Shoulder problems are common among overhead throwing athletes. Anterior instability along the front of the shoulder occurs as a result of repetitive microtrauma. Posterior instability (along the back of the shoulder) is much less common. This condition occurs with repetitive microtrauma during the late cocking and follow-through phases of overhead throwing.
There aren’t very many reports on the treatment of posterior shoulder instability. In this study, arthroscopic repair of the posterior capsule and labrum is compared for overhead-throwing athletes compared with nonthrowers. Results were measured based on stability, motion, strength, pain and function.
All patients had unidirectional posterior instability. This means the instability was in one direction only rather than being multidirectional (present in more than one direction). The patients were all athletes but not all were throwing athletes. Differences were compared based on this one factor (throwers versus nonthrowers).
Surgery was done to stabilize the shoulders. Arthroscopic exam was performed to assess tissue damage and the location, direction, and amount of instability. Fraying or tears of the labrum (capsular rim) and the quality of the soft tissues around the shoulder were observed. Surgery to repair the damage was then done arthroscopically. The authors described the various types of surgical procedures used.
The authors report no differences between the two groups. Patients in both groups showed a big improvement in all areas tested. Throwing athletes did not always return to their preinjury level of sports participation. Overall, the results were good to excellent with only one case of poor results (among the nonthrower group).
Arthroscopic repair of posterior shoulder instability is effective. Improvements in stability, motion, strength, pain, and function were seen in patients with unidirectional instability. Pitchers who need stability with full motion may benefit from this type of procedure.