Comparative study between computer assisted-navigation and conventional technique in minimally invasive surgery total knee arthroplasty, prospective control study. Alignment in total knee arthroplasty. A comparison of computer-assisted surgery with the conventional technique. Early experiences with robot-assisted total knee arthroplasty using the DigiMatch™ ROBODOC® surgical system. Robot-assisted Total Knee Arthroplasty Reliability of computer-assisted surgery as an intraoperative ruler in navigated high tibial osteotomy Robot-assisted total knee arthroplasty accurately restores the joint line and mechanical axis. A prospective randomised study. Patient-specific computed tomography based instrumentation in total knee arthroplasty: a prospective randomized controlled study Computer-assisted total knee arthroplasty using mini midvastus or medial parapatellar approach technique Robotic-assisted TKA Reduces Postoperative Alignment Outliers and Improves Gap Balance Compared to Conventional TKA Navigated intraoperative analysis of lower limb alignment Computer-assisted techniques versus conventional guides for component alignment in total knee arthroplasty: a randomized controlled trial. Comparison between patient-specific instruments and conventional instruments and computer navigation in total knee arthroplasty: a randomized controlled trial Mini-incision versus mini-incision and computer-assisted surgery in total knee replacement: a radiological prospective randomised study. Leg axis after computer-navigated total knee arthroplasty: a prospective randomized trial comparing computer-navigated and manual implantation. Randomized trial of computer-assisted knee arthroplasty: impact on clinical and radiographic outcomes. Technique and first clinical results of robot-assisted total knee replacement. Comparison between computer-assisted-navigation and conventional total knee arthroplasties in patients undergoing simultaneous bilateral procedures: a randomized clinical trial.
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 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 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 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 Background Computer-assisted surgery ( CAS ) can act as an intraoperative ruler in high tibial osteotomy ( HTO ) to visualize continuously the leg during surgery . Questions The aim of the study is to evaluate the accuracy of  CAS with respect to preoperative planning and postoperative deviation from the planned leg axis in HTO . In addition , the influence of surgeon experience as well as operation time and perioperative complications are analyzed . Methods A prospect i ve multicenter study case series with follow-up at 6 weeks was performed in six centers .  Medial open-wedge HTO with Tomofix ® was done using computer assisted navigation technique with the Brainlab VV Osteotomy 1.0 module . Results Fifty-one patients with medial gonarthritis were treated with navigated HTO . The follow-up rate was 98 % . The majority of HTO – CAS patients fell within the tolerated limit of ±3 ° for leg axis deviation , however , seven patients were reported with deviations outside of this range : three patients had deviations of > 3 ° –4.5 ° and four patients > 4.5 ° , respectively . Eight intraoperative complications were documented , partially result ing from technical problems associated with the navigation system . During the 6-week follow-up period , three postoperative complications were experienced , all not associated with navigation technology . Conclusions In about 85 % of cases , a perfect result in terms of deviation of the planned mechanical leg axis could be achieved . Computer assistance in HTO proved to be a helpful tool regarding intraoperative control of leg axis . Level of evidence Level I , High quality prospect i ve study ( all patients were enrolled at the same preoperative planning point with ≥80 % follow-up of enrolled patients ) 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 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 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 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 Introduction : Accurate intraoperative assessment of lower limb alignment is crucial for the treatment of long bone fractures , implantation of knee arthroplasties and correction of deformities . During orthopaedic surgery , exact real time control of the mechanical axis is strongly desirable . The aim of this study was to compare conventional intraoperative analysis of the mechanical axis by the cable method with continuous , 3-dimensional imaging with a navigation system . Material s and methods : Twenty legs of fresh human cadaver were r and omly assigned to conventional analysis with the cable method ( n=10 ) or navigated analysis with a fluoroscopy based navigation system ( n=10 ) . The intersection of the mechanical axis with the tibia plateau was presented as percentage of the tibia plateau ( beginning with 0 % at the medial border and ending with 100 % laterally ) . CT-scans were performed for all legs and the CT-values of the mechanical axis were compared to the measurements after cable method and navigation . Furthermore , the radiation time and dose area product of both groups for single analysis of the mechanical axis was compared . Results : Conventional evaluation of the mechanical axis by the cable method showed 6.0±3.1 % difference compared to the analysis by CT . In the navigated group the difference was 2.6±1.8 % ( P=0.008 ) . Radiation time and dose area product were highly significantly lower after conventional measurement . Conclusions : Navigated intraoperative evaluation of the mechanical axis offers increased accuracy compared to conventional intraoperative analysis . Furthermore , navigation provides continuous control not only of the mechanical axis , but also of the sagittal and transverse plane . Using the cable method , radiation exposure depends on the number of measurements and is lower compared to the navigation system for single intraoperative analysis of the mechanical axis , but may be higher in case of repeated intraoperative measurements BACKGROUND Optimal alignment of the prosthesis in total knee arthroplasty results in improved patient outcomes . The goal of this study was to determine the most accurate technique for component alignment in total knee arthroplasty by comparing computer-assisted surgery with two conventional techniques involving use of an intramedullary guide for the femur and either an intramedullary or an extramedullary guide for the tibia . METHODS One hundred and seven patients were r and omized prior to surgery to one of three arms :  computer-assisted surgery for both the femur and the tibia ( the computer-assisted surgery group ) , intramedullary guides for both the femur and the tibia ( the intramedullary guide group ) , and an intramedullary guide for the femur and an extramedullary guide for the tibia ( the extramedullary guide group ) . Measurements of alignment on hip-to-ankle radiographs and computed tomography ( CT ) scans made three months after surgery were evaluated . The operative times and complications were compared among the three groups . RESULTS The coronal tibiofemoral angle demonstrated , on average , less malalignment in the computer-assisted surgery group ( 1.91 ° ) than in the extramedullary ( 3.22 ° ) and intramedullary ( 2.59 ° ) groups ( p = 0.007 ) . The coronal tibiofemoral angle was > 3 ° of varus or valgus deviation in 19 % ( seven ) of the thirty-six patients treated with computer-assisted surgery compared with 38 % ( thirteen ) of the thirty-four in the extramedullary guide group and 36 % ( thirteen ) of the thirty-six in the intramedullary guide group ( p = 0.022 ) . The increase in accuracy with computer-assisted surgery came at a cost of increased operative time . The operative time for the computer-assisted surgery group averaged 107 minutes compared with eighty-three and eighty minutes , respectively , for the surgery with the extramedullary and intramedullary guides ( p < 0.0001 ) . There was no significant difference in any of the outcomes between the intramedullary and extramedullary guide groups . CONCLUSIONS This study provides evidence that the implant alignment with computer-assisted total knee arthroplasty , as measured with radiography and computed tomography , is significantly improved compared with that associated with conventional surgery with intramedullary or extramedullary guides . This finding adds to the body of evidence showing an improved radiographic outcome with computer-assisted surgery compared with that following conventional total knee arthroplasty 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 The aim of this trial was to compare the radiological results of 74 patients undergoing a mini-invasive total knee replacement ( TKR ) using either a traditional alignment guide ( MIS group ) or a computer assisted alignment system ( MICA group ) . All the patients were prospect ively r and omised to either group and the same implant was used for both groups . At 8 months post-operatively , the frontal femoral component angle ( FFC ) , the frontal tibial component angle ( FTC ) , the hip-knee-ankle angle ( HKA ) and the sagittal orientation of components ( slopes ) were evaluated respectively . The slopes of the femoral component and the FTC angle were statistically better aligned in the MICA group ( p<0.001 ) . The MICA group showed both a significant fewer number of outliners and a significant higher number of implants with all five radiological parameters ideally aligned . The operative time was statistically longer in the computer assisted group To compare the alignment after computer-navigated total knee arthroplasty , 52 patients were r and omly allocated to 2 groups . Twenty-seven patients received a total knee arthroplasty with the aid of a kinematic computer-navigation system , and 25 patients received a total knee arthroplasty with the conventional method . Both groups were well balanced concerning demographic data and preoperative scores . At 3-month follow-up , the mechanical alignment of the leg reached the desired straight axis in more cases with the computer-navigated implantation . This difference was statistically significant . The femoral and tibial mechanical anteroposterior axis and the femoral and tibial sagittal tilt ( slope ) measured on sagittal x-rays were not significantly improved in this patient group Computer-assisted surgery in knee arthroplasty is gaining popularity ; however , the result ing outcome improvement is controversial . A double-blinded trial was performed with subjects r and omized to undergo surgery with either computer-assisted or nonassisted instruments .  Postoperatively , limb and implant alignment and rotation were assessed using both full-length radiographs and computed tomography in addition to clinical scores . One hundred twenty patients ( 141 knees ) were r and omized . No differences in Western Ontario MacMaster Osteoarthritis Score , Short Form-36 , or flexion were seen . More varus limb alignment was seen in the computer-assisted group ( 1.9 ° ) vs the nonassisted group ( 0.9 ° , P = .04 ) with no improvement in alignment precision . Rotational alignment of the components did not differ between groups . Computer-assisted surgery appeared to have minimal effect on knee implant arthroplasty with no improvement in limb alignment or early functional outcome 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 BACKGROUND Total knee arthroplasty has been increasingly used for young and active patients , and prosthesis durability is important in these patients . The accuracy of implant placement has been one of the major factors that determine the long-term survival of the prosthesis . The purpose of this study was to compare the accuracy of prosthetic alignment between computer-assisted-navigation and conventional total knee arthroplasties . METHODS From March 2007 to June 2008 , thirty-two patients with bilateral knee osteoarthritis underwent simultaneous bilateral total knee arthroplasty with the same type of implant in each knee .  The subjects included seven men and twenty-five women , with an average age of sixty-three years . For each patient , the bilateral total knee arthroplasty was performed with computer-assisted navigation in one knee and a conventional technique in the other . The operative technique and the order of the surgical procedures were r and omized . The patients and surgeons conducting the follow-up study and performing the imaging measurements were blinded to the type of surgical procedure . RESULTS There was a significant difference between the two groups with regard to the alignment of the knee prosthesis in the coronal and sagittal planes . Nine knee implants ( 28 % ) in the conventional group , compared with no knee implants in the computer-navigation group , deviated > 3 ° from the mechanical axis in the coronal plane . The coefficient variation of data in the conventional group was three times greater than that in the computer-navigation group . There was no significant difference in the rotational angle of the femoral component between the two groups . The Hospital for Special Surgery ( HSS ) scores at six months postoperatively were substantially increased compared with the preoperative scores in both groups . CONCLUSIONS Computer-assisted navigation consistently provided coronal plane alignment within 3 ° of the mechanical axis , which was significantly better than the alignment obtained with conventional total knee arthroplasty
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 .
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 .