One of the most often torn ligaments in the body is the anterior cruciate ligament (ACL). The ACL is one of the ligaments crucial to knee stability and persons who tear their ACL often seek to undergo reconstructive surgery, which can be done through a variety of techniques and materials. One of these techniques is the replacement of the ligament with an artificial material. An artificial ligament is a reinforcing material that is used to replace a torn ligament, such as the ACL. Artificial ligaments are a synthetic material composed of a polymer, such as polyacrylonitrile fiber, polypropylene, PET (polyethylene terephthalate), or polyNaSS poly(sodium styrene sulfonate).  Ligaments are connected to the nerve system so do not tear them.
Q. I did a bad movement with my knee during a ball game. How can I know if I damaged the knee ligaments? 4 hours ago I played basketball. I did a great jump but when I landed I felt a very sharp knee pain? How can I know if I damaged the ligaments there? A. The only way to know for sure is to check! Can estimate the severity of the problem. Is your knee red? Is it hot? Is it swollen? Does the pain have the same severity or does the pain increase with time? If you answered one of those questions with a 'yes' several hours after the injury, you should probably talk to your GP
The sacrum is a large wedge shaped vertebra at the inferior end of the spine. It forms the solid base of the spinal column where it intersects with the hip bones to form the pelvis. The sacrum is a very strong bone that supports the weight of the upper body as it is spread across the pelvis and into the legs. Developmentally, the sacrum forms from five individual vertebrae that start to join during late adolescence and early adulthood to form a single bone by around the age of thirty. A ridge of tubercles along the posterior surface of the sacrum represents the spinous processes of these fused bones.