Modified Weaver-Dunn Procedure for Acromioclavicular Joint Dislocations Andrew S
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1tips.qxd 2/2/04 10:33 AM Page 21 TIPS & TECHNIQUES Modified Weaver-Dunn Procedure for Acromioclavicular Joint Dislocations Andrew S. Rokito, MD Young Ho Oh, MD Joseph D. Zuckerman, MD primary suspensory structures for the The majority of acromioclavicular joint injuries result from upper extremity.8 Disruption of the direct trauma to the shoulder. The magnitude of applied acromio- or coracoclavicular ligaments results in variable degrees of acromio- force determines the degree of injury. This article presents a clavicular dislocations. modified Weaver-Dunn procedure consisting of lateral clavi- cle resection and reduction, coracoclavicular fixation with INJURY MECHANISM The majority of acromioclavicular suture or surgical tape, and coracoacromial ligament trans- joint injuries result from direct trauma fer for the treatment of these injuries. such as a blow to the shoulder. Usually, impact to the acromion with the humerus in an adducted position The acromioclavicular joint is com- size and shape is located within the joint results in acromioclavicular joint dis- monly affected by trauma to the shoul- and serves to improve its biomechanics ruption.9 Indirect trauma, such as a fall der girdle due to its subcutaneous posi- by decreasing contact stresses. The joint on an outstretched hand or flexed tion. Athletes who participate in contact orientation is variable with a medial elbow, forces the humeral head proxi- sports, such as hockey, football, rugby, inclination ranging from 10°-50° to the mally into the acromion.5,8 Most of and soccer, are particularly susceptible sagittal plane.6,7 these injuries are incomplete, involving to such injuries. These injuries, howev- The joint is stabilized by acromio- only the acromioclavicular ligaments. er, also occur during noncontact sports and coracoclavicular ligaments (Figure A force applied to the anterior such as baseball, skiing, and cycling. 1). Thickenings of the joint capsule aspect of the distal clavicle or posterior The majority of acromioclavicular in- form the anterior, posterior, superior, juries occur in men during the first 3 and inferior acromioclavicular liga- decades of life.1-5 ments. These ligaments confer horizon- tal stability to the acromioclavicular Share Your “Pearls” ANATOMY joint; the strongest is the superior liga- The acromioclavicular joint is a ment, which is reinforced by deltoid and Do you have a technique diarthrodial joint composed of the medi- trapezius insertional fibers.7,8 or tip to share? al acromial facet and distal clavicle end. The coracoclavicular ligaments con- ORTHOPEDICS wants to hear A fibrocartilaginous disk of variable sist of the conoid and trapezoid liga- from you. Tips & Techniques ments and extend from the inferior sur- manuscripts should be face of the distal clavicle to the base of submitted electronically at From New York University-Hospital for Joint Diseases, New York, NY. the coracoid process. These strong liga- www.rapidreview.com. Reprint requests: Young Ho Oh, MD, 305 ments provide vertical stability to the Second Ave, Ste 4, New York, NY 10003. acromioclavicular joint and serve as the www.orthobluejournal.com 21 1tips.qxd 2/2/04 10:33 AM Page 22 ORTHOPEDICS JANUARY 2004 VOL 27 NO 1 aspect of the acromion also leads to acromioclavicular joint injury. In rare instances, severe arm abduction results in subacromial or subcoracoid displace- ment of the clavicle. The magnitude of the applied force determines the degree of injury with the acromioclavicular lig- aments involved initially, followed by the coracoclavicular ligaments, and finally the deltoid and trapezius mus- cles. CLASSIFICATION Rockwood described six types of injuries to the acromioclavicular joint (Figure 2).1,2 This classification has proven useful in terms of prognosis and treatment. Type I injuries involve acromioclavic- 1 ular ligament sprain; the joint itself is not disrupted. In type II injuries, the acromioclavicular ligaments are com- pletely torn and the coracoclavicular lig- aments are sprained; this results in slight vertical subluxation of the clavicle. Type I and II injuries are incomplete in that the acromioclavicular joint is not dislocated. Type III injuries are complete and involve disruption of the acromio- and coracoclavicular ligaments, resulting in an acromioclavicular joint dislocation. The clavicle is displaced superiorly by 25%-100%. Type IV injuries also are complete; however, in these cases, the clavicle is displaced posteriorly into or through the trapezius muscle. Type V injuries are severe type III 2 injuries, in which detachment of the del- Figure 1: Anatomy of the acromioclavicular joint. Figure 2: Classification of injuries to the toid and trapezius from the distal clavi- acromioclavicular joint. Type I represents an acromioclavicular joint sprain. In type II injuries, the acromioclavicular ligaments are completely torn and the coracoclavicular cle is extensive, resulting in extreme ligaments are sprained. Type III injuries involve disruption of the acromioclavicular and superior displacement of the clavicle by coracoclavicular ligaments. In type IV injuries, the clavicle is displaced posteriorly in or 100%-300%. through the trapezius muscle. Type V injuries are severe type III injuries in which Type VI injuries, which are extreme- detachment of the deltoid and trapezius from the distal clavicle is extensive, resulting in ly rare, involve inferior dislocations of extreme superior displacement. Type VI injuries, which are rare, involve inferior dislocations of the acromioclavicular joint in which the clavicle is displaced in a the acromioclavicular joint in which the subacromial or subcoracoid position. clavicle is displaced into a subacromial or subcoracoid position. IMAGING Injuries to the acromioclavicular joint are readily assessed by plain radio- graphs; however, the acromioclavicular joint often is overpenetrated and poorly visualized with routine anteroposterior 22 www.orthobluejournal.com 1tips.qxd 2/2/04 10:33 AM Page 23 ROKITO ET AL TIPS & TECHNIQUES (AP) shoulder views. A 10°-15° cases towards nonoperative manage- vide downward pressure over the distal cephalic tilt is recommended to avoid ment.1-4,16-21 The controversy is a result, clavicle while directing a superior the scapular spine.10 This view is useful in part, of an earlier classification sys- force on the humerus.30 For this device to evaluate the degree of joint displace- tem in which type III injuries included to be effective, it had to be worn con- ment and intra-articular fractures. As types III, IV, and V injuries, which are tinuously for 6-8 weeks, holding the the appearance of the coracoclavicular now differentiated in the current classi- acromioclavicular joint in a reduced interval varies with the angle of the fication system.22 Consequently, the position. This device, which was cum- radiograph beam and the distance results of nonoperative treatment of bersome and painful to wear, often did between the beam and patient, both acute type III injuries would be more not maintain a satisfactory reduction. acromioclavicular joints should be variable in the prior classification sys- In addition, skin necrosis beneath the imaged simultaneously on a single tem due to the inclusion of severe dis- strap was a potential complication. For large cassette, whenever possible. placement cases (ie, types IV and V). these reasons, this device is no longer Axillary views reveal posterior dis- Prospective studies comparing non- used. placement of the distal clavicle and any operative and surgical treatment of type small intra-articular fractures. III injuries in the current classification Complete Injuries Some authors advocate stress radio- have shown similar results with no Various operative procedures have graphs when evaluating the acromio- advantage of either treatment.23-26 been described for the treatment of clavicular joint.1,2,5 Routine AP radio- Contact athletes, in particular, who sus- complete (types III-VI) acromioclavic- graphs are obtained with 10-15 lbs of tain type III injuries, often are treated ular joint injuries, including dynamic weight suspended or hung, rather than nonoperatively because of the high risk muscle transfers, acromioclavicular held; however, this may be too painful of reinjury. Some patients who sustain joint repairs, and coracoclavicular liga- in the acute situation. Although these type III injuries, however, particularly ment reconstructions with or without radiographic views have been advocated those involved in overhead sports or distal clavicle excision. to differentiate between type II and type heavy manual labor, develop persistent Transfer of the tip of the coracoid III injuries, an observation often not pain and mechanical symptoms that process and its attached conjoined ten- clinically relevant in terms of treatment, interfere with their ability to perform don to the undersurface of the clavicle is this distinction can often be made on their usual sport or job. This response described by several authors.31-35 The physical examination and with routine may be due, in part, to disruption of the transferred coracobrachialis and short AP views. normal synchronous scapuloclavicular head of the biceps stabilize the acromio- motion that occurs with overhead activ- clavicular joint by acting as dynamic TREATMENT OPTIONS ity. That possibility has led some authors depressors of the clavicle. As this proce- Type I and II Injuries to recommend surgical repair or recon- dure does not provide static stability, Most authors agree that the