title: Component position following total hip arthroplasty through a miniinvasive posterolateral approach. Total hip arthroplasty through a minimally invasive lateral approach--our experience and early results. Greater accuracy in positioning of the acetabular cup by using an image-free navigation system Does a "Level I Evidence" rating imply high quality of reporting in orthopaedic randomised controlled trials? A minimal-incision technique in total hip arthroplasty does not improve early postoperative outcomes. A prospective, randomized, controlled trial. Computed tomography measurement of the accuracy of component version in total hip arthroplasty. The effect of total hip arthroplasty surgical approach on gait. Minimally invasive total hip arthroplasty: a randomized controlled prospective trial Responsiveness and clinically important differences for the WOMAC and SF-36 after hip joint replacement. Image Guided Navigation System to Measure Intraoperatively Acetabular Implant Alignment Comparison of the responsiveness of the Harris Hip Score with generic measures for hip function in osteoarthritis of the hip [Comparison of total hip arthroplasty via a posterior mini-incision versus a classic anterolateral approach]. Imageless navigation for insertion of the acetabular component in total hip arthroplasty: is it as accurate as CT-based navigation? Validation and usefulness of a computer-assisted cup-positioning system in total hip arthroplasty. A prospective, randomized, controlled study. Reduction in variability of acetabular cup abduction using computer assisted surgery: a prospective and randomized study. Comparison of gait kinematics in patients receiving minimally invasive and traditional hip replacement surgery: a prospective blinded study. Comparison of early postoperative functional levels following total hip replacement using minimally invasive versus standard incisions. A prospective randomized blinded trial Mini-incision technique for total hip arthroplasty with navigation. Comparison of primary total hip arthroplasties performed with a minimally invasive technique or a standard technique: a prospective and randomized study. Minimally invasive total hip arthroplasty: a prospective randomized study. Early pain relief and function after posterior minimally invasive and conventional total hip arthroplasty. A prospective, randomized, blinded study. Objective functional assessment of total hip arthroplasty following two common surgical approaches: The posterior and direct lateral approaches
abstract: Implant malposition and poor fixation are potential risks of compromising long-term results after total hip arthroplasty performed with a minimally invasive technique . Between September 2000 and February 2002 , 120 cemented primary total hip arthroplasties were performed at the authors ' institutions in patients with primary osteoarthritis of the hip and with BMI lower than 35 . In 60 of these cases selected at r and om , a posterolateral incision no longer than 10 cm was used . The other 60 THA 's were performed through a st and ard posterolateral approach . The inclination and anteversion of the cup and the position of the femoral stem were assessed on radiographs and statistically evaluated . In the miniinvasive group , the average inclination angle of the cup was 42.3 degrees ( range : 36 to 52 degrees ) and the anteversion angle 13.6 degrees ( range : 6 to 29 degrees ) . The coronal alignment of the femoral component was within 3 degrees of neutral in 54 cases ( 90.0 % ) . Following conventional implantation in the other group , the average cup inclination angle was 42.4 degrees ( range : 35 to 50 degrees ) and the anteversion angle 13.6 degrees ( range : 8 to 24 degrees . A total of 53 stems ( 88.3 % ) were implanted optimally . Statistical analysis found no significant difference between the two groups regarding components position . These findings suggest that using a smaller posterolateral incision as was done in this study does not introduce a potential risk of compromising long-term results BACKGROUND AIMS Evaluation of : 1 . early clinical and radiographic results of  total hip arthroplasty ( THA ) through a st and ard lateral direct approach , 2 . early clinical and radiographic results of THA through a minimal lateral approach , 3 . comparison of the results of THA in these two groups . MATERIAL AND METHODS 120 THAs ( 60 cementless and 60 cemented ) done in 120 patients due to degenerative changes were evaluated prospect ively . 60 THAs were done through a minimal lateral approach and constituted a study group . 60 THAs were done through a direct lateral approach and constituted a control group . The mean age of the 120 patients ( 98 women and 22 men ) was 45 y.o . ( range : 32 - 67 y.o . ) . The duration of follow-up in the study group was from 6 to 12 months ( mean : 8.5 months ) . The duration of follow-up in the control group was from 10 to 16 months ( mean : 10.5 months ) . Mean preoperative functional status of the study group was 44.5 points according to the Harris hip score . Radiographic evaluation of the results was done according to the criteria of the Joint Committee of the Hip Society , AAOS and SICOT . RESULTS 6 months after THA , clinical results were 92 pts in the study group and 88 pts in the control group . Radiographic outcomes were very good in all 120 patients from both arms : there were no differences between the control and study group . The incidence of complications was similar in both groups . CONCLUSIONS Minimally invasive THA demonstrated its value in the treatment of  degenerative changes of the hip joint  with regard to short-term outcomes . The clinical and radiographic outcomes were comparable between the st and ard and minimally invasive approaches . Success with THA using a minimally invasive approach depends on excellent operative technique and experience with st and ard hip approaches rather than on the use of special instruments In a prospect i ve and r and omised clinical study ,  acetabular cups were implanted free-h and  ( control group n=22 )  or with computer assistance using an image-free navigation system ( study group n=23 ) . The cup position was determined postoperatively on pelvic CT . An average inclination of 42.3 ° ( range : 30 ° –53 ° ; SD±7.0 ° ) and an average anteversion of 24.0 ° ( range : −3 ° to 51 ° ; SD±15.0 ° ) were found in the control group , and an average inclination of 45.0 ° ( ranage : 40 ° –50 ° ; SD±2.8 ° ) and an average anteversion of 14.4 ° ( range : 5 ° –25 ° ; SS±5.0 ° ) in the computer-assisted study group . The deviations from the desired cup position ( 45 ° inclination , 15 ° anteversion ) were significantly lower in the computer-assisted study group ( p<0.001 each ) . While only 11/22 of the cups in the control group were within the Lewinnek safe zone , 21/23 of the cups in the study group were placed in this target region (p=0.003).RésuméDans un étude clinique prospect i ve et r and omisé , les cupules acétabulaires ont été implantées de façon habituelle ( n=22 ; groupe témoin ) ou avec assistance d’un ordinateur qui utilise un système de navigation image — libre ( n=23 ; groupe d’étude ) . La place de la cupule a été déterminée après l’opération sur un scanner pelvien . Une inclinaison moyenne de 42,3 ° ( 30 ° à 53 ° ; ±7.0 ° ) et une antéversion moyenne de 24,0 ° ( −3 ° à 51 ° ; ±15.0 ° ) ont été trouvées dans le groupe témoin et une inclinaison moyenne de 45,0 ° ( 40 ° à 50 ° ; ±2.8 ° ) et une antéversion moyenne de 14,4 ° ( 5 ° à 25 ° ; ±5.0 ° ) dans le groupe de l’étude assistée par ordinateur . Les déviations par rapport à la position désirée de la cupule ( 45 ° d’inclinaison , 15 ° d’antéversion ) étaient notablement inférieures dans le groupe de l’étude assistée par ordinateur ( p<0.001 chacun ) . Alors que seulement 11 des 22 cupules du groupe témoin étaient dans la zone sûre de Lewinnek , 21 des 23 cupules du groupe d’étude ont été placées dans cette région cible ( p=0.003 ) Background The Levels of Evidence Rating System is widely believed to categorize studies by quality , with Level I studies representing the highest quality evidence . We aim ed to determine the reporting quality of R and  omised Controlled Trials ( RCTs ) published in the most frequently cited general orthopaedic journals . Methods Two assessors identified orthopaedic journals that reported a level of evidence rating in their abstract s from January 2003 to December 2004 by search ing the instructions for authors of the highest impact general orthopaedic journals . Based upon a priori eligibility criteria , two assessors h and search ed all issues of the eligible journal from 2003–2004 for RCTs . The assessors extracted the demographic information and the evidence rating from each included RCT and scored the quality of reporting using the reporting quality assessment tool , which was developed by the Cochrane Bone , Joint and Muscle Trauma Group . Scores were conducted in duplicate , and we reached a consensus for any disagreements . We examined the correlation between the level of evidence rating and the Cochrane reporting quality score . Results We found that only the Journal of Bone  and Joint  Surgery –  American Volume ( JBJS-A ) used a level of evidence rating from 2003 to 2004 . We identified 938 publications in the JBJS-A from January 2003 to December 2004 . Of these publications , 32 ( 3.4 % ) were RCTs that fit the inclusion criteria . The 32 RCTs included a total of 3543 patients , with sample sizes ranging from 17 to 514 patients . Despite being labelled as the highest level of evidence ( Level 1 and Level II evidence ) , these studies had low Cochrane reporting quality scores among individual method ological safeguards . The Cochrane reporting quality scores did not differ significantly between Level I and Level II studies . Correlations varied from 0.0 to 0.2 across the 12 items of the Cochrane reporting quality assessment tool ( p > 0.05 ) . Among items closely corresponding to the Levels of Evidence Rating System criteria assessors achieved substantial agreement ( ICC = 0.80 , 95%CI:0.60 to 0.90 ) . Conclusion Our findings suggest that readers should not assume that 1 ) studies labelled as Level I have high reporting quality and 2 ) Level I studies have better reporting quality than Level II studies . One should address method ological safeguards individually BACKGROUND Minimally invasive total hip arthroplasty has stirred substantial controversy with regard to whether it provides superior outcomes compared with total hip arthroplasty performed through longer incisions . The orthopaedic literature is deficient in well- design ed scientific studies to support the clinical superiority of this approach . The objective of this study was to compare the results of a single mini-incision approach with those of a st and ard-incision total hip arthroplasty in the early postoperative period . METHODS Two hundred and nineteen patients ( 219 hips ) admitted for unilateral total hip arthroplasty between December 2003 and June 2004 were r and omized to undergo surgery through a short incision of < or=10 cm or a st and ard incision of 16 cm .  All patients were blinded to the size of the incision for the duration of the hospital stay . The anesthetic , analgesic , and postoperative physiotherapy protocol s were st and ardized , with the staff also blinded to the technique used . A single surgeon , who had performed more than 300 short-incision hip replacements prior to the start of this study and who performs an average of 415 primary total hip replacements a year , performed all procedures through a single-incision posterior approach using a cementless cup and cemented stem . RESULTS The two groups were matched for age , grade according to the system of the American Society of Anesthesiologists , and body mass index . No significant difference was detected with respect to postoperative hematocrit , blood transfusion requirements , pain scores , or analgesic use . We found no difference in early walking ability or length of hospital stay and no difference in component placement , cement-mantle quality , or functional outcome scores at six weeks . The patient variables significantly associated with a probability of early discharge independent of incision length were patient age and preoperative hemoglobin levels ( p < 0.05 ) . The surgical scars contracted significantly over six weeks ( p < 0.05 ) but by a similar proportion of 11 % to 12 % in both groups . CONCLUSIONS Minimally invasive total hip arthroplasty performed through a single-incision posterior approach by a high-volume hip surgeon with extensive experience in less invasive approaches to the hip is safe and reproducible . However , it offers no significant benefit in the early postoperative period compared with a st and ard incision of 16 cm . As it is not known whether lower-volume and less-experienced surgeons can achieve similar results , the mini-incision technique merits further study before wide dissemination and implementation of this family of surgical approaches can be recommended The version of the acetabular and femoral components in 111 primary total hip arthroplasties was prospect ively evaluated intraoperatively by the surgeon and compared with postoperative computed tomography ( CT ) scan measurements . Intraoperative estimations by the surgeons for acetabular and femoral components were all within 10 degrees to 30 degrees anteversion , with means of 16.0 degrees ( SD = 4.0 degrees ) and 16.4 degrees ( SD = 3.2 degrees ) , respectively . However , CT scan acetabular measurements ranged from 12 degrees retroversion to 52 degrees anteversion ( mean = 22.0 degrees anteversion , SD = 14.0 degrees ) . Similarly , femoral component version ranged from -15 degrees retroversion to 45 degrees anteversion ( mean = 16.8 degrees anteversion , SD = 11.1 degrees ) . According to CT calculations , only 71 % of femoral and 45 % of acetabular components were within the expected clinical version range . In conclusion , the intraoperative estimation of acetabular and femoral version in a total hip arthroplasty is of limited accuracy This study examined the effect of the surgical approach used in  total hip arthroplasty ( THA )  on gait mechanics six months following surgery . Quantitative gait analysis was performed on 29 subjects : 10 anterolateral ( A-L ) and 10 posterolateral ( P-L ) THA patients and nine able-bodied , velocity-matched subjects . Discriminant function analysis was used to determine the distinction of the groups with respect to sagittal plane hip range of motion , index of symmetry , trunk inclination , pelvic drop , hip abduction , and foot progression angles . The A-L group had the largest trunk inclination ( 3.0+/-2.4 degrees ) and the smallest hip range of motion ( 34.0+/-7.4 degrees ) . Both THA groups demonstrated greater asymmetry as expressed by the smaller symmetry index ( 0.97+/-0.04 for A-L and 0.98+/-0.05 for the P-L ) than the able-bodied group ( 0.99+/-0.01 ) . The classification procedure correctly classified 89 % of the control group cases , 90 % of the A-L cases , and 50 % of the P-L cases . These results support the conclusion that six months following surgery , the gait of the majority ( 85 % ) of THA patients has not returned to normal . The A-L patients displayed distinct gait patterns , while a small percentage ( 30 % ) of the P-L patients demonstrated normal gait . While these differences are statistically significant , the clinical significance is unknown and linked to the duration that they persist Introduction Advantages of minimally invasive total hip arthroplasty ( THA )  are controversially discussed . Method In this prospect i ve study 51 patients ( 52 hips ) were r and omly allocated to a classical lateral or a minimally invasive approach ( modification of the Hardinge-approach ) . Operating time , intraoperative blood loss , postoperative hemoglobin , muscle enzymes CK and myoglobin were recorded . Radiologically the positioning of the prosthesis was analyzed . WOMAC- and Harris Hip Score ( HHS ) were assessed preoperatively , at discharge , at 6 weeks and 3 months . Results In the minimally invasive group there was a shorter length of surgery , the scores in the WOMAC and HHS were slightly better at discharge and at the 3 months- examination , myoglobin-rise was slightly less . The positioning of the prosthesis was good in both groups . Minimally invasive THA led to a quicker recovery , at 3 months postoperative there was still a slight difference to the st and ard group . Conclusion If these slight differences subside has to be examined in studies with a longer follow-up OBJECTIVES To study responsiveness and establish the minimal clinical ly important differences ( MCID ) and minimal detectable change ( MDC ) in patients undergoing total hip replacement ( THR )  using the Short Form 36 ( SF-36 ) and the Western Ontario and McMaster Universities Osteoarthritis Index ( WOMAC ) . METHODS We conducted a prospect i ve observational study in three public hospitals of all consecutive patients with a diagnosis of hip osteoarthritis ( OA ) on waiting lists to undergo THR .  Patients completed the SF-36 and the  WOMAC  ( subscales transformed to 0 to 100 ) , which measured the health-related quality of life ( HRQoL ) , before intervention and 6 months and 2 years later , and additional transitional questions , which measured the changes in the joint 6 months postoperatively . RESULTS Improvements at 6 months after a THR were between 37 ( stiffness ) and 39 points ( pain ) , depending on the WOMAC domain . The SF-36 domains also showed improvements : physical function ( 31.91 ) , physical role ( 33.71 ) , and bodily pain ( 29.77 ) . From 6 months to 2 years , improvements ranged from 2 to 5 points , except for role physical ( 13.25 ) . A ceiling effect was detected on some WOMAC domains as well as a floor effect on the SF-36 . The MCID ranged from 25.91 ( stiffness ) to 29.26 ( pain ) on the WOMAC and from 10.78 ( physical role ) to 20.40 ( physical function ) on the SF-36 . The MDC ranged from 21.38 ( pain ) to 27.98 ( stiffness ) on the WOMAC and from 18.99 ( physical function ) to 42.05 ( social function ) on the SF-36 . CONCLUSIONS These values indicate expected gains after THR . However , the MCID and MDC values must be viewed cautiously due to the uncertainty of these estimators and should not be considered as absolute thresholds There has been little clinical research to examine the effects of patient positioning and pelvic motion on the alignment of the acetabular implant during total hip replacement surgery . Until now , no tools were capable of accurately measuring these variables during the actual procedure . As part of a broader program in medical robotics and computer assisted surgery , a clinical system has been developed that includes several enabling technologies . The hip navigation system ( HipNav ) continuously and precisely measures pelvic location and tracks relative implant alignment intraoperatively . HipNav technology is used to gauge current clinical practice and provide intraoperative feedback to surgeons with the goal of improving the precision and accuracy of acetabular alignment during total hip replacement . This system provides surgeons with a new class of image guided measurement tools and assist devices . These tools successfully were introduced into the clinical practice of surgery with results showing the following : ( 1 ) There exist unpredictable and large variations in the initial position of patients ' pelves on the operating room table and significant pelvic movement during surgery and during intraoperative range of motion testing ; ( 2 ) current mechanical acetabular alignment guides do not account for these variations , and result in variable and in the majority of cases unacceptable acetabular alignment ; and ( 3 ) press fitting oversized acetabular components influences the final cup orientation Objective : To compare responsiveness of the Harris Hip Score with generic measures ( that is , the Short Form-36 ( SF-36 ) , and a test of walking speed and pain during walking ) in patients with osteoarthritis ( OA ) of the hip . Method : The first 75 cases within the population of a r and omised clinical trial on manual therapy and exercise therapy  were selected for secondary analysis . Experienced ( self reported ) recovery by the patients after treatment ( five weeks ) was used as an external criterion for clinical ly relevant improvement . Responsiveness was evaluated by comparing responsiveness ratios and receiver operating characteristic curves . Results : The responsiveness ratio for the Harris Hip Score was high ( 1.70 ) compared with walking speed ( 0.45 ) , pain during walking ( 0.66 ) , and the subscales of the SF-36—“bodily pain ” ( 0.42 ) and “ physical functioning ” ( 0.36 ) . The area under the curve also was highest for the Harris Hip Score ( 0.92 ) compared with walking speed ( 0.71 ) , pain during walking ( 0.73 ) , and the SF-36 subscales — bodily pain and physical functioning ( both 0.66 ) . Conclusion : The Harris Hip Score  is more responsive than the test of walking speed , pain , and subscales for function of the SF-36 in patients with OA of the hip . The Harris Hip Score seems to be a suitable instrument to evaluate change in hip function in patients with OA of the hip Surgical approaches to the hip for total hip arthroplasty ( THA ) are termed minimally invasive when allowing for a skin incision length of 10 cm or less . The aim of this study was to explore if a minimally invasive posterior approach compared to a classic anterolateral approach negatively influenced surgical time , blood loss , implant position , or perioperative complications .  Two groups of THA patients mainly differing with respect to the surgical approach were compared . Results of 76 consecutive THA via a posterior mini-incision approach were recorded prospect ively and those of 76 controls operated via a classic anterolateral approach were recorded retrospectively .  THA was performed by the same surgeon in every case . Surgical time or intraoperative blood loss were not different among the groups . Total 24-h blood loss was significantly less in patients undergoing THA via minimally invasive posterior  approaches . Median cup inclination was 45 degrees in both groups . Cup anteversion was 15 degrees ( classic anterolateral ) and 12 degrees ( minimally invasive posterior ) , respectively . Stem position was regarded as neutral in 80 % of THA through classic anterolateral and in 76 % through minimally invasive dorsal incisions . Complications occurred in 8 % ( classic anterolateral ) and 9 % ( minimally invasive posterior ) of THA patients . Surgical time , blood loss , risk of malpositioned implants , or complications were not increased for THA patients operated through minimally invasive posterior incisions compared to those operated via classic anterolateral approaches In a prospect i ve r and omised clinical study  acetabular components were implanted either freeh and ( n = 30 ) or using CT-based ( n = 30 ) or imageless navigation ( n = 30 ) . The position of the component was determined post-operatively on CT scans of the pelvis . Following conventional freeh and placement of the acetabular component , only 14 of the 30 were within the safe zone as defined by Lewinnek et al ( 40 degrees inclination sd 10 degrees ; 15 degrees anteversion sd 10 degrees ) . After computer-assisted navigation 25 of 30 acetabular components ( CT-based ) and 28 of 30 components ( imageless ) were positioned within this limit ( overall p < 0.001 ) . No significant differences were observed between CT-based and imageless navigation ( p = 0.23 ) ; both showed a significant reduction in variation of the position of the acetabular component compared with conventional freeh and arthroplasty ( p < 0.001 ) . The duration of the operation was increased by eight minutes with imageless and by 17 minutes with CT-based navigation . Imageless navigation proved as reliable as that using CT in positioning the acetabular component BACKGROUND Malpositioning of the acetabular component during total hip arthroplasty increases the risk of dislocation , reduces the range of motion , and can be responsible for early wear and loosening . The purpose of this study was to compare computer-assisted with freeh and insertion of the acetabular component . METHODS A r and omized , controlled , matched prospect i ve study of two groups of thirty patients each was performed . In the first group , cup positioning was assisted by an imageless computer-assisted surgical system based on bone morphing . In the control group , the cup was placed freeh and . All of the patients were operated on by the same surgeon through an anterolateral approach . Cup anteversion and abduction angles were measured on three-dimensional computed tomography reconstructions postoperatively for each patient by an independent observer using special cup-evaluation software . RESULTS There were sixteen men and fourteen women in each group , and the mean body-mass index was approximately 25 in each group . The computer-assisted procedure took a mean of twelve minutes longer than the freeh and procedure . Fifty-seven percent ( seventeen ) of the thirty cups placed freeh and and 20 % ( six ) of the thirty in the computer-assisted group were outside of the defined safe zone ( outliers ) . This difference was significant ( p = 0.002 ) . There were no differences between the computer-assisted group and the freeh and -placement group with regard to the mean abduction and anteversion angles , but there was a significant heterogeneity of variances , with the lowest variations in the computer-assisted group . CONCLUSIONS Use of an imageless navigation system can improve cup positioning in total hip arthroplasty by reducing the percentage of outliers Optimal orientation of the acetabular component of a  total hip prosthesis  is an important factor in determining the early and long-term result of a  total hip arthroplasty ( THA ) . Conventional positioning of the cup component is usually done using a free-h and method , or with the help of a mechanical acetabular alignment guide . However , these methods have proven to be inaccurate , and a great variation in orientation of the cup is found postoperatively . In this study , we wished to determine if the variability of the abduction angle of acetabular cups could be reduced with the use of computer navigation . The abduction angles of the acetabular components of three groups of 50 THAs were assessed . In the first group , a free-h and method was used to position the cup component . This group was operated in the period before we started using computer navigation for hip surgery . In the second group , CT-based computer navigation was used to plan and help position the cup . The third group consisted of 50 THA cases in which a free-h and method was used to position the cup , although these procedures were performed in the period after we had begun using the Computer Assisted Surgery ( CAS ) system . The variability in cup abduction angle was assessed in all three groups and compared . There was a significant reduction in variability in the CAS group compared to the first group . There was also a reduction in variability in the CAS group compared to the third group , although this was not statistically significant . It is concluded that the use of computer navigation helped the surgeon to place the cup component with less variability of the abduction angle , and , more importantly , we found that no cups were placed in the more extreme positions ( outliers ) Minimally invasive ( MI ) total hip replacement ( THR )  supposedly provides improved ambulation in the immediate post-operative period . This study used a prospect i ve blinded design to analyse early post-operative walking ability using gait analysis . Seventeen patients were available for full analysis with nine having had the MI technique and eight having the st and ard incision ( SI ) technique .  Patients were blinded as to the incision used , as were all physiotherapists and assessors . Differences in temporal-spatial variables and joint kinematics measured 1 day pre-operatively , 2 days post-operatively and 42 days ( 6 weeks ) post-operatively were compared between groups . There was no significant difference in velocity , step length of the affected or unaffected leg , stride length or stance phase duration between the MI and SI groups between any of the timepoints tested . There was no significant improvement in the gait kinematics of the MI group compared to the SI group either 2 days post-operatively or 6 weeks post-operatively . Contrary to previous studies , there was no improvement in early post-operative gait for those patients who received THR using the minimally invasive technique Objective : To compare the results of single-incision minimally invasive total hip replacement ( ≤ 10 cm ) to st and ard-incision ( 16 cm ) total hip replacement in the early postoperative period with respect to functional and mobilizing ability ( transfers , mobilizing , walking and stair assessment ) . Setting : Orthopaedic wards of a regional orthopaedic centre . Subjects : Two hundred and nineteen total hip replacement patients were tested between December 2003 and June 2004 . Interventions : Patients were r and omized to either total hip replacement through a minimally invasive ( ≤ 10 cm ) or st and ard incision ( 16 cm ) . A single surgeon performed all procedures using the same type of component fixation . Postoperative physiotherapy assessment and treatment was st and ardized . Analgesia was also st and ardized . All patients , physiotherapy staff and assessors were blinded to the incision used . Main outcome measures : Patients were tested two days post operatively and were assessed for the following activities : transfer from supine to sit , transfer from sitting to st and ing , mobilizing , ascending and descending stairs and weight-bearing . Results : The shorter incision offered no significant improvement in patient ability in relation to transfer from lying to sitting , transfer from sitting to st and ing , mobilizing or weight-bearing . Ascending/descending stairs gave a total time for the minimal incision of 38.7 s against 40.8 s for a st and ard incision . There was no difference in walking velocity between the st and ard incision and minimal incision groups two days post operatively ( minimal incision = 0.26 m/s versus st and ard incision = 0.26 m/s ) or six weeks post operatively ( minimal incision = 0.90 m/s versus st and ard incision = 0.93 m/s ) . There was no difference between groups with respect to walking aids at six-week review . The mean length of stay for the minimally invasive approach was 3.65 days ( SD 2.04 ) against 3.68 days ( SD 2.45 ) for the st and ard approach . This was not significantly different . Conclusion : Total hip replacement performed through a minimally invasive incision of ≤ 10 cm compared with a st and ard incision of 16 cm offers no significant benefit in terms of the rate or ability of patients to mobilize and perform functional tasks necessary for safe discharge This prospect i ve study compares a mini-incision technique and traditional posterior approach for total hip arthroplasty ( THA ) . Thirty-three patients who had undergone a mini-incision THA were matched by diagnosis , gender , average age , and preoperative Harris Hip Score ( HHS ) to 33 patients who had undergone THA using the traditional posterior approach .  The average length of the incision for group 1 was 11.7 cm ( range , 7.3 - 13.0 ) and for group 2 was 20.2 cm ( range , 14.8 - 26.0 ) . At the 3-month follow-up , patients in the mini-incision group had significant improvement in limp ( P<.05 ) and ability to climb stairs ( P < .01 ) compared with the traditional group . At the 6 month follow-up , the mini-incision group was significantly better in terms of limp ( P < .05 ) , distance walked ( P<.001 ) , and stairs ( P < 0.001 ) . There was no significant difference between groups for pain , function , or range of motion at the 1-year follow-up examination The purpose of this prospect i ve r and omized study was to compare the early results of primary total hip arthroplasties performed with a minimally invasive technique or a st and ard technique . A consecutive series of 70 patients who underwent primary bilateral simultaneous total hip arthroplasties was studied . All procedures were performed through a posterolateral approach . Operative times and duration of hemovac drains were significantly shorter in the group with a minimally invasive technique ( P < .05 ) . However , there was a risk of infection when using this technique . There were no any late transfusions in any of our patients postdischarge . This minimally invasive technique did not offer any advantages because the results were not different , and in our h and s , it increased our infection rate Patients without prior hip surgery and body mass index lower than 30 undergoing primary total hip arthroplasty were eligible to participate in a r and omized prospect i ve study comparing a minimally invasive with a st and ard approach . The patients were r and omized  to receive incisions  of 8 cm ( group A , n = 28 ) or 15 cm ( group B , n = 32 ) . The groups were similar demographically . Patients in group A had significantly less intraoperative blood loss ( P < .003 ) and less total blood loss ( P < .009 ) . Fewer patients in group A limped at 6 weeks ( P < .04 ) . Operative time , transfusion requirements , narcotic usage , length of hospital stay , achievement of rehabilitation milestones , cane usage , and complications were similar in both groups . There was no difference between the groups at 1- and 2-year follow-up . Compared with a st and ard incision , patients who underwent a minimally invasive total hip arthroplasty demonstrated decreased blood loss and limped less at 6-week follow-up BACKGROUND Few prospect i ve r and omized studies have demonstrated benefits of minimally invasive total hip arthroplasty when compared with conventional total hip arthroplasty . We hypothesized that patients treated with a posterior mini-incision would have better results than those treated with a posterior long incision with regard to the achievement of established goals for pain relief and functional recovery permitting hospital discharge by the second postoperative day . METHODS Sixty of 231 eligible patients were r and omized ( with thirty in each group ) to have a total hip arthroplasty performed through either a posterior mini-incision ( 10 + /- 2 cm ) or a traditional long incision ( 20 + /- 2 cm ) . After completion of the total hip arthroplasty , the mini-incision group underwent extension of the skin incision to 20 cm . Patients were evaluated on the basis of self-determined pain scores , requirements for pain medicine , need for assistive gait devices , and time until discharge . Gait analysis provided objective functional assessment . RESULTS The average hospital stay was 63.2 + /- 13.3 hours in the mini-incision group and 73.6 + /- 23.5 hours in the long-incision group ( p = 0.04 ) . More patients with a mini-incision were discharged by the second postoperative day ( p = 0.003 ) and more were using just a single assistive device at the time of discharge ( p = 0.005 ) . As scored on a verbal analog scale of 0 to 10 points , patients with a mini-incision had less pain on each postoperative day and the pain score remained significantly lower at the time of discharge ( mean , 2.2 + /- 1.0 points compared with 3.1 + /- 0.9 points in the long-incision group ; p = 0.002 ) . After hospital discharge , there were no clinical differences in pain or function between the two groups of patients . CONCLUSIONS Compared with conventional total hip arthroplasty performed through a posterior incision , posterior minimally invasive total hip arthroplasty result ed in better early pain control , earlier discharge to home , and less use of assistive devices . Subsequent evaluations at six weeks and three months showed equivalency between the clinical results in the two groups . LEVEL OF EVIDENCE Therapeutic Level Abstract Despite the high number of total hip arthroplasty ( THA )  procedures performed each year , there is no common consensus on the best surgical approach . Gait is known to improve following THA although it does not return to what is typically quantified as normal , and surgical approach is believed to be a contributing factor . The current study evaluates post-operative hip function  and provides an objective assessment following two common surgical approaches : the McFarl and —Osborne direct lateral and the southern posterior .  Faced with the common problem of providing an objective comparison from the wealth of data collected using motion analysis techniques , the current study investigates the application of an objective classification tool to provide information on the effectiveness of each surgery and to differentiate between the characteristics of hip function following the two approaches . Seven inputs for the classifier were determined through statistical analysis of the biomechanical data . The posterior approach group exhibited greater characteristics of non-pathological gait and displayed a greater range of functional ability as compared with the lateral approach cohort . The classification tool has proved to be successful in characterizing non-pathological and THA function but was insufficient in distinguishing between the two surgical cohorts
target: Strong evidence was found for a decrease in operative time and intraoperative blood loss for MIS THA , with no difference in complication rates and risk for acetabular outliers .
  Strong evidence exists that there is no difference in physical functioning , measured either by question naires or by gait analysis .
  Moderate evidence was found for a shorter length of hospital stay after MIS THA .
  Conflicting evidence was found for a positive effect of MIS THA on pain in the early postoperative period , but that effect diminished after three months postoperatively .
  Strong evidence was found for an increase in operative time for CAS THA , and limited evidence was found for a decrease in intraoperative blood loss .
  Furthermore , strong evidence was found for no difference in complication rates , as well as for a significantly lower risk for acetabular outliers .
  Conclusions The results indicate that MIS THA is a safe surgical procedure , without increases in operative time , blood loss , operative complication rates and component malposition rates .
  However , the beneficial effect of MIS THA on functional recovery has to be proven .
  The results also indicate that CAS THA , though result ing in an increase in operative time , may have a positive effect on operative blood loss and operative complication rates .
  More importantly , the use of CAS results in better positioning of acetabular component of the prosthesis
background: Background Both minimally invasive surgery ( MIS ) and computer-assisted surgery ( CAS ) for total hip arthroplasty ( THA ) have gained popularity in recent years .
  We conducted a qualitative and systematic review to assess the effectiveness of MIS , CAS and computer-assisted MIS for THA .