***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: OBJECTIVE To determine the emotional and cognitive impact of injury and surgery on physical recovery in injured athletes . DESIGN A prospect i ve longitudinal study comparing the psychosocial and physical recovery of competitive and recreational athletes . SETTING Tertiary-care sports medicine center . PARTICIPANTS Twenty-seven athletes ( 15 men and 12 women ) who required anterior cruciate ligament ( ACL ) reconstruction surgery .  INTERVENTIONS A repeated- measures design used to compare the psychosocial and physical changes for 6 months after ACL surgery . MAIN OUTCOME MEASURES Emotional ( mood ) and cognitive ( coping ) functions and physical recovery ( range of motion , physician-rated level of recovery , and physician permission to return to sport ) . RESULTS There was a significant time-effect difference in mood , with a greater mood disturbance and recovery rate for competitive athletes than recreational athletes . Differences in mood and pain coping were significant at 2 weeks and 2 months after surgery . CONCLUSION Athletes experience significant mood changes throughout rehabilitation , which may hinder rehabilitation early in the process . Longer-term rehabilitation was not impacted by mood or pain coping . Future studies might focus on examining the process over a longer time period ( 1 - 2 years after surgery ) . Physicians should be aware of these findings and appropriately counsel and motivate athletes toward more favorable positive psychological and physical outcomes In this prospect i ve study we investigated 70 patients with chronic anterior instability who underwent anterior cruciate ligament reconstruction with a Dacron pros thesis . Fifty-five ( 79 % ) patients could be followed up at a mean of 9 years . Within the follow-up time , 44 % ( 29 of 66 ) of the prostheses were diagnosed as ruptured ; the annual rupture frequency was 5 % . Second recon structions were performed for 20 patients ( 29 % ) , 5 patients had third reconstructions , and 9 patients wanted no further surgical treatment . Fifty-two patients ( 74 % of the original group ) underwent  radiographic examination .  Eighty-three percent ( 43 ) of these pa tients had radiographic changes in the operated knee , and 40 % ( 21 of 52 ) had joint space reduction up to 50 % . The rate of radiographically detected osteoarthi tis was increased 10 times compared with the normal knee . Patients with medial instability and patients older than 30 years at the initial operation had more severe osteoarthritic changes . Based on the functional results of the patients with a ligament in place after 9 years , only 14 % ( 10 ) of the original group had acceptable stability and knee function Purpose The purpose of this prospect i ve study was to describe the variability in leg muscle power and hop performance up to 2 years among patients following ACL reconstruction and specifically to illustrate the effects of various criteria for an acceptable level of muscle function . Methods Eighty-two patients ( 56 men and 26 women ) with a mean age of 28 years , who underwent ACL reconstruction using either hamstring tendons ( n = 46 ) or a patellar tendon ( n = 36 ) , were assessed pre-operatively and 3 , 6 , 12 and 24 months  post-surgery  with a battery of three lower extremity muscle power tests and a battery of three hop tests . Results Leg symmetry index ( LSI ) values at group level ranged between 73 and 100 % at all follow-ups . When the tests were evaluated individually , patients reached an average LSI of ≥90 % at 24 months . The success rate at 24 months for the muscle power test battery , that is , patients with an LSI of ≥90 % in all three tests , was 48 and 44 % for the hop test battery . The success rate at 24 months for both test batteries on all six muscle function tests was 22 % . The criterion of an LSI of ≥80 % result ed in 53 % of the patients having an acceptable level on all six tests , while with a criterion of an LSI of ≥100 % , none of the patients reached an acceptable level . Conclusion At group level and in single muscle function tests , the muscle function outcome 1 and 2 years after ACL reconstruction is satisfactory in the present study and on a par with the results presented in the literature . However , when using more dem and ing criteria for a successful muscle function outcome , using batteries of tests or increasing the acceptable LSI level from ≥90 % to ≥95 % or ≥100 % , the results are considered to be poor . It is suggested that this should be taken into consideration when presenting results after ACL rehabilitation , deciding on the criteria for a safe return to sports , or design ing rehabilitation programmes after ACL reconstruction . Level of evidence Prognostic prospect i ve cohort study , Level 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 Background and Purpose Although various hop tests have been proposed as performance-based outcome measures following anterior cruciate ligament ( ACL ) reconstruction , limited reports of their measurement properties exist . The purpose of this study was to investigate the reliability and longitudinal validity of data obtained from hop tests during rehabilitation after ACL reconstruction . Subjects Forty-two patients , 15 to 45 years of age , who had undergone ACL reconstruction participated in the study . Methods and Measures The study design was prospect i ve and observational with repeated measures . The subjects performed a series of 4 hop tests on 3 separate occasions within the 16th week following surgery and on a fourth occasion 6 weeks later . The tests were a  single hop for distance  , a 6-m timed hop , a triple hop for distance  , and  crossover hops for distance .  Performance on the ACL-reconstructed limb was expressed as a percentage of the performance on the nonoperative limb , termed the “ limb symmetry index . ” Subjects also completed the Lower Extremity Functional Scale and a global rating of change question naire . Results Intraclass correlation coefficients for limb symmetry index values ranged from .82 to .93 . St and ard errors of measurement were 3.04 % to 5.59 % . Minimal detectable changes , at the 90 % confidence level , were 7.05 % to 12.96 % . Changes in hop test scores on the operative limb were statistically greater than changes on the nonoperative limb . Pearson correlations ( r ) between change in hop performances and self-reported measures ranged from .26 to .58 . Discussion and Conclusion The results show that the described series of hop tests provide a reliable and valid performance-based outcome measure for patients undergoing rehabilitation following ACL reconstruction . These findings support the use and facilitate the interpretation of hop tests for research and clinical practice Background : Little is known about the return to sports after  anterior cruciate ligament reconstruction  and whether sex differences exist regarding the level and timing at which athletes return . Hypotheses : Compared to school-aged girls , boys return to full sports earlier and at a higher frequency after surgery ( 1 ) . Athletes who return to sports earlier will not have a higher incidence of subsequent injury to either knee after surgery ( 2 ) . Study Design : Cohort . Methods : The patient population comprised 413 consecutive school-aged athletes who were injured while competing in basketball or soccer . Patients were enrolled prospect ively , and activity levels were obtained through follow-up visits , surveys , phone calls , and e-mail . Results : Follow-up was obtained for 402 patients ( basketball : 58 boys , 242 girls ; soccer : 25 boys , 77 girls ) . Eighty-seven percent of girls and boys returned to high school basketball after surgery : the mean time to return to full participation in basketball was 5.2 ± 2.1 months for girls and 5.3 ± 2.2 months for boys ( P = .92 ) . Similarly , 93 % of girls and 80 % of boys returned to compete in high school soccer after surgery ( P = .13 ) ; the mean time to return to full participation in soccer was 5.1 ± 1.9 months for girls and 5.1 ± 2.0 for boys ( P = 1.00 ) . About 20 % of athletes went on to compete in their sport in college . The time of return to sports was not a statistically significant factor for the incidence of subsequent anterior cruciate ligament injury . Conclusion : Of 402 athletes competing in basketball and soccer , women and men returned at the same rate and same level of sport after surgery . Athletes who returned to sports at earlier times after surgery did not have a higher incidence of subsequent anterior cruciate ligament injury than patients who returned at later times A prospect i ve comparative study was conducted involving 62 patients to determine the effects and limits of accelerated rehabilitation on clinical outcome . The study focused on whether aggressive rehabilitation after anterior cruciate ligament reconstruction with the doubled semitendinosus and gracilis tendon autograft results in stretching the graft . Thirty patients had postoperative rehabilitation according to the current conservative protocol , and 32 patients had rehabilitation using an accelerated regime .  Each patient was evaluated subjectively and objective ly 36 months or more after surgery . Concerning the side-to-side difference in the anterior laxity , 87 % of the patients in the conservative rehabilitation group had 3 mm or less and 80 % of the patients in the accelerated rehabilitation group had the same acceptable laxity . There was no significant difference between the two groups . Muscle torque was restored significantly earlier in the patients in the accelerated rehabilitation group than in the patients in the conservative rehabilitation group . Nine months after surgery , however , there were no significant differences in the torque between the two groups . Accelerated rehabilitation significantly increased the incidence of knee effusion during rehabilitation . This study showed that acceleration of postoperative rehabilitation could rapidly restore muscle strength without significantly compromising graft stability in anterior cruciate ligament reconstruction with the doubled hamstring tendon autograft . However , this study also showed that acceleration significantly increases the incidence of synovitis . Acceleration of postoperative rehabilitation has advantages and disadvantages for clinical outcome after anterior cruciate ligament reconstruction Background : Although previous studies suggested that female patients are predisposed to increase graft laxity compared with male patients after  single-bundle anterior cruciate ligament reconstruction using autogenous hamstring tendons , there have been no studies specifically examining gender-based differences in outcome after anatomic double-bundle anterior cruciate ligament reconstruction with hamstring tendon autografts . Hypotheses : ( 1 ) Female patients have significantly smaller hamstring graft diameters than do men for anatomic double-bundle anterior cruciate ligament reconstruction surgery ; ( 2 ) female patients will have increased graft laxity compared with male patients after  anatomic double-bundle anterior cruciate ligament reconstruction using autogenous hamstring tendons . Study Design : Cohort study ; Level of evidence , 2 . Methods : The consecutive 174 patients who underwent anatomic double-bundle anterior cruciate ligament reconstruction using autogenous hamstring tendons were enrolled . Of these patients , 49 women and 73 men were prospect ively evaluated 2 years after surgery . Results : The diameters for anteromedial and posterolateral grafts in the female group were significantly smaller than those in the male group . On Lachman testing , 98 % of the female group and 97 % of the male group were rated as negative . Regarding the pivot-shift test , 80 % of the female group and 85 % of the male group were rated as negative . No significant differences were found between the female and male groups in these tests . The average side-to-side differences in the KT-2000 kne 
    Output:
    
Other outcomes were comparable between sexes , including anterior drawer test , Lachman test , pivot-shift test , timed single-legged hop test , single-legged hop test , quadriceps testing , hamstring testing , extension loss , flexion loss , development of cyclops lesion , and International Knee Documentation Committee ( IKDC ) knee examination score .
Females and males were equally likely to develop anterior knee pain and osteoarthritis after ACL reconstruction .
The graft rupture and graft failure rates did not differ significantly between sexes .
Conclusion : There were comparable or inferior results for females compared with males in all outcomes analyzed .
No statistically significant sex difference was identified in most of the objective parameters .
However , subjective and functional outcomes , including Lysholm score , Tegner activity scale , and ability to return to sports , have been shown to be poorer in females