OBJECTIVES Fractures of the proximal femur are a common clinical problem, and a number of orthopaedic devices are available for the treatment of such fractures. The objective of this study was to assess the rotational stability, a common failure predictor, of three different rotational control design philosophies: a screw, a helical blade and a deployable crucifix. METHODS Devices were compar...

Both medial and anterolateral plate applications have been described for the treatment of distal tibia fractures, each with distinct advantages and disadvantages. The objective of this study was to compare the biomechanical properties of medial and anterolateral plating constructs used to stabilize simulated varus and valgus fracture patterns of the distal tibia. In 16 synthetic tibia models, a...

Torsional tension in DNA may be both a prerequisite for the efficient initiation of transcription and a consequence of the transcription process itself with the generation of positive torsional tension in front of the RNA polymerase and negative torsional tension behind it. To examine torsional tension in specific regions of genomic DNA in vivo, we developed an assay using photoactivated psoral...

Nickel-titanium engine-driven rotary instruments are used increasingly in endodontic practice. One frequently mentioned problem is fracture of an instrument in the root canal. Very few studies have been conducted on torsional characteristics of these instruments, and none has been done under dynamic conditions. The purposes of this study were to measure the torque generated and the apical force...

We report the measurement of two new perpendicular (D2O)3 torsional bands by terahertz laser vibration–rotation–tunneling ~VRT! spectroscopy of a planar pulsed supersonic expansion. The first ~28.0 cm) band corresponds to the k562 ←0 transition, and is the lowest frequency vibrational spectrum observed for a water cluster. The second ~81.8 cm) band originates in the first excited torsional stat...

The mechanical response of a metal–matrix composite to dynamic shearing deformations has been measured, using a new design of the thin-walled tubular specimen for the torsional Kolsky bar experiment that allows working with these difficult-to-machine materials. The advantages of using the new specimen design are as follows: (i) the thickness of the thin wall along the axial direction is very un...

BACKGROUND The purpose of this study was to evaluate the biomechanical advantages of medial support screws (MSSs) in the locking proximal humeral plate for treating proximal humerus fractures. METHODS Thirty synthetic left humeri were randomly divided into 3 subgroups to establish two-part surgical neck fracture models of proximal humerus. All fractures were fixed with a locking proximal hume...

To aim of this study was to investigate the bone response to calcium phosphate (Ca-P) plasma-spray and radiofrequency magnetron sputter-coated implants with comparable roughness. Therefore, tapered conical screw designed implants were installed in the trabecular bone of the femurs of nine goats. They were provided with two types of coatings, a plasma-spray dual coating of fluorapatite and hydro...

The purpose of this study was to evaluate the effects of isolated alterations in mineral content on mouse bone torsional properties. The femora and tibiae from 25 eight-week-old male A/J strain mice were divided into five groups and selectively decalcified from 5% to 20%. The right femora were then tested to failure in torsion while the tibiae were ashed to determine final mineral content of th...