骨科英文书籍精读（78）｜骨折伴脱位
FRACTURE-DISLOCATION
Two-part fracture-dislocations (greater tuberosity with anterior dislocation and lesser tuberosity with posterior) can usually be reduced by closed means.
Three-part fracture-dislocations, when the surgical neck is also broken, usually require open reduction and fixation; the brachial plexus is at particular risk during this operation.
Four-part fracture-dislocations have a poor prognosis; prosthetic replacement is recommended in all but young and very active patients.
Complications
Vascular injuries and nerve injuries
The patient should always be carefully assessed for signs of vascular and nerve injuries, both at the initial examination and again after any operation. The axillary nerve is at particular risk, both from the injury and from surgery.
Avascular necrosis
The reported incidence of avascular necrosis (AVN) of the humeral head ranges from 10–30 percent in three-part fractures and 10 to over 50 percent in four-part fractures. The ability to predict the likelihood of this outcome is important in making the choice between internal fixation and hemiarthroplasty for complex fractures.
The blood-supply of the humeral head is provided mainly by the anterior circumflex artery and its ascending branch (the arcuate artery) which penetrates into the humeral head and arches across subchondrally. Additional blood-supply is provided by vessels entering the posteromedial aspect of the proximal humerus, metaphyseal vessels and vessels of the greater and lesser tuberosities that anastomose with the intraosseous arcuate artery. Thus, in threeand four-part fractures with the only supply coming from the posteromedial vessels, there may still be sufficient perfusion of the humeral head if the head fragment includes a sizeable part of the calcar on the medial side of the anatomical neck. Hertel et al.(2004) have made the point that fractures at the anatomical neck with a medial metaphyseal (calcar) spike shorter than 8 mm carry a high risk of developing humeral head avascular necrosis (see Fig. 24.15).
Disruption of the medial periosteal hinge is another predictor of avascular necrosis and the presence of these two factors combined has a positive predictive value of 98 percent for avascular necrosis of the umeral head. Contrariwise, fractures with an intact medial hinge and/or a large posteromedial metaphyseal spike carry a much better prognosis. The mere number of fracture parts, their degree of displacement and split-head fractures are rated as poor predictors of avascular necrosis, as is the presence of dislocation.
Stiffness of the shoulder
This is a common complication, particularly in elderly patients. Unlike a
frozen shoulder, the stiffness is maximal at the outset. It can be prevented, or at least minimized, by starting exercises early.
Malunion
Malunion usually causes little disability, but loss of rotation may make it difficult for the patient to reach behind the neck or up the back.
---from 《Apley’s System of Orthopaedics and Fractures》
重点词汇整理：
prognosis /prɑːɡˈnoʊsɪs/n. [医] 预后；预知
circumflex /ˈsɜːrkəmfleks/n. 音调符号
adj. 弯曲的；有声调符号的v. 标有抑扬音符；弯曲
anterior circumflex artery 旋前动脉
arcuate /'ɑrkjʊɪt/adj. 弓形的，弯曲的
penetrate/ˈpenətreɪt/vi. 渗透；刺入；看透vt. 渗透；穿透；洞察
subchondrally软骨下地
posteromedial aspect of the proximal humerus,肱骨近端后内侧，
metaphyseal干骺端的
anastomose /ə'næstə,moz/v. 吻合；用吻合术联结
intraosseous骨内的
sizeable /ˈsaɪzəbl/adj. 大的，相当大的
anatomical/ˌænəˈtɑːmɪkl/adj. 解剖的；解剖学的；结构上的
spike /spaɪk/n. 长钉，道钉；钉鞋；细高跟vt. 阻止；以大钉钉牢；用尖物刺穿
Disruption /dɪsˈrʌpʃn/n. 扰乱，打乱，中断
periosteal hinge骨膜铰链
Contrariwise/kənˈtreriwaɪz/adv. 反之，相反；以相反的方式；顽固地
百度翻译：
骨折脱位
通常可以通过闭合方式减少两部分骨折脱位（具有前部脱位的大结节和具有后部的较小结节）。
当手术颈部也破裂时，三部分骨折脱位通常需要切开复位和固定；臂丛神经在此手术过程中特别危险。
四部分骨折脱位的预后较差；除年轻和非常活跃的患者外，所有患者均建议进行假体置换。
难题
血管损伤和神经损伤在初次检查时和任何手术后，应始终仔细评估患者血管和神经损伤的迹象。腋神经特别危险，无论是受伤还是手术。
缺血性坏死
据报道，肱骨头缺血性坏死（AVN）的发生率在三部分骨折中为10-30%，在四部分骨折中为10%至50%以上。预测这种结果的可能性的能力对于在复杂骨折的内固定和半关节成形术之间进行选择是重要的。
肱骨头的血液供应主要由旋前动脉及其上行分支（弓形动脉）提供，其穿过软骨下进入肱骨头和弓形。通过进入肱骨近端后内侧的血管，干骺端血管和与骨内弓形动脉吻合的大结节和小结节血管提供额外的血液供应。因此，在仅有来自后内侧血管的供应的三部分和四部分骨折中，如果头部碎片包括解剖学内侧的大部分跟骨，则可能仍然有足够的肱骨头灌注。脖子。Hertel等（2004）指出，内侧干骺端（calcar）钉短于8 mm的解剖颈部骨折具有发生肱骨头缺血性坏死的高风险（见图24.15）。
内侧骨膜铰链的破坏是缺血性坏死的另一个预测因子，并且这两个因素的组合对于肱骨头的缺血性坏死具有98%的阳性预测值。相反，具有完整内侧铰链和/或大的后内侧干骺端钉的骨折具有更好的预后。骨折部位的数量，移位程度和裂头骨折被认为是缺血性坏死的不良预测因素，脱位的存在也是如此。
肩膀僵硬
这是一种常见的并发症，特别是在老年患者中。不像肩周炎，刚度一开始就最大。通过尽早开始练习可以预防或至少最小化。
畸形愈合
畸形愈合通常导致很少的残疾，但是旋转的丧失可能使患者难以到达颈部或背部。