PubMed · 3827475
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H Okumura. 1986-03-01. [Total hip replacement].. https://pubmed.ncbi.nlm.nih.gov/3827475/
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The lumbar lordosis and pelvic tilt of twenty male subjects were measured in standing and in three different sitting postures with the trunk-thigh angles of 120 (sitting A), 90 (sitting B), and 60 (sitting C) degs and the knee angle was constant at 90 deg. Ten more male subjects participated in the supplemental study, in which additional condition of the knee angle was employed in postures of the trunk-thigh angles of 90 and 60 degs. Some joint mobilities were also measured to investigate the relations of the mobilities to lumbar lordosis and pelvic tilt. The lumbar curve decreased and the pelvis rotated rearward significantly as the trunk-thigh angle and the knee flexion decreased. The great alteration of the lumbar curve was observed between standing and sitting A, which was much different from the results of Keegan (1953) studied in the subjects of lateral recumbent position. There was a high correlation coefficient between the lumbar curve and the pelvic tilt (r = 0.909), so that the relations of the pelvic tilt to the joint mobilities were investigated. When the knee angle was constant, the pelvic tilt is related significantly to the hamstrings between standing and sitting A and to the gluteus maximus between sitting A and sitting C. However, at different sitting postures with the trunk-thigh angles of 90 and 60 degs involving different knee flexions, hamstrings added to gluteal muscles affected significantly lumbar curve and pelvic tilting.(ABSTRACT TRUNCATED AT 250 WORDS)
PURPOSE: Quantitative assessment of the accuracy of field alignment in a homogeneous group of patients with difficult positioning (postoperative irradiation after total hip replacement). METHODS AND MATERIALS: In 95 patients linear and rotational discrepancies were measured between the simulation and first check film and between five consecutive verification films. RESULTS: For the total group of patients, all deviations were normally distributed with mean values of approximately zero and standard deviations of 4.0-8.0 mm (linear discrepancies) and 3.5-5 degrees (rotational discrepancies). Deviations were similar for the transition from simulator to the treatment machine and for subsequent treatment delivery, with 50% and 95% of absolute differences being less than 5 mm and 15 mm, respectively. CONCLUSIONS: Our analysis indicates that statistical fluctuations are considerably more important than errors introduced at start of treatment. Therefore, a first check film seems to be inadequate to predict the expected inaccuracies for the whole course of treatment. In addition, our results should help to prescribe appropriate safety margins for patients with difficult positioning.