Pelvic Tilt Angle Differences Between Symptom-Free Young Subjects and Elderly Patients Scheduled for THA: The Rationale for Tilt-Adjusted Acetabular Cup Implantation

Background: The question whether Pelvic Tilt (PT) angles measured in the supine position are adequate for the alignment of the acetabular cup without an adjustment for anatomical differences between patients is of clinical importance. The aim of this work was to test for factors that can significantly affect PT angles. Methods: In the present retrospective cohort comparison, the PT angles of 12 Symptom-Free Young Subjects (SFYS) and 45 patients scheduled for Total Hip Arthroplasty (THA) were compared. The data was collected during two studies with the use of a novel smartphone-based navigated ultrasound measurement system. Multi-factorial analysis of variance was run to determine which factors significantly affect PT. Results: Body position (F= 126.65; P< 0.001) and group (SFYS vs. THA patients) (F= 17.52; P< 0.001) had significant main effects on PT. There was also a significant interaction between body position and group (F= 25.59; P< 0.001). The mean PT increased by 8.1° from an interiorly to a neutral tilted position (P< 0.001) and 21.4° from a neutral to a posteriorly tilted position (P< 0.001) with the transition from the supine into the upright position for the SFYS and THA patients, respectively. Conclusion: In both groups, PT changed significantly with a transition from the supine to the upright position. A position-dependent mean PT increase in the patient group showed that acetabular cup alignment based on PT in the supine position is not reliable without taking into consideration the inclination of the pelvis in standing position. This may lead to instability and dislocations.

Sex-Related Differences in Scapular Kinematics During Elevation of the Arm in Asymptomatic Children and Adults

Recently, it has been suggested that sex may influence scapular kinematics. A more comprehensive analysis of the scapular kinematics in children and adults, including sex as a factor, will help to understand if differences between sexes are present since childhood. The purpose of this study was to compare scapular kinematics between sex in children and adults during elevation of the arm. One-hundred and sixteen asymptomatic adults (58 men and 58 women) and 53 children (28 boys and 25 girls) participated in the study. Three-dimensional scapular kinematics during elevation of the arm were obtained using an electromagnetic tracking device. Women had a more upwardly rotated scapula in the nondominant side (P < .05), with large effects and a more anteriorly tilted position at 60°, 90°, and 120° of arm elevation in the dominant side, and at 90° and 120° in the nondominant side (P < .05) with moderate effects when compared with men. Differences between sexes were not found in the children (P > .05). In conclusion, sex seems to influence scapular kinematics in adulthood, but not in childhood.

Slant board immobilisation of head-and-neck radiotherapy patients who cannot tolerate a flat position

PurposePatients treated with intensity-modulated radiation therapy (IMRT) for head-and-neck cancer are often positioned supine on a carbon fibre board to which a thermoplastic mask is attached to immobilise the head and shoulders. For patients unable to tolerate a supine position, we developed a tilting board that accommodates a full-scale head-and-shoulder mask.Materials and methodsPhantom measurements were obtained to confirm the dosimetric accuracy of our treatment planning system when using this board. A patient was simulated in the flat and tilted positions on the board. The two corresponding treatment plans were evaluated by comparing the target coverage and doses with organs at risk. The patient’s intra-fraction motion was quantified during his tilted treatments.ResultsPhantom measurements confirmed the accuracy of the dosimetric calculations. The tilted plan met dosimetric standards for clinical acceptability. The intra-fraction motion of the patient in the tilted position was >3 mm in any direction.ConclusionsThe tilting board met clinical requirements for IMRT planning and delivery. Full-scale head-and-shoulder immobilisation was achieved in a more tolerable tilted position.

Does venous insufficiency impair the exercise-induced rise in arterial leg blood flow?

Objectives It has been shown that the leg muscle pump increases the immediate rise in arterial leg blood flow during upright exercise in healthy subjects. The present study is the first to investigate the muscle pump effect in exercise hyperaemia in patients with venous insufficiency, who should be lacking an optimally functioning muscle pump. Methods Any muscle pump effect is more pronounced in an upright position because of gravitation. The exercise-induced rise in femoral artery flow (FF) (ultrasound Doppler) was thus compared in the supine and 30° head-up tilted position in 10 patients. Results Neither the transient nor the steady-state rise in FF showed any difference between positions. This is in contrast to the previous findings in healthy subjects, where the transient rise in FF was larger in the tilted position. Conclusion The muscle pump effect in exercise hyperaemia seems to be reduced or lacking in these patients.