YOUR HANDLE KNOWS...
90% of all sliding patio door handles are designed to only withstand the normal pressure of opening and closing the door when the door itself is in good operating condition.
A loose or broken handle is the first sign that something else is not right. If you replace the handle without determining the underlying cause, which is usually improving the ease at which your door moves, you will be buying another handle in the near future.
A few of the common handle designs can be found at your local home center and the other hundred styles are available to be ordered. Rarely are handles found to be obsolete. http://www.allaboutdoors.com/index.php?cPath=74_80&osCsid=937574de2dc41f93bf2bd7eafe30cce5
Most handles are secured by two or more mounting screws. The distance between the centers of these screw holes is an important factor in locating the correct part.
BROKEN LATCH LEVERS...
Most handles incorporate a latch lever or thumb turn that move the locking latch open and closed. When the door is rolled to the fully open position, no part of the handle should bump into anything.
A "bumper" (or two) is/are usually installed at the jamb or track to prevent the door from opening so far that the latch lever or handle will hit the frame of the stationary panel.
A latch lever or thumb turn should never require much force to move the latch mechanism. Don't force it.