Introduction
Glenohumeral internal rotation deficit (GIRD) is the decreased range of motion, particularly internal rotation of the throwing shoulder, compared to the non throwing shoulder. The decrease in the internal rotation (IR) is about 20 degrees or greater compared to the contralateral shoulder. Internal rotation is the rotation of the shoulder towards the center of the body. GIRD may not always be a pathologic condition, and internal rotation may be decreased, but the total rotational motion of the shoulders is symmetric. The sum of internal and external rotation measured at 90 degrees of shoulder abduction is the total rotational motion (TRM). A loss of more than five degrees of TRM compared to the contralateral shoulder is considered a pathologic condition responsible for shoulder injuries and decreased shoulder strength.
Who Are Affected by the Glenohumeral Internal Rotation Deficit?
GIRD usually affects people playing overhead sports. Overhead sports involve repeated throwing activities at high speeds generated by synchronizing the upper and lower limbs. It is primarily seen in sportspersons, athletes, especially overhead throwers, and baseball pitchers. It is also seen in tennis players, swimmers, gymnasts, javelin, and discus throwers. In some cases, bilateral GIRD may be seen, especially in gymnasts who apply symmetric loads on both shoulders.
What Are the Causes of GIRD?
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Throwing is a highly complex motion that involves significant velocities and extreme forces. Repeated throwing activity at high speeds causes continuous stress, which induces chronic changes in the shoulder and elbow joints leading to the development of GIRD.
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A posteroinferior glenoid bone spur is seen in overhead athletes due to the traction of the inferior glenohumeral ligament; it was first described by Bennett and is called Benett's lesion.
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Posterior capsular and rotator cuff tightness is seen in GIRD due to repeated cocking, which occurs in the overhead throwing motion.
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Extreme levels of stress on the static and dynamic stabilizers of the shoulder, which includes the rotator cuff muscles, joint capsule, and labrum, make it more prone to injuries like ligament tears, labral tears, rotator cuff tears, etc.
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In some rare cases, a severe traumatic injury may also lead to GIRD.
What Are the Signs and Symptoms of GIRD?
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A vague shoulder pain, which increases with overhead activities.
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Tenderness of the posterior joint line and surrounding soft tissues on palpation.
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Decrease in speed and control of throws in baseball players.
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Decreased movement and tightness of the affected shoulder.
What Are the Changes Seen in the Shoulders of Athletes With GIRD?
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Bony changes include the retroversion of the humeral head and glenoid bones.
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Thickening of the posterior capsule of the shoulder joint due to excessive pressure.
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Tightness of the shoulder muscles and surrounding structures.
What Are the Associated Conditions of GIRD?
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Superior labral anterior to posterior tears (SLAP) is a hallmark lesion seen in GIRD. It occurs due to increased external rotation of the shoulder, which causes impingement of the humeral head tuberosity against the labrum of the glenoid.
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GIRD can lead to altered motion and position of the scapula in relation to the thoracic cage, leading to abnormal functioning of the shoulder complex, called scapular dyskinesis.
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Scapular malposition, inferior medial border prominence, coracoid pain, and malposition, dyskinesis of scapular movement (SICK syndrome) are seen in patients with GIRD.
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Rotator cuff lesions are seen in most patients with GIRD due to repeated overhead activity, leading to pain and weakness of the muscles.
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Inflammation of the bursa or the tissue sac under the acromion process of the shoulder, causing pain, is called subacromial bursitis.
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Ulnar collateral ligament tears are caused due to frequent overarm movement, which ranges from only inflammation to ligament tears.
How Is GIRD Diagnosed?
The doctor takes a complete medical history, followed by a physical examination of the shoulder to determine the range of motion. Palpation over the joints shows tenderness, especially in the posterior region and the surrounding soft tissues. The assessment of GIRD can be done by the following methods:
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Measurement of loss of internal rotation, active and passive range of motion by a goniometer. TRM must be symmetrical in both shoulders, and a difference of more than 20 degrees, usually confirms the diagnosis of GIRD.
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Assessment of posterior tightness is done by asking the patient to lie down on the lateral side. The affected shoulder is held upside at an angle of 90 degrees, and the shoulder is brought towards the floor, with maximum adduction. In this movement, the travel of the humerus is measured on both sides. Loss of four centimeters, in comparison to the normal shoulder, almost confirms the diagnosis.
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Radiography is usually non-diagnostic in cases of GIRD; ultrasonography can be used to assess humeral torsion.
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Magnetic resonance imaging (MRI) is the most preferred method in diagnosing any associated pathology like tendon or ligament tears.
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Magnetic resonance arthrography (MRA) may also be used to detect the thickness of rotator cuff muscle tears and SLAP lesions and to rule out any underlying pathologies. Better visualization of rotator cuff tears can be obtained by MRA in the abduction and external rotation (ABER) position and is considered in symptomatic athletes.
How Is the Glenohumeral Internal Rotation Deficit Managed?
GIRD is usually managed with nonoperative methods, and in some rare cases, by surgical treatment. Nonoperative methods include: stretching and strengthening the posterior capsule of the shoulder joint leads to improvement in the scapula's movement and relieves pain. The most common stretching mechanism followed are:
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Sleeper-Stretch Method: In this method, the patient lies sideways, with elbows and shoulder flexing at an angle of 90 degrees, with the stabilized scapula and with the normal shoulder with the affected shoulder maximally rotated internally.
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Cross-Body Stretch Method: It is performed in a standing position, with a flexed shoulder, at 90 degrees. The affected shoulder is maximally rotated internally using the normal shoulder that applies pressure over the elbows.
Surgical management is necessary when the nonoperative methods do not provide relief. The aim of surgical management is to restore the function of the joint with minimum intervention. Arthroscopic shoulder surgery is the treatment of choice. Surgical repair of SLAP tears is done only in young and active individuals. However, in most cases, the outcome of the surgery is poor, and return-to-play rates are also low. In some severe cases, the capsular release is performed in 6'o clock or 11'o clock positions of the shoulder to completely expose the posterior rotator cuff muscle bellies and is called arthroscopic posteroinferior capsular release.
Conclusion
GIRD is the decrease in internal rotation of the throwing shoulder compared to the non throwing shoulder. It is commonly seen especially in overhead sports athletes and baseball pitchers. An increase in the prevalence of GIRD is seen recently due to an increase in competition for overhead sports athletes. It is associated with vague shoulder pain, tightness of the shoulder muscles, and decreased range of motion. The diagnosis is often made clinically, along with a few radiological findings. It can be managed by both conservative and surgical treatments. As it is asymptomatic in most individuals, It is essential for the players to undergo frequent screening to prevent the occurrence of glenohumeral internal rotation deficit.
