Acromioclavicular (AC) joint dislocation

• A patient complains of pain. He falls down on his right shoulder 1 week ago.

Plain X-ray: AP view

• Figure 1: non annotated image [test yourself]
• Figure 2: Superior displacement of the distal clavicle above the level of the superior border of the acromion [yellow arrows]
• Figure 3:

• Widening of the acromioclavicular joint measuring about 11.7 mm between opposing ends. [solid yellow arrow]
• Increased coraco-clavicular distance measuring about  21 mm between opposing ends. [dotted yellow arrow]

• In most cases, plain radiographs (including an axillary view) are sufficient for accurate grading which is important for management planning.
• In general types, I and II are treated conservatively, types IV, V, and VI are treated surgically, and type III injuries are variably treated

– Report should contain the following:

• Grade [type] of subluxation of the clavicle
• Direction of dislocation (use axillary view)
• Presence of soft tissue swelling
• Bone fractures and Glenohumeral joint alignment

-The Rockwood classification

• Type I: clavicle not elevated with respect to the acromion
• Type II: clavicle elevated but not above the superior border of the acromion
• TypeIII: clavicle elevated above the superior border of the acromion but the coracoclavicular distance is less than twice normal (i.e. <25 mm)
• Type IV: clavicle displaced posterior into the trapezius
• Type V: clavicle is markedly elevated and coracoclavicular distance is more than double normal (i.e. >25 mm)
• Type VI: clavicle inferiorly displaced behind coracobrachialis and biceps tendons, which is rare