Estimation of the mechanical property of meniscus using ultrasound: examinations of native meniscus and effects of enzymatic digestion.
We previously developed a novel ultrasound assessment system featuring wavelet transform to evaluate the material properties of articular cartilage. We aimed in this study to demonstrate the feasibility of quantitative evaluation of meniscus using ultrasound and to elucidate the relationships between its acoustic, mechanical, and biochemical properties. Meniscal disc specimens from mature pigs were assessed by ultrasound and compression testing, and their correlation was analyzed. A positive correlation was found between the ultrasound signal intensity and apparent Young's modulus (r=0.61). Subsequently, the porcine meniscal discs were treated with various enzymes and then characterized by ultrasound, by compression tests, by biochemical analyses, and by histology and immunohistochemistry. The signal intensity was decreased not by hyaluronidase but by collagenase treatment. Hyaluronidase-treated menisci showed a discrepancy between acoustic and mechanical properties, suggesting that the ultrasound reflection could not detect a reduction in proteoglycan content. Also, ultrasound signal intensity could only reflect superficial layers of the material. Several limitations exist at present, and further studies and improvements of the device are required. However, given the noninvasive nature and the requirement of only small equipment, this ultrasound assessment system will be an instrumental diagnostic tool for meniscal function in both research and clinical fields.
Yasura
Ko
K
Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Mizuno
Yasuyuki
Y
Nakagawa
Yasuaki
Y
Mori
Koji
K
Takenaka
Makoto
M
Ohashi
Tetsuo
T
Yamada
Keisuke
K
Kobayashi
Masahiko
M
Ando
Keiji
K
Kuroki
Hiroshi
H
Suzuki
Takashi
T
Ikeuchi
Ken
K
Tsutsumi
Sadami
S
Nakamura
Takashi
T
D000818:Animals; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000187:drug effects / Q000502:physiology*; D017364:Collagenases / Q000494:pharmacology; D019245:Compressive Strength / Q000187:drug effects / Q000502:physiology; D006025:Glycosaminoglycans / Q000378:metabolism; D006821:Hyaluronoglucosaminidase / Q000494:pharmacology; D006909:Hydroxyproline / Q000378:metabolism; D008592:Menisci, Tibial / Q000000981:diagnostic imaging / Q000187:drug effects / Q000502:physiology*; D012212:Rheology / Q000379:methods; D013552:Swine; D014465:Ultrasonics; D014463:Ultrasonography; D014867:Water / Q000378:metabolism
D006025:Glycosaminoglycans; D014867:Water; D006821:Hyaluronoglucosaminidase; D017364:Collagenases; D006909:Hydroxyproline