骨科英文书籍精读（71）｜肩关节后脱位（2）
Treatment
The acute dislocation is reduced (usually under general anaesthesia) by pulling on the arm with the shoulder in adduction; a few minutes are allowed for the head of the humerus to disengage and the arm is then gently rotated laterally while the humeral head is pushed forwards. If reduction feels stable the arm is immobilized in a sling; otherwise the shoulder is held widely abducted and laterally rotated in an airplane type splint for 3–6 weeks to allow the posterior capsule to heal in the shortest position. Shoulder movement is regained by active exercises.
Complications
Unreduced dislocation At least half the patients with posterior dislocation have ‘unreduced’ lesions when first seen. Sometimes weeks or months elapse before the diagnosis is made and up to two thirds of posterior dislocations are not recognised initially. Typically the patient holds the arm internally rotated; he cannot abduct the arm more than 70–80 degrees, and if he lifts the extended arm forwards he cannot then turn the palm upwards. If the patient is young, or is uncomfortable and the dislocation fairly recent, open reduction is indicated. This is a difficult procedure. It is generally done through a delto-pectoral approach; the shoulder is reduced and the defect in the humeral head can then be treated by transferring the subscapularis tendon into the defect (McLaughlin procedure). Alternatively, the defect on the humeral head can be bone grafted. A useful technique for treating a defect smaller than 40 percent of the humeral head is to transfer of the lesser tuberosity together with the subscapularis into the defect. For defects larger than this a hemiarthroplasty may be considered.
Late dislocations, especially in the elderly, are best left, but movement is encouraged. Recurrent dislocation or subluxation Chronic posterior instability of the shoulder is discussed in Chapter 13.
---from 《Apley’s System of Orthopaedics and Fractures》
重点词汇整理：
disengage/ˌdɪsɪnˈɡeɪdʒ/vt. 使脱离；解开；解除
fairly /ˈferli/adv. 相当地；公平地；简直
subscapularis /'sʌb'skæpju'lɛəris/n. 肩胛下肌
Alternatively, /ɔːlˈtɜːrnətɪvli/adv. 要不，或者；非此即彼；二者择一地；作为一种选择
hemiarthroplasty 半关节成形术
百度翻译：
治疗
在全身麻醉下，用内收的肩膀拉动手臂，可以减少急性脱位；允许几分钟的时间让肱骨头脱离，然后在肱骨头向前推的同时，轻轻地侧向旋转手臂。如果复位感觉稳定，手臂固定在吊索上；否则，肩关节被广泛外展，并在飞机式夹板上横向旋转3-6周，以使后囊在最短的位置愈合。肩部运动通过积极的运动恢复。
并发症
未复位脱位至少有一半的后脱位患者第一次见到时有“未复位”病变。有时几周或几个月后才作出诊断，多达三分之二的后脱位最初没有被识别出来。通常情况下，患者保持手臂内部旋转；他不能将手臂外展超过70-80度，如果他向前抬起伸出的手臂，他就不能将手掌向上转动。如果患者年轻，或不舒服，且脱位最近，则应进行切开复位。这是一个困难的过程。一般通过胸三角入路进行；肩部缩小，肱骨头的缺损可以通过肩胛下肌腱转移到缺损处来治疗（McLaughlin手术）。另外，肱骨头上的缺损可以进行骨移植。治疗小于肱骨头40%的缺损的一种有用的技术是将小结节和肩胛下肌一起转移到缺损处。对于大于此的缺陷，可考虑采用半关节置换术。
晚期脱臼，尤其是老年人，最好留下来，但应鼓励活动。复发性脱位或半脱位肩关节慢性后部不稳在第13章讨论。