Risk Factors For Anterior Cruciate Ligament Injury Research Articles

Kinematics but not kinetics alterations to single-leg drop jump movements following a subject-tailored fatiguing protocol suggest an increased risk of ACL injury

IntroductionNeuromuscular fatigue causes a transient reduction of muscle force, and alters the mechanisms of motor control. Whether these alterations increase the risk of anterior cruciate ligament (ACL) injury is still debated. Here we compare the biomechanics of single-leg drop jumps before and after the execution of a fatiguing exercise, evaluating whether this exercise causes biomechanical alterations typically associated with an increased risk of ACL lesion. The intensity of the fatiguing protocol was tailored to the aerobic capacity of each participant, minimizing potential differential effects due to inter-individual variability in fitness.MethodsTwenty-four healthy male volunteers performed single leg drop jumps, before and after a single-set fatiguing session on a cycle ergometer until exhaustion (cadence: 65–70 revolutions per minute). For each participant, the intensity of the fatiguing exercise was set to 110% of the power achieved at their anaerobic threshold, previously identified by means of a cardiopulmonary exercise test. Joint angles and moments, as well as ground reaction forces (GRF) before and after the fatiguing exercise were compared for both the dominant and the non-dominant leg.ResultsFollowing the fatiguing exercise, the hip joint was more extended (landing: Δ=−2.17°, p = 0.005; propulsion: Δ=−1.83°, p = 0.032) and more abducted (landing: Δ=−0.72°, p = 0.01; propulsion: Δ=−1.12°, p = 0.009). Similarly, the knee joint was more extended at landing (non-dominant leg: Δ=−2.67°, p < 0.001; dominant: Δ=−1.4°, p = 0.023), and more abducted at propulsion (both legs: Δ=−0.99°, p < 0.001) and stabilization (both legs: Δ=−1.71°, p < 0.001) hence increasing knee valgus. Fatigue also caused a significant reduction of vertical GRF upon landing (Δ=−0.21 N/kg, p = 0.003), but not during propulsion. Fatigue did not affect joint moments significantly.ConclusionThe increased hip and knee extension, as well as the increased knee abduction we observed after the execution of the fatiguing exercise have been previously identified as risk factors for ACL injury. These results therefore suggest an increased risk of ACL injury after the execution of the participant-tailored fatiguing protocol proposed here. However, the reduced vertical GRF upon landing and the preservation of joint moments are intriguing, as they may suggest the adoption of protective strategies in the fatigued condition to be evaluated in future studied.

Gender differences in the impact of anatomical factors on non-contact anterior cruciate ligament injuries: a magnetic resonance study

PurposeTo identify MRI-detected anatomical risk factors for non-contact anterior cruciate ligament (ACL) injuries across genders.MethodsA retrospective analysis was performed on 141 ACL-reconstructed patients (35 females, 106 males) and 142 controls (37 females, 105 males) from January 2020 to April 2022. Inclusion criteria were primary non-contact ACL injuries. The tibial plateau slope, lateral femoral condyle index, Insall-Salvati index, and patellar tendon angle were measured, using binary logistic regression for gender-specific risk evaluation.ResultsIncreased lateral tibial plateau slope, reduced intercondylar notch width index, lateral femoral condyle index, and patellar tendon angle correlated with ACL injuries in both genders. The Insall-Salvati index was a significant risk factor in females but not in males.ConclusionThis study identifies the lateral tibial plateau slope, notch width index, lateral femoral condyle index, and patellar tendon angle at near-extension as risk factors for ACL injuries in both genders, with the Insall-Salvati index also implicated in females.

The relationship between lateral femoral condyle ratio measured by MRI and anterior cruciate ligament injury.

Previous studies have shown that the lateral femoral condyle ratio (LFCR) measured by X-ray has a significant relationship with the anterior cruciate ligament (ACL) injury. However, few relevant studies have been performed on LFCR measured by magnetic resonance imaging (MRI). (1) To evaluate the relationship between LFCR measured by MRI and ACL injury or rerupture. (2) To compare the LFCR measured by MRI with existing bony morphological risk factors and screen out the most predictive risk factors for primary ACL injury or rerupture. Cohort study; Level of evidence, 3. Totally 147 patients who underwent knee arthroscopic surgery from 2015 to 2019 with minimum follow-up of 48months were retrospectively evaluated. Patients were placed into three groups: 1) the control group of patients with simple meniscus tears without ligament injury; 2) the primary noncontact ACL injury group; 3) ACL rerupture group (ACL reconstruction failure). The LFCR measured by MRI and other previous known risk factors associated with MRI (notch width index, medial tibial slope, lateral tibial slope, medial tibial depth, lateral tibial height) were performed to evaluate their predictive value for ACL injury and rerupture. All the risk factors with p < 0.01 according to univariate analysis were included in the logistic regression models. Receiver operating characteristic (ROC) curves were analyzed for sensitivity, specificity, cut-off, and area under the curve (AUC). Z tests were used to compare the AUC values. The LFCR measured by MRI was obviously higher in primary ACL injury group (0.628 ± 0.020) and in ACL rerupture group (0.625 ± 0.021) than that in the control group (0.593 ± 0.030). The best risk factor was the LFCR with a cut-off of 0.602 (AUC, 0.818; 95% CI, 0.748-0.878; sensitivity, 90%; specificity, 66%). When combined with lateral tibial slope (cutoff, 7°) and lateral tibial height (cutoff, 3.6mm), the diagnostic performance was improved significantly (AUC, 0.896; 95% CI, 0.890-0.950; sensitivity, 87%; specificity, 80%). The increased LFCR measured by MRI was associated with a significantly higher risk for ACL injury or rerupture. The combination of LFCR, lateral tibial slope and lateral tibial height were the most predictive risk factors. This may help clinicians identify susceptible individuals and allow precision approaches for better prevention, treatment and management of this disease.

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.

Decreased sagittal slope of the medial tibial spine and deep concavity of the lateral tibial spine are risk factors for noncontact anterior cruciate ligament injury.

This study aimed to assess the relationship between the geometric features of tibial eminence and susceptibility to noncontact anterior cruciate ligament (ACL) injuries. Patients with unilateral noncontact knee injuries between 2015 and 2021 were consecutively enroled in this study. Based on knee magnetic resonance imaging (MRI) and arthroscopic visualisation, patients were categorised into the case group (ACL rupture) and control group (ACL intact). Using MRI, the geometric features of tibial eminence were characterised by measuring the sagittal slopes, depth of concavityand coronal slopes of the inclined surfaces of the tibial spines. Univariate and multivariate logistic regressions were conducted to explore independent associations between quantified geometric indices of tibial eminence and the risk of noncontact ACL injuries. This study included 187 cases and 199 controls. A decreased sagittal slope of the medial tibial spine (MTSSS) (combined group: odds ratio [OR]: 0.87 [0.82, 0.92], p < 0.001; females: OR: 0.88 [0.80, 0.98], p = 0.020; males: OR: 0.87 [0.81, 0.93], p < 0.001) and an increased depth of concavity in the lateral tibial spine (LTSD)(combined group: OR: 1.51 [1.24, 1.85], p < 0.001; females: OR: 1.65 [1.12, 2.43], p = 0.012; males: OR: 1.44 [1.11, 1.89], p = 0.007) were independent risk factors for noncontact ACL injuries. Moreover, a steeper coronal slope of the inclined surface of the medial tibial spine was a significant predictor of noncontact ACL injuries for males (MTSCS: OR: 1.04 [1.01, 1.08], p = 0.015) but not for females. Geometric features of tibial eminence, particularly a decreased MTSSS and an increased LTSD, were identified as independent risk factors for noncontact ACL injuries. These findings will help clinicians identify individuals at high risk of ACL injury and facilitate the development of targeted prevention strategies. Level III.

Anterior knee laxity is greater in athletic females who attain menarche at a younger age.

Females with above-average anterior knee laxity values are at increased risk of anterior cruciate ligament (ACL) injury. The purpose of this study was to examine the effects of menarche age (MA) and menarche offset on anterior knee laxity in young, physically active women. Anterior knee laxity (KT-2000) and menstrual characteristics (per self-report) were recorded in 686 Slovenian sportswomen from team handball, volleyball and basketball club sports (average years sport participation: 7.3 ± 3.6 years). Females were stratified into four groups based on their self-reported age at menarche: 9-11, 12, 13 and 14+ years. Anterior knee laxity was compared across MA groups using a univariate analysis of variance (ANOVA) with Bonferroni correction, with and without controlling for factors that could potentially differ between groups and influence anterior knee laxity. Females were then stratified into four groups based on the number of years they were away from their age at onset of menarche. Groups were compared using a univariate ANOVA with Bonferroni correction, with and without controlling for factors that differed between groups and could influence anterior knee laxity. Anterior knee laxity was greater in females who attained menarche at 12 years of age (6.4 ± 1.5 mm) or younger (6.6 ± 1.6 mm) compared to 14 years of age or older (5.8 ± 1.2 mm) (p < 0.001; partial η2 = 0.032). Anterior knee laxity was 0.7-1.4 mm greater in females who were 5 or more years away from menarche compared to those who were within 2 years of menarche (5.8 ± 1.3 mm; p < 0.001). Anterior knee laxity is greater in females who attained menarche at a younger age and in females who are 5 or more years postmenarche. Age of menarche represents a critical pubertal event that is easy for women to recall and may provide important insights into factors that moderate anterior knee laxity, a risk factor for ACL injury in women. Level IV.

Evaluation of hop test movement quality to enhance return to sport testing. A cross-sectional study.

Return to Sport tests with functional hop tests are often used to decide when a person is ready to return to sport after an anterior cruciate ligament (ACL) injury. Poor movement quality, such as knee valgus, hip adduction and hip internal rotation is considered a risk factor for ACL injury. However, it is unclear whether existing tests adequately cover the aspect of movement quality. This study aims to investigate whether there is a relationship between the calculated limb symmetry index (LSI) of hop tests as an indication of performance and the total score of the "Quality First" assessment (movement quality). The second aim is to examine the reliability of the newly developed "Quality First" assessment for evaluating movement quality in hop tests. The cross-sectional study recruited 34 patients with an ACL reconstruction. The vertical hop, single-leg hop for distance, and side hop tests were performed and recorded. The video recordings were assessed using the "Quality First" assessment. The Spearman correlation coefficient was calculated using the LSI and the "Quality First" total score. Intraclass correlation coefficients (ICC) and standard error of measurements (SEM) were used to calculate intra- and interrater reliability. In addition, the minimal detectable change (MDC) was determined. The correlation test between the LSI and the "Quality First" total score showed no correlation for all three jumps (r = -0.1-0.02/p-value = 0.65-0.93). The interrater reliability of the "Quality First" assessment showed fair to good reliability (ICC2: 0.45-0.60), with SEM ranging from 1.46 to 1.73 and the MDC from 4.06 to 4.8. Intrarater reliability was good to excellent (ICC3: 0.73-0.85), with SEM values ranging from 0.89 to 1.09 and the MDC from 2.47 to 3.01. The quality of movement, measured with the "Quality First" assessment, indicated no correlation with the calculated LSI from jump performance, therefore movement quality should also be examined in Return to Sport tests. The "Quality First" assessment shows fair to good reliability when used by different raters. When used multiple times by the same rater, the assessment has good to excellent reliability.

Hereditary Anatomical Risk Factors for Anterior Cruciate Ligament Injuries.

Genetic and anatomical factors have been reported as risk factors for anterior cruciate ligament (ACL) injuries. This study aimed to investigate anatomical characteristics in family members sustaining ACL injuries, compared with age- and sex-matched patients with simple meniscus injuries. Medical records of 1548 patients who underwent ACL reconstruction were reviewed. Cases of ACL injury occurring in first-degree relatives were selected. Forty-one patients from 20 families were included in the study (F-ACL group). Fifty patients with meniscus injuries were included as controls. Anatomical factors comprising posterior-inferior tibial slope (PITS), notch width index (NWI), notch angle (NA), and intercondylar notch roof inclination angle (RA) were compared between groups. The correlation of these anatomical factors between parent and child or siblings was also investigated. The 41 patients (20 families) consisted of 12 parent-child pairs and 29 siblings (13 pairs and one trio). Injuries occurred during playing the same sport in 11 families (55%). PITS was significantly steeper in the F-ACL group (9.9 vs. 7.8 degrees). NWI and NA were significantly smaller in the F-ACL group (0.262 vs. 0.278 and 50.5 vs. 58.8 degrees). RA was significantly greater in the F-ACL group (130 vs. 126.9 degrees). A positive correlation in NA (r = 0.677) and a weak correlation in NWI and RA were observed between family members. Common anatomical risk factors of ACL injury exist within families, including intercondylar notch stenosis and steep posterior tibial slope. The findings suggest the potential for developing effective ACL injury prevention programs targeting these risk factors.

Biomechanical risk factors for ACL injury differ between the sexes when performing a high-intensive exergame

Introduction&#x0D; Incidence rates in anterior cruciate ligament (ACL) injuries, which are linked to multiple factors, are higher in females than males (Sutton &amp; Bullock, 2013). However, the main contributors to the difference in risk are biomechanical factors such as increased knee valgus (KV), knee internal rotation (KIR), or decreased hip flexion (HF; Seyedahmadi et al., 2022). Returning back to sports after an injury requires extensive rehabilitation as well as training of dual-task situations in order to be physically and cognitively prepared. Exergaming represents a dual task including a cognitive and a motor component and may be used as training modality during rehabilitation. It is known that performing a dual-task leads to altered landing movement patterns in healthy athletes (Dai et al., 2018). Before an exergame for rehabilitation after ACL injury can be implemented and tailored to the specific needs of female and male athletes, the movement patterns of males and females need to be understood. Therefore, the aim of this study was to identify biomechanical differences between males and females when performing a high-intensive exergame.&#x0D; Methods&#x0D; Using 3D-motion capture (Vicon) kinematics were measured in 18 healthy athletes (9 male, 9 female) during a 25-min exergame (Sphery Racer, ExerCube). The exergame included nine different exercises of which 8 were used for analysis. The exercises were separated into neutral (squat, jump, burpee) and side-specific exercises (low-touch, mid-touch, high-touch, punch, lunge). For analysis, the maximal KV, maximal KIR, and the minimal HF were extracted during 10-30° knee flexion. These maximal values were then compared between the sexes, the exercises, and both legs with a linear mixed model, for each the neutral and the side-specific exercises.&#x0D; Results&#x0D; A main effect of sex was only found for side-specific exercises in KIR (F(1, 16) = 6.1, p = .02) with females exhibiting higher values. For KV and HF in side-specific exercises as well as all variables in neutral exercises, no significant main effect for sex was found. However, there was a main effect of exercise in KV; KIR, and HF in neutral (p &lt; .001) as well as in side-specific exercises (p &lt; .001).&#x0D; Discussion/Conclusion&#x0D; Differences in KIR between males and females primarily exist during touches and punches. Therefore, exergames should incorporate this fact to counteract increased risk for knee injuries in females.&#x0D; References&#x0D; Dai, B., Cook, R. F., Meyer, E. A., Sciascia, Y., Hinshaw, T. J., Wang, C., &amp; Zhu, Q. (2018). The effect of a secondary cognitive task on landing mechanics and jump performance. Sports Biomechanics, 17(2), 192–205. https://doi.org/10.1080/14763141.2016.1265579&#x0D; Seyedahmadi, M., Minoonejad, H., Karimizadeh Ardakani, M., Heidari, Z., Bayattork, M., &amp; Akbari, H. (2022). What are gender differences in lower limb muscle activity during jump-landing tasks? A systematic review and meta-analysis. BMC Sports Science, Medicine &amp; Rehabilitation, 14(1), Article 77. https://doi.org/10.1186/s13102-022-00469-3&#x0D; Sutton, K. M., &amp; Bullock, J. M. (2013). Anterior cruciate ligament rupture: Differences between males and females. The Journal of the American Academy of Orthopaedic Surgeons, 21(1), 41–50. https://doi.org/10.5435/jaaos-21-01-41

Lower hamstring to quadriceps muscle strength ratio and lower body weight as factors associated with noncontact anterior cruciate ligament injury in male American football players: A prospective cohort study

BackgroundPrevious studies have aimed to determine the use of certain risk factors in predicting the occurrence of noncontact anterior cruciate ligament (ACL) injuries. Unfortunately, evidence regarding noncontact ACL injuries in male American football players is limited. This prospective cohort study aimed to identify intrinsic risk factors for noncontact ACL injury among male American football players. MethodsThis study evaluated 152 male American football players in Japan for potential noncontact ACL injury risk factors during a preseason medical assessment, including anthropometric, joint laxity, and flexibility, muscle flexibility, muscle strength, and balance measurements. A total of 25 variables were examined. Participants were monitored during each season for noncontact ACL injury, as diagnosed by physicians. ResultsNoncontact ACL injuries occurred in 11 knees of 11 players (prevalence; 7.1 %). Injured players were significantly more likely to have lightweight (P = 0.049). No statistically significant between-group differences were found for any other variables. Participants with a lower hamstring to quadriceps (H/Q) ratio (P = 0.04) were more likely to sustain noncontact ACL injuries. ConclusionLower H/Q ratio and lower body weight were significantly associated with new-onset noncontact ACL injury in male American football players. These findings will help develop strategies to prevent noncontact ACL injuries in male American football players.

Does lower extremity alignment during normal stance predict lower limb kinematics and kinetics during drop landings?

BackgroundStatic lower extremity alignment (LEA) during normal stance has been used clinically as a tool to determine the presence of known anterior cruciate ligament (ACL) risk factors during dynamic tasks. Previous work investigating the relationship between static LEA during normal stance and risk factors for ACL injury is limited by the use of imprecise methods or because it focuses on knee valgus only and no other potentially important variables. The aim of this investigation was to determine the relationships between static LEA and the corresponding LEA during drop landings.MethodsForty-one female athletes were recruited for the study (age: 19.8 ± 2.5 years, height: 1.73 ± 0.06 m, mass: 64.03 ± 6.66 kg). Lower limb kinematic data were collected using a 10 camera infrared motion capture system (500 Hz) with retro-reflective markers placed over key anatomical landmarks. This system was linked to two force platforms (1000 Hz) with subsequent three-dimensional kinematic and kinetic data developed using standard software (Visual3D). Following an appropriate warm-up, data collection involved participants standing with their arms partially abducted to record static LEA. This was following by a series of drop landings from a 0.4 m box onto the force platforms. Maximum LEA data during drop landings were then compared with static LEA.ResultsAnalyses showed that in comparison to static stance, during landings the anterior tilt of the pelvis decreased while hip abduction and knee internal rotation increased. At best, static LEA variables were moderately correlated (r = -0.51 to 0.58) with peak values measured during drop landings. Additionally, regression analysis did not yield any significant predictors of any key peak hip or knee variables measured during drop landings (p = 0.15 to 0.89).ConclusionWhen combined, the poor relationships observed between kinematics during static LEA and LEA during drop landings calls into question the practice of using static measures to predict LEA during even simple landing tasks. These findings suggest static assessments of LEA may have minimal value as an ACL injury screening tool.

Better Safe Than Sorry? A Systematic Review with Meta-analysis on Time to Return to Sport After ACL Reconstruction as a Risk Factor for Second ACL Injury.

OBJECTIVE: To compare the time to return to sport (RTS) between patients who did and did not suffer a second anterior cruciate ligament (ACL) injury after ACL reconstruction. DESIGN: Etiology systematic review with meta-analysis. LITERATURE SEARCH: Cochrane Library, Embase, Medline, AMED, and PEDro databases were searched in August 2021 and again in November 2022. STUDY SELECTION CRITERIA: Clinical studies reporting time to RTS after ACL reconstruction and second ACL injury were eligible. DATA SYNTHESIS: We pooled continuous data (time [months] and proportions [%]), with random-effects meta-analyses. Pooled estimates were summarized in forest plots. A qualitative data synthesis was also performed. RESULTS: Twenty-one studies were included in the meta-analysis and 33 in the qualitative synthesis. Pooled incidence of second ACL injury was 16.9% (95% confidence interval [CI]: 12.8, 21.6). Patients who suffered a second ACL injury returned to sport significantly earlier (25 days; 95% CI: 9.5, 40.4) than those who did not suffer another injury. There was no difference in time to RTS for professional athletes who suffered a second ACL injury and those who did not. The certainty of evidence was very low. CONCLUSION: There was very low-certainty evidence that patients who suffered a second ACL injury had returned to sport 25 days earlier than patients who did not have another injury. For professional athletes, there was no difference in time to RTS between athletes who suffered a second ACL injury and athletes who did not. J Orthop Sports Phys Ther 2024;54(3):1-15. Epub 30 November 2023. doi:10.2519/jospt.2023.11977.

Evaluation of a Coach-Centered Youth ACL Injury Risk Reduction Workshop Using RE-AIM Sports Setting Framework

ABSTRACT Introduction/Purpose Our aim was to evaluate the feasibility and short-term effectiveness of a community-based anterior cruciate ligament (ACL) injury risk reduction program (IRP) live workshop using the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework modified for sports settings. Methods We conducted a prospective longitudinal study. Custom surveys were administered before and after the workshop and 1 month later to capture contextual variables needed to evaluate the program using four of the five RE-AIM domains. Live workshops were conducted at community centers throughout the northeastern US, and coaches were trained on risk factors for ACL injuries and how to identify and correct musculoskeletal movements known to increase ACL injury risk. Results Three hundred and seventy-three coaches attended the workshop, but 171 (46.4%; mean age, 33 ± 10 yr; 58% male) completed pre- and post-workshop surveys demonstrating significant improvements (P &lt; 0.0001) in measures of program effectiveness, including knowledge (8.1%), attitudes/beliefs (18.0%), and confidence (39.6%). Overall, 98% of coaches were satisfied with the workshop delivery quality and content. Fifty-three coaches completed a 1-month follow-up survey, 75.5% of whom reported adoption of the ACL IRP. Of these, 100% reported implementing the ACL IRP before practice/training sessions, and 97.5% reported implementing it before games/competitions. Conclusions Overall, the results of this evaluation demonstrate the ACL IRP workshop feasibility and provide guidance for enhancement of the workshop. Our ACL IRP workshop was effective at increasing coaches’ knowledge and perspectives about injury risk reduction principles. Although the behavioral strategies incorporated in the program design promoted high ACL IRP workshop satisfaction, further improvements are needed to increase survey response rates during post-workshop follow-up.

Evaluation of the Anterior Cruciate Ligament Injury Risk During a Jump-Landing Task Using 3-Dimensional Kinematic Analysis Versus the Landing Error Scoring System.

The Landing Error Scoring System (LESS) has been utilized on the field or in the clinic to identify patients with an increased risk for anterior cruciate ligament (ACL) injuries; however, its validity and efficacy have not been fully confirmed. To assess the efficacy of the LESS in identifying the ACL injury risk by examining the correlation between the LESS score and motion patterns on 3-dimensional kinematic analysis. Controlled laboratory study. The jump-landing motion was analyzed for 16 female basketball or badminton players who volunteered to participate in the study. All study participants were aged 19 or 20 years. The sequence of motion was evaluated with the LESS, while kinematic data were simultaneously acquired with a 3-dimensional motion analysis system utilizing the point cluster method. The correlation between the LESS score and knee kinematics was statistically analyzed. When a LESS score ≥6 was defined to be a risk factor for ACL injuries, 7 of the 16 participants (43.8%) were found to exhibit risky motion patterns. Significant correlations were noted between the LESS score and knee valgus (r = 0.87; P < .0001) and internal tibial rotation (r = 0.57; P = .02) at landing. By contrast, a substantial variability was present in knee flexion, showing no correlation with the LESS score. Significant correlations were found between the LESS score and knee valgus and internal tibial rotation during a jump-landing task. The LESS can be regarded as an effective measure to identify risky motion patterns that may increase the likelihood of ACL injuries.

How Subtalar Kinematics Affects Knee Laxity in Soccer Players After Anterior Cruciate Ligament Injury?

Purpose The goal of the current study was to ascertain whether there is an association between foot pronation and anterior cruciate ligament (ACL) injury in a group of elite professional soccer players. Methods Two groups of soccer players were studied, all of whom played in the Greek Super League. The ACL group included players who had suffered an ACL injury in the last 2 years. The non-ACL group was composed of players who had never suffered an ACL injury. We used a 3D baropodometric laser scanner to measure pronation or overpronation (navicular drop phenomenon) of the subtalar joint and how this affects the subtalar joint while standing. We assessed ACL laxity using the Genourob Rotab. Results ACL-injured patients, regardless of the mechanism of injury, exhibited greater navicular drop values than a randomly selected group of subjects with no history of ACL injury. Conclusion Greater knee joint laxity and subtalar pronation may be associated with an increased risk of ACL injury. Pronation of the foot appears to be a risk factor for ACL injury. These findings should be integrated into future studies to better define how neuromuscular control related to lower extremity biomechanics is associated with ACL injury.

Investigating the Role of Proximal Femoral Morphology in Noncontact ACL Injuries: A Comparative Study

Background: Non-contact anterior cruciate ligament (ACL) injury is a common and debilitating injury among athletes, with high recurrence rates and long-term consequences. Identifying individuals at risk of ACL injury can help prevent or reduce the severity of these injuries. The present study aimed to assess the alpha angle (AA) in ACL rupture patients in both the injured (ipsilateral) and non-affected (contralateral) extremities, compared to a control group. Methods and Results: This case-control study included 105 subjects (78.1% male and 21.9% female) aged between 15 and 45 years of both sexes involved in sports. The case group consisted of 54 patients with sport-related, noncontact ACL ruptures identified by MRI. Fifty-one patients, 10(19.6%) of whom were female, with no ACL rupture, were included in the study as a control group. Hip radiographs were taken in all the subjects using the modified Dunn View with the patient in the supine position, hip flexed 45o and abducted 20o. OsiriX software was used to obtain the measurements. Most injuries were caused by football (58.1%), followed by jumping sports (23.8%) and skiing (18.1%). The mean AA was 49.27 o (SD=4.93) for subjects without ACL rupture and 54.84o (SD=6.17) for subjects with ACL rupture, and the difference was statistically significant (P&lt;0.001). Results also showed a statistically significant difference in the AA on the ipsilateral (54.84o [SD=6.17]) and contralateral (49.48o [SD=7.04]) hips of the case subjects (P&lt;0.001). The logistic regression analysis indicated a statistically significant difference in AA between the case and control groups and between hips of the same subject with an OR of 1.12 (P=0.041) and 1.2 (P=0.000), respectively. Conclusion: Alterations in proximal femur morphology should be considered a potential risk factor for ACL injury, and AA can be a significant predictor of ACL injury. We recommend that young athletes actively participating in sports have their hip AA measured so those with higher AA can follow special prevention programs.

Vitamin D deficiency does not associate with anterior cruciate ligament injuries in elite athletes

Objectives: Recently, low levels of Vitamin D levels in sportspersons are observed by many studies. However, the role of low Vitamin D levels on anterior cruciate ligament (ACL) injury is not well studied. The purpose of this study was to find out the correlation between serum Vitamin D levels and ACL injury. Materials and Methods: This is a case–control study in which 55 athletes were enrolled in both cases (ACL deficient) and controls (ACL intact). Serum Vitamin D levels were measured in both the groups (preoperatively and 12 months postoperatively) and depending on the Vitamin D levels, athletes were categorized as Vitamin D deficient (&lt;20 ng/mL), insufficient (20–30 ng/mL), and sufficient (&gt;30 ng/mL). Functional outcomes were assessed using the Lysholm score and Tegner activity score at 12 months follow-up. Results: Overall, 91% of cases and 93% of controls were observed to be Vitamin D deficient or insufficient (n.s.). There was no significant difference among mean Vitamin D levels in cases (16.34 ± 11.89 ng/mL) and controls (18.08 ± 9.9; n.s.). There was no significant difference in post-operative function outcomes (Lysholm score) between the three groups among cases at 12 months follow-up (n.s.). Conclusion: The presence of low Vitamin D levels is not a risk factor for ACL injuries and low Vitamin D levels are not a hindrance to recovery after ACL reconstruction.

Risk Factors for Concomitant Meniscal Injury With Sport-Related Anterior Cruciate Ligament Injury.

Previous studies of concomitant meniscal injury in athletes with anterior cruciate ligament (ACL) injury have examined age, sex, body mass index (BMI), injury mechanism, and time from injury to surgery as potential risk factors. To identify additional risk factors for concomitant meniscal injury, including preinjury joint laxity and lower extremity alignment, in athletes with sport-related ACL injury. Cross-sectional study; Level of evidence, 3. This study included 180 participants aged 13 to 26 years who underwent ACL reconstruction (ACLR) after a first-time ACL injury sustained during participation in sport. Contralateral lower extremity alignment and joint laxity were used as surrogate measures for the injured knee before trauma. Concomitant meniscal tear patterns were identified at the time of ACLR. Sex-specific analyses were conducted. Concomitant meniscal injury was observed in 60.6% of the subjects. The prevalence of concomitant injury was higher in male than female participants (69.9% vs 54.2%; P = .035) due to a higher prevalence of lateral meniscal injuries (56.2% vs 38.3%; P = .018). Among male patients, there was a significant difference in the prevalence of concomitant lateral meniscal tear according to sport participation (≥9 vs <9 h/week: 67.4% vs 35.7%; P = .032). Among male patients, the likelihood of concomitant injury to both the lateral and medial menisci increased by 28.8% for each 1-mm decrease in navicular drop. Among female patients, the likelihood of concomitant injury to the lateral meniscus increased by 15% per degree increase in genu recurvatum and 14% per degree decrease in standing quadriceps angle, with similar effects on the likelihood of concurrent injury to both the lateral and medial menisci. Measures of lower extremity alignment and genu recurvatum previously identified as risk factors for ACL injury were also associated with concomitant meniscal injury in female patients while other risk factors, including BMI and joint laxity, were not. Increased time spent participating in sport and navicular drop were associated with concomitant meniscal injury in male patients.

Poster 272: The Significance Of Posterior Tibial Slope And Rate Of Concomitant Pathology In Pediatric Tibia Spine Avulsion And Anterior Cruciate Ligament Injuries

Objectives: Fractures of the tibial spine (TSF) occur as a result of an anterior cruciate ligament (ACL) avulsion fracture from the proximal tibia. Both TSF and ACL injuries are associated with concomitant intraarticular pathology seen on Magnetic Resonance Imaging (MRI) and intraoperatively. In addition, posterior tibial slope (PTS) has been identified as a potential risk factor for ACL injury. The purpose of this study is to describe concomitant injuries seen on MRI and at time of surgery for TSF and ACL patients, and to characterize posterior tibial slope in patients who sustain these injuries. Our hypothesis is that ACL and TSF injuries have similar rates of meniscal injury, and that posterior tibial slope is increased in patients with TSF and ACL injuries compared to matched controls. Methods: Utilizing an institutional review board approved retrospective study, we identified patients under 18 years of age who underwent arthroscopic management of a TSF from December 31st 2008 to December 31st 2021. Exclusion criteria were patients with a concomitant lower extremity fracture or posterior cruciate ligament injuries, poor imaging quality, and incomplete medical records. TSF patients were compared to an age and gender matched cohort of patients who underwent surgery for a mid- substance ACL rupture, and a similar control group. We evaluated concomitant injuries based on radiology and operative reports and measured PTS on radiographs as well as medial (MTS) and lateral (LTS) posterior slope on MRI for all groups. We compared tibial slope amongst the groups using a one- way analysis of variance test, and the Fisher’s exact test was used to compare concomitant injuries between the ACL and TSF groups. Results: 85 TSF patients met inclusion criteria, of which 44 had an MRI. There were 41 patients in the ACL group and 44 in the control group. The average age was 11.8 years. Concomitant injuries were identified on MRI in 59.1% of TSF and 51.2% of ACL patients, and intraoperatively in 36.5% of TSF and 37% of ACL patients. The most common concomitant injury was lateral meniscus tears. There was no significant differnce between the TSF and ACL groups in terms of lateral meniscus tears seen on MRI (29.5% TSF vs 31.7 ACL, p=1.0) and seen on arthroscopy (18.2% TSF vs 31.7% ACL, p=0.21). Similarly there were no significant differences between the TSF and ACL group in terms of medial meniscus tears seen on MRI (13.6% vs 17.1%, p = 0.77) and on arthroscopy (9% vs 5%, p=0.19). There was a significant difference between groups when comparing the pivot-shift bone bruise pattern seen on MRI (63.6% TSF vs 90.2% ACL, P= &lt;0.01). There was significantly increased radiographic PTS in the TSF and ACL groups (Radiographs 8.7°+/-3.0° TSF vs 9.5°+/-3.3° ACL vs 6.6°+/-2.3° Control, p= &lt;0.01). This was also seen in the MTS mesured on MRI (MTS 5.3°+/-3.1° TSF vs 4.9°+/-2.7° ACL vs 3.7°+/-2.3° Control p= 0.02). There was no significant difference in LTS between TSF and Controls, but there was between ACL and Controls (LTS 4.1°+/-2.8° TSF vs 6.8°+/- 3.9°ACL vs 4.3°+/- 2.3° Control, p=&lt;0.01). Conclusions: This study is the first to depict tibial slope and bone contusion patterns seen in tibial spine injuries, as well as compare rates of meniscal injury and tibial slope between ACL and control patients. Posterior tibial slope is significantly increased in patients who sustain a TSF or ACL injury, suggesting that it may be a risk factor for injury. Similar rates of concomitant meniscal pathology are seen in both TSF and ACL injured patients, which may reflect similar mechanisms of injury. This also highlights that care must be taken to evaluate for additional pathology when treating TSF and ACL injuries. Future study is needed to determine the role, if any, that tibial slope plays in tibial spine fractures as well as to determine if intraarticular pathology identified on MRI influences longer term patient outcomes.

Development of Anatomic Risk Factors for ACL Injuries: A Comparison Between ACL-Injured Knees and Matched Controls

Background: Several tibiofemoral anatomic features have been repeatedly associated with increased anterior cruciate ligament (ACL) injury risk. Previous studies have highlighted age and sex differences among these anatomic risk factors, but little is known about the normal and pathologic development of these differences during skeletal maturation. Purpose: To investigate differences in anatomic risk factors at various stages of skeletal maturation between ACL-injured knees and matched controls. Study Design: Cross-sectional study; Level of evidence, 3. Methods: After institutional review board approval, magnetic resonance imaging scans from 213 unique ACL-injured knees (age, 7-18 years, 48% female) and 239 unique asymptomatic ACL-intact knees (age, 7-18 years, 50% female) were used to measure femoral notch width, posterior slope of the lateral and medial tibial plateau, medial and lateral tibial spinal height (MTSH, LTSH), medial tibial depth, and posterior lateral meniscus-bone angle. Linear regression was performed to assess change in quantified anatomic indices with age for male and female patients in the ACL-injured cohort. Two-way analysis of variance with Holm-Sidak post hoc testing was performed to compare anatomic indices between ACL-injured knees and ACL-intact controls in each age group. Results: In the ACL-injured cohort, notch width, notch width index and medial tibial depth increased with age (R2 > 0.1; P < .001) in both sexes. MTSH and LTSH increased with age only in boys (R2≥ 0.09; P≤ .001), whereas meniscus-bone angle decreased with age only in girls (R2 = 0.13; P < .001). There were no other age differences in quantified anatomic indices. Patients with ACL injury consistently had a significantly higher lateral tibial slope (P < .01) and smaller LTSH (P < .001) as compared with ACL-intact controls across all age groups and sexes. When compared with age- and sex-matched ACL-intact controls, ACL-injured knees had a smaller notch width (boys, 7-18 years; girls, 7-14 years; P < .05), larger medial tibial slope (boys and girls, 15-18 years; P < .01), smaller MTSH (boys, 7-14 years; girls, 11-14 years; P < .05), and larger meniscus-bone angle (girls, 7-10 years; P = .050). Conclusion: The consistent morphologic differences throughout skeletal growth and maturation suggest a developmental role in high-risk knee morphology. The observed high-risk knee morphology at an earlier age preliminarily suggests the potential of knee anatomy measurements in identifying those with a predisposition toward ACL injury.