Most of the time, when a muscle tears, what is actually happening is the tendon rips off the bone, either partway or all the way. Sometimes the muscle tears in the middle but that's somewhat unusual (does happen though, often with certain muscles, like pecs). Basically, in a nutshell, this is how they are/was generally repaired: The 'old method' was to drill a hole in the bone and pull the tendon down into it and suture it there, the 'new method' is to place an anchor on the bone where the tendon will attach that will hold the tendon against the bone and let it grown back into the bone naturally over time.