Acromio-clavicular Joint Pathology Presenting as Recurrent Shoulder Dislocations

Demonstrating the position of the acromio-clavicular joint. Palpation of this joint is important in assessment of possible shoulder dislocations.

Demonstrating the position of the acromio-clavicular joint. Palpation of this joint is important in assessment of possible shoulder dislocations.

By Dr Terry Hammond
MBBS FRACS Orth

Case 1:
A 26 year old man was referred to me with possible shoulder instability having had two apparent shoulder dislocations after falls from his motor-bike. There was no imaging available as he had been seen in remote locations. 

Examination confirmed no shoulder instability but instead showed an injury to the acromio-clavicular joint.
 
Case 2:
A 12 year old girl was referred with a history of apparent atraumatic shoulder instability. She felt her shoulder "dislocate" every time she lifted her arm above her head.
Clinical examination revealed the shoulder was stable but in fact she had instability of the acromio-clavicular joint.
 
These cases demonstrate that a history of possible shoulder dislocation may instead represent acromio-clavicular joint pathology. The most important clinical findings are tenderness over the acromio-clavicular joint or a feeling of instability occurring at the acromio-clavicular joint with arm movements.  The above photo shows the position of the acromio-clavicular joint.  You will note it is very close to the skin and easily palpable.
 
All patients with a possible shoulder dislocation should have their acromio-clavicular joint examined.  This may prevent an incorrect diagnosis of glenohumeral joint dislocation when in fact the acromio-clavicular joint is the source of pathology.