There is debate about whether distinct designs of femoral components for men and women are needed based on morphologic and size differences between genders. We asked whether anthropomorphic differences exist between the distal femoral dimensions in women and men. We measured the distal femora of 100 women and 100 men intraoperatively after preparation for prosthetic implantation. The measured dimensions included the anteroposterior height from the posterior edge of the medial femoral condyle to the flush anterior cut, the mediolateral width at the transepicondylar axis, the anterior and posterior edges of the anterior chamfer, and the medial and lateral trochlear flanges. These measurements were compared between genders using independent-samples t test. The aspect ratio (a measure of the shape of the distal femur), the ratio between the anteroposterior and mediolateral dimensions, was calculated for men and women to determine whether there is a shape difference between genders. The mean aspect ratio was larger for women than for men (0.84 [range, 0.57-1.03] versus 0.81 [range, 0.066-1.34], respectively). The standard deviation and range of each measurement of size and morphology suggest variability not only between genders but also within genders. Whether the aspect ratios and variations will reflect clinically important differences in outcomes after TKA with available prostheses will require additional study.

Young children rely heavily on vision for postural control during the transition to walking. Although by 10 years of age, children have automatic postural responses similar to adults, it is not clear when the integration of sensory inputs becomes fully developed. The purpose of this study was to examine this transition in the sensory integration process in children aged 7-12 years. Healthy children and adults stood on a fixed or sway-referenced support surface while viewing full-field optic flow scenes that moved sinusoidally (0.1 and 0.25 Hz) in an anterior-posterior direction. Center of pressure was recorded, and measures of sway amplitude and phase were calculated at each stimulus frequency. Children and adults had significant postural responses during approximately two-thirds of the trials. In adults, there was a 90% decrease in sway on the fixed surface compared with the sway-referenced surface, but only a 50% decrease in children. The phase between the optic flow stimulus and postural response in children led that of adults by 52 degrees at 0.1 Hz and by 15 degrees at 0.25 Hz. Adults and children aged 7-12 years have similar ability to use dynamic visual cues for postural control. However, 7-12-year-old children do not utilize somatosensory cues to stabilize posture to the same extent as adults when visual and somatosensory cues are conflicting.

We show evidence of the viability of delivering auditory stimulation during sleep, at home, to enhance slow wave activity. The system ensures the stimulation delivery to be at the right time during sleep without causing disturbance.

On the basis of our experience in this relatively small series with short-term follow-up, the results of total knee arthroplasty do not seem to be compromised after revision of the failed patellofemoral replacement.

Changes in posture can affect the resting length of the diaphragm, requiring alterations in the activity of both the abdominal muscles and the diaphragm to maintain stable ventilation. To determine the role of the vestibular system in regulating respiratory muscle discharges during postural changes, spontaneous diaphragm and rectus abdominis activity and modulation of the firing of these muscles during nose-up and ear-down tilt were compared before and after removal of labyrinthine inputs in awake cats. In vestibular-intact animals, nose-up and ear-down tilts from the prone position altered rectus abdominis firing, whereas the effects of body rotation on diaphragm activity were not statistically significant. After peripheral vestibular lesions, spontaneous diaphragm and rectus abdominis discharges increased significantly (by approximately 170%), and augmentation of rectus abdominis activity during nose-up body rotation was diminished. However, spontaneous muscle activity and responses to tilt began to recover after a few days after the lesions, presumably because of plasticity in the central vestibular system. These data suggest that the vestibular system provides tonic inhibitory influences on rectus abdominis and the diaphragm and in addition contributes to eliciting increases in abdominal muscle activity during some changes in body orientation.