1、應變實際在骨折愈合中的臨床運用一點粗淺的了解2019-03-30骨折愈合的分型應變的概念基于Perren應變實際的一些AO理念附：微動促進骨折愈合的一項研討要點nFracture healing can be divided into two types:nprimary or direct healing by internal remodeling; nsecondary or indirect healing by callus formation n骨折愈合分為2種類型n經過內塑形的一期或直接愈合n經過骨痂構成的二期或間接愈合直接愈合noccurs only with absolute

2、 stability and is a biological process of osteonal bone remodeling n僅發生在絕對穩定固定時，它是骨單位重建的生物過程n絕對穩定使骨折部位的修復組織在生理負荷下的應變完全消除n將應變減少到臨界值以下可以減少骨痂構成的刺激，使骨折的愈合沒有出現肉眼可見的骨痂間接愈合noccurs with relative stability (flexible fixation methods). It is very similar to the process of embryological bone development and in

3、cludes both intramembraneous and endochondral bone formation. In diaphyseal fractures, it is characterized by the formation of callus. n發生于相對穩定固定時彈性固定方法，包括膜內成骨和軟骨成骨n除了加壓技術外，一切的固定方法均可視為彈性固定，提供相對穩定性。n其特點是骨痂構成nBone healing can be divided into four stages:ninflammation; nsoft callus formation; nhard cal

4、lus formation; nremodeling. n骨折間接愈合的四個階段n炎性期n軟骨痂構成期n硬骨痂構成期n重塑形期nInterfragmentary movement stimulates the formation of a callus and accelerates healing n骨痂構成需求一定程度的力學刺激n骨折塊之間的相對活動可刺激骨痂的構成，加速骨折的愈合Perrens strain theorynThe manner in which mechanical factors influence fracture healing is explained by Pe

5、rrens strain theory.nPerren SM, Cordey J (1980) The concept of interfragmentary strain. Berlin Heidelberg New York: Springer-Verlag.nPerren應變實際解釋了機械力學要素對于骨折愈合的影響Perrens strain theory Perren應變實際應變實際nMotion at the fracture results in deformation producing strain in the granulation tissue at the fractu

6、re site.n骨折端的活動引起的形變會在骨折端肉芽組織中產生應變Strain-應變nStrain is the deformation of a material when a given force is applied. nNormal strain is the change in length ( l) in comparison to original length (l)when a given load is applied. Thus, it has no dimensions and is often expressed as a percentage. n在應力作用下，

7、資料在單位長度內發生的形變n對資料施加應力后其長度發生的變化n沒有單位，通常用百分比表示n=L-L。/L。n= L/Ln組織在功能正常形狀下可耐受的變形程度有很大的變化范圍n完好骨骼的正常應變程度為2%骨折發生前n肉芽組織的應變才干為100%n在早期，當骨痂主要成分為軟組織時，骨折端耐受畸形或組織應變的強度要大于后期的骨性骨痂nThe amount of deformation that a tissue can tolerate and still function varies greatly. Intact bone has a normal strain tolerance of 2%

8、 (before it fractures), whereas granulation tissue has a strain tolerance of 100%. nBony bridging between the distal and proximal callus can only occur when local strain (ie, deformation) is less than the forming woven bone can tolerate. nThus, hard callus will not bridge a fracture gap when the mov

9、ement between the fracture ends is too great nThus, overloading of the fracture with too much interfragmentary movement later in the healing process is not well toleratedn只需當部分的應變小于編織骨所能耐受的程度，遠近端的骨痂才干發生骨性銜接n因此，當骨折端的活動過大時，硬骨痂無法橋接骨折端n在骨折愈合的后期，過度的負荷使骨折塊發生過多的活動不利于骨折的愈合nCallus formation will not take pla

10、ce when the strain is too low nA low-strain environment will be produced if the fixation device is too stiff, or if the fracture gap is too wide . Delayed healing and nonunion will resultn但是，當應變過小時骨痂無法構成n當固定安裝過于鞏固或骨折間隙過寬時，會產生低應變的環境，此時可發生骨折不愈合或延遲愈合根據Perrens strain theorynthe strain is the higher the

11、smaller the gap is.nThe same deforming force produces more strain at the site of a simple fracture than at that of a multifragmentary fracture.n骨折間隙越小，應變越大n一樣的應力作用于簡單骨折和粉碎骨折，其中簡單骨折產生的應變較大nMultifragmentary fractures tolerate more motion between the two main fragments because the overall movement is s

12、hared by several fracture planes, which reduces the tissue strain or deformation at the fracture gap. n粉碎骨折可耐受兩個主要骨折塊之間有更大范圍的活動n由于其總的活動被不同的骨折平面所分擔，因此減少了骨折間隙中組織的應變nA perfectly reduced simple fracture (small gap) stabilized under compression (absolute stability and low strain) heals without external c

13、allus (direct healing). n簡單骨折間隙小解剖復位加壓固定絕對穩定，低應變后，骨折發生無外骨痂的愈合直接愈合nA simple fracture (small gap) fixed with a bridging plate (relative stability) is exposed to movement (high strain). Fracture healing is delayed or will not occur at all n簡單骨折間隙小用橋接鋼板相對穩定固定后，骨折端的活動導致高應變，骨折愈合延遲甚至不愈合nToday there is clin

14、ical experience and experimental proof that flexible fixation can stimulate callus formation, thereby accelerating fracture healing . nThis can be observed in diaphyseal fractures splinted by intramedullary nails, external fixators, or bridging plates n已有臨床和實驗室證聽闡明彈性固定可刺激骨痂的構成，從而促進骨折的愈合n骨干骨折后，運用隨內釘、

15、外固定架、橋接鋼板固定可察看到這一景象nIn a complex fracture (large gap) fixed with a bridging plate (relative stability) the strain will be low in spite of movement, and fracture healing will occur with callus formation (indirect bone healing). n復雜骨折間隙大用橋接鋼板相對穩定固定后，骨折端雖有活動，但應變低，骨折發生有骨痂構成的愈合間接愈合外部機械刺激對運用彈性外固定固定的骨干截骨模型

16、愈協作用的研討BackgroundnIt is generally accepted that small interfragmentary movements (IFMs) yield better bone healing results than larger IFMs ( 1 mm). nHowever, the optimal size of IFM within the l-mm range remains undetermined.ObjectivenThe purpose of this study was to investigate the effect of an ext

17、ernally applied mechanical stimulus on fracture healing under flexible fixation.DesignnStimulation of fracture healing under various conditions of interfragmentary movement in an in vivo fracture model on 41 sheepMethodsnStandardized transverse osteotomy of 3 mm gap size in the left ovine tibia was

18、fixed with an unilateral external fixator. nTo perform controlled axial micromovement, a custom-designed stimulation module was applied to the fixator rods (Fig. 1). The module was electromechanically driven and controlled by a microprocessor .MethodsnThe sheep were divided into four IFM groups of 0.0, 0.2, 0.4 and 0.8 mmn and stimulated with this amplitude振幅 for 1200 cycles per day at 1 Hz. nExterna