ObjectiveTo evaluate the accuracy of using smartphone to measure the angle of acetabular component in total hip arthroplasty (THA). MethodsBetween June 2012 and September 2015, the acetabular abduction and anteversion angles were measured in 50 patients undergoing THA. There were 24 males and 26 females, aged 37 to 83 years (mean, 71 years). The left hip was involved in 22 cases and the right hip in 28 cases. Of 50 patients, 34 suffered from fracture of the femoral neck, and 16 suffered from avascular necrosis of the femoral head. Acetabular dysplasia was excluded in all cases. A smartphone was used to measure the acetabular abduction and anteversion angles during operation; standard Picture Archiving and Communication Systems (PACS) was used to measured the acetabular abduction and anteversion angles on the X-ray film at 1 week after operation. It was defined as positive that the component angle values by PACS measurement were greater than those by the smartphone measurement, whereas as negative. The two measurement methods were compared, and intra-observer variability was assessed by analyzing the intraclass correlation coefficient (ICC), the Mann-Whitney U-test was used to analyze difference. ResultsThe ICC was 0.84 in the acetabular component angles by smartphone and PACS measurement methods. The acetabular component abduction angle was (44.02±1.33)° and the anteversion angle was (17.62±2.20)° by smartphone measurement. The acetabular component abduction angle was (44.74±4.05)° and the anteversion angle was (17.22±5.57)° by PACS measurement. There was no significant difference between two measurement methods (Z=-1.977, P=0.482; Z=-0.368, P=0.713). The acetabular component angle was in the safe zone in 44 cases; and the acetabular component anteversion angle was beyond safe range of 1 to 5°, and the abduction angle was beyond safe range of 1 to 3° in 6 cases. Intra-measurement variability was -21 to +10° for the anteversion angle and -10 to + 9° for the abduction angle, indicating that the acetabular component anteversion angle by smartphone measurement was greater than that by the PACS measurement, and the abduction angle was less than that by PACS measurement. ConclusionSmartphone is a convenient tool to measure the acetabular component angle in THA.
ObjectivesTo investigate the influence of the abduction angle of the upper extremities on the image quality of non-enhanced CT scan and clinical value of the patients who cannot lift with double upper limbs by vehicle accident.Methods60 patients with double upper limbs that could not lift by vehicle accidents were required to receive liver non-enhanced CT scan, the patients were divided into 3 groups according to the abduction angle (group A, B, C), 20 cases in each group, another 20 cases with standard pose as the control group (group D). The CT value and standard deviation of the liver region of interest, the erector and the background air were measured, and the contrast to noise ratio of liver images, image noise value were calculated, together with the assessment of image quality and statistic analysis.ResultsThe liver non-enhanced CT scan were completed successfully. The image quality of group D was significantly better than A, B, C (Z=–10.753, P<0.05;Z=–11.645, P<0.05;Z=–12.281, P<0.05), respectively. Group C was better than A and B (Z=–8.502, P<0.05;Z=–4.068, P<0.05), respectively. Group B was better than A (Z=–5.885, P<0.05). The CNR of the four groups of images increased gradually, group A (0.09±0.77), group B (1.56±0.83), group C (2.51±0.87), group D (2.59±0.97), respectively. There were significant differences between four groups (F=36.323, P<0.05). The image noise decreased systematically, group A (14.84±2.94), group B (13.04±1.59), group C (11.60±1.72), group D (10.44±1.13), respectively. There were significant differences between four groups (H=426.755, P<0.05).ConclusionOn the premise of safety inspection, with the enlargement of angle of the upper limbs of patients who cannot lift with double upper limbs by vehicle accidents, the image noise decreased and image quality is improved with the increase of signal noise ratio.