Mechanical properties of intrasynovial and extrasynovial tendon fascicles.
BACKGROUND
Tendon grafting in tendon reconstruction often involves the interchange of intrasynovial and extrasynovial tendons. Although many studies have examined the cellular and biological differences between tendons of various sources, few have studied the mechanical properties of these two different types of tendons. The purpose of this study was to investigate the mechanical properties of intrasynovial and extrasynovial tendons.


METHODS
Canine peroneus longus (extrasynovial) and flexor digitorum profundus (intrasynovial) tendons, further subdivided into intrasynovial tendinous and intrasynovial fibrocartilaginous segments, were used in the study. An indentation test was used to measure the compressive modulus. Tensile testing was performed on 400mum longitudinal sections.


RESULTS
The compressive modulus of the intrasynovial fibrocartilaginous segment was significantly higher than that of the intrasynovial tendinous segment, which was in turn significantly higher than that of the extrasynovial tendon (P<0.0001). The tensile modulus of extrasynovial tendon was significantly higher than that of intrasynovial fibrocartilaginous and intrasynovial tendinous segments (P<0.005). The tensile modulus of the intrasynovial fibrocartilaginous and tendinous segments was not significantly different (P=0.14).


CONCLUSIONS
The results suggest that extrasynovial tendons exhibit superior tensile properties but inferior compressive properties when compared to intrasynovial tendons, which is consistent with their biological role in situ, but which could lead to complications when these tendons are repositioned during tendon graft surgery.
Shin
Richard H
RH
Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
Zhao
Chunfeng
C
Zobitz
Mark E
ME
Amadio
Peter C
PC
An
Kai-Nan
KN
D000704:Analysis of Variance; D000818:Animals; D001696:Biomechanical Phenomena; D019245:Compressive Strength; D004285:Dogs; D006614:Hindlimb; D016059:Range of Motion, Articular / Q000502:physiology; D013583:Synovial Membrane / Q000502:physiology*; D013710:Tendons / Q000502:physiology* / Q000637:transplantation*; D013718:Tensile Strength