Relationship of the menstrual cycle phase to anterior cruciate ligament injuries in teenaged female athletes A prospective cohort study of anterior cruciate ligament injuries in elite Norwegian team handball. Incidence of Contralateral and Ipsilateral Anterior Cruciate Ligament (ACL) Injury After Primary ACL Reconstruction and Return to Sport The Menstrual Cycle, Sex Hormones, and Anterior Cruciate Ligament Injury. Risk Factors for Anterior Cruciate Ligament Injury The Association of the Menstrual Cycle with the Laxity of the Anterior Cruciate Ligament in Adolescent Female Athletes The Effects of Generalized Joint Laxity on Risk of Anterior Cruciate Ligament Injury in Young Female Athletes A Prospective Evaluation of the Landing Error Scoring System (LESS) as a Screening Tool for Anterior Cruciate Ligament Injury Risk A Randomized Controlled Trial to Prevent Noncontact Anterior Cruciate Ligament Injury in Female Collegiate Soccer Players Effect of the Oral Contraceptive Pill on Ligamentous Laxity Anterior Cruciate Ligament Injury Risk Factors Associated with Noncontact Injury of the Anterior Cruciate Ligament Predisposing risk factors for non-contact ACL injuries in military subjects Deficits in Neuromuscular Control of the Trunk Predict Knee Injury Risk Identification of Athletes at Future Risk of Anterior Cruciate Ligament Ruptures by Neuromuscular Screening Incidence and risk factors for graft rupture and contralateral rupture after anterior cruciate ligament reconstruction. Rehabilitation following acute anterior cruciate ligament injuries--a 12-month follow-up of a randomized clinical trial.
Introduction Anterior cruciate ligament ( ACL ) injuries are more common among female athletes compared to male athletes . Several studies have been reported to explain the gender difference in ACL injury rates and several risk factors underlying gender disparity are believed to exist . Hormonal effects are considered to be one of the etiological factors for female non-contact ACL injuries . The objectives of this study were to determine if ACL injuries occurred r and omly or correlated with a specific phase of the female menstrual cycle in teenaged female athletes and then to determine if pre-menstrual and menstrual dysfunctions influenced these ACL injuries . Material s and methods Eighteen of 37 consecutive female athletes , with ACL injuries , met the study criteria : teenage , with regular menstrual cycle , and non-contact injury . The menstrual history , athletic activity , and injury history were collected . Results Seventy-two percent of the subjects had premenstrual symptoms and 83 % had  menstrual symptoms . The subjective activity level at the follicular phase was significantly lowest between the phases . A significant statistical association was found between the phase of the menstrual cycle and ACL injuries ( P = 0.0002 ) . There were more injuries in the ovulatory phase than expected , and fewer injuries occurred in the other phases . Conclusion The results showed a significant increase in non-contact ACL injuries in teenage female athletes during the ovulatory phase of the menstrual cycle and the subjective activity level and the premenstrual and menstrual symptoms might not affect the likelihood of the injuries . These findings suggest that sex hormones might play a role in the incidence of female non-contact ACL injuries The purpose of this study was to examine gender differences in the incidence of  anterior cruciate ligament ( ACL ) injuries in a population of high-level team h and ball players . We also wanted to examine injury mechanisms and possible risk factors for ACL injuries , including menstrual status . The study was done prospect ively during the 1993 - 94 , 1994 - 95 , and 1995 - 96 seasons . We found 28 ACL injuries , 23 among women ( incidence : 0.31 + /- 0.06 injuries per 1000 player hours ) and 5 among men ( 0.06 + /- 0.03 inj./1000 h ; P < 0.001 vs women ; risk ratio : 5.0 ) . Of the 28 injuries , 24 occurred during competition ( 0.91 + /- 0.19 inj./1000 h ; women : 1.60 + /- 0.35 inj./1000 h ; men : 0.23 + /- 0.13 inj./1000 h ; P < 0.001 vs. women ; risk ratio : 7.0 ) and 4 during training ( 0.03 + /- 0.02 inj./1000 h ; P < 0.001 vs. competition ; risk ratio : 29.9 ) . Nearly all the injuries ( n = 25 ) occurred in non-contact situations when the players performed high-speed plant- and -cut movements which they were well accustomed to . A reliable menstrual history could be obtained in 17 of the 23 cases among females . Five of the injuries occurred in the menstrual phase , 2 in the follicular phase , 1 in the early luteal phase and 9 in the late luteal phase ( chi-square3 d.f . = 13.2 ; P < 0.01 ) . The results suggest that there may be an increased risk of ACL injury during the week prior to or after the start of the menstrual period Objective Incidence rate ( IR ) of an ipsilateral or contralateral injury after  anterior cruciate ligament reconstruction ( ACLR )  is unknown . The hypotheses were that the IR of anterior cruciate ligament ( ACL ) injury after ACLR would be greater than the IR in an uninjured cohort of athletes and would be greater in female athletes after ACLR than male athletes . Design Prospect i ve case – control study . Setting Regional sports community . Participants Sixty-three subjects who had ACLR and were ready to return to sport ( RTS ) and 39 control subjects . Independent Variables Second ACL injury and sex . Main Outcome Measures Second ACL injury and athletic exposure ( AE ) was tracked for 12 months after RTS . Sixteen subjects after ACLR and 1 control subject suffered a second ACL injury . Between- and within-group comparisons of second ACL injury rates ( per 1000 AEs ) were conducted . Results The IR of ACL injury after ACLR ( 1.82/1000 AE ) was 15 times greater [ risk ratio ( RR ) = 15.24 ; P = 0.0002 ) than that of control subjects ( 0.12/1000AE ) . Female ACLR athletes demonstrated 16 times greater rate of injury ( RR = 16.02 ; P = 0.0002 ) than female control subjects . Female athletes were 4 ( RR = 3.65 ; P = 0.05 ) times more likely to suffer a second ACL injury and 6 times ( RR = 6.21 ; P = 0.04 ) more likely to suffer a contralateral injury than male athletes . Conclusions An increased rate of second ACL injury after ACLR exists in athletes when compared with a healthy population . Female athletes suffer contralateral ACL injuries at a higher rate than male athletes and seem to suffer contralateral ACL injuries more frequently than graft re-tears . The identification of a high-risk group within a population of ACLR athletes is a critical step to improve outcome after ACLR and RTS OBJECTIVE : To determine if anterior cruciate ligament ( ACL ) injuries in female athletes occur r and omly or correlate with a specific phase of the menstrual cycle . DESIGN AND SETTING : Female athletes who sustained ACL injuries reported the days of their menstrual cycles and provided saliva sample s for sex-hormone determination . Salivary sex-hormone profiles were assessed to confirm the self-reported menstrual histories . SUBJECTS : A total of 38 female athletes ( 20 college , 15 high school , 1 middle school , 2 recreational ) with recent ACL injuries participated in the study over a 3-year period . MEASUREMENTS : Athletes with recent ACL injuries completed a question naire defining the injury , the last menstrual cycle , prior knee injury , school , and type of birth control used ( if any ) . Each subject provided a 30-cc saliva sample within 72 hours of injury . Saliva sample s were placed into sealed containers and frozen at -20 degrees C. We obtained 13 additional control sample s from uninjured females to test the correlation between saliva and serum sex-hormone levels . Progesterone and estrogen were assayed by radioimmunoassay . Physical examination , magnetic resonance imaging , or surgery confirmed the injury in all subjects . RESULTS : The correlations between saliva and serum estrogen and progesterone were 0.73 ( alpha = .01 ) and 0.72 ( alpha = .01 ) , respectively . Ten of 27 athletes who reported their cycle day at time of injury sustained an ACL injury immediately before or 1 to 2 days after the onset of menses . We rejected the null hypothesis that such high frequency was due to r and om chance . CONCLUSIONS : A significantly greater number of ACL injuries occurred on days 1 and 2 of the menstrual cycle . Salivary sex-hormone levels correlated with the reported cycle day Context : Injuries to the anterior cruciate ligament ( ACL ) of the knee are immediately debilitating and can cause long-term consequences , including the early onset of osteoarthritis . It is important to have a comprehensive underst and ing of all possible risk factors for ACL injury to identify individuals who are at risk for future injuries and to provide an appropriate level of counseling and programs for prevention . Objective : This review , part 1 of a 2-part series , highlights what is known and still unknown regarding anatomic and neuromuscular risk factors for injury to the ACL from the current peer- review ed literature . Data Sources : Studies were identified from MEDLINE ( 1951–March 2011 ) using the MeSH terms anterior cruciate ligament , knee injury , and risk factors . The bibliographies of relevant articles and review s were cross-referenced to complete the search . Study Selection : Prognostic studies that utilized the case-control and prospect i ve cohort study design s to evaluate risk factors for ACL injury were included in this review . Results : A total of 50 case-control and prospect i ve cohort articles were included in the review , and 30 of these studies focused on neuromuscular and anatomic risk factors . Conclusions : Several anatomic and neuromuscular risk factors are associated with increased risk of suffering ACL injury — such as female sex and specific measures of bony geometry of the knee joint , including decreased intercondylar femoral notch size , decreased depth of concavity of the medial tibial plateau , increased slope of the tibial plateaus , and increased anterior-posterior knee laxity . These risk factors most likely act in combination to influence the risk of ACL injury ; however , multivariate risk models that consider all the aforementioned risk factors in combination have not been established to explore this interaction Objective To identify a significant change in the laxity of the anterior cruciate ligament ( ACL ) in the competitive adolescent female athlete throughout the different phases of the menstrual cycle . Design Prospect i ve , single-blinded 8-week study set during a winter sports season . Setting Suburban Ohio Division I high school . Participants 26 members of gymnastics , soccer , track , tennis , and basketball teams . All participants were screened for normal menstrual cycles ( 26–30 days , menses 4–7 days long ) . Main Outcome Measures  KT-1000 arthrometer  was used to measure laxity by performing repeated measures throughout an 8-week period . Measurements were taken before the athletes ' workouts . The athlete charted the menstrual periods on a monthly calendar . The measurements were then grouped into the three phases of the menstrual cycle ( follicular , ovulatory , and luteal ) and averaged . Results Right knee laxity measured 4.98 mm follicular phase , 5.24 mm ovulatory , and 5.09 mm luteal . Left knee laxity measured 4.51 mm follicular , 4.43 mm ovulatory , and 4.62 mm luteal . There was no statistical difference among the three phases in the left ( p = 0.9 ) and right ( p = 0.7977 ) . Additionally , left ACL laxity was significantly less in all three phases . We found no statistically significant variability in laxity among the five sports sample d ( p > 0.63 to 0.10 ) and different ages ( p = 0.404 ) Conclusions We found an insignificant change in ACL laxity from follicular to luteal phases of the menstrual cycle . This indicates that no single phase of the menstrual cycle clinical ly affects the ACL more than the next . Although the presence of sex hormones — particularly estrogen — may indeed predispose females to higher ACL injury rates , we did not find any evidence that hormonal level changes equate with significant ACL laxity changes . We conclude that the menstrual cycle does not significantly affect ACL laxity in the competitive adolescent female athlete Background Women who participate in high-risk sports suffer anterior cruciate ligament injury at a 4- to 6-fold greater rate than men . Purpose To prospect ively determine if female athletes with decreased passive knee joint restraint ( greater joint laxity ) and greater side-to-side differences in knee laxity would be at increased risk of anterior cruciate ligament injury . Study Design Case control study ; Level of evidence , 3 . Methods From 1558 female soccer and basketball players who were prospect ively screened , 19 went on to tear their anterior cruciate ligaments . Four height- and mass-matched control subjects were selected from the uninjured screened athletes for comparison with each of the 19 injured subjects , making a total of 95 subjects ( 19 injured ; 76 uninjured ) . Generalized joint-laxity tests and anterior-posterior tibiofemoral translation were quantified using the CompuKT knee arthrometer . A multivariable logistic regression model was constructed to determine predictors of anterior cruciate ligament injury status from recorded laxity measures . Results A multivariable logistic regression model ( chi-square = 18.6 ; P = .002 ) used the independent variables laxity measures of knee hyperextension ( P = .02 ) , wrist and thumb to forearm opposition ( P = .80 ) , fifth-finger hyperextension > 90 ° ( P = .71 ) , side-to-side differences in anterior-posterior tibiofemoral translation ( P = .002 ) , and prior knee injury ( P = .22 ) to predict anterior cruciate ligament-injury status . The vali date d C statistic , or vali date d area under the receiver operating characteristic curve , was 0.72 . For every 1.3-mm increase in side-to-side differences in anterior-posterior knee displacement , the odds of anterior cruciate ligament – injured status increased 4-fold ( 95 % confidence interval , 1.68–9.69 ) . A positive measure of knee hyperextension increased the odds of anterior cruciate ligament-injured status 5-fold ( 95 % confidence interval , 1.24–18.44 ) . Conclusion The current results indicate that increased knee-laxity measures may contribute to increased risk of anterior cruciate ligament injury . The methods to quantify knee joint laxity in this report may be used in conjunction with measures of neuromuscular control of the knee joint to identify high-risk female athletes with high accuracy . Once high-risk female athletes are identified , they may be targeted to the appropriate interventions to reduce injury risk Background : Anterior cruciate ligament ( ACL ) injuries are immediately disabling , costly , take a significant amount of time to rehabilitate , and are associated with an increased risk of developing posttraumatic osteoarthritis of the knee . Specific multiplanar movement patterns of the lower extremity , such as those associated with the drop vertical jump ( DVJ ) test , have been shown to be associated with an increased risk of suffering noncontact ACL injuries . The  L and ing Error Scoring System ( LESS )  has been developed as a tool that can be applied to identify individuals who display at-risk movement patterns during the DVJ . Hypothesis : An increase in LESS score  is associated with an increased risk of noncontact ACL injury . Study Design : Case-control study ; Level of evidence , 3 . Methods : Over a 3-year interval , 5047 high school and college participants performed preseason DVJ tests that were recorded using commercial video cameras .  All participants were followed for ACL injury during their sports season , and video data from injured participants and matched controls were then assessed with the LESS . Conditional logistic regression analysis was used to examine the association between  LESS score and ACL injury risk in all participants as well as subgroups of female , male , high school , and college participants . Results : There was no relationship between the risk of suffering ACL injury and LESS score  whether measured as a continuous or a categorical variable . This was the case for all participants combined ( odds ratio , 1.04 per unit increase in LESS score ; 95 % confidence interval , 0.80 - 1.35 ) as well as within each subgroup ( odds ratio range , 0.99 - 1.14 ) . Conclusion : The LESS did not predict ACL injury in our cohort of high school and college athletes Background Neuromuscular and proprioceptive training programs can decrease noncontact anterior cruciate ligament injuries ; however , they may be difficult to implement within an entire team or the community at large . Hypothesis A simple on-field alternative warm-up program can reduce noncontact ACL injuries . Study Design R and omized controlled trial ( clustered ) ; Level of evidence , 1 . Methods Participating National Collegiate Athletic Association Division I women 's soccer teams were assigned r and omly to intervention or control groups . Intervention teams were asked to perform the program 3 times per week during the fall 2002 season . All teams reported athletes ’ participation in games and practice s and any knee injuries . Injury rates were calculated based on athlete exposures , expressed as rate per 1000 athlete exposures . A z statistic was used for rate ratio comparisons . Results Sixty-one teams with 1435 athletes completed the study ( 852 control athletes ; 583 intervention ) . The overall anterior cruciate ligament injury rate among intervention athletes was 1.7 times less than in control athletes ( 0.199 vs 0.340 ; P = .198 ; 41 % decrease ) . Noncontact anterior cruciate ligament injury rate among intervention athletes was 3.3 times less than in control athletes ( 0.057 vs 0.189 ; P = .066 ; 70 % decrease ) . No anterior cruciate ligament injuries occurred among intervention athletes during practice versus 6 among control athletes ( P = .014 ) . Game-related noncontact anterior cruciate ligament injury rates in intervention athletes were reduced by more than half ( 0.233 vs 0.564 ; P = .218 ) . Intervention athletes with a history of anterior cruciate ligament injury were significantly less likely to suffer another anterior cruciate ligament injury compared with control athletes with a similar history ( P = .046 for noncontact injuries ) . Conclusion This program , which focuses on neuromuscular control , appears to reduce the risk of anterior cruciate ligament injuries in collegiate female soccer players , especially those with a history of anterior cruciate ligament injury Objective : Women are 4 to 8 times more likely to sustain a serious  knee  injury than their male counterparts . Previous studies have found that female sex steroids affect ligamentous tissue properties . The hypothesis is that there exists a difference in ligamentous laxity between  oral contraceptive pill ( OCP ) users and nonusers . Design : Blinded , single-factor , posttest-only control group design . Setting : McGill University Sport Medicine Clinic , Montreal , Que-bec , Canada . Participants : One hundred twenty-seven female McGill University varsity athletes . Interventions : Participants filled out a screening question naire and underwent KT-1000 measurements by 1 blinded examiner . Exclusion criteria related to underlying knee pathology , and hormonal factors were identified with the question naire . Main Outcome Measurements : Independent sample , 2-tailed t tests were performed on the nondominant knee data of the OCP users and nonusers . Results : Mean anterior translations at 67 N were 3.00 ± 1.04 mm for the OCP users and 3.86 ± 1.72 mm for the nonusers ( P = 0.011 ) ; at 89 N , 3.98 ± 1.13 mm vs. 4.83 ± 1.82 mm , respectively ( P = 0.018 ) . Mean anterior translations at 67 N were 2.95 ± 0.93 mm for the non-menstruating OCP users and 3.86 ± 1.72 mm for the nonusers ( P = 0.008 ) ; at 89 N , 3.88 ± 1.06 mm vs. 4.83 ± 1.82 mm , respectively ( P = 0.011 ) . Conclusions : Oral contraceptive pill use yielded statistically significant decreases in anterior translation of the tibia as compared with nonusers . The OCP may have a role to play in the prevention of ACL injuries by prophylactically targeting 1 of the variables responsible for the increased ACL injury rates in women Objectives : The objective of this study was to analyze whether it is more frequent the presence of a decreased range of motion in the hips of recreational athletes with primary injury of the anterior cruciate ligament ( ACL ) than in a control group of volunteers without knee pathology . Methods : We included prospect ively recreational athletes between 18 and 40 years with an acute ACL injury between January 2011 and January 2013 . They were compared with a control group of volunteers recreational athletes without lower limb pathology and in the same range of age . The internal and external rotations passively prior to the point at which the pelvis movement contributes were observed . The results were statistically analyzed using t test for related sample s to the hips of patients with ACL injury and t test for independent variables for comparison with the control group . Results : 48 patients with ACL injury and 53 healthy volunteers were evaluated . The ACL group was composed of 32 males and 16 females with an average age of 29.3 years . In the control group 26 males and 27 females were studied with a mean age of 26.6 years . Internal ( IR ) and external ( ER ) rotation in the LCA group was 22,9º and 55,5º respectively in the ipsilateral hip and 27,9º and 57,7º in the contralateral . In the control group a 35,9º of IR and 55,2º of ER was observed . The analysis showed an association between ACL injury and hypomotility of the hip further expense of a decrease in internal rotation . The analysis showed an association between ACL injury and hypomotility of the hip at the expense to a greater decrease in internal rotation . Conclusion : We found a statistically significant difference in the mobility of the hips in patients with ACL injury predominantly due to internal rotation , pattern that allows us to interpret this injury not only as an intrinsic etiology of the knee but also of the adjacent joints . We consider very importance to incorporate prevention activities and screening of risk factors regarding to at least high performance athletes Background : The causes of noncontact anterior cruciate ligament injury remain an enigma . Purpose : To prospect ively evaluate risk factors for noncontact anterior cruciate ligament injuries in a large population of young athletic people . Study Design : Prospect i ve cohort study . Methods : In 1995 , 1198 new United States Military Academy cadets underwent detailed testing and many parameters were documented . During their 4-year tenure , all anterior cruciate ligament injuries that occurred were identified . Statistical analyses were used to identify the factors that may have predisposed the cadets to noncontact anterior cruciate ligament injuries . Results : Among the 895 cadets who completed the entire 4-year study , there were 24 noncontact anterior cruciate ligament tears ( 16 in men , 8 in women ) . Significant risk factors included small femoral notch width , generalized joint laxity , and , in women , higher than normal body mass index and KT-2000 arthrometer values that were 1 st and ard deviation or more above the mean . The presence of more than one of these risk factors greatly increased the relative risk of injury . All female cadets who had some combination of risk factors sustained noncontact anterior cruciate ligament injuries , indicating that some combinations of factors are especially perilous to the female knee . Conclusion : Several risk factors may predispose young athletes to noncontact anterior cruciate ligament injury Purpose The goal of this study was to document the incidence of anterior cruciate ligament ( ACL ) tears and possible risk factors for these injuries in a large population of young , athletic subjects . Methods The authors retrospectively review ed the US Naval Academy ’s data base of midshipmen admitted in 1999 and 2000 ( n = 2,345 ) and prospect ively followed until graduation 4 years later or disenrollment . Excluded were 658 who had a history of preadmission ACL injury or surgery , those without initial radiographs or documented baseline height and weight , or those who had documented contact ACL injuries . Therefore , 1,687 subjects comprised the study group .  St and ard radiographic measurements , including condylar width , notch width , and femoral notch width index ( notch width divided by condyle width ) , were obtained for all subjects . Statistical analyses were used to determine differences between injured and uninjured subjects . Results The overall incidence of non-contact ACL injury was 2.9 % ( 37 men , 12 women ) . The average BMI was 25.6 and 24.4 kg/m2 for the injured and uninjured groups , respectively ( P < 0.05 ) . Although femoral notch width alone was not associated with non-contact ACL injuries , subjects with higher than average BMI in combination with narrow notch width were at significant risk for ACL injury ( P = 0.021 ) . Conclusions Elevated BMI combined with narrow notch width may predispose young athletes to non-contact ACL injury . Level of evidence Retrospective comparative study , Level III 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 Background A high percentage of female athletes who sustain an anterior cruciate ligament ( ACL ) rupture suffer serious long-term consequences such as osteoarthritis and disability . Thus , identification of risk factors has high clinical relevance in the prevention of ACL rupture . Hypothesis Noninjured athletes with low knee flexor electromyography ( EMG ) preactivity and high knee extensor EMG preactivity during sidecutting are at increased risk of future ACL rupture . Study Design Cohort study ( prognosis ) ; Level of evidence , 2 . Methods Fifty-five elite female athletes ( team h and ball and soccer ) aged 24 ± 5 years with no history of ACL injury  were tested for EMG preactivity of vastus lateralis and medialis , rectus femoris , semitendinosus , and biceps femoris during a st and ardized side-cutting maneuver . The incidence of ACL ruptures was registered in the following 2 match seasons . Results During the subsequent 2 match seasons , 5 athletes sustained a confirmed noncontact ACL rupture . Before injury , all 5 players displayed a neuromuscular pattern that differed from the noninjured players , characterized by reduced EMG preactivity for the semitendinosus ( ST ) and elevated EMG preactivity for the vastus lateralis ( VL ) ( P < .01 ) . On the basis of these findings , a high-risk zone was defined as one st and ard deviation above the mean VL-ST difference . In our population , 5 of 10 subjects with a VL-ST difference in this zone sustained an ACL injury during the study period . Conclusion In the present study , currently noninjured female athletes with reduced EMG preactivity of the ST and increased EMG preactivity of the VL during side cutting were at increased risk of future noncontact ACL rupture . Our data indicate that a high-risk zone can be used to identify noninjured players at high risk of future ACL rupture . Consequently , individual preventive efforts can be introduced in time . However , large prospect i ve studies are needed to confirm this finding before definitive clinical recommendations can be made PURPOSE The aim of this study was to determine the rates of contralateral anterior cruciate ligament ( ACL ) rupture and of ACL graft rupture after  ACL reconstruction  using either patellar tendon or hamstring tendon autograft , and to identify any patient characteristics that may increase this risk . TYPE OF STUDY Case series . METHODS Over a 2-year period , 760 endoscopic ACL reconstructions were performed in 743 patients .  Bone-patellar tendon-bone autograft was used in 316 patients and 4-str and hamstring tendon in 427 patients . Those patients with a previous contralateral ACL rupture or those who underwent a simultaneous bilateral ACL reconstruction were excluded , leaving 675 knees ( 675 patients ) for review . Persons not involved in the index operation or the care of the patient conducted follow-up assessment by telephone interview conducted 5 years after surgery . Patients were question ed about the incidence of ACL graft rupture , contralateral ACL rupture , symptoms of instability or significant injury , family history of ACL injury , and activity level according to the International Knee Documentation Committee scale . From our prospect i ve data base we obtained further information on graft source , meniscal or articular surface injury , and gender . Binary logistic regression was used to measure the relative association between the measured variables and the risk of graft rupture and contralateral ACL rupture . RESULTS Five years after primary ACL reconstruction , 612 of the 675 patients ( 90.7 % ) were assessed . ACL graft rupture occurred in 39 patients ( 6 % ) and contralateral ACL rupture occurred in 35 patients ( 6 % ) . Three patients suffered both a graft rupture and a contralateral ACL injury . The odds of ACL graft rupture were increased 3-fold by a contact mechanism of initial injury . Return to level 1 or 2 sports increased the risk of contralateral ACL injury by a factor of 10 . The risk of sustaining an ACL graft rupture was greatest in the first 12 months after reconstruction . No other studied variable increased the risk of repeat ACL injury . CONCLUSIONS After reconstruction , repeat ACL injury occurred in 12 % of patients over 5 years . Twelve months after reconstruction , the ACL graft is at no greater risk than the contralateral ACL , suggesting that adequate graft and muscular function for most activities is achieved by this time . Risk factors for repeat ACL injury identified included a return to competitive side-stepping , pivoting , or jumping sports , and the contact mechanism of the index injury . Female patients were at no greater risk of repeat ACL injury than male patients and graft choice did not affect the rate of repeat ACL injury . LEVEL OF EVIDENCE Level IV , case series The efficacy of two non-operative rehabilitation programs was studied in a consecutive r and omized controlled clinical trial of 100 patients after 12 months subsequent to an acute anterior cruciate ligament ( ACL ) injury . Follow up of r and omization to two training models was evaluated after 3 and 12 months : A self-monitored training program ( SM ) of traditional mobility and muscle strength training of the injured leg was compared to a supervised ( SV ) training model exercising postural function in closed kinetic-chains . Nearly 50 % of the patients in the SM group required supervision after 6 weeks . An intention-to-treat analysis was performed and showed significantly better values in most of the results of the supervised group at 3 and 12 months . An alternative analysis of subgroups showed a significant difference between transferred male patients and original SV male patients at 3 months but not at 12 months , indicating the importance of initial guiding after an ACL injury . No such difference was observed in the female patients
Conclusion : The literature suggests an association between hormonal fluctuations and ACL injury .
Recent studies have suggested that oral contraceptives may offer up to a 20 % reduction in risk of injury .
Background : Women are at substantially greater risk for anterior cruciate ligament ( ACL ) injuries than are men .
Purpose : To conduct a systematic review and meta- analysis of the literature to clarify the effect of the menstrual cycle and contraceptives on the laxity of and noncontact injuries to the ACL .