Biomedical subjects

E Biden

Publications and source records attributed to E Biden.

3 recordsLinked to original sources

PubMed1990

Kinematic variability and relationships characterizing the development of walking.

The purposes of this study were: (1) to determine the pattern of variability and relationships in joint kinematics characterizing the development of walking and (2) to determine whether controlling for postural stability in new walkers results in less variability. The variability and relationships among hip, knee, and ankle motions were measured during 10 gait cycles of new walkers, supported new walkers, two-year-olds and seven-year-olds. Fourier series were generated for each joint motion and standard deviations were compared across groups. An age-related decline in variability was evident in select portions of the cycle. Stance and swing phase duration correlated with cycle duration for all ages. Postural support did not lessen variability in joint rotations for new walkers. Cross-correlations for hip-knee, knee-ankle, and hip-knee rotations were strong across all groups. These results suggest that a coordinative structure for walking produces strong intralimb coupling early in development, despite variability in select portions of joint motions.

Child↗

PubMed1989

The geometry of the knee in the sagittal plane.

A geometric model of the tibio-femoral joint in the sagittal plane has been developed which demonstrates the relationship between the geometry of the cruciate ligaments and the geometry of the articular surfaces. The cruciate ligaments are represented as two inextensible fibres which, with the femur and the tibia, are analysed as a crossed four-bar linkage. The directions of the ligaments at each position of flexion are calculated. The instant centre, where the flexion axis crosses the parasagittal plane through the joint, lies at the intersection of the cruciates. It moves relative to each of the bones during flexion and extension. The successive positions of the flexion axis relative to a fixed femur and to a fixed tibia are deduced. The shapes of articular surfaces which would allow the bones to flex and extend while maintaining the ligaments each at constant length are calculated and are found to agree closely with the shapes of the natural articular surfaces. The calculated movements of the contact point between the femur and the tibia during flexion also agree well with measurements made on cadaver specimens. The outcome is a geometric simulation of the tibio-femoral joint in the sagittal plane which illustrates the central role played by the cruciate ligaments in the kinematics of the knee and which can be used for the analysis of ligament and contact forces.

Biomechanical Phenomena↗

PubMedDate not supplied

Soft tissue fixation to bone.

This experiment was designed to compare the immediate fixation strengths of various methods of soft tissue fixation techniques. The fixation techniques tested were the barbed staple, stone staple, suture techniques, screw with spiked plastic washer, and the screw with spiked soft tissue plate. Cadaveric soft tissue specimens were classified into three distinct morphologic types: capsular, tendinous, and extensor mechanism tissue. Each specimen was fixed to bone by one of the fixation techniques. The specimens were loaded in a cyclical fashion until fixation failure occurred. One hundred thirty-seven trials were performed. The screws with the spiked plastic washer and soft tissue plate proved superior overall for all three tissue types. The stone staple was the poorest technique tested. Therefore, if cyclic loading or tension is anticipated at the fixation site, the fixation technique of choice would be the screw with spiked plastic washer or soft tissue fixation plate.

Bone Screws↗