There are some new statistics on return-to-sports after shoulder versus elbow surgery. It seems that athletes with surgically repaired elbow injuries have a better chance of recovery over those who have shoulder surgery.
The reasons for this aren't entirely clear. This was true even with experienced surgeons doing the operations. It may depend on the type of surgical repair. For example, in this one study, shoulder procedures included labral repairs, labral débridement, rotator cuff tear repair, and capsular release. Elbow problems required removal of loose fragments inside the joint, relocation of a nerve, and ligament reconstruction. Players with elbow injuries and surgery were more likely to return to pre-injury levels than athletes who had shoulder surgery.
Return to play statistics were kept for each group. It turned out that only one in 12 players at the upper league level was able to go back to his pre-injury level of play. Players with labral tears (shoulder injury) were more likely to retire from baseball after surgery.
However, with rehab, many players are able to return to the same or higher playing level after surgery. Sometimes players do retire after serious injuries. Some play at a lower level after recovery.