Isono Arata, Harada Yasuji, Kanno Nobuo, Hara Yasushi
Division of Veterinary Surgery, Department of Veterinary Science, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino-shi, Tokyo, Japan.
Otakibashi Animal Hospital, Shinjuku-ku, Tokyo, Japan.
Vet Comp Orthop Traumatol. 2025 Jul;38(4):162-170. doi: 10.1055/s-0044-1796628. Epub 2024 Nov 21.
Medial patellar luxation (MPL) is prevalent in small dogs; however, the causes vary, and few studies have reported tibial deformities. We aimed to conduct a detailed morphological investigation of internal tibial torsion and internal foot rotation and compare the results between MPL grades to better understand the pathogenesis of MPL.
We performed a morphological study of the tibia and comparison with MPL grade, and established a new parameter, metatarsal orientation relative to the orientation of the tibial tuberosity, the proximal tibia metatarsal angle (PTMTA). The distal tibia metatarsal angle was also established, and tibial torsion angle (TTA), mechanical medial proximal tibial angle, medial distance of the tibial tuberosity/proximal tibial width, and crural rotation angle were compared among the grades of MPL.
The PTMTA was significantly higher in grades 3 and 4 than in the normal group. TTA, medial distance of the tibial tuberosity/proximal tibial width, and mechanical medial proximal tibial angle were significantly higher in grade 4 than in the other grades, which is consistent with previous reports. A correlation was also observed between the PTMTA and the TTA.
The PTMTA functioned as a parameter that included elements of the distal tibia metatarsal angle, TTA, and medial distance of the tibial tuberosity/proximal tibial width, and is considered clinically useful because it can be visually ascertained during palpation. Our results may play a major role in surgical decision-making in the treatment of MPL.
内侧髌骨脱位（MPL）在小型犬中很常见；然而，其病因各不相同，且很少有研究报道胫骨畸形。我们旨在对胫骨内扭转和足部内旋进行详细的形态学研究，并比较MPL不同分级之间的结果，以更好地了解MPL的发病机制。
我们对胫骨进行了形态学研究，并与MPL分级进行比较，建立了一个新参数，即跖骨相对于胫骨结节方向的方向，近端胫骨跖骨角（PTMTA）。还建立了远端胫骨跖骨角，并比较了MPL不同分级之间的胫骨扭转角（TTA）、机械性内侧近端胫骨角、胫骨结节内侧距离/近端胫骨宽度以及小腿旋转角。
3级和4级的PTMTA显著高于正常组。4级的TTA、胫骨结节内侧距离/近端胫骨宽度以及机械性内侧近端胫骨角显著高于其他分级，这与之前的报道一致。PTMTA和TTA之间也观察到相关性。
PTMTA作为一个包含远端胫骨跖骨角、TTA以及胫骨结节内侧距离/近端胫骨宽度等要素的参数，因其在触诊时可直观确定，被认为在临床上有用。我们的结果可能在MPL治疗的手术决策中起主要作用。
