Gerber and Nyffeler propose a structured classification of glenohumeral instability dividing presentations into static (Class A), dynamic (Class B), and voluntary dislocation (Class C). The paper's central argument is that hyperlaxity and instability are distinct entities that must be separated before any treatment decision is made. The question it answers: how should the full clinical spectrum of shoulder instability be organized to guide diagnosis and therapy?
The sulcus sign has been misused for decades as a proxy for multidirectional instability — Gerber's classification is the corrective framework that untangles laxity from pathology.
When you examine a patient with shoulder instability, run through three questions in order: Is the head fixed out of place (static. Image it, not a physical exam diagnosis)? Is it episodically displaced (dynamic. Then determine hyperlaxity and direction)? Or is the patient in control of it (voluntary. Assess for psychiatric overlay before any surgical discussion).
The 7 mm acromiohumeral threshold and the 50% AP glenoid diameter rule are the two numbers that change operative planning: the first tells you the cuff is irreparable by conventional means, the second tells you soft tissue alone will fail and bone must be restored.
When a young female presents voluntarily dislocating for attention or secondary gain, the referral is to psychiatry. Operating on this group is a well-documented path to a poor outcome.
Gerber and Nyffeler propose a structured classification of glenohumeral instability dividing presentations into static (Class A), dynamic (Class B), and voluntary dislocation (Class C). The paper's central argument is that hyperlaxity and instability are distinct entities that must be separated before any treatment decision is made. The question it answers: how should the full clinical spectrum of shoulder instability be organized to guide diagnosis and therapy?
The sulcus sign has been misused for decades as a proxy for multidirectional instability — Gerber's classification is the corrective framework that untangles laxity from pathology.
When you examine a patient with shoulder instability, run through three questions in order: Is the head fixed out of place (static. Image it, not a physical exam diagnosis)? Is it episodically displaced (dynamic. Then determine hyperlaxity and direction)? Or is the patient in control of it (voluntary. Assess for psychiatric overlay before any surgical discussion).
The 7 mm acromiohumeral threshold and the 50% AP glenoid diameter rule are the two numbers that change operative planning: the first tells you the cuff is irreparable by conventional means, the second tells you soft tissue alone will fail and bone must be restored.
When a young female presents voluntarily dislocating for attention or secondary gain, the referral is to psychiatry. Operating on this group is a well-documented path to a poor outcome.