Review Question - QID 214098

The patient has sustained a type III AC joint injury which represents complete tearing of the acromioclavicular (ligament A) ligament and both coracoclavicular ligaments (ligaments C and D).

Acromioclavicular (AC) joint injury, otherwise known as a shoulder separation, is a traumatic injury to the AC joint with disruption of the AC ligament and/or coracoclavicular (CC) ligaments. The Rockwood classification is used to classify the injuries. Type I injuries involve purely an AC joint sprain with intact CC ligaments. Type II injuries involve complete tearing of the AC joint and a sprain of the CC ligament with the CC measurement being < 25% greater than of the contralateral shoulder. Type III, IV, V, and VI injuries all involve complete tearing of both the AC and CC ligaments. Type III injuries have a CC distance measurement between 25 and 100% greater than that of the contralateral side (this patient) compared to Type V injuries which have a CC distance > 100% of the contralateral side. Type IV and VI injuries represent posterior and inferior dislocation of the clavicle, respectively. The coracoacromial ligament is generally spared in these injuries.

Cook and Krul reviewed the treatment of AC joint injuries. They noted that nonsurgical therapy remains the mainstay for treatment of type I, type II, and most type III injuries, although recent biomechanical and biokinetic data might suggest that patients are more affected than traditionally thought. They state that type IV, V, and VI injuries often necessitate surgical intervention, although little consensus exists on the timing or technique. They discuss that more biomechanical and kinematic data is needed to assist with the management of these injuries.

Dunphy et al. performed a retrospective chart review of non-operative management of type V AC joint injuries. The authors reviewed 22 patients with a mean age of 42 who sustained type V AC joint injuries managed non-operatively with an average of 34 months followup. They noted that patients with normal DASH (≤10) and ASES (>92) scores at the final follow-up were younger than those with abnormal scores. They also noted that at final assessment, 77% of the patients were currently working, with nine patients performing manual labor. The authors concluded that following nonsurgical management of type V AC injuries, most patients are able to return to work but have reduced functional outcome scores.

Figure A is an AP radiograph of the left shoulder revealing an AC joint injury with a CC distance of 25 mm. Figure B is a scapular Y radiograph confirming the AC joint injury. Figure C is an unlabeled diagram of the stabilizing ligaments of the clavicle. Illustration A is a labeled version of Figure C.

Incorrect Answers:
Answer 1: The coracoacromial ligament (labeled B) is generally spared in AC joint injuries.
Answer 2: The coracoacromial ligament (labeled B) is generally spared in AC joint injuries.
Answer 3: Both CC ligaments are generally injured in type III AC joint injuries (C and D).
Answer 5: The coracoacromial ligament (labeled B) is generally spared in AC joint injuries.