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Biomedical subjects

J M Kabo

Publications and source records attributed to J M Kabo.

62 records · Page 4Linked to original sources
PubMed1984

Flow characteristics of acrylic bone cements.

Flow properties of Simplex, Zimmer Regular, Zimmer LVC, and Sulfix bone cements were measured as functions of time between two and five minutes after mixing. The mass flowrates measured for Zimmer Regular and Simplex were quite similar in the temperature range of 20.0 degrees -23.3 degrees. At 18.3 degrees Simplex had approximately double the flowrate of Zimmer Regular two minutes after mixing. The flowrate for LVC was approximately four times that measured for Zimmer Regular at 20.0 degrees. Sulfix displayed the greatest sensitivity of flowrate with temperature; at 18.3 degrees its flow characteristics were similar to those of LVC, and at 23.3 degrees it behaved more like Simplex and Zimmer Regular. All cements demonstrated substantial relative increases in flowrates with only slight increases in pressure; Sulfix was the most pressure sensitive. Set times for Zimmer, LVC, and Sulfix were virtually identical, ranging from a mean of 11 minutes (at 18.3 degrees) to 7.5 minutes (at 23.3 degrees). Simplex had considerably longer set times, averaging 15.8 minutes (at 18.3 degrees) and 9.4 minutes (at 23.3 degrees). Although Simplex demonstrated the greatest sensitivity of set time with temperature (almost double that measured for the other 3 cements), it did not show the greatest sensitivity of flowrate with temperature.

Bone Cements↗
PubMed1983

Response of a human head-neck model to transient saggital plane loading.

A reproducible, synthetic replica of the human head and neck system utilizing a water-filled cadaver skull mounted on fiberglass-reinforced resin vertebrae and supported by passive silicone rubber muscle and ligament elements has been constructed. Contact force, head accelerations, disk pressures and intracranial pressure responses to conditions of transient saggital plane pendulum loading have been ascertained. Front and rear head impacts as well as excitation of the entire system through its rigid base were effected. Input energies ranging from 0.0089 N m to 4.63 N m were employed resulting in head accelerations up to 180 g.

Acceleration↗
PubMed1983

In-vitro head and neck response to impact.

Two unembalmed and one embalmed human cadaveric head-neck systems were instrumented and subjected to central forehead impact of ballistically suspended 3.07-kg aluminum shell at velocities ranging from 50 to 345 cm/s. Occipital skull accelerations and disk pressures were measured by transducers, while the deformation of the system was determined by framing camera data. The results were found to be in accord with those from corresponding tests in artificial head-neck replica. Initial and terminal X-ray examination of the structure revealed no evidence of either skull or vertebral fractures.

Acceleration↗
PubMed1983

Frictional torque in surface and conventional hip replacement.

UNLABELLED: The frictional torque of the Trapezoidal-28 total hip replacement and the Tharies SR-3 and SR-5 surface replacements were measured in the University of California at Los Angeles hip-joint simulator in calf serum. Loads of as much as 890 newtons were applied while the femoral component oscillated through a 60-degree arc at forty cycles per minute. Frictional torque, as measured by a ring transducer at a fixed distance from the center of rotation, was seen to diminish as the thickness of the polyethylene increased and was found to be relatively proportional to the diameter of the femoral component. The torques measured in this study were found to be twenty to 100 times smaller than the static torques to failure for acetabular fixation that have been reported in the literature. Finally, no permanent deformation of the thin acetabular shells attributable to the cementing process was apparent when the recommended technique of surgical insertion was utilized. CLINICAL RELEVANCE: Surface replacement components have been shown to generate greater frictional torques at the acetabular bone-cement interface than do smaller-diameter conventional hip replacements. This indicates that the local mechanical-loading conditions of the hip joint are not the same for both types of replacements, and this should be considered when selecting the type of arthroplasty for an individual patient.

Biomechanical Phenomena↗
PubMedDate not supplied

Performance of baseball headgear.

An experiment was conducted to ascertain the effectiveness of commercially available baseball headgear in a simulated environment where the head of the batter is struck. Using a compressed air cannon, baseballs were fired at an instrumented headform at frontal and temporal locations with and without a helmet. Striking velocities ranged from 50 to 120 mph and rebound velocities were 1/3 to 1/2 of that of the initial speed. Additional impact tests were conducted on equivalent flat helmet sections backed by a rigid steel plate, the results of which seemed to indicate that the materials and configurations currently employed do little to dissipate the energy of the striker. Head accelerations in excess of 1,000 G were measured, but quantitative injury potential could not be assessed since no applicable tolerances currently exist. We concluded that the incorporation of additional external padding on the plastic shell of the helmet and/or modifications of the suspension would significantly improve the energy absorption capabilities of the helmet and further minimize the possibility of head trauma.

Athletic Injuries↗
PubMedDate not supplied

Ankle sprain prophylaxis: an analysis of the stabilizing effects of braces and tape.

Five cadaveric ankles were used to determine the effects of prophylactic bracing and tape on resisting an inversion moment applied to the ankle. The ankles were tested in neutral flexion and 30 degrees of plantar flexion and with both low- and high-top shoes. Eight different strap-on braces were studied. High-top sneakers significantly increased the passive resistance to inversion afforded by all braces and tape. Many of the braces functioned to resist inversion at a level that was comparable with or exceeded the capability of freshly applied tape. This finding was independent of the type of footwear. Braces that were not as effective as freshly applied tape nevertheless retained the advantage over tape in that they could be easily readjusted and their effectiveness restored, whereas the quality of the support provided with tape deteriorated with usage.

Adult↗