Anterior Cruciate Ligament Injury In Athletes Research Articles

The Impact of Genetic Polymorphisms on Anterior Cruciate Ligament Injuries in Athletes: A Meta-Analytical Approach.

This meta-analysis aimed to investigate the association between genetic polymorphisms in Collagen type 1 alpha-1 (COL1A1), Collagen type 3 alpha-1 (COL3A1), Collagen type 5 alpha-1 (COL5A1), and Collagen type 12 alpha-1 (COL12A1) genes and anterior cruciate ligament (ACL) injuries in athletes. A systematic search was diligently conducted on the PubMed and Web of Science databases to identify relevant studies on 5-9 September 2023. Only case-control studies were included in the meta-analysis. A total of 19 studies were reviewed, involving the analysis of 3522 cases and 6399 control subjects. Data relevant to the study objectives were extracted from these chosen studies and subsequently analyzed using either a random-effects or fixed-effects model. It indicates that individuals carrying the G allele in the COL1A1 (rs1107946) gene have a decreased risk of anterior cruciate ligament injuries (OR: -0.27, 95% CI: -0.42 to -0.12, p < 0.001). A similar relationship was observed in the dominant model, but this relationship was reversed in the recessive model (OR: 0.69, 95% CI: 0.33 to 1.05, p < 0.001). However, no significant associations were found in the COL3A1 (rs1800255) and COL5A1 (rs12722) genes. In the COL12A1 (rs970547) gene, the A allele was associated with an increased risk of anterior cruciate ligament injuries (OR: 0.18, 95% CI: 0.01 to 0.36, p = 0.041). This meta-analysis suggests that genetic variants in COL1A1 (rs1107946) and COL12A1 (rs970547) may be associated with ACL injuries in athletes. However, COL3A1 rs1800255 and COL5A1 rs12722 gene variants do not appear to have a significant association with these injuries.

Two cases of contact athletes with anterior cruciate ligament injuries who returned to competition early after conservative treatment with PRP therapy

IntroductionAnterior cruciate ligament (ACL) injuries in high-impact contact sports athletes are often treated through surgery. Recently, conservative treatment of ACL injuries in athletes using autologous biotherapy such as platelet-rich plasma (PRP) has been reported. We report two cases of aggressive conservative treatment with PRP therapy for contact athletes.Presentation of caseCase 1. A 23-year-old male rugby player with a preinjury Tegner score of 9 underwent three PRP treatments following an ACL injury and returned to preinjury levels of play 4 months postinjury. The pivot shift test had improved to grade 0 at the last follow-up. Case 2. A 34-year-old male mixed martial arts fighter with a preinjury Tegner score of 9 underwent five PRP treatments following an ACL injury and returned to his preinjury play level 3.5 months postinjury. Both contact athletes returned to competition early and continued to compete without losing stability at the final follow-up. Moreover, their functional score exceeded the median score for athletes after ACL reconstruction, suggesting satisfactory performance.DiscussionAntiinflammatory cytokines and growth factors in PRP may promote graft maturation and alter the natural history of remodeling, resulting in earlier and firmer graft maturation, improving both the duration and quality of the healing process.ConclusionTwo high-impact sports athletes with ACL injuries were treated with aggressive conservative therapy using PRP and returned early to their preinjury play level.

Rehabilitation and Return to Sport Testing After Anterior Cruciate Ligament Reconstruction: Where Are We in 2022?

AbstractAthletes who sustain an anterior cruciate ligament (ACL) injury often opt for an ACL reconstruction (ACLR) with the goal and expectation to return to sports at the preinjury level. The proportion of athletes who successfully return to preinjury-level sport is low and disappointing, whereas the rate of second ACL injury in athletes under the age of 20 has been reported to be as high as 40% after return to sport (RTS). Although in recent years, new insights pertaining to RTS have been published, the lack of validity of RTS criteria after ACLR remain. The purpose of this clinical commentary is to present a critical overview of the current literature on RTS testing after ACLR.

Three genes associated with anterior and posterior cruciate ligament injury : a genome-wide association analysis.

AimsThe aim of this study was to screen the entire genome for genetic markers associated with risk for anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) injury.MethodsGenome-wide association (GWA) analyses were performed using data from the Kaiser Permanente Research Board (KPRB) and the UK Biobank. ACL and PCL injury cases were identified based on electronic health records from KPRB and the UK Biobank. GWA analyses from both cohorts were tested for ACL and PCL injury using a logistic regression model adjusting for sex, height, weight, age at enrolment, and race/ethnicity using allele counts for single nucleotide polymorphisms (SNPs). The data from the two GWA studies were combined in a meta-analysis. Candidate genes previously reported to show an association with ACL injury in athletes were also tested for association from the meta-analysis data from the KPRB and the UK Biobank GWA studies.ResultsThere was a total of 2,214 cases of ACL and PCL injury and 519,869 controls within the two cohorts, with three loci demonstrating a genome-wide significant association in the meta-analysis: INHBA, AEBP2, and LOC101927869. Of the eight candidate genes previously studied in the literature, six were present in the current dataset, and only COL3A1 (rs1800255) showed a significant association (p = 0.006).ConclusionGenetic markers in three novel loci in this study and one previously-studied candidate gene were identified as potential risk factors for ACL and PCL injury and deserve further validation and investigation of molecular mechanisms.Cite this article: Bone Jt Open 2021;2(6):414–421.

Efficient Detection of Knee Anterior Cruciate Ligament from Magnetic Resonance Imaging Using Deep Learning Approach.

The most commonly injured ligament in the human body is an anterior cruciate ligament (ACL). ACL injury is standard among the football, basketball and soccer players. The study aims to detect anterior cruciate ligament injury in an early stage via efficient and thorough automatic magnetic resonance imaging without involving radiologists, through a deep learning method. The proposed approach in this paper used a customized 14 layers ResNet-14 architecture of convolutional neural network (CNN) with six different directions by using class balancing and data augmentation. The performance was evaluated using accuracy, sensitivity, specificity, precision and F1 score of our customized ResNet-14 deep learning architecture with hybrid class balancing and real-time data augmentation after 5-fold cross-validation, with results of 0.920%, 0.916%, 0.946%, 0.916% and 0.923%, respectively. For our proposed ResNet-14 CNN the average area under curves (AUCs) for healthy tear, partial tear and fully ruptured tear had results of 0.980%, 0.970%, and 0.999%, respectively. The proposing diagnostic results indicated that our model could be used to detect automatically and evaluate ACL injuries in athletes using the proposed deep-learning approach.

Comparison of Quadriceps Muscle Girth Using Ultrasound Imaging In Supervised vs Unsupervised Post Operative ACL Reconstruction

Injury to the anterior cruciate ligament (ACL) is one of the most common knee ligament injuries. The ACLinjury is a sprain or tear of the anterior ligament (ACL). Effective exercises will reduce the risk of ACLinjury. An ACL injury in athletes is a higher incidence than other general public, such as soccer, basketball,hockey, etc. The aim of this studywas to compare the effectiveness, recovery rate and variance in bothknee-affected and non-affected muscle girth readings in supervised v/s unsupervised patient groups after thepatient underwent ACL reconstruction surgery. The participants were divided into two groups(A-Supervisedand B-Unsupervised) through a random sampling. The supervised exercise in group A performed accordingto the WILK protocol at RML hospital and un-superviseed group B performed the same WILK protocol athome. The ultrasound scans were performed after 2-4 weeks and 12-14 weeks post operation to measurethe muscle girth in both the groups. The study findings indicated the significant difference in recovery rateas well as the difference in between supervisedv/s unsupervised groups i.e. the difference of affected andunaffected knees based on ultrasound imaging was higher in un-supervised group compared to supervisedgroup (a difference of 2.3 mm in post-operation muscle girth after 12-14 weeks). The ultrasound readingof the muscle girth after 2-4 weeks post-operation showed a decline in the recovery of the muscle girth inboth the groups (9% and 8% for supervised and un-supervised groups respectively). This reduction in themuscle girth value as compared to the pre-operative values was due to arthroscopic effect, which showedthere was a transient deactivation of the muscle take place due to surgery. The ultrasound reading of themuscle girth after 12-14 weeks post-operation showed a different progressive recovery of the muscle girth inboth the groups as 31% and 10% for supervised and un-supervised groups respectively .We concluded thatsupervised exercises was better than unsupervised exercises for the early recovery after ACL recontraction.

Anterior Cruciate ligament injuries of the knee:

Abstract&#x0D; Background and problem statement&#x0D; Anterior cruciate ligament injuries are common among athletes and the general public. These injuries may lead to significant absence from activity with an associated financial and social burden. No definitive association has been described between mechanism of injury and pathology to enable us to put preventative measures in place in order to limit these injuries.&#x0D; Aim&#x0D; To determine whether there is an association between the mechanism of injury and the pathology seen on a magnetic resonance imaging (MRI) scan in anterior cruciate ligament (ACL) injuries.&#x0D; Methods&#x0D; This was a cross-sectional analytical study. Eighty seven male patients with an ACL injury, who had an MRI scan of the knee within the last two years participated in this study. Participants were contacted to give consent that their information be used in this study. The mechanism of injury and the pathology seen on the MRI scan was noted and categorised into different mechanism of injury groups and associated pathology groups. Statistical analyses included summaries of the data and a test for association between mechanism of injury and pathology. Since there were multiple pathology responses to each mechanism, a modified version of the chi-square test for independence was used. A 5% level of significance was specified.&#x0D; Results&#x0D; MRI scans of ACL injuries indicated that the mechanism of a solid foot plant with rotation of the knee has a greater tendency to be associated with medial meniscal injuries (77%), and also a 54% possibility to be associated with lateral meniscal injuries. A solid foot plant with a valgus stress on the knee showed a higher incidence of associated medial collateral ligaments (MCL) injuries (41%) and femoral bone bruising (62 %). These two mechanisms of injury are the most common in ACL injuries and contribute to the clinical significance found in this study. The p-value was however not statistically significant (p=0.44, chi-square value=20.27, df=45) for any association between pathology and mechanism of injury.&#x0D; Conclusion&#x0D; Some injury mechanisms causing ACL injury were more common than others and also had more associated pathology. The most common mechanism of injury noted is a solid foot plant with either rotation of the knee or valgus stress on the knee. Strengthening tissue structures involved in those movement patterns that cause these mechanisms can possibly limit ACL injuries in athletes and the general public.&#x0D;  Key words&#x0D; Anterior cruciate ligament injury, mechanism, association, pathology, MRI scan, prevention.

Anterior Cruciate ligament injuries of the knee:

Abstract&#x0D; Background and problem statement&#x0D; Anterior cruciate ligament injuries are common among athletes and the general public. These injuries may lead to significant absence from activity with an associated financial and social burden. No definitive association has been described between mechanism of injury and pathology to enable us to put preventative measures in place in order to limit these injuries.&#x0D; Aim&#x0D; To determine whether there is an association between the mechanism of injury and the pathology seen on a magnetic resonance imaging (MRI) scan in anterior cruciate ligament (ACL) injuries.&#x0D; Methods&#x0D; This was a cross-sectional analytical study. Eighty seven male patients with an ACL injury, who had an MRI scan of the knee within the last two years participated in this study. Participants were contacted to give consent that their information be used in this study. The mechanism of injury and the pathology seen on the MRI scan was noted and categorised into different mechanism of injury groups and associated pathology groups. Statistical analyses included summaries of the data and a test for association between mechanism of injury and pathology. Since there were multiple pathology responses to each mechanism, a modified version of the chi-square test for independence was used. A 5% level of significance was specified.&#x0D; Results&#x0D; MRI scans of ACL injuries indicated that the mechanism of a solid foot plant with rotation of the knee has a greater tendency to be associated with medial meniscal injuries (77%), and also a 54% possibility to be associated with lateral meniscal injuries. A solid foot plant with a valgus stress on the knee showed a higher incidence of associated medial collateral ligaments (MCL) injuries (41%) and femoral bone bruising (62 %). These two mechanisms of injury are the most common in ACL injuries and contribute to the clinical significance found in this study. The p-value was however not statistically significant (p=0.44, chi-square value=20.27, df=45) for any association between pathology and mechanism of injury.&#x0D; Conclusion&#x0D; Some injury mechanisms causing ACL injury were more common than others and also had more associated pathology. The most common mechanism of injury noted is a solid foot plant with either rotation of the knee or valgus stress on the knee. Strengthening tissue structures involved in those movement patterns that cause these mechanisms can possibly limit ACL injuries in athletes and the general public.&#x0D;  Key words&#x0D; Anterior cruciate ligament injury, mechanism, association, pathology, MRI scan, prevention.

Prevention of knee injuries and ACL ruptures Systematic review and recommendations of the the German Knee Society (DKG): The Stop-X program

Aims and Objectives: Introduction Knee injuries and especially anterior cruciate ligament (ACL) tears are frequent in athletes. Therefore, primary and secondary prevention of sports-related lower limb injuries is an ongoing topic of interest. The aim of present study was to establish guidelines for the prevention of knee and ACL injuries on the basis of evidence-based concepts represented in current literature. Methods: A comprehensive literature review regarding prevention programs for knee and ACL injuries was conducted. Results: Several modifiable and non-modifiable risk factors for knee injuries in athletes have been reported in literature. Referring to the ACL, specific injury mechanisms have been identified and are well understood. In particular, it has been demonstrated that dynamic valgus is one of the most important modifiable risk factors. Simple tests like the drop jump test have shown their efficacy in screening and detecting athletes at risk. There is only little evidence for the preventive effect on knee and ACL injuries by single exercises. However, in order to prevent or correct endangering movement patterns including dynamic valgus, several complex prevention programs have been developed in the past. These prevention programs are included in standard warm-up exercises and are focusing on muscle strength, balance, and proprioception, as well as running and flexibility. It is reported that these training programs can reduce the incidence of knee injuries by up to 27% and ACL injuries by up to 51%. Conclusions Screening, identification, and correction of endangering movement patterns like the dynamic valgus are the first crucial steps in order to prevent knee and ACL injuries in athletes. Furthermore, jumping, running and flexibility exercises as well as balance and strength training are proven to reduce the incidence of these injuries and should, therefore, be integrated into the regular warm up program. Appropriate complete prevention programs are freely accessible via the Internet and should be adapted to the specific sport disciplines

Evidence-based concepts for prevention of knee and ACL injuries. 2017 guidelines of the ligament committee of the German Knee Society (DKG).

Knee injuries and especially anterior cruciate ligament (ACL) tears are frequent in athletes. Therefore, primary and secondary prevention of sports-related lower limb injuries is an ongoing topic of interest. The aim of present study was to establish guidelines for the prevention of knee and ACL injuries on the basis of evidence-based concepts represented in current literature. A comprehensive literature review regarding prevention programs for knee and ACL injuries was conducted. Several modifiable and non-modifiable risk factors for knee injuries in athletes have been reported in literature. Referring to the ACL, specific injury mechanisms have been identified and are well understood. In particular, it has been demonstrated that dynamic valgus is one of the most important modifiable risk factors. Simple tests like the drop jump test have shown their efficacy in screening and detecting athletes at risk. There is only few evidence for the preventive effect on knee and ACL injuries by single exercises. However, in order to prevent or correct endangering movement patterns including dynamic valgus, several complex prevention programs have been developed in the past. These prevention programs are included in standard warm-up exercises and are focusing on muscle strength, balance, and proprioception, as well as running and flexibility. It is reported that these training programs can reduce the incidence of knee injuries by up to 27% and ACL injuries by up to 51%. Screening, identification, and correction of endangering movement patterns like the dynamic valgus are the first crucial steps in order to prevent knee and ACL injuries in athletes. Furthermore, jumping, running and flexibility exercises as well as balance and strength training are proven to reduce the incidence of these injuries and should, therefore, be integrated into the regular warm up program. Appropriate complete prevention programs are freely accessible via the Internet and should be adapted to the specific sport disciplines.

Effects of Sex and Fatigue on Biomechanical Measures During the Drop-Jump Task in Children.

Background:Female athletes have a higher rate of anterior cruciate ligament (ACL) injury than males from adolescence and into maturity, which is suggested to result from sex-specific changes in dynamic movement patterns with maturation. Few studies have studied movement strategies and response to fatigue in children.Purpose:To evaluate the effect of fatigue on biomechanical variables associated with increased risk for ACL injury during a drop-jump (DJ) performance in children.Study Design:Controlled laboratory study.Methods:A total of 116 children (mean age, 10.4 years) were recruited from local sports clubs and performed 5 repetitions of a DJ task before and after a fatigue protocol. Kinematic and kinetic data from initial contact (IC) to the first peak vertical ground reaction force (vGRF) were analyzed for both limbs, including limb and fatigue as within-subject factors for analyses between boys and girls. Pearson correlation coefficients were calculated to identify associations between variables of interest.Results:Girls demonstrated greater peak vGRF values than boys (by 8.1%; P < .05), there were greater peak vGRF values for the right limb than the left (by 6.2%; P < .001), and fatigue led to slightly greater values (P < .05). Although weak, the correlation between peak vGRF values and knee flexion excursion was stronger for girls (r = –0.20) than boys (r = –0.08) (P < .006). Fatigue resulted in greater knee flexion angles at IC and less excursion during landing, more so for girls (by 6.1° vs 1.4°; interaction, P < .001), although the knee flexion moment was generally lowered by fatigue (P < .001). Limb asymmetry in knee flexion moments was more pronounced for boys than for girls (interaction, P < .05), contrary to that seen in frontal plane knee moments, where asymmetry was much greater in girls than boys (interaction, P < .001).Conclusion:Even as young athletes, girls and boys seem to adopt dissimilar movement strategies and are differently affected by fatigue.Clinical Relevance:Injury prevention programs should be considered at an earlier age in an effort to lower the risk of ACL injury in athletes.

Hip Muscle Strength Predicts Noncontact Anterior Cruciate Ligament Injury in Male and Female Athletes

Background: Prospective studies have reported that abnormal movement patterns at the trunk, hip, and knee are associated with noncontact anterior cruciate ligament (ACL) injuries. Impaired hip strength may underlie these abnormal movement patterns, suggesting that diminished hip strength may increase the risk of noncontact ACL injury. Purpose: To determine whether baseline hip strength predicts future noncontact ACL injury in athletes. Study Design: Case-control study; Level of evidence, 3. Methods: Before the start of the competitive season, isometric hip strength (external rotation and abduction) was measured bilaterally by use of a handheld dynamometer in 501 competitive athletes (138 female and 363 male athletes) participating in various sports. During the sport season, ACL injury status was recorded, and injured athletes were further classified based on the mechanism of injury (noncontact vs contact). After the season, logistic regression was used to determine whether baseline hip strength predicted future noncontact ACL injury. Receiver operating characteristic (ROC) curves were constructed independently for each strength measure to determine the clinical cutoff value between a high-risk and low-risk outcome. Results: A total of 15 noncontact ACL injuries were confirmed (6 females, 9 males), for an overall annual incidence of 3.0% (2.5% for males, 4.3% for females). Baseline hip strength measures (external rotation and abduction) were significantly lower in injured athletes compared with noninjured athletes (P = .003 and P < .001, respectively). Separate logistic regression models indicated that impaired hip strength increased future injury risk (external rotation: odds ratio [OR] = 1.23 [95% CI, 1.08-1.39], P = .001; abduction: OR = 1.12 [95% CI, 1.05-1.20], P = .001). Clinical cutoffs to define high risk were established as external rotation strength ≤20.3% BW (percentage of body weight) or abduction strength ≤35.4% BW. Conclusion: Measures of preseason isometric hip abduction and external rotation strength independently predicted future noncontact ACL injury status in competitive athletes. The study data suggest that screening procedures to assess ACL injury risk should include an assessment of isometric hip abduction and/or external rotation strength.

Effectiveness of Proprioceptive Training in Grade-II Acute Anterior Cruciate Ligament Injury in Athletes

Objectives: To design rehabilitation program that can improve proprioception in patient with grade-II anterior cruciate ligament (ACL) injury. Methods: 30 subjects fulfilling the inclusion criteria were recruited. Subjects were randomly distributed into standard non-operative ACL injury rehabilitation group (control group, n = 15) and proprioceptive training group (experimental group, n = 15). Standing balance was assessed by single leg stance and time HOP test. Control group subjects were given knee rehabilitation program like strengthening exercise, flexibility exercise while experimental group were given knee rehabilitation along with proprioception training on wobble board. Subjects completed 12 training sessions, each approximately 30 minutes for the duration of three weeks (4 sessions a week). Results: The results show that the experimental group significantly improved with (P < 0.05) than control group. Conclusions: The study shows that impaired proprioceptive are improved by giving training on wobble board in grade-II ACL injury in athletes. Keywords: Acute Anterior Cruciate Ligament, Proprioception, Single Leg Stance Test, Time HOP Test

Effectiveness of Proprioceptive Training in Grade-II Acute Anterior Cruciate Ligament Injury in Athletes

Objectives: To design rehabilitation program that can improve proprioception in patient with grade-II anterior cruciate ligament (ACL) injury. Methods: 30 subjects fulfilling the inclusion criteria were recruited. Subjects were randomly distributed into standard non-operative ACL injury rehabilitation group (control group, n = 15) and proprioceptive training group (experimental group, n = 15). Standing balance was assessed by single leg stance and time HOP test. Control group subjects were given knee rehabilitation program like strengthening exercise, flexibility exercise while experimental group were given knee rehabilitation along with proprioception training on wobble board. Subjects completed 12 training sessions, each approximately 30 minutes for the duration of three weeks (4 sessions a week). Results: The results show that the experimental group significantly improved with (P < 0.05) than control group. Conclusions: The study shows that impaired proprioceptive are improved by giving training on wobble board in grade-II ACL injury in athletes. Keywords: Acute Anterior Cruciate Ligament, Proprioception, Single Leg Stance Test, Time HOP Test

Incidence of Second ACL Injuries 2 Years After Primary ACL Reconstruction and Return to Sport

Background: The incidence of second anterior cruciate ligament (ACL) injuries in the first 12 months after ACL reconstruction (ACLR) and return to sport (RTS) in a young, active population has been reported to be 15 times greater than that in a previously uninjured cohort. There are no reported estimates of whether this high relative rate of injury continues beyond the first year after RTS and ACLR. Hypothesis: The incidence rate of a subsequent ACL injury in the 2 years after ACLR and RTS would be less than the incidence rate reported within the first 12 months after RTS but greater than the ACL injury incidence rate in an uninjured cohort of young athletes. Study Design: Cohort study; Level of evidence, 2. Methods: Seventy-eight patients (mean age, 17.1 ± 3.1 years) who underwent ACLR and were ready to return to a pivoting/cutting sport and 47 controls (mean age, 17.2 ± 2.6 years) who also participated in pivoting/cutting sports were prospectively enrolled. Each participant was followed for injury and athlete exposure (AE) data for a 24-month period after RTS. Twenty-three ACLR and 4 control participants suffered an ACL injury during this time. Incidence rate ratios (IRRs) were calculated to compare the rates (per 1000 AEs) of ACL injury in athletes in the ACLR and control groups. For the ACLR group, similar comparisons were conducted for side of injury by sex. Results: The overall incidence rate of a second ACL injury within 24 months after ACLR and RTS (1.39/1000 AEs) was nearly 6 times greater (IRR, 5.71; 95% CI, 2.0-22.7; P = .0003) than that in healthy control participants (0.24/1000 AEs). The rate of injury within 24 months of RTS for female athletes in the ACLR group was almost 5 times greater (IRR, 4.51; 95% CI, 1.5-18.2; P = .0004) than that for female controls. Although only a trend was observed, female patients within the ACLR group were twice as likely (IRR, 2.43; 95% CI, 0.8-8.6) to suffer a contralateral injury (1.13/1000 AEs) than an ipsilateral injury (0.47/1000 AEs). Overall, 29.5% of athletes suffered a second ACL injury within 24 months of RTS, with 20.5% sustaining a contralateral injury and 9.0% incurring a retear injury of the ipsilateral graft. There was a trend toward a higher proportion of female participants (23.7%) who suffered a contralateral injury compared with male participants (10.5%) (P = .18). Conversely, for ipsilateral injuries, the incidence proportion between female (8.5%) and male (10.5%) participants was similar. Conclusion: These data support the hypothesis that in the 24 months after ACLR and RTS, patients are at a greater risk to suffer a subsequent ACL injury compared with young athletes without a history of ACL injuries. In addition, the contralateral limb of female patients appears at greatest risk.

ACL Reconstruction in Athletes

What are the most common causes of anterior cruciate ligament (ACL) injury in athletes? The most common causes for ACL injury in athletes are noncontact, twisting injuries that involved a pivoting motion. For example, in sports such as soccer, athletes frequently perform motions that plant and twist the lower extremities, putting those who play soccer at one of the highest likelihoods of ACL injuries. Less common mechanisms for ACL tears are contact injuries. Players are often hit from the lateral aspect of the knee, resulting in injuries not only to the ACL, but also to the medial collateral ligament and other ligaments.

Incidence of Second Anterior Cruciate Ligament (ACL) Injury 2 Years after Primary ACL Reconstruction and Return to Sport

Objectives:The incidence of second anterior cruciate ligament (ACL) injury in the first 12 months after ACL reconstruction (ACLR) and return to sport in a young, active population has been reported to be 15 times greater than a previously uninjured cohort. It is unknown if this high relative rate of injury continues beyond the first year after return to sport following ACLR. The tested hypothesis was that the incidence rate of a subsequent ACL injury in the 2 years following ACLR and return to sports would be less than the incidence rate reported within the first 12 months after return to sport, but greater than the ACL injury incidence rate in an uninjured cohort of young athletes.Methods:Seventy-eight subjects who underwent ACLR and were ready to return to a pivoting/cutting sport (RTS) and 47 controls were prospectively enrolled. Each subject was followed for injury and athletic exposure (AE) data for a 24-month period after return to sport. Twenty-three subjects after ACLR and 4 control subjects suffered an ACL injury during this time. Incidence rate ratios (IRR) were calculated to compare the rates (per 1000 athletic exposures [AEs]) of ACL injury in athletes in the ACLR group and control group. For the ACLR group, similar comparisons were conducted for side of injury by sex.Results:The overall incidence rate of a second ACL injury within 24 months after ACLR and RTS (1.39/1000 AE) was nearly 6 times greater (IRR=5.71, 95% CI: 2.0, 22.7, p=0.0003) than healthy control subjects (0.24/1,000 AE). Female ACLR athletes demonstrated 4 times greater rate of injury within 24 months of RTS (IRR=4.51; 95% CI: 1.5-18.2, p=0.0004) than female controls. Within the ACLR group, there was a trend for female subjects to be over two (RR=2.43, 95% CI: 0.8, 8.6) times more likely to suffer a contralateral injury (1.13/1000 AEs) than an ipsilateral injury (0.47/1000 AEs). Overall, 29.5% of athletes suffered a second ACL injury within 24 months of RTS with 20.5% sustaining a contralateral injury and 9.0% incurring an ipsilateral graft re-tear injury. A higher proportion of females (23.7%) suffered a contralateral injury compared to males (10.5%). Conversely, for ipsilateral injuries, the incidence proportion between females (8.5%) and males (10.5%) were found to be similar.Conclusion:These data support the hypothesis that in the 24 months following ACLR and RTS, patients are at greater risk (nearly 6 times) to suffer a subsequent ACL injury compared to young athletes without a history of ACL injury. Additionally, the contralateral limb of female patients appears to be at greatest risk. These 24 month outcome data, analyzed in conjunction with recent 12 month outcome data which noted a 15 times greater risk of ACL injury compared to healthy control subject, indicate that the greatest risk of second ACL injury after ACLR occurs during the initial 12 months after ACLR and RTS than the second year after RTS.

The Effectiveness of Injury-Prevention Programs in Reducing the Incidence of Anterior Cruciate Ligament Sprains in Adolescent Athletes

There is a high incidence of anterior cruciate ligament (ACL) injury in adolescents participating in pivoting sports such as soccer, basketball, and handball. Most ACL injuries in athletes are noncontact injuries, with a mechanism of sudden deceleration, change in direction, or landing from a jump. These mechanisms coupled with an increase in contraction of the quadriceps have been shown as risk factors for ACL injuries. Injuries to the ACL may require surgery, a long rehabilitation, and the potential for reinjury. Studies have shown reductions in lower extremity injury rates using training protocols that focus on landing mechanics, balance training, strength training, and/or agility training. There has been some thought that starting preventive training programs with adolescent athletes may be the most effective approach to reducing adolescent ACL injuries. Can lower extremity injury-prevention programs effectively reduce ACL injury rates in adolescent athletes?

Play at Your Own Risk: Sport, the Injury Epidemic, and ACL Injury Prevention in Female Athletes

This article focuses on describing anterior cruciate ligament (ACL) injury in athletes and the efficacy of implementing a neuromuscular and proprioceptive sports-specific training program to reduce the incidence of ACL ligament injuries. This article will discuss the role of the ACL, epidemiology and etiology, and the four categorical risk factors for incurring an ACL injury: anatomical, environmental, hormonal, and biomechanical. In addition, this article will discuss the mechanisms ACL injuries, as well as a comprehensive review of all of the literature that has been published with regard to the prevention or reduction of ACL injury. The article concludes that a neuromuscular training program might have a direct benefit in decreasing the number of ACL injuries in athletes.

Is there evidence that proprioception or balance training can prevent anterior cruciate ligament (ACL) injuries in athletes without previous ACL injury?

The purpose of “Evidence in Practice” is to illustrate how evidence is gathered and used to guide clinical decision making. This article is not a case report. The examination, evaluation, and intervention sections are purposely abbreviated. A collegiate-level soccer player was instructed by her coach to incorporate a proprioceptive component into her training program. He suggested that she purchase a balance board and immediately begin a program that he designed. She approached her physical therapist (SJF) for more information. I immediately recognized that, because of her sex and sport of choice, she would be at high risk for an anterior cruciate ligament (ACL) injury. Hewett et al1 estimated that as many as 2,200 ACL ruptures per year occur in female collegiate athletes in both the recreational and competitive ranks. Treatment and rehabilitation costs are estimated at $17,000 per ACL injury, which do not take into account the potential loss of long-term participation, loss of scholarship funding, and future disability from arthritic changes in a reconstructed knee.1 For these reasons, a shift toward injury prevention is warranted. Injury prevention for the ACL can take many forms, including a variety of training protocols, athlete education, and bracing. Current studies focus on neuromuscular training as a preventive measure, with programs that include strength, flexibility, plyometrics, sport-specific agility drills, speed enhancement, balance, and athlete education.1–7 A clinician who understands the individual components of these programs could optimize injury prevention and aid athletes in appropriate program design and equipment purchases. In the case of this athlete, my colleagues and I focused on the use of proprioception or balance training and its effect on incidence of ACL injury. We searched the literature to answer our clinical question “Is there evidence that proprioception or balance training can prevent ACL injuries in athletes …