***TASK*** the task is to summarize an input biomedical literature in six sentences 
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    Input: Background Concomitant injuries to secondary structures have been proposed as a major cause of failure of anterior cruciate ligament reconstruction . Purpose Our purpose was to determine the relationship between meniscal status at the time of anterior cruciate ligament reconstruction and ultimate long-term function and stability . Study Design Prospect i ve cohort study . Methods We prospect ively studied 63 patients for an average of 10.4 years after arthroscopically assisted bone-patellar tendon-bone anterior cruciate reconstruction . All surgeries were performed between 1988 and 1991 ; concomitant meniscal surgery was performed if necessary . Subjects were divided into subgroups relative to the integrity of their menisci at the end of the reconstruction procedure ( intact meniscus , partial meniscectomy , complete meniscectomy ) . Results Patients who had undergone any degree of meniscal resection reported significantly more subjective complaints and activity limitations than those with intact menisci . Subjective International Knee Documentation Committee and Lysholm scores were lower in the meniscectomy subgroups than in the meniscus-intact group . Objective testing revealed a significantly lower ability to perform the single-legged hop in the meniscectomy subgroups . Ligament stability based on instrumented laxity measurements was not significantly different between the subgroups . Radiographic abnormalities were also more common in the subgroups that had undergone meniscectomy . Conclusions The menisci should be repaired if at all possible , especially in the setting of anterior cruciate ligament reconstruction , for optimal functional outcome and patient satisfaction BACKGROUND There are no controlled , prospect i ve studies comparing the 10-year outcomes of anterior cruciate ligament ( ACL ) reconstruction using patellar tendon ( PT ) and 4-str and hamstring tendon ( HT ) autografts . HYPOTHESIS Comparable results are possible with HT and PT autografts . STUDY DESIGN Cohort study ; Level of evidence , 2 . METHODS One hundred eighty ACL-deficient knees that met inclusion criteria underwent ACL reconstruction ( 90 HT autograft , 90 PT autograft ) by one surgeon and were treated with an accelerated rehabilitation program . All knees were observed in a prospect i ve fashion with subjective , objective , and radiographic evaluation at 2 , 5 , 7 , and 10-year intervals . RESULTS At 10 years , there were no differences in graft rupture rates ( 7/90 PT vs. 12/90 HT , P = .24 ) . There were 20 contralateral ACL ruptures in the PT group , compared with 9 in the HT group ( P = .02 ) . In all patients , graft rupture was associated with instrumented laxity > 2 mm at 2 years ( P = .001 ) . Normal or near-normal function of the knee was reported in 97 % of patients in both groups . In the PT group , harvest-site symptoms ( P = .001 ) and kneeling pain ( P = .01 ) were more common than in the HT group . More patients reported pain with strenuous activities in PT knees than in HT knees ( P = .05 ) . Radiographic osteoarthritis was more common in PT knees than the HT-reconstructed knees ( P = .04 ) . The difference , however , was composed of patients with mild osteoarthritis . Other predictors of radiographic osteoarthritis were < 90 % single-legged hop test at 1 year and the need for further knee surgery . An " ideal " outcome , defined as an overall International Knee Documentation Committee grade of A or B and a radiographic grade of A at 10 years after ACL reconstruction , was associated with <3 mm of instrumented laxity at 2 years , the absence of additional surgery in the knee , and HT grafts . CONCLUSIONS It is possible to obtain excellent results with both HT and PT autografts . We recommend HT reconstructions to our patients because of decreased harvest-site symptoms and radiographic osteoarthritis We used single-photon emission computed tomography ( SPECT ) to determine the long-term risk of degenerative change after reconstruction of the anterior cruciate ligament ( ACL ) . Our study population was a prospect i ve series of 31 patients with a mean age at injury of 27.8 years ( 18 to 47 ) and a mean follow-up of ten years ( 9 to 13 ) after bone-patellar tendon-bone reconstruction of the ACL .  The contralateral normal knee was used as a control . All knees were clinical ly stable with high clinical scores ( mean Lysholm score , 93 ; mean Tegner activity score , 6 ) . Fifteen patients had undergone a partial meniscectomy and ACL reconstruction at or before reconstruction of their ACL .  In the group with an intact meniscus , clinical symptoms of osteoarthritis ( OA ) were found in only one patient ( 7 % ) , who was also the only patient with marked isotope uptake on the SPECT scan compatible with OA . In the group which underwent a partial meniscectomy , clinical symptoms of OA were found in two patients ( 13 % ) , who were among five ( 31 % ) with isotope uptake compatible with OA . Only one patient ( 7 % ) in this group had evidence of advanced OA on plain radiographs . The risk of developing OA after ACL reconstruction in this series is very low and lower than published figures for untreated ACL-deficient knees . There is a significant increase ( p < 0.05 ) in degenerative change in patients who had a reconstruction of their ACL and a partial meniscectomy  compared with those who had a reconstruction of their ACL alone 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 In athletes ,  anterior cruciate ligament ( ACL ) reconstruction is recommended after injury to restore the normal knee function and allow subsequent return to sport . Successful ACL reconstruction with patellar tendon ( PT ) and hamstring tendon ( HT ) grafts combined with a well-structured rehabilitation program could bring athletes back to their previous level of sport activities . We prospect ively followed-up 100 athletes who underwent ACL reconstruction with either PT ( n=50 ) or HT grafts ( n=50 ) . Evaluation was done pre-operatively and post-operatively ( 3 , 6 , 12 , and 24 months ) using International Knee Documentation Committee ( IKDC ) , Lysholm , Noyes , and Tegner scales . Subjective assessment numeric evaluation ( SANE ) , knee activity rating scale ( Marx ) and a psychological profile question naire ( psychovitality ) were also utilized . Objective evaluations included isokinetic tests and computerized knee motion analysis . Data gathered were statistically analyzed using the Mann – Whitney non-parametric U-test . Among the 100 patients who have undergone ACL reconstruction  , 65 % returned to the same level of sports , 24 % changed sports and 11 % ceased sport activities . No significant difference ( P>0.05 ) in outcome between PT and HT grafts were observed . No significant differences ( P>0.05 ) were noted between athletes who “ returned ” to their previous sport and those who “ did not return ” to sports at the same level when using the IKDC , Lysholm , Noyes , and Tegner knee evaluation scales . However , significant difference was observed with the knee scores obtained by those who returned and those who completely ceased participation in sport activities . Computerized laxity test revealed that 90 % of these patients have less than 3 mm side-to-side difference with no significant difference between HT and PT groups . Patients who “ returned to sports ” obtained significantly better scores with the Marx scale ( P=0.001 ) and the psychovitality question naire ( P=0.001 ) than those who did not . Conventional knee scales including IKDC , Lysholm , Noyes , and Tegner remain as reliable means of evaluating outcome of ACL reconstruction . However , the data obtained from these are not sufficient to determine which among the patients who had knee reconstruction can successfully return to sport . The use of the Marx knee activity rating scale and the evaluation of the athletes ’ psychological profile are additional scales that can be useful in determining which among the patients treated have a better chance of returning to their pre-injury activity levels BACKGROUND The optimal management of a torn anterior cruciate ligament ( ACL ) of the knee is unknown . METHODS We conducted a r and omized , controlled trial involving 121 young , active adults with acute ACL injury in which we compared two strategies : structured rehabilitation plus early ACL reconstruction and structured rehabilitation with the option of later ACL reconstruction if needed . The primary outcome was the change from baseline to 2 years in the average score on four subscales of the Knee Injury and Osteoarthritis Outcome Score (KOOS)--pain , symptoms , function in sports and recreation , and knee-related quality of life ( KOOS(4 ) ; range of scores , 0 [ worst ] to 100 [ best ] ) . Secondary outcomes included results on all five KOOS subscales , the Medical Outcomes Study 36-Item Short-Form Health Survey , and the score on the Tegner Activity Scale . RESULTS Of 62 subjects assigned to rehabilitation plus early ACL reconstruction , 1 did not undergo surgery . Of 59 assigned to rehabilitation plus optional delayed ACL reconstruction , 23 underwent delayed ACL reconstruction ; the other 36 underwent rehabilitation alone . The absolute change in the mean KOOS(4 ) score from baseline to 2 years was 39.2 points for those assigned to rehabilitation plus early ACL reconstruction and 39.4 for those assigned to rehabilitation plus optional delayed reconstruction ( absolute between-group difference , 0.2 points ; 95 % confidence interval , -6.5 to 6.8 ; P=0.96 after adjustment for the baseline score ) . There were no significant differences between the two treatment groups with respect to secondary outcomes . Adverse events were common in both groups . The results were similar when the data were analyzed according to the treatment actually received . CONCLUSIONS In young , active adults with acute ACL tears , a strategy of rehabilitation plus early ACL reconstruction was not superior to a strategy of rehabilitation plus optional delayed ACL reconstruction . The latter strategy substantially reduced the frequency of surgical reconstructions . ( Funded by the Swedish Research Council and the Medical Faculty of Lund University and others ; Current Controlled Trials number , IS RCT N84752559 . We continued a prospect i ve longitudinal follow-up study of 53 remaining patients who underwent open total meniscectomy as adolescents and who at that time had no other intra-articular pathology of the knee . Their clinical , radiological and patient-reported outcomes are described at a mean follow-up of 40 years ( 33 to 50 ) . The cohort of patients who had undergone radiological evaluation previously after 30 years were invited for clinical examination , radiological evaluation and review using two patient-reported outcome measures . A total of seven patients ( 13.2 % ) had already undergone total knee replacement at the time of follow-up . A significant difference was observed between the operated and non-operated knee in terms of range of movement and osteoarthritis of the tibiofemoral joint , indicating a greater than fourfold relative risk of osteoarthritis at 40 years post-operatively . All patients were symptomatic as defined by the Knee Injury and Osteoarthritis Outcome Score . This study represents the longest follow-up to date and it can be concluded that meniscectomy leads to symptomatic osteoarthritis of the knee later in life , with a result ant 132-fold increase in the rate of total knee replacement 
    Output:
    
Conclusion : Results support the proposition that ACL injury predisposes knees to osteoarthritis , while ACL reconstruction surgery has a role in reducing the risk of developing degenerative changes at 10 years .
However , returning to sports activities after ligament reconstruction may exacerbate the development of arthritis