肱骨大结节骨折向下移位的临床意义

Inferior displacement sign in fracture of humeral greater tuberosity

目的探讨肩关节正位X线片上表现为“向下移位”的肱骨大结节骨折的临床意义。方法回顾性分析2008年1月至2015年6月期间收治的24例患者临床及影像学资料，男10例，女14例；平均年龄54岁（19～68岁）；左侧8例，右侧16例。此24例患者肩关节正位X线片均表现为大结节骨折与肱骨头之间的关系接近正常，大结节骨折向肱骨干侧移位，其下缘与肱骨干外侧皮质最上缘之间出现重叠，定义为肱骨大结节骨折“向下移位”。24例患者同时接受CT检查，了解大结节骨折移位方向及是否合并肱骨解剖颈骨折。结果10例患者肩关节正位X线片上发现轻微移位的解剖颈骨折。CT检查结果发现23例患者存在解剖颈骨折；22例患者肱骨大结节向后移位，2例患者向后下移位。影像学测量显示：向后移位距离平均为（10．5±4．5）mm。肱骨头和肱骨干之间的移位程度平均为（2．54±1，5）min，颈干角平均为147．2°±9．2°；肱骨头与大结节之间的距离平均为（10．8±3．4）mm，大结节下缘与肱骨干之间的重叠程度平均为（12．5±5．9）mm。Pearson相关性分析显示大结节向下移位程度与肱骨头顶点．大结节顶点之间的距离无相关性（P〉0．05），与颈干角有相关性（P〈0．05）。结论肩关节正位X线片上表现为肱骨大结节骨折“向下移位”的实质为向后移位的大结节骨折在正位X线片上的重叠影。向后方移位的大结节骨折伴轻微移位的解剖颈骨折是肱骨近端外翻压缩骨折的一种表现。肱骨大结节骨折“向下移位”高度提示存在隐匿性或轻微移位肱骨颈骨折。

Objective To explore the clinical significance of the ＂inferior displacement sign＂ on the initial anterioposterior （AP） view X-ray for fractures of humeral greater tuberosity. Methods This study retrospectively analyzed the imaging and clinical data of 24 patients with isolated fracture of humeral greater tuberosity who had sought medical treatment during the period from January 2008 to June 2015. They were 10 males and 14 females, with an average age of 54 years （from 19 to 68 years）. Laterality： 8 left sides and 16 right sides. The AP view X-ray films of the 24 patients present the ＂inferior displacement sign＂ defined as the inferior cortical margin of the greater tuberosity overlapping the proximal humeral shaft on the initial AP view. The patients received further CT examination to determine the displacement direction and whether the humeral neck fracture was complicated. Results A slight displacement of humeral anatomic neck fracture was shown on the initial AP view X-ray in 10 patients. Further CT examination revealed that humeral anatomic neck fracture was confirmed in 23 patients, the greater tuberosity was displaced posteriorly in 22 patients and posteroinferiorly in 2 patients. Radiographic measurements showed： the mean posterior displacement was 10. 5 ± 4. 5 mm; the displacement between the humeral head and the humeral shaft was 2.5 ± 1.5 mm; the neck shaft angle was 147.2° ± 9. 2°; the distance between the humeral head and greater tuberosity was 10.8 ± 3.4 mm; the overlap between the inferior edge of greater tuberosity and the upper edge of lateral humeral shaft was 12.5±5.9 mm. Pearson correlation analysis showed no correlation between the overlap and the head-tuberosity distance （P 〉 0. 05）, but a significant correlation between the overlap and the neck-shaft angle （ P 〈 0.05 ）. Conclusions The ＂inferior displacement sign＂ on the initial AP view X-ray is actually the overlap of posterior displaced greater tuberosity fracture shown on the X-ray. The posterior displaced greater tuberosity fracture complicated with slight displaced anatomic neck fracture is a presentation of the valgus impacted fracture of the proximal humerus. The ＂inferior displacement sign＂ in the fracture of humeral greater tuberosity can highly suggest the presence of occult or slight displacement of the humeral anatomic neck fracture.