Types of internal fixation
Interfragmentary screws Screws that are only partially threaded (a similar effect is achieved by overdrilling the ‘near’ cortex of bone) exert a compression or ‘lag’ effect when inserted across two fragments. The technique is useful for reducing single fragments onto the main shaft of a tubular bone or fitting together fragments of a metaphyseal fracture.
Wires (transfixing, cerclage and tension-band) Transfixing wires, often passed percutaneously, can hold major fracture fragments together. They are used in situations where fracture healing is predictably quick (e.g. in children or for distal radius fractures), and some form of external splintage (usually a cast) is applied as supplementary support.
Cerclage and tension-band wires are essentially loops of wire passed around two bone fragments and then tightened to compress the fragments together. When using cerclage wires, make sure that the wires hug the bone and do not embrace any of the close lying nerves or vessels.
Both techniques are used for patellar fractures: the tension-band wire is placed such that the maximum compressive force is over the tensile surface, which is usually the convex side of the bone.
Plates and screws This form of fixation is useful for treating metaphyseal fractures of long bones and diaphyseal fractures of the radius and ulna. Plates have five different functions:
1. Neutralization – when used to bridge a fracture and supplement the effect of interfragmentary lag screws; the plate is to resist torque and shortening.
2. Compression – often used in metaphyseal fractures where healing across the cancellous fracture gap may occur directly, without periosteal callus. This technique is less appropriate for diaphyseal fractures and there has been a move towards the use of long plates that span the fracture, thus achieving some stability without totally sacrificing the biological (and callus producing) effect of movement.
3. Buttressing – here the plate props up the ‘overhang’ of the expanded metaphyses of long bones (e.g. in treating fractures of the proximal tibial plateau).
4. Tension-band – using a plate in this manner, again on the tensile surface of the bone, allows compression to be applied to the biomechanically more advantageous side of the fracture.
5. Anti-glide – by fixing a plate over the tip of a spiral or oblique fracture line and then using the plate as a reduction aid, the anatomy is restored with minimal stripping of soft tissues. The position of the plate acts to prevent shortening and recurrent displacement of the fragments.
Intramedullary nails These are suitable for long bones. A nail (or long rod) is inserted into the medullary canal to splint the fracture; rotational forces are resisted by introducing transverse interlocking screws that transfix the bone cortices and the nail proximal and distal to the fracture. Nails are used with or without prior reaming of the medullary canal; reamed nails achieve an interference fit in addition to the added stability from interlocking screws, but at the expense of temporary loss of the intramedullary blood supply.
---from 《Apley’s System of Orthopaedics and Fractures》P701-703
重点词汇整理：
metaphyseal fracture干骺端骨折
percutaneously经由皮肤地
cutaneous /kjuˈteɪniəs/adj. 皮肤的；侵犯皮肤的
predictably /prɪˈdɪktəbli/adv. 可预言地
Cerclage and tension-band wires环扎和张力带钢丝
Cerclage /sə:'klædʒ/n. （折骨端）环扎术
essentially /ɪˈsenʃəli/adv. 本质上；本来
loops of wire 钢丝环
convex /ˈkɑːnveks/n. 凸面，凸出部分
tensile /ˈtensl/adj. [力] 拉力的；张力的；可伸长的；可拉长的
diaphyseal fractures 骨干骨折
Neutralization/ˌnuːtrələˈzeɪʃn/n. [化学] 中和；[化学] 中和作用；中立状态
interfragmentary lag screws 拉力螺钉
torque /tɔːrk/n. 转矩，[力] 扭矩；项圈，金属领圈v. (向轴、螺栓、圆轮等)施以扭动力；(使)沿轴转动；使(绕轴等)扭转；施加转矩
cancellous /'kænsələs/adj. 多孔的；罗眼状的（等于cancellate）
periosteal /,peri'ɔstiəl/adj. 骨膜的
Buttress /ˈbʌtrəs/n. 扶壁；山边扶壁状凸出部分；支持力量
prop /prɑːp/v. 支撑；放置；用……撑住（某物）
fractures of the proximal tibial plateau
胫骨近端平台骨折
plateau/plæˈtoʊ/n. 高原；稳定水平；托盘；平顶女帽vi. 达到平衡；达到稳定时期
Tension-band张力带
glide /ɡlaɪd/v. 滑翔；滑行；悄悄地走；消逝
spiral or oblique fracture螺旋或斜形骨折
the anatomy is restored with minimal stripping of soft tissues. 以最小限度地剥离软组织来恢复解剖。
Intramedullary nails髓内钉 /,intrə,me'dʌləri/adj. [解剖] 髓内的
transverse interlocking screws 横向联锁螺丝
transfix /trænsˈfɪks/vt. 钉住；刺穿；使呆住
Nails are used with or without prior reaming of the medullary canal;使用钉子时，可事先扩髓或不扩髓;
reaming /'ri:miŋ/n. 铰刀；纹孔v. 钻孔；铰除（ream的ing形式）
at the expense of temporary loss of the intramedullary blood supply.以暂时丧失髓内血液供应为代价。
百度翻译：
内固定类型
只有部分螺纹的膈间螺钉（类似的效果是通过过度切削骨的“近”皮质实现的）在插入两个碎片时产生压缩或“滞后”效应。该技术有助于将单个碎片减少到管状骨的主轴上，或将干骺端骨折的碎片装配在一起。
导线（贯穿、环扎和张力带）贯穿导线，通常通过经皮，可将主要骨折碎片固定在一起。在骨折愈合速度快的情况下（例如儿童或桡骨远端骨折），使用某种形式的外夹板（通常是石膏）作为辅助支撑。
环扎带和张力带钢丝基本上是绕着两块骨头碎片的钢丝圈，然后拉紧将碎片压缩在一起。当使用环扎钢丝时，要确保钢丝与骨头紧密结合，不要与任何靠近的神经或血管结合。
这两种技术都用于髌骨骨折：张力带钢丝的放置使得最大压缩力超过张力表面，张力表面通常是骨的凸面。
钢板和螺钉这种固定方式对于治疗长骨干骺端骨折和桡骨和尺骨骨干骨折是有用的。板有五种不同的功能：
一。中和作用-当用于桥接骨折和补充膈间拉力螺钉的作用时；钢板用于抵抗扭矩和缩短。
2。压缩性骨折-常用于干骺端骨折，在这种骨折中，松质骨间隙的愈合可能直接发生，而无骨膜骨痂。这项技术不太适合于骨干骨折，并且已经朝着使用跨越骨折的长钢板的方向发展，从而在不完全牺牲移动的生物（和产生愈伤组织）效应的情况下实现一些稳定性。
三。支撑-在这里，钢板支撑着长骨扩张干骺端的“突出部分”（例如治疗胫骨平台近端骨折）。
四。张力带-以这种方式使用钢板，再次在骨的拉伸表面，允许压缩应用到生物力学上更有利的骨折侧。
5个。抗滑翔-通过将钢板固定在螺旋形或斜形骨折线的顶端，然后使用钢板作为复位辅助，以最小的软组织剥离来恢复解剖。钢板的位置起到防止碎片缩短和反复移位的作用。
髓内钉适用于长骨。将一根钉子（或长杆）插入髓管，用夹板夹住骨折；通过引入横行交锁螺钉来抵抗旋转力，横行交锁螺钉穿过骨皮质和骨折近端和远端的钉子。在髓管扩孔或不扩孔的情况下使用髓内钉；扩孔的髓内钉除了增加了联锁螺钉的稳定性外，还实现了过盈配合，但代价是暂时失去髓内血供。
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