Hi

I'll attempt to answer your question regarding the role of the scapula. It is a complex topic so here we go.

The role of the scapula is to provide a stable base for the shoulder joint and to move in a co-ordinated way in order to keep the ball and socket joint in optimal contact with each other and within a so called safe zone. The scapula contains the socket part of the ball and socket joint.....so as the arm moves (especially overhead) the ball moves, therefore the socket has to move accordingly. Any imbalance in this co-ordinated movement (called scapulohumeral rhythm )can cause problems.

ALSO the scapula provides a base for the stabilizing muscles to attach to. These stabilising muscles control the position of the scapula. Weaknesses and imbalances are common following shoulder dislocations and subluxations. If your scapula stabilising muscles are weak then they are unable to position your scapula in the appropriate place as your arm moves causing your shoulder joint to be susceptible to injury. This can either be in terms of further subluxations, or Wikipedia reference-linkrotator cuff impingement whereby the ball and socket become too close together during movement that they squash the rotator cuff tendons.

Confused??
You are on the right track with serratus anterior strengthening, but this needs to be done in conjunction with lower trapezius as these two muscles work together.

It's a complex problem so I would highly recommend you see an experienced physiotherapist who has dealt with this type of thing before. Even if you do have further surgery, you'll still need the rehab after that.

Hope this helps.