Converting round tendons to flat tendon constructs: Does the preparation process have an influence on the structural properties?
OBJECTIVE
The structural properties of hamstring tendon grafts were evaluated in a porcine model, after processing it to a flat shape, to better replace or augment anatomic flat structures (e.g. ACL, MPFL or MCL).


METHODS
In this biomechanical study, porcine flexor tendons were used which have a comparable shape to semitendinosus and gracilis tendons. One part of the tendon was prepared to a flat tendon construct by splitting the tendon longitudinally with a knife to half of the diameter of the tendon. The semi-split tendon was scratched out to a flat shape. The other matched part was tested in its original round shape. The tendons (n = 40) have been fixed in a uniaxial testing machine (Zwick/Roell) by cryo-clamps after preparing the fixed ends by 2-0 polyester sutures (2-0 Ethibond®EXCEL, Ethicon, Somerville, NJ). In every specimen, there was a free 60-mm tendon part between both clamps. The tendons have been loaded to failure to evaluate typical biomechanical parameters such as stiffness, yield load and maximum load.


RESULTS
No statistically significant differences (n.s.) regarding stiffness, yield load and maximum load between natively round and processed flat tendons could be detected.


CONCLUSIONS
A prepared flat-shaped tendon does not show any different structural properties compared with an original round tendon. Therefore, a flat tendon seems to be a biomechanical stable graft option for anatomic reconstruction or augmentation of injured natively flat-shaped structures such as MCL, MPFL or ACL.
Department of Trauma, Hand and Reconstructive Surgery, Westphalian Wilhelms University Muenster, Waldeyer Strasse 1, 48149, Muenster, Germany.
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Domnick
Department of Trauma, Hand and Reconstructive Surgery, Westphalian Wilhelms University Muenster, Waldeyer Strasse 1, 48149, Muenster, Germany. Mirco.Herbort@ukmuenster.de.
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Herbort
Department of Trauma, Hand and Reconstructive Surgery, Westphalian Wilhelms University Muenster, Waldeyer Strasse 1, 48149, Muenster, Germany.
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Raschke
Department of Trauma, Hand and Reconstructive Surgery, Westphalian Wilhelms University Muenster, Waldeyer Strasse 1, 48149, Muenster, Germany.
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Schliemann
HKF - Center for Hip-Knee-Foot Surgery, ATOS Hospital, Bismarckstr. 9-15, 69115, Heidelberg, Germany.|Institute for Anatomy and Cell Biology, INF, Ruprecht-Karls University, Heidelberg, Germany.
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Siebold
Carolina Medical Center, Pory 78, 02-757, Warsaw, Poland.
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Śmigielski
Gelenkpunkt - Center for Sports and Joint Surgery, Innsbruck, Austria.|Research Unit for Orthopaedic Sports Medicine and Injury Prevention, UMIT/ISAG, Hall in Tirol, Austria.
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Fink
D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery; D001178:Arthroplasty / Q000379:methods*; D001696:Biomechanical Phenomena; D002102:Cadaver; D006801:Humans; D011091:Polyesters; D013537:Sutures; D013552:Swine; D013710:Tendons / Q000502:physiology / Q000637:transplantation*; D016474:Weight-Bearing
D011091:Polyesters
Anterior cruciate ligament; Anterior cruciate ligament reconstruction; Biomechanics; Flat tendon; Ribbon