Rockwood Children CH19

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CHAPTER 19 • Clavicle and Scapula Fractures and Acromioclavicular and Sternoclavicular Injuries

displace posteriorly, get entrapped in the trapezius muscle, and have a palpable prominence and tenderness medial and pos- terior to the acromion. These type IV injuries may be hard to diagnose unless examined specifically. Once an AC injury is suspected, the joint should be assessed for stability if possible. Typically, this needs to be done after the acute pain has subsided, approximately 5 to 7 days following the injury. Horizontal and vertical stabilities can be assessed and potentially the joint can be reduced by closed means. This is performed by stabilizing the clavicle with one hand and using the other hand to place an upward force under the ipsilateral elbow. Once the joint is reduced in the coronal plane, the mid- shaft of the clavicle can be grasped and translated in an anterior and posterior direction to assess horizontal stability. 137 Plain radiographs are the initial imaging modality of choice and should include a true AP view of the shoulder, an axillary lat- eral view of the shoulder, and a Zanca view to better visualize the AC joint. The Zanca view is performed with the patient in an upright position, allowing the injured arm to hang by the weight of gravity, and aiming the x-ray beam 10 to 15 degrees cephalad. 163 In addition, stress views can be performed, to dif- ferentiate between types II and III injuries, by having the patient hold a weight in each hand, with a single radiograph of the bilateral clavicles obtained. The posterior fracture dislocation (type IV) is often difficult to recognize by plain radiographs and may require a CT scan for accurate diagnosis. The classic description of acromioclavicular injuries for adults is that of Tossy et al. 148 and Allman 3 which was subsequently modified by Rockwood and colleagues (Fig. 19-12). 157 Type I injuries have normal radiographs with the only finding being tenderness to palpation over the AC joint due to a sprain of the AC ligaments. Type II injuries have disruption of the AC liga- ments and a sprain of the CC ligaments. The radiographs show a widened AC joint with slight vertical displacement demon- strated by a mild increase in the CC space. Type III injuries have disruption of the AC and CC ligaments with the radio- graphs showing the clavicle displaced superiorly relative to the acromion by 25% to 100% the width of the clavicle. Type IV injuries have disruption of the AC and CC ligaments as well as the deltopectoral fascia which allows for the clavicle to be pos- teriorly displaced into or through the trapezius muscle. Type V injuries have disruption of the AC and CC ligaments as well as the deltopectoral fascia with concomitant injury to the deltoid and trapezius muscle attachments to the clavicle. These injuries present with the clavicle displaced greater than 100% and lying in the subcutaneous tissue. Type VI injuries have disruption of the AC ligaments and deltopectoral fascia, but the CC ligaments remain intact. This occurs due to a high-energy mechanism of injury that causes the shoulder to be hyperabducted and exter- nally rotated. The end result is that the clavicle lies subacromial IMAGING AND OTHER DIAGNOSTIC STUDIES FOR ACROMIOCLAVICULAR DISLOCATIONS CLASSIFICATION OF ACROMIOCLAVICULAR DISLOCATIONS

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Figure 19-12.  Schematic depicting the Rockwood classification of acromioclavicular joint injuries.

or subcoracoid, with a resultant decrease in the CC distance seen on radiographs. The classification mentioned above has been modified for the pediatric and adolescent populations as true AC injuries are rare during skeletal immaturity compared with fractures of the distal clavicle. 35 Typically, the clavicle itself displaces out of the periosteal sleeve, leaving the periosteum attached to the CC and AC ligaments. The resultant clavicle injuries are then analogous to the six types described for the adult classification. OUTCOME MEASURES FOR ACROMIOCLAVICULAR DISLOCATIONS Typically, results of AC injuries have been reported based on subjective outcomes, the development of AC osteoarthritis, and range of motion. No outcome measures have been specifically applied to pediatric acromioclavicular injuries. Commonly utilized measures for adult AC joint injuries include the ASES score, the DASH Score, the QuickDASH, and the Constant Shoulder Score. The recent publication of a novel Pedi-ASES demonstrated that adult shoulder outcome scores such as the DASH and ASES surveys are associated with poor validity and comprehensibility in pediatric populations, and this new metric, when more comprehensively validated, may emerge as a future standard for use in pediatric and adolescent shoulder research. 59