Igei Takahiro, Nakasone Satoshi, Ishihara Masato, Onaga Masamichi, Washizaki Fumiyuki, Kuniyoshi Sakura, Nishida Kotaro
Department of Orthopedic Surgery, Graduate School of Medicine, University of the Ryukyus, 207, Uehara, Nishihara, Okinawa, Japan.
Department of Orthopedic Surgery, Graduate School of Medicine, University of the Ryukyus, 207, Uehara, Nishihara, Okinawa, Japan.
J Orthop Sci. 2025 Jul;30(4):656-661. doi: 10.1016/j.jos.2024.10.008. Epub 2024 Nov 12.
Patients with developmental dysplasia of the hip (DDH) undergo curved periacetabular osteotomy (CPO) to prevent progressive osteoarthritis. The acetabulum's morphology varies with in each DDH type. Therefore, developing a three-dimensional preoperative plan is important in CPO. However, the optimal rotation angle of the osteotomized bone remains unclear. This study aimed to examine the contact pressure (CP) of the acetabular cartilage in each DDH type using the finite element analysis and the optimal rotation angle of the osteotomized bone in surgical simulation.
This study included 23 patients (24 hips) with DDH who underwent CPO. The DDH type was determined based on a previously reported DDH type classification using radar charts. Four patients, with each patient presenting with one deficiency type, were selected for analysis. The preoperative computed tomography scan data of each patient were analyzed using a finite element analysis software. Based on each DDH type, the following CPO models were established: the preoperative model, the model rotated 10°, 20°, 30°, and 40° laterally, each lateral rotation model with 10° anterior rotation, and each lateral rotation model with 10° external rotation. Furthermore, the acetabular cartilage and the femoral head cartilage were created. The mesh model based on a 4-mm tetrahedron was generated from the CPO model. The load was set in the one-leg standing position (femur: 500 N, grater trochanter: 1000 N). The medial pubic bone, distal femur, and superior rim of the ilium were constrained. The CP of the acetabular cartilage and the number of contact surfaces in each model were evaluated. The rotation angle that was most effective in reducing the CP was examined.
According to the mean CP, the optimal rotation angles of the osteotomized bone in mild, anterior, posterior, and global type deficiencies were 20° laterally, 30° laterally, 30° laterally with 10° anterior rotation, and 30° laterally with 10° anterior rotation, respectively. Based on the contour diagram, the CPO models rotated anteriorly or externally increased the contact surface. The CP of the models rotated 40° laterally did not improve to greater extent than that of the models rotated 30° laterally.
The optimal rotation angle of the osteotomized bone should be determined based on the DDH type.
发育性髋关节发育不良（DDH）患者接受髋臼周围弧形截骨术（CPO）以预防进行性骨关节炎。髋臼形态在每种DDH类型中各不相同。因此，制定三维术前计划在CPO中很重要。然而，截骨后的最佳旋转角度仍不明确。本研究旨在通过有限元分析检查每种DDH类型中髋臼软骨的接触压力（CP），并在手术模拟中确定截骨后的最佳旋转角度。
本研究纳入23例（24髋）接受CPO的DDH患者。根据先前报道的使用雷达图的DDH类型分类确定DDH类型。选择4例患者，每位患者呈现一种缺陷类型进行分析。使用有限元分析软件分析每位患者的术前计算机断层扫描数据。基于每种DDH类型，建立以下CPO模型：术前模型、向外侧旋转10°、20°、30°和40°的模型，每个外侧旋转模型再向前旋转10°，以及每个外侧旋转模型再向外旋转10°。此外，创建髋臼软骨和股骨头软骨。从CPO模型生成基于4毫米四面体的网格模型。在单腿站立位设置负荷（股骨：500 N，大转子：1000 N）。对耻骨内侧、股骨远端和髂骨上缘进行约束。评估每个模型中髋臼软骨的CP和接触表面数量。检查对降低CP最有效的旋转角度。
根据平均CP，轻度、前侧、后侧和整体型缺陷中截骨后的最佳旋转角度分别为向外侧20°、向外侧30°、向外侧30°并向前旋转10°、向外侧30°并向前旋转10°。根据等高线图，向前或向外旋转的CPO模型增加了接触表面。向外侧旋转40°的模型的CP改善程度不如向外侧旋转30°的模型。
应根据DDH类型确定截骨后的最佳旋转角度。
