Does Anterolateral Ligament Ultrasound Influences the Return-to-play After Anterior Cruciate Ligament Rupture? Survival Analysis

In this case series, the surgeon will decide which patient will have ACL only or ACL and ALL surgery on the basis on multiple parameters. All patient will undergo detailed pre-clinical evaluation, including an ultrasonographic evaluation of the integrity of the ALL.

Two subgroups will be compared for the primary outcome (International Knee Documentation Committee score at 8 months of follow-up). In subgroup 1, the surgeon will follow the ultrasonographic evaluation of the ALL considering the ALL repair (i.e. : ALL intact on the ultrasound, ACL repair only; ALL broken on ultrasound; ACL and ALL repair). In subgroup 2, the surgeon will not follow the ultrasonographic evaluation of the ALL considering the ALL repair.

Secondary outcomes of interest will be evaluated with multivariate regression analysis.

Sample size calculation:

The chosen parameter of interest for the primary outcome evaluation is a continuous response variable (IKDC score) from two independent subgroups (ultrasonographic evaluation of the ALL followed or not for the surgical repair), considering a ratio of 1:3 between the two subgroups. In a previous study (AJSM Sonnery-Cottet 2017) the response within each subject group was normally distributed with standard deviation 13.1. If the true difference between the group means is the published minimal clinically important difference of 9 (AJSM Nwachukwu 2017), we will need to study 30 experimental subjects and 90 control subjects to be able to reject the null hypothesis that the population means of the experimental and control groups are equal with probability (power) 0.9. The Type I error probability associated with this test of this null hypothesis is 0.05.