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Pearls: How to Perform a Controlled Adjustable Loop Suspensory Button Flip Under Direct Visualization During ACL Reconstruction

Fabricant, Peter D. MD, MPH

Author Information
Clinical Orthopaedics and Related Research: September 2019 - Volume 477 - Issue 9 - p 1999-2001
doi: 10.1097/CORR.0000000000000905.

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 [2]. 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 [1].

This increase in ACL injury incidence has resulted in a commensurate increase in ACL reconstruction procedures [2]. 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 [4], or an outside-in trans-iliotibial band endoscopic technique through which final implant seating may be confirmed but not performed under direct visualization [3]. 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).

Fig. 1A-D
Fig. 1A-D:
An adjustable loop suspensory fixation button is opened and prepared. In the event that there is only a passing suture (A, arrow) and tensioning sutures (A, arrowhead), an additional flipping suture may be passed through the opposite button hole; care should be taken not to use any sharp passing devices in order to prevent penetration of the tensioning mechanism; in this case, I used a 2-0 blunt waxed non-absorbable suture (B). The passing (C, arrow, thick strand) and flipping (C, asterisk, thin strand) sutures are each tied to prevent tangling, and the tensioning sutures (C, arrowhead) are left free. The button is oriented for passage such that the passing suture leads (D, arrow, thick strand) and the flipping suture trails (D, asterisk, thin strand). (Published with permission from Peter D. Fabricant MD, MPH).
Fig. 2A-C
Fig. 2A-C:
Tunnels are drilled including a femoral socket to accept the graft on a suspensory fixation device. A passing suture is placed (A, left knee), and then the button-based sutures are passed up the tibial tunnel and into the femoral socket. With the knee flexed to 90°, the arthroscope is moved to the medial portal, positioned at the intra-articular opening of the femoral socket, and the light source is amplified to maximal brightness. The button (B, arrow) is pulled with the leading suture (B, thick strand) into the pilot hole of the lateral femoral cortex under direct visualization. Once the button is engaged in the pilot hole and with gentle downward tension on the graft, the passing suture is released and only the flipping suture (B, arrowhead) is pulled which continues to advance the button in line with the pilot hole with tension on the trailing end of the button only (C). (Published with permission from Peter D. Fabricant MD, MPH).
Fig. 3A-B
Fig. 3A-B:
As the button clears the pilot hole with tension only on the flipping suture, the button flips immediately as the trailing edge clears the pilot hole (A, arrow). Downward tension on the graft confirms seating, however at the surgeon’s discretion, a single fluoroscopic image may be used to document appropriate implant position (B, arrow) in the patient’s medical record. (Published with permission from Peter D. Fabricant MD, MPH).

Acknowledgment

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.

References

1. Beck NA, Lawrence JTR, Nordin JD, DeFor TA, Tompkins M. ACL tears in school-aged children and adolescents over 20 years. Pediatrics. 2017;139:e20161877.
2. Dodwell ER, Lamont LE, Green DW, Pan TJ, Marx RG, Lyman S. 20 years of pediatric anterior cruciate ligament reconstruction in New York State. Am J Sports Med. 2014;42:675-680.
3. Mistovich RJ, O'Toole PO, Ganley TJ. Pediatric anterior cruciate ligament femoral fixation: The trans-iliotibial band endoscopic portal for direct visualization of ideal button placement. Arthrosc Tech. 2014;3:335-338.
4. Skelley NW, Stannard JT, Laupattarakasem P. Direct visualization of suspensory fixation deployment in knee ligament reconstructions without fluoroscopic imaging. Orthopedics. 2018;41:587-590.

Supplemental Digital Content

© 2019 by the Association of Bone and Joint Surgeons