Canine hip dysplasia (CHD) is a multifactorial disease affecting large breed dogs with associated joint laxity and incongruity that predisposes them to osteoarthritis. The purpose of the study is to objectively compare the conformation of normal and near-normal coxofemoral joints (CFJS) in Labrador Retrievers versus German Shepherds on the extended ventrodorsal radiograph. Investigated groups were categorized as normal and near-normal CFJS according to the morphometric criteria established by the FCI scoring system. Center-edge (CE) angle, Norberg angle (NA), indices of dorsal AFH coverage width and area, acetabular slope (AS) angle, and inclination angle were determined for each group. CE angle and AS angle were modified from previously described human techniques. The width and area of dorsal AFH coverage were standardized by the corresponding femoral head diameter and area. Variables were compared between groups using an unpaired, two-tailed t-test. A Spearman correlation coefficient determined the relationship between selected variables. In Labradors, CE angle (lateral coverage) and dorsal AFH coverage area index (dorsal coverage) were greater in normal versus near-normal CFJS. In German Shepherds, lateral AFH coverage (CE angle and NA) was greater in normal versus near-normal hip joints; whereas, dorsal AFH coverage did not differ between the two groups. Lateral AFH coverage was greater in normal versus near-normal CFJS of both breeds. In Labradors, the inclination angle was greater in near-normal versus normal CFJS. Normal CFJS of Labradors revealed greater lateral and dorsal AFH coverages compared to German Shepherds. Near-normal joints of Labradors showed greater lateral AFH coverage compared to those of German Shepherds; whereas, dorsal AFH coverage did not differ between the two breeds. A steeper acetabular slope angle was noted in normal and near-normal CFJS of German Shepherds compared to Labrador Retrievers. The inclination angle of near-normal joints was greater in Labrador Retrievers compared to German Shepherds. Overall, normal and near-normal CFJS of German Shepherds had lesser AFH coverage and steeper acetabular slope angle compared to Labrador Retrievers. Labrador Retrievers and German Shepherds with CE-angles < 27° and < 21.8°, dorsal AFH coverage width indices < 51 and < 49%, and/or dorsal AFH coverage area indices < 53 and < 50%, respectively, may be consistent with CHD. Thus, the authors would recommend excluding subjects with lower values from breeding. Validating the reported measurements is still warranted.

中文翻译：

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拉布拉多猎犬和德国牧羊犬正常和接近正常髋股构象的放射线定量：一项比较研究

犬髋关节发育不良（CHD）是一种影响大型犬的多因素疾病，与关节松弛和不协调有关，使它们容易患上骨关节炎。该研究的目的是客观比较拉布拉多猎犬和德国牧羊犬在扩展腹背X光片上正常和接近正常的髋股关节（CFJS）的构象。根据 FCI 评分系统建立的形态测量标准，研究组被分为正常和接近正常的 CFJS。确定每组的中心边缘（CE）角、诺伯格角（NA）、背侧 AFH 覆盖宽度和面积指数、髋臼倾斜（AS）角和倾斜角。CE角和AS角是根据先前描述的人体技术修改的。背侧 AFH 覆盖的宽度和面积通过相应的股骨头直径和面积进行标准化。使用不配对的双尾 t 检验比较组间的变量。斯皮尔曼相关系数确定了所选变量之间的关系。在拉布拉多犬中，正常的 CFJS 与接近正常的 CFJS 相比，CE 角（横向覆盖）和背侧 AFH 覆盖面积指数（背侧覆盖）更大。在德国牧羊犬中，正常髋关节与接近正常髋关节相比，横向 AFH 覆盖范围（CE 角和 NA）更大；然而，两组之间的背侧 AFH 覆盖范围没有差异。两个品种的正常 CFJS 和接近正常 CFJS 的横向 AFH 覆盖率都更大。在拉布拉多犬中，接近正常的 CFJS 的倾斜角度比正常的 CFJS 更大。与德国牧羊犬相比，拉布拉多犬的正常 CFJS 显示出更大的侧面和背部 AFH 覆盖范围。与德国牧羊犬相比，拉布拉多犬接近正常的关节显示出更大的横向 AFH 覆盖范围；然而，两个品种之间的背部 AFH 覆盖范围没有差异。与拉布拉多猎犬相比，德国牧羊犬的正常和接近正常的 CFJS 具有更陡的髋臼倾斜角度。与德国牧羊犬相比，拉布拉多猎犬接近正常关节的倾斜角度更大。总体而言，与拉布拉多猎犬相比，正常和接近正常的德国牧羊犬 CFJS 的 AFH 覆盖范围较小，髋臼倾斜角度较陡。CE 角 < 27° 和 < 21.8°、背侧 AFH 覆盖宽度指数 < 51 和 < 49% 和/或背侧 AFH 覆盖面积指数分别 < 53 和 < 50% 的拉布拉多猎犬和德国牧羊犬可能与冠心病。因此，作者建议将具有较低值的受试者排除在育种之外。仍然有必要验证报告的测量结果。