Biomechanical properties of porcine flexor tendon fixation with varying throws and stitch methods.
BACKGROUND
The well-known suture technique configurations used for hamstring tendon autograft preparation in anterior cruciate ligament (ACL) reconstruction are the Krackow locking stitch and nonlocking stitch, such as a baseball stitch and a whipstitch. However, there are few data in the literature regarding biomechanical comparisons of suture techniques.


OBJECTIVE
The purpose of this study was to determine the properties of several current techniques of tendon graft suture employed in ACL reconstruction.


METHODS
Controlled laboratory study.


METHODS
Forty-two fresh-frozen porcine flexor digitorum tendons were used. Three stitch configurations (Krackow stitch [group K], baseball stitch [group B], and whipstitch [group W]) were assessed with varying suture throws (6 throws, group×6; 10 throws, group×10) using No. 5 Ethibond sutures. Each group was tested at 1500 loading cycles between 50 and 200 N. After loading cycles, the surviving tendons underwent a load-to-failure test.


RESULTS
During the loading cycles, 3 of 7 specimens in group B×6 and all specimens in group W×6 failed by suture pullout. Four of 7 specimens in group B×10 and all specimens in group W×10 showed partial tearing of the tendon. Elongation of group B×10 and group W×10 showed significantly greater elongation than other groups (P < .05). Maximum loads at failure showed significant differences between group K and the other groups (K×6, 436 ± 52 N; K×10, 419 ± 34 N; P < .05). Most specimens failed by rupture of the suture thread in group K. Pullout of the suture from the tendon was observed most in groups B and W.


CONCLUSIONS
The Krackow stitch was superior to other stitch methods. There was, however, no significant effect of the number of throws on the holding strength.


CONCLUSIONS
The Krackow stitch could prevent suture slippage by a locking mechanism. The whipstitch is not suitable for clinical application even with an increased number of throws.
Department of Orthopaedic Surgery, Saitama Medical University, 38 Morohongo, Moroyama-machi, Iruma-gun, Saitama, 350-0495, Japan. katsuguchi@msn.com
Katsunobu
K
Sakaguchi
Yomei
Y
Tachibana
Hiromi
H
Oda
D000818:Animals; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001696:Biomechanical Phenomena; D013536:Suture Techniques; D013552:Swine; D013710:Tendons / Q000503:physiopathology* / Q000637:transplantation*; D013718:Tensile Strength