This review proposes the ABC classification for posterior glenohumeral instability, one of the most commonly misdiagnosed shoulder pathologies. It sorts PGHI by the nature of instability into three groups, each with two pathomechanism-based subtypes. The goal is a simple framework that links each category directly to a treatment recommendation.
When a young patient reports vague shoulder pain, weakness, or clicking rather than a clear dislocation, keep posterior instability on your list. It is one of the most commonly missed shoulder diagnoses and may represent up to 24% of surgically treated instability in young active patients.
The practical power of the ABC framework is that the subtype number tells you the treatment path. Type 1 lesions (subluxation, functional, constitutional) get conservative care. Type 2 lesions (dislocation, structural, acquired) get individualized surgical consideration.
The highest-yield pitfall is functional dynamic instability (B1). Operating on aberrant muscle patterning usually fails and worsens pain, so treat these with physiotherapy focused on scapular coordination and external rotator activation.
On the structural side, learn the gamma angle >90° threshold for an engaging reverse Hill-Sachs lesion, and remember that subtypes overlap and can progress, so reassessment over time matters.
This review proposes the ABC classification for posterior glenohumeral instability, one of the most commonly misdiagnosed shoulder pathologies. It sorts PGHI by the nature of instability into three groups, each with two pathomechanism-based subtypes. The goal is a simple framework that links each category directly to a treatment recommendation.
When a young patient reports vague shoulder pain, weakness, or clicking rather than a clear dislocation, keep posterior instability on your list. It is one of the most commonly missed shoulder diagnoses and may represent up to 24% of surgically treated instability in young active patients.
The practical power of the ABC framework is that the subtype number tells you the treatment path. Type 1 lesions (subluxation, functional, constitutional) get conservative care. Type 2 lesions (dislocation, structural, acquired) get individualized surgical consideration.
The highest-yield pitfall is functional dynamic instability (B1). Operating on aberrant muscle patterning usually fails and worsens pain, so treat these with physiotherapy focused on scapular coordination and external rotator activation.
On the structural side, learn the gamma angle >90° threshold for an engaging reverse Hill-Sachs lesion, and remember that subtypes overlap and can progress, so reassessment over time matters.