Geometry, time-dependent and failure properties of human meniscal attachments

Abstract

Meniscectomies have been shown to lead to osteoarthritis and the success of meniscal replacements remains questionable. It has been suggested that the success of a meniscal replacement is dependent on several factors, one of which is the secure fixation and firm attachment of the replacement to the tibial plateau at the horn locations. To aid in the development of meniscal replacements, the objectives of the current study were to determine the time-dependent and failure properties of human meniscal attachments. In contrast to the time-dependent tests, during uniaxial failure testing a charge-coupled video camera was used to document the local strain and linear modulus distribution across the surface of the attachments. The lateral attachments were statistically smaller in cross-sectional area and longer than the medial attachments. The anterior attachments were statistically longer and had a smaller cross-sectional area than the posterior attachments. From the stress relaxation tests, the load and stress relaxation rates of the medial anterior attachment were statistically greater than the medial posterior attachment. There were no significant differences in the creep, structural properties or the ultimate stress between the different attachments. Ultimate strain varied between attachments as well as along the length of the attachment. Ultimate strain in the meniscus region (10.4±6.9%) and midsubstance region (12.7±16.4%) was smaller than the bony insertion region (32.2±21.5%). The lateral and anterior attachments were also found to have statistically greater strain than the medial and posterior attachments, respectively. The linear modulus was statistically weaker in the bony insertion region (69.7±33.7 MPa) compared to the meniscus region (153±123 MPa) and mid-substance region (195±121 MPa). Overall the anterior attachments (169±130 MPa) were also found to be statistically stronger than the posterior attachments (90.8±64.9 MPa). These results can be used to help design tissue engineered replacement menisci and their insertions and show the differences in material properties between attachment as well as within an attachment.

Structural Properties of the Meniscal Roots

“…In the 2 previous studies noted. 9,18 the authors did not control for age or sex with their specimens, which may explain, at least in part, the differences between the 2 studies. Interestingly, differences in ultimate failure strengths between the 4 roots may be related to mobility differences within the menisci themselves.…”

“…Hauch et al 9 were the first to compare the stiffness of the meniscal roots. Just as in our study, they reported the highest stiffness for the AL root (219 N); however, they reported that the PL root had the lowest stiffness (130 N), 9 as compared with the PM root in our study.…”

Die anterioren meniskotibialen Ligamente

“…Nach Messung der Querschnittsfläche konnten sie den Elastizitätsmodul der Bänder bestimmen, welcher zwischen 150 und 300 MPa betrug. Im Anschluss an diese Arbeit wurden dieselben Versuche an humanen Verankerungsligamenten vorgenommen [8]. Dabei wurden signifikante Unterschiede zwischen den anterioren und posterioren, sowie den lateralen und medialen Bändern aufgezeigt.…”

“…Tab. 3; [6,8,21,25]). Es scheint, dass die mechanische Kompetenz der Bänder mit ihrem geometrischen Querschnitt korreliert, was bisher jedoch in der Literatur noch nicht bestätigt werden konnte.…”

Development and Validation of a Tibiofemoral Joint Finite Element Model and Subsequent Gait Analysis of Intact ACL and ACL Deficient Individuals

“…The spring used was type "SPRINGA" which strictly uses the change in length in the spring between the initial and deformed configurations to determine the spring displacement. The stiffness's of the springs used in each attachment horn were taking from published data of the attachment horn's stiffness [87], shown in Table 7. The rest of the nodes on the meniscal attachment face were tied to the central node using a kinematic coupling constraint.…”