Statistical Analysis

All patients who were assigned to a treatment were included in statistical analyses, except for 1 participant who was dropped from the study because he did not undergo his scheduled ACL surgery. Between-group comparisons were made with the Mann-Whitney U test for continuous variables or the Fisher exact test for categorical variables. All statistical analyses were carried out using Stata Version 13 (StataCorp).

An a priori power analysis was performed using nQuery Version 4 (Stasols) to estimate the number of participants needed to find a statistically significant difference in lean mass. Preliminary data were taken from a study that found a change in lean mass of 3.0 ± 1.5 kg in healthy men receiving testosterone.⁴⁶ Using a significance level of 0.05 and a power of 0.80, a sample size of 6 participants per group was calculated to observe similar effects. Assuming a dropout rate of 20%, it was estimated that 14 patients would be needed in total.