Glenohumeral Internal Rotation Deficit: Prime Suspect or Innocent Bystander?

PURPOSE OF REVIEW

Glenohumeral internal rotation deficit (GIRD) is a term used in the literature to describe the physiological adaptation that occurs in the dominant arm of the overhead-throwing athlete. The meaning of this term and the clinical significance and the rationale for its treatment have all been described with some ambiguity within the literature. GIRD as a measurement is multivariate. There is an adaptive bony component in humeral retroversion (HR) and muscular contributions in the form of thixotropy which can confound the capsular component of GIRD. Emerging diagnostic tools such as ultrasound can help differentiate between the bony and soft tissue contributions as well as provide a dynamic assessment in the throwing shoulder. The purpose of this review is to describe and differentiate between anatomical GIRD (aGIRD) and pathological GIRD (pGIRD), discuss the clinical significance of pGIRD and values reported within the literature, and describe its measurement and clinical treatment.

RECENT FINDINGS

Recent literature has demonstrated that GIRD alone is not associated with injury risk of the upper extremity in the overhead athlete. Although past literature has demonstrated pGIRD as increasing injury risk, other variables such as external rotation (ER) deficit, horizontal adduction deficit, and shoulder flexion deficit have been associated with injury of the upper extremity while GIRD did not. Further, an appreciation for the difference between adaptive GIRD and pathologic GIRD has recently been emphasized to ensure optimal treatment addresses the pathologic portion of GIRD. The recent focus on early treatment approaches to pGIRD may play a role in its diminished risk association. This review offers the term humeral retroversion (HR) Corrected GIRD as a more clinically sensitive value that may provide the clinician a more precise rationale for the treatment of pGIRD. Currently, diagnostic ultrasound is a reliable and valid method for measuring HR in the overhead-throwing athlete. Future research that validates clinical methods for assessing HR could provide utility for clinical decision-making in the absence of diagnostic ultrasound.

Effect of scapular stabilization during cross-body stretch on the hardness of infraspinatus, teres minor, and deltoid muscles: An ultrasonic shear wave elastography study

BACKGROUND

Posterior shoulder tightness is a contributing factor to shoulder injuries. Cross-body stretch is a method frequently prescribed to stretch the posterior shoulder structures. This stretching is performed horizontally adducting the shoulder with or without manual stabilization of the scapula by the therapist. However, no studies have investigated the effect of scapular stabilization during cross-body stretch using shear elastic modulus as an index of muscle hardness in vivo.

OBJECTIVES

The aim of this study was to quantitatively examine, using ultrasonic shear wave elastography, whether scapular stabilization during cross-body stretch effectively decreased the hardness of the infraspinatus, the teres minor, or the posterior portion of the deltoid muscles.

DESIGN

A randomized, repeated-measures, cross-over design.

METHOD

Twenty healthy men participated in this study. The shear elastic modulus of the teres minor, the superior and inferior portions of the infraspinatus, and the posterior portion of the deltoid were measured before, and immediately after cross-body stretch with and without scapular stabilization.

RESULTS

The shear elastic modulus of the superior and inferior portions of the infraspinatus decreased significantly after cross-body stretch with scapular stabilization, but there was no significant change in the shear modulus of the measured muscles after cross-body stretch without scapular stabilization.

CONCLUSIONS

Our results suggest that manual scapular stabilization during cross-body stretch effectively decreases the hardness of the infraspinatus muscle.