Table 3: The difference between ERO and IRO.

	External Rotation Osteotomy (ERO)	Internal Rotation Osteotomy (IRO)
Indication	Deformed glenoid (Waters VI, V, VI or Pearls “pseudoglenoid”)	Posterior dislocation of the shoulder with relatively normal glenoid Increase humeral retroversion Unstable shoulder joint after reduction of the glenohumeral joint and performing anterior shoulder release
Patient	Older children with dislocated shoulder	Young children with dislocated shoulder
Effect on the glenohumeral joint	Increase the deformity of the joint	Reduce the dislocated joint
Effect of humeral retroversion	Increase the humeral retroversion	Decrease the humeral retroversion
Effect on the range of shoulder external rotation	Increase	Decrease
Effect on the range of shoulder internal rotation	Decrease	Increase
Frequency	Commonly performed procedure	Rarely done procedure
Need of release of anterior capsule and internal rotator muscles	No need, sometime added	Has to be combined with internal rotator release +/- tendon transfer