Femoral attachment of anterior cruciate ligament remnant tissue influences the stability of the anterior cruciate ligament-injured knee in patients over 40 years old

The uses of anterior cruciate ligament (ACL) remnant tissue as a potential accelerant of graft remodeling1e3 and promoter of better knee stability4 have recently attracted attention. However, ACL remnant tissue is generally resected during ACL reconstruction to provide a clear visual field.5 Several investigators have therefore developed and implemented a procedure that includes remnant tissue preservation and have subsequently observed better clinical outcomes compared to conventional reconstruction.6e8 Even years after an injury, ACL remnant tissue contains proprioceptive mechanoreceptors; therefore, it is considered as a potential source of re-innervation.5 However, contrasting reports suggest that the elapsed time after injury might affect the number of persistent mechanoreceptors9 and that the biomechanical contribution of remnant tissue is lost by one year post injury.10 Furthermore, the ACL remnant tissues of adolescent patients were reported to exhibit a significantly higher differentiation potential,11 and in a rat model of ACL reconstruction, remnant tissues from younger