Comparative study between computer assisted-navigation and conventional technique in minimally invasive surgery total knee arthroplasty, prospective control study. Minimally invasive total knee arthroplasty: surgical implications for recovery. Computer-assisted total knee arthroplasty using mini midvastus or medial parapatellar approach technique Mini-subvastus versus medial parapatellar approach for total knee arthroplasty: a prospective randomized controlled study Simultaneous Bilateral MIS-TKA Results in Faster Functional Recovery Midterm outcomes of electromagnetic computer-assisted navigation in minimally invasive total knee arthroplasty Minimal invasive and computer-assisted total knee replacement compared with the minimal invasive technique: a prospective, randomized trial with short-term outcomes Minimally invasive total knee arthroplasty improves early knee strength but not functional performance: a randomized controlled trial. Does Minimally Invasive Total Knee Arthroplasty Improve Isokinetic Torque? The John Insall Award: No Benefit of Minimally Invasive TKA on Gait and Strength Outcomes: A Randomized Controlled Trial Five-year follow-up of minimally invasive computer assisted total knee arthroplasty (MICATKA) versus conventional computer assisted total knee arthroplasty (CATKA) - A population matched study. The effectiveness of minimally invasive total knee arthroplasty to preserve quadriceps strength: a randomized controlled trial. Patellar Tracking and Anterior Knee Pain are Similar After Medial Parapatellar and Midvastus Approaches in Minimally Invasive TKA Faster recovery after minimally invasive surgery in total knee arthroplasty Minimally invasive surgery (MIS) for total knee replacement; medium term results with minimum five year follow-up. Better quadriceps recovery after minimally invasive total knee arthroplasty Comparison of Early Postoperative Rehabilitation Outcome following Total Knee Arthroplasty Using Different Surgical Approaches and Instrumentation Clinical and radiologic outcomes of contemporary 3 techniques of TKA. Comparison of gait in patients following a computer-navigated minimally invasive anterior approach and a conventional posterolateral approach for total hip arthroplasty: a randomized controlled trial. Comparison of two minimally invasive implantation instrument-sets for total knee arthroplasty Minimally Invasive versus Classic Procedures in Total Hip Arthroplasty: A Double-blind Randomized Controlled Trial Comparison of quadriceps-sparing minimally invasive and medial parapatellar total knee arthroplasty: a 2-year follow-up study. Tackling the learning curve: comparison between the anterior, minimally invasive (Micro-hip®) and the lateral, transgluteal (Bauer) approach for primary total hip replacement
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 BACKGROUND Despite growing interest in minimally invasive surgery ( MIS ) techniques for total knee arthroplasty ( TKA ) , few r and omized controlled trials have compared MIS and conventional TKA using a combination of functional performance , knee pain , knee range of motion ( ROM ) , and surgical and radiographic outcomes . METHODS A prospect i ve , r and omized investigation comparing early outcomes of TKA using conventional or MIS approaches  ( n = 44 ) . Patients were assessed preoperatively , 48 hours , 4 and 12 weeks postoperatively by blinded evaluators . Outcome measures included timed-up- and -go , 100-ft walk , knee pain , passive knee ROM , Knee Society Score , blood loss , tourniquet time , hospital length of stay , surgical complications , and radiographic outcomes . RESULTS No significant differences in functional performance , knee pain , knee ROM , surgical , or radiographic outcomes were observed between groups at 48 hours , 4 or 12 weeks postoperatively . CONCLUSION While surgical and radiographic outcomes were not compromised with MIS surgery , there were also no improvements in pain , ROM , or functional performance with MIS TKA 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 Purpose Whether minimally invasive total knee arthroplasty ( MIS-TKA ) could offer better and faster recovery without the deviation of post-operative prosthesis position and limb alignment is still controversial . This prospect i ve and r and omized study was conducted to compare the clinical and radiological outcomes between patients who underwent the mini-subvastus approach of MIS-TKA and those who underwent the medial parapatellar approach of traditional TKA .  Methods Fifty patients , including 50 knees , who required TKA due to osteoarthritis were r and omized to the mini-subvastus group ( group I ) or the medial parapatellar group ( group II ) . All patients accepted the same method of anaesthesia , equal support therapy and identical rehabilitation exercise after surgery . The evaluation system included operation time , tourniquet time , blood loss , skin incision length in flexion , straight leg raising time , the time of lower limb muscle strength up to grade 4 , the time of walking with aid or without aid , the time of walking up and down the stairs , the active flexion angle , range of movement ( ROM ) , the Knee Society Scores ( KSS ) , visual analogue score for pain ( VAS ) , hospital stays and radiographic outcomes . Results The mini-subvastus approach offered smaller skin incision length in flexion , but at the cost of operation time ( P < 0.001 ) . No significant difference was found in tourniquet time and blood loss . The patients in group I could achieve straight leg raising , the lower limb muscle strength up to grade 4 , walking with or without aid , and walking up and down the stairs earlier ( P < 0.001 ) . The active flexion angle , ROM , VAS and KSS in group I were superior to those in group II until six months post-operatively ( P < 0.001 ) , but the differences was not apparent at 12 months post-operatively . More importantly , there was no significant difference between the two groups on radiological outcomes ( P > 0.05 ) . Conclusions The mini-subvastus approach could offer faster recovery , less pain and shorter hospital stays without compromising the principles of proper prosthesis position and limb alignment compared with the medial parapatellar approach Abstract Simultaneous bilateral TKAs subject patients to more arduous and painful functional recovery and increased risk of hemodynamic complications than staged bilateral TKAs . Minimally invasive TKA ( MIS-TKA ) reportedly results in more rapid return of function by limiting the amount of soft tissue disruption . We asked whether bilateral MIS-TKA had advantages over conventional TKA with respect to faster functional recovery . We prospect ively r and omized 30 patients into an MIS group ( mini-medial parapatellar approach , 15 patients ) and a conventional group ( conventional medial parapatellar approach , 15 patients ) . We recorded range of motion and the time required to regain the ability to walk without assistance . Functional recovery in the MIS group was faster in rehabilitation milestones of walking without assistance and gain in range of motion .  Minimally invasive TKA may benefit patients undergoing simultaneous bilateral procedures with faster functional recovery . Level of Evidence : Level II , therapeutic study . See the Guidelines for Authors for a complete description of levels of evidence 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 Abstract Introduction Up to now , no prospect i ve , r and omized comparisons between minimal invasive and computer-assisted total knee arthroplasty ( MICA-TKA ) , and minimal invasive technique ( MI-TKA ) has been documented to evaluate not only clinical , but also radiologic results of the MICA-TKA . This prospect i ve , r and omized study was performed to compare the short-term results of MICA-TKA with minimal invasive technique MI-TKA for 6-month follow-up . Patients and methods We reported the clinical and radiological results of 80 subjects who had cruciate-substituting , TKA-implanted primary total knee arthroplasties using either minimal invasive and computer-assisted technique ( 40 patients Group I ) or minimal invasive technique ( 40 patients , Group II ) .  Tourniquet time , length of skin incision , and total blood loss were compared . Knee society scores ( KSSs ) , knee society functional scores ( KSFSs ) , range of motion ( ROM ) , and radiographic results were assessed and reported preoperatively and at 6-month follow-up . Results The accuracy of the implantations in relation to the coronal mechanical axis in Group I was superior to that of Group II ( P < 0.05 ) . The femoral rotational profile revealed the prosthesis in Group I that was implanted with significantly less internal rotation than in Group II . The average blood loss in patients of Group I was significantly reduced as compared to patients of Group II . No significant difference was detected in terms of tourniquet time or length of skin incision . Clinical results , with regard to ROMs and KSSs , as well as KSFSs were equally good in both the groups . Conclusions Better alignment and similarity of good clinical results at short-term follow-up may provide subjects who receive MICA-TKA with long-term endurance of their implants . Further studies on longer-term outcomes and functional improvements are required to vali date these possibilities A prospect i ve , r and omized investigation compared early clinical outcomes of  total knee arthroplasty ( TKA ) using  conventional or minimally invasive surgical ( MIS ) approaches ( n = 44 ) . Outcome measures included isometric quadriceps and hamstrings strength , quadriceps activation , functional performance , knee pain , active knee range of motion , muscle mass , the Short Form-36 , and Western Ontario and McMaster University Osteoarthritis Index , assessed preoperatively and 4 and 12 weeks after TKA . Four weeks after TKA , the MIS group had greater hamstring strength ( P = .02 ) and quadriceps strength ( P = .07 ) , which did not translate to differences in other outcomes . At 12 weeks , there were no clinical ly meaningful differences between groups on any measure . Although MIS may lead to faster recovery of strength in patients undergoing TKA , there was no benefit on longer-term recovery of strength or functional performance Background Less invasive dissection of the extensor apparatus , one of the aspects of minimally invasive surgical ( MIS ) TKA , might result in less reduction of postoperative quadriceps strength . However , it is unclear whether MIS is associated with less strength reduction . Questions / purpose sWe asked whether knee strength ( extensor or flexor torque ) would be greater in patients having a MIS TKA  compared with patients having a st and ard TKA  and whether knee scores , alignment , ROM , tourniquet and operating times , and hospital length of stay were improved . Methods We prospect ively recruited 52 patients awaiting MIS or st and ard TKA , matched for age , weight , height , BMI , sex , and surgically treated side , but not r and omized .  Isokinetic tests  were performed preoperatively and postoperatively to obtain peak values of extensor and flexor torque . Postoperative-to-preoperative ratios and the extensor-flexor torque ratio also were calculated . Results Mean baseline extensor torques were 57 Nm and 53 Nm for MIS and st and ard TKAs , respectively . At 8 weeks postoperatively , absolute values of the mean postoperative knee extensor torque also were similar : 47 and 45 Nm for patients with MIS and st and ard TKAs , respectively . The postoperative-to-preoperative ratios were 0.8 for extensor and flexor torque in both groups . The extensor-flexor torque ratios were similar between groups . Conclusions Our data suggest a less invasive dissection of the extensor apparatus involved in MIS TKA does not enhance postoperative quadriceps strength . Level of Evidence Level III , therapeutic study . See Guidelines for Authors for a complete description of levels of evidence Background While some clinical reports suggest minimally invasive surgical ( MIS ) techniques improve recovery and reduce pain in the first months after TKA , it is unclear whether it improves gait and thigh muscle strength . Questions / Purpose sWe hypothesized TKA performed through a mini-subvastus approach would improve subjective and objective and subjective function compared to a st and ard medial parapatellar approach 2 months after surgery . Methods We r and omized 40 patients into two groups using either the mini-subvastus approach or st and ard medial parapatellar approach .  Patients were evaluated preoperatively and 2 months after surgery . We assessed subjective functional outcome and quality of life ( QOL ) using routine question naires ( SF-12 , Knee Society Score [ KSS ] , Knee Injury and Osteoarthritis Outcome Score [ KOOS ] , UCLA activity , patient milestone diary of activities ) . We determined isometric strength of the thigh muscles and assessed gait with a three-dimensional ( 3-D ) analysis during level walking and stair climbing . Results We observed improvements from preoperatively to 2 months postoperatively in functional scores , QOL , and knee kinematic and kinetic gait parameters during level and stair walking . Isometric quadriceps strength increased in both groups , although remaining lower when compared to sound limbs . We found no differences between the groups in KSS , SF-12 , KOOS , UCLA activity , patient milestone diary of activities , isometric quadriceps strength , or 3-D gait parameters , except a marginally higher speed of stair ascent in the MIS group . Conclusions Our observations suggest an MIS approach does not confer a substantial advantage in early function after TKA.Level of Evidence Level I , therapeutic study . See Instructions to Authors for a complete description of levels of evidence BACKGROUND Minimally invasive surgery ( MIS ) has perceived advantages in the early post-operative stage such as reduced blood loss , decreased pain , earlier return to function and earlier discharge . The aim of our study was to confirm that longer term clinical outcome of TKA is not compromised when MIS is combined with computer assisted surgery . METHODS Eighty patients matched for age , gender , pre-operative Knee Society Score ( KSS ) and mechanical axis were prospect ively studied . Forty patients underwent minimally invasive computer assisted total knee arthroplasty ( MICATKA ) and 40 patients underwent conventional computer assisted TKA ( CATKA ) .  Functional scores were determined at 6 weeks , 6 , 12 , 18 , and 24 months and 5 years post-surgery . Long-leg alignment views were obtained 3 months post-operatively . RESULTS KSSs in the short term were significantly better in the MICATKA group than in the CATKA group ( p<000.1 ) . Tourniquet-time was 58 min in the MICTKA group and 60 min in the CATKA group ( p=0.3 ) . Straight leg raise was achieved by day one in 93 % of the MICATKA group compared to 30 % of the CATKA group ( p<0.001 ) . Length of stay for the MICATKA group has a mean of 3.25 days and a mean of 6 days for the CATKA group ( p<0.001 ) . KSSs up to 2-years were significantly better in the MICTKA group ( p<0.001 ) . At 5-years there was no significant difference in KSSs ( p=0.46 ) in the MICATKA and CATKA groups . CONCLUSION We confirm that the use of navigation in minimally invasive TKA permits a number of early post-operative advantages and that longer-term functional outcome is not compromised with its usage . LEVEL OF EVIDENCE Level II We performed a single-center , r and omized , double-blind study to compare muscle strength in patients who had undergone primary total knee arthroplasty ( TKA ) , performed using either a minimally invasive or a conventional surgical technique . We evaluated 30 knees in healthy age-matched subjects , 22 knees after conventional TKA ( conventional group ) , and 23 knees after minimally invasive surgery TKA ( MIS group ) .  The Hospital for Special Surgery ( HSS ) score , Oxford knee score ( OKS ) , and isokinetic ( 60º/s ) muscle strength were evaluated the day before surgery and 3 , 6 , and 12 months after surgery . HSS and OKS improved significantly over time during follow-up ( p<0.001 ) , but there was no significant difference between the groups ( p>0.05 ) . The extensor peak torque ( EPT ) and flexor peak torque ( FPT ) improved significantly over time ( p<0.001 ) and EPT was greater in the MIS group than in the conventional group during the follow-up period ( p<0.05 ) . There was no difference in FPT and the hamstring-to-quadriceps ratio between the groups . Although MIS patients had a significant deficit in extensor strength following TKA , compared with healthy controls , this approach offers a significant improvement in extensor muscle strength over conventional surgery . These results suggest that the MIS approach results in better outcomes with regard to maintaining extensor strength than the conventional surgical approach Background Since the medial parapatellar ( MPP ) approach in conventional TKA can cause patellar maltracking and anterior knee pain , some orthopaedic surgeons use the midvastus ( MV ) approach instead of the MPP approach to reduce patellar maltracking . Minimally invasive surgical ( MIS ) TKA has been developed to limit the damage to the surrounding muscle and reduce the necessity of patellar eversion during surgery . Thus , MIS TKA might be associated with proper patellar tracking and a low incidence of anterior knee pain . However , this presumption has not been confirmed . Questions / purpose sWe asked whether the incidence of patellar maltracking and anterior knee pain differed with the MV and MPP in association with MIS TKA . Methods We prospect ively followed 59 patients ( 60 knees ) treated with 60 primary cemented MIS TKAs from August 2009 to September 2010 . We r and omized the patients into two groups : 30 who had a limited MPP approach and 30 who had a mini-MV approach . We recorded the occurrence of anterior knee pain , patellar tilting , and subluxation . The minimum followup was 12 months ( mean , 18.03 months ; range , 12.00–25.08 months ) . Results We found no differences in anterior knee pain ( two of 30 , 7 % versus two of 30 , 7 % ) , mean patellar tilt ( 3.4º ± 2.9º versus 3.0 ± 2.3º ) , and mean patellar subluxation ( 1.5 ± 1.1 mm versus 1.1 ± 0.7 mm ) between the limited MPP and mini-MV groups , respectively . Conclusions MIS TKA using either the MPP or MV approach has a low incidence of patellar maltracking and anterior knee pain . Level of Evidence Level I , therapeutic study . See the Guidelines for Authors for a complete description of the levels of evidence Purpose The aim of the study was to identify whether less soft tissue and muscle damage during surgery will allow faster recovery after total knee arthroplasty in comparison with the conventional technique . A limited medial parapatellar approach without tibial medial collateral ligament ( MCL ) desinsertion was compared with the conventional parapatellar approach . Methods Three hundred patients were r and omized either into the minimally invasive group ( MIS group ) or into the conventional group ( CON group ) . The evaluation was based on the Knee Society Score , range of motion , blood loss , period of hospitalization and postoperative hemoglobin level . Results The MIS group showed faster recovery with immediate postoperative full weight-bearing and shorter length of stay ( 5 vs 10 days ) . Comparable Knee Society Scores ( 87.5 vs 88 ) , function scores ( 90 ) and alignment ( 5.5 ° vs 5.2 ° ) between the CON and MIS group were observed at a follow-up of 24 months . No increase in operative times ( 52 vs 51 min tourniquet time ) or no complications were observed . Reduced blood loss was observed in the MIS group ( 590 vs 989 ml ) . Conclusion The MCL sparing limited medial parapatellar approach allows good surgical exposure , easy extension proximally if necessary , contained closure after surgery with less bleeding , faster recovery , full weight-bearing without aid and most importantly no radiological malalignment . Level of evidence Therapeutic study , Level II BACKGROUND MIS TKA has been shown to offer a reduced in-patient stay , but no clinical difference at two years . Whilst there may be a benefit from earlier discharge , we need to ensure that there are no detrimental effects in the medium and long-term following MIS-TKA . To report the mid-term result from a prospect i ve r and omised controlled trial ( RCT ) comparing MIS-TKA with st and ard approach for TKA . METHODS Using knee score question naires , we collected patient reported outcome measures ( PROMs ) regarding pain and function .  Sixty-six patients ( from an eligible cohort of 83 patients ) completed the mid-term postal follow-up . RESULTS There was no significant difference between groups for change in score from pre-operative to final follow-up in all three PROMs . Mean MIS and st and ard group improvement was : AKSS 53 and 51 ( p=0.7644 ) , OKS 15 and 16 ( p=0.2341 ) or WOMAC 15 and 15 ( p=0.9900 ) respectively . Both groups showed improvement in pain and function with no significant difference between groups . There was no difference between groups for revision due to malalignment at a mean six year follow-up . CONCLUSIONS In addition to the early benefits regarding hospital stay and complications , we have found that at a mean of six years there was no increase in malalignment , pain or function with MIS techniques Purpose The proponents of  minimally invasive total knee arthroplasty ( TKA )  have reported better functional recovery than conventional TKA . In most of the previous studies , the results were shown with the relatively subjective methods . We investigated the objective results with a dynamometry in this prospect i ve r and omized study . It was hypothesized that minimally invasive TKA would have a better and earlier recovery of quadriceps force in terms of the objective numeric data . Methods Sixty-six TKAs were prospect ively r and omized into two groups . Thirty-three knees underwent minimally invasive TKA using mini-midvastus approach and 33 knees underwent conventional TKA using medial parapatellar approach .  The quadriceps force was assessed using a dynamometer . The data were collected preoperatively and at postoperative 6 weeks , 3 months , 6 months and 1 year consecutively . Results The mean of quadriceps force in minimally invasive TKA group at postoperative 6 weeks was greater than conventional TKA after removing the covariate ( preoperative quadriceps force ) with analysis of covariance ( P = 0.002 ) , but thereafter , the difference was not significant till 1 year . Meanwhile , with repeated measures analysis of variance , conventional TKA group had greater quadriceps recovery than minimally invasive TKA group during postoperative 6 weeks to 3 months ( P = 0.035 ) . The proportion of patients unable to recover the quadriceps force to their preoperative levels by 1 year postoperatively was similar in two groups . Conclusion Minimally invasive TKA has benefit in quadriceps recovery at earlier rehabilitation period although catch-up recovery in conventional TKA was accelerated from the postoperative 6 weeks to 3 months . It may support the concept of early return to full activity after minimally invasive TKA , and patients might get back early to normal life . Level of evidence Therapeutic study , Level Purpose . To assess early postoperative rehabilitation outcome following  computer-assisted total knee arthroplasty ( TKA )  or st and ard instrumentation TKA using a medial parapatellar or subvastus approach . Methods . A prospect i ve controlled trial of 70 consecutive patients undergoing TKA with a low contact stress rotating platform prosthesis was conducted . Patients were r and omised to receive surgery with either computer navigation or st and ard instrumentation .  A medial parapatellar or subvastus approach was used according to the surgeons ' preference . Outcome measures included preoperative knee function , intra-operative factors , and postoperative rehabilitation . Results . Duration of surgery was significantly longer when using computer navigation ; however , operating time decreased with greater experience . A higher incidence and duration of early postoperative quadriceps dysfunction was associated with computer-assisted TKA through the medial parapatellar approach than through the subvastus approach or TKA performed with st and ard instrumentation . No patient who received surgery through the subvastus approach had a lag of more than 20 degrees , at 48 hours postoperatively , regardless of the instrumentation used . Conclusion . Computer-assisted TKA through a medial parapatellar approach was associated with delayed recovery of the quadriceps during early postoperative rehabilitation . This was due to the additional quadriceps dissection required to place the femoral tracking array . The subvastus approach is therefore recommended for computer-assisted TKA 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 Minimally invasive total hip arthroplasty ( MIS THA ) aims at minimizing damage to muscles and tendons to accelerate postoperative recovery . Computer navigation allows a precise prosthesis alignment without complete visualization of the bony l and marks during MIS THA . A r and omized controlled trial ( RCT ) was conducted to determine the effectiveness of a computer-navigated MIS anterior approach for THA compared to a conventional posterolateral THA technique on the restoration of physical functioning during recovery following surgery . Thirty-five patients underwent computer-navigated MIS THA via the anterior approach , and 40 patients underwent conventional THA using the conventional posterolateral approach .  Gait analysis was performed preoperatively , 6 weeks , and 3 and 6 months postoperatively using a body-fixed-sensor based gait analysis system . Walking speed , step length , cadence , and frontal plane angular movements of the pelvis and thorax were assessed . The same data were obtained from 30 healthy subjects . No differences were found in the recovery of spatiotemporal parameters or in angular movements of the pelvis and thorax following the computer-navigated MIS anterior approach or the conventional posterolateral approach . Although gait improved after surgery , small differences in several spatiotemporal parameters and angular movements of the trunk remained at 6 months postoperatively between both patient groups and healthy subjects Several choices of instrument systems are available for minimally invasive surgical approaches . There are reports that one alternative , the quadriceps sparing , side-cutting instrumentation , results in diminished implantation accuracy . A total of 108 patients were r and omized to undergo TKA either using side-cutting implant instrumentation ( Group A ) or anterior – posterior mini-incision instrumentation ( Group B ) . All TKAs were operated on with a minimal invasive , mini-midvastus surgical approach . 50 % of the TKAs were performed with computer-assistance in each cohort . The radiographic parameters , clinical outcomes and knee scores were evaluated preoperatively and 3 months postoperative . In Group B , we found significantly higher accuracy for the mechanical axis of the limb ( range ±3 ° : Group A 54 % versus Group B 89 % , p = < 0.001 ) , medial proximal tibial angle ( range ±3 ° : Group A 85 % versus Group B 98 % , p = < 0.027 ) and tibial slope ( range ±3 ° : Group A 59 % versus Group B 85 % , p = < 0.007 ) . The application of the navigation system could only significantly reduce outliers ( accuracy > 3 ° ) in Group B. Clinical outcomes and knee scores were similar in both groups and were not influenced by computer-assistance . Using the anterior – posterior , mini-incision instruments for minimally invasive TKA will lead to higher implantation accuracy when compared to the quadriceps sparing side-cutting instrumentation . The navigation technique could not compensate for shortcomings of the side-cutting instrumentation . The clinical relevance of this study is that the quadriceps sparing side-cutting instrumentation should not be used for TKA because of unacceptable reduced implantation accuracy Background For total hip arthroplasty ( THA ) , minimally invasive surgery ( MIS ) uses a smaller incision and less muscle dissection than the classic approach ( CLASS ) , and may lead to faster rehabilitation . Questions / purpose sDoes minimally invasive hip arthroplasty result in superior clinical outcomes ? Patients and Methods In this double-blind r and omized controlled trial , 120 consecutive primary noncemented THAs in 120 patients were assigned to one of two groups ( MIS or CLASS ) . The r and omization sequence was stratified for two groups of surgeons , ie , those using a posterolateral approach ( PL-CLASS or PL-MIS ) and those using an anterolateral approach ( AL-CLASS or AL-MIS ) . Length of the incisions was 18 cm for the CLASS procedures . MIS incisions were extended at the skin level to 18 cm at the end of the procedure . The primary end point was the Harris hip score ( HHS ) at 6 weeks postoperatively . Patient-centered question naires were obtained preoperatively and after 6 weeks and 1 year . Results For the patients in the MIS group ( average 7.8 cm incision length ) , statistically significant increased mean HHSs were seen compared with the CLASS group at 6 weeks and 1 year . This difference was small and mainly caused by the favorable results of the PL-MIS . In the MIS group , surgical time was longer . A learning curve was observed based on operation time and complication rate . Although not statistically significant , the perioperative complication rate was rather high in the ( anterolateral ) MIS group . Conclusions The minimal invasive approach in THA did not show a clinical ly relevant superior outcome in the first postoperative year . Level of Evidence Level I , therapeutic study . See Guidelines for Authors for a complete description of levels of evidence BACKGROUND / PURPOSE Quadriceps-sparing minimally invasive total knee arthroplasty ( TKA ) has been proposed to limit surgical dissection without compromising surgical outcome . We conducted a prospect i ve and r and omized study to compare the outcomes of patients who underwent quadriceps-sparing TKA  with the outcomes of those who underwent st and ard medial parapatellar TKA  , after a 2-year follow-up period . METHODS Eighty primary TKA procedures that were to be performed in 60 osteoarthritis patients were r and omly assigned to either a  quadriceps-sparing ( 40 knees ) or a  st and ard medial parapatellar ( 40 knees ) group . All surgeries were design ed to set the prosthesis with a femoral component alignment of 7 ° valgus and a tibial component alignment that was perpendicular to the tibial shaft . Surgical time and  tourniquet time were recorded . Outcome variables included knee function , as defined by a hospital for special surgery knee score ; quadriceps muscle strength , which was measured by an isokinetic dynamometer ; pain , as indicated on a visual analog scale ; prosthetic position , which was measured on plain radiograph ; and range of motion . RESULTS Patients who underwent the 38 quadriceps-sparing and 37 st and ard TKA  procedures completed the 2-year follow-up period without any infection or revision . The mean surgical time and tourniquet time were significantly longer in the quadriceps-sparing group . The mean peak quadriceps muscle strength , hamstring muscle strength , normalized muscle balance ( hamstring/quadriceps ratio ) , pain score , function score , and range of motion were comparable in both groups at 2 months and 2 years . In the quadriceps-sparing group , both the femoral and the tibial components were significantly more varus-deviated from the expected position . CONCLUSIONS Patients undergoing quadriceps-sparing and st and ard medial parapatellar TKA  had comparable outcomes for quadriceps muscle strength , hamstring-quadriceps balance , and knee function ; however , the quadriceps-sparing TKA was more time consuming surgically and result ed in a less accurate prosthesis position Background and purpose There is still conflicting evidence about the true benefit of minimally invasive ( MI ) techniques in total hip replacement ( THR ) . The aim of this prospect i ve study was to evaluate the safeness of a MI approach during the learning curve of a single surgeon . Second , clinical and radiographic results among the  MI THR group were compared with the results using a st and ard transgluteal ( Bauer ) approach . Methods 86 primary unilateral total hip arthroplasties ( THAs ) through a MI , anterior ( Micro-hip ® ) approach were performed by a single senior surgeon ( ES ) , representing a consecutive series of patients after beginning with the MI technique . Cases were compared to a matched cohort of patients who were treated with a st and ard transgluteal ( Bauer ) approach .  Operation time , incision length , perioperative blood loss , haemoglobin level and blood transfusions were monitored . Complications were documented and followed up 1 year postoperatively . The Harris Hip Score ( HHS ) , range of motion , use of analgetics , the Trendelenburg sign , sensibility of the lateral femoral cutaneous nerve and the acetabular/femoral component placement as well as potential heterotopic ossifications were analysed in both the groups after 12 months postoperatively . Results 74 MI THR patients and 60 st and ard THR patients were available for the one year follow-up . Operative time was significantly longer in the MI group , reduction in the haemoglobin level during the first 24 h was significant and the length of skin incision was significantly shorter . No significant differences were found for HHS , range of motion , use of analgetics , the Trendelenburg sign , and the acetabular/femoral component placement , heterotopic ossifications and intra- and postoperative complications . Sensibility of the lateral femoral cutaneous nerve was affected in three patients in the MI group . Radiographic evaluation revealed no component migration , implant subsidence or radiolucency signs in both the groups . DicussionConsistent with recent meta- analysis we found reduced blood loss , similar clinical /radiographic outcome and similar complication rates compared to st and ard THA . Our study shows , that MI THR is a safe procedure during the learning curve of an experienced surgeon
There was no significant difference in the outliers on complications , knee flexion , and postoperative functional scores .
Coronal plane tibial component showed statistically significant number of outliers in the MIS group demonstrating superior component positioning in the MIS CA group .
Computer-assisted minimally invasive TKA is superior than the st and ard MIS TKA in terms of component positioning ; however , it is unclear if this will have any long-term clinical implication s. The increased operative time , although clinical ly relevant , does not appear to be associated with an increase in complications
BACKGROUND Median parapatellar approach is the most used for total knee arthroplasty ( TKA ) .
With the advent of enhanced recovery and shorter length of hospital stay , there is an increasing pressure on surgeons to perform surgery through smaller incisions .
Minimally invasive ( MIS ) TKA allows earlier functional recovery ; it is not clear if this is associated with more complications .
It is also unclear if computer-assisted minimally invasive ( MIS CA ) TKA has any affect on improving patient outcomes .
We performed a systematic review and meta- analysis comparing MIS CA vs MIS TKA .