阿基里氏肌腱修補手術後健患腳小腿三頭肌形態力學差異

Abstract

研究背景：阿基里氏肌腱斷裂常以手術進行修補，已知術後一年健患兩腳的肌力與運動表現仍具差異，例如平衡、跳躍、耐力等。在肌腱癒合過程中，肌束形態及腱性組織機械特性亦可能有所改變，但鮮有文獻探討以上參數在阿基里氏肌腱斷裂術後健患腳之差異，以及與功能性運動表現的關連性。研究目的：本研究將探討阿基里氏肌腱修補手術後一年內，健患兩腳靜態與動態的肌肉肌腱形態學及腱性組織力學特徵、功能性運動表現、自覺嚴重程度、神經肌肉特徵，另探討以上參數之間的相關性，本研究簡稱腱性組織機械特性和肌肉肌腱形態為形態力學，以研究兩者之交互作用。設計：本研究為橫斷式實驗。實驗對象：預計徵召單側阿基里氏肌腱修補手術後3至12個月之患者，年齡介於20至60歲，過去半年內沒有任何下肢傷害，且無任何系統性疾病。方法：受試者於阿基里氏肌腱修補手術後3至12個月的期間接受一次檢測，包含休息狀態、向心及離心蹠屈收縮之下小腿肌肉之肌束形態，等長收縮之腱性組織力學特性，功能性運動表現以及肌電圖數值。統計分析：本實驗採用魏克森符號等級檢定法比較健患兩腳的形態力學、功能性運動表現及肌電圖數值差異，並使用斯皮爾曼等級相關係數分析形態力學與功能性運動表現之相關性。結果：形態學方面，患側的靜態肌肉厚度顯著較薄、肌束和肌肉長度顯著較短、肌腱和腱性組織長度顯著較長（p<0.001~0.049），患側動態之下的肌束長度顯著較短、肌束夾角顯著較大、腱性組織長度顯著較長（p<0.001~0.044），肌束長度、肌肉肌腱單位長度與腱性組織長度的變化量顯著小於健側（p<0.001~0.001）；力學特性方面，術後患側的內側腓腸肌深層腱膜剛性顯著小於健側（p=0.003）；功能性表現方面，患側的前向星狀距離平衡測試、單腳前跳距離、抬腳跟高度、抬腳跟次數和抬腳跟數值均顯著降低（p<0.001~0.028）；肌電圖方面，向心和離心動作之下，術後患側的脛前肌和比目魚肌活化程度均顯著高於健側（p=0.002~0.049），等長收縮動作中，僅脛前肌活化程度顯著高於健側（p=0.040），且健患兩腳肌肉之間的活化程度比值也有顯著差異（p=0.002~0.035）。另外，形態學方面，術後肌肉厚度和肌束長度與最大抬腳跟高度、抬腳跟次數和抬腳跟數值等有顯著正相關性，且肌肉厚度與單腳前跳距離有顯著正相關性；力學特性方面，內側腓腸肌深層腱膜剛性與最大抬腳跟高度及單腳前跳距離有顯著正相關性。結論：阿基里氏肌腱在修補手術後一年內健患兩腳肌束形態、腱性組織力學特性、功能性運動表現及肌電圖數值有顯著差異，且功能性運動表現和肌束形態、腱性組織力學特性具有相關性，因此建議術後應增加高強度訓練和動態訓練，以改善肌肉肌腱形態學及腱性組織力學特徵，促進患者術後復原狀況及運動表現。

Background: The Achilles tendon rupture is often treated by surgical repair. During the healing process, there are changes of the mechanical properties of tendon and morphologies of muscle fascicle that may be associated with functional outcomes after the surgical repairs. Few studies have demonstrated there are adaptations of the muscle morphologies, mechanical properties of tendinous tissue and neuromuscular characteristics within muscles of an injured Achilles tendon, and determined associations between these morphomechanical factors and functional outcomes after the repair. Purpose: The aim of this study is to investigate the differences and the correlations between the mechanical properties of deep aponeurosis, muscle-tendon morphologies, functional performance, and electromyography of triceps surae. Morphomechanics is used to represent muscle fascicle morphologies and tendinous tissue mechanical properties, also the relationship between them. Design: This study is a cross-sectional study. Participants: The study recruited patients who received unilateral Achilles tendon repair within 1 year, and aged between 20 and 60 years old without a systemic disease. Methods: The participants received bilateral measurements of muscle fascicle morphologies during resting, concentric and eccentric plantarflexion and mechanical properties of tendinous tissue during isometric plantarflexion, functional outcomes and electromyography. Statistical analysis: Wilcoxson signed-rank test is used to compare the differences between injured and uninjured leg. Spearman correlation analysis is used to analysis the relationship between variables. Results: In morphology, injured leg had significantly thinner muscle thickness, shorter fascicle and muscle length and longer tendon and tendinous tissue length than healthy leg in resting (p<0.001~0.049). Also, injured leg had significantly shorter fascicle length, larger fascicle angle and longer tendinous tissue than healthy leg during dynamic plantarflexion (p<0.001~0.044). The fascicle, muscle-tendon unit, and tendinous tissue length during dynamic movement showed lower variation in injured leg (p<0.001~0.001). In mechanics, injured leg had significantly lower stiffness of medial gastrocnemius deep aponeurosis (p=0.003). In functional performance, injured leg had significantly shorter balance reach distance, shorter one leg hopping distance, lower heel rise height, less heel rise repetition and lower heel rise index than healthy leg (p<0.001~0.028). In electromyography, injured leg had significantly higher muscle activation in tibialis anterior and soleus muscle than healthy leg during concentric and eccentric plantarflexion (p=0.002~0.049). Tibialis anterior muscle showed significantly higher activation in injured leg during isometric plantarflexion than healthy leg (p=0.040). Muscle co-activation ratio also had significant differences between injured and healthy legs (p=0.002~0.035). Correlation analysis revealed a positive relationship in muscle thickness and fascicle length and heel raise related factor, also in the stiffness of deep aponeurosis and heel raise related factor and one leg hopping distance. Conclusion: The morphomechanics, functional outcome and electromyography changed significantly after Achilles tendon repair within 1 year. Also, functional performance showed correlation with muscle-tendon morphomechanics. Based on our research, we suggest patients after Achilles tendon repair should continue high intensity and dynamic training. We expect the improvement of muscle-tendon morphology and mechanical properties of tendinous tissue in order to restore better exercise performance.