Coupled Motions Under Compressive Load in Intact and ACL-Deficient Knees: A Cadaveric Study

2007 ◽  
Vol 129 (6) ◽  
pp. 818-824 ◽  
Author(s):  
David Liu-Barba ◽  
M. L. Hull ◽  
S. M. Howell
Keyword(s):  
Degrees Of Freedom ◽  
External Rotation ◽  
Cruciate Ligament ◽  
Compressive Loading ◽  
Compressive Load ◽  
Axial Rotation ◽  
Anterior Translation ◽  
Acl Deficient ◽  
Deficient Knee ◽  
Intact Knee

Knowledge of the coupled motions, which develop under compressive loading of the knee, is useful to determine which degrees of freedom should be included in the study of tibiofemoral contact and also to understand the role of the anterior cruciate ligament (ACL) in coupled motions. The objectives of this study were to measure the coupled motions of the intact knee and ACL-deficient knee under compression and to compare the coupled motions of the ACL-deficient knee with those of the intact knee. Ten intact cadaveric knees were tested by applying a 1600N compressive load and measuring coupled internal-external and varus-valgus rotations and anterior-posterior and medial-lateral translations at 0deg, 15deg, and 30deg of flexion. Compressive loads were applied along the functional axis of axial rotation, which coincides approximately with the mechanical axis of the tibia. The ACL was excised and the knees were tested again. In the intact knee, the peak coupled motions were 3.8deg internal rotation at 0deg flexion changing to −4.9deg external rotation at 30deg of flexion, 1.4deg of varus rotation at 0deg flexion changing to −1.9deg valgus rotation at 30deg of flexion, 1.4mm of medial translation at 0deg flexion increasing to 2.3mm at 30deg of flexion, and 5.3mm of anterior translation at 0deg flexion increasing to 10.2mm at 30deg of flexion. All changes in the peak coupled motions from 0degto30deg flexion were statistically significant (p<0.05). In ACL-deficient knees, there was a strong trend (marginally not significant, p=0.07) toward greater anterior translation (12.7mm) than that in intact knees (8.0mm), whereas coupled motions in the other degrees of freedom were comparable. Because the coupled motions in all four degrees of freedom in the intact knee and ACL-deficient knee are sufficiently large to substantially affect the tibiofemoral contact area, all degrees of freedom should be included when either developing mathematical models or designing mechanical testing equipment for study of tibiofemoral contact. The increase in coupled anterior translation in ACL-deficient knees indicates the important role played by the ACL in constraining anterior translation during compressive loading.

scholarly journals A biomechanical study after combined reconstruction of the anterior cruciate and anterolateral ligaments: Comparison between anatomic anterolateral ligament reconstruction and lateral tenodesis using the modified Lemaire technique

2020 ◽  
Vol 8 (2_suppl) ◽  
pp. 2325967120S0000
Author(s):  
Jean-Romain Delaloye ◽  
christoph Hartog ◽  
Samuel Blatter ◽  
Dominik Müller ◽  
Michel Schläppi ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Ligament Reconstruction ◽  
Cruciate Ligament ◽  
Anterolateral Ligament ◽  
The Other ◽  
Anterior Translation ◽  
Anterior Cruciate ◽  
Deficient Knee ◽  
Lemaire Procedure ◽  
Intact Knee

Objectives: To determine the stabilizing role of the anterolateral ligament reconstruction (ALLR) and the modified Lemaire lateral extraarticular tenodesis (LET) performed in combination with anterior cruciate ligament reconstruction (ACLR) and to determine if one of these two procedures was superior to the other. Methods: Six non paired cadaveric knees were tested with a 6 degrees of freedom robotic system (KUKA Robotics). Internal rotation and anterior tibial translation were measured between 0 and 90° knee flexion after applying 5 N-m Torque and a 134-N anterior load, respectively. A full kinematics assessment was performed in each following conditions: intact knee, after section of the anterior cruciate ligament (ACL), after section of the ACL and anterolateral ligament (ALL) and Kaplan fibers, after isolated ACLR, after combined ACLR+LET and ACLR+ALLR. ALLR was performed using Gracilis tendon while central strip of the ilio-tibial band was used for the modified Lemaire procedure. These different states were compared using a Tukey paired comparison test. Results: In combined ACL and anterolateral deficient knee, anterior translation and internal rotation remained significantly increased after isolated ACLR compared to intact knee (+2.33 ± 1.44 mm and +1.98 ± 1.06°; p > 0.01). On the other hand, the addition of an ALLR or a modified Lemaire LET to the ACLR allowed to restore anterior translation and internal rotation to values similar to the intact knee. Finally, the two anterolateral procedures had not significantly different values in both tests. This difference was 0.67 ± 1.46 mm for anterior translation (p=0.79) and 0.11 ± 1.11° for internal rotation (p=0.99). Conclusion: In ACL and anterolateral deficient knee, combined ACLR and anterolateral reconstruction allowed restoration of native stability of the knee in anterior translation and internal rotation contrary to isolated ACLR. Additionally, both types of extra-articular reconstruction, ALLR or modified Lemaire procedure, were similar in terms of restoring knee kinematics and neither overconstrained the knee.

scholarly journals Accuracy of magnetic resonance imaging for meniscal body tear in anterior cruciate ligament-deficient knees compared to anterior cruciate ligament-intact knee

2021 ◽  
Vol 2 ◽  
pp. 18-25
Author(s):  
Amit Joshi ◽  
Nagmani Singh ◽  
Bibek Basukala ◽  
Rohit Bista ◽  
Navin Tripathi ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Medial Meniscus ◽  
Cruciate Ligament ◽  
Lateral Meniscus ◽  
Meniscus Tear ◽  
Resonance Imaging ◽  
Anterior Cruciate ◽  
Acl Deficient ◽  
Deficient Knee ◽  
Intact Knee

Objectives: This prospective case–control study was conducted with primary aim to compare the value of magnetic resonance imaging (MRI) in terms of accuracy, sensitivity, specificity, positive predictive value, and negative predictive value for the detection of meniscal tear in anterior cruciate ligament (ACL)-deficient and ACL-intact groups. The secondary aim was to identify if the sensitivity and accuracy differ if the MRI is older than 3 months from the time of surgery. Materials and Methods: There were 255 patients enrolled into this study out of which 207 fulfilled the inclusion criteria. Among 207, 138 underwent surgery within 1 month of MRI, 30 had 1–3 months delay, and 39 cases underwent surgery more than 3 months after their MRI. Among 167 patients who underwent surgery within 3 months of MRI, 97 had ACL tear and 71 had intact ACL. Results: The overall sensitivity for lateral meniscus tear (68.2%) is significantly lower than the medial meniscus tear (92.9%). The sensitivity of MRI for medial meniscus tear in ACL-deficient knee is lower than ACL-intact knees (90% vs. 96.2%, P = 0.3). Similarly, the sensitivity is significantly lesser for lateral meniscus tear in ACL-deficient knee compared to ACL-intact knee (50% vs. 83.3%, P = 0.009). The sensitivity of MRI for both the lateral and medial meniscus tear decreased if the MRI performed 3 months before the surgery. Conclusion: Patients with ACL-deficient knee have to be counseled for intraoperative detection of lateral meniscus tear as the sensitivity of MRI for lateral meniscus tear in ACL-deficient group is low. Similarly, if the MRI is more than 3 months old from the time of surgery, we recommend to repeat the MRI as the sensitivity decreases significantly.

Importance of Tibial Slope for Stability of the Posterior Cruciate Ligament—Deficient Knee

2007 ◽  
Vol 35 (9) ◽  
pp. 1443-1449 ◽  
Author(s):  
J. Robert Giffin ◽  
Kathryne J. Stabile ◽  
Thore Zantop ◽  
Tracy M. Vogrin ◽  
Savio L-Y. Woo ◽  
...  
Keyword(s):  
Posterior Cruciate Ligament ◽  
Cruciate Ligament ◽  
Compressive Load ◽  
Tibial Slope ◽  
Anterior Tibial Translation ◽  
Posterior Tibial ◽  
Compressive Loads ◽  
Tibial Translation ◽  
Deficient Knee ◽  
Intact Knee

Background Previous studies have shown that increasing tibial slope can shift the resting position of the tibia anteriorly. As a result, sagittal osteotomies that alter slope have recently been proposed for treatment of posterior cruciate ligament (PCL) injuries. Hypotheses Increasing tibial slope with an osteotomy shifts the resting position anteriorly in a PCL-deficient knee, thereby partially reducing the posterior tibial “sag” associated with PCL injury. This shift in resting position from the increased slope causes a decrease in posterior tibial translation compared with the PCL-deficient knee in response to posterior tibial and axial compressive loads. Study Design Controlled laboratory study. Methods Three knee conditions were tested with a robotic universal force-moment sensor testing system: intact, PCL-deficient, and PCL-deficient with increased tibial slope. Tibial slope was increased via a 5-mm anterior opening wedge osteotomy. Three external loading conditions were applied to each knee condition at 0°, 30°, 60°, 90°, and 120° of knee flexion: (1) 134-N anterior-posterior (A-P) tibial load, (2) 200-N axial compressive load, and (3) combined 134-N A-P and 200-N axial loads. For each loading condition, kinematics of the intact knee were recorded for the remaining 5 degrees of freedom (ie, A-P, medial-lateral, and proximal-distal translations, internal-external and varus-valgus rotations). Results Posterior cruciate ligament deficiency resulted in a posterior shift of the tibial resting position to 8.4 ± 2.6 mm at 90° compared with the intact knee. After osteotomy, tibial slope increased from 9.2° ± 1.0° in the intact knee to 13.8° ± 0.9°. This increase in slope reduced the posterior sag of the PCL-deficient knee, shifting the resting position anteriorly to 4.0 ± 2.0 mm at 90°. Under a 200-N axial compressive load with the osteotomy, an additional increase in anterior tibial translation to 2.7 ± 1.7 mm at 30° was observed. Under a 134-N A-P load, the osteotomy did not significantly affect total A-P translation when compared with the PCL-deficient knee. However, because of the anterior shift in resting position, there was a relative decrease in posterior tibial translation and increase in anterior tibial translation. Conclusion Increasing tibial slope in a PCL-deficient knee reduces tibial sag by shifting the resting position of the tibia anteriorly. This sag is even further reduced when the knee is subjected to axial compressive loads. Clinical Relevance These data suggest that increasing tibial slope may be beneficial for patients with PCL-deficient knees.

scholarly journals Effect of meniscal root tear on pivot shift test after anterior cruciate ligament-deficient

2020 ◽  
Vol 8 (9_suppl7) ◽  
pp. 2325967120S0052
Author(s):  
Ming Zhou
Keyword(s):  
Pivot Shift ◽  
Cruciate Ligament ◽  
Lateral Meniscus ◽  
Pivot Shift Test ◽  
High Grade ◽  
Posterior Root ◽  
Meniscal Root Tear ◽  
Tibial Translation ◽  
Acl Deficient ◽  
Deficient Knee

Introduction: A review of the literature demonstrates that injury of the lateral meniscus, anterolateral capsule, and iliotibial(IT ) band or small lateral tibial plateau aggravate the instability of knee and contributes to a high-grade pivot shift in the ACL-deficient knee. Hypotheses: The hypothesis was that disruption of posterior root of the lateral meniscus will further destabilize the ACL-deficient knee and simulated a high-grade pivot shift but posterior root of medial meniscal not. Methods: 6 fresh-frozen cadaveric knees was performed the next test in a custom activity simulator.1.Determine the effect of PRLMT on the stability of ACL-deficient knee.In the pivot shift test, ITB force (50, 75, 100, 125, 150, and 175 N), internal rotation moments (1, 2, and 3 N.m),and valgus moments (5 and 7 N.m). tibial translation of front drawer test were performed by applying a 90-N anterior

scholarly journals Effects of Anterior Cruciate Ligament Deficiency on Tibiofemoral Cartilage Thickness and Strains in Response to Hopping

2018 ◽  
Vol 47 (1) ◽  
pp. 96-103 ◽  
Author(s):  
E. Grant Sutter ◽  
Betty Liu ◽  
Gangadhar M. Utturkar ◽  
Margaret R. Widmyer ◽  
Charles E. Spritzer ◽  
...  
Keyword(s):  
Cruciate Ligament ◽  
Acl Injury ◽  
Cartilage Thickness ◽  
Intercondylar Notch ◽  
Dynamic Activity ◽  
Acl Deficiency ◽  
Anterior Cruciate ◽  
Acl Deficient ◽  
Deficient Knee

Background: Changes in knee kinematics after anterior cruciate ligament (ACL) injury may alter loading of the cartilage and thus affect its homeostasis, potentially leading to the development of posttraumatic osteoarthritis. However, there are limited in vivo data to characterize local changes in cartilage thickness and strain in response to dynamic activity among patients with ACL deficiency. Purpose/Hypothesis: The purpose was to compare in vivo tibiofemoral cartilage thickness and cartilage strain resulting from dynamic activity between ACL-deficient and intact contralateral knees. It was hypothesized that ACL-deficient knees would show localized reductions in cartilage thickness and elevated cartilage strains. Study Design: Controlled laboratory study. Methods: Magnetic resonance images were obtained before and after single-legged hopping on injured and uninjured knees among 8 patients with unilateral ACL rupture. Three-dimensional models of the bones and articular surfaces were created from the pre- and postactivity scans. The pre- and postactivity models were registered to each other, and cartilage strain (defined as the normalized difference in cartilage thickness pre- and postactivity) was calculated in regions across the tibial plateau, femoral condyles, and femoral cartilage adjacent to the medial intercondylar notch. These measurements were compared between ACL-deficient and intact knees. Differences in cartilage thickness and strain between knees were tested with multiple analysis of variance models with alpha set at P < .05. Results: Compressive strain in the intercondylar notch was elevated in the ACL-deficient knee relative to the uninjured knee. Furthermore, cartilage in the intercondylar notch and adjacent medial tibia was significantly thinner before activity in the ACL-deficient knee versus the intact knee. In these 2 regions, thinning was significantly influenced by time since injury, with patients with more chronic ACL deficiency (>1 year since injury) experiencing greater thinning. Conclusion: Among patients with ACL deficiency, the medial femoral condyle adjacent to the intercondylar notch in the ACL-deficient knee exhibited elevated cartilage strain and loss of cartilage thickness, particularly with longer time from injury. It is hypothesized that these changes may be related to posttraumatic osteoarthritis development. Clinical Relevance: This study suggests that altered mechanical loading is related to localized cartilage thinning after ACL injury.

scholarly journals Different anterolateral procedures have variable impact on knee kinematics and stability when performed in combination with anterior cruciate ligament reconstruction

2020 ◽  
pp. jisakos-2019-000360
Author(s):  
Thomas Neri ◽  
Danè Dabirrahmani ◽  
Aaron Beach ◽  
Samuel Grasso ◽  
Sven Putnis ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Ligament Reconstruction ◽  
Cruciate Ligament ◽  
Knee Kinematics ◽  
Rotational Laxity ◽  
Level Of Evidence ◽  
Cruciate Ligament Reconstruction ◽  
Anterior Cruciate ◽  
Deficient Knee ◽  
Intact Knee

ObjectiveThe optimal anterolateral procedure to control anterolateral rotational laxity of the knee is still unknown. The objective was to compare the ability of five anterolateral procedures performed in combination with anterior cruciate ligament reconstruction (ACLR) to restore native knee kinematics in the setting of a deficient anterior cruciate ligament (ACL) and anterolateral structures.MethodsA controlled laboratory study was performed using 10 fresh-frozen cadaveric whole lower limbs with intact iliotibial band. Kinematics from 0° to 90° of flexion were recorded using a motion analysis three-dimensional (3D) optoelectronic system, allowing assessment of internal rotation (IR) and anteroposterior (AP) tibial translation at 30° and 90° of flexion. Joint centres and bony landmarks were calculated from 3D bone models obtained from CT scans. Intact knee kinematics were assessed initially, followed by sequential section of the ACL and anterolateral structures (anterolateral ligament, anterolateral capsule and Kaplan fibres). After ACLR, five anterolateral procedures were performed consecutively on the same knee: ALLR, modified Ellison, deep Lemaire, superficial Lemaire and modified MacIntosh. The last three procedures were randomised. For each procedure, the graft was fixed in neutral rotation at 30° of flexion and with a tension of 20 N.ResultsIsolated ACLR did not restore normal overall knee kinematics in a combined ACL plus anterolateral-deficient knee, leaving a residual tibial rotational laxity (p=0.034). Only the ALLR (p=0.661) and modified Ellison procedure (p=0.641) restored overall IR kinematics to the normal intact state. Superficial and deep Lemaire and modified MacIntosh tenodeses overconstrained IR, leading to shifted and different kinematics compared with the intact condition (p=0.004, p=0.001 and p=0.045, respectively). Compared with ACLR state, addition of an anterolateral procedure did not induce any additional control on AP translation at 30° and 90° of flexion (all p>0.05), except for the superficial Lemaire procedure at 90° (p=0.032).ConclusionIn biomechanical in vitro setting, a comparison of five anterolateral procedures revealed that addition of either ALLR or modified Ellison procedure restored overall native knee kinematics in a combined ACL plus anterolateral-deficient knee. Superficial and deep Lemaire and modified MacIntosh tenodeses achieved excellent rotational control but overconstrained IR, leading to a change from intact knee kinematics.Level of evidenceThe level-of-evidence statement does not apply for this laboratory experiments study.

Characterization of a Biomechanical Animal Model for Intact Knee Kinematics and ACL Function Using 6-DOF Robotic Technology

2011 ◽  
Author(s):  
Daniel V. Boguszewski ◽  
Safa T. Herfat ◽  
Christopher T. Wagner ◽  
David L. Butler ◽  
Jason T. Shearn
Keyword(s):  
Animal Model ◽  
Degrees Of Freedom ◽  
Cruciate Ligament ◽  
Knee Kinematics ◽  
Biomechanical Model ◽  
Ligament Injury ◽  
Joint Stability ◽  
Robotic Technology ◽  
Anterior Cruciate ◽  
Intact Knee

Anterior cruciate ligament injury (ACL) affects an estimated 250,000 people annually [1]. Unfortunately, even with ACL reconstruction, the likely prognosis is long-term osteoarthritis (OA) [2]. Many strides have been made in attempting to understand and improve this outcome. The use of robotic technology has provided an avenue for researchers to examine the ACL’s role in knee joint stability in all six anatomical degrees of freedom (DOF) [3]. The overall goal of our lab robotics research is to use this technology to understand ACL function during activities of daily living (ADLs) in hopes of developing a biomechanical animal model which can be used as a preclinical tool to design new repair methods and materials. We have examined three species (ovine, porcine, and human), measuring all forces and moments produced from displacement control motion paths developed for cyclic testing in a robotic system (KUKA; KR210). This information will provide a basis for comparing intact knee biomechanics and ACL function across species. With these robotic inputs, we have performed a series of studies to aid in the development of a biomechanical model of the human knee.

Using Robotic Testing System to Investigate ACL Reconstructions in Restoring the Normal Knee Joint Biomechanics: Experience at Harvard Medical School

2011 ◽  
Author(s):  
Guoan Li ◽  
Hemanth R. Gadikota ◽  
Thomas J. Gill
Keyword(s):  
Knee Joint ◽  
Acl Reconstruction ◽  
Degrees Of Freedom ◽  
Cruciate Ligament ◽  
Surgical Techniques ◽  
Standard Of Care ◽  
Axial Rotation ◽  
Anatomical Reconstruction ◽  
Single Bundle ◽  
Normal Knee

Rupture of the anterior cruciate ligament (ACL) is a debilitating injury associated with various complications such as joint instability, meniscal injury and chronically may lead to osteoarthritis. ACL is believed to be the primary restraint to anterior translation and axial rotation. However, few studies have investigated the alterations to the other degrees of freedom kinematics due to ACL deficiency. ACL reconstruction has been widely accepted to be the standard of care for patients who sustain an ACL rupture to minimize the risk of the complications mentioned above. Widely practiced surgical techniques have yet to prove their efficacy in comprehensively restoring the normal knee joint function. Sub-optimal performance of the conventional single bundle ACL reconstruction has sparked a renewed interest in anatomical reconstruction and alterations to the conventional techniques.

Kinematic Analysis of Lateral Meniscal Oblique Radial Tears in the Anterior Cruciate Ligament–Deficient Knee

2021 ◽  
pp. 036354652110525
Author(s):  
Patrick A. Smith ◽  
Will A. Bezold ◽  
Cristi R. Cook ◽  
Aaron J. Krych ◽  
Michael J. Stuart ◽  
...  
Keyword(s):  
Pivot Shift ◽  
Cruciate Ligament ◽  
Joint Stability ◽  
Meniscal Extrusion ◽  
Anterior Drawer ◽  
Anterior Translation ◽  
Meniscus Root ◽  
Acl Deficiency ◽  
Anterior Cruciate ◽  
Acl Deficient

Background: Lateral meniscal oblique radial tears (LMORT) occur frequently in conjunction with anterior cruciate ligament (ACL) disruption and are anatomically distinct from meniscus root tears. Hypothesis/Purpose: The purpose of this study was to characterize the effects of LMORT types 3 (LMORT3) and 4 (LMORT4) lesions on joint stability and meniscal extrusion in ACL-deficient knees. Our hypothesis was that both lesions would promote significant increases in anterior translation and meniscal extrusion, with the LMORT4 lesion having a greater effect. Study Design: Controlled laboratory study. Methods: Two matched pairs of cadaveric knees (n = 4) were used to optimize the testing sequence. Additional cadaveric knees with LMORT3 (n = 8) and LMORT4 (n = 8) lesions created after ACL transection underwent robotic kinematic testing for anterior drawer and pivot-shift simulations with associated ultrasound-measured meniscal extrusion at clinically relevant knee flexion angles. Results: Optimization testing showed no differences on the effect of LMORT4 lesions for anterior translation and lateral meniscal extrusion with ACL-intact versus ACL-deficient knees. ACL deficiency and LMORT3 and LMORT4 lesions with ACL deficiency were associated with significantly greater anterior translation compared with ACL-intact state for both anterior drawer and pivot-shift testing at all flexion angles ( P < .001). ACL deficiency with either LMORT3 or LMORT4 lesion was associated with significantly greater anterior translation than was ACL deficiency only ( P < .005) for anterior drawer testing at 90° of flexion. Meniscal extrusion was greater with LMORT3 and LMORT4 lesions compared with ACL deficiency only ( P < .05) for anterior drawer at 60° of flexion and for pivot shift at 15° of flexion. The LMORT4 lesion demonstrated increased anterior translation for anterior drawer ( P = .003) at 60° of flexion (12%) as well as for pivot shift at 15° of flexion (7%) and 30° of flexion (13%) ( P < .005) compared with ACL deficiency only. Conclusion: In this cadaveric model, the addition of an LMORT3 or LMORT4 lesion increased anterior laxity for both the anterior drawer and the pivot shift when compared with an isolated ACL tear. Lateral meniscal extrusion was also exacerbated by these LMORT lesions. Clinical Relevance: LMORT lesions, distinct from meniscus root tears, occur frequently in conjunction with ACL tears. This study characterized the biomechanical consequences of LMORT3 and LMORT4 lesions on joint stability and meniscal function, highlighting the importance of diagnosing and treating LMORT lesions at the time of ACL reconstruction.

Effect of Femoral Antetorsion on Tibiofemoral Translation and Rotation in the Anterior Cruciate Ligament Deficient Knee

2018 ◽  
Vol 32 (10) ◽  
pp. 960-965
Author(s):  
Mohamed Omar ◽  
Yousif Al Saiegh ◽  
Emmanouil Liodakis ◽  
Timo Stuebig ◽  
Daniel Guenther ◽  
...  
Keyword(s):  
Distal Femur ◽  
Pivot Shift ◽  
Cruciate Ligament ◽  
Anterior Tibial Translation ◽  
Tibial Rotation ◽  
Femoral Antetorsion ◽  
Anterior Drawer ◽  
Tibial Translation ◽  
Acl Deficient ◽  
Deficient Knee

AbstractWe aimed to investigate how increased or decreased femoral antetorsion would affect the biomechanics of the knee in an anterior cruciate ligament (ACL)-deficient cadaveric model. We hypothesized that external or internal rotation of the distal femur, achieved through a femoral osteotomy, would affect the magnitude of tibiofemoral translation and rotation. Navigated measurements of tibiofemoral translation and rotation during the anterior drawer, Lachman, and pivot shift tests were performed on six whole-body cadaveric specimens in each of the following four conditions: native, ACL-deficient knee, ACL-deficient knee and 20-degree internal distal femur rotation, and ACL-deficient knee and 20-degree external distal femur rotation. Increased femoral antetorsion significantly reduced anterior tibial translation in the ACL-deficient knee during the anterior drawer, Lachman, and pivot shift tests (p < 0.05). Conversely, decreasing femoral antetorsion resulted in an increase in anterior tibial translation in the anterior drawer (nonsignificant), Lachman (p < 0.05), and pivot shift (p < 0.05) tests. Internally rotating the distal femur significantly reduced the magnitude of tibial rotation during the pivot shift test in the ACL-deficient knee (p < 0.05), whereas external rotation of the distal femur significantly increased tibial rotation (p < 0.05). The magnitude of femoral antetorsion affects tibiofemoral translation in an ACL-deficient cadaveric mode. Internally rotating the distal femur 20 degrees reduced the magnitude of tibial translation and rotation similar to that of the native knee, whereas externally rotating the distal femur aggravated translational and rotational instability.

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