肩關節旋轉肌撕裂是常見的肩部疾病，透過骨錨釘及手術縫線能夠將斷裂的肌腱做修復，多孔結構骨錨釘可以促進骨長入效果。然而多孔結構的骨錨釘本身機械強度不如實體結構骨錨釘，因此在設計多孔結構的骨錨釘須了解用於治療旋轉肌撕裂的固定強度。而可降解材料的使用可以解決患者需要進行二次手術的需求，但是骨錨釘經過降解後其植體強度是否滿足人體需求是需要探討的。在過去的研究可以透過電腦分析技術的方式探討骨錨釘的固定強度，然而模型的建立並未考慮手術縫線的施加。可降解植體透過降解實驗了解機械性質的變化需要花費大量的時間，對於可降解植體的開發是一限制。因此本研究的目的為建立包含手術縫線的可降解鐵基骨錨釘拔出模型，以及利用數位雕刻建模技術建置鐵基骨錨釘降解模型，探討鐵基骨錨釘的固定強度及降解後的機械性質變化。
本研究針對兩種結構設計鐵基骨錨釘進行研究，建立骨錨釘拔出模型，針對三種手術縫線牽引角度0度、45度及90度，進行拔出模擬探討鐵基骨錨釘在不同拔出角度下的固定強度。而鐵基骨錨釘降解後的幾何外型透過數位雕刻建模技術，分別建置了五種降解情況的實體幾何模型，並透過拉伸模擬計算鐵基骨錨釘的機械性質變化。
電腦模擬結果顯示，鐵基骨錨釘的可撓性結構可以在45度角拔出及90度角拔出增加骨錨釘的固定強度。透過數位雕刻建模技術可以有效的建置鐵基骨錨釘降解模型，並且計算出的機械性質變化趨勢與機械測試資料相同。本研究建置的鐵基骨錨釘電腦模擬分析技術預期能夠給予骨錨釘的開發設計提供幫助。

Rotator muscle tear is a common shoulder disease. Bone anchors and sutures can be used to repair the ruptured tendon. Porous structure bone anchor can promote bone ingrowth effect. However, the mechanical strength of bone anchors with porous structures is worse than that of solid-structure bone anchors. Therefore, in the design of bone anchors with porous structures, it is necessary to understand the fixation strength for the treatment of rotator tears. The use of biodegradable materials can address the need for secondary surgeries in patients. However, it is necessary to investigate whether the implant strength of bone anchors meets the requirements of the human body after degradation. Past studies have studied the fixation strength of bone anchors through finite element analysis. However, the numerical models did not consider sutures. Evaluating the mechanical properties of biodegradable implants through degradation experiments requires a significant amount of time, which poses limitations in the development of biodegradable implants. Therefore, the aim of this study was to establish an iron-based bone anchor pullout model and degradation model that incorporates finite element analysis and digital sculpting modeling techniques.
A pullout model for the two designs of bone anchors was developed to simulate the fixation strength under three different angles of suture traction: 0 degrees, 45 degrees, and 90 degrees. Furthermore, the iron-based bone anchors after degradation were constructed using digital sculpting modeling techniques. Five different degradation periods of bone anchors were developed, and the mechanical property changes of the iron-based bone anchors were calculated through tensile simulations.
The computer simulation results showed that the flexible structure of the iron-based bone anchor can increase the fixation strength during pullout at 45 degrees and 90 degrees angles. The use of digital sculpting modeling techniques effectively facilitates the construction of degradation models for iron-based bone anchors, and the calculated trends in mechanical property changes align with the mechanical testing data. The computer simulation analysis technique for iron-based bone anchors developed in this study was expected to provide assistance in the design and development of bone anchors.

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