Dimensional assessment of continuous loop cortical suspension devices and clinical implications for intraoperative button flipping and intratunnel graft length

Abstract

Continuous loop cortical suspension devices have been demonstrated to be more consistent and biomechanically superior compared to adjustable loop devices; however, continuous loop devices present unique challenges compared to adjustable loop devices, especially in short tunnel reconstruction applications. Specifically, adjustable loop devices have the advantage of a "one size fits all" approach, and the ability to tension these devices following button flipping allows for the intratunnel graft length to be maximized. Nevertheless, the reliability of continuous loop devices has sustained their widespread use. We hypothesized that continuous loop cortical suspension devices from different manufacturers would exhibit equivalent 15 mm loop lengths, as advertised. Loop length was measured using a tensile testing machine. Contrary to our hypothesis, continuous loop cortical suspension devices with equivalent advertised lengths exhibited different loop lengths (up to 27% discrepancy). Inconsistencies with regards to manufacturers' reported loop lengths for continuous loop devices could have serious clinical implications and additionally complicate technique transferal among devices. Consequently, the manufacturers' accurate and complete disclosure of the dimensions and specifications associated with each continuous loop device is critical. Furthermore, surgeon awareness of true loop length dimensions and inconsistencies among devices is needed to ensure optimal implantation and resultant clinical outcomes.

Both Adjustable and Fixed Loop Hamstring Tendon Graft Fixation Have Similar Clinical and Patient-Reported Outcomes in Anterior Cruciate Ligament Reconstruction

“…ALDs possess the advantage of the “one size fits all” approach, conferring users the ability to readjust the tension (tighten) after fixation, thus maximizing the intratunnel graft length. 35 Retensioning of ALDs after tibial fixation also has been shown to improve biomechanical outcomes. 32 ALDs are technically easier to use because of the ability to tweak the graft tension after tightening.…”

Application of two types of suspensory fixation in reconstruction of anterior cruciate ligament with a semitendinosus-gracilis graft: A randomized prospective study

“…Standard suspensory technique of titanium button fixation with a fixed-length loop requires a specific tunnel length that exceeds the length of the intratunnel portion of the graft 23,24 . The extra space is necessary for the button to go through the entire tunnel and back in order to fixate the graft; however, it also creates conditions for the so-called "bungee cord" effect, which is considered to be a major cause of graft tunnel dilatation and graft loosening, which in turn diminishes the functional result.…”