Risk Factors For Anterior Cruciate Ligament Injury Research Articles

Relationship Between Anterior Knee Laxity and General Joint Laxity During the Menstrual Cycle.

Background:Anterior cruciate ligament (ACL) injury has been reported to have a higher incidence in women than in men.Purpose/Hypothesis:The purpose was to examine the relationship of anterior knee laxity (AKL), stiffness, and generalized joint laxity (GJL) with respect to the menstrual cycle. It was hypothesized that AKL and GJL would increase during the ovulation phase, when estrogen levels are high.Study Design:Descriptive laboratory study.Methods:A total of 15 female university students aged >20 years and with normal menstrual cycles were evaluated. AKL was measured as anterior tibial displacement of the femur after application of 44-, 89-, and 133-N loads to the tibia. Stiffness was calculated as Δ force/Δ displacement at loads between 44 and 89 N and between 89 and 133 N. The University of Tokyo joint laxity test was used for evaluation of GJL. The participants’ menstrual cycle was divided into the early follicular, late follicular, ovulation, and luteal phases using the basal body temperature method and an ovulation kit; AKL and GJL were measured once during each phase. Participants were also stratified according to the presence or absence of genu recurvatum (GR).Results:There was no significant difference in AKL, stiffness, or GJL among the menstrual phases. In the GR group, AKL values at 89 N and 133 N were significantly higher in the ovulation phase than in the early follicular phase (P = .025 and P =.018, respectively); there were no significant differences in AKL among the phases in the non-GR group. In addition, the GR group in the ovulation phase had significantly higher AKL values at 44 N, 89 N, and 133 N compared with the non-GR group (P = .013, P = .005, and P = .010, respectively). There were no significant differences in GJL among the phases in the GR or non-GR groups.Conclusion:Women with GR may have increased AKL in the ovulation phase when compared with the early follicular phase, which may be a risk factor for ACL injury.Clinical Relevance:The results of this study suggest that the ovulation phase may be related to the greater incidence of ACL injuries in women.

Does delayed onset muscle soreness affect the biomechanical variables of the drop vertical jump that have been associated with increased ACL injury risk? A randomised control trial.

Delayed onset muscle soreness (DOMS) and Anterior Cruciate Ligament (ACL) injuries are both prevalent in sport. It is currently unknown whether DOMS increases ACL injury risk. This study aimed to provide preliminary insight on whether DOMS affects ACL injury risk by investigating whether DOMS affects the biomechanical variables of the DVJ that have been identified as risk factors for future ACL injury. This was a randomised control trial involving 32 active individuals aged 18-35years, with no history of ACL injury. Participants underwent two sessions of force-plate testing and 3D motion analysis of the drop vertical jump (DVJ). The DVJ was chosen as it has been investigated prospectively for association with future ACL injury. Initial testing was followed by randomisation to DOMS or control group. The DOMS group underwent a DOMS-inducing exercise protocol, the control group did not. Both groups were re-tested 48h after initial testing. Five variables of the DVJ that have been associated with future ACL injury were chosen for analysis - peak knee flexion angle, peak vertical ground reaction force, ground contact time, peak knee abduction angle & peak knee abduction moment. Between-group differences were compared using a two-way mixed analysis of variance; alpha level set to 0.05. DOMS was successfully induced in all participants of the DOMS group however no statistically significant group x time interactions were found for any of the five variables analysed. DOMS did not affect the biomechanical variables of the DVJ that have been associated with future ACL injury. By extension, this may suggest that DOMS might not affect ACL injury risk. However, it is also possible that certain attributes of the DVJ meant that any effect of DOMS was simply unable to be quantified, even if an effect existed. All considered, our position is that conclusion cannot be drawn from this study alone on whether DOMS affects ACL injury risk. Further research is required.

Relationship of Anterior Cruciate Ligament Volume and T2* Relaxation Time to Anterior Knee Laxity.

Background:High anterior knee laxity (AKL) has been prospectively identified as a risk factor for anterior cruciate ligament (ACL) injuries. Given that ACL morphometry and structural composition have the potential to influence ligamentous strength, understanding how these factors are associated with greater AKL is warranted.Hypothesis:Smaller ACL volumes combined with longer T2* relaxation times would collectively predict greater AKL.Study Design:Cross-sectional study; Level of evidence, 3.Methods:College-aged active male (n = 20) and female (n = 30) participants underwent magnetic resonance imaging (MRI) and AKL testing. T2-weighted MRI scans were used to assess ACL volumes, and T2* relaxation times were used to assess ACL structural composition. AKL was measured via a commercial knee arthrometer. Forward stepwise linear regression with sex and weight (first step; suppressor variables) as well as ACL volume and T2* relaxation time (second step; independent variables) was used to predict AKL (dependent variable).Results:After initially adjusting for sex and weight (R 2 = 0.19; P = .006), smaller ACL volumes combined with longer T2* relaxation times collectively predicted greater AKL (R 2 = 0.52; P < .001; R 2 Δ = 0.32; P Δ < .001). A smaller ACL volume was the primary predictor of greater AKL (R 2 Δ = 0.28; P < .001), with a longer T2* relaxation time trending toward a significant contribution to greater AKL (R 2 Δ = 0.04; P = .062). After adjusting for ACL volume and T2* relaxation time, sex (partial r = 0.05; P = .735) and weight (partial r = 0.05; P = .725) were no longer significant predictors.Conclusion:AKL was largely predicted by ACL volume and to a lesser extent by T2* relaxation time (and not a person’s sex and weight). These findings enhance our understanding of how AKL may be associated with a structurally weaker ACL. The current study presents initial evidence that AKL is a cost-effective and clinically accessible measure that shows us something about the structural composition of the ACL. As AKL has been consistently shown to be a risk factor for ACL injuries, work should be done to continue to investigate what AKL may tell a clinician about the structure and composition of the ACL.

Long-term Effect of a Single Subcritical Knee Injury: Increasing the Risk of Anterior Cruciate Ligament Rupture and Osteoarthritis

Background: Rupture of the anterior cruciate ligament (ACL) is a well-known risk factor for the development of posttraumatic osteoarthritis (PTOA), but patients with the “same injury” can have vastly different trajectories for the onset and progression of disease. Minor subcritical injuries preceding the critical injury event may drive this disparity through preexisting tissue pathologies and sensory changes. Purpose: To investigate the role of subcritical injury on ACL rupture risk and PTOA through the evaluation of pain behaviors, joint mechanics, and tissue structural change in a mouse model of knee injury. Study Design: Controlled laboratory study. Methods: Ten-week-old male C57BL/6J mice were allocated to naïve control and subcritical knee injury groups. Injury was induced by a single mechanical compression to the right hindlimb, and mice were evaluated using joint histopathology, anteroposterior joint biomechanics, pain behaviors (mechanical allodynia and hindlimb weightbearing), and isolated ACL tensile testing to failure at 1, 2, 4, or 8 weeks after injury. Results: Subcritical knee injury produced focal osteochondral lesions in the patellofemoral and lateral tibiofemoral compartments with no resolution for the duration of the study (8 weeks). These lesions were characterized by focal loss of proteoglycan staining, cartilage structural change, chondrocyte pathology, microcracks, and osteocyte cell loss. Injury also resulted in the rapid onset of allodynia (at 1 week), which persisted over time and reduced ACL failure load (P = .006; mean ± SD, 7.91 ± 2.01 N vs 9.37 ± 1.01 N in naïve controls at 8 weeks after injury), accompanied by evidence of ACL remodeling at the femoral enthesis. Conclusion: The present study in mice establishes a direct effect of a single subcritical knee injury on the development of specific joint tissue pathologies (osteochondral lesions and progressive weakening of the ACL) and allodynic sensitization. These findings demonstrate a predisposition for secondary critical injuries (eg, ACL rupture) and an increased risk of PTOA onset and progression (structurally and symptomatically). Clinical Relevance: Subcritical knee injuries are a common occurrence and, based on this study, can cause persistent sensory and structural change. These findings have important implications for the understanding of risk factors of ACL injury and subsequent PTOA, particularly with regard to prevention and management strategies following an often underreported event.

Femoral notch and proximal tibial morphology and their relationship with an anterior cruciate ligament injury in the Indian population: A magnetic resonance imaging-based study

Objectives: We aim to study the incidence of anterior cruciate ligament (ACL) injury to proximal tibia bone morphology in Indian patients. Materials and Methods: Forty male subjects who sustained non-contact ACL injury who presented to our center between October 2015 and December 2016 studied and compared to 40 non-ACL injury knee magnetic resonance imaging scans. Notch morphology and both medial and lateral posterior tibial slope measurements were performed and studied. Results: We noted that the difference in notch depth and notch angle between the two groups was not significant. There was a statistically significant higher incidence of ACL injury in patients with smaller notch widths. Both an increased medial and lateral posterior tibial slope did not demonstrate a statistically significant incidence in ACL injury. Conclusion: Notch width is a major contributing risk factor for ACL injury in Indian patients. This is in agreement with previously published literature.

Effects of pelvic and core strength training on biomechanical risk factors for anterior cruciate ligament injuries.

Little is known about the changes in biomechanical risk factors for an anterior cruciate ligament (ACL) injury after participation in a pelvic and core strength training (PCST) program in female team players. This is a randomized controlled trial for which a total of 29 female soccer players were recruited from a soccer club and split into two groups, namely, experimental group (EG, N.=18; mean [SD] age, 17.8 [2.0 years], weight 64.0 [6.6] kg and height 1.7 [0.0] m) and control group (control, N.=11; mean [SD] age, 16.2 [1.2] years, weight 61.6 [7.3] kg and height 1.7 [0.0] m). The EG participated in an in-season 8-week PCST program (twice/week). Participants in the CG performed their normal training without additional pelvic and core strengthening. Pre- and postintervention knee frontal plane projection angle (FPPA), hip, knee and ankle peak flexion angles and jump height were collected during bilateral and unilateral drop jumps. PCST significantly reduced FPPA at dynamic landing, in both dominant (-7.1º) and non-dominant lower extremities (-8º). Further, this training significantly increased the peak hip (24.4º) and knee flexion angles (14.94º), but not the peak ankle dorsiflexion angle (P>0.05) which, significantly decreased in the CG (-3.5º). Following the intervention, EG significantly increased measures obtained for both bilateral (2.84 cm) and unilateral jumps (1.33 cm for the dominant leg and 1.22 cm for the non-dominant leg) (P<0.05), not so for CG (P<0.05). PCST resulted in improvements on ACL injury risk factors and vertical drop jump performance, suggesting that strengthening this body part warrants not only injury prevention, but increases jumping performance.

Association between ankle angle at initial contact and biomechanical ACL injury risk factors in male during self-selected single-leg landing

BackgroundIncreasing the ankle plantar-flexion angle at initial contact (IC) during landing reduces the impact features associated with landing, such as the vertical ground reaction force and loading rate, potentially affecting the risk of anterior cruciate ligament (ACL) injury. However, the relationships between the ankle plantar-flexion angle at IC and the previously identified biomechanical factors related to noncontact ACL injury have not been studied. Research questionThus, the purpose of this study was to determine whether significant relationships exist between the ankle plantar-flexion angle at IC and the biomechanical factors related to noncontact ACL injury. MethodsThe peak anterior tibial shear force, peak external knee valgus moment, peak knee valgus angle, and combined peak external knee valgus plus tibial internal rotation moments were measured in 26 individuals while performing self-selected, single-leg landing. Pearson correlation analyses were performed to assess the relationships between the ankle plantar-flexion angle at IC and the biomechanical factors mentioned above. ResultsThe greater ankle plantar-flexion angle at IC was related to smaller the peak knee valgus moment (r = −0.5, p = 0.009) and the combined peak knee valgus plus internal rotation moments (r = −0.58, p = 0.001). SignificanceThese results suggest that large ankle plantar-flexion angle at IC might be associated with lesser loading of the knee frontal plane and altering the self-selective ankle angle may result in biomechanical changes associated with ACL injury risk.

Risk factors for noncontact anterior cruciate ligament injury in female high school basketball and handball players: A prospective 3-year cohort study

IntroductionThe risk factors of noncontact anterior cruciate ligament (ACL) injury remain an enigma. The purpose of this study was to prospectively evaluate the risk factors for noncontact ACL injury in female high school basketball and handball players. Materials and MethodsWe conducted a 3-year prospective cohort study between 2009 and 2014, and it included 317 female high school athletes aged 15 years. At baseline, they underwent detailed examinations for various parameters that were documented during their first year of high school. The parameters assessed were height (cm), weight (kg), general joint laxity (points), navicular drop (mm), anterior laxity of the knee using the KT-1000 Knee Ligament Arthrometer (mm), angle of femoral anteversion (º), knee extensor/flexor muscle strength (Nm/kg), and hip abductor strength (Nm/kg). All ACL injuries that occurred during these 3 years were recorded. ResultsOf 317 players, 27 were excluded because they either had a history of ACL injury or could not complete the study. Thirty ACL tears occurred. Three of the ACL injuries were contact injuries, whereas the remaining 27 were noncontact injuries. Greater body weight (95% confidence interval [CI], 1.030–1.174; P = 0.004), a high hip abductor strength (95% CI, 1.462–4.827; P = 0.001), and small femoral anteversion (95% CI, 0.746–0.982; P = 0.027) were found to be risk factors in logistic regression analysis. ConclusionGreater body weight, a high hip abductor strength, and small femoral anteversion were risk factors for noncontact ACL injury in female high school basketball and handball players.

Higher risk of contralateral anterior cruciate ligament (ACL) injury within 2years after ACL reconstruction in under-18-year-old patients with steep tibial plateau slope.

To assess the role of Tibial Plateau Slope (TPS) as risk factor for early Anterior Cruciate Ligament (ACL) reconstruction failure and contralateral ACL injury in a population of patients with less than 18years of age and operated on with the same surgical technique. Ninety-four consecutive patients (mean age 15.7 ± 1.5years) with at least 2years of follow-up, who underwent ACL reconstruction with a single-bundle plus lateral-plasty hamstring technique in the same centre were included. Subsequent ACL injuries (ipsilateral ACL revision or contralateral ACL reconstruction) were assessed within the first 2years after surgery. Anterior, central, posterior TPS of medial compartment were measured on lateral radiographs and compared between patients with intact graft and those with a second injury. Cut-off values with sensitivity and specificity were calculated with receiver operating characteristic (ROC) analysis. Survival analysis for second ACL injuries and multivariate analysis were performed. Eight patients (9%) had ipsilateral ACL Revision and eight patients (9%) had contralateral ACL reconstruction. Patients with contralateral injury had a higher Central TPS with respect to those without second injury (12.6° ± 2.8° vs 9.3° ± 3.7°, p = 0.042). No differences were present in patients with ipsilateral ACL revision. Sensitivity and specificity for central TPS slope ≥ 12° to detect a contralateral rupture were 63% and 75% (p = 0.0092), for Anterior TPS were 100% and 52% (p = 0.0009). Patients with TPS values exceeding these cut-offs had higher rate of contralateral ACL injuries (19%vs4%, p = 0.0420) and lower 2-year survival (p = 0.0049). Multivariate analysis identified pre-operative sport level and TPS (either anterior or central) as risk factors for contralateral injuries. Steep tibial plateau slope ≥ 12° is associated with a higher risk of contralateral ACL injury within 2years after ACL reconstruction in patients less than 18years of age. However, TPS has no role in early ipsilateral re-injury after combined ACL reconstruction and lateral plasty. The clinical relevance is that both the surgeon and the patient should be aware of this higher risk and consider it in the rehabilitation phase to reduce the incidence of such injuries. III.

Sex-based differences in landing mechanics vary between the drop vertical jump and stop jump

The purpose of the present study was to compare landing mechanics between the stop jump (SJ) and drop vertical jump (DVJ) and to compare sex-based differences in landing mechanics between tasks. 50 healthy recreational athletes were recruited and each participant completed seven SJs and seven DVJs. Peak knee flexion and abduction angle, knee flexion and ab/adduction range of motion (ROM), peak vertical and posterior ground reaction force (GRF), peak internal knee extension and knee adduction moment were computed for the dominant limb during the first landing of both tasks. A two-way ANOVA was used to determine the effects of and interactions between sex (men vs women) and task (SJ vs DVJ) for each outcome. There was an interaction for peak vertical GRF (p = 0.024), knee flexion ROM (p = 0.027), knee ab/adduction ROM (p = 0.047), and peak knee flexion (p = 0.034) and adduction (p = 0.012) moment. The SJ resulted in smaller vertical GRFs, larger posterior GRFs, and larger peak internal knee adduction moments relative to the DVJ (all p < 0.002). Women landed with larger peak knee abduction angles, larger internal knee adduction moments, and smaller knee extension moments relative to men (p = 0.001–0.026). Overall, as the SJ resulted in larger posterior GRFs and internal knee adduction moments, this task produced movements which resemble most anterior cruciate ligament (ACL) injuries and are risk factors for ACL injuries. As the SJ produced more sex-based differences, it may be better suited than the DVJ for ACL injury risk screening. This study therefore stressed the importance of selecting an appropriate landing task for ACL injury prevention research and clinical return to sport assessment.

Do Looks or Measurements Really Matter When It Comes to ACL Tears?: Commentary on an article by Steve Bayer, BA, et al.: "Knee Morphological Risk Factors for Anterior Cruciate Ligament Injury. A Systematic Review".

Do Looks or Measurements Really Matter When It Comes to ACL Tears?: Commentary on an article by Steve Bayer, BA, et al.: "Knee Morphological Risk Factors for Anterior Cruciate Ligament Injury. A Systematic Review".

Correlation analysis between femoral trochlear dysplasia and anterior cruciate ligament injury based on CT measurement.

Anterior cruciate ligament (ACL) injury is the most common knee ligament injury. Femoral trochlear dysplasia (FTD) is an anatomic deformity characterized by a shallow trochlear angle and depth. There is limited research on the correlation between ACL injury and trochlear dysplasia. A total of 423 patients with an ACL injury who underwent ACL reconstruction and plain computed tomography (CT) follow-up scan one week after the operation in our hospital between January 2017 and March 2019 were enrolled in this study. A total of 352 patients (369 knees) without ACL injury served as a control group. The sulcus angle, trochlear facet asymmetry, trochlear depth, and lateral trochlear inclination were measured at 3 cm above the tibiofemoral joint. The notch width index (NWI) was measured on the CT axis, and the FTD was divided into four types according to the Dejour classification. The prevalence of FTD was significantly higher in the ACL injury group than in the control group (30.7% vs. 14.4%, χ2=30.834, P<0.001). The trochlear sulcus angle was higher, while the trochlear facet asymmetry and lateral trochlear inclination were significantly lower in the ACL injury group than in the control group (P<0.01). The NWI was 0.232 in the ACL injury group and 0.245 in the control group (P<0.01). In the ACL injury group, the NWI of patients with FTD was slightly smaller than that of the patients without FTD (P<0.01). Our findings indicate that FTD might be a significant risk factor for ACL injury. Whether FTD is related to ACL injury caused by smaller intercondylar notch needs further study.

Differences in anterior cruciate ligament injury risk factors between female dancers and female soccer players during single- and double-leg landing

The purpose of this study was to compare anterior cruciate ligament (ACL) injury risk factors between female dancers and female soccer players during single- and double-leg drop landing vertical jump tasks. Fifteen elite female soccer players and 45 professional female dancers (15 ballet, 15 modern, and 15 Korean dancers) were recruited to participate in this study. ACL injury risk factors were obtained from motion and ground reaction force data. Two-way repeated measure of analyses of variance (participant groups and landing tasks, 4 × 2) were used. The female dancers landed with a significantly lower trunk flexion, trunk external rotation, knee external rotation, and knee valgus moment than the female soccer players. In addition, the single-leg drop landing task demonstrated higher trunk external rotation and knee valgus moment than the double-leg drop landing vertical jump task. The female dancers had lower ACL injury risk factors than the female soccer players during landing tasks. The single-leg drop landing task is statistically correlated with ACL injury risk factors compared with double-leg drop landing vertical jump task in all groups. Le but de cette étude était de comparer les facteurs de risque de lésion du ligament croisé antérieur (LCA) entre les danseuses et les footballeuses lors de tâches de saut vertical à une ou deux jambes. Quinze joueuses de football d’élite et 45 danseuses professionnelles (15 danseuses, 15 danseuses modernes et 15 danseuses coréennes) ont été recrutées pour participer à cette étude. Les facteurs de risque de lésion du LCA ont été obtenus à partir des données de force de réaction au sol et au mouvement. Des mesures répétées d’analyses de variance (groupes de participants et tâches d’atterrissage, 4 × 2) ont été utilisées. Les danseuses ont atterri avec une flexion du tronc, une rotation externe du tronc, une rotation externe du genou et un valgus du genou significativement plus faible que les footballeuses. En outre, la tâche d’atterrissage en chute libre sur une jambe a démontré une rotation externe du tronc et un moment valgus au genou plus élevé que la tâche de saut vertical en atterrissage en chute double. Les femmes danseuses présentaient des facteurs de risque de lésion du LCA plus faibles que les footballeuses lors des tâches d’atterrissage. La tâche d’atterrissage en chute libre sur une jambe est statistiquement corrélée aux facteurs de risque de lésion du LCA par rapport à la tâche de saut vertical en atterrissage en chute double pour tous les groupes.

Knee Morphological Risk Factors for Anterior Cruciate Ligament Injury: A Systematic Review.

Anterior cruciate ligament (ACL) reconstruction incidence has increased substantially in the past 25 years. Recently, there has been a focus on knee morphology as a contributor to ACL injury risk. The purpose of this study was to systematically review the literature to assess the influence of knee morphology on ACL injury. In accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, PubMed, Embase, and MEDLINE were searched in September 2017 for studies reporting on knee morphology and ACL injury. The search was updated in June 2018. The following inclusion criteria were used: English language; full text available; Level-I, II, or III evidence; human studies; and skeletally mature patients. After systematically screening 6,208 studies, 65 studies met the inclusion/exclusion criteria. Three additional studies were identified in the search update, for a total of 68 studies comprising 5,834 ACL-injured knees. Intercondylar notch stenosis, most commonly defined by an "A-shaped" notch, decreased notch width, or decreased notch width index, was the most commonly reported femoral morphological risk factor for ACL injury. Increased femoral condylar offset ratio (>63%) and decreased condylar radius of curvature also were associated with an increased risk of ACL injury. Increased medial and lateral tibial slopes were the most commonly reported tibial risk factors. A smaller tibial eminence, reduced ACL size, and poor tibiofemoral congruity were also associated with increased injury risk. Intercondylar notch stenosis, variations in sagittal condylar shape, increased tibial slope, reduced tibial eminence size, poor tibiofemoral congruity, and reduced ACL size are substantial risk factors for ACL injury. In future research, it would be valuable to identify a slope beyond which slope correction should be performed concomitantly with ACL reconstruction, and to determine whether an optimal relationship of notch size to graft size exists. To achieve optimal outcomes, the osseous morphological risk factors should be considered in individualized anatomic ACL reconstructions. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

The relationship between anterior cruciate ligament injuries and posterior tibial slope

Background: An injury to the anterior cruciate ligament (ACL) is a multifactorial injury and is influenced by intrinsic and extrinsic risk factors. Recently, study of variable anatomy of the proximal tibia has come up as a possible risk factor for an ACL injury. Increased posterior tibial slope (PTS) has been identified as a potential risk factor for anterior cruciate ligament (ACL) injury, but studies which have examined this relationship are inconclusive and sometimes results are contradictory. Methodology: In this study sample size of total 72 patients was included, in which 38 patients had non-contact ACL injury and rest 34 constituted as a control group, who has same demographic characteristics as patients in ACL injury group. This study was conducted in period of April 2017 – Feb 2019 at tertiary care hospital, R.L. Jalappa Hospital, Sduaher, Tamaka, Kolar. All patients included in the study were above 18 years of age and also were willing to participate in the study. Patients with open injury of ipsilateral knee and with previous history of surgery over knee were excluded from the study. The posterior tibial slope was measured from a lateral knee radiograph in all the 72 cases. The data was analyzed for the association between an increased posterior tibial slope and the incidence of ACL injury. Results: In injured group of 38 patients, 15 patients were female and 23 were male. The average age of the patients in this group was 26.7 years (±6.3 years). The control group consisted of 34 patients, in which 24 were men and10 were women. The average age of the control group was 26.2 years (±6.5 years). An ANOVA revealed significant differences in tibial slope angle between the 2 groups. Subjects in the noncontact ACL group had significantly greater tibial slope angles (8.81° ± 2.58°) when compared with control subjects (6.9° ± 2.67°). The trend toward greater tibial slope angles in the noncontact ACL group was also observed when each gender was examined independently; however, the difference was only statistically significant for women between the injury and control groups (8.9° ± 2.6° vs 7.2° ± 2.4°). Conclusion: Our results concluded that, in patients who had non contact ACL injury, had increased posterior tibial slope. But despite of these findings, the clinical significance of an increased tibial slope as an isolated risk factor for ACL injury still remains unanswered. The question also remains as to what degree of increased tibial slope should raise concerns about the increased risk for subsequent injury. Limitations of this study were less number of cases and the study included only non contact ACL injuries. Thus, a study with more number of subjects and also comprising of contact ACL injuries, probably give a better conclusion. Level of evidence: Case-control retrospective study; Level III.

Biomechanical and neuromuscular comparison of single- and multi-planar jump tests and a side-cutting maneuver: Implications for ACL injury risk assessment

BackgroundNon-contact anterior cruciate ligament (ACL) injuries are a major problem among adolescent female soccer and handball players. Therefore, the aim of this study was to examine if known biomechanical and neuromuscular ACL injury risk factors obtained from single-planar jump-landings and multi-planar side-jumps can resemble the demands of side-cutting maneuvers, a known high-risk ACL injury movement for this population. MethodsTwenty-four female soccer and handball players (mean ± SD: age: 17 ± 1 year; height: 172 ± 66 cm; mass: 67 ± 9 kg) performed a series of functional tasks including two single-planar jump-landings, two multi-planar side-jumps and a sports-specific side-cutting maneuver on their dominant leg. Frontal and sagittal plane knee and hip joint kinematics and kinetics were calculated from three-dimensional motion analysis, whereas hamstring and quadriceps muscle pre-activity levels were measured with surface electromyography. ResultsThe sports-specific side-cut was distinguished by more knee flexion at initial contact, greater abduction angles and external knee abduction moments, higher biceps femoris and semitendinosus muscle pre-activity levels than both the single-planar jump-landings and multi-planar side-jumps (p < .05). Whilst, poor-to-strong spearman rank correlation coefficients inconsistently were found for the biomechanical and neuromuscular ACL injury risk factors explored between the side-cut and the single-planar jump-landings (rs = 0.01–0.78) and multi-planar side-jumps (rs = 0.03–0.88) respectively. ConclusionSingle-planar jump-landings and multi-planar side-jumps should be used with caution to test for non-contact ACL injury risk factors in adolescent female soccer and handball players, because they do not mimic the biomechanical nor neuromuscular demands of the most frequent injury situation.

By failing to prepare, you are preparing your anterior cruciate ligament to fail.

There is strong evidence linking an athlete's movement technique during sidestepping with anterior cruciate ligament (ACL) injury risk. However, it is unclear how these injuriouspostures are influenced by prior movement. We aim to describe preparatory trunk and thigh kinematics at toe-off of the penultimate-step and flight-phase angular momenta, and explore their associations with frontal-plane risk factors during unplanned sidestepping maneuvers. We analyzed kinematic and kinetic data of 33 male Australian Football players performing unplanned sidestepping tasks (103 trials). Linear mixed models tested for reliable associations between ACL injury risk during weight acceptance of the execution-step, with preparatory kinematics and angular momenta of the trunk and thigh during the penultimate-step. Multi-planar flight-phase trunk momenta along with hip abduction angle at penultimate-step toe-off were significantly associated with peak knee valgus moments during the execution-step (R2 =.21, P<.01). Execution-step trunk lateral flexion was significantly predicted by frontal and sagittal-plane preparatory trunk positioning at toe-off of the penultimate-step (R2 =.44, P<.01). Multi-planar flight-phase trunk momenta as well as multi-planar trunk and hip positioning at penultimate-step toe-offwere associated with hip abduction during the execution-step (R2 =.53, P<.01). Preparatory positioning of the trunk and hip, along with flight-phase trunk momentum adjusting this positioning are linked to known ACL injury risk factors. We recommendthat during the penultimate-step athletes maintain an upright trunk, as well as minimize frontal-plane trunk momentum and transverse-plane trunk momentum toward the sidestep direction to reduce risk of ACL injury during unplanned sidesteps.

Increased Radiographic Posterior Tibial Slope Is Associated With Subsequent Injury Following Revision Anterior Cruciate Ligament Reconstruction.

Background:Increased posterior tibial slope has been identified as a possible risk factor for injury to the anterior cruciate ligament (ACL) and has also been shown to be associated with ACL reconstruction graft failure. It is currently unknown whether increased posterior tibial slope is an additional risk factor for further injury in the context of revision ACL reconstruction.Purpose:To determine the relationship between posterior tibial slope and further ACL injury in patients who have already undergone revision ACL reconstruction.Study Design:Cohort study; Level of evidence, 3.Methods:A total of 330 eligible patients who had undergone revision ACL reconstruction between January 2007 and December 2015 were identified from a clinical database. The slope of the medial and lateral tibial plateaus was measured on perioperative lateral radiographs by 2 fellowship-trained orthopaedic surgeons using a digital software application. The number of subsequent ACL injuries (graft rupture or a contralateral injury to the native ACL) was determined at a minimum follow-up of 2 years (range, 2-8 years). Tibial slope measurements were compared between patients who sustained further ACL injury to either knee and those who did not.Results:There were 50 patients who sustained a third ACL injury: 24 of these injuries were to the knee that underwent revision ACL reconstruction, and 26 were to the contralateral knee. Medial and lateral slope values were significantly greater for the third-injury group compared with the no–third injury group (medial, 7.5° vs 6.3° [P = .01]; lateral, 13.6° vs 11.9° [P = .001]).Conclusion:Increased posterior tibial slope, as measured from lateral knee radiographs, was associated with increased risk of graft rupture and contralateral ACL injury after revision ACL reconstruction. This is consistent with the concept that increased posterior slope, particularly of the lateral tibial plateau, is an important risk factor for recurrent ACL injury.

ACL Size and Notch Width Between ACLR and Healthy Individuals: A Pilot Study.

Given the relatively high risk of contralateral anterior cruciate ligament (ACL) injury in patients with ACL reconstruction (ACLR), there is a need to understand intrinsic risk factors that may contribute to contralateral injury. The ACLR group would have smaller ACL volume and a narrower femoral notch width than healthy individuals after accounting for relevant anthropometrics. Cross-sectional study. Level 3. Magnetic resonance imaging data of the left knee were obtained from uninjured (N = 11) and unilateral ACL-reconstructed (N = 10) active, female, collegiate-level recreational athletes. ACL volume was obtained from T2-weighted images. Femoral notch width and notch width index were measured from T1-weighted images. Independent-samples t tests examined differences in all measures between healthy and ACLR participants. The ACLR group had a smaller notch width index (0.22 ± 0.02 vs 0.25 ± 0.01; P = 0.004; effect size, 1.41) and ACL volume (25.6 ± 4.0 vs 32.6 ± 8.2 mm3/(kg·m)-1; P = 0.025; effect size, 1.08) after normalizing by body size. Only after normalizing for relevant anthropometrics, the contralateral ACLR limb had smaller ACL size and narrower relative femoral notch size than healthy individuals. These findings suggest that risk factor studies of ACL size and femoral notch size should account for relevant body size when determining their association with contralateral ACL injury. The present study shows that the method of the identified intrinsic risk factors for contralateral ACL injury could be used in future clinical screening settings.

THE USE OF MICROSOFT KINECT ™ FOR ASSESSING READINESS OF RETURN TO SPORT AND INJURY RISK EXERCISES: A VALIDATION STUDY

Assessing readiness of return to sport after procedures such as anterior cruciate ligament (ACL) reconstruction is a complex process, complicated by the pressures that athletes face in returning to sport as quickly as possible. Advances in motion analysis have been able to demonstrate movements that are risk factors for initial ACL injury and subsequent reinjury after reconstruction. An inexpensive, objective measure is needed to determine when athletes are ready to return to sport after ACL reconstruction. The aim of this study was to compare the use of a single camera, markerless motion capture technology to 3D motion capture during lower extremity movements that pose as risk factors for ACL injury. Cross Sectional Study. This study assessed the validity of the Microsoft Kinect™ against an established 3-dimensional motion analysis system in 20 healthy subjects. Knee kinematics were assessed during impact activity in the coronal and sagittal plane specifically evaluating peak knee valgus and peak knee flexion during single leg hop and jump from box exercises. Intraclass correlation coefficients and 95% limits of agreement (LoA) were determined for each kinematic variable. For the single leg hop, the mean absolute difference in the sagittal plane was 10.4 ° (95% LoA [-11.7 °, 26.8 °]), and in the frontal plane was 5.31 ° (95% LoA [-8 °, 13.9 °]). Similarly, for the jump from box landing on one leg, there was a difference of 7.96 ° (95% LoA [-17.7 °, 21.3 °]) and 4.69 ° (95% LoA [-6.3 °, 12.6 °]) respectively. For the jump from box, two-foot land, turn and pivot, the mean absolute difference between the systems was 7.39 ° (95% LoA [-17.8 °, 19.7 °]) in the sagittal and 4.22 ° (95% LoA [-5.9 °, 11.6 °]) in the frontal plane respectively. Intraclass correlation coefficients for each activity ranged from 0.553 to 0.759. The results from the Microsoft Kinect™ were found to be in poor agreement with those from a standard motion capture system. Measuring complex lower extremity movements with the Microsoft Kinect™ does not provide adequate enough information to use as an assessment tool for injury risk and return to sport timing. Level III.