Archer's shoulder. Recurrent posterior subluxation and dislocation of the shoulder in two archers.

Two right-handed archers presented with posterior instability of the shoulder. A 19-year-old Japanese and a 26-year-old white male archer developed pain and instability of the shoulder of 6 months' duration. Both had engaged in archery for several years. Both exhibited a positive apprehension test and recurrent posterior subluxation and dislocation by flexing the arm to 80 degrees with internal rotation. Both could reduce the instability with a snap by extending the arm. For the subluxation, Neer's inferior capsular shift procedure via a posterior approach was performed. For the dislocation, a posterior bone block was added to the inferior capsular shift. The posterior capsular redundancy was marked in both cases. At 5 and 9-years follow up respectively, both were doing archery and full activities without pain. These cases are thought to be examples of how a repetitive force can cause shoulder instability.