Biomedical subjects

D A Meglan

Publications and source records attributed to D A Meglan.

3 recordsLinked to original sources

PubMed1996

The teleos virtual environment toolkit for simulation-based surgical education.

In the past, surgical simulations have largely been created through the development of dedicated applications that require considerable programming and computer graphics skills. Advances in simulation-based surgical education have been limited by this dependence on computer graphics programming expertise. To lower barriers to the adoption of simulation-based training, we are developing tools based on Teleos, software technology that allows a wide variety of medical content developers to author surgical training simulations without programming.

Computer Graphics↗

PubMed1987

Femoral cement removal in revision total hip arthroplasty. A biomechanical analysis.

A technique of femoral cement removal in revision total hip arthroplasty is described and biomechanically evaluated. Two 9-mm holes are drilled anteriorly through the proximal femoral cortex before cement is removed. These holes permit direct visualization of the medullary canal and help to prevent eccentric reaming or inadvertent perforation with the power drill. They also provide portals for enhanced irrigation, illumination, and cement removal. For assessment of the effect of cortical perforations on bone strength, 12 cadaveric femurs containing cemented prosthetic stems were analyzed. The femurs were stressed at various loads on the Instron Materials Testing Machine (Instro Engineering Corporation, Kenton, MA) under conditions simulating single-limb stance. The stress concentrations were significantly higher about laterally drilled holes than about those located anteriorly. When loaded to failure, all fractures occurred at or below the prosthetic stem tip. No fractures occurred in the proximally placed drill holes. A finite element model showed that two holes kept at least two hole diameters apart did not cause cumulative stress concentration.

Biomechanical Phenomena↗

PubMedDate not supplied

Comparison of intersegmental tibiofemoral joint forces and muscle activity during various closed kinetic chain exercises.

The purpose of this study was to analyze intersegmental forces at the tibiofemoral joint and muscle activity during three commonly prescribed closed kinetic chain exercises: the power squat, the front squat, and the lunge. Subjects with anterior cruciate ligament-intact knees performed repetitions of each of the three exercises using a 223-N (50-pound) barbell. The results showed that the mean tibiofemoral shear force was posterior (tibial force on femur) throughout the cycle of all three exercises. The magnitude of the posterior shear forces increased with knee flexion during the descent phase of each exercise. Joint compression forces remained constant throughout the descent and ascent phases of the power squat and the front squat. A net offset in extension for the moment about the knee was present for all three exercises. Increased quadriceps muscle activity and the decreased hamstring muscle activity are required to perform the lunge as compared with the power squat and the front squat. A posterior tibiofemoral shear force throughout the entire cycle of all three exercises in these subjects with anterior cruciate ligament-intact knees indicates that the potential loading on the injured or reconstructed anterior cruciate ligament is not significant. The magnitude of the posterior tibiofemoral shear force is not likely to be detrimental to the injured or reconstructed posterior cruciate ligament. These conclusions assume that the resultant anteroposterior shear force corresponds to the anterior and posterior cruciate ligament forces.

Adult↗