Summary

High-grade anterior tibial translation after ACL reconstruction is associated with the posterior tibial slope, preoperative anterior tibial translation, and the duration of ACL deficiency.

Abstract

Introduction

Excessive anterior tibial translation (ATT) in extension (> 10mm) has been identified as a factor associated with the failure after primary anterior cruciate ligament (ACL) reconstruction (ACLR). The purpose of this study is to investigate the factors associated with increased ATT after ACL reconstruction.

Methods

Between 2016 and 2021, 290 consecutive patients diagnosed with ACL injuries who underwent primary ACL reconstructions were retrospectively reviewed. Among them, 196 knees which ATT could be assessed using standing lateral radiographs of the knee both preoperatively and postoperatively were included in the analysis. Postoperative ATT in extension was categorized into high grade (>5 mm) and low grade (≤5 mm). Predictors of high-grade postoperative ATT in extension, including age, sex, body mass index, affected side, time period from injury to surgery, and posterior tibial slope (PTS), were evaluated using univariate analysis and multivariate logistic regression analysis.

Results

The average preoperative ATT was 7.5 mm, and the ATT at 1 year after ACLR was 4.6 mm (median 5 mm). The average PTS was 10°. 160 knees had a postoperative ATT of 5 mm or less, while 36 knees had an ATT exceeding 5 mm. Comparison between these groups revealed that preoperative ATT (cutoff value >8.2 mm), PTS (cutoff value >12°), and the time period from injury to surgery (cutoff value >7 months) were significantly associated with the high-grade postoperative ATT.

Conclusion

This study revealed that high-grade postoperative ATT is associated with a steep PTS (> 12°) , increased preoperative ATT (> 8.2 mm), and chronic ACL deficiency (> 7 months).