退化性膝關節炎患者步行時下肢之生物力學分析

Abstract

退化性膝關節炎 (osteoarthritis, OA) 是一種退化性的關節疾病，同時罹病率也在族群之中逐漸提高。同時主要好發於膝關節。其中在膝關節內側發生退化現象的比例也要比發生在膝關節外側來的高。 本研究之目的為利用配備有七台紅外線超高頻攝影機之動作分析系統來量測罹患雙邊內側退化性膝關節炎患者在步行時下肢之運動學資料，並利用測力板量測地面反作用力。本研究先建立健康老年人步行之下肢力動學資料，並為此為基礎進一步探討罹患輕微退化性膝關節炎等級患者、嚴重退化性膝關節炎等級患者以及健康老人步行時下肢之生物力學，以了解不同等級之退化性膝關節炎對於步行之影響。結果顯示由於病患之膝關節內側因退化造成的磨耗直接造成膝關節額狀面內收角度增加，使得髖關節及踝關節也會因應膝關節角度的變化而產生代償性之角度改變。而病患呈現增加之髖關節外展肌群力矩使因為膝關節之外展肌群力矩能夠達到接近正常膝關節之範圍，以期達到避免膝關節內側受力增加。 同時我們也利用下肢弳度(stiffness)的觀念，探討罹患退化性膝關節患者在步行之作用力與腳長變化量彼此之關係。結果發現嚴重退化性膝關節炎患者在步態週期中單腳承重期之中，下肢弳度大於健康老人同一特徵點之下肢弳度，其有可能是為了減少身體質量中心在垂直方向之變化而做出的改變，進而增加下肢在步態中期時之穩定度，已彌補因膝關節退化所造成之神經運動功能之缺損。

Osteoarthritis (OA) is one of the common degenerative joint diseases and the prevalence has been increased in the population. The knee is most involved joint of the lower extremity despite the hip and ankle joint may be involved, too. Degenerative changes of knee OA are commonly observed in the medial compartment than in the lateral compartment of the knee. In the present study used the 3-D motion analysis system to acquire the kinematics of the lower extremity of the subjects with bilateral medial knee OA and the forceplates to obtain the ground reaction force data. The kinetics of the normal elderly were be estimated firstly and investigated the biomechanics of the lower extremities in mild knee OA, severe knee OA and normal elderly during level walking. Our results suggested that knee adduction angle of both mild and severe knee OA subjects increased due to the deformation of medial knee of knee OA. The hip joint and ankle joint increased their abduction and adduction to compensate this knee excessive adduction. The mild and severe knee OA subjects both increased hip abductor moment. But only the knee abductor moment of the mild knee OA subjects had no different significantly with the knee abductor moment of normal elderly during stance phase. The concept of global leg stiffness was used to investigate the relationship between ground reaction force and change of leg length. Our result suggested that the global leg stiffness of the severe knee OA subjects represented bigger stiffness than normal elderly significantly during midstance phase and might be due to decrease the trajectory change of COM at vertical direction.