Until recently, it was recommended that the elbow be placed in 90 degrees of flexion. Since there were no data to prove this was the best position, a group of researchers decided to investigate. After studying a group of healthy adults, it seems that a position of 110 degrees of flexion is best (slightly more than a right angle). This position allows for the most arm function.
Before you have this surgery, ask your doctor about a trial period with an adjustable brace. Try five or six different settings, and keep track of which activities you can and can't do in each. A physical or occupational therapist can help you with this. Other factors to consider include your occupation and work-related tasks, your personal preferences, and whether you are right- or left-handed.