) cemented components had complete radiolucencies . The clinical scores at two years were not significantly different ( p = 0.20 ) . As second-year migration is predictive of subsequent loosening , and as radiolucency is suggestive of reduced implant-bone contact , these data suggest that fixation of the cementless components is at least as good as , if not better than , that of cemented devices 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 Seventy-one patients were r and omly allocated to undergo either computer-navigated or conventional arthroplasty . A statistically significant improvement in alignment was seen in the computer-navigated cohort . Five-year functional outcome was assessed using the Knee Society , Short Form-36 , Western Ontario and McMaster Universities Osteoarthritis Index , and a patient satisfaction score . At 5 years , 46 patients were available for assessment ( 24 navigated and 22 conventional knees ) . No patients had undergone revision . No statistically significant difference was seen in any component of any measure of outcome between navigated and conventional cohorts . Longitudinal data showed function to be well maintained with no difference in functional score between 2 and 5 years in either cohort . Despite achieving better alignment , 5 years postoperatively , the functional outcome with computer-navigated knee arthroplasty appears to be no different to that implanted using a conventional jig-based technique This report compares the radiologic and early clinical results of total knee arthroplasty ( TKA ) performed by the same surgeon using 3 techniques . In this prospect i ve study , 75 knees were r and omized to conventional technique  ( 25 knees ) , image-free navigation system  ( 25 knees ) , or minimally invasive surgery ( MIS ) ( 25 knees ) . Age range of the 43 women ( 65 knees ) and 5 men ( 10 knees ) was 58 to 81 years . Posterior stabilized knee prosthesis was used in all patients . Data was collected according to Knee Society System for radiologic evaluation of x-rays . Knee Society clinical ( KS-C ) and functional knee scores were measured preoperatively and at 6 weeks , 3 months , 6 months , 1 year , and 2 years . The postoperative KS-C was not statistically better in the MIS group ( mean , 88 ± 11.5 ; range , 70 - 100 ) than the conventional ( mean , 85.9 ± 7.8 ; range , 74 - 94 ) ( P=.68 ) or navigation group ( mean , 85 ± 11 ; range , 63 - 100 ) ( P=.59 ) . Mean postoperative delta ( mechanical axis ) angle was significantly different ( P=.014 ) : 2.38 ° in the conventional group ( SD=2.88 ° ; 95 % CI , 1.19 ° -3.57 ° ; range , -1.59 ° to 6.86 ° ) , 0.61 ° in the navigation group ( SD=2.07 ° ; 95 % CI , -0.24 ° to 1.46 ° ; range , -2.07 ° to 4.25 ° ) , and 4.25 ° in the MIS group ( SD=6.52 ° ; 95 % CI , 1.56 ° -6.94 ° ; range , -6.72 ° to 15.60 ° ) . Significant difference could be elicited between navigation-assisted and MIS groups , with navigation-assisted surgery providing more accurate alignment of the mechanical axis ( P=.014 ) . Of the three techniques , navigation-assisted surgery gives superior prosthesis alignment and promising longevity of TKA We performed a prospect i ve , r and omised controlled trial of unicompartmental knee arthroplasty comparing the performance of the Acrobot system with conventional surgery . A total of 27 patients ( 28 knees ) awaiting unicompartmental knee arthroplasty were r and omly allocated to have the operation performed conventionally or with the assistance of the Acrobot . The primary outcome measurement was the angle of tibiofemoral alignment in the coronal plane , measured by CT . Other secondary parameters were evaluated and are reported . All of the Acrobot group had tibiofemoral alignment in the coronal plane within 2 degrees of the planned position , while only 40 % of the conventional group achieved this level of accuracy . While the operations took longer , no adverse effects were noted , and there was a trend towards improvement in performance with increasing accuracy based on the Western Ontario and McMaster Universities Osteoarthritis Index and American Knee Society scores at six weeks and three months . The Acrobot device allows the surgeon to reproduce a pre-operative plan more reliably than is possible using conventional techniques which may have clinical advantages We compared  postoperative flexion contracture  in  navigated total knee arthroplasty ( TKA ) versus  conventional TKA .  Two groups ( Group 1 :  conventional  , Group 2 : navigated ) of 235 consecutive patients matched for age and gender were retrospectively compared . Range of motion , mechanical axes , Knee Society Scores , Oxford Knee Scores and Short Form-36 ® ( SF-36 ) scores were collected prospect ively and compared preoperatively and at 2years following TKA . At 2years , patients who underwent navigated TKA averaged significantly lesser flexion contracture of 1 degree compared to 6 degrees in patients who underwent conventional TKA . There were a significantly larger proportion of outliers in the conventional group . Computer navigation results in less severe flexion contracture and less frequent flexion contracture of more than 5 degrees as compared to conventional techniques BACKGROUND Unicompartmental knee arthroplasty(UKA ) has become a treatment of choice for many patients with isolated unicomparmental arthritis due to its specific advantages over total knee arthroplasty , but few studies have compared conventional and navigational UKA with similar instrumentation on mid- to long-term results . We investigated whether the use of imageless navigation can improve implant positioning and clinical outcomes of UKA at a long-term follow-up compared to the conventional technique . METHODS We prospect ively studied clinical and radiological results in 68 patients with an average age of 64.0 years ( range , 50 to 81 years ) who received UKA between January 2003 and December 2005 using the conventional or navigational technique .  Clinical evaluations were performed preoperatively and the last follow-up included knee range of motion , Hospital for Special Surgery ( HSS ) scores , Western Ontario and McMaster Universities Osteoarthritis Index ( WOMAC ) scores and Visual Analogue Scale ( VAS ) pain score . For radiologic evaluation , the mechanical alignment of the lower limb was measured using mechanical femoro-tibial angle ( mFTA ) and Kennedy protocol . RESULTS After an average 9-year follow-up ( range , 7.4 to 10.8 years ) , the navigation group showed better coronal alignments of the components , fewer radiological outliers and better clinical scores , but similar estimated 10-year prosthesis survival rates . CONCLUSION This study indicates that the use of navigation significantly contributes to the desired mechanical axis and improved component placement as compared to the conventional technique . LEVEL OF EVIDENCE Prospect i ve comparative study , Level III This prospect i ve study describes the outcome of the first 1000 phase 3 Oxford medial unicompartmental knee replacements ( UKRs ) implanted using a minimally invasive surgical approach for the recommended indications by two surgeons and followed up independently . The mean follow-up was 5.6 years ( 1 to 11 ) with 547 knees having a minimum follow-up of five years . At five years their mean Oxford knee score was 41.3 ( sd 7.2 ) , the mean American Knee Society Objective Score 86.4 ( sd 13.4 ) , mean American Knee Society Functional Score 86.1 ( sd 16.6 ) , mean Tegner activity score 2.8 ( sd 1.1 ) . For the entire cohort , the mean maximum flexion was 130 ° at the time of final review . The incidence of implant-related re-operations was 2.9 % ; of these 29 re-operations two were revisions requiring revision knee replacement components with stems and wedges , 17 were conversions to a primary total knee replacement , six were open reductions for dislocation of the bearing , three were secondary lateral UKRs and one was revision of a tibial component . The most common reason for further surgical intervention was progression of arthritis in the lateral compartment ( 0.9 % ) , followed by dislocation of the bearing ( 0.6 % ) and revision for unexplained pain ( 0.6 % ) . If all implant-related re-operations are considered failures , the ten-year survival rate was 96 % ( 95 % confidence interval , 92.5 to 99.5 ) . If only revisions requiring revision components are considered failures the ten-year survival rate is 99.8 % ( confidence interval 99 to 100 ) . This is the largest published series of  UKRs  implanted through a minimally invasive surgical approach and with ten-year survival data . The survival rates are similar to those obtained with a st and ard open approach whereas the function is better . This demonstrates the effectiveness and safety of a minimally invasive surgical approach for implanting the Oxford UKR Purpose We performed this study to determine whether the use of imageless navigation reduces revision rates after total knee arthroplasty ( TKA ) . Methods Data of 1,121 consecutive primary TKA with a follow-up of one to six years were retrospectively analysed . Following the conversion of the st and ard technique from conventional to navigated procedures , these data included the last 342 conventional and first 779 navigated procedures performed in our clinic . Demographic and perioperative covariates were recorded . All patients were asked by post to report instances of revisions . Results Data of 1,054 patients ( 94 % ) were complete . Mean follow-up was 3.9 years for conventional and 2.4 years for navigated operations .  Cumulative revision rate averaged 4.7 % for conventional and 2.3 % for navigated procedures . Cox ’s proportional hazard model was used to assess the effect of covariates on survival , result ing in significantly lower revision rates for older patients ( p < 0.001 ) and for the navigated technique ( p = 0.012 ) . The reduced revision rate for navigated operations was mainly caused by a significantly reduced rate of aseptic implant loosening ( 1.9 % vs. 0.1 % , p = 0.024 ) . Conclusions Our study showed lower revision rates when computer navigation was used . However , due to the retrospective uncontrolled design , further prospect i ve trials will be necessary to further evaluate this effect Purpose . To compare the 2-year outcome of  total knee arthroplasty ( TKA ) using the measured resection versus the gap balancing techniques . Methods . 21 men and 31 women aged 41 to 89 ( mean , 73 ) years who underwent primary TKA by a single surgeon for osteoarthritis and had an American Society of Anesthesiologists I or II physical status were prospect ively studied . Patients were r and omised to undergo computer-assisted TKA using the measured resection technique ( n=26 ) or the gap balancing technique ( n=26 ) . At the 2-year followup , patients were assessed by a single orthopaedic registrar blinded to the type of surgery using the Knee Society score ( KSS ) , functional Knee Society score ( FKSS ) , and revised Oxford Knee score ( ROKS ) . Results . In the measured resection group , the mean KSS , FKSS , and ROKS increased from 34.3 , 48 , and 21 to 85.9 , 89.6 , and 36.5 , respectively . In the gap balancing group , the respective scores increased from 35.4 , 50 , and 22.5 to 89.1 , 92.4 , and 40.6 . Postoperative with the gap balancing technique ; the respective p values were 0.46 , 0.44 , and 0.12 . Conclusion . Improvements in the knee scores were comparable with the 2 techniques 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 ) Increasing evidence suggests performing  total knee arthroplasty  using computer navigation can lead to more accurate surgical positioning of the components and knee alignment compared to a conventional operating technique without computer assistance . The use of robotic technology could theoretically take this accuracy one level further because it uses navigation in combination with ultimate mechanical precision , which could eliminate or reduce the inevitable margin of error during mechanical preparation of the bony cuts of total knee arthroplasty by the surgeon . We prospect ively followed 25 consecutive cases using an active surgical robot . The minimum followup was 5.1 years ( mean , 5.5 years ; range , 5.1 - 5.8 years ) . Our results demonstrate excellent implant positioning and alignment was achieved within the 1 ° error of neutral alignment in all three planes in all cases . Despite this technical precision , the excessive operating time required for the robotic implantation , the technical complexity of the system , and the extremely high operational costs have led us to ab and on this procedure and direct our interest more toward smart semiactive robotic systems . Level of Evidence : Level IV , therapeutic study . See the Guidelines for Authors for a complete description of levels of evidence 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 Total knee replacement ( TKR ) is a common procedure for treatment of severe gonarthrosis  , but the outcome may be unsatisfactory due to primary malalignment of the prosthetic components . In order to improve precision and accuracy of this surgical procedure , a commercial robotic surgical system ( CASPAR ) has been adapted to assist the surgeon in the preoperative planning and intraoperative execution of TKR . So far , 70 patients with idiopathic gonarthrosis were successfully treated with a robot-assisted technique in our institution . No major adverse events related to the use of the robotic system have been observed . The mean difference between preoperatively planned and postoperatively achieved tibiofemoral alignment was 0.8 degrees ( 0 - 4.1 degrees ) in the robotic group vs. 2.6 degrees ( 0 - 7 degrees ) in a manually operated historical control group of 50 patients . A clear advantage of robot-assisted TKR seems to be the ability to execute a highly precise preoperative plan based on computed tomography ( CT ) scans . Due to better alignment of the prosthetic components and improved bone-implant fit , implant loosening is anticipated to be diminished which may be most evident in non-cemented prostheses . Current disadvantages such as the need for placement of fiducial markers , increased operating times and higher overall costs have to be resolved in the future 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 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
target: A literature review of robotic systems showed that these systems can , similarly to computer navigation , reliably improve lower leg alignment , component positioning and soft tissues balancing .
  Findings in this study suggest that computer navigation or robotic assistance may help managing these multiple variables and could improve outcomes .
background: Recently , there is a growing interest in surgical variables that are intraoperatively controlled by orthopaedic surgeons , including lower leg alignment , component positioning and soft tissues balancing .
  Since more tight control over these factors is associated with improved outcomes of unicompartmental knee arthroplasty and total knee arthroplasty ( TKA ) , several computer navigation and robotic-assisted systems have been developed .
  Although mechanical axis accuracy and component positioning have been shown to improve with computer navigation , no superiority in functional outcomes has yet been shown .
  This could be explained by the fact that many differences exist between the number and type of surgical variables these systems control .
  Most systems control lower leg alignment and component positioning , while some in addition control soft tissue balancing .
  Finally , robotic-assisted systems have the additional advantage of improving surgical precision .
  Manually controlling all these surgical variables can be difficult for the orthopaedic surgeon .