You aren't the first one to have scale shock after shoulder arthroscopy. Most folks notice between a two and 20-pound weight gain. The average weight gain is about 10 pounds.

A recent study from the University of Texas tracked weight change in patients before and after this surgery. They found the main cause was the fluid pushed into the joint to help separate the joint surfaces. It gives the surgeon a little more room to work in.

The more damage there is to the joint or the longer the surgery takes to finish, the more fluid is pushed into the area. This is the key factor causing the weight gain. Doctors have been advised to shorten the surgical time whenever possible.