自行車踩踏方向對膝關節韌帶與關節面負荷之影響

Abstract

自行車除了具有交通運輸、休閒以及運動健身等功能，更被廣泛應用於下肢傷害的復健，而復健療程依據踩踏方向可分為前踩式和後踩式運動。膝關節是下肢運動使用率最高的關節，除了肌肉自主收縮的控制外，韌帶與軟骨在不同運動狀態中各是扮演對關節穩定性的重要角色，因此關節軟組織的傷害是相當常見的，特別是膝關節十字韌帶損傷。 由於電腦技術的快速發展，考量侵入式量測的諸多限制，有限元素法被大量應用在實現非侵入式量測活體膝關節軟組織力學的研究。有限元素分析的建構分別以幾何模型、材料參數、邊界條件為三大主軸。客製化活體膝關節的幾何模型來自電腦斷層掃描和核磁共振造影的三維影像重建，韌帶與軟骨的材料參數分別參照KT-2000膝關節穩定器量測實驗和文獻的結果，邊界條件為動態X光量測之膝關節骨頭相對的運動學資訊。改良驗證過的有限元素分析流程，運用在活體自行車運動實驗下，探討前後踩踏方向下膝關節韌帶與軟骨之負荷情形，並提供未來膝關節複雜軟組織力學分析基礎之應用。 根據本研究分析結果，在自行車運動中，軟組織主要負荷代表為後十字韌帶與內側軟骨面。韌帶負荷的分佈在膝關節伸直期遞減，膝關節彎曲期遞增；軟骨面負荷的分佈有三個負荷峰值發生(曲柄角度45度、135度和280度)，最大接觸負荷為體重的2 ~ 4倍。前後踩踏方向對韌帶負荷值影響有限；對軟骨面負荷值的影響為後踩踏在膝關節伸直期需要較多軟骨面之貢獻，而彎曲期不如前踩踏需要軟骨面之貢獻。由臨床角度來看，建議前十字韌帶損傷患者早期先以後踩踏方式進行復健；建議軟骨面損傷患者早期先以後踩踏方式進行復健；另外，不建議後十字韌帶損傷患者使用自行車運動作為復健療程。

Cycling has many functionality in our daily life. It is also widely applied to the rehabilitation of the lower extremities, and it can be classified according to the pedaling direction as forward pedaling and backward pedaling. The knee ligaments and articular cartilages has a great influence on the knee joint stability. Because of the highest utilization rate, knee injuries with soft tissues is common, especially cruciate ligament injuries. Finite element method is used to study in vivo joint soft tissue mechanics in the non-invasive measurement. The geometry model is from the three-dimensional reconstruction of the computer tomography and magnetic resonance imaging scan. Material parameters of soft tissues referred the KT-2000 arthrometer and literatures. Boundary condition is acquired from the dynamic fluoroscopy system. The objective of this study was to analysis the loading of the in vivo knee ligaments and articular cartilages in forward and backward pedaling with validated finite element analysis procedure. It will provide a mechanical analysis basis of knee complicated soft tissues in the future. According to the finite element analysis results in cycling, the main representative of the loads in soft tissues were PCL and the medial cartilage. The ligament loads decline in the knee extension and increase in the knee flexion. The articular surface loads show three peak loads (crank angle of 45°, 135° and 280°) and the maximum contact load is 2 ~ 4 times body weight. The effect on pedaling direction is less on the ligament loading. In backward pedaling, it needs more articular surface loading in knee extension and less in knee flexion. In early rehabilitation treatment, the patients with ACL injury and the patients with cartilage damage are suitable for backward pedaling. Cycling is not appropriate for PCL injury patients.