2015 ISAKOS Biennial Congress ePoster #1315

Cortical Button Placement in Femoral Fixation of Anterior Cruciate Ligament Reconstruction: A Retrospective Review

Jeffrey A. Macalena, MD, Minneapolis, MN UNITED STATES
Andrew C. Toftoy, MD, Grand Forks, ND UNITED STATES
Alice Deden, BA, MLS, Minneapolis, MN UNITED STATES
Christopher Rud, BA, Minneapolis, MN UNITED STATES
University of Minnesota, Minneapolis, Minnesota, USA

FDA Status Cleared

Summary: Cortical button placement during femoral fixation in ACL reconstruction is widely variable and the use of intraoperative imaging does not appear to decrease the incidence of cortical button malposiition.

Abstract:

Introduction

Cortical buttons are frequently used for femoral fixation during anterior cruciate ligament (ACL) reconstruction. The incidence of malposition of the cortical button has not been studied. The purpose of this retrospective case review is to determine the incidence of cortical button malposition on postoperative radiographs. The primary hypothesis of this study is that cortical button malposition will be an infrequent occurrence with a prevalence of less than 5%.

Methods

After IRB approval, a retrospective review of all ACL reconstructions performed from September 2009 through May 2014 at a single center was completed. Only patients with cortical button femoral fixation and postoperative AP and lateral radiographs were included. Surgical variables were investigated including: femoral fixation, tibial fixation, graft type, meniscal involvement, articular cartilage involvement, surgical technique for drilling of the femoral tunnel, position of the button in relation to cortex, use of intra-operative imaging, and specific implant. Postoperative button position was graded as follows: reduced and congruent (button is <1mm from cortex); reduced and incongruent (part of button is <1mm from cortex, part of button is >1mm from cortex); displaced (all of button is >1mm from cortex); intraosseous (all or part of button remains within bone); ungradable (button cannot be graded based on radiograph). Radiographs were evaluated by two individuals at two time points to define inter- and intra-observer reliability.

Results

2,182 ACL patient’s charts were reviewed. A total of 563 patients had cortical button fixation of the femoral side of the graft. 361 of these patients had post-operative radiographs available for review. 245 (67.9 %) buttons were reduced and congruent. 49 (13.6%) buttons were reduced and incongruent. 40 (11.1%) buttons were displaced. 12 (3.3%) buttons remained intraosseous 15 (4.1%) buttons were deemed ungradeable. Intraoperative imaging was utilized in 121 patients. Of these, 59 (48.8%) were reduced, congruent; 46 (38.0%) were reduced, incongruent; 9 (7.4%) were displaced; 5 (4.1%) remained intraosseous; and 2 (1.7%) were ungradable. After the sample was re-graded, there was found to be intraobserver agreement 98% of the time.

Conclusion

Cortical button placement during femoral fixation in ACL reconstruction is widely variable. Use of intraoperative imaging does not seem to increase the incidence of reduced, congruent cortical buttons. Further research is warranted.


Key Words: cortical button fixation; ACL reconstruction