2015 ISAKOS Biennial Congress Paper #0

Increased Tibiofemoral Rotation Angle is Associated With Graft Failure After Anterior Cruciate Ligament Reconstruction

Chilan Bou Ghosson Leite, MD, PhD, Boston, MASSACHUSETTS UNITED STATES
Gergo B Merkely, MD, PhD, Boston, MA UNITED STATES
Evan M Farina, MD, Boston, Massachusetts UNITED STATES
Richard Smith, MD, PhD, Brookline, MA UNITED STATES
Simon Görtz, MD, Foxboro, MA UNITED STATES
Sean Hazzard, PA, Boston, MA UNITED STATES
Peter Asnis, MD, Boston, MA UNITED STATES
Christian Lattermann, MD, Foxborough, MA UNITED STATES
Brigham and Women's Hospital, Boston, MA, UNITED STATES

FDA Status Not Applicable

Summary: Increased tibiofemoral rotation angle was associated with increased odds of ACLR failure particularly if the angle is higher than 4.5 degrees.

Abstract:

Purpose

Anterior cruciate ligament reconstruction (ACLR) is a common surgical procedure, but failure rates remain a concern. While coronal and sagittal malalignment of the knee are known risk factors for ACLR failure, the impact of axial malalignment on graft survival is not well understood. This study aimed to investigate if increased tibiofemoral rotational malalignment, measured through tibiofemoral rotation angle (TFA) and tibial tubercle-trochlear groove (TT-TG) distance, is associated with ACLR graft failure.

Methods

This study compared 151 patients who underwent revision ACLR due to graft failure (failure ACLR group) to a matched-control group of 151 patients who underwent primary ACLR with no evidence of failure after at least 2 years of follow-up (intact ACLR group). Sex, age, and meniscal injury during primary ACLR were using for matching the groups. Preoperative magnetic resonance imaging (MRI) measurements of TFA and TT-TG distance were used to assess axial malalignment; posterior tibial slope (PTS) measured on MRI was used to sagittal alignment assessment. A receiver operating characteristic (ROC) curve was used to determine TFA cutoff value. The influence of TFA on ACLR survival was evaluated using a Kaplan-Meier curve with log-rank analysis.

Results

The mean TFA in the failure ACLR group was 5.8 ± 4.5 (range, -5 to 16) degrees, while in the intact ACLR group, the mean was 3.0 ± 3.3 (range, -3 to 15) degrees (p<0.001). There were no statistical differences between the groups in TT-TG distance or PTS. A TFA cutoff of 4.5 degrees for ACLR graft failure was determined by the ROC curve. Patients with TFA greater than 4.5 degrees had more than 5-times likelihood of graft failure than those with TFA < 4.5 degrees (p<0.001). Patients with TFA < 4.5 degrees had a 5-year survival of 81%; for those with TFA greater than 4.5 degrees, the 5-years survival rate was 44% (p<0.001).

Conclusion

An increased risk of ACLR failure was found when the TFA is higher than 4.5 degrees. Measuring TFA in patients with ACL injury that undergoes reconstruction may be an additional valuable information to be considered when planning ACLR.