Yu Jin, Griffon Dominique J, Wisser Gary, Mostafa Ayman A, Dong Fanglong
College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA, United States.
Center for Excellence in Teaching and Learning, Western University of Health Sciences, Pomona, CA, United States.
Front Vet Sci. 2023 Mar 3;10:1118755. doi: 10.3389/fvets.2023.1118755. eCollection 2023.
Cranial cruciate ligament deficiency (CCLD) results in internal rotational instability of the stifle (RLS). By contrast, tibial torsion (TT) is an anatomical feature of the tibia along its longitudinal axis. The objective of this study was to validate a dynamic radiographic technique to measure internal rotational laxity of the stifle and differentiate it from TT. Models included transection of the CCL for RLS and an osteotomy for TT. One limb within eight pairs of canine cadaveric hind limbs was randomly assigned to CCLD. The contralateral limb underwent TT, followed by CCLD. Neutral and stress radiographs were taken with the limb in a custom rotating 3-D printed positioning device before and after each modification. The position of the calcaneus on neutral views and the magnitude of its displacement under standardized torque were compared within limbs and between groups. Transection of the CCL increased the magnitude of displacement of the calcaneus by 1.6 mm (0.3-3.1 mm, < 0.05) within limbs. The lateral calcaneal displacement (dS-dN) tended to be greater when CCLD limbs were compared to limbs with intact CCL. A magnitude of calcaneal displacement of 3.45 mm differentiated limbs with RLS from intact limbs with 87.5% sensitivity and 68.7% specificity. The calcaneus was displaced further laterally by about 3 mm on neutral radiographs (dN) when limbs with experimental TT were compared to those without TT ( < 0.05). A calcaneus located at least 3.25 mm from the sulcus differentiated limbs with TT from intact limbs with 87.5% sensitivity and 87.5% specificity. The technique reported here allowed detection of RLS, especially within limbs. A calcaneus located at least 3.25 mm on neutral radiographs of large dogs should prompt a presumptive diagnosis of TT.
颅交叉韧带缺失（CCLD）会导致 stifle（RLS）的内旋不稳定。相比之下，胫骨扭转（TT）是胫骨沿其纵轴的一种解剖学特征。本研究的目的是验证一种动态放射成像技术，以测量 stifle 的内旋松弛度并将其与 TT 区分开来。模型包括用于 RLS 的 CCL 横断和用于 TT 的截骨术。八对犬类尸体后肢中的一条肢体被随机分配到 CCLD 组。对侧肢体进行 TT，然后进行 CCLD。在每次修改前后，将肢体置于定制的 3D 打印旋转定位装置中拍摄中立位和应力位 X 光片。比较肢体内部和组间跟骨在中立位视图上的位置及其在标准化扭矩下的位移大小。CCL 横断使肢体内部跟骨的位移大小增加了 1.6 毫米（0.3 - 3.1 毫米，<0.05）。与 CCL 完整的肢体相比，CCLD 肢体的外侧跟骨位移（dS - dN）往往更大。跟骨位移大小为 3.45 毫米时，可将 RLS 肢体与完整肢体区分开来，灵敏度为 87.5%，特异性为 68.7%。与无 TT 的肢体相比，实验性 TT 肢体在中立位 X 光片（dN）上跟骨向外侧进一步位移约 3 毫米（<0.05）。跟骨与沟的距离至少为 3.25 毫米时，可将 TT 肢体与完整肢体区分开来，灵敏度为 87.5%，特异性为 87.5%。此处报道的技术能够检测到 RLS，尤其是在肢体内部。大型犬中立位 X 光片上跟骨位置至少为 3.25 毫米时，应提示 TT 的初步诊断。
