自行車踩踏時膝關節肌肉與韌帶之交互作用:有無阻力之影響

Abstract

踩踏自行車被視為韌帶損傷手術後患者之一溫和復健方法，其不僅可以幫助患者訓練膝關節周邊肌群，亦可避免韌帶負荷過大。而踩踏阻力是在騎行期間改變關節負荷和肌肉活動的最重要的調節因素，藉由阻力調控可以使得膝關節內部軟骨及各條韌帶之負荷不同。 考量侵入式量測的諸多限制，有限元素法被大量應用在非侵入式量測活體膝關節軟組織力學的研究。幾何模型、材料參數、邊界條件為有限元素分析的三大主軸。本研究所使用之每個活體膝關節模型乃客製化模型，其幾何外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膝關節量測實驗和文獻的結果；邊界條件為每位受試者動態X光量測之膝關節骨頭相對的運動學資訊。而本研究將改良實驗式過去研究之有限元素韌帶模型，將之運用在活體自行車運動實驗下，探討有無阻力下膝關節韌帶與軟骨之負荷情形，並進一步利用踏板力規資訊，計算出肌肉力量，以評估韌帶、軟骨和肌肉間的交互作用，提供未來膝關節軟組織力學分析基礎之應用。 根據本研究分析結果，於整個踩踏過程中，無論是有阻力或是無阻力踩踏，對前十字韌帶的負荷皆遠小於韌帶重建後之破壞極限，然而後十字韌帶的負荷與股四頭肌收縮趨勢相符，且大於重建過後所能承受之極限，而軟骨面於踩踏過程中有2個負荷峰值，分別為腓腸肌及股四頭肌收縮時，且內側軟骨受力較外側大，其最大受力約為體重之3-4倍。 由復健的角度來看，建議前十字韌帶損傷/重建，且無後十字韌帶損傷的患者進行有阻力之自行車踩踏。對於後十字韌帶受傷及重建的患者則不建議使用自行車進行復健療程；而對於有膝關節炎的患者則建議使用無阻力之自行車運動作為復健，且盡量調整姿勢使得膝關節避免彎曲過大。

Improper riding posture may cause musculoskeletal system damage, especially on knee-related injuries. However, cycling is also regarded as a gentle rehabilitation exercise for patients with ligament injury or surgery. It not only helps the patient to train the muscles but also avoids excessive ligament load. Cycling with different resistance is the most important factor for soft tissue loading and muscle activity of knee joint. Due to the development of computer technology and the limitations of invasive measurement, the finite element method has been widely used to achieve non-invasive measurement of in vivo joint soft tissue mechanics. The construction of finite element analysis is based on model geometry, material properties and boundary conditions. In the study, the geometry model was obtained from the three-dimensional reconstruction of the computer tomography and magnetic resonance imaging scan. Material parameters of ligaments and the cartilage referred to the KT-2000 arthrometer and literatures. Boundary conditions were acquired from the dynamic fluoroscopy system. According to the results, the load on the anterior cruciate ligament was much less than the damage limit after the reconstruction during both resisted and non-resisted pedaling. However, the load of the posterior cruciate ligament was consistent with the contraction trend of the quadriceps muscle, and was greater than the limit that can be withstood after reconstruction. There were two load peaks of cartilage during pedaling, which were the moment of gastrocnemius and quadriceps contraction. The load of the medial cartilage was higher than lateral’s, and its maximum force was about 3-4 times of the body weight. From the view of rehabilitation, it is recommended that patients with anterior cruciate ligament injury/reconstruction and without posterior cruciate ligament perform pedaling with resistance, which can train muscle more effectively. For patients with posterior cruciate ligament injuries, it is not recommended to use pedaling as rehabilitative treatment. For patients with knee arthritis, it is recommended to pedal without resistance and avoids excessive bending of knee joint.