summary Glenohumeral internal rotation deficit (GIRD) is a condition resulting in the loss of internal rotation of the glenohumeral joint as compared to the contralateral shoulder, most commonly seen in the throwing athlete. Diagnosis is made clinically with a decrease in internal rotation, increase in external rotation, with a decrease in total arc of rotation compared to the contralateral shoulder. Treatment consists of physical therapy with a focus on posteroinferior capsular stretching. Epidemiology Demographics occurs primarily in overhead athletes often seen in baseball pitchers Etiology Pathophysiology mechanism caused by repetitive throwing thought to occur during the late cocking and early acceleration phase pathoanatomy tightening of posterior capsule or posteroinferior capsule leads to translation of humeral head (capsular constraint mechanism) translation of humeral head is in the OPPOSITE direction from area of capsular tightening posterior capsular tightness leads to anterosuperior translation of humeral head in flexion posterorinferior capsular tightness leads to posterosuperior translation of humeral head in ABER anterior capsule is stretched Associated conditions glenohumeral instability internal impingement abutment of the greater tuberosity against the posterosuperior glenoid during abduction and external rotation leads to pinching of posterosuperior rotator cuff articular-sided partial rotator cuff tears tensile failure in excessive rotation internal impingement SLAP lesion throwers with GIRD are 25% more likely to have a SLAP lesion peel-back mechanism (biceps anchor and postero superior labrum peels back) during late cocking because of posterosuperior translation of humeral head and change in biceps vector force posteriorly Anatomy Glenohumeral joint Presentation Symptoms vague shoulder pain sometimes painless may report a decrease in throwing performance Physical exam stabilize the scapula to obtain true measure of glenohumeral rotation increased sulcus sign due to stretching of anterior structures that resist external rotation (coracohumeral ligament, rotator interval) characterized by altered glenohumeral range of motion decrease in internal rotation and increase in external rotation if the GIRD (loss of internal rotation) is less than external rotation gain (ERG), the shoulder maintains normal kinematics if the GIRD exceeds external rotation gain (ERG), this leads to deranged kinematics decrease in internal rotation is usually greater than a 25° difference as compared to non-throwing shoulder Imaging Radiographs recommended views AP and lateral of glenohumeral joint findings usually normal CT may show increased glenoid retroversion MRI ABER view on MRI can show associated lesions Treatment Nonoperative rest from throwing and physical therapy for 6 months indications first line of treatment physical therapy posteroinferior capsule stretching sleeper stretch performed with internal rotation stretch at 90 degrees abduction with scapular stabilization roll-over sleeper stretch arm flexed 60° and body rolled forward 30° doorway stretch cross-body adduction stretch pectoralis minor stretching rotator cuff and periscapular strengthening outcomes 90% of young throwers respond to sleeper stretches/PT 10% of older throwers do not respond, and will need arthroscopic release eventually Operative posteroinferior capsule release vs. anterior stabilization indications only indicated if extensive PT fails Techniques Posterior capsule release vs. anterior stabilization some advocate posterior capsule release while others advocate anterior stabilization repair thinned rotator cuff if significantly thinned (transcuff or takedown and repair) technique controversial for throwing athlete with posteroinferior capsular contracture, release posterior inferior capsule and posterior band of IGHL electrocautery inserted through posterior portal, camera from anterior portal from 9 to 6 o'clock position at level of glenoid rim until rotator cuff fibers (behind the capsule) can be seen from within joint insert arthroscopic shaver to widen gap in capsule (prevents recurrence) gentle manipulation at the end completes release of any remaining fibers, maximizes IR and flexion results will immediately gain 65° of internal rotation postop Complications