Summary

In 318 teenagers who underwent ACL reconstruction and lateral tenodesis, there was a 24.8% rate of second ACL injuries at an average 7-year follow-up, with male sex and high activity levels as significant predictors, and a higher incidence of contralateral injuries in the 15-17 age group.

Abstract

Introduction

Anterior Cruciate Ligament (ACL) injuries have grown in teenager population in the last decades, and surgical reconstruction resulted safe in the short term; however, high rate of second injuries are reported, with no clear role of age. The purpose of this study was to assess the rate and predictors of second ACL injuries, especially in relation to age.

Methods

All patients younger than 19 years that underwent ACL reconstruction with hamstrings over-the-top and lateral tenodesis between 2006 and 2017 were considered eligible for this study. All patients with a minimum follow-up of 2 years were contacted, and second ACL injuries (ipsilateral and contralateral) were registered. Multivariate analysis was performed according to age (13-15 vs 15-17 vs 17-19 years), Sex (Male vs Female), Activity level (Tegner <8 vs =8) and BMI (<25 vs =25).

Results

Out of the 386 eligible patients, 318 (82%) were available for evaluation. The mean age was 16.3 ± 1.4 years (22% 13-15 years; 43% 15-17 years; 35% 17-19 years), most were males (73%) and the average pre-operative Tegner was 7 (60% <8; 40% =8). During the average follow-up of 7.1 ± 3.5 years (2 – 14 years) a total of 32 (10.1%) Ipsilateral ACL re-ruptures and 53 (16.7%) Contralateral ACL ruptures were registered, for a total 24.8% of 2nd ACL Injury rate. Male sex was the only predictor of Ipsialteral (p=0.0069), Contralateral (p=0.0070) or 2nd ACL injury (p=0.0031). Age between 15-17 years was also predictor of having a Contralateral ACL injury. The higher rate of Ipsilateral re-injury (20%) was present in the Tegner =8 and age 17-19 years subgroup, while the higher rate of Contralateral ACL injury (26%) was present in the Tegner =8 and age 15-17 years subgroup
Risk of having a Contralateral injury was 1.64 times higher (p=0.0299) than having an Ipsilateral re-injury, especially in patients between 15-17 years (HR=2.55; p=0.0006).

Conclusions

Different patterns of Ipsialteral ACL re-injury or Conralateral ACL injury seems to be present according to age range, especially in patients with high level of activity at mid term, after ACL reconstruction with hamstrings and lateral tenodesis in teenager patients.