Non-contact ACL Injury Research Articles

Effectiveness of Injury Prevention Program Using a Global Systems Approach on High-Risk Movement Mechanics for Noncontact ACL Injury.

Injury prevention training using a global systems approach was designed to develop integrated trunk-lower extremity neuromuscular control using whole-body, rotational forces about the vertical Z-axis during simulated sports movements. Compared with traditional hip-focused exercises, injury prevention training using a global systems approach could improve kinetic and kinematic measures related to anterior cruciate ligament injury. Controlled laboratory study. Level 3. A total of 39 male and female athletes received 6 weeks of either global systems approach (n = 20), or hip-focused strengthening, balance, and plyometrics training (n = 19) exercises. Before and after the training program, participants performed a single-leg vertical drop jump task on their dominant leg. Peak vertical ground-reaction forces (GRFs), peak knee abduction, internal rotation moments, peak hip flexion, hip adduction, knee flexion, knee abduction, contralateral pelvic drop, and lateral trunk flexion angles were assessed. Biomechanical data were compared between the 2 groups using a random-intercept linear mixed-models analysis. A significant group × time interaction effect was found for vertical GRFs (P = 0.01; change difference relative to baseline: 4.5%), knee abduction moment (P = 0.01; 14.8%), hip adduction (P < 0.01; 16.7%), knee abduction (P < 0.01; 13.8%), contralateral pelvic drop (P < 0.01; change difference: 26.6%), and lateral trunk flexion (P = 0.04; 20.37%) angles, favoring the global systems approach group after 6 weeks of training. Participants who trained using the global systems approach had significantly decreased lateral trunk flexion, hip adduction, knee abduction and contralateral pelvic drop angles, peak vertical GRFs, and peak knee abduction moment during a single-leg vertical drop jump compared with participants who trained with hip-focused exercises. Incorporating additional external resistance at the proximal trunk results in improved biomechanics compared with conventional hip-focused exercises.

Factors Associated With a Successful Return to Performance After Anterior Cruciate Ligament Reconstruction: A Multiparametric Evaluation in Soccer Players.

Anterior cruciate ligament reconstruction (ACLR) is highly recommended in patients with ACL deficiency who must perform at a high physical level. A combination of functional and psychological outcome measures is necessary to provide a comprehensive evaluation of functional status after successful return to sport after ACLR. To identify factors associated with higher functional outcomes among soccer players who had returned to full sports participation after ACLR. Cohort study; Level of evidence, 3. A total of 168 out of 231 patients who underwent primary unilateral arthroscopic anatomic single-bundle ACLR were available at follow-up. Postoperatively, knee function, generic health outcomes, and psychological impact were assessed using the International Knee Documentation Committee (IKDC), the Knee injury and Osteoarthritis Outcome Score (KOOS), the Lysholm Knee Scoring Scale, the 12-item Short Form Health Survey (SF-12), and the ACL-Return to Sport after Injury scale. After a mean follow-up of 35.5 ± 22.6 months, 85% of soccer players returned to performance. Midfielder position was associated with a better SF-12 Physical Component Summary (PCS) score (P = .013), IKDC (P = .003), total KOOS (P < .001), KOOS Symptoms (P = .004), KOOS Pain (P = .029), KOOS Activities of Daily Living (ADL) (P = .044), KOOS Sport and Recreation (Sport/Rec) (P = .001), KOOS Quality of Life (QoL) (P < .001), and Lysholm score (P = .008). Playing only on natural grass was associated with lower SF-12 PCS scores (P = .003), total KOOS (P = .001), and KOOS Sport/Rec (P = .011). Playing only on artificial turf was associated with lower Lysholm score (P = .018) and total KOOS (P = .014). The contact mechanism was associated with higher IKDC (P = .044) and KOOS QoL (P = .048), and injury affecting the dominant limb was associated with lower SF-12 Mental Component Summary scores (P = .012). Playing at a nonprofessional level was associated with lower total KOOS (P = .028), KOOS Symptoms (P = .002), KOOS ADL (P = .033), and KOOS Sport/Rec (P = .016). Professional soccer players and the midfielder position are associated with better functional scores upon returning to the sport. A history of noncontact ACL injury and playing on a single type of surface are associated with lower functional outcomes upon returning to the sport. Lower mental health scores can be expected after injury of the dominant limb.

LFCI and knee morphological parameters as a risk factor in anterior cruciate ligament tear on magnetic resonance imaging- A case control analysis

BackgroundThe anterior cruciate ligament is commonly injured and multiple risk factors have been studied. But there is paucity of articles considering predictive risk factors of femoral condyle morphology in south Indian population. This study aims to assess distal femoral condyle sphericity as a risk factor in anterior cruciate ligament injury and to correlate it with proximal tibia morphological risk factors. Materials and methodsThis is a case control study including 80 patients with knee MRI aged between 18 and 60.They were grouped into cases (40) and controls (40). Cases being non-contact ACL injuries without multi ligamentous injuries and controls being MRI with ACL intact. Lateral femoral condyle index, posterior tibial slope, medial and lateral tibial depth were measured and compared. The risk factors were analysed with multiple logistic regression. ResultsThe lateral femoral condyle index had a mean value of 0.79 with standard deviation of ± 0.05 in cases group. Control group had a mean value of 0.803 with standard deviation of ± 0.05. Medial tibial slope in cases (8°) was lesser than in control group (7.6°). Lateral tibial slope was found to more among cases group (9.1°) than in control group (7.5°). Medial tibial depth had a mean of 4.07 mm among cases and 3.9 mm among control group. There was a moderate positive correlation between LFCI and Medial Tibial slope among cases that was statistically significant (P = 0.002). In addition, there was a weak negative correlation between LCFI and Medial Tibial Depth that was statistically significant. ConclusionThe lateral femoral condyle index was not found to be significant statistically among ACL injured patients. In our study we concluded that lateral tibial slope was more reliable risk factor in predicting ACL injury when compared to other parameters.

Poster 320: Combined Role of Tibial Cartilage Slope, Knee Laxity, and Lower Extremity Strength as Risk Factors for First-Time, Noncontact ACL Injury in Female Athletes

Objectives: Univariable analyses of knee geometry, anteroposterior (AP) laxity, and muscular strength have revealed associations with risk of first-time, noncontact ACL injury in females. However, multivariable analyses assessing the risk associated with combinations of these factors have been limited. As a result, it is unclear how these factors act interdependently to exacerbate or attenuate risk of injury. Therefore, the purpose of this study was to characterize the risk of first-time, noncontact ACL injury associated with pairwise combinations of factors related to geometry, laxity, and strength. Methods: First-time, noncontact ACL injury events were identified as they occurred in 61 female high school and collegiate athletes over a four-year period. Simultaneously, 61 sex- and age-matched control subjects, with no history of lower extremity injury, were selected from the same team. Magnetic resonance imaging was acquired bilaterally, and articular geometries were obtained. On contralateral, uninjured case and control knees, AP knee translation was measured using a KT-2000 arthrometer, knee flexion strength was measured with a Biodex System 2, and hip adduction strength was measured using a fixated, isometric dynamometer. Six features were considered: (1) slope of the lateral tibial plateau articular cartilage not covered by meniscus (“middle cartilage slope”) and (2) covered by the posterior horn of the meniscus (“posterior cartilage slope”), (3) AP translation of the tibia relative to the femur, (4) posterior stiffness, (5) knee flexion strength, and (6) hip adduction strength. First, each feature was compared between cases and controls using Student’s t-test (α = 0.05). Next, the features were used to build a generalized additive model with two pairwise interactions, with ACL injury as the dependent variable. Univariable relationships between each feature and absolute risk of ACL injury, as well as pairwise interaction effects, were inspected with partial dependence plots, which describe the (potentially nonlinear) shape of those associations. Absolute risk was defined as the change in probability of experiencing an ACL injury associated with varying values of each feature, accounting for the average effect of all other features. For example, an absolute risk value of 0.2 signifies a 20% increase in absolute risk. Results: Compared to their uninjured teammates, injured athletes had greater middle cartilage slope (0.6° ± 3.8° vs. -3.8° ± 4.2°, p &lt; 0.001) and greater posterior cartilage slope (13.3° ± 6.3° vs. 8.5° ± 5.5°, p &lt; 0.001) of the lateral tibial plateau. Injured subjects also had greater AP laxity (15.0 ± 3.0 mm vs. 13.6 ± 2.4 mm, p = 0.006) than uninjured controls. Partial dependence plots for each of the six features show associations with absolute risk (Figure 1). The two pairwise interaction effects identified were lateral middle cartilage slope with hip adduction strength (Figure 2) and lateral posterior cartilage slope with AP translation (Figure 3). The first revealed that the increase in risk associated with increasing middle tibial cartilage slope was larger in athletes with decreased hip adduction strength (and smaller in athletes with increased hip adduction strength). The second revealed that the increase in risk associated with increasing posterior tibial cartilage slope was larger in athletes with increased AP translation (and smaller in athletes with decreased AP translation). Conclusions: In this cohort of high school and collegiate female athletes, the model revealed two important interactions among lateral tibial cartilage slope, hip adduction strength, and knee laxity. Increased hip adduction strength and decreased AP translation both acted in combination to decrease risk of first-time, noncontact ACL injury in athletes with greater cartilage slope. The risk associated with increased middle cartilage slope may be reduced in athletes with greater hip adduction strength (Figure 2). This could be explained by an increase in femoral stability with stronger muscular forces. Moreover, clinicians should pay close attention to patients presenting with increased AP translation and greater posterior cartilage slope, as these features interacted to exacerbate risk of injury in our cohort (Figure 3). Conversely, decreased AP translation may stabilize the knee in the presence of greater posterior cartilage slope, reducing the risk associated with this geometry. In assessing risk of first-time, noncontact ACL injury, lateral tibial cartilage slope measurements should be considered in conjunction with laxity- and strength-related factors. [Figure: see text][Figure: see text][Figure: see text]

Neurocognitive Errors and Noncontact Anterior Cruciate Ligament Injuries in Professional Male Soccer Players.

Evidence is emerging that core neurocognitive functions such as working memory and inhibitory control (ie, motor-response and attentional inhibition) are linked to the anterior cruciate ligament (ACL) injury risk. Research has been conducted in laboratory settings, but the contribution of neurocognition to actual ACL injuries under real-world conditions is unknown. To describe the possible neurocognitive errors involved in noncontact ACL injury mechanisms. Case series. Soccer matches. A total of 47 professional male soccer players. Three independent reviewers evaluated 47 videos of players sustaining noncontact ACL injuries. Neurocognitive errors in inhibitory control were operationalized as follows: (1) motor-response inhibition was scored when a player demonstrated poor decision-making and approached the opponent with high speed that reduced the ability to stop or change the intended action and (2) an attentional error was scored when a player shifted his selective attention away from the relevant task to irrelevant stimuli. Of 47 noncontact ACL injuries, 26 (55%) were related to a pressing-type injury, 19 (73%) of which involved a deceiving action made by the opponent, suggesting poor inhibitory control of the defender. Of the remaining 21 noncontact ACL injuries (45%), 16 (76%) could be attributed to attentional errors. Agreement among the 3 raters was very good for all items except poor decision-making, which showed fair to good agreement (Fleiss κ = 0.71). Interrater reliability was excellent (intraclass correlation coefficient = 0.99-1.00). Errors in motor-response inhibitory control and attentional inhibition were common during noncontact ACL injury events in professional male soccer players. The interrater agreement in detecting neurocognitive errors in general was very good.

The effects of two different fatigue protocols on movement quality during anticipated and unanticipated change of directions in female soccer players.

This study compared neuromuscular control under two fatigue protocols during anticipated and unanticipated change of direction (COD) maneuvers and evaluated their effects on the risk of non-contact ACL injuries. Forty-five female soccer players (mean age: 22.22 ± 2.24 years; mean height: 166.24 ± 3.33 cm; mean mass: 59.84 ± 5.03 kg) were divided into three groups: functional fatigue (Soccer specific fatigue ptotocol-SOFT90), non-functional fatigue (Bruce protocol), and control group. Before and after the implementation of neuromuscular control fatigue protocols were evaluated using the cutting motion assessment score tool (CMAS). Two-dimensional (2D) videos were recorded during anticipated and unanticipated COD trials for both dominant and non-dominant legs. Significant time effects (p < 0.05) and group-time interactions (p < 0.05) were observed in both anticipated and unanticipated conditions for both dominant and non-dominant legs after the fatigue protocols. The functional fatigue group exhibited higher CMAS changes, indicating poorer movement quality following fatigue. Notably, the non-dominant leg displayed amplified deficits during unanticipated COD maneuvers following the functional fatigue protocol. Fatigue significantly impairs neuromuscular control, particularly in unanticipated COD situations, which increases the risk of non-contact ACL injuries. To mitigate this risk, coaches, trainers, and medical professionals should prioritize targeted training and injury prevention strategies, focusing on the non-dominant leg during unanticipated COD maneuvers.

The Risk Factors Affected Upon Non-Contact ACL Injury in Gymnastics, Swimming and Basketball Collegiate Student Female Players

The purpose of the present study was to determine of the risk factors affected upon non-contact ACL injury in Gymnastics, Swimming and basketball collegiate student female players. If an athlete injured anterior cruciate ligament the most important thing is to identify factors that affect the injury. However, growing research implicates hormonal, anatomical, environmental and neuromuscular factors that may predispose athletes to these injuries. For this research selected 510 athletes for assess ACL injury factors by two different methods (A) Questionnaire and (B) Interview that information collected among athletes who were play Gymnastics, Swimming and basketball. Our results indicate 61.4% of ACL injury occurred in practice time and 38.6% of ACL injury was during competition. Also, our finding showed that 69% mechanism of injury was non-contact, 4.7% via accident and 26.3% with unknown reason. Furthermore, dynamic alignment at the time of the injury included: Knee-in &amp; Toe- out 44%, Knee-out &amp; Toe-in 22.5 and Hyperextension 11.1%. The ACL prevents the femur from moving forward during weight bearing. It also helps to prevent rotation of the joint. Injury of the ACL most often occurs when an athlete is pivoting, decelerating suddenly or landing from a jump. The injury can also be caused by another player falling across the knee. ACL injuries are, probably, the most common devastating knee ligament injuries amongst sports persons. Usually these injuries are isolated, mainly in non-contact sports, but many often are a part of more complex ligamentous injuries. They occur more often in contact sports, such as basketball. In conclusion, our study produced strong evidence in support of a significant some factors influencing of ACL injury in Gymnastics, Swimming and basketball collegiate student female players.

Low speed isokinetic knee extensors and flexors strength of soccer players is not predicting non-contact ACL injury

Low speed isokinetic knee extensors and flexors strength of soccer players is not predicting non-contact ACL injury

Two-Dimensional and Three-Dimensional Biomechanical Factors During 90° Change of Direction are Associated to Non-Contact ACL injury in Female Soccer Players.

The two-dimensional (2D) video-analysis of the change of direction (COD) technique has never been used to attempt to predict the risk of ACL injury in female football players. The purpose of the present pilot study was to prospectively investigate the biomechanical predictors of ACL injury during a COD task in female football players using both gold standard 3D motion capture and a qualitative scoring system based on 2D video-analysis. Prospective cohort study. Sixteen competitive female football (soccer) players (age 21.4 ± 4.3) performed a series of pre-planned 90° COD tasks. 3D motion data was recorded through 10 stereophotogrammetric cameras and a force platform. 2D frontal and transverse plane joint kinematics were computed through video-analysis from three high-speed cameras. A scoring system based on five criteria was adopted: limb stability, pelvis stability, trunk stability, shock absorption, and movement strategy. The players were prospectively followed for the next two consecutive football seasons and the occurrence of severe knee injuries was registered. Four players (25%) experienced an ACL injury. In 3D analysis, ACL-injured players showed greater knee valgus, knee internal rotation, and lower knee flexion (p= 0.017 - 0.029). Lower hip flexion coupled with greater external rotation (p= 0.003 - 0.042), ankle eversion, and contralateral pelvic drop (p<0.001) were also noted. In 2D analysis, ACL-injured players showed greater internal foot rotation, contralateral pelvic drop, lower knee flexion, and contralateral trunk tilt (moderate-to-large effect size). Pelvis stability and trunk stability showed the highest predictive value towards ACL injury. Total score was significantly lower in ACL-injured players with a moderate effect size (d=0.45). Both 3D and 2D methodologies depicted biomechanical risk factors and offered predictive insights towards the ACL injury risk. Awareness should rise in women's football regarding the high risk of ACL injury and the strategies to assess and mitigate it. 3©The Author(s).

Poster 342: Anterior Cruciate Ligament Reconstruction in Recreational Athletes Aged 40 and Older: Activity Level as an Indication

Objectives: The number of patients that are continuing to be active is extending into middle age. Many in this population report consistent participation in recreational sports. Anterior cruciate ligament reconstruction (ACLR) is the gold standard for treatment among young athletic patients, but nonoperative treatment has historically been utilized more often in older patient populations. It has been traditionally thought that older adult patients do not share the same activity level as younger patients and thus are not in need of surgical treatment of an ACL injury. There is some hesitancy to treat older patients if they have mild to moderate pre-existing arthritis, but in recent years the literature has demonstrated good outcomes in this population. The type of graft used in older patients is another source of controversy, with many surgeons opting to use allograft rather than a patient’s native tissue for ACLR. Factors that can inform decision-making such as pre-injury activity level and employment have not been thoroughly assessed for these patients. The purpose of this study was to better understand indications for ACLR in patients aged 40 and older by characterizing their activity level, mechanisms of injury, employment status, demographics, surgical characteristics, and patient reported outcomes (PROs). Methods: A registry of prospectively-collected PROs from a single metropolitan ambulatory surgical center was retrospectively reviewed for patients that received an ACLR from 2009-2016. Patients younger than 40 years old, revision procedures, and concomitant ligament repairs or reconstructions were excluded. Demographic, employment, activity, injury, and surgical characteristics were extracted via chart review. The level of strength required by the patient’s occupation was stratified by the definitions from the United States Department of Labor Occupation Requirements Survey (graded as “sedentary”, “light work”, “medium work”, “heavy work”, “very heavy work”). Surgical outcomes include ACLR failure or re-rupture, ipsilateral knee re-operations, and complications. PROs utilized were the Single Assessment Numeric Evaluation (SANE) and Knee Injury &amp; Osteoarthritis Outcome Score (KOOS) collected pre-operatively and at two years post-operatively. Results: A total of 141 patients were identified. More than half the patients were female (n=81, 58%) and the average age was 47 years old (range: 40-66). Approximately 87% (n=124) of patients had PRO data. The average KOOS and SANE at two-year follow-up were 80.0 ± 15.9 and 85.3 ± 22.0, respectively. The average change from baseline score were 20.8 ± 20.2 and 24.1 ± 30.3 for KOOS and SANE, respectively. Pre-existing arthritis was found in the majority of patients (n=88, 62%). The most common graft type used for ACLR in this group was allograft (n=95, 67%). Injured menisci were typically treated with meniscectomy vs repair (n=65, 56%). The majority of patients (n=104, 77%) were engaged in a sport when they sustained an ACL injury, with 96% being engaged in a sport that requires running, jumping, and other high-impact activity. Those injured while involved in a sport on average demonstrated higher KOOS scores at baseline and at two-year follow up compared to those that were not involved in a sport (61.5 ± 18.0 vs 51.6 ± 18.0 at baseline, p=0.045; 82.8 ± 13.7 vs 70.8 ± 19.5 at two years, p=0.0048). A total of 27 of the sporting-related injuries occurred in patients age 50 or older (60% of n=45 patients age 50 years or older). All of these patients expressed a desire to return to sport and pre-injury activity. Skiing was the most frequently cited sport (n=41, 29%). Most ACL injuries were acute, with just 10% found to be chronic. The mechanism of injury varied by activity, but non-contact type ACL injuries were the most prevalent (n=66, 49%). Although most patients worked in a sedentary or desk job environment (n=87, 65%), some worked in very heavy-duty jobs (n=18, 14%). There was a low incidence of re-ruptures and re-operations (4.5% and 8.7%, respectively). Conclusions: The majority of patients aged 40 and over sustained ACL injuries while engaging in sports, with all of these patients citing a desire to return to sport and pre-injury activity level as their reason for wanting an ACLR. Patients were mostly treated with allograft compared to autograft, and meniscal injuries were most frequently treated through meniscectomy instead of repair. Many of these patients had some form of pre-existing arthritis and still went on to have surgery with excellent outcomes. PROs were also found to be higher initially and at two-year follow-up in the more active adult group, suggesting that pre-injury and post-injury activity level is associated with improved outcomes. When an older adult patient presents with an ACL tear, surgeons should consider the activity level and desires of the patient as they determine the appropriate avenue of treatment. There is certainly a role for conducting ACLR in patients aged 40 or older. [Table: see text][Table: see text][Table: see text]

Video Analysis of 26 Cases of Second ACL Injury Events in Collegiate and Professional Athletes.

Significant effort has gone into the identification and quantification of the underlying mechanisms of primary ACL injury. Secondary ACL injury is observed in approximately 1/4 to 1/3 of athletes who return to sport following ACL reconstruction. However, little has been done to evaluate the mechanisms and playing circumstances surrounding these repeat injuries. The purpose of this study was to characterize the mechanisms of non-contact secondary ACL injuries using video analysis. It was hypothesized that in video recordings of secondary ACL injury, athletes would exhibit greater frontal plane hip and knee angles, but not greater hip and knee flexion, at 66 ms following initial contact (IC) as compared to at IC and 33ms following IC. Cross-Sectional Study. Twenty-six video recordings of competitive athletes experiencing secondary ACL ruptures via noncontact mechanisms were analyzed for lower extremity joint kinematics, playing situation, and player attention. Kinematics were assessed at IC as well as 33 ms (1 broadcast frame) and 66 ms (2 broadcast frames) following IC. Knee flexion and knee frontal plane angles were greater at 66 ms than IC (p ≤ 0.03). Hip, trunk, and ankle frontal plane angles were not greater at 66 ms than IC (p ≥ 0.22). Injuries were distributed between attacking play (n=14) and defending (n=8). Player attention was most commonly focused on the ball (n=12) or an opponent (n=7). A single-leg landing accounted for just over half of the injuries (54%), while a cutting motion accounted for the remainder of the injuries (46%). Secondary ACL injury was most likely to occur during landing or a sidestep cut with player attention external to their own body. Knee valgus collapse combined with limited hip motion was identified in the majority of secondary injuries. Level IIIb.

Gender Comparisons and Associations between Lower Limb Muscle Activation Strategies and Resultant Knee Biomechanics during Single Leg Drop Landings

(1) Background: We aimed to compare gender differences in knee biomechanics and neuromuscular characteristics, and to determine the relationships between lower limb muscle pre-activations and knee biomechanics during a single leg drop landing, in order to identify riskier landing patterns to prevent injury and intervene properly. (2) Methods: Descriptive laboratory cross-sectional study on 38 healthy untrained subjects with low to moderate physical activity status. (3) Results: During the initial-contact phase of landing, females demonstrated greater peak vertical ground reaction force (GRF) normalized to body weight (49.12 ± 7.53 vs. 39.88 ± 5.69 N/kg; p &lt; 0.001; Hedge’s g = 1.37), peak knee anterior reaction force normalized to body weight (0.23 ± 0.04 vs. 0.17 ± 0.05 N/kg; p &lt; 0.001; Hedge’s g = 1.33), and decreased pre-activation of the semitendinosus (45.10 ± 20.05% vs. 34.03 ± 12.05%; p = 0.04; Hedge’s g = 0.67). The final regression equation was peak knee anterior reaction force = 0.024 + 0.025 (peak knee flexion moment) − 0.02 (semitendinosus-to-vastus lateralis pre-activation ratio) + 0.003 (peak vertical GRF) (R2 = 0.576, p &lt; 0.001). (4) Conclusions: Overall, the data provided in this study support that a reduced semitendinosus-to-vastus lateralis pre-activation ratio predicted an increase in knee anterior reaction force and potentially an increase in ACL forces. Female non-athletes had gender-specific landing characteristics that may contribute to ACL injury. Future studies are warranted to consider more possible predictors of non-contact ACL injury.

Lower Kinetic Chain, Meet the Thinking Brain: A Scoping Review of Cognitive Function and Lower Extremity Injury Risk

The classic model of non-contact ACL injury includes environmental, anatomical, hormonal and biomechanical risk factors which directly impact either the amount of stress placed on the ligament or the relative capacity of ligament to withstand the forces placed on it. However, cognition also clearly plays a role in successful athletic performance, yet diminished cognitive function is rarely considered a risk factor for injury. Objective To examine the existing literature to determine the extent to which cognitive function (both cognitive ability and task cognitive load) influences non-contact lower extremity injury risk in male and female athletes with a broad variety of athletic expertise. Study Design Scoping Review Methods An electronic search was conducted of CINAHL, SPORTDiscus, Google Scholar, and MEDLINE using the PRISMA method. Search terms included Boolean combinations of “cognition”, “concussion”, “ImPACT”, “cognitive deficit”, “mild traumatic brain injury (mTBI)”, and “neuropsychological function” as cognitive descriptors and the terms “injury risk” and “lower extremity injury” as injury descriptors. Inclusion criteria included papers written in English published between 2000-2021. Exclusion criteria included neurological and cognitively atypical populations, except for concussion (included). Included articles were appraised using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Results Fifty-six studies utilizing across the spectrum of levels of evidence met inclusion criteria. Forty-one articles had good, fourteen had fair, and one had poor methodological quality. Studies examined baseline cognitive function in healthy athletes (n=7); performance during dual-task paradigms (n=13); and the impact of concussion on dual-task performance (n=4), LE injury risk (n=22), or post-concussion testing (n=10). Six articles examining cognitive function and all dual-task studies (including concussion studies) found altered biomechanics associated with injury or increased processing demands. Studies related to concussion and injury incidence consistently found an increased risk of LE injury following concussion. Half of the studies that examined concussion and post-concussion cognitive testing demonstrated significant effects. Discussion Consistent across participant demographics, tasks, and dependent measures, fifty-one of fifty-six assessed articles concluded that decreased cognitive ability or increased cognitive load led to risky LE mechanics or a direct increase in non-contact LE injury risk. Conclusion The robustness of results across gender, performance level, sport, cognitive ability, task cognitive load suggest that the inclusion of cognitive training in the design of optimal LE injury prevention programs warrants further study. Level of Evidence: Ia

Ski-geometric parameters do not differ between ACL injury mechanisms in recreational alpine skiing

PurposeIt is not known so far if ski-equipment-related factors differ between the ACL injury mechanisms, potentially influencing the circumstances and causes of falling, finally resulting in ACL injury. More specifically focusing on the injury mechanisms will provide a deeper understanding of injury causation. The aim of the study was to evaluate whether ACL injury mechanisms in recreational alpine skiing differ with regard to ski-geometric parameters, self-reported circumstances and causes of accident and injury severity.MethodsAmong a cohort of 392 ACL-injured (57.9% females) skiers, age, sex, height, weight, skill level, risk-taking behavior, circumstances and causes of accident, and ACL injury severity were collected by questionnaire. Additionally, patients had to recall their type of fall (ACL injury mechanism) by classifying forward and backward falls with and without body rotation. Ski length, side cut radius and widths of the tip, waist and tail were directly notated from the ski.ResultsThe forward fall with body rotation was the most common reported ACL injury mechanism (63%). A riskier behavior was associated with forward falls without body rotation. Ski-geometric parameters did not significantly influence the type of ACL injury mechanism. Regarding accident characteristics, catching an edge of the ski was more frequent (p < 0.001) the cause for forward falls (75% and 67%) when compared to the backward falls (46 and 15%) and executing a turn was the most frequent action in all falls (39–68%). A complete rupture of the ACL (66–70%) was more commonly reported than a partial tear (30–34%) among all four non-contact ACL injury mechanisms (n.s.).ConclusionIn contrast to risk-taking behavior and accident characteristics, ski-geometric parameters and injury severity do not significantly differ between ACL injury mechanisms in recreational skiing. Thus, an individual skiing style seems to have more impact on ACL injury mechanisms than ski equipment. Future studies should evaluate potential effects of ski geometry on the incidence of ACL injury.Level of evidenceIII.

Effect of menstrual cycle phase, menstrual irregularities and hormonal contraceptive use on anterior knee laxity and non-contact anterior cruciate ligament injury occurrence in women: a protocol for a systematic review and meta-analysis

Exercising women report three to six times more ACL tears than men, which happen, in the majority of cases, with a non-contact mechanism. This sex disparity has, in part, been...

Analysis of Different Stop-Jumping Strategies on the Biomechanical Changes in the Lower Limbs

The stop-jumping task is one of the most important technical actions in basketball. A previous study showed 70% probability of non-contact ACL injuries during stop-jumping tasks. Therefore, the present study aimed to investigate the differences in lower extremity biomechanical changes between the rear foot as the initial contact area to terminate the jump (SJR) and the fore foot as the initial contact area to also terminate the jump (SJF) during the horizontal landing during a stop-jumping phase. In total, 25 male amateur Ningbo University basketball athletes from China were recruited for this study. The participants were asked to jump vertically by using two different stop-jumping strategies. Kinematic and kinetics data were amassed during a stop-jumping task. Statistical parametric mapping (SPM) analysis was used to find the differences between SJR and SJF. Our results indicated that the change of different ankle range of motion caused significantly different values for knee angle (p &lt; 0.001), velocity (p = 0.003) (p = 0.023) (p &lt; 0.001), moment (p = 0.04) (p &lt; 0.001), (p = 0.036) and power (p = 0.015) (p &lt; 0.001) during the stop-jumping phase and the horizontal landing phase. The same biomechanical parameters of the hip joint were also significantly different for hip angle (p &lt; 0.001), moment (p = 0.012) (p &lt; 0.001) (p &lt; 0.001), and power (p = 0.01) (p &lt; 0.001) (p &lt; 0.001). These findings indicate that altering the primary contact at the ankle angle might effectively reduce the risk of a knee injury.

Temporal kinematic and kinetics differences throughout different landing ways following volleyball spike shots

Volleyball players often land on a single leg following a spike shot because of a shift in the center of gravity. This landing is one of the high-risk actions for non-contact ACL injury. The purpose of this study was to compare and analyze the discrete and temporal kinematics and kinetics associated with functional valgus collapse during volleyball in player landing phases during a single-leg landing and double-leg landing following a spike shot. Kinematics and kinetics data were collected (captured by a Vicon motion system and AMTI force plate, processed by Visual-3D software) during the single-leg and double-leg landing phases in 13 semi-professional male volleyball players. The landing phase was defined as initial ground contact (0% landing phase) to maximum knee flexion (100% landing phase). Statistical Parametric Mapping (SPM) analysis revealed that single-leg landing depicted a significantly greater knee abduction angle and hip adduction moment than double-leg landing during the 0%–68% landing phase (single-leg: 7°–16°, double-leg: 0°–9°, p &lt; 0.001) and 18%–22% (single-leg: 0.62–0.91 Nm/kg, double-leg: 0.08–0.19 Nm/kg, p = 0.0063) landing phase, respectively. The traditional discrete analysis revealed that single-leg landing depicted a significantly greater peak knee internal rotation moment (single-leg: 1.46 ± 0.38 Nm/kg, double-leg: 0.79 ± 0.19 Nm/kg, p = 0.006) and peak hip internal rotation moment (single-leg: −2.20 ± 0.54 Nm/kg, double-leg: −0.88 ± 0.30 Nm/kg, p = 0.011) than double-leg landing. Most differences were within a time frame during the landing phase of 30–50 ms in which non-contact ACL injuries are considered to happen. These recorded time frames are consistent with biomechanical measures that are deemed dangerous. To reduce lower limb injury, a volleyball player should consciously swing the arms to influence the body to maintain a better-balanced state. Adjusting the landing mode of the lower limbs can achieve a good cushioning effect during landing following a spike shot.

Normal anatomical variations of tibial plateau geometry in Indian population: a magnetic resonance image-based study

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; Geometry of tibial plateau characterized by its medial tibial plateau slope (MTS), lateral tibial plateau slope (LTS), depth of concavity of medial tibial plateau (CMT), convexity of lateral tibial plateau on sagittal section and coronal tibial plateau slope (CTS) on coronal section of tibia.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods:&lt;/strong&gt; 500 subjects (male-250, female-250) were included in the study. Various tibial slopes of each subject were measured using magnetic resonance image (MRI) of knee joint. Data was analysed using appropriate statistical analysis.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results:&lt;/strong&gt; When considering male and female one group (total population) mean (±SD) of MTS, LTS, CMT, CTS were 7.73±3.20&lt;sup&gt;0&lt;/sup&gt;, 4.68±2.75&lt;sup&gt;0&lt;/sup&gt;, 2.56±0.56 mm and 2.61±2.15&lt;sup&gt;0&lt;/sup&gt; respectively. In male population mean (±SD) of MTS, LTS, CMT, CTS were 6.94±3.2&lt;sup&gt;0&lt;/sup&gt;, 3.77±1.85&lt;sup&gt;0&lt;/sup&gt;, 2.7±0.55 mm, 3.06±2.39&lt;sup&gt;0 &lt;/sup&gt;respectively. In female population population mean (±SD) of MTS, LTS, CMT, CTS were 9.28±2.65&lt;sup&gt;0&lt;/sup&gt;, 6.45±3.36&lt;sup&gt;0&lt;/sup&gt;, 2.28±0.48 mm, 1.75±1.24&lt;sup&gt;0&lt;/sup&gt; respectively. Over all MTS and LTS was poorly correlated (r=0.43). Female had significant steeper MTS (p=0.013) and LTS (p=0.001) but had less CTS (p=0.04) and shallow CMT (p=0.012) compared to male.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;Knowledge of this study could be used in different operative orthopaedic procedures (like knee arthroplasty, high tibial osteotomy, tibial plateau fracture fixation), non-contact ACL injury risk assessment.&lt;/p&gt;&lt;p&gt; &lt;/p&gt;

Post-Trial Feedback Alters Landing Performance in Adolescent Female Athletes Using a Portable Feedback System

BackgroundPost-performance verbal and visual feedback based on data collected via lab-based instruments have been shown to improve landing patterns related to non-contact ACL injury. Biomechanical methods are often complex, difficult to transport and utilize in field settings, and costly, which limits their use for injury prevention. Developing systems that can readily provide feedback outside of the lab setting may support large scale use of feedback training for ACL injury prevention.Purpose/HypothesisThe purpose of this study was to investigate the effectiveness of a single training session using a custom portable feedback training system that provides performance cues to promote changes in impact kinetics and lower extremity position during landing in female athletes.Study DesignRepeated measuresMethodsOne hundred fifty female athletes (ages 13-18 years old) landed from a 50 cm platform with and without feedback related to vertical ground reaction force (vGRF), vGRF symmetry and lower extremity position. Feedback was provided via a portable, low-cost system that included two custom-built force plates interfaced with a digital camera. Each athlete performed six pre-test trials followed by two blocks of six trials where they received visual feedback from the training system and individualized verbal cues from an investigator. Following training blocks, athletes completed six post-test trials without feedback and then six dual-task trials where a ball was randomly thrown to the performer during the landing (transfer task). vGRF and knee to ankle (K:A) separation ratio were measured and the average responses were reported for each trial block.ResultsDifferences in vGRF between baseline, post-test and transfer task trial blocks were observed (F(2,298)=181.68, p < .0001). Mean (SD) peak vGRF (body weight) were 4.43 (0.90), 3.28 (0.61), and 3.80 (0.92), respectively. Differences in K:A ratio between baseline, post-test and transfer task trial blocks were shown (F(2,298)=68.47, p < .0001). Mean (SD) K:A ratio were 0.87 (0.21), 0.98 (0.19), and 0.92 (0.19), respectively.ConclusionA portable feedback system may be effective in reducing peak vGRFs and promoting a more desirable K:A ratio during landing and transfer task landing in adolescent female athletes.Level of Evidence3b

Sex-specific landing biomechanics and energy absorption during unanticipated single-leg drop-jumps in adolescents: implications for knee injury mechanics

Females aged between 13 and 17 years old possess the highest non-contact ACL injury incidence of any sex-age strata. Considering that energy absorption strategies have been associated with a reduced risk for sustaining an ACL injury, evaluating landing performance in youth athletes requires investigations beyond the kinematic level. The purpose of this study was to identify sex-specific energy absorption strategies in adolescent males and females, including the relationship between strength and the observed strategies. Thirty-one healthy adolescent athletes completed unanticipated single-leg drop-jump landings on their dominant limb. Sex-specific kinematics and lower-limb contributions to energy absorption were then compared over the landing phase for each jump. Pearson and Spearman correlation coefficients determined the relationship between isometric joint strength and the observed kinematics and energy absorption. Female participants absorbed a larger proportion of the landing energy at the ankle (p = 0.046, d = 0.75) and smaller proportion at the hip (p = 0.028, d = 0.85) compared to males. Females also reached larger peak negative joint power in their knee (p = 0.001, d = 1.1) and ankle (p = 0.04, d = 0.79). Hip extension strength was positively correlated with trunk flexion (r = 0.559, p = 0.001) and negatively correlated with forward pelvic tilt (r = -0.513, p = 0.003). Females adopted an energy absorption strategy which utilized the distal joints to absorb a larger portion of the landing forces and tended to absorb the forces later in the landing phase relative to males. The greater reliance on distal joints is correlated to reduced hip strength and may increase the risk for sustaining an ACL injury.