Glenohumeral Internal Rotation Deficit: Prime Suspect or Innocent Bystander?

Area of Science:

• Orthopedics
• Sports Medicine
• Biomechanics

Background:

• Glenohumeral internal rotation deficit (GIRD) is a common adaptation in overhead-throwing athletes, but its clinical significance and measurement are often ambiguous.
• GIRD is multifactorial, influenced by bony adaptations like humeral retroversion (HR) and soft tissue factors such as thixotropy, complicating accurate assessment.
• Emerging diagnostic tools like ultrasound offer potential for dynamic assessment and differentiation between bony and soft tissue contributions to GIRD.

Purpose of the Study:

• To differentiate between anatomical GIRD (aGIRD) and pathological GIRD (pGIRD).
• To discuss the clinical significance and reported values of pGIRD in the literature.
• To describe current measurement techniques and clinical treatment strategies for GIRD.

Main Methods:

• Review of recent literature on GIRD in overhead athletes.
• Analysis of studies differentiating adaptive versus pathological GIRD.
• Evaluation of diagnostic tools, including ultrasound, for assessing humeral retroversion (HR).

Main Results:

• GIRD alone is not consistently associated with upper extremity injury risk in overhead athletes.
• Other deficits, such as external rotation (ER) and shoulder flexion deficits, show stronger associations with injury.
• The distinction between adaptive and pathological GIRD is crucial for targeted treatment, with early intervention potentially reducing risk.

Conclusions:

• The term "humeral retroversion (HR) Corrected GIRD" is proposed as a more clinically sensitive measure for guiding pGIRD treatment.
• Diagnostic ultrasound is a validated tool for measuring HR in throwing athletes.
• Further research is needed to validate clinical methods for HR assessment to aid clinical decision-making.