Femoral cortical button malposition rates in anterior cruciate ligament reconstruction: A retrospective review

The purpose of this study was to determine the rate of malposition of the femoral cortical button during anterior cruciate ligament reconstruction and to present a classification system of femoral cortical button positioning that is both accurate and reproducible. A total of 361 patients undergoing primary anterior cruciate ligament reconstruction during a 5-year period were identified, and postoperative button position was graded as follows: reduced and congruent (entirety of button <2 mm from cortex); reduced and incongruent (part of button <2 mm from cortex, part of button >2 mm from cortex); displaced (entirety of button >2 mm from cortex); intraosseous (all or part of button remains within bone); or ungradable. Radiographs were evaluated by 2 orthopedic surgeons at 2 time points to define interrater and intrarater reliability. A total of 312 buttons (86.43%) were reduced and congruent, 18 (4.99%) were reduced and incongruent, 10 (2.77%) were displaced, 13 (3.60%) were intraosseous, and 8 (2.21%) were ungradable based on the available postoperative imaging. There was outstanding interrater reliability, with an overall kappa value of 0.84. Intrarater reliability for raters 1 and 2 was 0.77 and 0.83, respectively, representing excellent intrarater reliability for both observers. Cortical button placement during femoral fixation in anterior cruciate ligament reconstruction is variable. This study presents a classification system for grading femoral cortical button placement that is accurate and reproducible. An organized grading scheme may be useful for future studies of the effect of cortical button malposition on stability and durability of fixation.