骨科英文书籍精读（155）｜腕掌关节脱位
JOINT INJURIES
Any finger joint may be injured by a direct blow (often the overlying skin is damaged), or by an angulation force, or by the straight finger being forcibly stubbed. The affected joint is swollen, tender and too painful to move. X-rays may show that a fragment of bone has been sheared off or avulsed.
CARPO-METACARPAL DISLOCATION
The thumb is most frequently affected and clinically the injury then resembles a Bennett’s fracturedislocation; however, x-rays reveal proximal subluxation or dislocation of the first metacarpal bone without a fracture. The displacement is easily reduced by traction and hyperpronation, but reduction is unstable and can be held only by a K-wire driven through the metacarpal into the carpus. The wire is removed after 5 weeks but a protective splint should be worn for 8 weeks because of the risk of instability.
Chronic instability can occur. This is treated prior to arthritis developing, by using part of the flexor carpi radialis tendon to reconstruct the ruptured and incompetent palmar ligament of the CMC joint.
The other carpo-metacarpal joints are also sometimes dislocated, typically when a motorcyclist, holding the handlebars, strikes an object and the hand is driven backwards. The hand swells up rapidly and the diagnosis is easily missed unless a true lateral x-ray is carefully examined. Closed manipulation is usually successful, although a K-wire is recommended to prevent the joint from dislocating again.
Late presentation
Late presentation or secondary arthritis is treated by joint fusion. However, if just the fifth CMC joint is involved, a neat operation is to fuse the base of the fourth to the fifth metacarpal and then excise the articular surface of the fifth. This will maintain movement at the fourth CMC, so allowing the ulnar side of the hand to ‘cup’ around during grip.
---from 《Apley’s System of Orthopaedics and Fractures》
重点词汇整理：
shear /ʃɪr/n. 切变v. 剪（羊或其他动物的）毛；剪（头发）；（受剪切力作用而）断裂
fragment 碎片
ligament韧带
grip /ɡrɪp/n. 紧握；柄；支配；握拍方式；拍柄绷带vt. 紧握；夹紧vi. 抓住
However, if just the fifth CMC joint is involved, a neat operation is to fuse the base of the fourth to the fifth metacarpal and then excise the articular surface of the fifth. This will maintain movement at the fourth CMC, so allowing the ulnar side of the hand to ‘cup’ around during grip.然而，如果只涉及第五个腕掌关节，一个简洁的手术是融合第四掌至第五掌的基部，然后切除第五掌的关节面。这将保持在第四腕掌关节的运动，所以允许手的尺侧在握的过程中呈现“杯状”。（见下图）
百度翻译：
关节损伤
任何手指关节都可能受到直接打击（通常上覆皮肤受损），或角度力，或直指被强行戳断。受影响的关节肿胀，疼痛，无法活动。X光片可能显示骨头碎片被剪断或撕裂。
腕掌关节脱位
拇指最常受累，临床上这种损伤类似于Bennett骨折脱位；然而，x光片显示第一掌骨近端半脱位或脱位，没有骨折。牵引和过度旋前很容易减少移位，但复位不稳定，只能通过一根穿过掌骨进入腕骨的K形钢丝固定。5周后取下钢丝，但由于存在不稳定的风险，应戴上保护夹板8周。
可能会出现慢性不稳定。这是在关节炎发展之前，通过使用部分桡侧腕屈肌肌腱重建断裂和功能不全的CMC关节掌侧韧带。
另一个腕掌关节也有几次脱臼，典型的情况是，骑摩托车的人握着车把，撞到一个物体上，手被向后推。手迅速肿胀，除非仔细检查侧位x光片，否则很容易漏诊。闭合操作通常是成功的，尽管建议使用K形钢丝防止关节再次脱位。
晚期表现
晚期或继发性关节炎采用关节融合术治疗。然而，如果只涉及第五个腕掌关节，一个简洁的手术是融合第四掌至第五掌的基部，然后切除第五掌的关节面。这将保持在第四腕掌关节的运动，所以允许手的尺侧在握的过程中呈现“杯状”。