Xie Kunjie, Lei Wei, Yan Yabo
Department of Orthopedics, Xijing Hospital, Air Force Military Medical University, Xi'an, China.
BMC Musculoskelet Disord. 2025 Jul 28;26(1):718. doi: 10.1186/s12891-025-08904-5.
In regions lacking professional digital imaging equipment, parents sometimes use smartphones to take photos of pelvic X-ray films and transmit them to clinicians via a messaging application for consultation. However, the accuracy of measuring parameters through photos is unknown. Certain factors that affect photograph quality may lead to deviations in pelvic radiographic measurements. This study investigates the impact of photography angles on measurements of the Acetabular Index (AI) and Center-edge Angle (CEA).
We collected pelvic radiographs from 50 patients who were suspected of having DDH. We constructed an experimental setup incorporating a tripod and a film viewer, and captured 850 photos across a range of smartphone tilt or rotation angles from - 20° to 20°, with a gradient of 5[Formula: see text]. Photos with zero-degree tilt and rotation were considered standard. Two researchers independently measure the AI and CEA. A one-way ANOVA and Dunnett T3 post-test were used to compare the relationship between photography angle and parameter variances. Simple linear regression was used to quantify the relationship between the two. An independent samples t-test was performed to compare differences in hip parameter changes between DDH and normal individuals.
The measurements of the AI and CEA on the photographs captured by smartphones show excellent consistency with those on the radiographic films (ICC ranges from 0.940 to 0.998). The smartphone's high-angle shot, right rotation, and left rotation will cause an increase in bilateral CEA, right AI, and left AI, respectively. Other changes will lead to a decrease in CEA or AI. Linear regression analysis revealed that the right AI increased by approximately 0.09 ° for each 1° increase in right rotation. Conversely, it decreased by 0.09°, 0.06°, or 0.09° for each 1° increase in high-angle shot, low-angle shot, or left rotation, respectively. The right CEA increased by about 0.21° for each 1° in photography tilt and decreased by about 0.08° or 0.13° for each 1° in left or right rotation. The left hip also exhibits a similar pattern. The change in AI caused by smartphone tilt is greater in patients with DDH than in normal individuals.
Capturing radiographic photos with a smartphone can serve as a potential alternative for the follow-up and evaluation of DDH. Photography angles can directly affect the measurement of hip parameters. Clinicians must assess the quality of the photographs before providing suggestions. Quantifying the relationship between photography angles and hip parameter variance can assist clinicians in making more comprehensive and accurate assessments in DDH.
在缺乏专业数字成像设备的地区，家长有时会用智能手机拍摄骨盆X光片，并通过即时通讯应用程序将其发送给临床医生进行咨询。然而，通过照片测量参数的准确性尚不清楚。某些影响照片质量的因素可能导致骨盆影像学测量出现偏差。本研究调查摄影角度对髋臼指数（AI）和中心边缘角（CEA）测量的影响。
我们收集了50例疑似患有发育性髋关节发育不良（DDH）患者的骨盆X光片。我们构建了一个包含三脚架和胶片观察器的实验装置，并在智能手机倾斜或旋转角度从-20°到20°、梯度为5°的范围内拍摄了850张照片。倾斜和旋转角度为零度的照片被视为标准照片。两名研究人员独立测量AI和CEA。采用单因素方差分析和Dunnett T3事后检验来比较摄影角度与参数差异之间的关系。使用简单线性回归来量化两者之间的关系。进行独立样本t检验以比较DDH患者和正常个体髋关节参数变化的差异。
智能手机拍摄的照片上AI和CEA的测量结果与X光片上的测量结果具有极好的一致性（组内相关系数范围为0.940至0.998）。智能手机的高角度拍摄、向右旋转和向左旋转将分别导致双侧CEA、右侧AI和左侧AI增加。其他变化将导致CEA或AI降低。线性回归分析显示，向右旋转每增加1°，右侧AI增加约0.09°。相反，高角度拍摄、低角度拍摄或向左旋转每增加1°，右侧AI分别降低0.09°、0.06°或0.09°。摄影倾斜每增加1°，右侧CEA增加约0.21°，向左或向右旋转每增加1°，右侧CEA分别降低约0.08°或0.13°。左侧髋关节也呈现类似模式。智能手机倾斜导致的AI变化在DDH患者中比在正常个体中更大。
用智能手机拍摄X光照片可作为DDH随访和评估的一种潜在替代方法。摄影角度可直接影响髋关节参数的测量。临床医生在提供建议前必须评估照片质量。量化摄影角度与髋关节参数差异之间的关系可帮助临床医生在DDH中进行更全面准确的评估。
