A Comparison of Knee Abduction Angles Measured by a 3D Anatomic Coordinate System Versus Videographic Analysis: Implications for Anterior Cruciate Ligament Injury

Englander, Zoë A.; Cutcliffe, Hattie C.; Utturkar, Gangadhar M.; Garrett, William E.; Spritzer, Charles E.; DeFrate, Louis E.

doi:10.1177/2325967118819831

Cited by 9 publications

(14 citation statements)

References 35 publications

(89 reference statements)

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“…23 After reproducing the in vivo positions of the bones during the jump (Figure 4), knee flexion angle, patellar tendon orientation, and the length of the ACL and patellar tendon were measured using a standardized anatomic coordinate system ( Figure 5). 20,28,51 The flexion angle was measured about the femoral transepicondylar axis and defined as the angle between the long axis of the femur and the long axis of the tibia. Zero degrees of knee flexion is indicative of a straight knee, and increasingly positive angles are indicative of increasing knee flexion.…”

Section: Methodsmentioning

confidence: 99%

“…4,25 Knee joint kinematics and ligament deformations have been measured in vivo using biplanar radiography integrated with 3-dimensional (3-D) models of the knee joint created from magnetic resonance imaging (MRI). 14,20,23,36,51 These joint models may consist of the femur, tibia, and associated ligament or tendon attachment site footprints. By registering the bone models to the biplanar radiographs, the 3-D positions of the bones at the time of radiographic imaging can be reproduced.…”

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confidence: 99%

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Patellar Tendon Orientation and Strain Are Predictors of ACL Strain In Vivo During a Single-Leg Jump

Englander

Lau

Wittstein

et al. 2021

Orthopaedic Journal of Sports Medicine

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Background: There is little in vivo data that describe the relationships between patellar tendon orientation, patellar tendon strain, and anterior cruciate ligament (ACL) strain during dynamic activities. Quantifying how the quadriceps load the ACL via the patellar tendon is important for understanding ACL injury mechanisms. Hypothesis: We hypothesized that flexion angle, patellar tendon orientation, and patellar tendon strain influence ACL strain during a single-leg jump. Specifically, we hypothesized that patellar tendon and ACL strains would increase concurrently when the knee is positioned near extension during the jump. Study Design: Descriptive laboratory study. Methods: Models of the femur, tibia, ACL, patellar tendon, and quadriceps tendon attachment sites of 8 male participants were generated from magnetic resonance imaging (MRI). High-speed biplanar radiographs during a single-leg jump were obtained. The bone models were registered to the radiographs, thereby reproducing the in vivo positions of the bones, ligament, and tendon attachment sites. Flexion angle, patellar tendon orientation, patellar tendon strain, and ACL strain were measured from the registered models. ACL and patellar tendon strains were approximated by normalizing their length at each knee position to their length at the time of MRI. Two separate bivariate linear regression models were used to assess relationships between flexion angle and patellar tendon orientation and between ACL strain and patellar tendon strain. A multivariate linear regression model was used to assess whether flexion angle and patellar tendon strain were significant predictors of ACL strain during the inflight and landing portions of the jump. Results: Both flexion angle and patellar tendon strain were significant predictors ( P < .05) of ACL strain. These results indicate that elevated ACL and patellar tendon strains were observed concurrently when the knee was positioned near extension. Conclusion: Concurrent increases in patellar tendon and ACL strains indicate that the quadriceps load the ACL via the patellar tendon when the knee is positioned near extension. Clinical Relevance: Increased ACL strain when the knee is positioned near extension before landing may be due to quadriceps contraction. Thus, landing with unanticipated timing on an extended knee may increase vulnerability to ACL injury as a taut ligament is more likely to fail.

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Patellar Tendon Orientation and Strain Are Predictors of ACL Strain In Vivo During a Single-Leg Jump

Englander

Lau

Wittstein

et al. 2021

Orthopaedic Journal of Sports Medicine

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“…After reproducing the in vivo positions of the bones during the full gait cycle (Figure 4), the attachment site to attachment site lengths of the ACL and its bundles, as well as knee flexion angles, were measured from the 3D models of the joint (Englander et al, 2019b;. Flexion angle was defined as the angle between the long axes of the femur and tibia about the femoral transepicondylar axis.…”

Section: Methodsmentioning

confidence: 99%

In vivo attachment site to attachment site length and strain of the ACL and its bundles during the full gait cycle measured by MRI and high-speed biplanar radiography

Englander

Garrett

Spritzer

et al. 2020

Journal of Biomechanics

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The purpose of this study was to measure in vivo attachment site to attachment site lengths and strains of the anterior cruciate ligament (ACL) and its bundles throughout a full cycle of treadmill gait. To obtain these measurements, models of the femur, tibia, and associated ACL attachment sites were created from magnetic resonance (MR) images in 10 healthy subjects. ACL attachment sites were subdivided into anteromedial (AM) and posterolateral (PL) bundles. High-speed biplanar radiographs were obtained as subjects ambulated at 1 m/s. The bone models were registered to the radiographs, thereby reproducing the in vivo positions of the bones and ACL attachment sites throughout gait. The lengths of the ACL and both bundles were estimated as straight line distances between attachment sites for each knee position. Increased attachment to attachment ACL length and strain were observed during midstance (length = 28.5±2.6 mm, strain = 5±4%, mean ± standard deviation), and heel strike (length = 30.5±3.0 mm, strain = 12±5%) when the knee was positioned at low flexion angles. Significant inverse correlations were observed between mean attachment to attachment ACL lengths and flexion (rho=−0.87, p<0.001), as well as both bundle lengths and flexion (rho=−0.86, p<0.001 and rho = −0.82, p<0.001, respectively). AM and PL bundle attachment to attachment lengths were highly correlated throughout treadmill gait (rho = 0.90, p<0.001). These data can provide valuable information to inform design criteria for ACL grafts used in reconstructive surgery, and may be useful in the design of rehabilitation and injury prevention protocols.

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“…After reproduction of the in vivo positions of the bones during the jump (Figure 2), knee flexion angle and the length of the ACL and its bundles were measured through use of a standardized anatomic coordinate system. 17,25,49 Flexion angle was measured as the rotation of the long axis of the femur relative to the long axis of the tibia with the femoral transepicondylar axis as the axis of rotation. Overall ACL length was measured as the centroid to centroid distance between the footprints of the femoral and tibial attachment sites.…”

Section: Methodsmentioning

confidence: 99%

In Vivo Anterior Cruciate Ligament Deformation During a Single-Legged Jump Measured by Magnetic Resonance Imaging and High-Speed Biplanar Radiography

et al. 2019

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Background: The in vivo mechanics of the anterior cruciate ligament (ACL) and its bundles during dynamic activities are not completely understood. An improved understanding of how the ACL stabilizes the knee is likely to aid in the identification and prevention of injurious maneuvers. Purpose/Hypothesis: The purpose was to measure in vivo ACL strain during a single-legged jump through use of magnetic resonance imaging (MRI) and high-speed biplanar radiography. We hypothesized that ACL strain would increase with the knee near extension, and a peak in ACL strain would occur just before landing from the jump, potentially due to quadriceps contraction in anticipation of landing. Study Design: Descriptive laboratory study. Methods: Models of the femur, tibia, and ACL attachment sites of 8 male participants were generated from MRI scans through use of solid modeling. High-speed biplanar radiographs were obtained from these participants as they performed a single-legged jump. The bone models were registered to the biplanar radiographs, thereby reproducing the in vivo positions of the joint throughout the jump. ACL and bundle elongations were defined as the centroid to centroid distances between attachment sites for each knee position. ACL strain was defined as ACL length normalized to its length measured in the position of the knee at the time of MRI. Results: Peaks in ACL strain were observed before toe-off and 55 ± 35 milliseconds before initial ground contact. These peaks were associated with the knee positioned at low flexion angles. Mean ACL strain was inversely related to mean flexion angle (rho = −0.73, P < .001), such that ACL strain generally increased with knee extension throughout the jumping motion. ACL bundle lengths were significantly (rho > 0.85, P < .001) correlated with overall ACL length. Conclusion: These findings provide insight into how landing in extension can increase the risk of ACL injury. Specifically, this study shows that peak ACL strain can occur just before landing from a single-legged jump. Thus, when an individual lands on an extended knee, the ACL is relatively taut, which may make it particularly vulnerable to injury, especially in the presence of a movement perturbation or unanticipated change in landing strategy. Clinical Relevance: This study provides a novel measurement of dynamic ACL strain during an athletic maneuver and lends insight into how landing in extension can increase the likelihood of ACL failure.

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A Comparison of Knee Abduction Angles Measured by a 3D Anatomic Coordinate System Versus Videographic Analysis: Implications for Anterior Cruciate Ligament Injury

Cited by 9 publications

References 35 publications

Patellar Tendon Orientation and Strain Are Predictors of ACL Strain In Vivo During a Single-Leg Jump

Patellar Tendon Orientation and Strain Are Predictors of ACL Strain In Vivo During a Single-Leg Jump

In vivo attachment site to attachment site length and strain of the ACL and its bundles during the full gait cycle measured by MRI and high-speed biplanar radiography

In Vivo Anterior Cruciate Ligament Deformation During a Single-Legged Jump Measured by Magnetic Resonance Imaging and High-Speed Biplanar Radiography

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