Anterior Cruciate Ligament Injury Rates Research Articles

Influence of the Menstrual Cycle and Training on the Performance of a Perturbed Single-Leg Squatting Task in Female Collegiate Athletes.

Anterior cruciate ligament (ACL) injuries often occur when an athlete experiences an unexpected disruption, or perturbation, during sports. ACL injury rates may also be influenced by the menstrual cycle. To determine whether training adaptations to knee control and muscle activity during a perturbed single-leg squatting (SLS) task depend on menstrual cycle phase in female athletes. Controlled laboratory study. A total of 21 healthy female collegiate athletes (current or former [<3 years]) who competed in 9 different sports performed an SLS task in which they attempted to match their knee position (user signal) to a target signal. The protocol consisted of a 9-condition pretest, 5 sets of 3 training trials, and a 9-condition posttest. One perturbation was delivered in each condition by altering the resistance of the device. Sagittal knee control (absolute error between the target signal and user signal) was assessed using a potentiometer. Muscle activity during perturbed squat cycles was normalized to maximal activation and to corresponding muscle activity during unperturbed squat cycles (%unperturbed) within the same test condition. Athletes performed the protocol during a distinct menstrual cycle phase (early follicular [EF], late follicular [LF], midluteal [ML]). Two-way mixed analysis of variance was used to determine the effects of the menstrual cycle and training on knee control and muscle activity during task performance. Venous blood was collected for hormonal analysis, and a series of health questionnaires and anthropometric measures were also assessed to determine differences among the menstrual cycle groups. After training, athletes demonstrated better knee control during the perturbed squat cycles (lower absolute error, P < .001) and greater soleus feedback responses to the perturbation (%unperturbed, P = .035). Better knee control was demonstrated in the ML phase versus the EF phase during unperturbed and perturbed squat cycles (P < .039 for both). Quadriceps activation was greater in the ML phase compared with the EF and LF phases, both immediately before and after the perturbation (P < .001 for all). Athletes learned to improve knee control during the perturbed performance regardless of menstrual cycle phase. The best knee control and greatest quadriceps activation during the perturbed squatting task was found in the ML phase. These findings may correspond to a lower incidence of ACL injury in the luteal phase and alterations in exercise performance across the menstrual cycle.

Soccer and volleyball players do not land differently: implications for anterior cruciate ligament injury risk.

Non-contact anterior cruciate ligament injuries are common in soccer and volleyball, occurring during changes of direction and landings. This study aimed to investigate kinematic differences between soccer and volleyball players in single-planar and multiplanar landing tasks, simulating sport-specific injury mechanisms. Since the anterior cruciate ligament injury rate in soccer is higher than in volleyball, we hypothesized that volleyball players would adopt safer landing strategies, especially in single-planar landing tasks. Twenty-two soccer and 19 volleyball players performed single-leg drop landing, drop jump in vertical, 45°-medial and 45°-lateral directions. Box height and jump length were adapted to the subject's height and performance level, respectively. A 9-camera motion capture system provided lower limb kinematics. Two mixed multivariate analyses of covariance (sport, task, sex as covariate) were used to compare soccer and volleyball players' initial contact and peak kinematics (α=0.05). Task had significant effects on lower limb initial contact and peak angles, as expected. Sport and task × sport interaction had no significant effects on kinematics. Soccer and volleyball players' landing strategies were thus similar in each task, in opposition to initial hypotheses. We might speculate that the higher anterior cruciate ligament injury rate in soccer may be more related to non-predictable factors than the isolated landing kinematics.

Customized Landing Task for ACL Injury Risk Assessment: Kinematic Sex-Related Differences.

Women present a higher anterior cruciate ligament (ACL) injury rate than men, suggesting sex-related biomechanical differences. Task characteristics are often fixed for both sexes, possibly affecting the perceived difficulty. We investigated kinematic sex differences across landing tasks for ACL injury risk assessment, adjusted to participants' anthropometrics/performance, and whether different tasks affect kinematic sex comparisons. Female subjects would exhibit motion patterns more associated with ACL injury risk, and sex-related differences may depend on task type. Descriptive laboratory study. Level 3. A total of 27 female and 29 male amateur players (18-30 years) executed horizontal hop, drop jump (DJ), and DJ followed by vertical or forward jump (length, proportional to maximal forward jump; box, 20% participant's height). An optoelectronic system provided lower limb kinematics at initial contact and peaks until maximum knee flexion (KF), analyzed separately by multivariate analysis of variance (MANOVA) (α = 0.05). At initial contact, the interaction term had significant effects on hip adduction (P < 0.01) and knee abduction (KAb) (P = 0.04); female participants demonstrated higher KAb (P < 0.01) and knee internal rotation (P = 0.05). For peaks analysis, the interaction term had no significant effects on any individual variable, although significant in MANOVA; female participants had higher KAb (P = 0.01) and lower KF (P = 0.04). Task type affected hip flexion and knee angles in both analyses. All variables in which significant sex-related differences were found are potential ACL injury risk factors, and all findings indicate that the analyzed female sample exhibited higher injury-related patterns. Although customized, male and female participants showed different landing strategies depending on the task. The findings underline how female participants adopted potentially harmful kinematics while executing customized landing tasks (adjusted by subject's anthropometrics/performance), which may enhance risk of ACL injury.

Anterior cruciate ligament injuries in elite ski jumping reliably allow return to competition but severely affect future top performance.

In recent years, anterior cruciate ligament (ACL) injuries have been frequently observed in ski jumping. However, available data in this discipline are very scarce. Therefore, the purpose of this study was to investigate whether an ACL injury in elite-level ski jumping limits the performance level after ACL reconstruction (ACLR). Both male and female elite-level ski jumpers from fivenational A-teams who suffered an ACL injury were identified retrospectively by searching available media reports and Fédération Internationale de Ski (FIS) database. World Cup (WC) results and time-out-of-competition before ACL injury and after ACLR were compared. Only athletes who suffered the injury during or after the 2009-2010 season and who participated in at least one WC competition before the injury were included in this study. The level of athletes' performance from two full seasons before until three seasons after the injury was compared. Eighteen elite-level ski jumpers (11 males/seven females) were eligible for the study. All male and fourfemale athletes returned to professional competition after ACLR. One female athlete ended her career due to prolonged recovery and twohave not yet recovered due to a recent injury. The mean return-to-competition (RTC) time was 14.6 months in males and 13.5 months in females. The mean WC placement decreased after the ACL injury: two seasons before injury the mean position was 17.9 ± 11.0 (n = 12), one season before it was 22.4 ± 12.8 (n = 15). After recovery, the mean placement in seasons 1-3 was: 26.4 ± 8.9 (n = 7), 25.7 ± 10.3 (n = 13), 33.6 ± 12.2 (n = 10) (p = 0.008). Among the athletes returning to competition, only sixmales and threefemales reached their preinjury level and only one male and one female (compared to seven males and three females preinjury) reached an individual top-3 placement after ACLR, accounting for less than 10% of podiums compared to preinjury. Only 60% of the professional ski jumpers reached the preinjury level and less than 15% reached a top-3 placement after the ACL injury. These results support the fact that ACL tear during a ski jumping career may be a significant factor limiting high-level performance. In terms of clinical relevance, the findings implicate the need to analyse the reasons of these very low rates of return to elite-level performance, to analyse ACL injury and RTC rates at lower levels of performance and to develop specific prevention strategies in order to reduce the number of ACL injuries in this sport. Level IV.

Reduction in re-rupture rates following implementation of return-to-sport testing after anterior cruciate ligament reconstruction in 313 patients with a mean follow-up of 50 months

Objectives:The objective of this study was to assess the mid-term effectiveness of a return to sport (RTS) test in relation to preventing anterior cruciate ligament (ACL) re-rupture and contralateral ACL injury following ACL reconstruction (ACLR). Furthermore, this study aimed to assess the timing of passing a, RTS-test after surgery, and the effect age has on RTS outcomes. Methods:Patients undergoing ACLR between August 2014 and December 2018 took an RTS-test following rehabilitation. The RTS-test consisted of the Anterior Cruciate Ligament Return to Sport After Injury Scale, a single-leg hop, a single-leg triple hop, a single-leg triple cross-over hop, a box-drop vertical jump down, a single-leg 4-rep max-incline leg press, and a modified agility T test. RTS-passing criteria were ≥90% limb symmetry index in addition to defined takeoff and landing parameters. Mid-term review assessed sporting level, ACL re-injury, and contralateral ACL injury. ResultsA total of 352 patients underwent RTS-testing, following ACLR with 313 (89%) contactable at follow-up, a mean of 50 months (standard deviation: 11.41, range: 28–76) after surgery. The re-rupture rate was 6.6% after passing the RTS-test and 10.3% following failure (p ​= ​0.24), representing a 36% reduction. Contralateral ACL injury rate after surgery was 6% and was 19% lower in those passing the RTS test. The mean age of patients passing their first RTS-test was significantly higher than that of those who failed (p ​= ​0.0027). Re-ruptures in those who passed the RTS test first time occurred late (>34 months), compared to those who failed first time, which all occurred early (<33 months) (p ​= ​0.0015). The mean age of re-rupture was significantly less than those who did not sustain a re-rupture (p ​= ​0.025). Conclusion:Passing a RTS-test following ACLR reduces ACL re-rupture by 36.21% and contralateral ACL injury by 19.15% at mid-term follow-up. Younger patients are more likely to fail a RTS-test and are at higher risk of contralateral ACL rupture.Level III Evidence.

What it takes to have a high-grade pivot shift-focus on bony morphology.

Variations in femoral and tibial bony morphology have been associated with higher clinical grading and increased quantitative tibial translation, but not tibial acceleration, during the pivot shift test following anterior cruciate ligament (ACL) injury. The purpose of this study was to determine the impact of femoral and tibial bony morphology, including a measurement influenced by both parameters (the Lateral Tibiofemoral Articular Distance (LTAD)), on the degree of quantitative tibial acceleration during the pivot shift test and rates of future ACL injury. All patients who underwent primary ACL reconstruction from 2014 to 2019 by a senior orthopedic surgeon with available quantitative tibial acceleration data were retrospectively reviewed. All patients underwent a pivot shift examination under anesthesia with a triaxial accelerometer. Measurements of femoral and tibial bony morphology were performed by two fellowship-trained orthopedic surgeons using preoperative magnetic resonance imaging and lateral radiographs. Fifty-one patients were included at a mean follow-up of 4.4years. The mean quantitative tibial acceleration during the pivot shift was 13.8m/s2 (range: 4.9-52.0m/s2). A larger Posterior Condylar Offset Ratio (r = 0.30, p = 0.045), smaller medial-to-lateral width of the medial tibial plateau (r = -0.29, p = 0.041), lateral tibial plateau (r = -0.28, p = 0.042), and lateral femoral condyle (r = -0.29, p = 0.037), and a decreased LTAD (r = -0.53, p < 0.001) significantly correlated with increased tibial acceleration during the pivot shift. Linear regression analysis demonstrated an increase in tibial acceleration of 1.24m/s2 for every 1mm decrease in LTAD. Nine patients (17.6%) sustained ipsilateral graft rupture and 10 patients (19.6%) sustained contralateral ACL rupture. No morphologic measurements were associated with rates of future ACL injury. Increased convexity and smaller bony morphology of the lateral femur and tibia were significantly associated with increased tibial acceleration during the pivot shift. Additionally, a measurement, termed the LTAD, was found to have the strongest association with increased tibial acceleration. Based on the results of this study, surgeons can utilize these measurements to preoperatively identify patients at risk of increased rotatory knee instability. Level IV.

Incidence of anterior cruciate ligament injury patterns in Japanese judo players from a nationwide insurance database

ObjectiveThis study aimed to characterize the age- and sex-specific Anterior cruciate ligament (ACL) injury rates and related injury patterns in judo players in Japan using the nationwide insurance database. MethodsThis was a descriptive epidemiological study. We examined a total of 2142 adolescents with anterior cruciate ligament injuries registered in the insurance system of the Japan Sports Council between January 2009 and December 2018. The age- and sex-specific incidences were estimated for the levels of 7th, 8th, and 9th grades of junior high school and 10th, 11th, and 12th grades of high school. The anterior cruciate ligament injury circumstances were classified into three patterns based on the impact to the involved knee: high-impact valgus force, low-impact trunk displacement, or no-impact knee twisting. ResultsThe incidence of anterior cruciate ligament injury from the 7th to 12th grades were 0.5, 0.9, 0.9, 6.9, 8.6, and 6.1 per 1000 athlete-years in male players and 1.3, 3.8, 3.4, 16.8, 19.5, and 13.6 per 1000 athlete-years in female players. The most prevalent injury pattern was a low-impact contact injury (42.6%) with Osoto-gari, followed by a high-impact contact injury (29.8%). The concomitant medial collateral ligament (MCL) injury rate was 18.1%, which was correlated with a high-impact contact injury (p = 0.005) by multiple regression analysis. ConclusionsThe highest incidence of age- and sex-specific anterior cruciate ligament injury was 19.5 per 1000 athlete-years in female high school students in the 11th grade. The most frequent injury pattern was low-impact contact injury with trunk displacement, indicating that trunk stabilization training could help prevent anterior cruciate ligament injury in judo.

Allograft Anterior Cruciate Ligament Reconstruction Fails at a Greater Rate in Patients Younger Than 34 Years

To characterize the secondary anterior cruciate ligament (ACL) injury rates after primary allograft anterior cruciate ligament reconstruction (ACLR) and to identify the age cut-score at which the risk of allograft failure decreases. All patients who underwent primary ACLR within a single orthopaedic department between January 2005 and April 2020 were contacted at a minimum of 2 years post-ACLR to complete a survey regarding complications experienced post-surgery, activity level, and perceptions of knee health. Patients were excluded for incidence of previous ACLR (ipsilateral or contralateral) and/or age younger than 14 years. Relative proportions were calculated, binary regression analysis was performed, and receiver operating characteristic analysis was used to identify the threshold age for maximal sensitivity and specificity to predict high risk of allograft failure, defined as undergoing revision ACLR. Of the 939 surveys completed, 398 patients underwent primary allograft ACLR (mean age 39.5years; range 16.0-66.1 years; 54.3% female). The secondary ACL injury rate was 11.6% (5.8% ipsilateral revision ACLR, 5.8% contralateral ACL injury). Male and female patients had similar revision (5.5% male, 6.0% female, P= .82) and contralateral ACL injury rates (6.6% male, 5.1% female, P= .52). Receiver operating characteristic analysis indicated that age ≤34 years was threshold for differentiating high risk of allograft failure (area under the curve 0.65, 95% confidence interval 0.55-0.76; P= .014). Patients aged ≤34 years had a greater secondary injury rate than patients >34 years (20.4% (10.2% revision ACLR, 10.2% contralateral ACL injury) versus 6.9% (3.5% revision ACLR, 3.5% contralateral ACL injury; P < .001). Binary regression analysis demonstrated that decreasing age was associated with increased risk of graft failure (χ2= 7.9, P= .02.). Allograft ACLR showed similar failure rates between sexes but displayed suboptimal graft failure outcomes in younger and active patients. By age 34 years, the increased revision risk for younger patients diminished. Level IV, therapeutic case series.

A Diagnosis of Vitamin D Deficiency Is Associated With Increased Rates of Anterior Cruciate Ligament Tears and Reconstruction Failure

To characterize the association between a diagnosis of hypovitaminosis D and primary anterior cruciate ligament (ACL) tear, primary anterior cruciate ligament reconstruction (ACLR), and revision ACLR in different sex and age cohorts. In this retrospective cohort study of the PearlDiver claims database, records were queried between January 1, 2011, and October 31, 2018 for all patients aged 10 to 59 years who received a diagnosis of hypovitaminosis D. Rates of primary ACL tears, primary reconstruction, and revision reconstruction were calculated for sex- and age-specific cohorts and compared with a control of patients without a diagnosis of hypovitaminosis D. Incidence rates for primary ACL injuries were calculated, and multivariable logistic regression was used to compare rates of ACL injury, primary reconstruction, and revision reconstruction while controlling for age, sex, Charlson Comorbidity Index, and several other comorbidities. Among the 328,011 patients (mean age 41.9 ± 12.6 years, 65.8% female) included in both the hypovitaminosis D and control cohorts, the incidence of ACL tears was 115.2 per 100,000 person-years (95% confidence interval [CI] 107.2-123.7) compared with 61.0 (95% CI 55.2-67.2) in the demographic- and comorbidity-matched control cohort. The study cohort was significantly more likely to suffer an ACL tear over a 1- (aOR 1.67, 95% CI 1.41-1.99, P < .001) and 2-year (aOR 1.81, 95% CI 1.59-2.06, P < .001) period. This trend remained for both male patients at the 1- (aOR 1.66, 95% CI 1.29-2.14, P < .001) and 2-year (aOR 1.68, 95% CI 1.37-2.06, P < .001) mark and female patients at the 1- (aOR 1.69, 95% CI 1.33-2.14, P < .001) and 2-year (aOR 1.80, 95% CI 1.51-2.14, P < .001) mark. Finally, patients with vitamin D deficiency had a significantly increased likelihood of undergoing a revision ACLR within 2 years of a primary reconstruction (aOR 1.28, 95% CI 1.05-1.55, P= .012). This study reports an association between patients previously diagnosed with hypovitaminosis D and significantly increased rates of both index ACL tears (81% increase within 2 years of diagnosis) and revision ACLR (28% within 2 years). These results identify a population with increased odds of injury and provide valuable knowledge as we expand our understanding of the relationship between vitamin D and musculoskeletal health. Level III, retrospective database study.

Clinical Outcomes After ACL Reconstruction in Soccer (Football, Futbol) Players: A Systematic Review and Meta-Analysis.

The risk factors for anterior cruciate ligament (ACL) tear for athletes participating in pivoting sports includes young age and female sex. A previous meta-analysis has reported a reinjury rate of 15% after ACL reconstruction (ACLR) for athletes across all sports. To the best of the authors' knowledge, this is the first systematic review and meta-analysis of available literature reporting outcomes after ACLR in soccer players. To review and aggregate soccer-specific outcomes data after ACLR found in current literature to help guide a more tailored discussion regarding expectations and prognosis for soccer players seeking operative management of ACL injuries. A comprehensive search of publications was performed using PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and SPORTDiscus databases. Inclusion criteria consisted of original studies, level of evidence 1 to 4, studies reporting clinical and patient-reported outcomes (PROs) after primary ACLR in soccer players at all follow-up length. The primary outcomes of interest were graft failure/reoperation rates, ACL injury in contralateral knee, return to soccer time, and PROs. Level 4. Search of literature yielded 32 studies for inclusion that involved 3112 soccer players after ACLR. The overall graft failure/reoperation rate ranged between 3.0% and 24.8% (mean follow-up range, 2.3-10 years) and the combined ACL graft failure and contralateral ACL injury rate after initial ACLR was 1.0% to 16.7% (mean follow-up range, 3-10 years); a subgroup analysis for female and male players revealed a secondary ACL injury incidence rate of 27%, 95% CI (22%, 32%) and 10%, 95% CI (6%, 15%), respectively. Soccer players were able to return to play between 6.1 and 11.1 months and the majority of PROs showed favorable scores at medium-term follow-up. Soccer players experience high ACL injury rates after primary ACLR and demonstrated similar reinjury rates as found in previous literature of athletes who participate in high-demand pivoting sports.

Differences in Short-Term Sport-Specific Functional Recovery After Primary ACL Reconstruction in the Adolescent Athlete.

Although anterior cruciate ligament (ACL) injury rates have been studied extensively, it is unclear whether levels of functional and psychological readiness for return-to-sport after primary ACL reconstruction (ACLR) differ based on an athlete's primary sport. Youth athletes in different primary sports will demonstrate differences in short-term functional recovery, as well as patient-reported psychological and functional recovery after primary ACLR. Retrospective cohort study of consecutive patients treated for ACL injury in pediatric sports medicine clinics. Level 3. Patients included underwent primary ACLR between December 1, 2015 and December 31, 2019 and reported sports participation at the time of injury. Demographic data, sports participation, surgical data, functional testing scores (Y-Balance Test [YBT]), functional and psychological patient-reported outcome measures (PROMs), and timing of return-to-play clearance were reviewed. YBT scores were the primary metric for clearance. Four groups were studied: soccer, football, basketball, and other. A total of 220 male and 223 female athletes were included; 65.28% of soccer players were female and 100% of football players were male (P < 0.01). At initial postoperative YBT testing (6-9 months), soccer players had higher operative (P < 0.01) and nonoperative (P < 0.01) leg composite scores when compared with basketball players. No significant differences were found between sports in functional or psychological PROMs at presurgical baseline or 6 months postoperatively. When compared with football, soccer players completed functional clearance in a shorter time from surgery (P = 0.02). Multivariate analysis showed level of competition as a significant independent variable for clearance in female athletes. After primary ACLR, athletes, especially female athletes, demonstrated short-term sport-specific differences in YBT scores. Soccer players attained clearance sooner than football players. Level of competition influenced YBT composite scores in all athletes and time to clearance in female athletes. Sport-specific differences in reinjury should be investigated to determine whether changes in return-to-play evaluation should be implemented.

The incidence rate of ACL injuries and ankle sprains in basketball players: A systematic review and meta-analysis.

To quantify the incidence rate of anterior cruciate ligament (ACL) injuries and ankle sprains according to player sex, playing level, and exposure setting (training vs. games) in basketball players. PubMed, MEDLINE, Google Scholar, and ScienceDirect were searched. Only studies reporting the number of ACL injuries and/or ankle sprains alongside the number of athlete-exposures (training sessions and/or games) in basketball players were included. Thirty studies (17 reporting ACL injuries and 16 reporting ankle sprains) were included in the meta-analysis. Higher (p < 0.05) ACL injury incidence rates per 1000 athlete-exposures were recorded in females (female: 0.20 95% confidence intervals [0.16-0.25]; male: 0.07 [0.05-0.08]; female-to-male ratio: 3.33 [3.10-3.57]), in players competing at higher playing levels (amateur: 0.06 [0.04-0.09]; intermediate: 0.16 [0.13-0.20]; elite: 0.25 [0.14-0.64]), and in games (games: female, 0.27 [0.21-0.32]; male, 0.06 [0.03-0.08]; training: female, 0.03 [0.02-0.05]; male: 0.01 [0.00-0.02]; game-to-training ratio: 7.90 [4.88-12.91]). Higher (p < 0.05) ankle sprain incidence rates per 1000 athlete-exposures were observed in males (female: 0.82 [0.61-1.03]; male: 0.90 [0.61-1.19]; female-to-male ratio: 0.91 [0.83-0.99]), in players competing at higher playing levels (amateur: 0.54 [0.51-0.57]; intermediate: 1.12 [1.00-1.24]; elite: 1.87 [1.29-2.46]), and in games (games: 2.51 [1.85-3.16]; training: 0.80 [0.52-0.80]; game-to-training ratio: 2.77 [2.35-3.26]). According to player sex, ACL injury incidence rate is higher in females, while ankle sprain incidence rate is greater in males. ACL injury and ankle sprain incidence rates are greater in players competing at higher playing levels and during games compared to training.

The incidence of anterior cruciate ligament injury in youth and male soccer athletes: an evaluation of 17,108 players over two consecutive seasons with an age-based sub-analysis.

To evaluate the incidence of anterior cruciate ligament (ACL) injuries in male athletes from professional soccer clubs over two consecutive seasons (2018-2019) with a sub-analysis based on age category: under-13 (U-13), under-15 (U-15), under-17 (U-17), and under-20 (U-20) years. A total of 17,108 young male soccer players were retrospectively reviewed from sixty-three professional clubs in the four highest Brazilian soccer divisions. Data regarding the number of athletes and the number of ACL injuries confirmed by magnetic resonance imaging (MRI) exams in the 2018 and 2019 seasons were collected. Incidence of ACL injury were compared by season, age category (under-13; under-15; under 17; and under-20), demographic region, and club division. Clubs from all regions of Brazil participated in the study. A total of 336 primary ACL injuries were diagnosed over the two seasons (8,167 athletes during the 2018 season and 8,941 athletes during the 2019 season) among all athletes, which corresponds to 2% of the included athletes. There were 11 cases (0.3%) in the under-13, 53 cases (1.3%) in the under-15, 107 cases (2.5%) in the under-17, and 165 cases (3.8%) in the under-20 age category. There was a higher incidence of ACL injury in the older age groups (p < 0.001). A total of 336 ACL injuries were identified in 17,108 youth soccer players from 63 professional clubs with an overall incidence of 2% over 2 seasons of competition. ACL injury rate ranged from 0.3% to 3.8% and was higher in the older and more competitive club divisions. IV.

Does playing surface affect the risk of anterior cruciate ligament injuries in the National Football League? A look at the 2017 - 2021 NFL seasons

ABSTRACT Background Anterior cruciate ligament (ACL) injuries are devastating injuries for athletes. Prior studies have shown increased ACL injury rates on non-natural surfaces versus natural grass in several sports. The purpose of this study is to calculate the prevalence of ACL injuries in the NFL on natural versus non-natural surfaces to determine if there is a significant increase on non-natural surfaces. Methods Accessing publicly available data for NFL seasons beginning with the 2017–2018 season through 2021–2022 seasons, all ACL injuries with publicly available data concerning timing and playing surface were recorded and categorized according to playing surface. Practice injuries or those without an identifiable playing surface were excluded. Incidence rates, defined as ACL ruptures per game, were calculated. ACL injuries were recorded for each playing surface, as well as the combined category of non-natural grass surface. Odds ratio was calculated to compare the risk of ACL rupture on non-natural surfaces vs natural grass. Results During the 2017–2021 NFL seasons, 173 ACL ruptures were identified with known surfaces. Injury rate for non-natural surfaces was 0.134 compared to 0.097 for grass. Injury rate ratio for non-natural vs natural grass surfaces was 1.211, a 21.1% increased risk of ACL injury in the NFL on non-natural surfaces vs natural grass. OR for non-natural surfaces 1.239 (95% CI 0.900–1.704). Based on these findings there is a trend toward increased risk of ACL injury on non natural grass surfaces, however this did not reach statistical significance. Conclusion Numerous published studies show trends toward increasing rates of ACL injuries on non-natural playing surfaces vs natural grass. Based on our findings the difference is not statistically significant, however it does trend toward increased risk of ACL injury with non-natural surfaces. Further studies should be performed with larger sample sizes in order to further determine the risk of non-natural surfaces.

The effects of core stabilization exercises on the neuromuscular function of athletes with ACL reconstruction

Athletes who have undergone anterior cruciate ligament reconstruction (ACLR) often exhibit persistently impaired kinematics and strength. Core stability training appears to be effective for reducing high-risk landing mechanics and preventing primary anterior cruciate ligament (ACL) injuries; however, there have been few attempts to examine their effects in athletes who have undergone ACLR. This study aimed to investigate the effect of eight weeks of simple core stability training on core endurance, hip strength, and knee kinematics in ACLR athletes. Twenty-six male athletes (20–30 years old) with a history of ACL surgery with hamstring tendon autograft were randomly divided into training (n = 13) and control groups (n = 13). The training group performed core stability exercises for eight weeks before starting their team training; the control group did not receive any intervention. Both groups continued their regular team schedule. The core endurance, hip muscle strength, and knee kinematics were assessed by the McGill test, a hand-held dynamometer, and video-taping, respectively. Analysis of covariance test was used for data analysis. The training group showed a significant increase in core endurance, hip abductor and external rotator strength, knee flexion angle, and a significant decrease in the knee valgus angle during single-leg landing in post-training tests compared to their baseline tests (P < 0.05). Our results demonstrated that core stability exercise alters neuromuscular function to a level that is clinically acceptable and statistically significant. Because of the high incidence rate of secondary ACL injury after ACLR, it is recommended that athletes with a history of ACLR benefit from adding core stability exercises to warm-up routines or tertiary prevention programs even after completing post-operative rehabilitation. It is fast and not time-consuming to perform for athletes to reduce the risk factors of re-injury.Trial registration: This study was registered in the Iranian Registry of Clinical Trials with the number IRCT20190224042827N2, registered on 19 December 2019.

HIGHER RETURN TO SPORT WITH PATELLAR TENDON AUTOGRAFT VERSUS HAMSTRING TENDON AUTOGRAFT FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

The bone-patellar tendon-bone (BTB) autograft has a lower rate of graft failure but a higher rate of contralateral anterior cruciate ligament (ACL) injury after primary ACL reconstruction. Subsequent contralateral injury may be a marker of success of the BTB graft, but it is unclear whether the type of graft influences the rate of return to sport. This study aimed to compare the rates of return to weekly sport and return to preinjury activity levels between the BTB and hamstring tendon autografts following primary ACL reconstruction.Prospective data on primary ACL reconstructions recorded in the New Zealand ACL Registry between April 2014-November 2019 were analyzed. The primary outcome was return to weekly sport, defined as a Marx activity score of 8, at 2-year follow-up. The secondary outcome was return to preinjury activity level, defined as a post-operative Marx activity score that was equal or greater to the patient's preinjury Marx score. Return to sport was compared between the BTB and hamstring tendon autografts via multivariate binary logistic regression with adjustment for patient demographics.4259 patients were analyzed, of which 50.3% were playing weekly sport (n = 2144) and 28.4% had returned to their preinjury activity level (n = 1211) at 2-year follow-up. A higher rate of return to weekly sport was observed with the BTB autograft compared to the hamstring tendon autograft (58.7% versus 47.9%, adjusted odds ratio = 1.23, p = 0.009). Furthermore, the BTB autograft had a higher rate of return to preinjury activity levels (31.5% versus 27.5%, adjusted odds ratio = 1.21, p = 0.025).The BTB autograft is associated with a higher return to sport and may explain the higher rate of contralateral ACL injury following primary ACL reconstruction.

Comprehensive inpatient rehabilitation for elite athletes after anterior cruciate ligament reconstruction.

[Purpose] The authors' institute offers a comprehensive inpatient approach to rehabilitation after anterior cruciate ligament reconstruction surgery, providing nutritional and psychological support in addition to exercise and physical therapy. This study aimed to determine the outcomes of athletes undergoing this comprehensive rehabilitation program and to compare the outcomes of bone-patellar tendon-bone and semitendinosus/gracilis autograft recipients. [Participants and Methods] Elite athletes who underwent comprehensive inpatient rehabilitation at the authors' institute for at least two weeks after anterior cruciate ligament reconstruction were mailed a questionnaire. Their recovery levels, which were measured against preinjury performance, and secondary anterior cruciate ligament injury rates, were evaluated and compared according to graft type. [Results] Valid responses from 45 athletes were analyzed (bone-patellar tendon-bone [n=12]; semitendinosus/gracilis [n=33]). The frequency of return to preinjury activity levels and secondary anterior cruciate ligament injury were comparable between bone-patellar tendon-bone and semitendinosus/gracilis graft recipients. A greater proportion of athletes returned to preinjury activity levels, while a lower percentage experienced re-rupture compared to previous studies. [Conclusion] A comprehensive rehabilitative approach after anterior cruciate ligament reconstruction may contribute to improved postoperative performance irrespective of graft type. Objective evaluations are needed in the future to clarify the benefits of specific rehabilitative approaches.

Higher Adherence to Anterior Cruciate Ligament Injury Prevention Programs Is Associated With Lower Injury Rates: A Meta-Analysis and Meta-Regression.

Background: Athletes who participate in sports that involve cutting and pivoting movements are particularly susceptible to anterior cruciate ligament (ACL) injury. Preventing this injury is the best way to combat its health consequences and costs. There may be a dose-response relationship between adherence and injury reduction. Purpose: We sought to examine whether athletes' adherence to injury prevention programs (IPPs) is associated with reductions in ACL and lower extremity (LE) injuries. Methods: We conducted a systematic review of the PubMed, EMBASE, and Cochrane Library databases, searching for studies published between 2011 and 2021. Studies were included if they reported on the use of an ACL IPP compared with a control group and recorded the rate of injuries to calculate a rate ratio, as well as adherence to the program as a percentage of sessions performed. For the meta-analysis, the rate ratios were pooled using the DerSimonian-Laird random-effects model. Results: For the 15 studies included (11 randomized controlled trials and 4 cohort studies), the random-effects model grouped athletes' adherence to an IPP as high (76% or more of the sessions), moderate (51%-75% of the sessions), and low (50% or fewer of the sessions). We found that athletes with the highest level of IPP adherence had a significantly lower incidence of ACL injury. The rate ratios for moderate and low adherence did not demonstrate a reduced incidence of ACL injury. Injury prevention program participation was also associated with a decrease in LE injury rates. Conclusion: This systematic review and meta-analysis found that athletes with high adherence to IPPs had reduced rates of ACL and LE injuries. Our findings suggest that educating coaches and athletes on the dose-dependent benefits of IPPs may promote the routine incorporation of these programs into warm-up sessions to decrease the risk of ACL and LE injuries.

Isometric Knee Strength is Greater in Individuals Who Score Higher on Psychological Readiness to Return to Sport After Primary Anterior Cruciate Ligament Reconstruction.

Anterior cruciate ligament (ACL) injury is extremely common among athletes. Rate of second ACL injury due to surgical graft rupture or contralateral limb ACL injury is approximately 15-32%. Psychological readiness to return to sport (RTS) may be an important predictor of successful RTS outcomes. Psychological readiness can be quantified using the ACL Return to Sport after Injury (ACL-RSI) questionnaire, with higher scores demonstrating greater psychological readiness. The purpose of this study was to investigate differences in functional performance and psychological readiness to return to sport among athletes who have undergone primary ACL reconstruction (ACLR). Descriptive cohort study. Eighteen athletes who had undergone primary ACLR were tested at time of RTS clearance. The cohort was divided into two groups, high score (HS) and low score (LS), based on median ACL-RSI score, and performance on static and dynamic postural stability testing, lower extremity isokinetic and isometric strength testing, and single leg hop testing was compared between the groups using an independent samples t-test. The median ACL-RSI score was 74.17. The average ACL-RSI score was 83.1±6.2 for the HS group and 61.8±8.0 for the LS group. High scorers on the ACL-RSI performed significantly better on isometric knee flexion as measured via handheld dynamometry (22.61% ±6.01 vs.12.12% ±4.88, p=0.001) than the low score group. The findings suggest that increased knee flexion strength may be important for psychological readiness to RTS after primary ACLR. Further research is indicated to explore this relationship, however, a continued emphasis on improving hamstring strength may be appropriate during rehabilitation following ACLR to positively impact psychological readiness for RTS. III.

Repeat Anterior Cruciate Ligament Injury and Return to Sport in Australian Soccer Players After Anterior Cruciate Ligament Reconstruction With Hamstring Tendon Autograft

Background: Soccer is the most commonly played team sport in the world and a high-risk sport for anterior cruciate ligament (ACL) injury and subsequent ACL reconstruction (ACLR). Purpose: To assess the rate of further ACL injury in patients who have undergone ACLR with hamstring tendon autograft after soccer injuries in Australia and to determine factors associated with repeat ACL injury and return to soccer. Study Design: Case-control study; Level of evidence, 3. Methods: From a prospectively collected database, a series of 1000 consecutive ACLRs using hamstring autografts performed in soccer players were identified. Patients were surveyed at a minimum 5 years after reconstruction, including details of further ACL injuries to either knee, return to soccer or other sports, and psychological readiness per the Anterior Cruciate Ligament Return to Sport after Injury (ACL-RSI) scale. Results: Of the 862 participants reviewed, ACL graft rupture occurred in 85 (10%) and contralateral ACL rupture in 68 (8%) within 5 years after the reconstruction. The 5-year ACL graft survivorship was 94% for females and 88% for males. The survivorship of the contralateral ACL was 92% for males and 90% for females. When compared with those aged >25 years, the odds of ACL graft rupture was increased by 4 to 5 times in those aged 19 to 25 years and 3 to 7 times in those ≤18 years. Further ACL injury to the graft or contralateral knee occurred in 44% of males aged ≤18 years. Risk factors for further ACL injury were younger age at time of surgery, male sex, and return to soccer. Graft diameter did not influence ACL graft rupture rates, and 70% of patients returned to soccer after ACLR. The mean ACL-RSI score was 59, and patients who reported more fear of reinjury on this scale were less likely to have returned to soccer. Conclusion: The prevalence of ACL graft rupture (10%) and contralateral ACL rupture (8%) was near equivalent over 5 years in this large cohort of mostly recreational Australian soccer players. ACLR with hamstring autograft is a reliable procedure, allowing 70% of patients to return to soccer in this high-risk population. Risk factors for further ACL injury are progressively younger age at time of surgery, male sex, and return to soccer. Graft diameter was not a factor in ACL graft rupture, indicating that other factors, particularly age, are of primary importance.