Study of ACL reconstruction failures shows that half of them are due to technical faults . This is true for all types of transplants and specially for those involving synthetic materials, which are less tolerant than autogenous tissues .
As a whole the ACL is not isometric. It is globally taut in extension and relaxed for a 90° knee flexion . However, some transitional fibers are close to isometry as it has been shown by many authors(Daniel- Abbink-Bradley).
