LATE COMPLICATIONS
DELAYED UNION
The timetable on page 692 is no more than a rough guide to the period in which a fracture may be expected to unite and consolidate. It must never be relied upon in deciding when treatment may be discontinued. If the time is unduly prolonged, the term ‘delayed union’ is used.
Causes
Factors causing delayed union can be summarized as:
biological, biomechanical or patient-related.
BIOLOGICAL
Inadequate blood supply A badly displaced fracture of a long bone will cause tearing of both the periosteum and interruption of the intramedullary blood supply. The fracture edges will become necrotic and dependent on the formation of an ensheathing callus mass to bridge the break. If the zone of necrosis is extensive, as might occur in highly comminuted fractures, union may be hampered.
Severe soft tissue damage Severe damage to the soft tissues affects fracture healing by: (1) reducing the effectiveness of muscle splintage; (2) damaging the local blood supply and (3) diminishing or eliminating
the osteogenic input from mesenchymal stem cells within muscle.
Periosteal stripping Over-enthusiastic stripping of periosteum during internal fixation is an avoidable cause of delayed union.
BIOMECHANICAL
Imperfect splintage Excessive traction (creating a fracture gap) or excessive movement at the fracture site will delay ossification in the callus. In the forearm and leg a single-bone fracture may be held apart by an intact fellow bone.
Over-rigid fixation Contrary to popular belief, rigid fixation delays rather than promotes fracture union. It is only because the fixation device holds the fragments so securely that the fracture seems to be ‘uniting’. Union by primary bone healing is slow, but provided stability is maintained throughout, it does eventually occur.
Infection Both biology and stability are hampered by active infection: not only is there bone lysis, necrosis and pus formation, but implants which are used to hold the fracture tend to loosen.
PATIENT RELATED
In a less than ideal world, there are patients who are:
· Immense
· Immoderate
· Immovable
· Impossible.
These factors must be accommodated in an appropriate fashion.
Clinical features
Fracture tenderness persists and, if the bone is subjected to stress, pain may be acute.
On x-ray, the fracture line remains visible and there is very little or incomplete callus formation or periosteal reaction. However, the bone ends are not sclerosed or atrophic. The appearances suggest that, although the fracture has not united, it eventually will.
Treatment
CONSERVATIVE
The two important principles are: (1) to eliminate any possible cause of delayed union and (2) to promote healing by providing the most appropriate environment. Immobilization (whether by cast or by internal fixation) should be sufficient to prevent shear at the fracture site, but fracture loading is an important stimulus to union and can be enhanced by: (1) encouraging muscular exercise and (2) by weightbearing in the cast or brace. The watchword is patience; however, there comes a point with every fracture where the illeffects of prolonged immobilization outweigh the advantages of non-operative treatment, or where the risk of implant breakage begins to loom.
OPERATIVE
Each case should be treated on its merits; however, if union is delayed for more than 6 months and there is no sign of callus formation, internal fixation and bone grafting are indicated. The operation should be planned in such a way as to cause the least possible damage to the soft tissues.
---from 《Apley’s System of Orthopaedics and Fractures》P716
重点词汇整理：
unduly /ˌʌnˈduːli/adv. 过度地；不适当地；不正当地
biological, biomechanical or patient-related.生物学、生物力学或与病人相关
periosteum /,pɛrɪ'ɑstɪəm/
n. [解剖] 骨膜；管膜
mesenchymal stem cells 间充质干细胞
Periosteal stripping 骨膜剥离
enthusiastic /ɪnˌθuːziˈæstɪk/adj. 热情的；热心的；狂热的
ossification/ˌɑːsɪfɪˈkeɪʃn/n. 骨化；成骨；（思想的）僵化
Contrary to popular belief, rigid fixation delays rather than promotes fracture union.与普遍的看法相反，刚性固定延迟而不是促进骨折愈合。
hamper /ˈhæmpər/n. 食盒，食篮；阻碍物vt. 妨碍；束缚；使困累
lysis/'laɪsɪs/n. （生物）溶胞，溶菌；溶解，分解；（发烧等生病过程）消退
pus /pʌs/n. 脓；脓汁
Immoderate /ɪˈmɑːdərət/adj. 无节制的，过度的；不适中的
Fracture tenderness 骨折压痛
tenderness /ˈtendərnəs/n. 亲切；柔软；柔和；敏感；棘手
remains visible 仍然是可见的
On x-ray, the fracture line remains visible and there is very little or incomplete callus formation or periosteal reaction. 在x线片上，骨折线清晰可见，很少或不完整的骨痂形成或骨膜反应。
sclerosed or atrophic硬化或萎缩性
/'sklɛərost/adj. 硬化的；患硬化症的v. 硬化（sclerose的过去式和过去分词）
/æ'trɔfik/adj. 萎缩的
CONSERVATIVE /kənˈsɜːrvətɪv/n. 保守派，守旧者adj. 保守的
promote/prəˈmoʊt/vi. 成为王后或其他大于卒的子vt. 促进；提升；推销；发扬
Immobilization/ɪˌmoʊbələˈzeɪʃn/n. 使停止流通，固定
shear at the fracture site 骨折端的剪切力
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
The watchword is patience; 口号是耐心;
watchword/ˈwɑːtʃwɜːrd/n. 口号；标语；口令；暗号
prolonged immobilization 长期制动
the risk of implant breakage begins to loom.植入物断裂的风险开始显现。
merits /'mɛrɪts/n. 优点（merit的复数）；功绩；是非曲直
internal fixation and bone grafting are indicated建议采用内固定和植骨
百度翻译：
晚期并发症
延迟联合
第692页的时间表只不过是一个粗略的指南，说明骨折可能会愈合和巩固的时期。决不能依赖它来决定什么时候可以停止治疗。如果时间过长，则使用“延迟结合”一词。
原因
导致延迟愈合的因素可归纳为：
生物学的，生物力学的或与病人相关的。
生物学的
供血不足长骨严重移位骨折会导致骨膜撕裂和髓内供血中断。骨折边缘会坏死，并依赖于形成一个包涵骨痂团来桥接骨折。如果坏死区是广泛的，如高度粉碎性骨折，愈合可能会受到阻碍。
严重的软组织损伤严重的软组织损伤通过以下方式影响骨折愈合：（1）降低肌肉夹板的有效性；（2）损伤局部血供；（3）减少或消除肌内间充质干细胞的成骨输入。
内固定时骨膜剥离过度是延迟愈合的一个可避免的原因。
生物力学
不完美的夹板过度牵引（造成骨折间隙）或骨折部位过度移动会延迟骨痂的骨化。在前臂和腿部，一个完整的同伴骨可以将一个单独的骨折分开。
与人们普遍认为的相反，过硬固定延迟而不是促进骨折愈合。这仅仅是因为固定装置把碎片固定得如此牢固，以至于骨折看起来是“结合”在一起的。原发性骨愈合愈合缓慢，但只要始终保持稳定，最终会发生。
感染的生物学和稳定性都受到主动感染的阻碍：不仅有骨溶解、坏死和脓液形成，而且用于固定骨折的植入物往往会松动。
与患者相关
在一个不太理想的世界里，有些病人是：
·巨大
·过分
·不可移动
·不可能。
这些因素必须以适当的方式加以考虑。
临床特征
骨折压痛持续存在，如果骨头受到应力作用，疼痛可能是急性的。
x线片可见骨折线，骨痂形成或骨膜反应很少或不完全。然而，骨头末端没有硬化或萎缩。表面看来，虽然骨折还没有愈合，但最终还是会愈合的。
治疗
保守的
两个重要的原则是：（1）消除延迟愈合的任何可能原因；（2）通过提供最合适的环境促进愈合。固定（无论是石膏固定还是内固定）应足以防止骨折部位的剪切，但骨折负荷是促进骨折愈合的一个重要刺激因素，可以通过：（1）鼓励肌肉锻炼和（2）在石膏或支架中负重来增强。我们的口号是耐心；然而，每一次骨折都会出现这样的情况：长期固定的不良影响超过非手术治疗的好处，或者植入物断裂的风险开始显现。
手术的
每个病例应根据其优点进行治疗，但如果愈合延迟超过6个月，且没有骨痂形成的迹象，则应进行内固定和骨移植。手术的计划应尽量减少对软组织的损伤。
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