Anterior cruciate ligament reconstruction is among the most commonly performed knee operations in the United States. ACL injury rates are rising precipitously with recent studies in young athletes indicating an overall risk of 0.7% per season in females and 0.4% per season in males . Because the per-season risks are additive, an adolescent female athlete who participates in three athletic seasons per year for 10 years, for instance, has a 21% chance of an ACL injury during their youth sports career, on average .
This increase in ACL injury incidence has resulted in a commensurate increase in ACL reconstruction procedures . During ACL reconstruction surgeons are increasingly using adjustable suspensory button fixation for both soft tissue and bone block ACL graft fixation. Accurate confirmation of appropriate implant passage through the tunnel and lateral femoral cortex, button flipping outside the tunnel, and firm engagement with the lateral femoral cortex all are imperative; these steps frequently are performed and subsequently confirmed with fluoroscopic imaging.
Although a few techniques have been described for direct visualization of button flip and engagement, they either require intra-articular button placement , or an outside-in trans-iliotibial band endoscopic technique through which final implant seating may be confirmed but not performed under direct visualization . Intra-articular button placement is not ideal as it may eventually dislodge from the suture and create a loose intraarticular foreign body, and outside-in visualization helps confirm the button has seated but does not allow for direct visualization of button passage and flipping.
Performing a controlled adjustable loop button flip can be challenging—attempting to flip too soon will cause the button to stay within the femoral tunnel or socket and not engage the lateral femur, whereas advancing too far before flipping will result in interposed tissue such as the iliotibial band between the button and the lateral femoral cortex. Having interposed soft tissue between the button and the lateral femoral cortex may cause painful tethering of the iliotibial band or lateral thigh musculature, and increase creep in the system with resultant graft loosening. By adding an additional flipping suture (Fig. 1A-D) and appropriately timing the adjustable loop button flip under direct arthroscopic visualization (Fig. 2A-C) (Video 1, Supplemental Digital Content, http://links.lww.com/CORR/A213), precise tunnel length measurements are unnecessary, and the button may be placed extra-articularly with visual confirmation of button engagement. For additional confirmation, fluoroscopic imaging may be used to document appropriate implant position (Fig. 3A-B).
The author would like to thank Grace Wang BA for her assistance with preparation of the published figures, and Madison R. Heath BS for her assistance with video production.
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