***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background : The optimal graft choice of  anterior cruciate ligament ( ACL ) reconstruction  remains controversial . Purpose : To compare the outcomes , especially the long-term cumulative failure rate , of ACL reconstruction using either synthetics with remnant preservation or hamstring autografts ( 4-str and semitendinosus and gracilis tendons ) . Study Design : Cohort study ; Level of evidence , 2 . Methods : A total of 133 patients who underwent ACL reconstruction ( synthetics : n = 43 ; hamstring autografts : n = 90 ) between July 2004 and December 2007 were included . Question naires ( Tegner activity scale , Lysholm knee scale , and International Knee Documentation Committee [ IKDC ] subjective form ) were completed preoperatively and at 6 months , 1 year , 5 years , and 10 years postoperatively . The Knee injury and Osteoarthritis Outcome Score ( KOOS ) was additionally applied at 10 years ’ follow-up . The physical examination was based on the 2000 IKDC form . The manual maximum side-to-side difference ( KT-1000 arthrometer ) , single-hop test , thigh muscle atrophy , and joint degeneration ( Kellgren and Lawrence classification ) were evaluated . The Kaplan-Meier curve and log-rank test ( Mantel-Cox , 95 % CI ) were used to compare graft survivorship . Results : Ten years postoperatively , 111 patients were available , with 38 ( 88.4 % ) patients ( mean age , 27.6 ± 9.3 years ; 28 men ) with synthetics and 73 ( 81.1 % ) patients ( mean age , 28.6 ± 8.8 years ; 64 men ) with hamstring autografts . Among them , 104 patients  ( synthetics : n = 35 [ 81.4 % ] ; hamstring autografts : n = 69 [ 76.7 % ] ) completed subjective evaluations , and 89 patients ( synthetics : n = 30 [ 69.8 % ] ; hamstring autografts : n = 59 [ 65.6 % ] ) completed objective evaluations . For hamstring autografts and synthetics , the cumulative failure rates were 8.2 % and 7.9 % , respectively , and the log-rank test demonstrated no significant difference between the 2 Kaplan-Meier survival curves ( P = .910 ) . At 6 months postoperatively , for hamstring autografts and synthetics , the mean Lysholm score was 83.0 ± 7.8 and 88.1 ± 7.5 , respectively ( P < .001 ) ; the mean IKDC score was 83.8 ± 7.8 and 86.9 ± 4.5 , respectively ( P = .036 ) ; and the mean Tegner score was 3.7 ± 1.1 and 5.0 ± 1.5 , respectively ( P < .001 ) . At 1 year postoperatively , the mean Tegner score was 5.5 ± 1.9 and 6.5 ± 2.0 , respectively ( P = .011 ) . No statistically significant difference was observed on other subjective evaluation findings , physical examination findings ( overall IKDC grade A : 45.8 % of hamstring autografts , 50.0 % of synthetics ) , side-to-side difference ( 1.5 ± 1.5 mm for synthetics , 2.4 ± 2.1 mm for hamstring autografts ) , single-hop test findings ( grade A : 84.7 % of hamstring autografts , 93.3 % of synthetics ) , grade A/B thigh muscle atrophy ( 88.1 % of hamstring autografts , 93.3 % of synthetics ) , ipsilateral radiographic osteoarthritis ( 55.9 % of hamstring autografts , 50.0 % of synthetics ) , and graft survivorship . Conclusion : In this prospect i ve cohort study , primary ACL reconstruction using either synthetics with remnant preservation or hamstring autografts showed satisfactory outcomes , especially the long-term cumulative failure rate , at 10 years postoperatively . Patient-reported outcomes suggested that symptom relief and restoration of function might occur earlier in those with synthetics Background Injury to the anterior cruciate ligament ( ACL ) of the knee is common . Following complete rupture of the ACL , insufficient re-vascularization of the ligament prevents it from healing completely , creating a need for reconstruction . A variety of grafts are available for use in ACL reconstruction surgery , including synthetic grafts . Over the last two decades new types of synthetic ligaments have been developed . One of these synthetic ligaments , the Ligament Advanced Reinforcement System ( LARS ) , has recently gained popularity . The aim of this systematic review was to assess the current best available evidence for the effectiveness of the LARS as a surgical option for symptomatic , anterior cruciate ligament rupture in terms of graft stability , rehabilitation time and return to pre-injury function . Method This systematic review included studies using subjects with symptomatic , ACL ruptures undergoing LARS reconstruction .  A range of electronic data bases were search ed in May 2010 . The method ological quality of studies was appraised with a modified version of the Law critical appraisal tool . Data relating to study characteristics , surgical times , complication rates , outcomes related to knee stability , quality of life , function , and return to sport as well as details of rehabilitation programs and timeframes were collected . Results This review identified four studies of various design s , of a moderate method ological quality . Only one case of knee synovitis was reported . Patient satisfaction with LARS was high . Graft stability outcomes were found to be inconsistent both at post operative and at follow up periods . The time frames of rehabilitation periods were poorly reported and at times omitted . Return to pre-injury function and activity was often discussed but not reported in results . Conclusions There is an emerging body of evidence for LARS with comparable complication rates to traditional surgical techniques , and high patient satisfaction scores . However , this systematic review has highlighted several important gaps in the existing literature that require future prospect i ve investigation . The findings of this review were equivocal with regards to other measures such as graft stability and long term functional outcomes . While the importance of rehabilitation following LARS is well recognised , there is limited evidence to guide rehabilitation protocol We have undertaken a r and omised clinical trial comparing two methods of reconstruction of the anterior cruciate ligament in patients with chronic instability . We used an ipsilateral bone-patellar-tendon-bone autograft in 27 patients and the Ligament Advancement Reinforcement System ( LARS ) artificial ligament in 26 . Assessment before and at two , six , 12 and 24 months after surgery , included the history , physical examination , a modified International Knee Documentation Committee ( IKDC ) score , the Tegner score , the Knee Injury and Osteoarthritis Outcome Score ( KOOS ) and instrumented laxity testing . There were no cases of reactive synovitis or of infection of the knee , and there was no difference regarding the failure rate between the two groups . The IKDC showed no significant differences between the two groups at any stage of the follow-up . The KOOS evaluation showed consistently better results in all subscales for the LARS group during the first year of follow-up . After 24 months these differences were no longer evident . Instrument-tested laxity was greater in the LARS group at all stages of follow-up , but the differences were not significant at 24 months . Our findings suggest that at follow-up at 24 months the LARS ligament seems to be a satisfactory treatment option , especially when an early return to high levels of activity is dem and ed Purpose Several studies compare the short- and long-term results of anterior cruciate ligament ( ACL ) reconstruction using bone-patellar tendon-bone ( BPTB ) graft or double-looped semitendinosus and gracilis ( DLSG ) graft . However , no studies evaluate the long-term results of BPTB grafts fixed with metal interference screws and DLSG grafts fixed with the Bone Mulch Screw and the Washer Loc . This prospect i ve r and omized multicentre study has the null hypothesis that there is no difference in long-term outcome between the two procedures . Methods A total of 114 patients with a symptomatic ACL rupture were r and omized to reconstruction with either a BPTB graft ( N = 58 ) or a DLSG graft ( N = 56 ) . Follow-up was conducted after one , two and seven years . At the seven-year follow-up , 102 of the 114 patients ( 89 % ) were available for evaluation ; however , 16 of these by telephone-interview only . Results Ten patients in the BPTB group and 19 patients in the DLSG group underwent additional knee surgery ( P = 0.048 ) , two and three , respectively , of these were ACL revisions ( n.s . ) . The total flexion work was lower in the DLSG group ( P = 0.001 ) . The mean peak flexion torque and extension work , however , showed no difference between the groups . No significant differences were found between the groups regarding the Tegner activity score , the Lysholm functional score , the Knee injury and osteoarthritis outcome score ( KOOS ) , subjective knee function , anterior knee pain or mobility . There was no significant difference in laxity between the groups on the Lachman test or the KT-1,000 maximum manual force test . Conclusions Both grafts and fixation methods result ed in satisfactory subjective outcome and objective stability . Both these methods can therefore be considered as suitable alternatives for ACL reconstructions . Level of evidence II Background : Because of specific method ological difficulties in conducting r and omized trials , surgical research remains dependent predominantly on observational or non‐r and omized studies . Few vali date d instruments are available to determine the method ological quality of such studies either from the reader 's perspective or for the purpose of meta‐ analysis . The aim of the present study was to develop and vali date such an instrument OBJECTIVE To compare the therapeutic effect of  anterior cruciate ligament ( ACL ) reconstruction by means of four-str and semitendinosus tendon autograft and ligament advanced reinforcement system ( LARS ) by arthroscopy . METHODS From July 2002 to April 2005 , 42 patients underwent ACL reconstruction by arthroscopy . Twenty-seven patients were treated by four-str and semitendinosus tendon autograft ( semitendinosus tendon autograft group ) , including 22 males and 5 females , with the age from 20 years to 52 years . Among these patients , there were 12 sports injuries , 8 traffic accidents and 7 other injuries . There were 16 cases of left knees and 11 of right knees . The pre-operation Lysholm score was 50.70 + /- 6.68 , and the course of the disease was 2 to 12 months . Other 15 patients were treated by LARS artificial ligament ( LARS group ) , including 12 males and 3 females , with the age from 17 years to 40 years . Among these patients , there were 8 sports injuries , 4 traffic accidents and 3 other injuries . There were 6 cases of left knees and 9 of right knees . The pre-operation Lysholm score was 50.20 + /- 6.22 , and the course of the disease was 3 to 12 months . There was no statistically significant difference between the two groups ( P > 0.05 ) . The ranges of motion , stability and complication of the knee were evaluated during the follow-up . RESULTS All incisions healed at the first stage . The patients in the semitendinosus tendon autograft group were followed up for 22 months to 43 months , while 18 months to 40 months in the LARS group . There were 5 patients ( 19 % ) whose tensile gap was more than 3 mm when the max tensile force text was done in the semitendinosus tendon autograft group , and 3 patients ( 20 % ) in the LARS group . The Lysholm score was 87.80 + /- 3.41 in the semitendinosus tendon autograft autograft group , and 88.90 + /- 3.30 in the LARS group . There was no statistically significant difference between the two groups ( P > 0.05 ) . The final evaluation based on the improved Lysholm classification st and ard showed the choiceness rate was 92.6 % ( 18 excellent cases , 7 good cases and 2 fair cases ) in the semitendinosus tendon autograft group , and 93.3 % ( 11 excellent cases , 3 good cases , 1 fair case ) in the LARS group . There was no statistically significant difference between the two groups ( P > 0.05 ) . The joint motion capability evaluation , according to the Tegner st and ard , showed 3 to 6 class ( with the average class of 4.93 ) in the semitendinosus tendon autograft group , and 3 to 7 class ( with the average class of 5.03 ) in the LARS group . There was no statistically significant difference ( P > 0.05 ) . The knee extension in 2 cases was 5 degrees less than the normal , and in 5 cases 5 - 10 degrees less than the normal in the semitendinosus tendon autograft group . But in all cases in the LARS group , joint motion recovered to the normal ( P < 0.05 ) . There was no sign of synovitis in both 
    Output:
    
This systematic review comparing long‐term outcomes after cruciate ligament reconstruction with either autograft or synthetics suggests no significant differences in failure risk .
Autografts were inferior to synthetics with respect to restoring knee joint stability and patient‐reported outcome scores , and were also associated with more postoperative complications