***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 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 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 / Purpose : This study sought to examine the effectiveness of a modeling video to reduce preoperative perceptions of anxiety and pain , as well as to increase postoperative self-efficacy and functional outcomes after anterior cruciate ligament reconstruction . Methods : Following baseline assessment of state anxiety , perceptions of expected pain , injury severity , and knee function ( International Knee Documentation Committee [ IKDC ] system ) , patients scheduled for surgical reconstruction of the anterior cruciate ligament were r and omly assigned to either a modeling intervention or a control group .  Psychological assessment s were repeated preoperatively for expected pain and anxiety . Actual pain was assessed preoperatively , prior to discharge , and at 2 weeks postoperatively . Rehabilitation self-efficacy was assessed prior to discharge and at 2 and 6 weeks postoperatively . IKDC functional assessment s were repeated at 6 weeks postoperatively , whereas range of motion was assessed at 2 and 6 weeks postsurgery . Results : Compared with the participants in the control condition , participants assigned to the modeling intervention reported significantly lower perceptions of expected pain preoperatively and significantly greater self-efficacy at predischarge to perform rehabilitation tasks . Those who received the modeling intervention also experienced significantly better IKDC objective functional outcome scores compared with their control counterparts . No psychological variables mediated relations between the intervention and functional outcomes . Conclusions : The data suggest that watching a modeling video may be an effective prophylactic treatment to decrease perceptions of expected pain , increase rehabilitation self-efficacy , and provide an early stimulus with respect to early function A prospect i ve , blinded , r and omised controlled trial investigated the effectiveness of quadriceps exercises  following anterior cruciate ligament reconstruction . A treatment group ( Quadriceps exercise group ) performed straight leg raises and isometric quadriceps contractions throughout the first two postoperative weeks , and a second group ( No quadriceps exercise group ) did not . A battery of outcome measures assessed subjects postoperatively at day one , two weeks , and one , three and six months . A total of 103 patients ( Quadriceps exercise n = 48 , No quadriceps exercise n = 55 ) commenced the study with 91 subjects available at final follow up ( Quadriceps exercise n = 47 , No quadriceps exercise n = 44 ) . Performance of quadriceps exercises significantly improved a number of knee flexion and extension range of motion measurements ( p = 0.01 to 0.04 ) . No significant differences were found between the two groups at any postoperative period for quadriceps lag ( p = 0.36 ) , functional hop testing ( p = 0.49 to 0.51 ) , isokinetic quadriceps strength ( p = 0.70 to 0.72 ) , the majority of numerical analogue scores ( p = 0.1 to 0.94 ) and Cincinnati scores ( p = 0.10 to 0.84 ) . Subjects performing quadriceps exercises reported significantly higher pain scores with exercise on the first postoperative day ( p = 0.02 ) . At six months postoperatively , the Quadriceps exercise subjects reported significantly more favourable Cincinnati scores for symptoms ( p = 0.005 ) and problems with sport ( p = 0.05 ) . While average knee laxity was not significantly different between treatment groups over time ( p = 0.27 to 0.94 ) , quadriceps exercise performance was associated with a significantly lower incidence of abnormal knee laxity .  Isometric quadriceps exercises and straight leg raises can be safely prescribed during the first two postoperative weeks and confer advantages for faster recovery of knee range of motion and stability . It remains to be proven whether the magnitude of differences between groups is clinical ly significant BACKGROUND AND PURPOSE Nondistally fixated ( ie , what is often referred to as " open kinetic chain " [ OKC ] ) knee extensor resistance training appears to have lost favor for some forms of rehabilitation due partly to concerns that this exercise will irritate the extensor mechanism . In this r and omized , single-blind clinical trial , nondistally fixated versus distally fixated ( ie , often called " closed kinetic chain " [ CKC ] ) leg extensor training were compared for their effects on knee pain . SUBJECTS Forty-three patients recovering from anterior cruciate ligament ( ACL ) reconstruction surgery ( 34 male , 9 female ; mean age=29 years , SD=7.9 , range=16 - 54 ) . METHODS Knee pain was measured at 2 and 6 weeks after ACL reconstruction surgery using visual analog scales in a self- assessment question naire and during maximal isometric contractions of the knee extensors . Between test sessions , subjects trained 3 times per week using either OKC or CKC resistance of their knee and hip extensors as part of their physical therapy . RESULTS No differences in knee pain were found between the treatment groups . DISCUSSION AND CONCLUSION Open kinetic chain and CKC leg extensor training in the early period after ACL reconstruction surgery do not differ in their immediate effects on anterior knee pain . Based on these findings , further studies are needed using different exercise dosages and patient groups The sensorimotor performance of the knee joint in 31 subjects who had undergone unilateral anterior cruciate ligament reconstruction at least 5 months previously was tested under three bracing conditions , 1 ) the DonJoy Legend brace , 2 ) a mechanical placebo brace , and 3 ) no brace , in r and om order . The accuracy of the subjects ’ ability to reproduce specified knee joint angles was tested as well as the isokinetic performance of their knee muscles at 60 and 180 deg/sec . The results showed that subjects with the brace or placebo brace performed similarly in reproducing the knee joint positions , but both groups performed better than the subjects without a brace . Isokinetic tests revealed no difference among the three groups in extensor and flexor peak torque production at 60 deg/sec or total work done by the extensors and flexors at 60 and 180 deg/sec . These results suggest that knee bracing can improve the static proprioception of the knee joint , but not the muscle contractile function , in subjects with anterior cruciate ligament reconstruction under isokinetic testing conditions . The finding of similar performances for joint angle reproduction in the brace and placebo brace groups suggests that the apparent improvement in proprioception with knee bracing was not due to the mechanical restraining action of the brace Thirty-seven patients who had undergone anterior cruciate ligament reconstruction were tested in a gait analysis laboratory at 2 and 6 weeks after surgery . Between test sessions , patients were r and omly assigned to a course of either closed or open kinetic chain resistance exercises ( 3 sessions per week for 4 weeks ) . Gait analysis consisted of bilateral calculations of knee joint angle , moment , and power during level walking , stair ascent , and stair descent . An analysis of variance on the effects of training group and test session indicated that the only variable to be significantly affected by the type of exercise program was the amount of knee flexion at the beginning of step-up ( P<0.05 ) . All other measures of knee angle , moment , and power ( 16 total variables ) showed no significant difference between the exercise groups . All variables measured on the injured side showed significant improvement from test 1 to test 2 ( P<0.05 ) , but the injured leg remained functionally deficient when compared with the uninjured leg . These data suggest that there are no clinical ly significant differences in the functional improvement result ing from the choice of open or closed kinetic chain exercises in the early period after this surgery A r and omised controlled trial ( 29 participants ) was used to compare a 6-week proprioceptive and balance exercise program with a 6-week strengthening program in the early phases of rehabilitation after anterior cruciate ligament ( ACL ) reconstruction . Measurements of functional activity were taken by a blinded assessor before the intervention and at the end of the 6 weeks . Results demonstrated that there were no significant differences between groups on hop testing at 6 weeks . For several items in the Cincinnati knee rating system and the patient specific functional scale however , the strengthening group improved more than the proprioceptive and balance group ( p < .05 ) . The hypothesis that proprioceptive and balance training would improve functional activity more than strengthening exercises was not supported . There was either no difference between the two forms of exercise or strength training may be more beneficial than proprioceptive and balance training in the early phase of rehabilitation after ACL reconstructive surgery The purpose of the present investigation was to evaluate physical outcome after  anterior cruciate ligament ( ACL ) reconstruction with early versus late initiation of open kinetic chain ( OKC ) exercises for the quadriceps in patients operated on either patellar tendon or hamstring grafts . Sixty-eight patients , 36 males and 32 females , with either patellar tendon graft ( 34 patients ) or hamstring graft ( 34 patients ) were enrolled in this study . All patients were r and omly allocated to either early ( the 4th postoperative week ) or late ( the 12th postoperative week ) start of OKC exercises for the quadriceps , result ing in four subgroups : patellar tendon reconstruction , early start ( P4 ) or late start ( P12 ) of OKC quadriceps exercises , hamstring tendon reconstruction , early start ( H4 ) or late start ( H12 ) of quadriceps OKC exercises . Prior to surgery and 3 , 5 and 7 months later , assessment s of range of motion ( goniometer ) , anterior knee laxity ( KT-1000 ) , postural sway ( KAT 2000 ) , thigh muscle torques ( Kin – Com dynamometer ) and anterior knee pain ( anterior knee pain score ) were evaluated . No significant group differences were found in terms of range of motion 3 , 5 and 7 months postoperatively . The H4 group showed a significantly higher mean difference of laxity over time of 1.0 mm ( CI : 0.18–1.86 ) than the P4 group ( P = 0.04 ) . Within the same type of surgery , the H4 
    Output:
    
Thirty-two soundly based rehabilitation programs , r and omized clinical trials ( RCT ’s ) and review s were included in which common physical therapy modalities ( instruction , bracing , cryotherapy , joint mobility training , muscle-strength training , gait re-education , training of neuromuscular function/balance and proprioception ) or rehabilitation programs were evaluated following ACL reconstruction with a BPTB or ST/G graft .
The results clearly indicated that an accelerated protocol without postoperative bracing , in which reduction of pain , swelling and inflammation , regaining range of motion , strength and neuromuscular control are the most important aims , has important advantages and does not lead to stability problems .
Pre clinical sessions , clear starting times and control of the rehabilitation aims with objective and subjective tests facilitate an uncomplicated rehabilitation course .