1. Acromioclavicular Joint Injuries

2. ANATOMY The AC joint is a diarthrodial joint located between the lateral end of the clavicle and the medial margin of the acromion process of the scapula. The articular surfaces initially are hyaline cartilage. A fibrocartilaginous disk of varying size and shape exists inside the joint. Viewed from the AP direction, the inclination of the joint may be almost vertical, or it may be inclined from downward medially, with the clavicle overriding the acromion by as much as 50 degrees

3. Acromioclavicular Ligaments The AC joint is surrounded by a thin capsule reinforced above, below, anteriorly, and posteriorly by the superior, inferior, anterior, and posterior AC ligaments. The fibers of the superior AC ligament, which is the strongest of the capsular ligaments, blend with the fibers of the deltoid and trapezius muscles, which are attached to the superior aspect of the clavicle and the acromion process. The AC ligaments stabilize the joint in an AP direction (the horizontal plane)

4. Coracoclavicular Ligament Suspensory ligaments of the upper extremity Two components: Trapezoid Conoid Stronger than AC ligaments Provide vertical stability to AC joint .

5. The horizontal stability is controlled by the AC ligament. The vertical stability is controlled by the coracoclavicular ligaments.

6. Function The coracoclavicular ligament helps to couple glenohumeral abduction and flexion to scapular rotation on the thorax. Full overhead elevation cannot be accomplished without combined and synchronous glenohumeral and scapulothoracic motion

7. Mechanisms of Injury The most common mechanism of injury is a direct force that occurs from a fall on the point of the shoulder. The weight of the suspended extremity and upward pull of the trapezius cause superior displacement Rarely, a severe force on the superior surface causes inferior displacement

8. Classification for Acromioclavicular Joint Injuries Initially classified by both Sage and Salvatore into three types (I, II, and III). Rockwood later added types IV, V, and VI, so that now six types are recognized. Classified depending on the degree and direction of displacement of the distal clavicle.

9. Type I Sprain of acromioclavicular ligament AC joint intact Coracoclavicular ligaments intact Deltoid and trapezius muscles intact

10. TYPE 2 AC joint disrupted < 50% Vertical displacement Sprain of the coracoclavicular ligaments CC ligaments intact Deltoid and trapezius muscles intact

11. TYPE 3 AC ligaments and CC ligaments all disrupted AC joint dislocated and the shoulder complex displaced inferiorly CC interspace greater than the normal shoulder(25-100%) Deltoid and trapezius muscles usually detached from the distal clavicle

12. Type III Variants Pseudodislocation through an intact periosteal sleeve Physeal injury Coracoid process fracture

13. TYPE 4 AC and CC ligaments disrupted AC joint dislocated and clavicle displaced posteriorly into or through the trapezius muscle Deltoid and trapezius muscles detached from the distal clavicle

14. TYPE 5 AC ligaments disrupted CC ligaments disrupted AC joint dislocated and gross disparity between the clavicle and the scapula (100- 300%) Deltoid and trapezius muscles detached from the distal half of clavicle

15. TYPE 6 AC joint dislocated and clavicle displaced inferior to the acromion or the coracoid process AC and CC ligaments disrupted Deltoid and trapezius muscles detached from the distal clavicle

16. Associated Injuries Scapulothoracic dissociation Fractures of the clavicle, SC joint, scapula Brachial plexus injury Osteolysis of distal clavicle

17. Exam Deformity and tenderness over AC joint Palpate entire clavicle and SC joint Assess neurovascular status Type III injuries can often be reduced with upward force on the elbow, while type IV and V injuries cannot

18. Radiographs AP or Zanca view (10 deg cephalic tilt) Most appropriate view Axillary look for posterior displacement Stryker notch view -(hand on head, 10 deg tilt) looks for coracoid fracture Stress (weighted) views- may help differentiate between type II and III injury

19. Zanca view Position of the patient for the Zanca view 10- to 15- degree cephalic tilt of the standard view for the AC joint

20. Stryker notch view Technique for taking the Stryker notch view to show fractures of the base of the coracoid. The patient is supine with a cassette placed posterior to the shoulder. The humerus is flexed approximately 120 degrees so the patient's hand can be placed on top of the head. The x-ray beam is directed 10 degrees superior.

21. Stress views

22. Treatment Type I injuries are satisfactorily treated nonsurgically. This usually includes application of ice, use of mild analgesics, immobilization with a sling, early range-of-motion exercises, and reinstitution of activities when comfort permits. Type II injuries should be treated similarly - strapping, splinting, or immobilization with a sling for 2 to 3 weeks. Heavy lifting or contact sports can be resumed after 6 weeks .

23. type III acromioclavicular joint separations may be treated nonoperatively initially with late reconstruction if necessary. In types IV, V, and VI injuries, displacement of the acromioclavicular joint would be too great to accept, and that open reduction and internal fixation are indicated.

24. Disadvantages of nonsurgical treatment (1) skin pressure and ulceration, (2) recurrence of deformity, (3) necessity of wearing the sling or brace for 8 weeks, (4) poor patient cooperation, (5) interference with activities of daily living, (6) loss of shoulder and elbow motion (in older patients), (7) soft-tissue calcification, (8) late acromioclavicular arthritis, and (9) late muscle atrophy, weakness, and fatigue.

25. Problems associated with surgical methods (1) infection; (2) anesthetic risk; (3) hematoma formation; (4) scar formation; (5) recurrence of deformity; (6) metal breakage, migration, and loosening; (7) breakage or loosening of sutures; (8) erosion or fracture of the distal clavicle; (9) postoperative pain and limitation of motion; (10) second procedure required for removal of fixation; (11) late acromioclavicular arthritis; and (12) soft- tissue calcification (usually insignificant)

26. Surgical options (1) acromioclavicular reduction and fixation; (2) acromioclavicular reduction, coracoclavicular ligament repair, and coracoclavicular fixation; (3) a combination of the first two categories; (4) distal clavicle excision; and (5) muscle transfers.

27. Acromioclavicular Pin Fixation

28. Coracoclavicular Screw Fixation

29. Indications for Late Surgical Treatment of Acromioclavicular Injuries Pain Weakness Deformity

30. Techniques for Late Surgical Treatment of Acromioclavicular Injuries Reduction of AC joint and repair of AC and CC ligaments Resection of distal clavicle and reconstruction of CC ligaments (Weaver-Dunn Procedure Transfer of the Coracoid to the Clavicle

31. Reconstruction of the Superior Acromioclavicular Ligament [Neviaser ]

32. Transfer of the Coracoid to the Clavicle Dewar and Barrington A, Normal anatomy. B, Acromioclavicular and coracoclavicular ligaments are torn, and acromioclavicular joint is dislocated. Hole has been drilled in end of coracoid, and pectoralis minor muscle has been divided in line with its fibers. C, End of coracoid has been osteotomized, transferred along with its attached muscles to clavicle, and fixed with screw. Dislocation of acromioclavicular joint is reduced.

33. Weaver-Dunn Procedure The distal clavicle is excised. The CA ligament is transferred to the distal clavicle. The CC ligaments are repaired and/or augmented with a coracoclavicular screw or suture. Repair of deltotrapezial fascia

34. Transfer of the Coracoacromial Ligament Rockwood

35. Pros and Cons of Operative Treatment Options for Acromioclavicular Joint Dislocations PROS CONS Intra-articular AC fixation Anatomic reduction Hardware failure or migration Distal clavicle osteolysis Extra-articular coracoclavicular repairs Superior strength of initial fixation (screw) Screw failure Bone resorption secondary to hardware Does not address soft tissue injury Ligament reconstruction Anatomic repair No risk of metallic hardware failure or retention Less initial fixation strength Harvest coracoacromial ligament

36. Thank you