以超音波評估正常及受傷後十字韌帶之自然頻率

Abstract

韌帶發炎是運動傷害常見的問 題，髕骨韌帶炎的診斷，除了臨床的 評估外，大部分是利用超音波或核磁 共振檢查，但這些檢查只提供了形態 學上的診斷，而無法瞭解韌帶的物理 特性，例如是否鬆弛。本研究的目的 在於找出正常髕骨韌帶是否有自然頻 率（或共振頻率）的存在，於病變時 共振頻率是否改變。 10 名健康受試者參與本研究，首 先將振動源固定於受試者之脛骨內 側，加速規貼於髕骨韌帶上，振動源 提供不同頻率之振動，而加速規測量 不同頻率下髕骨韌帶之振幅大小，受 試者於膝關節伸直，彎曲60 度，彎曲 90 度各測量一次，結果顯示在膝關節 伸直時，在22.5 ± 0.8 Hz 產生髕骨韌 帶之共振頻率，膝彎曲60 度時在23.0 ± 0.7 Hz 產生共振頻率，在膝關節彎曲 90 度時，在24.0 ± 0.8 Hz 產生共振頻 率，利用paired t test 發現當膝蓋彎曲 角度增加（即髕骨韌帶張力增加）時， 髕骨韌帶之自然頻率統計上有意義的 變高( P < 0.05 )，但比較左右膝之髕骨 韌帶之自然頻率則無統計差異存 在。在7 名有病變之髕骨韌帶檢查並 未發現其共振頻率和正常側不同。

Tendinitis is a common problem of athletes. Ultrasonography and Magnetic Resonance Imaging study are taken as the standard method to detect the pathology of tendinitis. However, they only provide the morphology information, and lacking of the physical characteristics. The purpose of this study attempts to define the nature frequency (resonance frequency) of patellar tendon in normal subjects, and detect the change of nature frequency in injuried patellar tendon. Ten healthy normal subjects were included in this study. The vibrator, providing a wide range frequency of vibration, was secured on the medial 2 tibia of the subjects. One accelerometer was fixed on the patellar tendon to measure the amplitude of vibration of patellar tendon in different frequency of vibration. The tests were performed at three position of knee joint, representing different tension of the patellar tendon. Those are full extension, flexion 60 degree, and flexion 90 degrees of the knee. The result showed that the patellar tendon, when full extended, produced the greatest vibration at 22.5 + 0.8 Hz, which is the nature frequency. The greatest vibration occurred at 23.0 + 0.7 Hz when knee flexed 60 degrees, and occurred at 24.0 + 0.8 Hz when knee flexed 90 degrees. In addition, the nature frequency of patellar tendon increased significantly when the flexion angles of knee increased. Meanwhile, the right and left legs had the same nature frequency of patellar tendon. There were no frequency change in severe patients with patellar pathology.