脛骨骨折 | 醫學影像學習園地

脛骨骨折 Tibial fracture

文/王幸婷. 謝博堯. 陳傑龍 圖/江品儀


簡介

脛骨骨折可能是由外傷(trauma),或過度使用(repetitive use)造成,後者造成壓力性骨折(stress fracture)

流行病學

1.
骨折發生於兩種外傷分類:
(1)
高能量外傷(High energy trauma):例如-摩托車或腳踏車意外事故,易造成複雜性、開放性脛骨骨折(complex, open tibia fractures)
(2)
低能量外傷(Low energy trauma):例如-跌倒、持續性或衝擊性運動、跑步,易造成單純的橫向或線性脛骨骨折(simple transverse or linear tibia fracture)
2.
在美國成人和小孩中,closed tibial shaft fracture是長骨骨折最常見的原因。

分類 (依解剖構造)

1.
近端脛骨骨折(Proximal tibial fractures) (Tibial plateau fracture)
(1) The AO-OTA Comprehensive Long Bone Classification
(A) extra-articular fractures
occur in the metaphysis or epiphysis
(B) partial articular fractures
involve only a portion of the articular surface (case1)
(C) complex articular fractures
the articular surface is dissociated completely from the diaphyses so that there is no continuity between any articular piece and the diaphysis
(2) The Schatzker classification: divided into low-energy variants (types I –III) and high-energy variants (types IV–VI)
- Schatzker type I: The fracture line typically occurs in the sagittal plane.
- Schatzker type II: This split depression fracture of the lateral tibial condyle. The cancellous bone underlying the articular surface cannot withstand the load of the lateral femoral condyle and thus sustains a depressed articular region as well as the split component(
P5, case1)
- Schatzker type III: a pure depression fracture of the lateral plateau commonly diagnosed in the elderly and can be considered a fragility fracture. There is no associated metaphyseal condylar fracture line.
- Schatzker type IV: fractures of the medial condyle may not violate the medial articular surface, typically pass more laterally, through or lateral to the intercondylar eminence, and separate the medial plateau from the remainder of the tibia.
- Schatzker type V: total articular fracture in the configuration of an inverted “Y,” with both plateaus separated from each other and from the distal tibia.The nonarticular intercondylar eminence region remains largely intact.
- Schatzker type VI: bicondylar fracture that involves both medial and lateral tibial plateaus, but has the distinction of having more comminution and obvious complete separation of the articular surface (including the eminence) from the diaphysis
2.
脛骨骨幹骨折(Tibial shaft fractures)
3.
遠端脛骨骨折(Distal tibial and medial malleolus fractures)

常見的長骨骨折型態(Long bone fracture) (AO foundation classification)
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解剖

1.
脛骨是全身最主要承受重量的下肢骨。其上以tibial plateau形成膝關節的下界,承受膝蓋以上來的力量;其下以distance to the distal tibia形成medial malleolus,和ankle一起承受全身百分之五十的力量。而tibial tuberosity是許多肌腱的附著點。
2.
在近端,tibialfibulainterosseous membraneanterior and posterior ligaments形成強力的鍵結,形成一個滑液關節(synovial joint)。在遠端,interosseous membrane和三條韌帶anterior, posterior, and transverse tibiofibular ligaments 形成穩固的踝關節。
3.
肌肉、血管、和神經系統在小腿上藉由不同的fascial 包圍成不同的compartments (anterior, posterior, and deep posterior compartments)都會因為tibial或是fibula的受傷而壓迫到不同的腔室而有不同的症狀出現。
4.
anteriordeep posterior compartments來說,造成這兩個腔室的腫大容易產生神經血管壓迫的症狀(neurovascular compromise)Periosteal vesselsnutrient arteries是脛骨最主要的血流供應來源。nutrient arteries最主要來自posterior tibial artery,此處骨折,將造成整隻tibial 的血流供應不佳。

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檢查

1. Deformity(
變形):受傷的腳出現localized swellingshortingangulation
2. Skin integrity(
皮膚外觀)
(1)
挫傷 (contusions)、瘀傷(ecchymosis)
(2)
撕裂傷 (lacerations)
(3)
穿刺傷(puncture wounds) secondary infection
(4)
骨頭碎片突出,形成複雜性骨折(compound fracture)
3.
神經血管完整性:脛骨骨折可能直接傷害神神經血管構造,適當的檢查skin sensationdistal pulsemuscle functioncapillary refilling time,可用來評估神經血管的功能。

影像診斷

1. Plain film radiographs
是用來評估tibial shaft fracture最基本的工具,包括了anteroposterior(AP) lateral views
2.
影像必需包括膝蓋到腳踝整個下肢的部份。
3.
藉由Plain film radiographs可用來評估:
(1)
骨折的位置和形式( ex. Transverse, oblique, comminuted)
(2)
錯位(displacement)
(3)
角度(angulation)
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臨床實例

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併發症

1.
深層筋膜(Fascial extensions)以及脛骨腓骨間的骨間膜(interosseous membrane)把小腿分成四個區間:anterior, posterior, lateral, and deep posterior compartments,其中各有肌肉、神經、血管分布。在脛骨骨折時可能會受到直接的傷害。
2.
在近端脛骨骨折時,可能會造成膝部韌帶或半月板(meniscal)的損傷。
3.
脂肪栓塞(Fat emboli)常見於長骨骨折,可發生在任何一種形式的脛骨骨折。
4.
在複雜性骨折,可能會引發急性腔室症候群(acute compartment syndrome)、神經肌肉損傷、或者因為開放性傷口造成的次級感染(secondary infection)
5.
急性腔室症候群(acute compartment syndrome):因為深筋膜收縮或者因骨折出血造成腔室內的壓力上升,可能會直接造成神經肌肉的受損,也會壓迫到血管使遠端組織灌流減少,需要緊急處理(fasciotomy),最嚴重會有截肢後果。

基本處理原則

1.
使用removable plaster(可拆式石膏)、或fiberglass splint(玻璃纖維),固定骨折的部位,減少組織進一步的傷害,特別是神經和血管。
2.
冰敷以減少發炎和腫脹。
3.
抬高患肢。
4.
給予止痛藥。
5.
必要時進一步的手術處理。

參考資料

1. Uptodate: Overview of tibial fractures in adults
2. Uptodate: Tibial shaft fractures in adults
3. Uptodate: Proximal tibial fractures in adults
4. Emil Reif, T. B. Moeller. Pocket Atlas of Radiographic Anatomy(2000)
5. AO foundation: http://www.aofoundation.org/Pages/home.aspx