Open AccessFour‐strand hamstring graft is stiffer than a tripled semitendinosus graft in anterior cruciate ligament reconstruction: a cadaveric study
Author(s) -
Hagemans Frans J. A.,
Overvest Karlijn L. J.,
Zijl Jacco A. C.,
Meuffels Duncan E.
Publication year - 2020
Publication title -
journal of experimental orthopaedics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 18
ISSN - 2197-1153
DOI - 10.1186/s40634-020-00254-6
Subject(s) - cadaveric spasm , hamstring , anterior cruciate ligament , medicine , clamp , biomechanics , surgery , fixation (population genetics) , significant difference , anatomy , semitendinosus muscle , mechanical engineering , population , clamping , environmental health , engineering
Purpose The aim of this study was to compare the biomechanics of a four‐strand hamstring graft with a tripled semitendinosus graft, with and without adjustable extra‐cortical button fixation, in a cadaveric model. Methods Four groups of 10 cadaveric hamstrings were tested: In group A, a tripled semitendinosus graft fixated with two adjustable extra‐cortical buttons; in Group B, a four‐strand semitendinosus and gracilis graft fixated with an adjustable extra‐cortical button and a clamp; in group C, a tripled semitendinosus graft fixated to a steel hook and a clamp; in group D, a four‐strand semitendinosus and gracilis graft fixated to a steel hook and a clamp. Each group was submitted to a cyclic loading test (1000 cycles between 50 and 250 Newton at a frequency of 0.5 hertz) and a load‐to‐failure test. Primary outcomes were ultimate failure load and stiffness. Secondary outcomes were graft elongation and graft diameter. Results There was no difference in ultimate failure load among groups. Group B achieved a median stiffness of 171 N/mm (interquartile range [IQR] 139–204) which was significantly higher than Group A (median 103 N/mm (74–119), p < 0.01). Group B showed more cyclic elongation (4.1 mm (3.4–5.7)) compared to group D (2.3 mm (1.9–3.0)), and also lower stiffness was noted (171 N/mm (139–204) vs 265 N/mm (227–305)). There was no difference in graft diameter among groups. Conclusions The results of this study indicate that higher stiffness can be achieved using four‐strand hamstring tendon grafts compared to tripled semitendinosus grafts when using femoral extra‐cortical buttons, despite comparable graft diameters. Thereby, the use of adjustable extra‐cortical fixation devices may result in more cyclic elongation and lower stiffness of the graft.