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 Risk Factors Associated with Noncontact Injury of the Anterior Cruciate Ligament Hormonal therapy: ACL and ankle injury. Neuromuscular control training programs and noncontact anterior cruciate ligament injury rates in female athletes: a numbers-needed-to-treat analysis. Relationship of the menstrual cycle phase to anterior cruciate ligament injuries in teenaged female athletes A comparison of Telos™ stress radiography versus Rolimeter™ in the diagnosis of different patterns of anterior cruciate ligament tears. A prospective cohort study of anterior cruciate ligament injuries in elite Norwegian team handball. The Menstrual Cycle, Sex Hormones, and Anterior Cruciate Ligament Injury. A Randomized Controlled Trial to Prevent Noncontact Anterior Cruciate Ligament Injury in Female Collegiate Soccer Players A Prospective Evaluation of the Landing Error Scoring System (LESS) as a Screening Tool for Anterior Cruciate Ligament Injury Risk Anterior cruciate ligament repair with LARS (ligament advanced reinforcement system): a systematic review Anatomic Reconstruction of the Anterior Cruciate Ligament of the Knee With or Without Reconstruction of the Anterolateral Ligament: A Randomized Clinical Trial The effect of patient and injury factors on long-term outcome after anterior cruciate ligament reconstruction Incidence of Contralateral and Ipsilateral Anterior Cruciate Ligament (ACL) Injury After Primary ACL Reconstruction and Return to Sport Identification of Athletes at Future Risk of Anterior Cruciate Ligament Ruptures by Neuromuscular Screening Bone Bruises Associated with ACL Rupture Three distinct mechanisms predominate in non-contact anterior cruciate ligament injuries in male professional football players: a systematic video analysis of 39 cases Incidence and risk factors for graft rupture and contralateral rupture after anterior cruciate ligament reconstruction. Risk Factors Associated With Grade 3 Pivot Shift After Acute Anterior Cruciate Ligament Injuries Post-operative use of knee brace in bone-tendon-bone patellar tendon anterior cruciate ligament reconstruction: 5-year follow-up results of a randomized prospective study. Intercondylar notch size and anterior cruciate ligament injuries in athletes Can magnetic resonance imaging findings predict the degree of knee joint laxity in patients undergoing anterior cruciate ligament reconstruction?
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 : 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 BACKGROUND No definitive explanation for the difference in rate of male and female noncontact ACL injury has been found . The hormonal environment , known to be different in men and women has been hypothesized as a possible source for this difference in injury rate . PURPOSE To confirm earlier work looking at periodicity of noncontact ACL injury . To increase sample size by adding ankle sprains . To determine the rate of  noncontact ACL injury and ankle sprains in collegiate basketball and soccer . To determine if the use of oral contraceptives affects the rate of noncontact ACL injury and ankle sprains . METHODS Data was collected from a sample of NCAA schools over the 2000 - 2001 basketball and the 2001 - 2002 basketball and soccer seasons . RESULTS Recall and prospect i ve data collection of length of menstrual cycle did not produce equivalent results . Periodicity was present only in the recall group of " off pill " users . The rate of noncontact ACL injury and noncontact ankle sprains was twice as high in basketball as in soccer . There was no difference in rate of injuries between those athletes using  hormonal therapy and those athletes not using hormonal therapy . CONCLUSIONS Noncontact ACL injuries and ankle sprains occurred at significantly higher rates in basketball than in soccer but this rate difference was not linked to hormonal therapy usage . The overall rate of noncontact ACL injury and ankle sprain to women 's collegiate basketball and soccer players is very low OBJECTIVE To determine the numbers needed to treat ( NNT ) and relative risk reduction ( RRR ) associated with neuromuscular training programs aim ed at preventing noncontact anterior cruciate ligament ( ACL ) injuries in female athletes . DATA SOURCES We search ed PubMed , MEDLINE , SPORT Discus , CINAHL , and Web of Science from 1966 through 2005 using the terms knee , injury , anterior cruciate ligament , ACL , prevention , plyometric , and neuromuscular training . STUDY SELECTION Selected articles were from peer- review ed journals written in English that described original research studies comparing neuromuscular training programs with control programs to determine the number of noncontact ACL injuries per event exposure or hours of playing time . Five studies met the inclusion criteria and were independently rated by 3 review ers using the Physiotherapy Evidence Data base ( PEDro ) scale . Consensus PEDro scores ranged from 4 to 7 out of 10 . DATA EXTRACTION We used numbers of subjects , ACL injuries , and injury exposure rates to calculate NNT and RRR for each study . The NNT calculations from all studies were based on the number of players across 1 competitive season and were described as NNT benefit or NNT harm . DATA SYNTHESIS All 5 studies demonstrated a prophylactic effect due to the neuromuscular training programs . The pooled NNT estimates showed that 89 individuals ( 95 % confidence interval : 66 to 136 ) would need to participate in the prophylactic training program to prevent 1 ACL injury over the course of 1 competitive season . Pooled RRR was 70 % ( 95 % confidence interval : 54 % to 80 % ) among individuals who participated in the intervention program . One high- quality r and omized control trial and 4 medium- quality prospect i ve cohort studies showed mostly consistent findings . Thus , a Strength of Recommendation Taxonomy level of evidence of 1 with a grade B recommendation supports the use of neuromuscular training programs in the prevention of noncontact ACL injuries in female athletes 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 INTRODUCTION Our knowledge on anterior cruciate ligament ( ACL ) pathomechanics has increased . The diagnosis of partial ACL tears must be accurate in order to adjust the operative planning to anatomic status and injury severity . Instrumented measurement of knee laxity is a useful preoperative tool to quantify anterior tibial translation and several laximetry tests are available . Yet , their accuracy remains to be established . HYPOTHESIS Clinical examination combined to instrumented laximetry with Telos ™ 15 kg and /or Rolimeter ™ would increase their sensitivity and specificity in the diagnosis of various ACL injury patterns . MATERIAL S AND METHODS One hundred and seventy-seven patients were prospect ively included . The ACL status was vali date d by arthroscopy . Around 69.5 % had a complete ACL tear and 30.5 % had a partial ACL tear . RESULTS Gross laxity with positive clinical tests was associated with complete ACL tears . Mean side-to-side difference was significantly greater with both laximetry methods in complete versus partial ACL tears . Laximetry results among different types of partial tears were not significantly different . Telos ™ results were consistent with gross laxity confirmed by pivot-shift test , while this was not recorded with Rolimeter ™ . Gross laxity with clinical tests and anterior tibial translation more than 5 mm with Telos ™ were substantially associated with complete ACL tears . DISCUSSION The combination of st and ard clinical examination with Telos ™ was more accurate than with Rolimeter ™ in the preoperative identification of the ACL injury pattern . Applying additional diagnostic tools can help the surgeon to preoperatively diagnose partial or complete ACL ruptures and propose an injury-specific surgical treatment . LEVEL OF EVIDENCE Level III ( case-control study ) 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 : 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 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 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 Injury to the anterior cruciate ligament ( ACL ) of the knee is common . Following complete rupture of the ACL , insufficient re-vascularization of the ligament prevents it from healing completely , creating a need for reconstruction . A variety of grafts are available for use in ACL reconstruction surgery , including synthetic grafts . Over the last two decades new types of synthetic ligaments have been developed . One of these synthetic ligaments , the Ligament Advanced Reinforcement System ( LARS ) , has recently gained popularity . The aim of this systematic review was to assess the current best available evidence for the effectiveness of the LARS as a surgical option for symptomatic , anterior cruciate ligament rupture in terms of graft stability , rehabilitation time and return to pre-injury function . Method This systematic review included studies using subjects with symptomatic , ACL ruptures undergoing LARS reconstruction .  A range of electronic data bases were search ed in May 2010 . The method ological quality of studies was appraised with a modified version of the Law critical appraisal tool . Data relating to study characteristics , surgical times , complication rates , outcomes related to knee stability , quality of life , function , and return to sport as well as details of rehabilitation programs and timeframes were collected . Results This review identified four studies of various design s , of a moderate method ological quality . Only one case of knee synovitis was reported . Patient satisfaction with LARS was high . Graft stability outcomes were found to be inconsistent both at post operative and at follow up periods . The time frames of rehabilitation periods were poorly reported and at times omitted . Return to pre-injury function and activity was often discussed but not reported in results . Conclusions There is an emerging body of evidence for LARS with comparable complication rates to traditional surgical techniques , and high patient satisfaction scores . However , this systematic review has highlighted several important gaps in the existing literature that require future prospect i ve investigation . The findings of this review were equivocal with regards to other measures such as graft stability and long term functional outcomes . While the importance of rehabilitation following LARS is well recognised , there is limited evidence to guide rehabilitation protocol Background : Rotational instability of the knee remains an issue after  anterior cruciate ligament ( ACL ) reconstruction .  Hypothesis/ Purpose : The purpose was to evaluate the subjective and objective outcomes of combined reconstruction of the ACL and anterolateral ligament ( ALL ) of the knee . The hypothesis was that favorable outcomes can be achieved with this surgical procedure compared with isolated anatomic reconstruction of the ACL . Study Design : R and omized controlled trial ; Level of evidence , 2 . Methods : One hundred ten patients with a unilateral ACL injury and high- grade pivot shift were r and omly assigned to undergo either combined ACL and ALL reconstruction ( group A ) or isolated ACL reconstruction  ( group B ) . Preoperative and postoperative evaluations of the patients were conducted by obtaining history details , recording physical examination findings , measuring knee laxity using the KT-1000 arthrometer , and using vali date d outcome scores for the knee . P < .05 was considered as the cut-off level of statistical significance . The Fisher exact and Mann-Whitney U tests were used to assess statistical significance . Results : At a mean follow-up of 27 months , 53 and 50 patients in groups A and B , respectively , were available for analysis . No statistically different outcomes were found between the 2 groups except for the KT-1000 arthrometer values . The median KT-1000 arthrometer result for combined ACL and ALL reconstruction was 1.3 mm , while the median result for isolated ACL reconstruction was 1.8 mm ( P < .001 ) . None of the patients ( n = 0 ; 0.0 % ) who underwent combined ACL and ALL reconstruction had anterior translation of greater than 5 mm at maximum pulling strength compared with their normal knees at final follow-up . On the other h and , 3 ( 6.0 % ) patients who underwent isolated ACL reconstruction had anterior translation of more than 5 mm . No serious complications were found in both groups . Conclusion : Combined ACL and ALL reconstruction was found to be effective in improving subjective and objective outcomes . Nevertheless , these findings were not significantly superior to isolated ACL reconstruction except for the instrumented knee laxity testing results . This might indicate that ALL reconstruction should not be performed routinely for patients undergoing ACL reconstruction Background Long-term follow-up is required for accurate assessment of results after  anterior cruciate ligament ( ACL ) reconstruction  and recent years have witnessed the publication of numerous papers detailing long-term outcomes . The primary aim of this systematic review was to determine which patient factors affect long-term clinical and radiographic outcomes based on the current literature . Methods A comprehensive literature review yielded 18 prospect i ve manuscripts with minimum follow-up ranging from 5 - 12 years after ACL reconstruction .  Results Longer follow-up was associated with increased radiographic evidence of osteoarthritis . Increased meniscal or articular cartilage pathology at ACL reconstruction were found to be associated with increased prevalence of radiographic evidence of osteoarthritis at long-term follow-up in most studies . There is currently insufficient evidence to correlate these intra-articular findings with decreases in clinical outcome measures . Further research is needed to determine the effect of body mass index ( BMI ) on long-term outcome after ACL reconstruction . Conclusions Intra-articular injuries noted at the time of ACL reconstruction affect long-term results . The effect of BMI and other patient factors is unclear . Long-term follow-up of large multicenter cohorts will provide definitive data on the relative importance of different factors in determining results of ACL reconstruction 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 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 Background Different patterns of bone bruising are seen on magnetic resonance imaging in acute anterior cruciate ligament ruptures . These patterns may relate to the mechanism of injury . Hypothesis There is a correlation between the mechanism of anterior cruciate ligament injury and bone bruise patterns on magnetic resonance imaging . Study Design Cohort study ; Level of evidence , 2 . Methods Data regarding the mechanism of anterior cruciate ligament rupture were collected prospect ively on patients who had anterior cruciate ligament reconstructions . Inclusion criteria included a clear history of mechanism , magnetic resonance imaging within 6 weeks of injury , and no previous knee injury . Patients were divided into noncontact and contact mechanism groups . Bone bruise frequency , location , depth , and intensity were analyzed using magnetic resonance imaging and correlated with the mechanism of injury . Results Two hundred fifty-six patients were identified ; 100 met the inclusion criteria , 86 were in the noncontact mechanism group , and 14 were in the contact mechanism group . The proportion of bone bruises in the lateral compartment in both groups was higher ( P < .001 ) than in the medial compartment . Bone bruising was more frequent , deeper , and more intense in the non-contact group , with frequency ( P = .019 ) and intensity ( P < .001 ) scores reaching significance at the lateral tibial plateau . Medial compartment bone bruising was seen more frequently than previously reported , particularly in the noncontact group . Conclusion The noncontact mechanism appears to cause more severe bone bruising in both the medial and lateral compartments Background Current knowledge on anterior cruciate ligament ( ACL ) injury mechanisms in male football players is limited . Aim To describe ACL injury mechanisms in male professional football players using systematic video analysis . Methods We assessed  videos from 39 complete ACL tears recorded via prospect i ve professional football injury surveillance between 2001 and 2011 . Five analysts independently review ed all videos to estimate the time of initial foot contact with the ground and the time of ACL tear . We then analysed all videos according to a structured format describing the injury circumstances and lower limb joint biomechanics . Results Twenty-five injuries were non-contact , eight indirect contact and six direct contact injuries . We identified three main categories of non-contact and indirect contact injury situations : ( 1 ) pressing ( n=11 ) , ( 2 ) re-gaining balance after kicking ( n=5 ) and ( 3 ) l and ing after heading ( n=5 ) . The fourth main injury situation was direct contact with the injured leg or knee ( n=6 ) . Knee valgus was frequently seen in the main categories of non-contact and indirect contact playing situations ( n=11 ) , but a dynamic valgus collapse was infrequent ( n=3 ) . This was in contrast to the tackling-induced direct contact situations where a knee valgus collapse occurred in all cases ( n=3 ) . Conclusions Eighty-five per cent of the ACL injuries in male professional football players result ed from non-contact or indirect contact mechanisms . The most common playing situation leading to injury was pressing followed by kicking and heading . Knee valgus was frequently seen regardless of the playing situation , but a dynamic valgus collapse was rare 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 Background : Recent literature has demonstrated that involvement in pivoting sports at the time of injury , increased posterior-inferior tibial slope ( PITS ) , anterolateral capsular ligament ( ALCL ) disruptions , and combined lateral meniscal lesions all contribute to a higher grade of pivot shift after acute anterior cruciate ligament ( ACL ) injuries . Purpose : To identify risk factors associated with grade 3 pivot shift after acute ACL injuries . Study Design : Case-control study ; Level of evidence , 3 . Methods : A data base of patients undergoing primary ACL reconstruction from 2009 to 2015 after acute ACL injuries was retrospectively review ed . A total of 30 patients ( 30 knees ) with grade 3 pivot shift were identified as the study group . Moreover , 30 patients ( 30 knees ) with grade 1 and 30 patients ( 30 knees ) with grade 2 pivot shift were r and omly chosen as the 2 control groups . All pivot-shift tests were performed with the patients under anesthesia . Predictors of grade 3 pivot shift that were explored included patient age , sex , time from injury to surgery , pivoting sports involvement at the time of injury , lateral PITS , medial PITS , ALCL disruptions , preoperative KT-1000 arthrometer side-to-side difference , and combined lateral or medial meniscal lesions . Comparisons were performed between the study group and the 2 control groups . Univariable and multivariable logistic regressions were used to identify independent risk factors that were associated with grade 3 pivot shift . Results : Univariable and multivariable logistic regressions between the study group and the 2 control groups showed that  pivoting sports involvement  at the time of injury ( odds ratio1 [ OR1 ; grade 3 vs grade 1 pivot shift with grade 1 = reference ] , 11.88 ; 95 % CI , 1.94 - 149.91 ; OR2 [ grade 3 vs grade 2 pivot shift with grade 2 = reference ] , 3.41 ; 95 % CI , 1.92 - 22.60 ) , abnormal degree of lateral PITS ( OR1 , 14.41 ; 95 % CI , 1.69 - 174.78 ; OR2 , 6.41 ; 95 % CI , 1.48 - 47.70 ) , ALCL disruptions ( OR1 , 8.28 ; 95 % CI , 1.71 - 117.14 ; OR2 , 4.96 ; 95 % CI , 1.07 - 28.75 ) , and combined lateral meniscal lesions ( OR1 , 27.56 ; 95 % CI , 5.48 - 240.52 ; OR2 , 5.83 ; 95 % CI , 1.21 - 38.56 ) were independent risk factors of grade 3 pivot shift after acute ACL injuries . Conclusion : For acute ACL injuries , the best set of predictors of grade 3 pivot shift were pivoting sports involvement at the time of injury , abnormal lateral PITS , ALCL disruptions , and combined lateral meniscal lesions . These results may provide additional information for counseling patients on residual laxity and risks for graft rerupture after ACL reconstruction Sixty patients were prospect ively r and omized  to  brace and no-brace groups after bone-tendon-bone patellar tendon anterior cruciate ligament ( ACL ) reconstruction .  The brace group wore a rehabilitation knee brace for 12 weeks post-operatively , while the no-brace  group was mobilized immediately , and crutches were discarded 2 weeks post-operatively . The groups were comparable with respect to age , gender , time from injury to surgery and concomitant injuries . There were no differences either pre-operatively or 5 years post-operatively ( 80 % of patients review ed ) between the groups in terms of the knee score ( Lysholm ) , activity level ( Tegner ) , degree of laxity or isokinetic peak muscle torque . Thus it appears that knee braces are not needed in the post-operative rehabilitation after ACL reconstruction with the patellar tendon graft Published reports agree that there is a strong associa tion between intercondylar notch stenosis and anterior cruciate ligament injuries . In a previously published retrospective study on bilateral anterior cruciate liga ment injuries and associated intercondylar notch ste nosis , we formulated the notch width index to measure and compare intercondylar notch width . The purpose of this prospect i ve study was to establish a normal range for the notch width index and to correlate inter condylar notch size and anterior cruciate ligament in juries . We gathered data on 902 high school athletes , including range of motion , thigh girth , ligament stability and intercondylar notch width using the notch width index .  The population was then followed prospect ively and anterior cruciate ligament injuries were recorded and correlated with notch width index in a blind manner . Two-year results showed that the overall anterior cru ciate ligament injury rate was 3 % . The normal intercon dylar notch ratio was 0.231 ± 0.044 . Intercondylar notch width index for men was larger than that for women . Athletes sustaining noncontact anterior cru ciate ligament tears have statistically significant inter condylar notch stenosis ( notch width index , 0.189 ) . Ten of 14 athletes with noncontact anterior cruciate liga ment injuries had a notch width index that was at least 1 SD below the mean . Athletes with contact anterior cruciate ligament injuries had a mean of 0.233 . We conclude that athletes with a stenotic intercondylar notch are at significantly greater risk for sustaining noncontact anterior cruciate ligament injury Background The present study was performed to determine whether MRI findings can predict the degree of knee joint laxity in patients undergoing ACL reconstruction and whether the accuracy of the prediction is affected by the MRI acquisition time . Methods We assessed prospect ively collected data of 154 knees with ACL tears . The presence or absence of four primary findings of ACL tears , i.e. , nonvisualization , discontinuity , abnormal signal intensity , and abnormal shape of the ACL , and five secondary findings , i.e. , anterior translation of the tibia relative to the femur ( ≥7 mm ) , posterior cruciate ligament angle ( < 105 ° ) , bone contusion , Segond fracture , and the deep sulcus sign , were determined . Knee joint laxity was assessed using the Lachman and pivot shift tests . The associations between MRI findings and clinical ly assessed knee joint laxity were analyzed and compared between subgroups ( ≤3 months from injury to MRI , 89 knees ; > 3 months , 65 knees ) . Results Nonvisualization was related to the results of the Lachman test [ Odds ratio ( OR ) , 2.6 ; 95 % confidence interval ( CI ) , 1.2–5.5 ] . Anterior translation of the tibia relative to the femur was related to the results of the pivot shift test ( OR , 3.8 ; 95 % CI , 1.6–9.4 ) . In subgroup comparisons of the early and late MRI groups , anterior translation of the tibia relative to the femur was related to the results of the pivot shift test in the early MRI group ( OR , 4.5 ; 95 % CI , 1.4–14.4 ) . In contrast , no MRI findings had statistically significant relationships with physical findings in the late MRI group . Conclusions Our study indicates that MRI findings may have some usefulness for predicting the grade of knee laxity in patients with symptomatic ACL injury , but its value is limited , especially in patients with a longer time interval between injury and the performance of MRI
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 .