Testosterone Administration and ACL Reconstruction in Men

Inclusion Criteria: * A complete ACL tear as visualized on MRI * The ACL injury can be either "isolated" or combined with one or several of the following injuries visualized on MRI and/or arthroscopy: * a meniscus tear that is either left untreated or treated with a partial resection * a small, stable meniscus tear treated with fixation, but with the fixation not interfering with the rehabilitation protocol * cartilage changes verified on MRI with an arthroscopically determined intact surface. * A radiographic examination with normal joint status or combined with either one of the following findings: * a small-avulsed fragment located laterally, usually described as a Segond fracture, JSN grade 1 or osteophytes grade 1 as determined by the OARSI atlas15 Exclusion Criteria: * Previous major knee injury or knee surgery * Associated posterior cruciate ligament (PCL) or medical collateral ligament (MCL) injury grade III * Concomitant severe injury to contra-lateral knee * Injury to the lateral/posterolateral ligament complex with significantly increased laxity * Unstable longitudinal meniscus tear that requires repair and where the following postoperative treatment (we.e. bracing and limited range of motion) interferes with the rehabilitation protocol * Bi-compartmental extensive meniscus resections * Cartilage injury representing a full thickness loss down to bone * Total rupture of MCL/LCL as visualized on MRI. * History of deep vein thrombosis (DVT) or a disorder of the coagulative system * Claustrophobia * Prior or current use of anabolic steroids * General systemic disease affecting physical function * Chromosomal disorders * Medications that interfere with testosterone production or function, including but not limited to 5α-reductase inhibitors * Any other condition or treatment interfering with the completion of the trial