Summary

Analysis of risk factors of postoperative ACL graft failure in a large cohort of ACLR patients with and without a monoloop lateral extra-articular tenodesis (mLET).

Abstract

Introduction

Anterior cruciate ligament reconstruction (ACLR) is a well-established procedure to treat symptomatic ACL insufficient knees, but graft failure remains a feared complication. The purpose of this study is to analyze risk factors of postoperative graft failure in a large cohort of ACLR patients with and without a monoloop lateral extra-articular tenodesis (mLET).

Methods

A single center, two-surgeon, non-randomized clinical trial, with retrospective analysis of prospectively collected data focused on a population of 748 patients with an acute primary ACL tear. All patients were treated with quadrupled semitendinosus ACLR with minimal follow-up of 2 years (mean follow-up 50 months (24-89). Patient demographics were recorded. Categorical variables were sex (461M (61.6%), 287F (38.4%)), age below 25 years old (N=271, 36.2%), smoking (N=126, 16.8%), soccer (N=264, 35.3%), Tegner activity score (8 or higher) (N=273, 36.5%), meniscal injury (N= 318, 42.5%) and mLET (N=211, 28.2%). Primary outcome was graft failure, defined as the need for revision or symptomatic ACL instability. Statistical analysis was performed to identify predictors of ACL graft failure (univariate analysis, binary logistic regression analysis and model reduction). Finally, a subgroup analysis was performed on the populations at high risk to study the effect of mLET on graft failure.

Results

Mean age at surgery was 31 (13-61), mean weight 75.9kg (47-125), mean length 175cm (152-202), mean BMI 24.4 3 (18-39). Overall, graft failure was observed in 25/748 (3.34%) patients.
Following the predictive model, the likelihood of graft failure increased by a factor of 29.3 (p <0.001) if age below 25 years old; factor 7.4 if isolated ACLR without mLET (p=0.002); 4.4 (p=0.002) if playing soccer, 3.1 (p=0.021) if smoking, 2.8 (p=0.023) if associated meniscus injury.
The addition of mLET to ACLR reduced the risk of graft failure by a factor of 11.3 (p=0.002) in the age group below 25 years old. In patients with concomitant meniscal lesions, mLET reduced the likelihood of graft failure by a factor of 8 (p=0.01) and in soccer players by a factor of 5.2 (p=0.016). None of the smokers experienced graft failure after mLET.

Conclusions

In this large cohort study, the likelihood of ACLR graft failure was significantly increased in patients below 25 years old (RR 29.3), in isolated ACLR without mLET (RR 7.4), in soccer players (RR 4.4), in smokers (RR 3.1) and when concomitant meniscal injuries were diagnosed (RR 2.8). In contrast, the addition of mLET, as the only surgically modifiable predictor, actively reduced the risk of ACL graft failure in the study population, especially in the groups at risk (below 25, soccer, meniscus injury, smoker).