***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: BACKGROUND A prospect i ve study was conducted to compare the effect of an anterolateral approach in the supine position ( ALS ) with that of a direct lateral ( DL ) approach on gait motion , including trunk deflection , in walking after total hip arthroplasty . We hypothesized that trunk deflection in walking after ALS would be significantly improved in comparison with use of the DL approach . METHODS The subjects were 15 patients , with 7 in the ALS group and 8 in the DL group . Walking before and 9 and 28 weeks after surgery was analyzed using 3-dimensional motion analysis . RESULTS Walking velocity , stride length , hip joint range of motion in the sagittal plane in walking , and locomotion range of trunk inclination were significantly improved 28 weeks after surgery in both groups . In gait analysis , there were no significant differences between the 2 groups . CONCLUSION This study was conducted to compare the effect of ALS with that of a DL approach on locomotion in walking after total hip arthroplasty . Hip pain at 9 weeks after surgery was significantly improved using ALS compared to the DL approach , but there were no significant differences in gait function at 28 weeks after surgery using ALS or DL approach . Further long-term studies are required to examine differences between these procedures Introduction Minimally invasive total hip arthroplasty ( THA ) is cl aim ed to be superior to the st and ard technique , due to the potential reduction of soft tissue damage via a smaller and tissue-sparing approach . As a result of the lack of objective evidence of fewer muscle and tendon defects , controversy still remains as to whether minimally invasive total hip arthroplasty truly minimizes muscle and tendon damage . Therefore , the objective was to compare the influence of the surgical approach on abductor muscle trauma and to analyze the relevance to postoperative pain and functional recovery . Material s and methods Between June 2006 and July 2007 , 44 patients with primary hip arthritis were prospect ively included in the study protocol . Patients underwent cementless unilateral total hip arthroplasty either through a minimally invasive anterolateral approach ( ALMI ) ( n = 21 ) or a modified direct lateral approach ( mDL ) ( n = 16 ) . Patients were evaluated clinical ly and underwent MR imaging preoperatively and at 3 and 12 months postoperatively . Clinical assessment contained clinical examination , performance of abduction test and the survey of a function score using the Harris Hip Score , a pain score using a numeric rating scale ( NRS ) of 0–10 , as well as a satisfaction score using an NRS of 1–6 . Additionally , myoglobin and creatine kinase were measured preoperatively , and 6 , 24 and 96 h postoperatively . Evaluation of the MRI images included fatty atrophy ( rating scale 0–4 ) , tendon defects ( present/absent ) and bursal fluid collection of the abductor muscle . Results Muscle and tendon damage occurred in both groups , but more lateral gluteus medius tendon defects [ mDL 3/12mth . : 6 (37%)/4 ( 25 % ) ; ALMI : 3 (14%)/2 ( 9 % ) ] and muscle atrophy in the anterior part of the gluteus medius [ mean-st and ard ( 12 ) : 1.75 ± 1.8 ; mean-MIS ( 12 ) : 0.98 ± 1.1 ] were found in patients with the mDL approach . The clinical outcome was also poorer compared to the ALMI group . Significantly , more Trendelenburg ’s signs were evident and lower clinical scores were achieved in the mDL group . No differences in muscle and tendon damage were found for the gluteus minimus muscle . A higher serum myoglobin concentration was measured 6 and 24 h postoperatively in the mDL group ( 6 h : 403 ± 168 μg/l ; 24 h : 304 ± 182 μg/l ) compared to the ALMI group ( 6 h : 331 ± 143 μg/l ; 24 h : 268 ± 145 μg/l ) . Conclusion Abductor muscle and tendon damage occurred in both approaches , but the gluteus medius muscle can be spared more successfully via the minimally invasive approach and is accompanied by a better clinical outcome . Therefore , going through the intermuscular plane , without any detachment or dissection of muscle and tendons , truly minimizes perioperative soft tissue trauma . Furthermore , MRI emerges as an important imaging modality in the evaluation of muscle trauma in THA BACKGROUND  Total hip replacement  using a minimally invasive surgical approach is cl aim ed to enable recovering of motor function more quickly . The purpose of this prospect i ve As per the stylesheet , kindly provide section headings for abstract . and r and omized study was to test this cl aim by evaluating early patient functional outcomes by gait analysis . METHODS Seventeen patients were operated on using a traditional anterolateral approach ( AL ) , 16 using a minimally invasive direct anterior approach ( DA ) .  Gait analysis was performed the day before surgery , and at 6 and 12 weeks after surgery . Time-distance and kinematics analyses were performed by a recently proposed anatomically-based gait analysis protocol . A static double-leg stance and five walking trials at self-selected speeds were recorded on a 9-m walkway . FINDINGS At 6 weeks follow-up , but in the DA group only , a statistically significant improvement with respect to preoperative status was observed for the percentage of single support and for the stride time . Between 6- and 12-week follow-up , the DA group showed a significant improvement in cadence , stride time and length , walking speed , hip flexion at foot contact , maximum hip flexion in swing , and hip total range of motion in the sagittal and the coronal planes . Between 6 and 12 weeks , the AL group showed significant improvements in opposite foot contact and step time , and in flexion at foot contact , maximum flexion in swing , and range of flexion at the hip joint . INTERPRETATION Minimally invasive DA patients improved in a larger number of gait parameters than patients receiving the traditional AL approach . The majority of improvements occurred between the 6- and 12-week follow-ups OBJECTIVE To investigate the differences in gait biomechanics on the basis of surgical approach 1 year after surgery .  DESIGN This was a descriptive laboratory study to investigate the side-to-side differences in walking mechanics at a self-selected walking speed as well as a functional assessment 1 year after total hip arthroplasty ( THA ) .  Temporospatial , kinetic , and kinematic data as well as functional outcomes were collected . Two-way analysis of variance was used to assess for between-group differences and limb-to-limb asymmetries . SETTING A controlled laboratory study . PARTICIPANTS This study examined 35 patients with primary , unilateral THA . The THA surgical approaches that were used in these patients included 12 direct lateral , 18 posterior , and 11 anterolateral . All the patients were assessed 1 year after THA . Patients were excluded from the study if they had contralateral hip pain or pathology , or any prior lower extremity total joint replacements . MAIN OUTCOME MEASUREMENTS Three-dimensional lower extremity kinematics and kinetics as well as spatiotemporal variables were collected . In addition , a series of physical performance measures were collected . RESULTS No main effects for the physical performance measures or biomechanical variables were observed among the approach groups . Significant limb-to-limb asymmetries were observed among all the patients , with decreased sagittal plane range of motion , peak extension , and peak vertical ground reaction forces on the operative side . CONCLUSION The results of this study indicated that no significant differences existed among the different surgical approach groups for any study variable . However , 1 year after THA , the patients demonstrated asymmetric gait patterns regardless of surgical approach , which indicated the potential need for continued intervention through physical therapy to regain normal side-to-side symmetry after THA 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 BACKGROUND Minimally invasive total hip arthroplasty is purported to allow an improved and faster rehabilitation in the immediate postoperative period because of reduced soft-tissue damage compared with total hip arthroplasty performed with use of a st and ard approach . In the present study , a minimally invasive approach was compared with a traditional st and ard approach in terms of the effect on gait kinematics as demonstrated with gait analysis and electromyography . METHODS Twenty r and omized patients who underwent a primary total hip replacement with use of a minimally invasive modified Watson-Jones approach ( minimally invasive group ) were compared with a group of twenty patients who underwent a total hip arthroplasty with use of a st and ard transgluteal Hardinge approach ( st and ard group ) . All patients received the same cementless implant , inserted with use of st and ard instruments , and all operations were performed by a single , experienced surgeon . The patients were evaluated with use of three-dimensional gait analysis and dynamic electromyograms at three time points : preoperatively , ten days postoperatively , and twelve weeks postoperatively . Temporospatial and joint-kinematic parameters were evaluated . RESULTS There were no significant differences between the two groups with regard to the temporospatial variables of velocity , cadence , step length , and stride length at any tested time point . With regard to the range of motion of the operatively treated hip , the minimally invasive group had a smaller decrease at the ten-day time point in comparison with the st and ard group . However , this finding was not significant . The reduction in the range of motion was mainly caused by reduced hip extension . A compensatory increase in the pelvic tilt was observed in both groups . One patient in the st and ard group showed a positive Trendelenburg gait ten days postoperatively ; it had disappeared completely at the twelve-week time point . CONCLUSIONS With regard to gait kinematics in the early postoperative period ( three months ) , the present study showed no significant benefit for patients who underwent a total hip arthroplasty through a minimally invasive Watson-Jones approach in comparison with those who were managed with a st and ard transgluteal approach Purported advantages of total hip arthroplasty performed with minimally invasive surgical ( MIS ) approaches are less muscle damage and faster recovery . There are little data scientifically evaluating these cl aims . Twenty-four consecutive hips were r and omized to total hip arthroplasty through 1 of 3 MIS approaches ( 2-incision , mini-posterior , and mini-anterolateral ) . Each patient underwent preoperative and postoperative gait analysis . Gait parameters included vertical ground reaction force , velocity , single-leg stance time , limb-loading rate , and abductor torque . All 3 groups demonstrated overall improvements in gait parameters at 6 weeks postoperatively . The anterolateral approach patients showed a decrease in the vertical ground reaction force at mid-stance , whereas the 2-incision and posterior approaches demonstrated no significant change . These results fail to demonstrate any significant advantage of the 2-incision approach over the posterior approach in kinetic gait parameters . Furthermore , the anterolateral approach demonstrates a gait pattern consistent with abductor muscle injury in the early recovery period , despite the MIS approach AIM Different surgical approaches are used in total hip arthroplasty . The present study confronted two surgical techniques , analysing functional recovery in terms of activities of daily living , and ambulation using gait analysis , after a st and ardized rehabilitation protocol . Our hypothesis was that the increased surgical damage could modify the gait pattern and functional recovery . METHODS Thirty patients were r and omly assigned to two homogeneous groups : Group A was treated with intermuscular minimally invasive surgery ( MIS ) ; Group B was treated with st and ard lateral transmuscular approach . Follow up was planned at 30 and 90 days . Instrumental evaluation using gait analysis and functional evaluation using vali date d scales were performed at follow up . RESULTS No differences could be found as for functional scales . At the first follow up , the MIS approach proved to be the most favourable : data showed a longer duration of the swing phase , an improved range of motion of the non-treated hip , a reduced adduction ( all P<0.005 ) and a correct timing of activation of the gluteus medium muscle on the treated side . At the second evaluation , gait analysis demonstrated some benefits of the intermuscular approach ( a better flexion of both hips , and a minor obliquity of the pelvis during the terminal stance ) , but also advantages in the transmus 
    Output:
    
Conclusions In this meta- analysis , gait speed and peak hip flexion within 3 months after surgery were significantly higher in the DAA group than in the ALA group .