Cyclic‐loading of the Human Gracilis and Semitendinosus Muscle Tendons: Study of Young Adult Cadavers

Abstract

During knee ligament reconstruction, the tendon graft is tensioned to prevent the occurrence of excessive graft elongation during the postoperative period. Tensioning may be achieved by applying a cyclic or static load to the graft during fixation. Although this procedure is part of the surgery, there is no consensus in international literature regarding ideal tension levels to be used in this procedure. This study was conducted on 10 tendons of the human gracilis muscle and 10 tendons of semitendinosus muscle removed from five male cadavers whose mean age was 20.8 years. These tendons underwent 10 in vitro strain cycles at three levels of deformation (2.5, 3, and 4%) and the value of the deforming load used for each cycle was recorded. The statistical analysis demonstrated that in order to attain the same level of deformation during the 10 cycles there was a reduction in the value of strain applied to the graft, observed at the three levels of deformation. It was concluded that the semitendinosus tendon presents a more uniform mechanical behavior and that there is a need for new graft tensioning protocols that consider the force associated with deformation.

The effect of cyclic knee motion on the elongation of four-strand hamstring autograft in anterior cruciate ligament reconstruction: an in-situ pilot study

“…The 4 strand STG autograft of the present study was significantly lengthened with repeated knee flexion and extension, which might be associated with postoperative mechanical failure [6]. Beynnon BD et al [12] compared the 5-year follow-up results with or without pretension in ACL reconstruction and found that the graft elongation values produced by flexion of the knee that are outside the limits of the ACL result in significant increases in anterior knee laxity at long-term follow-up, while grafts with elongation values similar to the normal anterior cruciate ligament do not.…”

“…Several studies showed that the initial graft tension would influence the results of ACL reconstruction [3–5]. In fact, the viscoelastic creep is associated with collagenous soft tissues under sustained tensile load and the graft elongation that occurs after fixation is a key factor in mechanical failure [6]. According to literatures, pretension of the viscoelastic graft before fixation could decrease the amount of elongation and the pretension treated graft has been shown to have significantly greater stiffness than the control group [7].…”

Pretensioning of Soft Tissue Grafts in Anterior Cruciate Ligament Reconstruction

“…5,6,24 Knee laxity is determined by the amount of tension that remains in the graft after reconstruction, and the graft elongation that occurs after fixation is a key factor in mechanical failure. 25,26 The anterior-to-posterior laxity of the knee decreases with an increase in initial tension of the ACL graft. 24,27,28 Inadequate tension with uncorrected laxity can lead to an unstable knee, 8 whereas overtensioning can lead to pathologic stress on joint cartilage, graft failure, or infrapatellar contracture syndrome.…”

“…14,25 Although patella tendon grafts are not typically pretensioned outside of the knee, there is no clear consensus on the ideal tensioning protocol for hamstring tendons. [13][14][15]26 Additionally, recreating a specific initial tension in the operating room can be difficult. Cunningham et al 21 showed that there is considerable variability in graft tensioning.…”

Artificial Organs 2006: A Year in Review

“…Sérgio Rocha Piedade et al. (65) of UNICAMP, Cidade Universitária (Campinas, Sao Paulo, Brazil) reported on cyclic loading of the human gracilis and semitendinosus muscle tendons from young male cadavers. The statistical analysis demonstrated that in order to attain the same level of deformation there was a reduction in the value of strain applied to the graft observed at the levels of deformation (2.5 to 4%).…”