Effects of bone shapes and ligaments attachements on to passive knee motions

Creating three dimensional dynamic human knee model and investigating the reasons of problems after surgical treatment are the subjects which has been studying by many investigators. The aim of the study was determining the primer structures which effect on passive movement on human knee joint. The tibio-femoral joint model was created by guidance of literature and then it is simulated by using ADAMS package. Some of the ligament bundles were seen to elongate negligibly. Therefore simulation was repeated by assuming these bundles as inextensible links. During the simulation contact points were traced. Contact forces were defined between the traces and tibial plateau and it was resimulated. As a result the anterior bundle of anterior, posterior cruciates and medial collateral ligaments (MCL) and deep portion of MCL played an important role on shaping the bones which form the knee joint. The ligament surgeries should be developed by considering the ligament bundle reconstructions to reduce the unwanted side effects after the surgery

Three-dimensional knee model: Constrained by isometric ligament bundles and experimentally obtained tibio-femoral contacts

The purpose of this study is to investigate the effect of anterior portion of anterior cruciate ligament, posterior cruciate ligament, anterior and deep portions of medial collateral ligament and the tibio-femoral articular contacts on passive knee motion. A well-accepted reference model for a normal tibio-femoral joint is reconstructed from the literature. The proposed three-dimensional dynamic tibio-femoral model includes the isometric fascicles, ligament bundles and irregularly shaped medial-lateral contact surfaces. With the approach we aim to analyze bone shape and ligament related abnormalities of knee kinematics. The rotations, translations and the contact forces during passive knee flexion were compared against a reference model and the results were found in close accordance. This study demonstrated that isometric ligament bundles play an important role in understanding the femur shape from contact points on tibia. Femoral condyles are not necessarily spherical. The surgical treatments should consider both ligament bundle lengths and contact surface geometries to achieve a problem free knee kinematics after a knee surgery. (C) 2007 Elsevier Ltd. All rights reserved

Discrimination of abnormal gait parameters due to increased femoral anteversion from other effects in cerebral palsy

The effects of increased femoral anteversion (IFA) on gait pattern have a complex relationship with other orthopaedic and neurological abnormalities of cerebral palsy (CP). The aim of this study was to differentiate the effects of IFA from other factors in CP. The four groups in this study included: 15 typically developing children (Group: TDC) (age: 9.7 +/- 0.5); 14 TDC with IFA (7.5 +/- 1.7) (Group: TDC-IFA); 8 CP participants with IFA (age: 6.3 +/- 1.7) (Group: CP IFA); and 10 CP participants with nearly normal femoral anteversion (age: 10.3 +/- 4.7) (Group: CP-NFA). Altered peak knee-extension angle and stance-time, increased internal hip-rotation, internal foot-progression (p <= 0.05) were influenced by IFA in both groups of CP-NFA and TDC-IFA. For the TDC groups; pelvic-rotation increased and peak knee and hip-extension, knee flexion-moment, peak knee-power generation in late-stance decreased among children with IFA (p <= 0.05). For CP children; anterior pelvic-tilt, hip-flexion and peak knee-extension, hip power-absorbsion and generation, and peak knee power-absorsion (K3) increased and peak knee-flexion was delayed by IFA (p <= 0.05)

Effects of Increased Femoral Anterversion on Gait in Children with Cerebral Palsy

Objective: The aim of this study is to identify the gait deviations due to increased femoral anteversion and to distinguish these deviations from those which are commonly seen in children with spastic diplegic cerebral palsy (SD)