***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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    ***EXAMPLES*** 
    Input: Background The choice of different graft types and surgical techniques used when reconstructing a torn anterior cruciate ligament may influence the long-term prevalence of osteoarthritis and functional outcomes . Hypothesis There are no differences in the prevalence of knee osteoarthritis or  knee function in patients undergoing reconstruction of a torn anterior cruciate ligament with 4-str and hamstring autograft versus patellar tendon — bone autograft .  Study Design R and omized controlled trial ; Level of evidence , 1 . Methods Seventy-two patients with subacute or chronic rupture of the anterior cruciate ligament were r and omly assigned to autograft reconstruction with 4-str and gracilis and semitendinosus tendon ( HAM ) ( N = 37 ) or with patellar tendon — bone ( PTB ) ( N = 35 ) from the ipsilateral side . Outcome measurements were the Cincinnati knee score , single-legged hop tests , isokinetic muscle strength tests , pain , knee joint laxity test ( KT-1000 arthrometer ) , and a radiologic evaluation ( Kellgren and Lawrence ) at 10-year follow-up . Results At 10 years , 57 patients ( 79 % ) were eligible for evaluation—29 in the HAM group and 28 in the PTB group . No differences were found between the 2 graft groups with respect to the Cincinnati knee score , the single-legged hop tests , pain , muscle strength measurements , or knee joint laxity . Fifty-five percent and 64 % of the patients had osteoarthritis corresponding to Kellgren and Lawrence grade 2 or more in the HAM and the PTB groups , respectively ( P = .27 ) . For the uninvolved knee , the corresponding numbers were 28 % and 22 % ( P = .62 ) . Conclusion At 10 years postoperatively , no statistically significant differences in clinical outcome between the 2 graft types were found . The prevalence of osteoarthritis was significantly higher in the operated leg than in the contralateral leg , but there were no significant differences between the 2 groups . The results indicate that the choice of graft type after an anterior cruciate ligament injury has minimal influence on the prevalence of osteoarthritis 10 years after surgery The aims of the study were to analyse the change in knee laxity over time after  anterior cruciate ligament ( ACL ) reconstruction  , using either bone – patellar – tendon – bone ( BPTB ) or hamstring ( HS ) tendon autografts , and to compare the knee laxity measurements between the study groups both pre-operatively and on multiple follow-up occasions . Another aim was to compare the radiographic findings in terms of degenerative changes between the study groups . A r and omised series of 71 patients , who underwent ACL reconstruction using BPTB or HS tendon autografts and interference screw fixation , were included in the study . Of these patients , 47/71 ( 66 % ) attended a clinical examination , including laxity measurements using the  KT-1000 arthrometer  , pre-operatively and on four post-operative occasions ; 6 months , 1 year , 2 years and 7 years after the reconstruction . The BPTB group consisted of 22 patients , while there were 25 patients in the HS group . There were no significant differences in the mean side-to-side knee laxity between the BPTB and the HS group pre-operatively or at the follow-up examinations . There was a tendency towards a reduction in side-to-side knee laxity over time in both groups , measured with the KT-1000 arthrometer . The decrease was significant when analysing the injured and uninjured knee separately ( injured side p < 0.001 ( BPTB ) and p = 0.005 ( HS ) , uninjured side p = 0.008 and p = 0.042 , respectively ) . Forty-four patients ( BPTB 21 , ST 23 ) underwent a radiographic assessment at the 7-year follow-up , which revealed no significant differences between the study groups in terms of osteoarthritic findings classified according to the Fairbank and Ahlbäck rating systems . In overall terms , osteoarthritis was identified in 16 % ( BPTB 19 % ; ST 13 % ; n.s . ) according to the Ahlbäck rating system and 68 % ( BPTB 67 % ; ST 70 % ; n.s . ) according to the Fairbank rating system . There were no significant differences in knee laxity measurements between the two study groups pre-operatively or at 7 years . A decrease in knee laxity over time was seen in both groups . There were no significant differences between the BPTB and ST groups in terms of osteoarthritic findings at 7 years BACKGROUND The American edition of The Journal of Bone and Joint Surgery ( JBJS-A ) has included a level-of- evidence rating for each of its clinical scientific papers published since January 2003 . The purpose of this study was to assess the type and level of evidence found in nine different orthopaedic journals by applying this level-of- evidence rating system . METHODS We review ed all clinical articles published from January through June 2003 in nine orthopaedic journals . Studies of animals , studies of cadavera , basic-science articles , review articles , case reports , and expert opinions were excluded . The remaining 382 clinical articles were r and omly assigned to three experienced review  ers and two  inexperienced review ers , who rated them with the JBJS-A grading system . Each review er determined whether the studies were therapeutic , prognostic , diagnostic , or economic , and each rated the level of evidence as I , II , III , or IV . Review ers were blinded to the grade s assigned by the other review ers . RESULTS According to the review ers ' ratings , 70.7 % of the articles were therapeutic , 19.9 % were prognostic , 8.9 % were diagnostic , and 0.5 % were economic . The review ers grade d 11.3 % as Level I , 20.7 % as Level II , 9.9 % as Level III , and 58.1 % as Level IV . The kappa values for the interobserver agreement between the experienced review ers and the inexperienced review ers were 0.62 for the level of evidence and 0.76 for the study type . The kappa values for the interobserver agreement between the experienced review ers were 0.75 for the level of evidence and 0.85 for the study type . The kappa values for the agreement between the review ers ' grade s and the JBJS-A grade s were 0.84 for the level of evidence and 1.00 for the study type . All kappa values were significantly different from zero ( p < 0.0001 for all ) . The percentage of articles that were rated Level I or II increased in accordance with the 2003 journal impact factors for the individual journals ( p = 0.0061 ) . CONCLUSIONS Orthopaedic journals with a higher impact factor are more likely to publish Level-I or II articles . The type and level of information in orthopaedic journals can be reliably classified , and clinical investigators should pursue studies with a higher level of evidence whenever feasible Background : Numerous studies have compared patellar tendon ( PT ) and hamstring tendon ( HS ) anterior cruciate ligament ( ACL ) reconstructions in the short to midterm , but fewer long-term results have been published . Hypothesis : There will be no difference in functional outcome between ACL reconstruction performed with PT and HS grafts , but PT grafts will have more donor site morbidity . Study Design : R and omized controlled trial ; Level of evidence , 1 . Methods : Sixty-five patients undergoing ACL reconstruction were r and omized to receive either a PT graft or a 4-str and HS graft . Early results were reported at 4 , 8 , 12 , 24 , and 36 months . Forty-seven patients ( 22 of 31 PT and 25 of 34 HS ) were review ed at a mean of 15.3 years . Results : Four graft ruptures ( 1 PT , 3 HS ) and 6 contralateral ACL injuries ( 4 PT , 2 HS ) occurred in the group that was review ed . There was no statistically significant difference between the groups for any of the variables measured . There was a similar incidence of anterior knee pain and kneeling pain in both groups . The previously observed increased extension deficit in the PT group at 3 years was not present at 15 years , and there was no significant between-group difference in knee laxity . A higher proportion of patients in the PT group were participating in sport on a weekly basis ( 73 % PT , 48 % HS ; P = .05 ) . There was no difference in the degree of osteoarthritis between the groups . Conclusion : This r and omized controlled trial showed that HS and PT ACL reconstructions have comparable results at an average 15-year follow-up . Contrary to the study hypothesis , some of the graft differences seen at earlier review were not present at 15 years , and patients with PT grafts were more active in sport participation . Overall , both graft types provided good long-term subjective and objective outcomes 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 The aim of the study was to compare the results after arthroscopic anterior cruciate ligament ( ACL ) reconstruction  using central -third bone-patellar tendon-bone ( BTB ) autografts and triple/quadruple semitendinosus ( ST ) autografts . HYPOTHESIS In the long-term , ACL reconstruction using BTB autografts will render more donor-site problems than ST autografts . STUDY DESIGN R and omized controlled trial ; Level of evidence , 1 . METHODS A r and omized series of 71 patients ( 22 women and 49 men ) with a unilateral ACL rupture who underwent reconstructive surgery were included in the study . The BTB graft was used in 34 patients ( BTB group ) and the ST-tendon graft was used in 37 patients ( ST group ) . The patients were examined a median of 86 months ( range , 68 to 114 months ) after the reconstruction . RESULTS Sixty-eight of 71 patients ( 96 % ) were examined at follow-up . The clinical assessment s at follow-up revealed no significant differences between the BTB group and the ST group in terms of the Lysholm score , Tegner activity level , International Knee Documentation Committee evaluation system , 1-legged hop test , KT-1000 arthrometer laxity measurements , manual Lachman test , and range of motion . A significant improvement was seen in both groups compared with the preoperative values in terms of most clinical assessment s. Donor-site morbidity in the form of knee-walking ability , kneeling ability , and area of disturbed anterior knee sensitivity revealed no significant differences between the groups . CONCLUSION Seven years after ACL reconstruction , the subjective and objective outcomes were similar after using the central -third BTB autograft and triple/quadruple ST autograft . Furthermore , no difference in terms of donor-site morbidity was found between the 2 groups Background : Patients generally choose to undergo  anterior cruciate ligament reconstruction ( ACLR )  to return to their active lifestyles . However , returning to their previous activity level may result in a retear of their reconstructed knee or an injury to their contralateral anterior cruciate ligament ( CACL ) . Purpose : To determine the risk factors associated with revision ACLR and contralateral ACLR ( CACLR ) , compare the survival of the reconstructed ACL with the CACL , and determine how the risk factors associated with revision ACLR compare with those for CACLR . Study Design : Cohort study ; Level of evidence , 3 . Methods : A ret 
    Output:
    
Conclusion : This systematic review comparing long-term outcomes after ACL reconstruction with either autograft BPTB or autograft HS suggests no significant differences in manual/instrumented laxity and graft failures between graft types .
An increase in long-term anterior knee pain , kneeling pain , and higher rates of osteoarthritis were noted with BPTB graft use