Department of Orthopaedic Surgery, Graduate School of Medicine, Osaka University, Suita, Japan.
Department of Orthopaedic Surgery, Graduate School of Medicine, Osaka University, Suita, Japan.
J Shoulder Elbow Surg. 2019 Sep;28(9):1764-1770. doi: 10.1016/j.jse.2019.02.006. Epub 2019 Apr 28.
Contracture of the elbow after obstetric brachial plexus palsy (OBPP) is well known; however, details of the 3-dimensional (3D) morphologic changes in the elbow joint in OBPP have not been clarified. This study aimed to clarify the 3D morphologic changes in the elbow joint by focusing on the distal humerus with flexion contracture in upper OBPP. We tested the hypothesis that the shape of the distal humerus with flexion contracture in upper OBPP is hypoplastic in the trochlea, capitellum, and olecranon fossa.
We retrospectively studied 20 patients with elbow flexion contracture and residual OBPP. The approximate radius of the distal humerus, the shortest distance between the olecranon and coronoid fossa, and the size of the olecranon fossa were measured and compared between the affected and normal sides using 3D bone models to assess the distal humerus morphology.
The average radius of the distal humerus was smaller on the affected side than on the normal side. Furthermore, the average distance between the olecranon and coronoid fossa was greater and the average size of the olecranon fossa was smaller on the affected side than on the normal side. The size of the distal humerus was significantly smaller and the olecranon fossa was significantly shallower on the affected side.
Consistent with our original hypothesis, the distal humerus with flexion contracture in upper OBPP was hypoplastic. The shallow olecranon fossa might prevent full extension of the elbow even though soft tissue contracture release is performed. We recommend evaluation of the morphology of the olecranon fossa to determine the treatment plan for elbow flexion contracture with OBPP.
产伤性臂丛神经麻痹（OBPP）后肘部挛缩是众所周知的；然而，OBPP 中肘部关节的三维（3D）形态变化的细节尚未阐明。本研究旨在通过关注上 OBPP 中伴有屈肌挛缩的肱骨远端来阐明肘部关节的 3D 形态变化。我们检验了这样一个假设，即上 OBPP 中伴有屈肌挛缩的肱骨远端在滑车、肱骨小头和鹰嘴窝处存在发育不良。
我们回顾性研究了 20 例肘部屈曲挛缩和残余 OBPP 的患者。使用 3D 骨骼模型测量和比较患侧和健侧的肱骨远端近似半径、鹰嘴窝和冠状突窝之间的最短距离以及鹰嘴窝的大小，以评估肱骨远端的形态。
患侧肱骨远端的平均半径小于健侧。此外，患侧鹰嘴窝和冠状突窝之间的平均距离更大，鹰嘴窝的平均大小也更小。患侧肱骨远端的尺寸明显较小，鹰嘴窝明显较浅。
与我们最初的假设一致，上 OBPP 中伴有屈肌挛缩的肱骨远端发育不良。即使进行软组织挛缩松解，浅的鹰嘴窝也可能妨碍肘部完全伸展。我们建议评估鹰嘴窝的形态，以确定 OBPP 引起的肘部屈曲挛缩的治疗计划。
