The Coupled Motion of the Femur and Patella During In Vivo Weightbearing Knee Flexion

2007 ◽  
Vol 129 (6) ◽  
pp. 937-943 ◽  
Author(s):  
Guoan Li ◽  
Ramprasad Papannagari ◽  
Kyung Wook Nha ◽  
Louis E. DeFrate ◽  
Thomas J. Gill ◽  
...  
Keyword(s):  
Knee Joint ◽  
Knee Flexion ◽  
External Rotation ◽  
Full Range ◽  
Surgical Techniques ◽  
Base Line ◽  
Strongly Correlated ◽  
Patellar Tilt ◽  
Coupled Motion ◽  
Kinematic Coupling

The movement of the knee joint consists of a coupled motion between the tibiofemoral and patellofemoral articulations. This study measured the six degrees-of-freedom kinematics of the tibia, femur, and patella using dual-orthogonal fluoroscopy and magnetic resonance imaging. Ten normal knees from ten living subjects were investigated during weightbearing flexion from full extension to maximum flexion. The femoral and the patellar motions were measured relative to the tibia. The femur externally rotated by 12.9deg and the patella tilted laterally by 16.3deg during the full range of knee flexion. Knee flexion was strongly correlated with patellar flexion (R2=0.91), posterior femoral translation was strongly correlated to the posterior patellar translation (R2=0.87), and internal-external rotation of the femur was correlated to patellar tilt (R2=0.73) and medial-lateral patellar translation (R2=0.63). These data quantitatively indicate a kinematic coupling between the tibia, femur, and patella, and provide base line information on normal knee joint kinematics throughout the full range of weightbearing flexion. The data also suggest that the kinematic coupling of tibia, femur, and patella should be considered when investigating patellar pathologies and when developing surgical techniques to treat knee joint diseases.

The Effects of Removal and Reconstruction of the Anterior Cruciate Ligament on Patellofemoral Kinematics

1998 ◽  
Vol 26 (2) ◽  
pp. 201-209 ◽  
Author(s):  
Yeou-Fang Hsieh ◽  
Louis F. Draganich ◽  
Sherwin H. Ho ◽  
Bruce Reider
Keyword(s):  
Anterior Cruciate Ligament ◽  
Knee Flexion ◽  
External Rotation ◽  
Cruciate Ligament ◽  
Anterior Tibial Translation ◽  
Tibial Rotation ◽  
Patellar Tilt ◽  
Anterior Cruciate ◽  
Tibial Translation ◽  
Intact Knee

Patellofemoral pain may be associated with anterior cruciate ligament deficiency or may occur after anterior cruciate ligament reconstruction. We investigated the effects of the removal and reconstruction of the anterior cruciate ligament on the kinematics of the tibiofemoral and patellofemoral joints during physiologic levels of quadriceps muscle loads in seven cadaveric knees. A bone-patellar tendon-bone graft was used for intraarticular reconstruction of the anterior cruciate ligament. The spatial positions of the tibiofemoral and patellofemoral joints were measured between 0° and 90° of knee flexion in 15° increments with a six degree-of-freedom digitizing system. Excision of the anterior cruciate ligament resulted in statistically significant increases in anterior tibial translation between 0° and 90° and valgus tibial rotation between 30° and 90°; intraarticular reconstruction returned these to levels not significantly different from those of the intact knee. Excision of the anterior cruciate ligament resulted in significant increases in lateral patellar tilt, ranging from 6.3° to 9.0° between full extension and 90° of knee flexion, and in lateral patellar shift, ranging from 2.9 mm at 15° of knee flexion to 5.9 mm at 90°; intraarticular reconstruction returned these to levels not significantly different from those of the intact knee. Neither removal nor reconstruction of the anterior cruciate ligament significantly affected tibial internal-external rotation, patellar flexion, patellar mediolateral rotation, patellar anteroposterior translation, or patellar proximodistal translation.

scholarly journals Arthroscopic lateral retinacular release improves patello-femoral and femoro-tibial kinematics in patients with isolated lateral retinacular tightness

2021 ◽  
Author(s):  
Florian Pohlig ◽  
Ulrich Lenze ◽  
Florian Walter Lenze ◽  
Igor Lazic ◽  
Alexander Haug ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Contact Area ◽  
Tilt Angle ◽  
Knee Flexion ◽  
Full Range ◽  
Tibial Rotation ◽  
Lateral Retinacular Release ◽  
Patellar Tilt ◽  
Patellar Shift ◽  
Tibial Kinematics

Abstract Purpose Arthroscopic lateral retinacular release (LRR) has long been considered the gold standard for the treatment for anterior knee pain caused by lateral retinacular tightness (LRT). However, one-third of patients experience continuous pain postoperatively, which is thought to be related to persistent maltracking of the patella and altered femoro-tibial kinematics. Therefore, the aim of the present study was to simultaneously assess femoro-tibial and patello-femoral kinematics and identify the influence of arthroscopic LRR. Methods Sixteen healthy volunteers and 12 patients with unilateral, isolated LRT were prospectively included. Open MRI scans with and without isometric quadriceps contraction were performed in 0°, 30° and 90° of knee flexion preoperatively and at 12 months after surgery. Patellar shift, tilt angle, patello-femoral contact area and magnitude of femoro-tibial rotation were calculated by digital image processing. Results Postoperatively, patellar shift was significantly reduced at 90° of knee flexion compared to preoperative values. The postoperative patellar tilt angle was found to be significantly smaller at 30° of knee flexion compared to that preoperatively. Isometric muscle contractions did not considerably influence patellar shift or tilt in either group. The patello-femoral contact area increased after LRR over the full range of motion (ROM), with significant changes at 0° and 90°. Regarding femoro-tibial kinematics, significantly increased femoral internal rotation at 0° was observed in the patient group preoperatively, whereas the magnitude of rotation at 90° of knee flexion was comparable to that of healthy individuals. The pathologically increased femoral internal rotation at 30° without muscular activity could be significantly decreased by LRR. With isometric quadriceps contraction no considerable improvement of femoral internal rotation could be achieved by LRR at 30° of knee flexion. Conclusions Patello-femoral and femoro-tibial joint kinematics could be improved, making LRR a viable surgical option in carefully selected patients with isolated LRT. However, pathologically increased femoral internal rotation during early knee flexion remained unaffected by LRR and thus potentially accounts for persistent pain. Level of evidence II.

scholarly journals How Specific Are Learning Disabilities?

2021 ◽  
pp. 002221942098298
Author(s):  
Robin L. Peterson ◽  
Lauren M. McGrath ◽  
Erik G. Willcutt ◽  
Janice M. Keenan ◽  
Richard K. Olson ◽  
...  
Keyword(s):  
Learning Disabilities ◽  
Reading Comprehension ◽  
Full Range ◽  
Written Expression ◽  
Strongly Correlated ◽  
Math Problem Solving ◽  
Confirmatory Factor ◽  
Bifactor Models ◽  
And Mathematics ◽  
Specific Learning

Despite historical emphasis on “specific” learning disabilities (SLDs), academic skills are strongly correlated across the curriculum. Thus, one can ask how specific SLDs truly are. To answer this question, we used bifactor models to identify variance shared across academic domains (academic g), as well as variance unique to reading, mathematics, and writing. Participants included 686 children aged 8 to 16. Although the sample was overselected for learning disabilities, we intentionally included children across the full range of individual differences in this study in response to growing recognition that a dimensional, quantitative view of SLD is more accurate than a categorical view. Confirmatory factor analysis identified five academic domains (basic reading, reading comprehension, basic math, math problem-solving, and written expression); spelling clustered with basic reading and not writing. In the bifactor model, all measures loaded significantly on academic g. Basic reading and mathematics maintained variance distinct from academic g, consistent with the notion of SLDs in these domains. Writing did not maintain specific variance apart from academic g, and evidence for reading comprehension-specific variance was mixed. Academic g was strongly correlated with cognitive g ( r = .72) but not identical to it. Implications for SLD diagnosis are discussed.

Biomechanical Analysis of an Isolated Fibular (Lateral) Collateral Ligament Reconstruction Using an Autogenous Semitendinosus Graft

2007 ◽  
Vol 35 (9) ◽  
pp. 1521-1527 ◽  
Author(s):  
Benjamin R. Coobs ◽  
Robert F. LaPrade ◽  
Chad J. Griffith ◽  
Bradley J. Nelson
Keyword(s):  
Internal Rotation ◽  
Knee Flexion ◽  
Ligament Reconstruction ◽  
External Rotation ◽  
Anatomic Reconstruction ◽  
Ligament Injury ◽  
Collateral Ligament ◽  
Fibular Collateral Ligament ◽  
Normal Stability ◽  
Semitendinosus Graft

Background The fibular collateral ligament is the primary stabilizer to varus instability of the knee. Untreated fibular collateral ligament injuries can lead to residual knee instability and can increase the risk of concurrent cruciate ligament reconstruction graft failures. Anatomic reconstructions of the fibular collateral ligament have not been biomechanically validated. Purpose To describe an anatomic fibular collateral ligament reconstruction using an autogenous semitendinosus graft and to test the hypothesis that using this reconstruction technique to treat an isolated fibular collateral ligament injury will restore the knee to near normal stability. Study Design Controlled laboratory study. Methods Ten nonpaired, fresh-frozen cadaveric knees were biomechanically subjected to a 10 N·m varus moment and 5 N·m external and internal rotation torques at 0°, 15°, 30°, 60°, and 90° of knee flexion. Testing was performed with an intact and sectioned fibular collateral ligament, and also after an anatomic reconstruction of the fibular collateral ligament with an autogenous semitendinosus graft. Motion changes were assessed with a 6 degree of freedom electromagnetic motion analysis system. Results After sectioning, we found significant increases in varus rotation at 0°, 15°, 30°, 60°, and 90°, external rotation at 60° and 90°, and internal rotation at 0°, 15°, 30°, 60°, and 90° of knee flexion. After reconstruction, there were significant decreases in motion in varus rotation at 0°, 15°, 30°, 60°, and 90°, external rotation at 60° and 90°, and internal rotation at 0°, 15°, and 30° of knee flexion. In addition, we observed a full recovery of knee stability in varus rotation at 0°, 60°, and 90°, external rotation at 60° and 90°, and internal rotation at 0° and 30° of knee flexion. Conclusion An anatomic fibular collateral ligament reconstruction restores varus, external, and internal rotation to near normal stability in a knee with an isolated fibular collateral ligament injury. Clinical Significance An anatomic reconstruction of the fibular collateral ligament with an autogenous semitendinosus graft is a viable option to treat nonrepairable acute or chronic fibular collateral ligament tears in patients with varus instability.

Biomechanical Comparison of Kinematic and Mechanical Knee Alignment Techniques in a Computer Simulation Medial Pivot Total Knee Arthroplasty Model

2021 ◽  
Author(s):  
Young Dong Song ◽  
Shinichiro Nakamura ◽  
Shinichi Kuriyama ◽  
Kohei Nishitani ◽  
Hiromu Ito ◽  
...  
Keyword(s):  
Femoral Component ◽  
Knee Flexion ◽  
External Rotation ◽  
Knee Kinematics ◽  
Lateral Compartment ◽  
Contact Stresses ◽  
Contact Forces ◽  
Medial Compartment ◽  
Tibial Insert ◽  
Medial Pivot

AbstractSeveral concepts may be used to restore normal knee kinematics after total knee arthroplasty. One is a kinematically aligned (KA) technique, which restores the native joint line and limb alignment, and the other is the use of a medial pivot knee (MPK) design, with a ball and socket joint in the medial compartment. This study aimed to compare motions, contact forces, and contact stress between mechanically aligned (MA) and KA (medial tilt 3° [KA3] and 5° [KA5]) models in MPK. An MPK design was virtually implanted with MA, KA3, and KA5 in a validated musculoskeletal computer model of a healthy knee, and the simulation of motion and contact forces was implemented. Anteroposterior (AP) positions, mediolateral positions, external rotation angles of the femoral component relative to the tibial insert, and tibiofemoral contact forces were evaluated at different knee flexion angles. Contact stresses on the tibial insert were calculated using finite element analysis. The AP position at the medial compartment was consistent for all models. From 0° to 120°, the femoral component in KA models showed larger posterior movement at the lateral compartment (0.3, 6.8, and 17.7 mm in MA, KA3, and KA5 models, respectively) and larger external rotation (4.2°, 12.0°, and 16.8° in the MA, KA3, and KA5 models, respectively) relative to the tibial component. Concerning the mediolateral position of the femoral component, the KA5 model was positioned more medially. The contact forces at the lateral compartment of all models were larger than those at the medial compartment at >60° of knee flexion. The peak contact stresses on the tibiofemoral joint at 90° and 120° of knee flexion were higher in the KA models. However, the peak contact stresses of the KA models at every flexion angle were <20 MPa. The KA technique in MPK can successfully achieve near-normal knee kinematics; however, there may be a concern for higher contact stresses on the tibial insert.

scholarly journals Neuromuscular Control of the Knee during a Resisted Single-Limb Squat Exercise

2005 ◽  
Vol 33 (10) ◽  
pp. 1520-1526 ◽  
Author(s):  
Richard K. Shields ◽  
Sangeetha Madhavan ◽  
Emy Gregg ◽  
Jennifer Leitch ◽  
Ben Petersen ◽  
...  
Keyword(s):  
Body Weight ◽  
Knee Joint ◽  
Knee Flexion ◽  
Neuromuscular Control ◽  
Biceps Femoris ◽  
Medial Gastrocnemius ◽  
Isometric Contractions ◽  
Low Resistance ◽  
Squat Exercise ◽  
Flexion And Extension

Background Closed kinetic chain exercises such as single-limb squats are preferred for knee rehabilitation. A complete understanding of the neuromuscular control of the knee during the single-limb squat is essential to increase the efficiency of rehabilitation programs. Hypothesis Performing a controlled single-limb squat with resistance to knee flexion and extension will increase the coactivation of the hamstring muscle group, thus reducing the quadriceps/hamstrings ratio. Study Design Descriptive laboratory study. Methods A total of 15 healthy human subjects (7 women, 8 men) performed controlled single-limb squats in a custom mechanical device that provided resistance to both flexion and extension. Subjects performed the task at 3 levels of resistance, set as a percentage of body weight. Surface electromyographic recordings from 7 muscles (gluteus medius, rectus femoris, vastus medialis oblique, vastus lateralis, biceps femoris, semitendinosus, and medial gastrocnemius) were collected during the task. Results Biceps femoris activity during knee flexion increased from approximately 12% maximum voluntary isometric contractions during low resistance (0% body weight) to approximately 27% maximum voluntary isometric contractions during high resistance (8% body weight). Although the quadriceps had greater activity than the hamstrings at all levels of resistance, the quadriceps/hamstrings ratio declined significantly with resistance (F2,27 = 29.05; P=. 012) from 3.0 at low resistance to 2.32 at the highest resistance. Conclusions Performing controlled resisted single-limb squats may help to simultaneously strengthen the quadriceps and facilitate coactivation of the hamstrings, thus reducing anterior tibial shear forces. The coactivation may also increase the dynamic control of the knee joint. Clinical Relevance The typical single-limb squat exercise performed in the clinic does not usually control for bidirectional resistance and knee joint excursion. As seen in this study, controlled single-limb squats at increased levels of resistance help to increase the coactivation of the hamstring muscles, which is essential to optimize neuromuscular control of the knee.

The effect of patient positioning on the accuracy and reliability of assessment of knee range of motion over a telemedicine platform

2021 ◽  
pp. 1357633X2110467
Author(s):  
Sean Wei Loong Ho ◽  
Kelvin Guoping Tan ◽  
Eng Chuan Neoh ◽  
Jiayen Wong ◽  
Atiq Syazwani Roslan ◽  
...  
Keyword(s):  
Knee Joint ◽  
Range Of Motion ◽  
Supine Position ◽  
Knee Flexion ◽  
Patient Positioning ◽  
Flexion Angle ◽  
Visual Estimation ◽  
Limits Of Agreement ◽  
Joint Range Of Motion ◽  
Joint Range

Introduction Diagnostic accuracy is one of the key considerations of telemedicine usage in orthopedic surgery. The aim of this study was to determine the optimal patient positioning to achieve accurate and reliable visual estimation of the knee joint range of motion over a digital platform for telemedicine. Methods A single volunteer was recruited to perform a total of 120 discrete and random knee range of motion angles in three patient positions: sitting, standing and supine. The patient image was broadcast over a digital platform to six raters. The raters recorded their visual estimation of each discrete knee flexion angle independently. After each discrete knee flexion angle, a physical goniometer was used to obtain the actual flexion angle of the knee. Results A total of 120 discrete measurements (40 measurements in the sitting, standing, and supine positions each) were recorded by each of the six raters. The supine position resulted in the highest intraclass correlation of 0.97 (95% confidence interval: 0.98, 0.99). All three patient positions achieved low absolute difference between the goniometer and the raters with 5.6 degrees (95% limits of agreement: −21.0, 9.8) in sitting, 2.7 degrees (95% limits of agreement: −10.1, 15.4), and 1.2 degrees (95% limits of agreement: −9.8, 12.3) in the supine position. The supine position had the highest accuracy and reliability. Discussion Visual estimation of the knee joint range of motion over telemedicine is clinically accurate and reliable. Patients should be assessed in a supine position to obtain the highest accuracy and reliability for visual estimation of the knee joint range of motion during telemedicine.

scholarly journals Dynamic anterior shoulder stabilization using the long head of the biceps tendon: a biomechanical study: DAS: a biomechanical study

2019 ◽  
Vol 7 (5_suppl3) ◽  
pp. 2325967119S0020
Author(s):  
J. Mehl ◽  
F. Imhoff ◽  
E. Obopilwe ◽  
F. Dyrna ◽  
A. Lädermann ◽  
...  
Keyword(s):  
External Rotation ◽  
Biceps Tendon ◽  
Surgical Techniques ◽  
Biomechanical Study ◽  
Bankart Repair ◽  
Shoulder Stabilization ◽  
Glenoid Defect ◽  
Defect Groups ◽  
Anterior Glenoid ◽  
Long Head

Objectives A new concept of dynamic anterior shoulder stabilization (DAS) combining Bankart repair with the additional sling effect of the long head of the biceps (LHB) tendon to treat anterior glenohumeral instability has recently been introduced. The purpose of this study was to biomechanically investigate the stabilizing effect of the DAS technique in comparison to standard Bankart repair in different defect models. Methods Twenty-four fresh frozen cadaver shoulders (average ± SD: age 60.1 ± 8.6 years) were mounted in a shoulder-testing system allowing 6 degrees of freedom. According to cross sectional area ratios the rotator cuff muscles and the LHB tendon were loaded with 40 N and 10 N, respectively. Glenohumeral translation was tested in 60° abduction and 60° external rotation (ABER position) while forces of 20 N, 30 N and 40 N were applied. The translation was measured using a 3D-digitizer and the total translation and the relative translation in relation to the native starting position were determined. Maximal external and internal rotation after application of 1.5 Nm torque to the humerus were measured. All specimens went through for 4 different conditions (Intact, defect, isolated Bankart repair, DAS) and were randomized to 3 different defect groups (Isolated Bankart lesion; 10% anterior glenoid defect; 20% anterior glenoid defect). Results Both surgical techniques resulted in decreased anterior glenohumeral translation in comparison to the defect conditions in all defect groups. In comparison with isolated Bankart repair DAS showed significant less relative anterior translation in 10% glenoid defects (30 N: 2.6 ± 3.4 mm vs. 5.3 ± 4.2 mm; p=0.044) and in 20% glenoid defects (40 N: 2.1 ± 6.6 mm vs. 6.0 ± 5.7 mm; p=0.035). However, in 20% defects DAS led to a relevant posterior and inferior shift of the humeral head in ABER position and to a relevant increase of inferior glenohumeral translation. Both surgical techniques did not limit the rotational range of motion. Conclusion In the context of minor glenoid bone defects the DAS technique demonstrates superior results in comparison to isolated Bankart repair.

Posteromedial Ligament Repair of the Knee With Suture Tape Augmentation: A Biomechanical Study

2019 ◽  
Vol 47 (12) ◽  
pp. 2952-2959 ◽  
Author(s):  
Julian T. Mehl ◽  
Cameron Kia ◽  
Matthew Murphy ◽  
Elifho Obopilwe ◽  
Mark Cote ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Knee Flexion ◽  
Primary Repair ◽  
Cruciate Ligament ◽  
Surgical Techniques ◽  
Ligament Repair ◽  
Acl Injuries ◽  
Tendon Reconstruction ◽  
Reasonable Alternative ◽  
Suture Tape

Background: In cases of acute combined posteromedial and anterior cruciate ligament (ACL) injuries, primary repair of the superficial medial collateral ligament (sMCL) and posterior oblique ligament (POL) with suture tape augmentation may be a reasonable alternative to standard tendon reconstruction techniques. Purpose/Hypothesis: The purpose was to examine the rotational and valgus laxity with ACL strain following sMCL and POL repair with suture tape augmentation at various degrees of knee flexion. It was hypothesized that this technique would restore knee laxity and kinematics comparable with those of the intact state. Study Design: Controlled laboratory study. Methods: Ten cadaveric knee specimens (mean ± SD, 57.9 ± 5.9 years) were obtained. Specimens were tested with the tibia fixed and the femur mobile on an X-Y table. Each specimen was tested in 4 conditions according to the state of the sMCL and POL: native, deficient, repaired with suture tape augmentation, and reconstructed with tendon allografts. Valgus laxity was tested with 40-N force applied in the lateral direction of the femur, and rotational motion was tested with 5-N torque applied to the tibia. ACL strain during valgus stress was also measured. Each condition was tested in 0°, 15°, 30°, 45°, and 60° of knee flexion. Results: Dissection of the sMCL and POL led to significantly increased valgus laxity in all flexion angles, with a significant increase in ACL strain at 30° ( P < .001) and 45° ( P < .001). Ligament repair with suture tape augmentation demonstrated similar valgus and rotational laxity as compared with intact specimens, with the exception of increased internal rotation at 30° ( P = .005). Ligament reconstruction resulted in significantly increased valgus opening at 45° ( P = .048) and significantly increased internal rotation at 30° ( P < .001) as compared with the native state. Direct comparison between surgical techniques showed no significant differences. Conclusion: At time zero, ligament repair of the posteromedial knee with suture tape augmentation restored close-to-native valgus and rotatory laxity, as well as native ACL strain for cases of complete sMCL and POL avulsion. Clinical Relevance: Ligament repair of the sMCL and POL with suture tape augmentation may be a reasonable alternative to tendon reconstruction techniques in cases of acute combined posteromedial and ACL injuries with valgus and rotatory instability.

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