近端肱骨骨折相當常見，但是對於其中肱骨粗隆骨折的了解較少。肱骨粗隆骨折手術治療時若能有牢靠的固定，對於術後的骨折癒合及後續的復健療程會有很大的幫助，可以加快病人的復原速度。縫合錨釘(suture anchor)及螺絲(screw)已經被廣泛運用在肱骨粗隆骨折的固定，但對於此兩種固定材料在不同固定結構之生物力學研究仍然十分缺乏，為了更加了解肱骨粗隆骨折不同手術固定方式的優缺點，探討相關固定結構的生物力學強度表現，是瞭解及增加手術治療成功重要的一環。
本研究共分成三個部份，本研究的第一部份為利用肩關節大體模型，分析利用縫合錨釘(suture anchor)或螺絲(screw)來固定肱骨粗隆骨折時，常使用的三種不同固定結構 Double-Row Suture Anchor Fixation (DR); Suture-Bridge Technique using suture anchors and knotless suture anchors (SB); Two-Screw Fixation (TS) 的生物力學強度，研究結果顯示使用縫合錨釘的固定方式(DR及SB)不管在產生3或5毫米位移的力量以及肱骨骨折的最終破壞載荷的力學表現都較使用螺絲的固定方式(TS)為佳。本研究的第二部份將利用豬的肩關節模型，使用與前述相同縫合錨釘或螺絲的三種不同固定技術，探討在不同的肩關節外展角度下，對於肱骨粗隆骨折固定強度是否產生影響。我們發現DR組在肩關節低外展角度時具有最大的初始固定強度，而SB組在高外展角度具有最好的初始固定強度， TS組的力學強度則不受外展角影響。
基於前述的研究結果，我們發現肱骨粗隆骨折使用縫合錨釘的固定方式，在生物力學強度上較使用螺絲的固定方式更好。但使用縫合錨釘結構的骨折界面接觸性質目前尚未被闡明，因此本研究的第三部份將利用介面壓力感測裝置，分析及比較常用的兩種縫合錨釘雙排固定結構(DR和SB)在骨折介面的壓力情況。結果顯示，儘管SB結構在固定後一開始具有較佳的界面接觸壓力，但在給予骨折塊施加100N拉力後，DR構造在各個外展角度下都有更好的接觸壓力表現。本研究之成果讓我們清楚瞭解肱骨粗隆骨折在不同手術固定方式下的生物力學強度，讓我們對於利用縫合錨釘及螺絲來固定肱骨粗隆骨折時，在不同的固定結構及不同的肩關節外展角度下，對於強度和介面壓力的影響有更進一步的認知，也幫助骨科醫師未來在治療肱骨粗隆骨折時，有更多參考的資訊及相關的實證醫學資料。

Despite the common occurrence of the proximal humeral fracture, the subgroup of isolated greater tuberosity fracture remains less understood. Firm fixation of the greater tuberosity fragment to the humerus is an important factor in initial fracture healing and allows for subsequent rehabilitation. Suture anchors and screws are commonly used in either arthroscopic or open surgeries for the fixation of the greater tuberosity fracture, but no biomechanical studies have been performed to compare the strength of fixation constructs using these two implants. The understanding of the fixation strength and surgical strategies based on biomechanical perspectives is indispensable.
Therefore, there are three scopes in this study. The first purpose is to analyze the strength of three different fixation constructs, using suture anchors or screws, for the management of greater tuberosity fractures in a human cadaveric model. The three configurations are Double-Row Suture Anchor Fixation (DR); Suture-Bridge Technique using suture anchors and knotless suture anchors (SB); and Two-Screw Fixation (TS). The results suggested that the suture anchor constructs would be stronger than the fixation construct using screws in the forces that create 3- and 5-mm displacements and the ultimate failure load for the humeral greater tuberosity fracture.
The second purpose is to investigate the effects of shoulder abduction on the fixation of a humeral greater tuberosity fracture among three common configurations using suture anchors or screws in a porcine model. The three fixation techniques as described above were used for the biomechanical comparison. We found that the DR group had greatest initial fixation strength at a low abduction angle, whereas the SB group had the highest initial fixation strength at a high abduction angle. The TS group appeared unaffected by the abduction angle.
Based on our previous results, suture anchor-based fixation has better results in biomechanical strength than screw-based construct for the management of greater tuberosity fracture. We compare the contact characteristics of two double-row suture anchor fixations (DR and SB) since the interface contact properties of these fixation constructs have not been elucidated. Findings suggest that despite the SB construct having superior interface contact pressure initially after fixation, the DR construct provided better contact performance at all abduction angles with the applied force (100N). The results help us understand the biomechanical properties of different fixation constructs for greater tuberosity fractures as well as whether the shoulder abduction position affects the biomechanical strength of the fixation constructs. This study may provide useful information for assisting the orthopedic surgeons to make the decisions regarding the optimal treatment for patients with humeral greater tuberosity fractures.

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