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OBJECTIVE: Athletes who return to sport after anterior cruciate ligament reconstruction (ACLR) demonstrate persistent biomechanical and neuromuscular deficits of the knee. There is limited evidence on what effect a neuromuscular training (NMT) program has on knee biomechanics in a cohort of athletes with ACLR. Therefore, the primary aim of this study was to quantify the effect of an NMT program on knee biomechanics in a cohort of ACLR athletes. Second, the post-training knee biomechanics were compared between the cohort of ACLR and control athletes. DESIGN: Cohort study. SETTING: Controlled laboratory setting. PARTICIPANTS: Eighteen athletes with ACLR and 10 control athletes. INTERVENTIONS: Neuromuscular training. MAIN OUTCOME MEASURES: Knee kinematics and kinetics during a double-limb jump-landing task. RESULTS: There were no significant interactions (P > 0.05) observed for the athletes with ACLR. However, there was a significant main effect of biomechanics testing session (P < 0.05) for knee flexion angle and moments; athletes with ACLR demonstrated greater knee flexion angle and lower knee flexion moment during the post-training biomechanics testing session. Post-training comparison between the ACLR and control athletes demonstrated no significant interactions (P > 0.05) between the groups. There was a significant main effect of group (P < 0.05) for knee frontal angle, as athletes with ACLR landed with greater knee adduction than the control athletes. CONCLUSIONS: Significant improvements in knee sagittal plane biomechanical measures were observed after the NMT program by the athletes with ACLR. In addition, post-training comparison of the ACLR and control groups demonstrates comparable knee biomechanics.
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Lesiones del Ligamento Cruzado Anterior/fisiopatología , Lesiones del Ligamento Cruzado Anterior/cirugía , Reconstrucción del Ligamento Cruzado Anterior/rehabilitación , Terapia por Ejercicio/métodos , Rodilla/fisiopatología , Adolescente , Fenómenos Biomecánicos , Prueba de Esfuerzo , Humanos , Movimiento , Volver al Deporte , Adulto JovenRESUMEN
OBJECTIVE: Faulty neuromuscular and biomechanical deficits of the knee are nearly ubiquitous in athletes after anterior cruciate ligament (ACL) reconstruction (ACLR). Knee biomechanical deficits are directly associated with an increased risk of second ACL injury, which typically occurs during a sports-related movement on a single limb. To date, the biomechanical effects of a neuromuscular training (NMT) program on knee biomechanics during a single-leg landing task have not been investigated. DESIGN: Prospective Cohort Study. SETTING: Controlled laboratory setting. PARTICIPANTS: Eighteen ACLR and 10 control athletes. INTERVENTIONS: Neuromuscular training. MAIN OUTCOME MEASURES: Knee kinematics and kinetics. RESULTS: There were no significant interactions of session and limb (P > 0.05) for the athletes with ACLR after training. However, there were several significant main effects of session (P < 0.05) for knee kinematics and kinetics during the single-leg landing task. After training, the athletes with ACLR landed with greater knee flexion angles, decreased knee abduction angles, increased knee flexion range of motion, and decreased knee excursion. Also, the ACLR athletes landed with lower knee flexion moments, greater knee adduction moments, and lower peak vertical ground reaction force. Post-training comparison of the ACLR and control cohorts found no significant interactions of group and limb (P > 0.05) and only a significant main effect of group (P < 0.05) for frontal plane knee angle at initial contact. The athletes with ACLR landed with greater knee adduction angles than the control group. CONCLUSIONS: Deficits in knee biomechanics that are associated with an increased risk of ACL injury are attenuated after completion of this NMT program.
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Lesiones del Ligamento Cruzado Anterior , Ligamento Cruzado Anterior , Atletas , Fenómenos Biomecánicos , Humanos , Articulación de la Rodilla , Pierna , Estudios ProspectivosRESUMEN
CONTEXT: Due to the limitations of single-center studies in achieving appropriate sampling with relatively rare disorders, multicenter collaborations have been proposed to achieve desired sampling levels. However, documented reliability of biomechanical data is necessary for multicenter injury-prevention studies and is currently unavailable. OBJECTIVE: To measure the reliability of 3-dimensional (3D) biomechanical waveforms from kinetic and kinematic variables during a single-leg landing (SLL) performed at 3 separate testing facilities. DESIGN: Multicenter reliability study. SETTING: 3 laboratories. PATIENTS: 25 female junior varsity and varsity high school volleyball players who visited each facility over a 1-mo period. INTERVENTION: Subjects were instrumented with 43 reflective markers to record 3D motion as they performed SLLs. During the SLL the athlete balanced on 1 leg, dropped down off of a 31-cm-high box, and landed on the same leg. Kinematic and kinetic data from both legs were processed from 2 trials across the 3 laboratories. MAIN OUTCOME MEASURES: Coefficients of multiple correlations (CMC) were used to statistically compare each joint angle and moment waveform for the first 500 ms of landing. RESULTS: Average CMC for lower-extremity sagittal-plane motion was excellent between laboratories (hip .98, knee .95, ankle .99). Average CMC for lower-extremity frontal-plane motion was also excellent between laboratories (hip .98, knee .80, ankle .93). Kinetic waveforms were repeatable in each plane of rotation (3-center mean CMC ≥.71), while knee sagittal-plane moments were the most consistent measure across sites (3-center mean CMC ≥.94). CONCLUSIONS: CMC waveform comparisons were similar relative to the joint measured to previously published reports of between-sessions reliability of sagittal- and frontal-plane biomechanics performed at a single institution. Continued research is needed to further standardize technology and methods to help ensure that highly reliable results can be achieved with multicenter biomechanical screening models.
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Lesiones del Ligamento Cruzado Anterior , Imagenología Tridimensional , Traumatismos de la Rodilla/prevención & control , Fenómenos Biomecánicos , Femenino , Humanos , Reproducibilidad de los Resultados , Medición de Riesgo/métodosRESUMEN
Multiple computational models have been developed to study knee biomechanics. However, the majority of these models are mainly validated against a limited range of loading conditions and/or do not include sufficient details of the critical anatomical structures within the joint. Due to the multifactorial dynamic nature of knee injuries, anatomic finite element (FE) models validated against multiple factors under a broad range of loading conditions are necessary. This study presents a validated FE model of the lower extremity with an anatomically accurate representation of the knee joint. The model was validated against tibiofemoral kinematics, ligaments strain/force, and articular cartilage pressure data measured directly from static, quasi-static, and dynamic cadaveric experiments. Strong correlations were observed between model predictions and experimental data (r > 0.8 and p < 0.0005 for all comparisons). FE predictions showed low deviations (root-mean-square (RMS) error) from average experimental data under all modes of static and quasi-static loading, falling within 2.5 deg of tibiofemoral rotation, 1% of anterior cruciate ligament (ACL) and medial collateral ligament (MCL) strains, 17 N of ACL load, and 1 mm of tibiofemoral center of pressure. Similarly, the FE model was able to accurately predict tibiofemoral kinematics and ACL and MCL strains during simulated bipedal landings (dynamic loading). In addition to minimal deviation from direct cadaveric measurements, all model predictions fell within 95% confidence intervals of the average experimental data. Agreement between model predictions and experimental data demonstrates the ability of the developed model to predict the kinematics of the human knee joint as well as the complex, nonuniform stress and strain fields that occur in biological soft tissue. Such a model will facilitate the in-depth understanding of a multitude of potential knee injury mechanisms with special emphasis on ACL injury.
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Lesiones del Ligamento Cruzado Anterior , Simulación por Computador , Análisis de Elementos Finitos , Traumatismos de la Rodilla/fisiopatología , Rodilla/patología , Rodilla/fisiopatología , Modelos Anatómicos , Fenómenos Biomecánicos , Humanos , Rango del Movimiento Articular , Análisis de Regresión , Rotación , Estrés Fisiológico , Soporte de PesoRESUMEN
Allograft and bioabsorbable screw use in anterior cruciate ligament (ACL) revision surgery is common. However, both allograft and bioabsorbable screws have been associated with immunologic reactions that lead to tunnel enlargement. Long-term studies examining tibial tunnel enlargement in this population are currently not available. We report a case of severe tibial and femoral tunnel enlargement 6.5 years after ACL revision surgery with anterior tibialis and semitendinosus allograft and bioabsorbable screw fixation. Longitudinal knee arthrometer data, knee examination with the patient under anesthesia, and arthroscopic inspection of the graft showed minimal effects of severe tunnel enlargement on anterior knee laxity and graft integrity. To our knowledge, this is the first case report of a longitudinal assessment of anterior knee laxity associated with severe tunnel enlargement. Surgeons should be aware of this condition and the clinical consequences that may accompany bone tunnel enlargement after ACL surgery.
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Reconstrucción del Ligamento Cruzado Anterior , Inestabilidad de la Articulación/diagnóstico , Inestabilidad de la Articulación/etiología , Complicaciones Posoperatorias/diagnóstico , Implantes Absorbibles , Adulto , Tornillos Óseos , Femenino , Humanos , Reoperación , Tendones/trasplante , Trasplante HomólogoRESUMEN
BACKGROUND: Neuromuscular training (NMT) has been shown to attenuate high-risk biomechanics in uninjured athletes. At the time that athletes return to sport after anterior cruciate ligament (ACL) reconstruction (ACLR), they demonstrate hip biomechanical deficits associated with injury to the reconstructed knee versus the uninjured contralateral knee. PURPOSE: The primary purpose of the study was to examine whether an NMT program can improve single-leg drop (SLD) landing hip biomechanics for athletes after ACLR. Secondarily, we compared the posttraining SLD hip biomechanics of athletes after ACLR with a control group of athletes who also completed the NMT program. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 18 ACLR and 10 uninjured athletes were recruited and completed a 12-session NMT program. A knee-specific questionnaire and biomechanics of an SLD task was evaluated for each athlete before and after NMT. Paired t tests were used to compare pre- and posttraining International Knee Documentation Committee (IKDC) scores. Repeated-measures analysis of variance (ANOVA) was performed to assess the main effects and interactions of testing session × limb for the ACLR athletes. A 2-way ANOVA was conducted to quantify the interactions and main effects of group × limb. RESULTS: There was a significant increase (P = .03) in IKDC scores from pre- to posttraining. For the ACLR athletes, there was a significant session × limb interaction for hip external rotation moment (P = .02) and hip abduction angle (P = .013). Despite increases in hip external rotation moment, no significant changes from pre- to posttraining were observed for the involved limbs. No significant changes were observed for hip abduction angle of the involved limbs between training sessions. Significant main effects of session (P < .05) revealed that athletes landed with greater hip excursion, lower hip flexion moment, and lower ground-reaction force after training. The posttraining comparison between the ACLR and control groups found no significant group × limb interactions for any of the hip kinematic or kinetic variables. A significant main effect of group (P < .05) revealed that the ACLR athletes landed with greater hip flexion angle and hip external rotation moment. CONCLUSION: ACLR athletes demonstrated an improvement in SLD hip biomechanics and neuromuscular control after participating in an NMT program. CLINICAL RELEVANCE: This evidence indicates a potential role for NMT to improve hip biomechanics during an SLD task so as to reduce ACL injury risk.
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BACKGROUND: Anterior cruciate ligament tears have a negative psychological impact on athletes. Currently, it is not clear if psychological readiness to return to sport has an impact on an athlete's landing biomechanics. Thus the purpose of the study is to investigate whether there is an association of psychological readiness to return to sport and single-leg landing biomechanics. METHODS: Athletes with an anterior cruciate ligament reconstruction (nâ¯=â¯18) completed the Anterior Cruciate Ligament-Return to Sport after Injury scale to measure psychological readiness to return to sport, knee strength testing, and a single-leg landing task. A multivariate linear regression model was built for the involved and uninvolved limb based on sagittal and frontal plane knee and hip range of motion. Significance was set at pâ¯<â¯0.05. FINDINGS: Knee extensor/flexor strength testing showed significant differences (pâ¯<â¯0.05) between involved and uninvolved limbs. Nearly 40% of the variance in psychological readiness scores (pâ¯=â¯0.025) can be accounted for by the involved limb's frontal plane hip and knee range of motion. Knee frontal plane range of motion was the only significant factor, and the standardized coefficients indicate that greater knee frontal plane range of motion and lower hip frontal plane range of motion were associated with higher psychological readiness. No other associations were found between psychological readiness and sagittal or frontal plane sing-leg biomechanics of the involved or uninvolved limbs. INTERPRETATION: Greater psychological readiness to return to sport is associated with the involved limb's frontal plane knee and hip range of motion during a single-leg landing biomechanics.
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Lesiones del Ligamento Cruzado Anterior/cirugía , Reconstrucción del Ligamento Cruzado Anterior/psicología , Articulación de la Rodilla/cirugía , Rodilla/cirugía , Volver al Deporte/psicología , Adolescente , Adulto , Ligamento Cruzado Anterior/cirugía , Lesiones del Ligamento Cruzado Anterior/psicología , Atletas , Fenómenos Biomecánicos , Femenino , Humanos , Masculino , Análisis Multivariante , Rango del Movimiento Articular , Índice de Severidad de la Enfermedad , Deportes , Adulto JovenRESUMEN
BACKGROUND: The efficacy of a neuromuscular training (NMT) program to ameliorate known hip biomechanical risk factors for athletes with anterior cruciate ligament reconstruction (ACLR) is currently unknown. Purpose/Hypothesis: The purpose was to quantify the effects of an NMT program on hip biomechanics among athletes with ACLR and to compare posttraining hip biomechanics with a control group. The hypotheses were that known hip biomechanical risk factors of anterior cruciate ligament (ACL) injury would be significantly reduced among athletes with ACLR after the NMT program and that posttraining hip biomechanics between the ACLR and control cohorts would not differ. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty-eight athletes (n = 18, ACLR; n = 10, uninjured) completed a 12-session NMT program. Biomechanical evaluation of a jump-landing task was done before and after completion of the program. Repeated measures analysis of variance was performed to understand the effect of NMT within the ACLR cohort. Two-way analysis of variance was used to compare both groups. Post hoc testing was done for significant interactions. Hip biomechanical variables at initial contact are reported. RESULTS: The athletes with ACLR who completed the NMT program had a significant session × limb interaction ( P = .01) for hip external rotation moment and a significant main effect of session for hip flexion angle ( P = .049) and moment ( P < .001). There was a significant change for the involved ( P = .04; 528% increase) and uninvolved ( P = .04; 57% decrease) limbs from pre- to posttraining for hip rotation moment. The ACLR cohort had an increase in hip flexion angle (14% change) and a decrease in hip flexion moment (65% change) from pre- to posttraining. Posttraining comparison for these same hip biomechanical variables of interest revealed no significant interactions ( P > .05) between the ACLR and control cohorts. There was a significant main effect of group ( P = .02) for hip flexion angle, as the ACLR cohort demonstrated greater hip flexion angle than that of the control group. CONCLUSION: For athletes with ACLR, hip biomechanical measures of ACL injury risk show significant improvements after completion of an NMT program. CLINICAL RELEVANCE: Athletes with ACLR who are participating in an NMT program may ameliorate known hip biomechanical risk factors for an ACL injury.
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Lesiones del Ligamento Cruzado Anterior/fisiopatología , Lesiones del Ligamento Cruzado Anterior/cirugía , Reconstrucción del Ligamento Cruzado Anterior , Traumatismos en Atletas/fisiopatología , Traumatismos en Atletas/cirugía , Terapia por Ejercicio/métodos , Cadera/fisiopatología , Adulto , Fenómenos Biomecánicos , Estudios de Cohortes , Femenino , Humanos , Masculino , Rango del Movimiento Articular , Rotación , Adulto JovenRESUMEN
Femoral nerve block (FNB) has been proposed for pain control following anterior cruciate ligament (ACL) reconstruction. Although numerous studies have assessed the efficacy of FNBs, there has been little to no research into the effect of such blocks on postoperative strength and patient-reported outcomes. We hypothesized that performance of an FNB would result in decreased quadriceps strength and poorer patient-reported outcome scores within the first 6 months following ACL reconstruction. A total of 30 patients scheduled to undergo hamstring autograft ACL reconstruction following an acute ACL injury were randomized to a single-shot FNB group or a control group. Preoperatively, patients completed a Knee Injury and Osteoarthritis Outcome Score (KOOS) and isokinetic quadriceps strength testing at 60 degrees/second. At 6 weeks postoperative, 29 of 30 patients completed a KOOS and isometric quadriceps strength testing at 90 degrees. At 6 months postoperative, 23 of 30 patients completed a KOOS and isokinetic strength testing. Quadriceps femoris strength limb symmetry indices (QF-LSI) were calculated at all time points. Repeated measures analysis of variance (ANOVA) models were then utilized to model the effect of FNB and time on QF-LSI as well as KOOS subscales for activities of daily living, pain, and symptoms. QF-LSI and all KOOS subscales demonstrated improvement with time following ACL reconstruction. Repeated measures ANOVA demonstrated that patients who underwent FNB had a mean QF-LSI that was 13.4% lower than the control group (p = 0.005) and poorer KOOS symptoms subscale scores (10.4 point difference, p = 0.032) at 6 weeks postoperative compared with controls. At 6 months postoperative, no differences were noted in QF-LSI or any of the KOOS subscales based on block status. FNB resulted in decreased strength and poorer KOOS symptom subscale score at 6 weeks following ACL reconstruction compared with controls. These differences resolved by 6 months postoperative. The long-term effect of delayed quadriceps recovery on movement patterns and functional outcome remains unknown and requires further study. The study is a randomized controlled trial with level of evidence 1.
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Reconstrucción del Ligamento Cruzado Anterior , Nervio Femoral , Bloqueo Nervioso , Dolor Postoperatorio/prevención & control , Adulto , Femenino , Humanos , Masculino , Fuerza Muscular , Medición de Resultados Informados por el Paciente , Músculo Cuádriceps , Adulto JovenRESUMEN
BACKGROUND: Correction of neuromuscular impairments after anterior cruciate ligament injury is vital to successful return to sport. Frontal plane knee control during landing is a common measure of lower-extremity neuromuscular control and asymmetries in neuromuscular control of the knee can predispose injured athletes to additional injury and associated morbidities. Therefore, this study investigated the effects of anterior cruciate ligament injury on knee biomechanics during landing. METHODS: Two-dimensional frontal plane video of single leg drop, cross over drop, and drop vertical jump dynamic movement trials was analyzed for twenty injured and reconstructed athletes. The position of the knee joint center was tracked in ImageJ software for 500 milliseconds after landing to calculate medio-lateral knee motion velocities and determine normal fluency, the number of times per second knee velocity changed direction. The inverse of this calculation, analytical fluency, was used to associate larger numerical values with fluent movement. FINDINGS: Analytical fluency was decreased in involved limbs for single leg drop trials (P=0.0018). Importantly, analytical fluency for single leg drop differed compared to cross over drop trials for involved (P<0.001), but not uninvolved limbs (P=0.5029). For involved limbs, analytical fluency values exhibited a stepwise trend in relative magnitudes. INTERPRETATION: Decreased analytical fluency in involved limbs is consistent with previous studies. Fluency asymmetries observed during single leg drop tasks may be indicative of abhorrent landing strategies in the involved limb. Analytical fluency differences in unilateral tasks for injured limbs may represent neuromuscular impairment as a result of injury.
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Lesiones del Ligamento Cruzado Anterior , Traumatismos en Atletas/fisiopatología , Rodilla/fisiopatología , Ligamento Cruzado Anterior/cirugía , Reconstrucción del Ligamento Cruzado Anterior , Traumatismos en Atletas/cirugía , Fenómenos Biomecánicos , Ejercicio Físico/fisiología , Femenino , Humanos , Masculino , Movimiento , Análisis y Desempeño de Tareas , Adulto JovenRESUMEN
BACKGROUND: Despite basic characterization of the loading factors that strain the anterior cruciate ligament (ACL), the interrelationship(s) and additive nature of these loads that occur during noncontact ACL injuries remain incompletely characterized. HYPOTHESIS: In the presence of an impulsive axial compression, simulating vertical ground-reaction force during landing (1) both knee abduction and internal tibial rotation moments would result in increased peak ACL strain, and (2) a combined multiplanar loading condition, including both knee abduction and internal tibial rotation moments, would increase the peak ACL strain to levels greater than those under uniplanar loading modes alone. STUDY DESIGN: Controlled laboratory study. METHODS: A cadaveric model of landing was used to simulate dynamic landings during a jump in 17 cadaveric lower extremities (age, 45 ± 7 years; 9 female and 8 male). Peak ACL strain was measured in situ and characterized under impulsive axial compression and simulated muscle forces (baseline) followed by addition of anterior tibial shear, knee abduction, and internal tibial rotation loads in both uni- and multiplanar modes, simulating a broad range of landing conditions. The associations between knee rotational kinematics and peak ACL strain levels were further investigated to determine the potential noncontact injury mechanism. RESULTS: Externally applied loads, under both uni- and multiplanar conditions, resulted in consistent increases in peak ACL strain compared with the baseline during simulated landings (by up to 3.5-fold; P ≤ .032). Combined multiplanar loading resulted in the greatest increases in peak ACL strain (P < .001). Degrees of knee abduction rotation (R(2) = 0.45; ß = 0.42) and internal tibial rotation (R(2) = 0.32; ß = 0.23) were both significantly correlated with peak ACL strain (P < .001). However, changes in knee abduction rotation had a significantly greater effect size on peak ACL strain levels than did internal tibial rotation (by ~2-fold; P < .001). CONCLUSION: In the presence of impulsive axial compression, the combination of anterior tibial shear force, knee abduction, and internal tibial rotation moments significantly increases ACL strain, which could result in ACL failure. These findings support multiplanar knee valgus collapse as one the primary mechanisms of noncontact ACL injuries during landing. CLINICAL RELEVANCE: Intervention programs that address multiple planes of loading may decrease the risk of ACL injury and the devastating consequences of posttraumatic knee osteoarthritis.
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Lesiones del Ligamento Cruzado Anterior/fisiopatología , Ligamento Cruzado Anterior/fisiopatología , Ejercicio Pliométrico , Adulto , Ligamento Cruzado Anterior/fisiología , Lesiones del Ligamento Cruzado Anterior/complicaciones , Fenómenos Biomecánicos , Femenino , Humanos , Rodilla/fisiopatología , Masculino , Persona de Mediana Edad , Osteoartritis de la Rodilla/etiología , Presión , Rotación , Tibia/fisiologíaRESUMEN
Anterior superior iliac spine (ASIS) marker occlusion commonly occurs during three-dimensional (3-D) motion capture of dynamic tasks with deep hip flexion. The purpose of this study was to validate a universal technique to correct ASIS occlusion. 420 ms of bilateral ASIS marker occlusion was simulated in fourteen drop vertical jump (DVJ) trials (n=14). Kinematic and kinetic hip data calculated for pelvic segments based on iliac crest (IC) marker and virtual ASIS (produced by our algorithm and a commercial virtual join) trajectories were compared to true ASIS marker tracking data. Root mean squared errors (RMSEs; mean±standard deviation) and intra-class correlations (ICCs) between pelvic tracking based on virtual ASIS trajectories filled by our algorithm and true ASIS position were 2.3±0.9° (ICC=0.982) flexion/extension, 0.8±0.2° (ICC=0.954) abduction/adduction for hip angles, and 0.40±0.17 N m (ICC=1.000) and 1.05±0.36 N m (ICC=0.998) for sagittal and frontal plane moments. RMSEs for IC pelvic tracking were 6.9±1.8° (ICC=0.888) flexion/extension, 0.8±0.3° (ICC=0.949) abduction/adduction for hip angles, and 0.31±0.13 N m (ICC=1.00) and 1.48±0.69 N m (ICC=0.996) for sagittal and frontal plane moments. Finally, the commercially-available virtual join demonstrated RMSEs of 4.4±1.5° (ICC=0.945) flexion/extension, 0.7±0.2° (ICC=0.972) abduction/adduction for hip angles, and 0.97±0.62 N m (ICC=1.000) and 1.49±0.67 N m (ICC=0.996) for sagittal and frontal plane moments. The presented algorithm exceeded the a priori ICC cutoff of 0.95 for excellent validity and is an acceptable tracking alternative. While ICCs for the commercially available virtual join did not exhibit excellent correlation, good validity was observed for all kinematics and kinetics. IC marker pelvic tracking is not a valid alternative.
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Movimiento , Algoritmos , Fenómenos Biomecánicos , Humanos , Ilion/fisiología , Modelos Biológicos , Columna Vertebral/fisiologíaRESUMEN
Despite general agreement on the effects of knee valgus and internal tibial rotation on anterior cruciate ligament (ACL) loading, compelling debate persists on the interrelationship between these rotations and how they contribute to the multi-planar ACL injury mechanism. This study investigates coupling between knee valgus and internal tibial rotation and their effects on ACL strain as a quantifiable measure of injury risk. Nineteen instrumented cadaveric legs were imaged and tested under a range of knee valgus and internal tibial torques. Posterior tibial slope and the medial tibial depth, along with changes in tibiofemoral kinematics and ACL strain, were quantified. Valgus torque significantly increased knee valgus rotation and ACL strain (p<0.020), yet generated minimal coupled internal tibial rotation (p=0.537). Applied internal tibial torque significantly increased internal tibial rotation and ACL strain and generated significant coupled knee valgus rotation (p<0.001 for all comparisons). Similar knee valgus rotations (7.3° vs 7.4°) and ACL strain levels (4.4% vs 4.9%) were observed under 50 Nm of valgus and 20 Nm of internal tibial torques, respectively. Coupled knee valgus rotation under 20 Nm of internal tibial torque was significantly correlated with internal tibial rotation, lateral and medial tibial slopes, and medial tibial depth (R(2)>0.30; p<0.020). These findings demonstrate uni-directional coupling between knee valgus and internal tibial rotation in a cadaveric model. Although both knee valgus and internal tibial torques contribute to increased ACL strain, knee valgus rotation has the ultimate impact on ACL strain regardless of loading mode.
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Lesiones del Ligamento Cruzado Anterior , Traumatismos de la Rodilla/fisiopatología , Articulación de la Rodilla/fisiopatología , Adulto , Ligamento Cruzado Anterior/fisiopatología , Fenómenos Biomecánicos , Femenino , Humanos , Pierna/fisiología , Masculino , Persona de Mediana Edad , Rotación , Tibia/fisiología , TorqueRESUMEN
BACKGROUND: Anterior cruciate ligament (ACL) injuries are physically and financially devastating but affect a relatively small percentage of the population. Prospective identification of risk factors for ACL injury necessitates a large sample size; therefore, study of this injury would benefit from a multicenter approach. PURPOSE: To determine the reliability of kinematic and kinetic measures of a single-leg cross drop task across 3 institutions. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty-five female high school volleyball players participated in this study. Three-dimensional motion data of each participant performing the single-leg cross drop were collected at 3 institutions over a period of 4 weeks. Coefficients of multiple correlation were calculated to assess the reliability of kinematic and kinetic measures during the landing phase of the movement. RESULTS: Between-centers reliability for kinematic waveforms in the frontal and sagittal planes was good, but moderate in the transverse plane. Between-centers reliability for kinetic waveforms was good in the sagittal, frontal, and transverse planes. CONCLUSION: Based on these findings, the single-leg cross drop task has moderate to good reliability of kinematic and kinetic measures across institutions after implementation of a standardized testing protocol. CLINICAL RELEVANCE: Multicenter collaborations can increase study numbers and generalize results, which is beneficial for studies of relatively rare phenomena, such as ACL injury. An important step is to determine the reliability of risk assessments across institutions before a multicenter collaboration can be initiated.
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BACKGROUND: Bone bruising is commonly observed on magnetic resonance imaging (MRI) after non-contact anterior cruciate ligament (ACL) injury. OBJECTIVES: The primary objective of this study was to determine if the location and prevalence of tibial and femoral bone bruises after ACL injury can be explained by specific injury mechanism(s). The secondary objective was to determine whether the bone-bruise literature supports sex-specific injury mechanism(s). We hypothesized that most studies would report bone bruising in the lateral femoral condyle (LFC) and on the posterior lateral tibial plateau (LTP). METHODS: MEDLINE, PubMed, and SCOPUS were searched for studies that reported bone bruise prevalence and location in ACL-injured subjects. Sex differences in bone-bruise patterns were assessed. Time from injury to imaging was assessed to account for confounding effects on bone-bruise size and location. RESULTS: Thirty-eight studies met the inclusion/exclusion criteria. Anterior-posterior location of bone bruises within the tibiofemoral compartment was assessed in 11 studies. Only five of these studies reported bone-bruise locations on both the tibia and the femur. The most common bone-bruise combination in all five studies was on the LFC and the posterior LTP. Sex differences were only assessed in three studies, and only one reported significantly greater prevalence of LTP bruising in females. CONCLUSION: Bone-bruise patterns in the current literature support a valgus-driven ACL injury mechanism; however, more studies should report the specific locations of tibial and femoral bone bruises. There is insufficient evidence in the literature to determine whether there are sex-specific bone-bruise patterns in ACL-injured subjects.
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Lesiones del Ligamento Cruzado Anterior , Traumatismos en Atletas/epidemiología , Contusiones/etiología , Fémur/lesiones , Traumatismos de la Rodilla/complicaciones , Tibia/lesiones , Traumatismos en Atletas/complicaciones , Traumatismos en Atletas/etiología , Contusiones/epidemiología , Femenino , Humanos , Traumatismos de la Rodilla/epidemiología , Imagen por Resonancia Magnética , Masculino , PrevalenciaRESUMEN
Finite element (FE) analysis has become an increasingly popular technique in the study of human joint biomechanics, as it allows for detailed analysis of the joint/tissue behavior under complex, clinically relevant loading conditions. A wide variety of modeling techniques have been utilized to model knee joint ligaments. However, the effect of a selected constitutive model to simulate the ligaments on knee kinematics remains unclear. The purpose of the current study was to determine the effect of two most common techniques utilized to model knee ligaments on joint kinematics under functional loading conditions. We hypothesized that anatomic representations of the knee ligaments with anisotropic hyperelastic properties will result in more realistic kinematics. A previously developed, extensively validated anatomic FE model of the knee developed from a healthy, young female athlete was used. FE models with 3D anatomic and simplified uniaxial representations of main knee ligaments were used to simulate four functional loading conditions. Model predictions of tibiofemoral joint kinematics were compared to experimental measures. Results demonstrated the ability of the anatomic representation of the knee ligaments (3D geometry along with anisotropic hyperelastic material) in more physiologic prediction of the human knee motion with strong correlation (r ≥ 0.9 for all comparisons) and minimum deviation (0.9º ≤ RMSE ≤ 2.29°) from experimental findings. In contrast, non-physiologic uniaxial elastic representation of the ligaments resulted in lower correlations (r ≤ 0.6 for all comparisons) and substantially higher deviation (2.6° ≤ RMSE ≤ 4.2°) from experimental results. Findings of the current study support our hypothesis and highlight the critical role of soft tissue modeling technique on the resultant FE predicted joint kinematics.
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BACKGROUND: Previous studies have indicated that higher knee joint laxity may be indicative of an increased risk of anterior cruciate ligament (ACL) injuries. Despite the frequent clinical use of knee arthrometry in the evaluation of knee laxity, little data exist to correlate instrumented laxity measures and ACL strain during dynamic high-risk activities. Purpose/ HYPOTHESES: The purpose of this study was to evaluate the relationships between ACL strain and anterior knee laxity measurements using arthrometry during both a drawer test and simulated bipedal landing (as an identified high-risk injurious task). We hypothesized that a high correlation exists between dynamic ACL strain and passive arthrometry displacement. The secondary hypothesis was that anterior knee laxity quantified by knee arthrometry is a valid predictor of injury risk such that specimens with greater anterior knee laxity would demonstrate increased levels of peak ACL strain during landing. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty cadaveric lower limbs (mean age, 46 ± 6 years; 10 female and 10 male) were tested using a CompuKT knee arthrometer to measure knee joint laxity. Each specimen was tested under 4 continuous cycles of anterior-posterior shear force (±134 N) applied to the tibial tubercle. To quantify ACL strain, a differential variable reluctance transducer (DVRT) was arthroscopically placed on the ACL (anteromedial bundle), and specimens were retested. Subsequently, bipedal landing from 30 cm was simulated in a subset of 14 specimens (mean age, 45 ± 6 years; 6 female and 8 male) using a novel custom-designed drop stand. Changes in joint laxity and ACL strain under applied anterior shear force were statistically analyzed using paired sample t tests and analysis of variance. Multiple linear regression analyses were conducted to determine the relationship between anterior shear force, anterior tibial translation, and ACL strain. RESULTS: During simulated drawer tests, 134 N of applied anterior shear load produced a mean peak anterior tibial translation of 3.1 ± 1.1 mm and a mean peak ACL strain of 4.9% ± 4.3%. Anterior shear load was a significant determinant of anterior tibial translation (P < .0005) and peak ACL strain (P = .04). A significant correlation (r = 0.52, P < .0005) was observed between anterior tibial translation and ACL strain. Cadaveric simulations of landing produced a mean axial impact load of 4070 ± 732 N. Simulated landing significantly increased the mean peak anterior tibial translation to 10.4 ± 3.5 mm and the mean peak ACL strain to 6.8% ± 2.8% (P < .0005) compared with the prelanding condition. Significant correlations were observed between peak ACL strain during simulated landing and anterior tibial translation quantified by knee arthrometry. CONCLUSION: Our first hypothesis is supported by a significant correlation between arthrometry displacement collected during laxity tests and concurrent ACL strain calculated from DVRT measurements. Experimental findings also support our second hypothesis that instrumented measures of anterior knee laxity predict peak ACL strain during landing, while specimens with greater knee laxity demonstrated higher levels of peak ACL strain during landing. CLINICAL RELEVANCE: The current findings highlight the importance of instrumented anterior knee laxity assessments as a potential indicator of the risk of ACL injuries in addition to its clinical utility in the evaluation of ACL integrity.
Asunto(s)
Lesiones del Ligamento Cruzado Anterior , Ligamento Cruzado Anterior/fisiopatología , Inestabilidad de la Articulación/diagnóstico , Inestabilidad de la Articulación/fisiopatología , Articulación de la Rodilla/fisiopatología , Artroscopía , Fenómenos Biomecánicos , Cadáver , Femenino , Humanos , Masculino , Persona de Mediana Edad , Examen Físico , Valor Predictivo de las PruebasRESUMEN
BACKGROUND: Strong biomechanical and epidemiological evidence associates knee valgus collapse with isolated, noncontact anterior cruciate ligament (ACL) injuries. However, a concomitant injury to the medial collateral ligament (MCL) would be expected under valgus collapse, based on the MCL's anatomic orientation and biomechanical role in knee stability. Purpose/ HYPOTHESIS: The purpose of this study was to investigate the relative ACL to MCL strain patterns during physiological simulations of a wide range of high-risk dynamic landing scenarios. We hypothesized that both knee abduction and internal tibial rotation moments would generate a disproportionate increase in the ACL strain relative to the MCL strain. However, the physiological range of knee abduction and internal tibial rotation moments that produce ACL injuries are not of sufficient magnitude to compromise the MCL's integrity consistently. STUDY DESIGN: Controlled laboratory study. METHODS: A novel in sim approach was used to test our hypothesis. Seventeen cadaveric lower extremities (mean age, 45 ± 7 years; 9 female and 8 male) were tested to simulate a broad range of landings after a jump under anterior tibial shear force, knee abduction, and internal tibial rotation at 25° of knee flexion. The ACL and MCL strains were quantified using differential variable reluctance transducers. An extensively validated, detailed finite element model of the lower extremity was used to help better interpret experimental findings. RESULTS: Anterior cruciate ligament failure occurred in 15 of 17 specimens (88%). Increased anterior tibial shear force and knee abduction and internal tibial rotation moments resulted in significantly higher ACL:MCL strain ratios (P < .05). Under all modes of single-planar and multiplanar loading, the ACL:MCL strain ratio remained greater than 1.7, while the relative ACL strain was significantly higher than the relative MCL strain (P < .01). Relative change in the ACL strain was demonstrated to be significantly greater under combined multiplanar loading compared with anterior tibial shear force (P = .016), knee abduction (P = .018), and internal tibial rotation (P < .0005) moments alone. CONCLUSION: While both the ACL and the MCL resist knee valgus during landing, physiological magnitudes of the applied loads leading to high ACL strain levels and injuries were not sufficient to compromise the MCL's integrity. CLINICAL RELEVANCE: A better understanding of injury mechanisms may provide insight that improves current risk screening and injury prevention strategies. Current findings support multiplanar knee valgus collapse as a primary factor contributing to a noncontact ACL injury.
Asunto(s)
Ligamento Cruzado Anterior/fisiología , Ligamento Colateral Medial de la Rodilla/fisiología , Lesiones del Ligamento Cruzado Anterior , Fenómenos Biomecánicos , Cadáver , Femenino , Humanos , Masculino , Ligamento Colateral Medial de la Rodilla/lesiones , Persona de Mediana Edad , Rotación , Estrés MecánicoRESUMEN
BACKGROUND: Challenges in accurate, in vivo quantification of multi-planar knee kinematics and relevant timing sequence during high-risk injurious tasks pose challenges in understanding the relative contributions of joint loads in non-contact injury mechanisms. Biomechanical testing on human cadaveric tissue, if properly designed, offers a practical means to evaluate joint biomechanics and injury mechanisms. This study seeks to investigate the detailed interactions between tibiofemoral joint multi-planar kinematics and anterior cruciate ligament strain in a cadaveric model of landing using a validated physiologic drop-stand apparatus. METHODS: Sixteen instrumented cadaveric legs, mean 45(SD 7) years (8 female and 8 male) were tested. Event timing sequence, change in tibiofemoral kinematics (position, angular velocity and linear acceleration) and change in anterior cruciate ligament strain were quantified. FINDINGS: The proposed cadaveric model demonstrated similar tibiofemoral kinematics/kinetics as reported measurements obtained from in vivo studies. While knee flexion, anterior tibial translation, knee abduction and increased anterior cruciate ligament strain initiated and reached maximum values almost simultaneously, internal tibial rotation initiated and peaked significantly later (P<0.015 for all comparisons). Further, internal tibial rotation reached mean 1.8(SD 2.5)°, almost 63% of its maximum value, at the time that peak anterior cruciate ligament strain occurred, while both anterior tibial translation and knee abduction had already reached their peaks. INTERPRETATION: Together, these findings indicate that although internal tibial rotation contributes to increased anterior cruciate ligament strain, it is secondary to knee abduction and anterior tibial translation in its effect on anterior cruciate ligament strain and potential risk of injury.
Asunto(s)
Lesiones del Ligamento Cruzado Anterior , Ligamento Cruzado Anterior/fisiopatología , Articulación de la Rodilla/fisiología , Adulto , Fenómenos Biomecánicos/fisiología , Biofisica/instrumentación , Cadáver , Femenino , Fémur/fisiología , Humanos , Masculino , Persona de Mediana Edad , Rotación , Tibia/fisiología , Factores de TiempoRESUMEN
PURPOSE/BACKGROUND: Multi-center collaborations provide a powerful alternative to overcome the inherent limitations to single-center investigations. Specifically, multi-center projects can support large-scale prospective, longitudinal studies that investigate relatively uncommon outcomes, such as anterior cruciate ligament injury. This project was conceived to assess within- and between-center reliability of an affordable, clinical nomogram utilizing two-dimensional video methods to screen for risk of knee injury. The authors hypothesized that the two-dimensional screening methods would provide good-to-excellent reliability within and between institutions for assessment of frontal and sagittal plane biomechanics. METHODS: Nineteen female, high school athletes participated. Two-dimensional video kinematics of the lower extremity during a drop vertical jump task were collected on all 19 study participants at each of the three facilities. Within-center and between-center reliability were assessed with intra- and inter-class correlation coefficients. RESULTS: Within-center reliability of the clinical nomogram variables was consistently excellent, but between-center reliability was fair-to-good. Within-center intra-class correlation coefficient for all nomogram variables combined was 0.98, while combined between-center inter-class correlation coefficient was 0.63. CONCLUSIONS: Injury risk screening protocols were reliable within and repeatable between centers. These results demonstrate the feasibility of multi-site biomechanical studies and establish a framework for further dissemination of injury risk screening algorithms. Specifically, multi-center studies may allow for further validation and optimization of two-dimensional video screening tools. LEVEL OF EVIDENCE: 2b.