Seventeen shoulders in ten adolescents were evaluated for non-traumatic
posterior instability. Each patient had significant disability in throwing
a ball, swimming, arm-blocking in football, and bench-pressing weights.
Each patient had excessive retroversion of the glenoid. Five shoulders had
a posterior opening-wedge osteotomy of the scapular neck to correct the
excessive retroversion of the glenoid cavity. Acromial bone was used as
graft material in the first four shoulders. Three shoulders lost some
correction but only one required revision, which was done using cortical
iliac bone as a graft and screw fixation. This technique was used primarily
in the fifth shoulder. Excessive retroversion of the glenoid cavity is a
developmental deformity and is considered the primary etiology of posterior
instability of the shoulder. The posterior opening-wedge osteotomy of the
scapular neck corrects the defect and the instability.