Risk Factors for Femoral Cortical Button Malposition in Posterior Cruciate Ligament Reconstruction

Abstract

Background: Femoral cortical button suspension fixation is a popular and reliable technique for posterior cruciate ligament reconstruction (PCLR). Button malposition during graft fixation can lead to postoperative graft loosening.

Purpose: To determine the risk factors of femoral cortical button malposition in PCLR when neither direct visualization nor intraoperative fluoroscopy is used.

Study design: Case-control study; Level of evidence, 3.

Methods: Of the 206 consecutive patients who underwent PCLR without direct visualization or intraoperative radiographs in 2019 at a single institution, 182 met the selection criteria and were included in the study. The distance from the suspension button to the femoral cortex was measured on postoperative computed tomography scans. The button was considered malpositioned if its distance to the femoral cortex was ≥2 mm. We evaluated patient-related and surgery-related variables, including age, sex, concomitant ligament reconstruction, button type, and surgeon experience. Multivariate logistic regression was conducted to evaluate the risk factors for button malposition.

Results: The overall prevalence of button malposition was approximately 17.0% (31/182), and the mean distance from the button to the femoral cortex was 6.11 ± 5.82 mm in the malposition group. Male sex was the most significant risk factor for button malposition (odds ratio [OR], 13.86; 95% confidence interval [CI], 1.73-111.17; P = .013). Other independent risk factors were low surgical volume (completing ≤3 procedures; OR, 6.41; 95% CI, 1.89-21.72; P = .003), concomitant ligament reconstruction (OR, 5.56; 95% CI, 2.12-14.58; P < .001), and fixed-loop button (OR, 3.96; 95% CI, 1.11-14.18; P = .034).

Conclusion: Male sex, low surgical volume, concomitant ligament reconstruction, and fixed-loop button were independent risk factors for femoral cortical button malposition during PCLR.

Keywords: button malposition; femoral cortical button; posterior cruciate ligament reconstruction; suspensory fixation.

Figure 1.

Measuring the shortest distance from the inferior surface of the cortical button to the medial femoral cortex (green line) on axial CT sequence. CT, computed tomography.

Figure 2.

Femoral cortical button positions as shown on axial CT sequence. (A) A button was considered correctly positioned when the entirety of the button was completely in contact with the femoral cortex or the distance from the inferior surface of the cortical button to the medial femoral cortex was <2 mm. (B) A button was considered malpositioned if the distance from the inferior surface of the cortical button to the medial femoral cortex was ≥2 mm. (C) A button beneath the femoral cortex was excluded from the analysis. CT, computed tomography.