Pretensioning of Soft Tissue Grafts in Anterior Cruciate Ligament Reconstruction

Abstract

To determine which preconditioning and pretensioning techniques should be applied to soft tissue grafts during anterior cruciate ligament (ACL) reconstruction to avoid loss of tension after surgery, fresh semitendinosus and tibialis anterior tendons underwent tensile mechanical testing with 4 pretensioning and/or preconditioning techniques. A mechanical tester was used to collect the data. Group I (n=5) was given only an initial 80 N pull for tensioning, Group II (n=4) was given pretensioning and initial tensioning, Group III (n=5) was given cyclic tensioning and initial tensioning, and Group IV (n=5) was given a combination of the 3 techniques. Group I lost 50% of the initial tension at 30 minutes. The residual tension in Groups II, III, and IV was significantly higher than that in Group I after 1, 10, and 30 minutes (P<.001). Group IV consistently showed significantly higher residual tension than Groups II and III after 10 and 30 minutes (P<.05). All groups experienced elongation during testing: Group I (10.8 mm)<Group IV (14.6 mm)<Group III (15.6 mm)<Group II (16.6 mm), with significant differences observed between groups (P<.05). All experimental groups showed significantly greater stiffness than the control group (Group I) (P<.001). This study confirmed that pretensioning or preconditioning after 30 minutes leaves a graft with higher residual tension. Moreover, pretensioning and preconditioning had an additive effect and resulted in significantly greater retained tension than either method performed individually. A simple pull up to 80 N before fixation does not impart sufficient tension to a graft to prevent it from failing. The authors recommend that clinicians performing ACL reconstructions with soft tissue grafts precondition or pretension the tendons before final tibial fixation to achieve greater retained tension in the graft after placement.

Evaluation of Anterior Cruciate Ligament Surgical Reconstruction Through Finite Element Analysis

“…Therefore, the values for these two parameters are commonly surgery choices as stated above. The pretension value of 80 N is in the range of the maximum single hand pull that a surgeon can apply and a commonly accepted pretension value as stated above 7,103,104 . We also recorded peak values of the graft maximum principal stresses, which in almost all cases were observed around the femoral tunnel entry point similar to other studies 24,28,30,31,[42][43][44]49 .…”

Graft Retensioning by Dialing of Suture Disk on Tibial-Side Fixation in Arthroscopic Anterior Cruciate Ligament Reconstruction: Pathak Pune Dialing Technique

“…Pilia et al 16 studied pre-tensioning of soft-tissue grafts in ACL reconstruction. They considered graft tensioning a critical surgeon-controlled factor that affects ACL reconstruction outcomes.…”

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

“…Other than the static pretension of 60-80 N for 10–20 min, which was usually used for graft pretention, the method of repeated knee flexion and extension was performed in the present study. Pilia M et al [7] confirmed that a simple pull up to 80 N before fixation does not impart sufficient tension to a graft to prevent it from failing and they recommend precondition or pretension the tendons before final tibial fixation to achieve greater retained tension in the graft after placement. Lee CH et al [11] compared different commonly used pretension techniques for ACL reconstruction (manual, extra-, and intra-articular pretension) and the results suggested that the intra-articular pretension of the graft before final fixation can significantly minimize graft elongation at time 0 compared with the other methods.…”

“…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]. Thus applying tension to the ACL graft has been a technically important aspect of ACL reconstruction to prevent post-implantation graft creep [8, 9].…”