Non-contact Knee Injury Research Articles

Do Sex-Specific Differences Exist in ACL Attachment Location? An MRI-Based 3-Dimensional Topographic Analysis.

Background:Female sex is an independent risk factor for an anterior cruciate ligament (ACL) injury, as the incidence of an ACL rupture is 4- to 6-fold higher in female athletes compared with their male counterparts. The ACL attachment location as a potential risk factor for the increased ACL rupture rate in women has never been reported in the literature.Purpose/HypothesisThe purpose of the present study was to investigate the 3-dimensional topographic anatomy of the ACL bundle attachment in female and male patients, with and without an ACL rupture, and identify potential sex-related differences. We hypothesized that the ACL attachment location would be significantly different between men and women, in both the intact- and ruptured-ACL states.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Magnetic resonance images of the knee from 90 patients (55 men, 35 women) with a ruptured ACL and 90 matched controls (55 men, 35 women), who suffered a noncontact knee injury without ACL rupture, were used to create 3-dimensional models of the femur and tibia. The ACL bundles’ origin and insertion were outlined on each model, and their location was measured using an anatomical coordinate system. A 2-way analysis of variance was used to compare the ACL attachment location between male and female patients, with and without an ACL rupture.Results:No significant differences were found between female and male participants regarding ACL attachment location (femoral origin and tibial insertion). Patients with a ruptured ACL demonstrated a significantly different ACL origin compared with the participants with an intact ACL by an average difference of 8.9% more posterior (P < .05) and 4.0% more proximal (P < .05) in men and 13.0% more posterior (P < .05) and 5.5% more proximal (P < .05) to the flexion-extension axis of the knee in women.Conclusion:The ACL attachment location should not be considered a risk factor for the increased ACL rupture rates in female compared with male athletes. However, a more posterior and proximal location of the femoral ACL origin might be a predisposing factor to an ACL rupture regardless of sex.

Multidimensional Ground Reaction Forces and Moments From Wearable Sensor Accelerations via Deep Learning.

Monitoring athlete internal workload exposure, including prevention of catastrophic non-contact knee injuries, relies on the existence of a custom early-warning detection system. This system must be able to estimate accurate, reliable, and valid musculoskeletal joint loads, for sporting maneuvers in near real-time and during match play. However, current methods are constrained to laboratory instrumentation, are labor and cost intensive, and require highly trained specialist knowledge, thereby limiting their ecological validity and wider deployment. An informative next step towards this goal would be a new method to obtain ground kinetics in the field. Here we show that kinematic data obtained from wearable sensor accelerometers, in lieu of embedded force platforms, can leverage recent supervised learning techniques to predict near real-time multidimensional ground reaction forces and moments (GRF/M). Competing convolutional neural network (CNN) deep learning models were trained using laboratory-derived stance phase GRF/M data and simulated sensor accelerations for running and sidestepping maneuvers derived from nearly half a million legacy motion trials. Then, predictions were made from each model driven by five sensor accelerations recorded during independent inter-laboratory data capture sessions. The proposed deep learning workbench achieved correlations to ground truth, by maximum discrete GRF component, of vertical Fz 0.97, anterior Fy 0.96 (both running), and lateral Fx 0.87 (sidestepping), with the strongest mean recorded across GRF components 0.89, and for GRM 0.65 (both sidestepping). These best-case correlations indicate the plausibility of the approach although the range of results was disappointing. The goal to accurately estimate near real-time on-field GRF/M will be improved by the lessons learned in this study. Coaching, medical, and allied health staff could ultimately use this technology to monitor a range of joint loading indicators during game play, with the aim to minimize the occurrence of non-contact injuries in elite and community-level sports.

Noncontact Knee Soft-Tissue Injury Prevention Considerations and Practical Applications for Netball Players

ABSTRACT Netball is a team sport played worldwide. High-risk landing events containing biomechanical potential for noncontact knee soft-tissue injury (STI) occur frequently. Subsequently, noncontact knee STI is common after knee abduction collapse during landing tasks. Lower-limb mobility, strength, balance, movement, and hop test characteristics (intrinsic, modifiable risk factors) are associated with high-risk landing biomechanics and noncontact knee STI events. Such risk factors should be considered in netball-specific noncontact knee STI prevention preparticipation screening. Corresponding training methods should be included as indicated in netball-specific multimodal noncontact knee STI prevention programs. This article provides insight into noncontact knee injury–related aspects of netball and gives detailed suggestions for injury prevention screening and programming.

A model for potential non-contact ski injuries of the knee

Broadly accepted is that most knee injuries result from increased vertical forces, usually induced by an incidental ski fall, collision, or a high jump. We present a new non-contact knee injury mechanism that can happen during a ski turn. Such an injury is governed by a sudden inward turn of the inner ski and consequent swing of the inner leg followed by a nearly instant stop when locked by hip and knee joints. The model provides predictive results for a lateral tibial plateau compression fracture because several simplifications have been made. We confirmed that the modelled compression stresses at typical skiing conditions and with typical skiing equipment can provoke serious knee injuries. The awareness of skiers and skiing equipment industry of the described knee injury mechanism can act as an important injury-prevention factor.

Return to sports bridge program improves outcomes, decreases ipsilateral knee re-injury and contralateral knee injury rates post-ACL reconstruction.

To present the results of a return to sports bridge program designed to reduce knee injuries following ACL reconstruction and physical therapy. One hundred and fifty (male = 83, female = 67) patients participated in a whole body neuromuscular control, progressive resistance strength and agility training program. Post-program testing included functional movement form, dynamic knee stability, lower extremity power, agility, and sports skill assessments. Participants completed the Knee Outcome Survey-Sports Activity Scale (KOS-SAS) before and after program initiation. Pre-participation scores were re-estimated following program completion. Global rating KOS-SAS score at program entry was 75 ± 13. Post-program global rating and calculated KOS-SAS were 91.0 ± 9.8 and 90.9 ± 9.7, respectively (p < 0.0001). Pre-participation KOS-SAS score re-estimates at program completion were 54.5 ± 23.3 and 57.3 ± 18.5, respectively. The approximately 20% lower pre-program KOS-SAS score re-estimates (p < 0.0001) observed at program completion suggests that subjects had inaccurately high sports readiness perceptions at program entry. Perceived overall sports activity knee function ratings improved from 2.9 ± 0.6 (abnormal) at program entry to 1.3 ± 0.5 (normal) at completion (p < 0.0001). Most subjects returned back to sports at or above their pre-injury performance skill/performance level (84%, 126/150). By 6.8 ± 3.2years (range = 2-13years) post-surgery, ten subjects had sustained an ipsilateral knee re-injury or contralateral knee injury (6.7%). The 2.7% non-contact contralateral and 1.3% non-contact ipsilateral knee injury rates observed were significantly lower than those citedin previous reports. Supplementing primary ACL reconstruction and standard physical therapy with a return to sports bridge program prior to release to unrestricted sports performance was effective at improving patient outcomes and decreasing ipsilateral knee re-injury and contralateral knee injury rates. II.

Influence of Anticipation and Motor-Motor Task Performance on Cutting Biomechanics in Healthy Men

Biomechanical analyses of cutting tasks have demonstrated kinematic differences associated with the noncontact knee-injury risk when the movement direction is unanticipated. Motor-motor dual tasks occur within dynamic environments and change the demand for attentional resources needed to complete athletic maneuvers, which may contribute to injury risk. To investigate the influence of anticipation and motor-motor task performance on cutting biomechanics. Cross-sectional study. Laboratory. A total of 32 healthy, recreationally active men (age = 23.1 ± 3.6 years, height = 180.0 ± 7.0 cm, mass = 81.3 ± 17.3 kg) who self-reported regular participation in cutting sports. Participants performed a 45° side-step cut on the dominant limb in a random order of conditions: anticipation (anticipated, unanticipated) and task (no ball throw, ball fake, ball throw). Triplanar trunk, hip, and knee angles were assessed throughout the stance phase using 3-dimensional motion capture. Data were analyzed using a time series of means calculated from initial contact to toe-off (0%-100%) with 90% confidence intervals. Mean differences between conditions were identified as regions of nonoverlapping confidence intervals, and those that occurred during the region of peak vertical ground reaction force (0%-25%) are presented. Regardless of anticipation, attending to a ball (ball throw) resulted in more trunk extension (range = 2.9°-3.7°) and less lateral trunk flexion toward the cutting direction (range = 5.2°-5.9°). Planning to attend to a ball (ball fake) resulted in less lateral trunk flexion toward the cutting direction (4.7°). During unanticipated cutting, more trunk rotation away from the cutting direction was observed when attending to a ball (range = 5.3°-7.1°). The interaction of anticipation and task had a similar influence on sagittal- and frontal-plane trunk position. Motor-motor task performance and its interaction with anticipation induced an upright, neutral trunk position during side-step cutting, which has been associated with the risk for noncontact knee injury. Promoting task complexity during rehabilitation and injury-prevention programs may better prepare individuals to succeed when performing high-risk athletic maneuvers.

Anterior cruciate ligament bundle insertions vary between ACL-rupture and non-injured knees.

The present study aimed to investigate the three-dimensional topographic anatomy of the anterior cruciate ligament (ACL) bundle attachment in both ACL-rupture and ACL-intact patients who suffered a noncontact knee injury and identify potential differences. Magnetic resonance images of 90 ACL-rupture knees and 90 matched ACL-intact knees, who suffered a noncontact knee injury, were used to create 3D ACL insertion models. In the ACL-rupture knees, the femoral origin of the anteromedial (AM) bundle was 24.5 ± 9.0% posterior and 45.5 ± 10.5% proximal to the flexion-extension axis (FEA), whereas the posterolateral (PL) bundle origin was 35.5 ± 12.5% posterior and 22.4 ± 10.3% distal to the FEA. In ACL-rupture knees, the tibial insertion of the AM-bundle was 34.3 ± 4.6% of the tibial plateau depth and 50.7 ± 3.5% of the tibial plateau width, whereas the PL-bundle insertion was 47.5 ± 4.1% of the tibial plateau depth and 56.9 ± 3.4% of the tibial plateau width. In ACL-intact knees, the origin of the AM-bundle was 17.5 ± 9.1% posterior (p < 0.01) and 42.3 ± 10.5% proximal (n.s.) to the FEA, whereas the PL-bundle origin was 32.1 ± 11.1% posterior (n.s.) and 16.3 ± 9.4% distal (p < 0.01) to the FEA. In ACL-intact knees, the insertion of the AM-bundle was 34.4 ± 6.6% of the tibial plateau depth (n.s.) and 48.1 ± 4.6% of the tibial plateau width (n.s.), whereas the PL-bundle insertion was 42.7 ± 5.4% of the tibial plateau depth (p < 0.01) and 57.1 ± 4.8% of the tibial plateau width (n.s.). The current study revealed variations in the three-dimensional topographic anatomy of the native ACL between ACL-rupture and ACL-intact knees, which might help surgeons who perform anatomical double-bundle reconstruction surgery. III.

Association between lower extremity muscular strength and acute knee injuries in young team‐sport athletes

The purpose of this study was to investigate LE muscular strength variables as potential risk factors for all and non-contact acute knee and ACL injuries in young athletes. A total of 188 young (≤21) male and 174 female basketball and floorball players participated in LE muscular strength tests and were followed up to 3 years. The strength test battery consisted of 1RM leg press, maximal concentric isokinetic (60°/s) quadriceps and hamstrings, and maximal isometric hip abductor strength. The outcomes were a new acute knee or ACL injury and a new acute non-contact knee or ACL injury. A total of 51 (17 in males and 34 in females) new acute knee injuries registered and 17 (one in males and 16 in females) of these were ACL injuries. In the adjusted Cox regression models, only lower maximal hip abduction strength (kg/kg) was significantly associated with an increased risk of all knee injuries in males (HR 1.80 [95% CI, 1.03-3.16] for 1 SD decrease in hip abduction). However, ROC curve analysis showed an area under the curve 0.66 revealing that maximal hip abduction strength test cannot be used as a screening tool for an acute knee injury in young male athletes.

There Is No Relationship Between Lower Extremity Alignment During Unilateral and Bilateral Drop Jumps and the Risk of Knee or Ankle Injury: A Prospective Study.

To investigate the association between lower extremity alignment during unilateral and bilateral drop jump tests and the risk of acute noncontact knee or ankle injuries in young team sport athletes. Prospective cohort study. A 2-dimensional video analysis was used to measure the frontal plane knee projection angle in the single-leg vertical drop jump (VDJ) and the bilateral VDJ in young team sport athletes. Out of the 364 athletes (187 male, 177 female), 189 played basketball and 175 played floorball. Six male athletes sustained knee injuries and 23 sustained ankle injuries. Frontal plane knee projection angle in the single-leg VDJ or the bilateral VDJ was not associated with ankle injuries among male athletes. No statistical analysis was performed for the knee injuries. Among female athletes, 28 sustained knee and 41 sustained ankle injuries. Frontal plane knee projection angle during the single-leg VDJ or the bilateral VDJ was not a risk factor for knee or ankle injuries. Lower extremity alignment during unilateral and bilateral drop jump tests was not associated with future noncontact knee or ankle injuries among young team sport athletes. The findings should be interpreted cautiously due to the small number of injuries. J Orthop Sports Phys Ther 2020;50(5):267-274. doi:10.2519/jospt.2020.9247.

Altered hip control during a standing knee-lift test is associated with increased risk of knee injuries.

A few prospective studies have investigated hip and pelvic control as a risk factor for lower extremity (LE) injuries. The purpose of this study was to investigate whether deficits in hip and lumbopelvic control during standing knee-lift test are associated with increased risk of acute knee and LE injuries in youth team sports. At baseline, 258 basketball and floorball players (aged 12-21years) participated in a standing knee-lift test using 3-dimensional motion analysis. Two trials per leg were recorded from each participant. Peak sagittal plane pelvic tilt and frontal plane pelvic drop/hike were measured. Both continuous and categorical variables were analyzed. New non-contact LE injuries, and match and training exposure, were recorded for 12months. Seventy acute LE injuries were registered. Of these, 17 were knee injuries (eight ACL ruptures) and 35 ankle injuries. Risk factor analyses showed that increased contralateral pelvic hike was significantly associated with knee injury risk when using categorical variable (HR for high vs low group 4.07; 95% CI 1.32-12.6). Furthermore, significant association was found between high lateral pelvic hike angles and ACL injury risk in female players (HR for high vs low group 9.10; 95% CI 1.10-75.2). Poor combined sensitivity and specificity of the test was observed. In conclusion, increased contralateral pelvic hike is associated with non-contact knee injury risk among young team sport players and non-contact ACL injuries among female players. More research to determine the role of pelvic control as a risk factor for knee injuries is needed.

방향전환 동작 시 골반 사전운동이 하지분절 운동역학적 변인에 미치는 영향

Purpose: The purpose of this study is to analyze the effect of pre-orientation of the pelvis on kinematic and kinetic variables of the lower extremity injury during 90˚SSC (side step cutting). This study is also to investigate the relationship between pelvic pre-orientation and lower extremity injury during the SSC.BR Method: Nine healthy male college students participated in this study. Three dimensional motion analyses were used to analyze the kinematic and kinematic variables of A-SSC (typical SSC) and B-SSC (SSC which suppressed pre-orientation of the pelvis) during WAP (weight acceptance phase).BR Results: The approach velocity reached to side cutting point was not significantly different between the two SSCs. Pelvic pre-orientation significantly decreased in the B-SC. The maximum ground reaction force and the location of the center of gravity significantly increased laterally in the A-SSC. Landing distance and last step length both increased with the B-SSC. The maximum angles of knee and hip were not significantly different except the valgus angle of knee joint. The knee valgus and internal rotation moment increased significantly in the A-SSC.BR Conclusion: The length of the last step increased laterally in the B-SSC, but did not increase with the valgus and internal rotation moment of the knee joint. Therefore, even if the pelvic pre-orientation is suppressed during the SSC, it does not seem to have any negative effect on the non-contact knee injury.

RELATIONSHIP BETWEEN ISOKINETIC LEG STRENGTH AND KNEE FRONTAL PLANE PROJECTION ANGLE DURING SINGLE LEG SQUAT AMONG MALE JUNIOR ATHLETES

Background: Those with increased dynamic knee valgus are vulnerable to increased risk of non-contact kneeinjuries. However, studies on the top down kinetic chain of lower limb mechanics during dynamic motionssuch as single leg squat (SLS) among trained males were scarce.Objective: The objective of the study was to evaluate the relationship between isokinetic hip and knee strengthand frontal plane projection angle (FPPA) of the knee joint during SLS.Methods: Thirty-two male junior athletes (twelve cyclists, ten runners and ten squash players) were screenedfor excessive dynamic knee valgus (DKV) prior to participation. Only those within the normal value of DKV wereincluded. Their hip and knee isokinetic strength in sagittal plane were evaluated at 60Âo/s of angular velocityfor both legs using dynamometer. Two dimensional knee FPPA was evaluated during SLS at 60Âo of knee flexion.Pearson correlation was evaluated between knee FPPA during SLS and isokinetic leg strength.Results: Correlations between knee FPPA and hip and knee isokinetic strength were not statistically significantexcept between knee flexion peak torque/body weight (r = -0.35, p = 0.05) and hamstring to quadriceps ratio(r = -0.39, p = 0.03) of non-dominant leg.Conclusions: Isokinetic hip and knee strength and knee FPPA during SLS was correlated only for non-dominantleg during SLS among male junior athletes. DKV during SLS may be reduced through strengthening the musclesaround hip and knee joints.

The Femoral Footprint Position of the Anterior Cruciate Ligament Might Be a Predisposing Factor to a Noncontact Anterior Cruciate Ligament Rupture

Background: Although the femoral tunnel position is crucial to anatomic single-bundle anterior cruciate ligament (ACL) reconstruction, the recommendations for the ideal femoral footprint position are mostly based on cadaveric studies with small sample sizes, elderly patients with unknown ACL status, and 2-dimensional techniques. Furthermore, a potential difference in the femoral ACL footprint position and ACL orientation between ACL-ruptured and ACL-intact knees has not been reported in the literature. Hypothesis: The femoral ACL footprint position and ACL orientation vary significantly between ACL-ruptured and matched control ACL-intact knees. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Magnetic resonance images of the knees of 90 patients with an ACL rupture and 90 matched control participants who had a noncontact knee injury without an ACL rupture were used to create 3-dimensional models of the femur and tibia. The ACL footprints were outlined on each model, and their positions (normalized to the lateral condyle width) as well as ACL orientations were measured with an anatomic coordinate system. Results: The femoral ACL footprint in patients with an ACL rupture was located at 36.6% posterior and 11.2% distal to the flexion-extension axis (FEA). The ACL orientation was 46.9° in the sagittal plane, 70.3° in the coronal plane, and 20.8° in the transverse plane. The ACL-ruptured group demonstrated a femoral ACL footprint position that was 11.0% more posterior and 7.7% more proximal than that of the control group (all P < .01). The same patients also exhibited 5.7° lower sagittal elevation, 3.1° higher coronal plane elevation, and 7.9° lower transverse plane deviation (all P < .01). The optimal cutoff value of the femoral ACL footprint position to prevent an ACL rupture was at 30% posterior and 12% distal to the FEA. Conclusion: The ACL femoral footprint position might be a predisposing factor to an ACL rupture. Patients with a >30% posterior and <12% distal position of the femoral ACL footprint from the FEA might have a 51.2-times increased risk of an ACL rupture.

Poor Pelvic Control During A Knee Lift Test Is Associated With Increased Risk Of Knee Injuries

PURPOSE: To investigate whether deficits in stance leg, hip and pelvic stability during a standing knee lift test are associated with increased risk of non-contact knee and ankle injuries in youth team sports. METHODS: At baseline, 263 basketball and floorball players (age range 12–21 y.) participated in a standing knee lift test using 3-dimensional motion analysis. The test was a modified version of the Trendelenburg test to assess stance leg and hip stability. Two trials per leg were recorded from each participant and mean value was used in the analysis. The biomechanical variables calculated were peak anterior pelvic tilt angle (APT) and peak lateral pelvic drop angle (LPD). The APT and LPD were categorized into two groups using the median of the cohort: low group (values less than median value) and high group (values larger than median). All new non-contact knee and ankle injuries, as well as match and training exposure, were then recorded for 12 months. Cox regression models were used to calculate hazard ratios (HRs) and 95% CIs. RESULTS: A total of 16 new non-contact knee injuries (of which eight were ACL ruptures, all affecting female players) and 36 new non-contact ankle injuries were registered during the study period. Athletes displaying high lateral pelvic drop angles were at increased risk of knee injuries (adjusted HR for high versus low group 4.22; 95% CI 1.34–13.3). A borderline significant (p=0.05) association was found between high lateral pelvic drop angles and ACL injury risk in female athletes (adjusted HR for high versus low group 8.14; 95% CI 0.97–68.6). No potential ankle injury risk factors were found. A receiver operating characteristic curve analysis for the LPD and knee injuries showed an area under the curve of 0.60, which indicates poor combined sensitivity and specificity of the test. CONCLUSIONS: Poor pelvic control, with increased lateral pelvic drop, is associated with increased risk of non-contact knee injuries among young team sport players. However, the knee lift test cannot predict non-contact knee injuries in youth team sports. Supported by the Finnish Ministry of Education and Culture, and Competitive State Research Financing of the Expert Responsibility area of Tampere University Hospital (Grant 9S047).

Dynamic knee control and movement strategies in athletes and non-athletes in side hops: Implications for knee injury.

Athletes exposed to rapid maneuvers need a high level of dynamic knee stability and robustness, while also controlling whole body movement, to decrease the risk of non‐contact knee injury. The effects of high‐level athletic training on such measures of movement control have not, however, been thoroughly evaluated. This study investigated whether elite athletes (who regularly perform knee‐specific neuromuscular training) show greater dynamic knee robustness and/or different movement strategies than non‐athletic controls, in relation to overall knee function. Thirty‐nine women (19 athletes, 20 controls) performed standardized rebound side hops (SRSH) while a motion capture system synchronized with two force plates registered three‐dimensional trunk, hip, and knee joint angles and moments. Dynamic knee robustness was evaluated using finite helical axis (FHA) inclination angles extracted from knee rotation intervals of 10°, analyzed with independent t tests. Angle and moment curves were analyzed with inferential methods for functional data. Athletes had superior knee function (less laxity, greater hop performances, and strength) but presented similar FHA inclination angles to controls. Movement strategies during the landing phase differed; athletes presented larger (a) hip flexion angles (during 9%‐29% of the phase), (b) hip adduction moments (59%‐99%), (c) hip internal rotation moments (83%‐89%), and (d) knee flexion moments (79%‐93%). Thus, elite athletes may have a greater ability than non‐athletes to keep the knee robust while performing SRSH more efficiently through increased engagement of the hip. However, dynamic knee robustness associated with lower FHA inclination angles still show room for improvement, thus possibly decreasing knee injury risk.

Knee Ultrasonography to Determine Risk for Noncontact Injuries in Collegiate American Football Players.

Knee ultrasonography has been used effectively as a screening tool for determining risk for knee injuries in athletes. Ultrasonography may be a valuable screening tool for relative risk of noncontact knee injuries that occur over a typical playing career in collegiate American football players. In this prospective longitudinal study, we evaluated American football players (n = 48) in an academic institution affiliated with the National Collegiate Athletic Association Division I athletic program. Players underwent comprehensive ultrasonography of both knees prior to beginning their collegiate careers. Anatomic structures were evaluated for presence and severity of abnormalities. Noncontact lower extremity injuries sustained over the collegiate career of the subjects were documented. Data were analyzed for correlations, differences in proportions, and odds ratio (OR). Seventy-nine percent of the athletes had at least one ultrasonographic abnormality, with quadriceps tendon (47.9%) and patellar tendon (39.6%) abnormalities predominating. Seventy-nine percent of players had at least one noncontact lower extremity injury (23.5% involving the knee) during their careers with an average of 2.8 injuries per career. The majority of injuries occurred in the second and third playing years. There was a significantly higher likelihood of patellar tendon injury based on the presence of patellar tendon ultrasonographic pathology (p = 0.024; OR = 11x). There was a significantly higher likelihood of quadriceps muscle-tendon injury based on the presence of quadriceps tendon ultrasonography pathology (p = 0.0012; OR = 140x). All athletes sustaining meniscal injuries had preexisting joint effusion but no preexisting ultrasonographic meniscal pathology. Knee ultrasonography along with patient history and complete physical examination may help reduce injury risk through education, prevention, and training programs.

Cruciate ligament healing and injury prevention in the age of regenerative medicine and technostress: homeostasis revisited.

This clinical concepts paper discusses the essential elements of cruciate ligament recuperation, micro-trauma repair, and remodeling. Cruciate ligament mechanobiology and tissue heterogeneity, anatomy and vascularity, and synovial membrane and fluid functions are discussed in relationship to deficiency-induced inflammatory responses, nervous and immune system function, recuperation, repair and remodeling, and modern threats to homeostasis. Cruciate ligament surgical procedures do not appreciate the vital linked functions of the central, peripheral, and autonomic nervous systems and immune system function on knee ligament injury recuperation, micro-trauma repair, and remodeling. Enhanced knowledge of these systems could provide innovative ways to decrease primary non-contact knee injury rates and improve outcomes following reconstruction or primary repair. Restoration of knee joint homeostasis is essential to cruciate ligament recuperation, micro-trauma repair, and remodeling. The nervous and immune systems are intricately involved in this process. Varying combinations of high-intensity training, under-recovery, technostress, and environmental pollutants (including noise) regularly expose many athletically active individuals to factors that abrogate the environment needed for cruciate ligament recuperation, micro-trauma repair, and remodeling. Current sports training practice, lifestyle psychobehaviors, and environmental factors combine to increase both primary non-contact knee injury risk and the nervous and immune system dysregulation that lead to poor sleep, increased anxiety, and poorly regulated hormone and cytokine levels. These factors may create a worst-case scenario leading to poor ligament recuperation, micro-trauma repair, and remodeling. Early recognition and modification of these factors may decrease knee ligament injury rates and improve cruciate ligament repair or reconstruction outcomes. V.

Kinematic effects of repeated turns while running

In team sports, non-contact ACL and MCL injuries occur during abrupt changes of direction, like turns or cutting manoeuvres. Fatigue affects dynamic neuromuscular control and increases knee injury risk. This study analysed how lower limb joints and centre-of-mass kinematics are affected throughout a high-intensity running protocol involving repeated 180°-turns. Twenty young men (18–23 years, BMI: 20.8–24.4 kg m−2) completed a 5-m shuttle running trial lasting 5 min at an average speed of 75% of their maximum aerobic speed. During the test, cardio-metabolic parameters were obtained, together with joints and centre-of-mass kinematics, using a motion capture system. Kinematic data were compared between the first and the last minute of exercise. Perceived exercise intensity ranged from “hard” to “maximum exertion” and post-exercise lactate concentration ranged from 5.4 to 15.5 mM. The repetition of 180°-turns induced a substantial reduction of hip (−60%, p < .001, large effect) and knee flexion (−40%, p = .003, medium-to-large effect), and an increase of hip adduction and internal rotation (+25–30%, p < .05, medium-to-large effect). Since such movements are factors increasing the likelihood of non-contact knee injuries, we concluded that the prolonged repetition of turns may expose participants to increased risk of ligament failure. Prevention programmes should include discipline-specific neuromuscular training especially in late practices.

RELIABILITY OF A NEW LANDING ERROR SCORING SYSTEM: THE LESS-RMC

BACKGROUND Several biomechanical deficits have been shown to increase non-contact knee injury risk of the anterior cruciate ligament (ACL). The Landing Error Scoring System (LESS) is a clinical assessment tool that has been successfully used to predict the individuals that are at a high risk for injury and evaluate changes in landing technique after participation in a neuromuscular preventive training program. The LESS-RT is a shortened version of the LESS and is a method to score landing technique without the use of video. The current study proposes a new tool for the evaluation of landing technique and ACL injury risk that blends the LESS and LESS-RT protocols but emphasizes the movement features that contribute to high knee valgus moments including movement asymmetry. The LESS-RMC (Rocky Mountain Consortium) consists of evaluating 11 comprehensive landing errors that are related to ACL injury risk. Consolidating questions pertaining to the opposite ends of joint motion such as “toe in” and “toe out” into “maximum foot rotation position” and adding a global asymmetry score were performed to reduce the time demands for evaluation yet capture the salient factors of the LESS; whereas the penalty for knee valgus severity was pulled from the LESS-RT but implemented for both knees in the new LESS-RMC to ultimately stratify knee injury risk during the jump landing task. The purpose of this study was to determine the reliability of the new LESS-RMC assessment tool. METHODS Thirty-seven, elite female soccer athletes (13.2 +/- 0.4 y) performed three drop-jumps from a height of 30 cm. Front and side views of the landing were recorded with digital video cameras. Movement quality was rated by 4 researchers evaluating 17 components of the landing with the LESS and a modified, 11 component version of the LESS (LESS-RMC). The 4 raters were novel to the evaluation of both scoring systems. Each rater was trained how to score each test and was instructed to evaluate the landing trials from the first 10 participants. After a group video review and discussion, the raters repeated the scoring procedures for the same 10 participants 48 hours after the original review. After another 48 hours, the raters evaluated the landing trials for all 37 participants (111 trials). Inter-rater reliability of the LESS and LESS-RMC were determined using the ICC (3,1) equations and the output from a two-way ANOVA (SPSS, version 25). RESULTS The mean LESS score was 6.45 +/- 0.55 (rater 1, 6.42; rater 2, 7.15; rater 3, 5.79; rater 4, 6.45). The ICC agreement between raters of scoring the LESS was .389 whereas the ICC agreement for the mean of the four raters was .718. The ICC for scoring consistency was .382 and Cronbach’s a was .735. The mean LESS-RMC score was 6.19 +/- 0.74 (rater 1, 5.65; rater 2, 6.99; rater 3, 5.48; rater 4, 6.64). The ICC agreement of scoring the LESS-RMC was .585 whereas the ICC agreement for the mean of the four raters was .849. The ICC for scoring consistency was .574 and Cronbach’s a was .884. CONCLUSION On average, the raters scored the LESS and the LESS-RMC with moderate reliability across the group of athletes. The LESS-RMC was scored with greater reliability than the LESS for this group of relatively novice raters. This is likely due to the simplification of the overall protocol in terms of quantity of questions, the ability of a novel rater to understand scenarios which elicit specific scores and the clear separation of body segments (e.g. hip and trunk flexion). In conjunction with this, it was reported by the raters that LESS-RMC was less redundant and more effective at assessing crucial aspects of a jump landing pattern. Overall, LESS RMC was objectively and subjectively more reliable and easier to use than the LESS for the four raters involved in this study. It is concluded that the LESS-RMC is a quick, easy and reliable clinical assessment tool that may be used to stratify individuals who may be at risk for ACL injury.

National Athletic Trainers' Association Position Statement: Prevention of Anterior Cruciate Ligament Injury.

To provide certified athletic trainers, physicians, and other health care and fitness professionals with recommendations based on current evidence regarding the prevention of noncontact and indirect-contact anterior cruciate ligament (ACL) injuries in athletes and physically active individuals. Preventing ACL injuries during sport and physical activity may dramatically decrease medical costs and long-term disability. Implementing ACL injury-prevention training programs may improve an individual's neuromuscular control and lower extremity biomechanics and thereby reduce the risk of injury. Recent evidence indicates that ACL injuries may be prevented through the use of multicomponent neuromuscular-training programs. Multicomponent injury-prevention training programs are recommended for reducing noncontact and indirect-contact ACL injuries and strongly recommended for reducing noncontact and indirect-contact knee injuries during physical activity. These programs are advocated for improving balance, lower extremity biomechanics, muscle activation, functional performance, strength, and power, as well as decreasing landing impact forces. A multicomponent injury-prevention training program should, at minimum, provide feedback on movement technique in at least 3 of the following exercise categories: strength, plyometrics, agility, balance, and flexibility. Further guidance on training dosage, intensity, and implementation recommendations is offered in this statement.