Radiation exposure during skeletal traction treatment of pediatric femoral fractures.

Radiation-exposure data during femoral fracture management has not been previously reported. We report a retrospective analysis of radiation exposure in 45 patients aged 5-12 years (average, 8.3) with isolated femoral shaft fractures treated by 90/90 degrees femoral skeletal traction. Group I had 32 patients aged 5-9 years (average, 7.3), and group II had 13 patients of an average age of 10.7 years. Total average radiation dose before casting was 0.699 rads and was independent of age and gender. In addition to potential complications of tractions and increased hospital stay with attendant fiscal and psychosocial burdens, radiation exposure with this type of management, in this series, was significant.

The Frank Stinchfield Award. Pulmonary fat embolism in revision hip arthroplasty.

Unilateral cemented hip hemiarthroplasty was done on 16 dogs who subsequently had revision arthroplasty and who were divided into 1 control and 3 experimental groups: The first group had cement extraction using osteotomes; the second, using a high speed burr; the third, an ultrasonic tool. Hemodynamic and transesophageal echocardiographic monitoring were done. Postmortem pulmonary specimens were examined for differences in the quantity of fat emboli. There was a significant increase in emboli with the ultrasonic tool as compared with osteotomes and high speed burr. There was no significant difference in emboli between the osteotomes and high speed burr. Fat emboli syndrome is related to mechanical compression of the femoral canal. The ultrasonic instrument was unique in its tendency to cause large embolic showers, especially during extraction of the distal cement plug. In these young dogs, minimal hemodynamic changes and no cardiac dysrhythmias occurred, which in part may be attributed to their good health. These changes may remain subclinical for patients with good cardiorespiratory reserve, or may become life threatening for those with poor reserve. By outlining the mechanisms of fat embolism in revision total hip arthroplasty, it may be possible to decrease future morbidity, especially in patients who frequently have cardiopulmonary disease.

Intraoperative somatosensory evoked potential monitoring of the sciatic nerve: an animal model.

Sciatic, peroneal, and tibial nerves were isolated in 18 hind limbs in 10 adult mongrel cats. A pair of needle electrodes was used to stimulate both divisions of the sciatic nerve individually at the level of the popliteal fossa. The sciatic nerve was injured by complete or partial transection, crush, and controlled compression. Motor function was correlated with intraoperative cortical somatosensory evoked potential and spinal somatosensory evoked potential tracings. We observed that significant changes in the waveforms of cortical somatosensory evoked potential and spinal somatosensory evoked potential tracings immediately precede postoperative peripheral nerve deficits, and that loss of motor function may be avoided by immediate response to significant spinal somatosensory evoked potential and cortical somatosensory evoked potential waveform changes. A complete motor palsy can be created in one division of the sciatic nerve while normal tracings are being obtained in the other division of the nerve. Stimulating both divisions may result in a spinal somatosensory-evoked potential/cortical somatosensory evoked potential tracing that masks the deficit that is present in only one nerve division.

Effects of dynamization after interlocking tibial nailing: an experimental study in dogs.

Dynamization of statically locked tibial nails was studied in a canine model. Reamed static interlocking nails were inserted in 16 canine tibiae with unstable osteotomies. At 8 weeks, half were dynamized. At 20 weeks, the tibiae were harvested and studied radiographically, biomechanically, and histologically. Apparent clinical union was present in all tibiae. Complete radiographic bony union was achieved in 13 of 16, with residual radiolucent lines in two tibiae in the static and one in the dynamic group. Biomechanically, dynamization improved stiffness at the fracture site. Histological patterns were similar, but there were trends toward a denser trabecular callus pattern in the dynamized group. The results of this animal study indicate that although dynamization may have a beneficial effect on the quality of early bony healing, static interlocking does not decrease the rate of bony union.