***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: STUDY DESIGN Nonr and omized prospect i ve study . OBJECTIVE To evaluate proprioception in 2 groups of patients with anterior cruciate ligament ( ACL ) deficiency who had different severity of symptoms . BACKGROUND Defective proprioception has previously been found in patients with ACL-deficient knees . It has been suggested that sensory receptors of the ACL and other knee joint ligaments contribute to proprioception and knee joint function and stability . METHODS AND MEASURES A total of 17 patients with ACL deficiency ( mean [ SD ] age , 28.8 + /- 5.6 years ; range , 22 - 39 years ) with few , if any , symptoms were compared with 20 patients with ACL deficiency ( mean [ SD ] age , 26.6 + /- 6.1 years ; range , 18 - 39 years ) having instability and episodes of giving way . The groups were compared with each other and with an age-matched reference group of 19 nonimpaired subjects . Their mean ( SD ) age was 25.6 + /- 3.7 years ( range , 20 - 37 years ) . Three tests of proprioception were used : threshold to detection of passive motion from 2 starting positions ( 20 degrees and 40 degrees of knee flexion ) toward flexion and extension , active reproduction of a 30 degrees passive angle change , and visual reproduction of a 30 degrees passive angle change . The Wilcoxon rank sum test was used for between-group comparisons . RESULTS Symptomatic patients had higher threshold to detection of passive motion in their injured side in the flexion trial from 20 degrees ( median of 1.5 degrees vs median of 0.5 degree ) and in the extension trial from 40 degrees ( median of 1.0 degree vs median of 0.5 degree ) than the asymptomatic patients . No differences were found in the other threshold tests , active or visual reproduction tests . CONCLUSIONS Patients with severe symptoms related to ACL deficiency were found to have inferior proprioceptive ability in some measurements compared with patients with a good knee function . The findings indicate that proprioceptive deficits might influence the outcome of an ACL injury treated nonoperatively Background and Purpose The purpose of this study was to determine the effect of a 6-month neuromuscular training ( NT ) program versus a traditional strength training ( ST ) program following anterior cruciate ligament ( ACL ) reconstruction . Subjects Seventy-four subjects with ACL reconstruction participated in the study . Methods The study was a r and omized , single-blinded , controlled trial . The NT and ST groups were tested preoperatively and at 3 and 6 months . The main outcome measure was the Cincinnati Knee Score . Secondary outcome measures were visual analog scales ( VASs ) for pain and function , the 36-Item Short-Form Health Survey ( SF-36 ) , hop tests , isokinetic muscle strength , proprioception , and static and dynamic balance tests . Results The NT group demonstrated significantly improved Cincinnati Knee Scores and VAS scores for global knee function compared with the ST group at the 6-month follow-up . There were no significant differences between the groups for the other outcome measures ( ie , hop , balance , proprioception , and muscle strength tests ) . Discussion and Conclusion The results of this study suggest that exercises included in the NT program should be part of the rehabilitation program following ACL reconstruction Background Female athletes participating in high-risk sports suffer anterior cruciate ligament injury at a 4- to 6-fold greater rate than do male athletes . Hypothesis Prescreened female athletes with subsequent anterior cruciate ligament injury will demonstrate decreased neuromuscular control and increased valgus joint loading , predicting anterior cruciate ligament injury risk . Study Design Cohort study ; Level of evidence , 2 . Methods There were 205 female athletes in the high-risk sports of soccer , basketball , and volleyball prospect ively measured for neuromuscular control using 3-dimensional kinematics ( joint angles ) and joint loads using kinetics ( joint moments ) during a jump-l and ing task . Analysis of variance as well as linear and logistic regression were used to isolate predictors of risk in athletes who subsequently ruptured the anterior cruciate ligament . Results Nine athletes had a confirmed anterior cruciate ligament rupture ; these 9 had significantly different knee posture and loading compared to the 196 who did not have anterior cruciate ligament rupture . Knee abduction angle ( P < . 05 ) at l and ing was 8 ° greater in anterior cruciate ligament-injured than in uninjured athletes . Anterior cruciate ligament-injured athletes had a 2.5 times greater knee abduction moment ( P < . 001 ) and 20 % higher ground reaction force ( P < . 05 ) , whereas stance time was 16 % shorter ; hence , increased motion , force , and moments occurred more quickly . Knee abduction moment predicted anterior cruciate ligament injury status with 73 % specificity and 78 % sensitivity ; dynamic valgus measures showed a predictive r2 of 0.88 . Conclusion Knee motion and knee loading during a l and ing task are predictors of anterior cruciate ligament injury risk in female athletes . Clinical Relevance Female athletes with increased dynamic valgus and high abduction loads are at increased risk of anterior cruciate ligament injury . The methods developed may be used to monitor neuromuscular control of the knee joint and may help develop simpler measures of neuromuscular control that can be used to direct female athletes to more effective , targeted interventions Background Female athletes are at significantly greater risk of anterior cruciate ligament ( ACL ) injury than male athletes in the same high-risk sports . Decreased trunk ( core ) neuromuscular control may compromise dynamic knee stability . Hypotheses ( 1 ) Increased trunk displacement after sudden force release would be associated with increased knee injury risk ; ( 2 ) coronal ( lateral ) , not sagittal , plane displacement would be the strongest predictor of knee ligament injury ; ( 3 ) logistic regression of factors related to core stability would accurately predict knee , ligament , and ACL injury risk ; and ( 4 ) the predictive value of these models would differ between genders . Study Design Cohort study ( prognosis ) ; Level of evidence , 2 . Methods In this study , 277 collegiate athletes ( 140 female and 137 male ) were prospect ively tested for trunk displacement after a sudden force release . Analysis of variance and multivariate logistic regression identified predictors of risk in athletes who sustained knee injury . Results Twenty-five athletes ( 11 female and 14 male ) sustained knee injuries over a 3-year period . Trunk displacement was greater in athletes with knee , ligament , and ACL injuries than in uninjured athletes ( P < .05 ) . Lateral displacement was the strongest predictor of ligament injury ( P = .009 ) . A logistic regression model , consisting of trunk displacements , proprioception , and history of low back pain , predicted knee ligament injury with 91 % sensitivity and 68 % specificity ( P = .001 ) . This model predicted knee , ligament , and ACL injury risk in female athletes with 84 % , 89 % , and 91 % accuracy , but only history of low back pain was a significant predictor of knee ligament injury risk in male athletes . Conclusions Factors related to core stability predicted risk of athletic knee , ligament , and ACL injuries with high sensitivity and moderate specificity in female , but not male , athletes STUDY DESIGN Prospect i ve cohort study without a control group . OBJECTIVES Firstly , to present our 5-week progressive exercise therapy program in the early stage after anterior cruciate ligament ( ACL ) injury . Secondly , to evaluate changes in knee function after completion of the program for patients with ACL injury in general and also when classified as potential copers or noncopers , and , finally , to examine potential adverse events . BACKGROUND Few studies concerning early-stage ACL rehabilitation protocol s exist . Consequently , little is known about the tolerance for , and outcomes from , short-term exercise therapy programs in the early stage after injury . METHODS One-hundred patients were included in a 5-week progressive exercise therapy program , within 3 months after injury . Knee function before and after completion of the program was evaluated from isokinetic quadriceps and hamstrings muscle strength tests , 4 single-leg hop tests , 2 different self- assessment question naires , and a global rating of knee function . A 2-way mixed-model analysis of variance was conducted to evaluate changes from pretest to posttest for the limb symmetry index for muscle strength and single-leg hop tests , and the change in scores for the patient-reported question naires . In addition , absolute values and the st and ardized response mean for muscle strength and single-leg hop tests were calculated at pretest and posttest for the injured and uninjured limb . Adverse events during the 5-week period were recorded . RESULTS The progressive 5-week exercise therapy program led to significant improvements ( P<.05 ) in knee function from pretest to posttest both for patients classified as potential copers and noncopers . St and ardized response mean values for changes in muscle strength and single-leg hop performance from pretest to posttest for the injured limb were moderate to strong ( 0.49 - 0.84 ) , indicating the observed improvements to be clinical ly relevant . Adverse events occurred in 3.9 % of the patients . CONCLUSION Short-term progressive exercise therapy programs are well tolerated and should be incorporated in early-stage ACL rehabilitation , either to improve knee function before ACL reconstruction or as a first step in further nonoperative management . LEVEL OF EVIDENCE Therapy , level 2b PURPOSE The purpose of this study was to determine , first , if there is measurable deficit in proprioception in an anterior cruciate ligament (ACL)-deficient knee , either compared to the contralateral knee or external controls ; second , if this deficit , if present , improves after ACL reconstruction ; and third , if improvement occurs , what the time course of improvement is . TYPE OF STUDY Prospect i ve cohort study . METHODS Patients undergoing ACL reconstruction at the University of Chicago , demonstrating a full and painless range of motion and no other knee ligament injury or history of previous knee surgery , were eligible . Twenty-six patients , with an average age of 25 years ( range , 16 to 48 ) were enrolled . Average time from injury to reconstruction was 8 weeks . The patients ' contralateral knee served as an internal control , and 26 age-matched and gender-matched healthy volunteers were enrolled as an external control group . ACL reconstructions were performed using a single-incision technique with either bone-patellar tendon-bone or quadrupled hamstring autograft . They were allowed immediate weightbearing as tolerated and participated in a st and ardized rehabilitation program , with the goal of returning to sport at approximately 6 months . Proprioception testing was carried out using an electrogoniometer , in a seated position . Joint position sense ( JPS ) and threshold to detection of passive motion ( TDPM ) were measured preoperatively and at 3 and 6 weeks and 3 and 6 months postoperatively . RESULTS Mean KT-2000 values 6 months postoperatively were 1.38 mm ( + /-2 ) . Modified Lysholm score improved significantly ( P < .01 ) . Calculated r values were 0.65 for JPS and 0.96 for TDPM . No significant differences in postoperative proprioception were found between hamstring and patellar tendon grafts or among patients with meniscus injury , meniscus repair , or chondral injury . Preoperatively , the mean TDPM in both the injured and contralateral knees was significantly higher ( worse ) than in the external control knees ( P = .008 ; P = .016 ) . Evaluation of changes in proprioception from preoperative to 6 months postoperative showed significant improvement in both injured and contralateral knees ( P = .04 ; P = .01 ) . At 6-month follow-up , there was no significant difference from controls . CONCLUSIONS TDPM was a more reliable method than JPS for testing proprioception before and after ACL reconstruction in this study . Bilateral deficits in knee joint proprioception ( TDPM ) were documented after unilateral ACL injury .  Reconstruction of a mechanical restraint ( ACL graft ) was believed to have a significantly positive impact on early and progressive improvement in proprioception STUDY DESIGN Prospect i ve r and omized longitudinal clinical trial with matched controls . OBJECTIVES To investigate the long-term effect of training on postural control and extremity function after an acute anterior cruciate ligament ( ACL ) injury . BACKGROUND ACL injuries may cause severe problems with recurrent giving way of the knee and reduced functional capacity . The effect of an acute ACL injury and the effect of various training programs on postural control , as well as the relation between postural control and extremity function after such an injury , have not been studied longitudinally . METHODS Sixty-three consecutive patients , 35 men and 28 women ( median age 24 years , quartiles 19 - 33 years ) , with an acute nonoperated ACL injury , r and omized to neuromuscular supervised or self-monitored training  , were examined with  stabilometry ( amplitude and average speed of center of pressure movements ) and a one-leg hop test  for distance after 6 weeks ( stabilometry only ) , and after 3 , 12 , and 36 months , and were compared to a control group . RESULTS Regardless of treatment , center of pressure amplitude was persistently higher in both the injured and uninjured legs during the 3-year follow-up , but average speed was less affected or unaffected compared to the control group . The one-leg hop had normalized in the neuromuscular group at the 12-month follow-up , but was shorter in both legs throughout the 3-year period in the self-monitored group . The median value ( quartiles ) for injured 
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However , the within-group difference was found to be significant during eyes closed condition , with injured leg displaying larger sway .
Conclusions The present review indicates that postural control is impaired in both legs , especially injured leg .
The result of within-group difference in eyes open condition confirms bilateral deficit of postural control .
However , the within-group difference during eyes closed condition indicates again that ACL injury affects the injured leg more than the uninjured leg .